diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-09-16 19:19:47 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-09-16 19:19:47 +0300 |
| commit | a430d95c5efa2b545d26a094eb5f624e36732af0 (patch) | |
| tree | df11f0f881c3959da82d9de5fa5310466255ff42 | |
| parent | ad060dbbcfcfcba624ef1a75e1d71365a98b86d8 (diff) | |
| parent | 19c9d55d72a9040cf9dc8de62633e6217381106b (diff) | |
| download | linux-a430d95c5efa2b545d26a094eb5f624e36732af0.tar.xz | |
Merge tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm
Pull lsm updates from Paul Moore:
- Move the LSM framework to static calls
This transitions the vast majority of the LSM callbacks into static
calls. Those callbacks which haven't been converted were left as-is
due to the general ugliness of the changes required to support the
static call conversion; we can revisit those callbacks at a future
date.
- Add the Integrity Policy Enforcement (IPE) LSM
This adds a new LSM, Integrity Policy Enforcement (IPE). There is
plenty of documentation about IPE in this patches, so I'll refrain
from going into too much detail here, but the basic motivation behind
IPE is to provide a mechanism such that administrators can restrict
execution to only those binaries which come from integrity protected
storage, e.g. a dm-verity protected filesystem. You will notice that
IPE requires additional LSM hooks in the initramfs, dm-verity, and
fs-verity code, with the associated patches carrying ACK/review tags
from the associated maintainers. We couldn't find an obvious
maintainer for the initramfs code, but the IPE patchset has been
widely posted over several years.
Both Deven Bowers and Fan Wu have contributed to IPE's development
over the past several years, with Fan Wu agreeing to serve as the IPE
maintainer moving forward. Once IPE is accepted into your tree, I'll
start working with Fan to ensure he has the necessary accounts, keys,
etc. so that he can start submitting IPE pull requests to you
directly during the next merge window.
- Move the lifecycle management of the LSM blobs to the LSM framework
Management of the LSM blobs (the LSM state buffers attached to
various kernel structs, typically via a void pointer named "security"
or similar) has been mixed, some blobs were allocated/managed by
individual LSMs, others were managed by the LSM framework itself.
Starting with this pull we move management of all the LSM blobs,
minus the XFRM blob, into the framework itself, improving consistency
across LSMs, and reducing the amount of duplicated code across LSMs.
Due to some additional work required to migrate the XFRM blob, it has
been left as a todo item for a later date; from a practical
standpoint this omission should have little impact as only SELinux
provides a XFRM LSM implementation.
- Fix problems with the LSM's handling of F_SETOWN
The LSM hook for the fcntl(F_SETOWN) operation had a couple of
problems: it was racy with itself, and it was disconnected from the
associated DAC related logic in such a way that the LSM state could
be updated in cases where the DAC state would not. We fix both of
these problems by moving the security_file_set_fowner() hook into the
same section of code where the DAC attributes are updated. Not only
does this resolve the DAC/LSM synchronization issue, but as that code
block is protected by a lock, it also resolve the race condition.
- Fix potential problems with the security_inode_free() LSM hook
Due to use of RCU to protect inodes and the placement of the LSM hook
associated with freeing the inode, there is a bit of a challenge when
it comes to managing any LSM state associated with an inode. The VFS
folks are not open to relocating the LSM hook so we have to get
creative when it comes to releasing an inode's LSM state.
Traditionally we have used a single LSM callback within the hook that
is triggered when the inode is "marked for death", but not actually
released due to RCU.
Unfortunately, this causes problems for LSMs which want to take an
action when the inode's associated LSM state is actually released; so
we add an additional LSM callback, inode_free_security_rcu(), that is
called when the inode's LSM state is released in the RCU free
callback.
- Refactor two LSM hooks to better fit the LSM return value patterns
The vast majority of the LSM hooks follow the "return 0 on success,
negative values on failure" pattern, however, there are a small
handful that have unique return value behaviors which has caused
confusion in the past and makes it difficult for the BPF verifier to
properly vet BPF LSM programs. This includes patches to
convert two of these"special" LSM hooks to the common 0/-ERRNO pattern.
- Various cleanups and improvements
A handful of patches to remove redundant code, better leverage the
IS_ERR_OR_NULL() helper, add missing "static" markings, and do some
minor style fixups.
* tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (40 commits)
security: Update file_set_fowner documentation
fs: Fix file_set_fowner LSM hook inconsistencies
lsm: Use IS_ERR_OR_NULL() helper function
lsm: remove LSM_COUNT and LSM_CONFIG_COUNT
ipe: Remove duplicated include in ipe.c
lsm: replace indirect LSM hook calls with static calls
lsm: count the LSMs enabled at compile time
kernel: Add helper macros for loop unrolling
init/main.c: Initialize early LSMs after arch code, static keys and calls.
MAINTAINERS: add IPE entry with Fan Wu as maintainer
documentation: add IPE documentation
ipe: kunit test for parser
scripts: add boot policy generation program
ipe: enable support for fs-verity as a trust provider
fsverity: expose verified fsverity built-in signatures to LSMs
lsm: add security_inode_setintegrity() hook
ipe: add support for dm-verity as a trust provider
dm-verity: expose root hash digest and signature data to LSMs
block,lsm: add LSM blob and new LSM hooks for block devices
ipe: add permissive toggle
...
71 files changed, 6062 insertions, 483 deletions
diff --git a/Documentation/admin-guide/LSM/index.rst b/Documentation/admin-guide/LSM/index.rst index a6ba95fbaa9f..ce63be6d64ad 100644 --- a/Documentation/admin-guide/LSM/index.rst +++ b/Documentation/admin-guide/LSM/index.rst @@ -47,3 +47,4 @@ subdirectories. tomoyo Yama SafeSetID + ipe diff --git a/Documentation/admin-guide/LSM/ipe.rst b/Documentation/admin-guide/LSM/ipe.rst new file mode 100644 index 000000000000..f38e641df0e9 --- /dev/null +++ b/Documentation/admin-guide/LSM/ipe.rst @@ -0,0 +1,790 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Integrity Policy Enforcement (IPE) +================================== + +.. NOTE:: + + This is the documentation for admins, system builders, or individuals + attempting to use IPE. If you're looking for more developer-focused + documentation about IPE please see :doc:`the design docs </security/ipe>`. + +Overview +-------- + +Integrity Policy Enforcement (IPE) is a Linux Security Module that takes a +complementary approach to access control. Unlike traditional access control +mechanisms that rely on labels and paths for decision-making, IPE focuses +on the immutable security properties inherent to system components. These +properties are fundamental attributes or features of a system component +that cannot be altered, ensuring a consistent and reliable basis for +security decisions. + +To elaborate, in the context of IPE, system components primarily refer to +files or the devices these files reside on. However, this is just a +starting point. The concept of system components is flexible and can be +extended to include new elements as the system evolves. The immutable +properties include the origin of a file, which remains constant and +unchangeable over time. For example, IPE policies can be crafted to trust +files originating from the initramfs. Since initramfs is typically verified +by the bootloader, its files are deemed trustworthy; "file is from +initramfs" becomes an immutable property under IPE's consideration. + +The immutable property concept extends to the security features enabled on +a file's origin, such as dm-verity or fs-verity, which provide a layer of +integrity and trust. For example, IPE allows the definition of policies +that trust files from a dm-verity protected device. dm-verity ensures the +integrity of an entire device by providing a verifiable and immutable state +of its contents. Similarly, fs-verity offers filesystem-level integrity +checks, allowing IPE to enforce policies that trust files protected by +fs-verity. These two features cannot be turned off once established, so +they are considered immutable properties. These examples demonstrate how +IPE leverages immutable properties, such as a file's origin and its +integrity protection mechanisms, to make access control decisions. + +For the IPE policy, specifically, it grants the ability to enforce +stringent access controls by assessing security properties against +reference values defined within the policy. This assessment can be based on +the existence of a security property (e.g., verifying if a file originates +from initramfs) or evaluating the internal state of an immutable security +property. The latter includes checking the roothash of a dm-verity +protected device, determining whether dm-verity possesses a valid +signature, assessing the digest of a fs-verity protected file, or +determining whether fs-verity possesses a valid built-in signature. This +nuanced approach to policy enforcement enables a highly secure and +customizable system defense mechanism, tailored to specific security +requirements and trust models. + +To enable IPE, ensure that ``CONFIG_SECURITY_IPE`` (under +:menuselection:`Security -> Integrity Policy Enforcement (IPE)`) config +option is enabled. + +Use Cases +--------- + +IPE works best in fixed-function devices: devices in which their purpose +is clearly defined and not supposed to be changed (e.g. network firewall +device in a data center, an IoT device, etcetera), where all software and +configuration is built and provisioned by the system owner. + +IPE is a long-way off for use in general-purpose computing: the Linux +community as a whole tends to follow a decentralized trust model (known as +the web of trust), which IPE has no support for it yet. Instead, IPE +supports PKI (public key infrastructure), which generally designates a +set of trusted entities that provide a measure of absolute trust. + +Additionally, while most packages are signed today, the files inside +the packages (for instance, the executables), tend to be unsigned. This +makes it difficult to utilize IPE in systems where a package manager is +expected to be functional, without major changes to the package manager +and ecosystem behind it. + +The digest_cache LSM [#digest_cache_lsm]_ is a system that when combined with IPE, +could be used to enable and support general-purpose computing use cases. + +Known Limitations +----------------- + +IPE cannot verify the integrity of anonymous executable memory, such as +the trampolines created by gcc closures and libffi (<3.4.2), or JIT'd code. +Unfortunately, as this is dynamically generated code, there is no way +for IPE to ensure the integrity of this code to form a trust basis. + +IPE cannot verify the integrity of programs written in interpreted +languages when these scripts are invoked by passing these program files +to the interpreter. This is because the way interpreters execute these +files; the scripts themselves are not evaluated as executable code +through one of IPE's hooks, but they are merely text files that are read +(as opposed to compiled executables) [#interpreters]_. + +Threat Model +------------ + +IPE specifically targets the risk of tampering with user-space executable +code after the kernel has initially booted, including the kernel modules +loaded from userspace via ``modprobe`` or ``insmod``. + +To illustrate, consider a scenario where an untrusted binary, possibly +malicious, is downloaded along with all necessary dependencies, including a +loader and libc. The primary function of IPE in this context is to prevent +the execution of such binaries and their dependencies. + +IPE achieves this by verifying the integrity and authenticity of all +executable code before allowing them to run. It conducts a thorough +check to ensure that the code's integrity is intact and that they match an +authorized reference value (digest, signature, etc) as per the defined +policy. If a binary does not pass this verification process, either +because its integrity has been compromised or it does not meet the +authorization criteria, IPE will deny its execution. Additionally, IPE +generates audit logs which may be utilized to detect and analyze failures +resulting from policy violation. + +Tampering threat scenarios include modification or replacement of +executable code by a range of actors including: + +- Actors with physical access to the hardware +- Actors with local network access to the system +- Actors with access to the deployment system +- Compromised internal systems under external control +- Malicious end users of the system +- Compromised end users of the system +- Remote (external) compromise of the system + +IPE does not mitigate threats arising from malicious but authorized +developers (with access to a signing certificate), or compromised +developer tools used by them (i.e. return-oriented programming attacks). +Additionally, IPE draws hard security boundary between userspace and +kernelspace. As a result, kernel-level exploits are considered outside +the scope of IPE and mitigation is left to other mechanisms. + +Policy +------ + +IPE policy is a plain-text [#devdoc]_ policy composed of multiple statements +over several lines. There is one required line, at the top of the +policy, indicating the policy name, and the policy version, for +instance:: + + policy_name=Ex_Policy policy_version=0.0.0 + +The policy name is a unique key identifying this policy in a human +readable name. This is used to create nodes under securityfs as well as +uniquely identify policies to deploy new policies vs update existing +policies. + +The policy version indicates the current version of the policy (NOT the +policy syntax version). This is used to prevent rollback of policy to +potentially insecure previous versions of the policy. + +The next portion of IPE policy are rules. Rules are formed by key=value +pairs, known as properties. IPE rules require two properties: ``action``, +which determines what IPE does when it encounters a match against the +rule, and ``op``, which determines when the rule should be evaluated. +The ordering is significant, a rule must start with ``op``, and end with +``action``. Thus, a minimal rule is:: + + op=EXECUTE action=ALLOW + +This example will allow any execution. Additional properties are used to +assess immutable security properties about the files being evaluated. +These properties are intended to be descriptions of systems within the +kernel that can provide a measure of integrity verification, such that IPE +can determine the trust of the resource based on the value of the property. + +Rules are evaluated top-to-bottom. As a result, any revocation rules, +or denies should be placed early in the file to ensure that these rules +are evaluated before a rule with ``action=ALLOW``. + +IPE policy supports comments. The character '#' will function as a +comment, ignoring all characters to the right of '#' until the newline. + +The default behavior of IPE evaluations can also be expressed in policy, +through the ``DEFAULT`` statement. This can be done at a global level, +or a per-operation level:: + + # Global + DEFAULT action=ALLOW + + # Operation Specific + DEFAULT op=EXECUTE action=ALLOW + +A default must be set for all known operations in IPE. If you want to +preserve older policies being compatible with newer kernels that can introduce +new operations, set a global default of ``ALLOW``, then override the +defaults on a per-operation basis (as above). + +With configurable policy-based LSMs, there's several issues with +enforcing the configurable policies at startup, around reading and +parsing the policy: + +1. The kernel *should* not read files from userspace, so directly reading + the policy file is prohibited. +2. The kernel command line has a character limit, and one kernel module + should not reserve the entire character limit for its own + configuration. +3. There are various boot loaders in the kernel ecosystem, so handing + off a memory block would be costly to maintain. + +As a result, IPE has addressed this problem through a concept of a "boot +policy". A boot policy is a minimal policy which is compiled into the +kernel. This policy is intended to get the system to a state where +userspace is set up and ready to receive commands, at which point a more +complex policy can be deployed via securityfs. The boot policy can be +specified via ``SECURITY_IPE_BOOT_POLICY`` config option, which accepts +a path to a plain-text version of the IPE policy to apply. This policy +will be compiled into the kernel. If not specified, IPE will be disabled +until a policy is deployed and activated through securityfs. + +Deploying Policies +~~~~~~~~~~~~~~~~~~ + +Policies can be deployed from userspace through securityfs. These policies +are signed through the PKCS#7 message format to enforce some level of +authorization of the policies (prohibiting an attacker from gaining +unconstrained root, and deploying an "allow all" policy). These +policies must be signed by a certificate that chains to the +``SYSTEM_TRUSTED_KEYRING``. With openssl, the policy can be signed by:: + + openssl smime -sign \ + -in "$MY_POLICY" \ + -signer "$MY_CERTIFICATE" \ + -inkey "$MY_PRIVATE_KEY" \ + -noattr \ + -nodetach \ + -nosmimecap \ + -outform der \ + -out "$MY_POLICY.p7b" + +Deploying the policies is done through securityfs, through the +``new_policy`` node. To deploy a policy, simply cat the file into the +securityfs node:: + + cat "$MY_POLICY.p7b" > /sys/kernel/security/ipe/new_policy + +Upon success, this will create one subdirectory under +``/sys/kernel/security/ipe/policies/``. The subdirectory will be the +``policy_name`` field of the policy deployed, so for the example above, +the directory will be ``/sys/kernel/security/ipe/policies/Ex_Policy``. +Within this directory, there will be seven files: ``pkcs7``, ``policy``, +``name``, ``version``, ``active``, ``update``, and ``delete``. + +The ``pkcs7`` file is read-only. Reading it returns the raw PKCS#7 data +that was provided to the kernel, representing the policy. If the policy being +read is the boot policy, this will return ``ENOENT``, as it is not signed. + +The ``policy`` file is read only. Reading it returns the PKCS#7 inner +content of the policy, which will be the plain text policy. + +The ``active`` file is used to set a policy as the currently active policy. +This file is rw, and accepts a value of ``"1"`` to set the policy as active. +Since only a single policy can be active at one time, all other policies +will be marked inactive. The policy being marked active must have a policy +version greater or equal to the currently-running version. + +The ``update`` file is used to update a policy that is already present +in the kernel. This file is write-only and accepts a PKCS#7 signed +policy. Two checks will always be performed on this policy: First, the +``policy_names`` must match with the updated version and the existing +version. Second the updated policy must have a policy version greater than +or equal to the currently-running version. This is to prevent rollback attacks. + +The ``delete`` file is used to remove a policy that is no longer needed. +This file is write-only and accepts a value of ``1`` to delete the policy. +On deletion, the securityfs node representing the policy will be removed. +However, delete the current active policy is not allowed and will return +an operation not permitted error. + +Similarly, writing to both ``update`` and ``new_policy`` could result in +bad message(policy syntax error) or file exists error. The latter error happens +when trying to deploy a policy with a ``policy_name`` while the kernel already +has a deployed policy with the same ``policy_name``. + +Deploying a policy will *not* cause IPE to start enforcing the policy. IPE will +only enforce the policy marked active. Note that only one policy can be active +at a time. + +Once deployment is successful, the policy can be activated, by writing file +``/sys/kernel/security/ipe/policies/$policy_name/active``. +For example, the ``Ex_Policy`` can be activated by:: + + echo 1 > "/sys/kernel/security/ipe/policies/Ex_Policy/active" + +From above point on, ``Ex_Policy`` is now the enforced policy on the +system. + +IPE also provides a way to delete policies. This can be done via the +``delete`` securityfs node, +``/sys/kernel/security/ipe/policies/$policy_name/delete``. +Writing ``1`` to that file deletes the policy:: + + echo 1 > "/sys/kernel/security/ipe/policies/$policy_name/delete" + +There is only one requirement to delete a policy: the policy being deleted +must be inactive. + +.. NOTE:: + + If a traditional MAC system is enabled (SELinux, apparmor, smack), all + writes to ipe's securityfs nodes require ``CAP_MAC_ADMIN``. + +Modes +~~~~~ + +IPE supports two modes of operation: permissive (similar to SELinux's +permissive mode) and enforced. In permissive mode, all events are +checked and policy violations are logged, but the policy is not really +enforced. This allows users to test policies before enforcing them. + +The default mode is enforce, and can be changed via the kernel command +line parameter ``ipe.enforce=(0|1)``, or the securityfs node +``/sys/kernel/security/ipe/enforce``. + +.. NOTE:: + + If a traditional MAC system is enabled (SELinux, apparmor, smack, etcetera), + all writes to ipe's securityfs nodes require ``CAP_MAC_ADMIN``. + +Audit Events +~~~~~~~~~~~~ + +1420 AUDIT_IPE_ACCESS +^^^^^^^^^^^^^^^^^^^^^ +Event Examples:: + + type=1420 audit(1653364370.067:61): ipe_op=EXECUTE ipe_hook=MMAP enforcing=1 pid=2241 comm="ld-linux.so" path="/deny/lib/libc.so.6" dev="sda2" ino=14549020 rule="DEFAULT action=DENY" + type=1300 audit(1653364370.067:61): SYSCALL arch=c000003e syscall=9 success=no exit=-13 a0=7f1105a28000 a1=195000 a2=5 a3=812 items=0 ppid=2219 pid=2241 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=2 comm="ld-linux.so" exe="/tmp/ipe-test/lib/ld-linux.so" subj=unconfined key=(null) + type=1327 audit(1653364370.067:61): 707974686F6E3300746573742F6D61696E2E7079002D6E00 + + type=1420 audit(1653364735.161:64): ipe_op=EXECUTE ipe_hook=MMAP enforcing=1 pid=2472 comm="mmap_test" path=? dev=? ino=? rule="DEFAULT action=DENY" + type=1300 audit(1653364735.161:64): SYSCALL arch=c000003e syscall=9 success=no exit=-13 a0=0 a1=1000 a2=4 a3=21 items=0 ppid=2219 pid=2472 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=2 comm="mmap_test" exe="/root/overlake_test/upstream_test/vol_fsverity/bin/mmap_test" subj=unconfined key=(null) + type=1327 audit(1653364735.161:64): 707974686F6E3300746573742F6D61696E2E7079002D6E00 + +This event indicates that IPE made an access control decision; the IPE +specific record (1420) is always emitted in conjunction with a +``AUDITSYSCALL`` record. + +Determining whether IPE is in permissive or enforced mode can be derived +from ``success`` property and exit code of the ``AUDITSYSCALL`` record. + + +Field descriptions: + ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| Field | Value Type | Optional? | Description of Value | ++===========+============+===========+=================================================================================+ +| ipe_op | string | No | The IPE operation name associated with the log | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| ipe_hook | string | No | The name of the LSM hook that triggered the IPE event | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| enforcing | integer | No | The current IPE enforcing state 1 is in enforcing mode, 0 is in permissive mode | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| pid | integer | No | The pid of the process that triggered the IPE event. | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| comm | string | No | The command line program name of the process that triggered the IPE event | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| path | string | Yes | The absolute path to the evaluated file | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| ino | integer | Yes | The inode number of the evaluated file | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| dev | string | Yes | The device name of the evaluated file, e.g. vda | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ +| rule | string | No | The matched policy rule | ++-----------+------------+-----------+---------------------------------------------------------------------------------+ + +1421 AUDIT_IPE_CONFIG_CHANGE +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Event Example:: + + type=1421 audit(1653425583.136:54): old_active_pol_name="Allow_All" old_active_pol_version=0.0.0 old_policy_digest=sha256:E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855 new_active_pol_name="boot_verified" new_active_pol_version=0.0.0 new_policy_digest=sha256:820EEA5B40CA42B51F68962354BA083122A20BB846F26765076DD8EED7B8F4DB auid=4294967295 ses=4294967295 lsm=ipe res=1 + type=1300 audit(1653425583.136:54): SYSCALL arch=c000003e syscall=1 success=yes exit=2 a0=3 a1=5596fcae1fb0 a2=2 a3=2 items=0 ppid=184 pid=229 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=4294967295 comm="python3" exe="/usr/bin/python3.10" key=(null) + type=1327 audit(1653425583.136:54): PROCTITLE proctitle=707974686F6E3300746573742F6D61696E2E7079002D66002E2 + +This event indicates that IPE switched the active poliy from one to another +along with the version and the hash digest of the two policies. +Note IPE can only have one policy active at a time, all access decision +evaluation is based on the current active policy. +The normal procedure to deploy a new policy is loading the policy to deploy +into the kernel first, then switch the active policy to it. + +This record will always be emitted in conjunction with a ``AUDITSYSCALL`` record for the ``write`` syscall. + +Field descriptions: + ++------------------------+------------+-----------+---------------------------------------------------+ +| Field | Value Type | Optional? | Description of Value | ++========================+============+===========+===================================================+ +| old_active_pol_name | string | Yes | The name of previous active policy | ++------------------------+------------+-----------+---------------------------------------------------+ +| old_active_pol_version | string | Yes | The version of previous active policy | ++------------------------+------------+-----------+---------------------------------------------------+ +| old_policy_digest | string | Yes | The hash of previous active policy | ++------------------------+------------+-----------+---------------------------------------------------+ +| new_active_pol_name | string | No | The name of current active policy | ++------------------------+------------+-----------+---------------------------------------------------+ +| new_active_pol_version | string | No | The version of current active policy | ++------------------------+------------+-----------+---------------------------------------------------+ +| new_policy_digest | string | No | The hash of current active policy | ++------------------------+------------+-----------+---------------------------------------------------+ +| auid | integer | No | The login user ID | ++------------------------+------------+-----------+---------------------------------------------------+ +| ses | integer | No | The login session ID | ++------------------------+------------+-----------+---------------------------------------------------+ +| lsm | string | No | The lsm name associated with the event | ++------------------------+------------+-----------+---------------------------------------------------+ +| res | integer | No | The result of the audited operation(success/fail) | ++------------------------+------------+-----------+---------------------------------------------------+ + +1422 AUDIT_IPE_POLICY_LOAD +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Event Example:: + + type=1422 audit(1653425529.927:53): policy_name="boot_verified" policy_version=0.0.0 policy_digest=sha256:820EEA5B40CA42B51F68962354BA083122A20BB846F26765076DD8EED7B8F4DB auid=4294967295 ses=4294967295 lsm=ipe res=1 + type=1300 audit(1653425529.927:53): arch=c000003e syscall=1 success=yes exit=2567 a0=3 a1=5596fcae1fb0 a2=a07 a3=2 items=0 ppid=184 pid=229 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=4294967295 comm="python3" exe="/usr/bin/python3.10" key=(null) + type=1327 audit(1653425529.927:53): PROCTITLE proctitle=707974686F6E3300746573742F6D61696E2E7079002D66002E2E + +This record indicates a new policy has been loaded into the kernel with the policy name, policy version and policy hash. + +This record will always be emitted in conjunction with a ``AUDITSYSCALL`` record for the ``write`` syscall. + +Field descriptions: + ++----------------+------------+-----------+---------------------------------------------------+ +| Field | Value Type | Optional? | Description of Value | ++================+============+===========+===================================================+ +| policy_name | string | No | The policy_name | ++----------------+------------+-----------+---------------------------------------------------+ +| policy_version | string | No | The policy_version | ++----------------+------------+-----------+---------------------------------------------------+ +| policy_digest | string | No | The policy hash | ++----------------+------------+-----------+---------------------------------------------------+ +| auid | integer | No | The login user ID | ++----------------+------------+-----------+---------------------------------------------------+ +| ses | integer | No | The login session ID | ++----------------+------------+-----------+---------------------------------------------------+ +| lsm | string | No | The lsm name associated with the event | ++----------------+------------+-----------+---------------------------------------------------+ +| res | integer | No | The result of the audited operation(success/fail) | ++----------------+------------+-----------+---------------------------------------------------+ + + +1404 AUDIT_MAC_STATUS +^^^^^^^^^^^^^^^^^^^^^ + +Event Examples:: + + type=1404 audit(1653425689.008:55): enforcing=0 old_enforcing=1 auid=4294967295 ses=4294967295 enabled=1 old-enabled=1 lsm=ipe res=1 + type=1300 audit(1653425689.008:55): arch=c000003e syscall=1 success=yes exit=2 a0=1 a1=55c1065e5c60 a2=2 a3=0 items=0 ppid=405 pid=441 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=) + type=1327 audit(1653425689.008:55): proctitle="-bash" + + type=1404 audit(1653425689.008:55): enforcing=1 old_enforcing=0 auid=4294967295 ses=4294967295 enabled=1 old-enabled=1 lsm=ipe res=1 + type=1300 audit(1653425689.008:55): arch=c000003e syscall=1 success=yes exit=2 a0=1 a1=55c1065e5c60 a2=2 a3=0 items=0 ppid=405 pid=441 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=) + type=1327 audit(1653425689.008:55): proctitle="-bash" + +This record will always be emitted in conjunction with a ``AUDITSYSCALL`` record for the ``write`` syscall. + +Field descriptions: + ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ +| Field | Value Type | Optional? | Description of Value | ++===============+============+===========+=================================================================================================+ +| enforcing | integer | No | The enforcing state IPE is being switched to, 1 is in enforcing mode, 0 is in permissive mode | ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ +| old_enforcing | integer | No | The enforcing state IPE is being switched from, 1 is in enforcing mode, 0 is in permissive mode | ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ +| auid | integer | No | The login user ID | ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ +| ses | integer | No | The login session ID | ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ +| enabled | integer | No | The new TTY audit enabled setting | ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ +| old-enabled | integer | No | The old TTY audit enabled setting | ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ +| lsm | string | No | The lsm name associated with the event | ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ +| res | integer | No | The result of the audited operation(success/fail) | ++---------------+------------+-----------+-------------------------------------------------------------------------------------------------+ + + +Success Auditing +^^^^^^^^^^^^^^^^ + +IPE supports success auditing. When enabled, all events that pass IPE +policy and are not blocked will emit an audit event. This is disabled by +default, and can be enabled via the kernel command line +``ipe.success_audit=(0|1)`` or +``/sys/kernel/security/ipe/success_audit`` securityfs file. + +This is *very* noisy, as IPE will check every userspace binary on the +system, but is useful for debugging policies. + +.. NOTE:: + + If a traditional MAC system is enabled (SELinux, apparmor, smack, etcetera), + all writes to ipe's securityfs nodes require ``CAP_MAC_ADMIN``. + +Properties +---------- + +As explained above, IPE properties are ``key=value`` pairs expressed in IPE +policy. Two properties are built-into the policy parser: 'op' and 'action'. +The other properties are used to restrict immutable security properties +about the files being evaluated. Currently those properties are: +'``boot_verified``', '``dmverity_signature``', '``dmverity_roothash``', +'``fsverity_signature``', '``fsverity_digest``'. A description of all +properties supported by IPE are listed below: + +op +~~ + +Indicates the operation for a rule to apply to. Must be in every rule, +as the first token. IPE supports the following operations: + + ``EXECUTE`` + + Pertains to any file attempting to be executed, or loaded as an + executable. + + ``FIRMWARE``: + + Pertains to firmware being loaded via the firmware_class interface. + This covers both the preallocated buffer and the firmware file + itself. + + ``KMODULE``: + + Pertains to loading kernel modules via ``modprobe`` or ``insmod``. + + ``KEXEC_IMAGE``: + + Pertains to kernel images loading via ``kexec``. + + ``KEXEC_INITRAMFS`` + + Pertains to initrd images loading via ``kexec --initrd``. + + ``POLICY``: + + Controls loading policies via reading a kernel-space initiated read. + + An example of such is loading IMA policies by writing the path + to the policy file to ``$securityfs/ima/policy`` + + ``X509_CERT``: + + Controls loading IMA certificates through the Kconfigs, + ``CONFIG_IMA_X509_PATH`` and ``CONFIG_EVM_X509_PATH``. + +action +~~~~~~ + + Determines what IPE should do when a rule matches. Must be in every + rule, as the final clause. Can be one of: + + ``ALLOW``: + + If the rule matches, explicitly allow access to the resource to proceed + without executing any more rules. + + ``DENY``: + + If the rule matches, explicitly prohibit access to the resource to + proceed without executing any more rules. + +boot_verified +~~~~~~~~~~~~~ + + This property can be utilized for authorization of files from initramfs. + The format of this property is:: + + boot_verified=(TRUE|FALSE) + + + .. WARNING:: + + This property will trust files from initramfs(rootfs). It should + only be used during early booting stage. Before mounting the real + rootfs on top of the initramfs, initramfs script will recursively + remove all files and directories on the initramfs. This is typically + implemented by using switch_root(8) [#switch_root]_. Therefore the + initramfs will be empty and not accessible after the real + rootfs takes over. It is advised to switch to a different policy + that doesn't rely on the property after this point. + This ensures that the trust policies remain relevant and effective + throughout the system's operation. + +dmverity_roothash +~~~~~~~~~~~~~~~~~ + + This property can be utilized for authorization or revocation of + specific dm-verity volumes, identified via their root hashes. It has a + dependency on the DM_VERITY module. This property is controlled by + the ``IPE_PROP_DM_VERITY`` config option, it will be automatically + selected when ``SECURITY_IPE`` and ``DM_VERITY`` are all enabled. + The format of this property is:: + + dmverity_roothash=DigestName:HexadecimalString + + The supported DigestNames for dmverity_roothash are [#dmveritydigests]_ + + + blake2b-512 + + blake2s-256 + + sha256 + + sha384 + + sha512 + + sha3-224 + + sha3-256 + + sha3-384 + + sha3-512 + + sm3 + + rmd160 + +dmverity_signature +~~~~~~~~~~~~~~~~~~ + + This property can be utilized for authorization of all dm-verity + volumes that have a signed roothash that validated by a keyring + specified by dm-verity's configuration, either the system trusted + keyring, or the secondary keyring. It depends on + ``DM_VERITY_VERIFY_ROOTHASH_SIG`` config option and is controlled by + the ``IPE_PROP_DM_VERITY_SIGNATURE`` config option, it will be automatically + selected when ``SECURITY_IPE``, ``DM_VERITY`` and + ``DM_VERITY_VERIFY_ROOTHASH_SIG`` are all enabled. + The format of this property is:: + + dmverity_signature=(TRUE|FALSE) + +fsverity_digest +~~~~~~~~~~~~~~~ + + This property can be utilized for authorization of specific fsverity + enabled files, identified via their fsverity digests. + It depends on ``FS_VERITY`` config option and is controlled by + the ``IPE_PROP_FS_VERITY`` config option, it will be automatically + selected when ``SECURITY_IPE`` and ``FS_VERITY`` are all enabled. + The format of this property is:: + + fsverity_digest=DigestName:HexadecimalString + + The supported DigestNames for fsverity_digest are [#fsveritydigest]_ + + + sha256 + + sha512 + +fsverity_signature +~~~~~~~~~~~~~~~~~~ + + This property is used to authorize all fs-verity enabled files that have + been verified by fs-verity's built-in signature mechanism. The signature + verification relies on a key stored within the ".fs-verity" keyring. It + depends on ``FS_VERITY_BUILTIN_SIGNATURES`` config option and + it is controlled by the ``IPE_PROP_FS_VERITY`` config option, + it will be automatically selected when ``SECURITY_IPE``, ``FS_VERITY`` + and ``FS_VERITY_BUILTIN_SIGNATURES`` are all enabled. + The format of this property is:: + + fsverity_signature=(TRUE|FALSE) + +Policy Examples +--------------- + +Allow all +~~~~~~~~~ + +:: + + policy_name=Allow_All policy_version=0.0.0 + DEFAULT action=ALLOW + +Allow only initramfs +~~~~~~~~~~~~~~~~~~~~ + +:: + + policy_name=Allow_Initramfs policy_version=0.0.0 + DEFAULT action=DENY + + op=EXECUTE boot_verified=TRUE action=ALLOW + +Allow any signed and validated dm-verity volume and the initramfs +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + policy_name=Allow_Signed_DMV_And_Initramfs policy_version=0.0.0 + DEFAULT action=DENY + + op=EXECUTE boot_verified=TRUE action=ALLOW + op=EXECUTE dmverity_signature=TRUE action=ALLOW + +Prohibit execution from a specific dm-verity volume +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + policy_name=Deny_DMV_By_Roothash policy_version=0.0.0 + DEFAULT action=DENY + + op=EXECUTE dmverity_roothash=sha256:cd2c5bae7c6c579edaae4353049d58eb5f2e8be0244bf05345bc8e5ed257baff action=DENY + + op=EXECUTE boot_verified=TRUE action=ALLOW + op=EXECUTE dmverity_signature=TRUE action=ALLOW + +Allow only a specific dm-verity volume +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + policy_name=Allow_DMV_By_Roothash policy_version=0.0.0 + DEFAULT action=DENY + + op=EXECUTE dmverity_roothash=sha256:401fcec5944823ae12f62726e8184407a5fa9599783f030dec146938 action=ALLOW + +Allow any fs-verity file with a valid built-in signature +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + policy_name=Allow_Signed_And_Validated_FSVerity policy_version=0.0.0 + DEFAULT action=DENY + + op=EXECUTE fsverity_signature=TRUE action=ALLOW + +Allow execution of a specific fs-verity file +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + policy_name=ALLOW_FSV_By_Digest policy_version=0.0.0 + DEFAULT action=DENY + + op=EXECUTE fsverity_digest=sha256:fd88f2b8824e197f850bf4c5109bea5cf0ee38104f710843bb72da796ba5af9e action=ALLOW + +Additional Information +---------------------- + +- `Github Repository <https://github.com/microsoft/ipe>`_ +- :doc:`Developer and design docs for IPE </security/ipe>` + +FAQ +--- + +Q: + What's the difference between other LSMs which provide a measure of + trust-based access control? + +A: + + In general, there's two other LSMs that can provide similar functionality: + IMA, and Loadpin. + + IMA and IPE are functionally very similar. The significant difference between + the two is the policy. [#devdoc]_ + + Loadpin and IPE differ fairly dramatically, as Loadpin only covers the IPE's + kernel read operations, whereas IPE is capable of controlling execution + on top of kernel read. The trust model is also different; Loadpin roots its + trust in the initial super-block, whereas trust in IPE is stemmed from kernel + itself (via ``SYSTEM_TRUSTED_KEYS``). + +----------- + +.. [#digest_cache_lsm] https://lore.kernel.org/lkml/20240415142436.2545003-1-roberto.sassu@huaweicloud.com/ + +.. [#interpreters] There is `some interest in solving this issue <https://lore.kernel.org/lkml/20220321161557.495388-1-mic@digikod.net/>`_. + +.. [#devdoc] Please see :doc:`the design docs </security/ipe>` for more on + this topic. + +.. [#switch_root] https://man7.org/linux/man-pages/man8/switch_root.8.html + +.. [#dmveritydigests] These hash algorithms are based on values accepted by + the Linux crypto API; IPE does not impose any + restrictions on the digest algorithm itself; + thus, this list may be out of date. + +.. [#fsveritydigest] These hash algorithms are based on values accepted by the + kernel's fsverity support; IPE does not impose any + restrictions on the digest algorithm itself; + thus, this list may be out of date. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index be010fec7654..0b400aa28482 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2350,6 +2350,18 @@ ipcmni_extend [KNL,EARLY] Extend the maximum number of unique System V IPC identifiers from 32,768 to 16,777,216. + ipe.enforce= [IPE] + Format: <bool> + Determine whether IPE starts in permissive (0) or + enforce (1) mode. The default is enforce. + + ipe.success_audit= + [IPE] + Format: <bool> + Start IPE with success auditing enabled, emitting + an audit event when a binary is allowed. The default + is 0. + irqaffinity= [SMP] Set the default irq affinity mask The argument is a cpu list, as described above. diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index 13e4b18e5dbb..0e2fac7a16da 100644 --- a/Documentation/filesystems/fsverity.rst +++ b/Documentation/filesystems/fsverity.rst @@ -86,6 +86,16 @@ authenticating fs-verity file hashes include: signature in their "security.ima" extended attribute, as controlled by the IMA policy. For more information, see the IMA documentation. +- Integrity Policy Enforcement (IPE). IPE supports enforcing access + control decisions based on immutable security properties of files, + including those protected by fs-verity's built-in signatures. + "IPE policy" specifically allows for the authorization of fs-verity + files using properties ``fsverity_digest`` for identifying + files by their verity digest, and ``fsverity_signature`` to authorize + files with a verified fs-verity's built-in signature. For + details on configuring IPE policies and understanding its operational + modes, please refer to :doc:`IPE admin guide </admin-guide/LSM/ipe>`. + - Trusted userspace code in combination with `Built-in signature verification`_. This approach should be used only with great care. @@ -457,7 +467,11 @@ Enabling this option adds the following: On success, the ioctl persists the signature alongside the Merkle tree. Then, any time the file is opened, the kernel verifies the file's actual digest against this signature, using the certificates - in the ".fs-verity" keyring. + in the ".fs-verity" keyring. This verification happens as long as the + file's signature exists, regardless of the state of the sysctl variable + "fs.verity.require_signatures" described in the next item. The IPE LSM + relies on this behavior to recognize and label fsverity files + that contain a verified built-in fsverity signature. 3. A new sysctl "fs.verity.require_signatures" is made available. When set to 1, the kernel requires that all verity files have a @@ -481,7 +495,7 @@ be carefully considered before using them: - Builtin signature verification does *not* make the kernel enforce that any files actually have fs-verity enabled. Thus, it is not a - complete authentication policy. Currently, if it is used, the only + complete authentication policy. Currently, if it is used, one way to complete the authentication policy is for trusted userspace code to explicitly check whether files have fs-verity enabled with a signature before they are accessed. (With @@ -490,6 +504,15 @@ be carefully considered before using them: could just store the signature alongside the file and verify it itself using a cryptographic library, instead of using this feature. +- Another approach is to utilize fs-verity builtin signature + verification in conjunction with the IPE LSM, which supports defining + a kernel-enforced, system-wide authentication policy that allows only + files with a verified fs-verity builtin signature to perform certain + operations, such as execution. Note that IPE doesn't require + fs.verity.require_signatures=1. + Please refer to :doc:`IPE admin guide </admin-guide/LSM/ipe>` for + more details. + - A file's builtin signature can only be set at the same time that fs-verity is being enabled on the file. Changing or deleting the builtin signature later requires re-creating the file. diff --git a/Documentation/security/index.rst b/Documentation/security/index.rst index 59f8fc106cb0..3e0a7114a862 100644 --- a/Documentation/security/index.rst +++ b/Documentation/security/index.rst @@ -19,3 +19,4 @@ Security Documentation digsig landlock secrets/index + ipe diff --git a/Documentation/security/ipe.rst b/Documentation/security/ipe.rst new file mode 100644 index 000000000000..4a7d953abcdc --- /dev/null +++ b/Documentation/security/ipe.rst @@ -0,0 +1,446 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Integrity Policy Enforcement (IPE) - Kernel Documentation +========================================================= + +.. NOTE:: + + This is documentation targeted at developers, instead of administrators. + If you're looking for documentation on the usage of IPE, please see + :doc:`IPE admin guide </admin-guide/LSM/ipe>`. + +Historical Motivation +--------------------- + +The original issue that prompted IPE's implementation was the creation +of a locked-down system. This system would be born-secure, and have +strong integrity guarantees over both the executable code, and specific +*data files* on the system, that were critical to its function. These +specific data files would not be readable unless they passed integrity +policy. A mandatory access control system would be present, and +as a result, xattrs would have to be protected. This lead to a selection +of what would provide the integrity claims. At the time, there were two +main mechanisms considered that could guarantee integrity for the system +with these requirements: + + 1. IMA + EVM Signatures + 2. DM-Verity + +Both options were carefully considered, however the choice to use DM-Verity +over IMA+EVM as the *integrity mechanism* in the original use case of IPE +was due to three main reasons: + + 1. Protection of additional attack vectors: + + * With IMA+EVM, without an encryption solution, the system is vulnerable + to offline attack against the aforementioned specific data files. + + Unlike executables, read operations (like those on the protected data + files), cannot be enforced to be globally integrity verified. This means + there must be some form of selector to determine whether a read should + enforce the integrity policy, or it should not. + + At the time, this was done with mandatory access control labels. An IMA + policy would indicate what labels required integrity verification, which + presented an issue: EVM would protect the label, but if an attacker could + modify filesystem offline, the attacker could wipe all the xattrs - + including the SELinux labels that would be used to determine whether the + file should be subject to integrity policy. + + With DM-Verity, as the xattrs are saved as part of the Merkel tree, if + offline mount occurs against the filesystem protected by dm-verity, the + checksum no longer matches and the file fails to be read. + + * As userspace binaries are paged in Linux, dm-verity also offers the + additional protection against a hostile block device. In such an attack, + the block device reports the appropriate content for the IMA hash + initially, passing the required integrity check. Then, on the page fault + that accesses the real data, will report the attacker's payload. Since + dm-verity will check the data when the page fault occurs (and the disk + access), this attack is mitigated. + + 2. Performance: + + * dm-verity provides integrity verification on demand as blocks are + read versus requiring the entire file being read into memory for + validation. + + 3. Simplicity of signing: + + * No need for two signatures (IMA, then EVM): one signature covers + an entire block device. + * Signatures can be stored externally to the filesystem metadata. + * The signature supports an x.509-based signing infrastructure. + +The next step was to choose a *policy* to enforce the integrity mechanism. +The minimum requirements for the policy were: + + 1. The policy itself must be integrity verified (preventing trivial + attack against it). + 2. The policy itself must be resistant to rollback attacks. + 3. The policy enforcement must have a permissive-like mode. + 4. The policy must be able to be updated, in its entirety, without + a reboot. + 5. Policy updates must be atomic. + 6. The policy must support *revocations* of previously authored + components. + 7. The policy must be auditable, at any point-of-time. + +IMA, as the only integrity policy mechanism at the time, was +considered against these list of requirements, and did not fulfill +all of the minimum requirements. Extending IMA to cover these +requirements was considered, but ultimately discarded for a +two reasons: + + 1. Regression risk; many of these changes would result in + dramatic code changes to IMA, which is already present in the + kernel, and therefore might impact users. + + 2. IMA was used in the system for measurement and attestation; + separation of measurement policy from local integrity policy + enforcement was considered favorable. + +Due to these reasons, it was decided that a new LSM should be created, +whose responsibility would be only the local integrity policy enforcement. + +Role and Scope +-------------- + +IPE, as its name implies, is fundamentally an integrity policy enforcement +solution; IPE does not mandate how integrity is provided, but instead +leaves that decision to the system administrator to set the security bar, +via the mechanisms that they select that suit their individual needs. +There are several different integrity solutions that provide a different +level of security guarantees; and IPE allows sysadmins to express policy for +theoretically all of them. + +IPE does not have an inherent mechanism to ensure integrity on its own. +Instead, there are more effective layers available for building systems that +can guarantee integrity. It's important to note that the mechanism for proving +integrity is independent of the policy for enforcing that integrity claim. + +Therefore, IPE was designed around: + + 1. Easy integrations with integrity providers. + 2. Ease of use for platform administrators/sysadmins. + +Design Rationale: +----------------- + +IPE was designed after evaluating existing integrity policy solutions +in other operating systems and environments. In this survey of other +implementations, there were a few pitfalls identified: + + 1. Policies were not readable by humans, usually requiring a binary + intermediary format. + 2. A single, non-customizable action was implicitly taken as a default. + 3. Debugging the policy required manual steps to determine what rule was violated. + 4. Authoring a policy required an in-depth knowledge of the larger system, + or operating system. + +IPE attempts to avoid all of these pitfalls. + +Policy +~~~~~~ + +Plain Text +^^^^^^^^^^ + +IPE's policy is plain-text. This introduces slightly larger policy files than +other LSMs, but solves two major problems that occurs with some integrity policy +solutions on other platforms. + +The first issue is one of code maintenance and duplication. To author policies, +the policy has to be some form of string representation (be it structured, +through XML, JSON, YAML, etcetera), to allow the policy author to understand +what is being written. In a hypothetical binary policy design, a serializer +is necessary to write the policy from the human readable form, to the binary +form, and a deserializer is needed to interpret the binary form into a data +structure in the kernel. + +Eventually, another deserializer will be needed to transform the binary from +back into the human-readable form with as much information preserved. This is because a +user of this access control system will have to keep a lookup table of a checksum +and the original file itself to try to understand what policies have been deployed +on this system and what policies have not. For a single user, this may be alright, +as old policies can be discarded almost immediately after the update takes hold. +For users that manage computer fleets in the thousands, if not hundreds of thousands, +with multiple different operating systems, and multiple different operational needs, +this quickly becomes an issue, as stale policies from years ago may be present, +quickly resulting in the need to recover the policy or fund extensive infrastructure +to track what each policy contains. + +With now three separate serializer/deserializers, maintenance becomes costly. If the +policy avoids the binary format, there is only one required serializer: from the +human-readable form to the data structure in kernel, saving on code maintenance, +and retaining operability. + +The second issue with a binary format is one of transparency. As IPE controls +access based on the trust of the system's resources, it's policy must also be +trusted to be changed. This is done through signatures, resulting in needing +signing as a process. Signing, as a process, is typically done with a +high security bar, as anything signed can be used to attack integrity +enforcement systems. It is also important that, when signing something, that +the signer is aware of what they are signing. A binary policy can cause +obfuscation of that fact; what signers see is an opaque binary blob. A +plain-text policy, on the other hand, the signers see the actual policy +submitted for signing. + +Boot Policy +~~~~~~~~~~~ + +IPE, if configured appropriately, is able to enforce a policy as soon as a +kernel is booted and usermode starts. That implies some level of storage +of the policy to apply the minute usermode starts. Generally, that storage +can be handled in one of three ways: + + 1. The policy file(s) live on disk and the kernel loads the policy prior + to an code path that would result in an enforcement decision. + 2. The policy file(s) are passed by the bootloader to the kernel, who + parses the policy. + 3. There is a policy file that is compiled into the kernel that is + parsed and enforced on initialization. + +The first option has problems: the kernel reading files from userspace +is typically discouraged and very uncommon in the kernel. + +The second option also has problems: Linux supports a variety of bootloaders +across its entire ecosystem - every bootloader would have to support this +new methodology or there must be an independent source. It would likely +result in more drastic changes to the kernel startup than necessary. + +The third option is the best but it's important to be aware that the policy +will take disk space against the kernel it's compiled in. It's important to +keep this policy generalized enough that userspace can load a new, more +complicated policy, but restrictive enough that it will not overauthorize +and cause security issues. + +The initramfs provides a way that this bootup path can be established. The +kernel starts with a minimal policy, that trusts the initramfs only. Inside +the initramfs, when the real rootfs is mounted, but not yet transferred to, +it deploys and activates a policy that trusts the new root filesystem. +This prevents overauthorization at any step, and keeps the kernel policy +to a minimal size. + +Startup +^^^^^^^ + +Not every system, however starts with an initramfs, so the startup policy +compiled into the kernel will need some flexibility to express how trust +is established for the next phase of the bootup. To this end, if we just +make the compiled-in policy a full IPE policy, it allows system builders +to express the first stage bootup requirements appropriately. + +Updatable, Rebootless Policy +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +As requirements change over time (vulnerabilities are found in previously +trusted applications, keys roll, etcetera). Updating a kernel to change the +meet those security goals is not always a suitable option, as updates are not +always risk-free, and blocking a security update leaves systems vulnerable. +This means IPE requires a policy that can be completely updated (allowing +revocations of existing policy) from a source external to the kernel (allowing +policies to be updated without updating the kernel). + +Additionally, since the kernel is stateless between invocations, and reading +policy files off the disk from kernel space is a bad idea(tm), then the +policy updates have to be done rebootlessly. + +To allow an update from an external source, it could be potentially malicious, +so this policy needs to have a way to be identified as trusted. This is +done via a signature chained to a trust source in the kernel. Arbitrarily, +this is the ``SYSTEM_TRUSTED_KEYRING``, a keyring that is initially +populated at kernel compile-time, as this matches the expectation that the +author of the compiled-in policy described above is the same entity that can +deploy policy updates. + +Anti-Rollback / Anti-Replay +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Over time, vulnerabilities are found and trusted resources may not be +trusted anymore. IPE's policy has no exception to this. There can be +instances where a mistaken policy author deploys an insecure policy, +before correcting it with a secure policy. + +Assuming that as soon as the insecure policy is signed, and an attacker +acquires the insecure policy, IPE needs a way to prevent rollback +from the secure policy update to the insecure policy update. + +Initially, IPE's policy can have a policy_version that states the +minimum required version across all policies that can be active on +the system. This will prevent rollback while the system is live. + +.. WARNING:: + + However, since the kernel is stateless across boots, this policy + version will be reset to 0.0.0 on the next boot. System builders + need to be aware of this, and ensure the new secure policies are + deployed ASAP after a boot to ensure that the window of + opportunity is minimal for an attacker to deploy the insecure policy. + +Implicit Actions: +~~~~~~~~~~~~~~~~~ + +The issue of implicit actions only becomes visible when you consider +a mixed level of security bars across multiple operations in a system. +For example, consider a system that has strong integrity guarantees +over both the executable code, and specific *data files* on the system, +that were critical to its function. In this system, three types of policies +are possible: + + 1. A policy in which failure to match any rules in the policy results + in the action being denied. + 2. A policy in which failure to match any rules in the policy results + in the action being allowed. + 3. A policy in which the action taken when no rules are matched is + specified by the policy author. + +The first option could make a policy like this:: + + op=EXECUTE integrity_verified=YES action=ALLOW + +In the example system, this works well for the executables, as all +executables should have integrity guarantees, without exception. The +issue becomes with the second requirement about specific data files. +This would result in a policy like this (assuming each line is +evaluated in order):: + + op=EXECUTE integrity_verified=YES action=ALLOW + + op=READ integrity_verified=NO label=critical_t action=DENY + op=READ action=ALLOW + +This is somewhat clear if you read the docs, understand the policy +is executed in order and that the default is a denial; however, the +last line effectively changes that default to an ALLOW. This is +required, because in a realistic system, there are some unverified +reads (imagine appending to a log file). + +The second option, matching no rules results in an allow, is clearer +for the specific data files:: + + op=READ integrity_verified=NO label=critical_t action=DENY + +And, like the first option, falls short with the execution scenario, +effectively needing to override the default:: + + op=EXECUTE integrity_verified=YES action=ALLOW + op=EXECUTE action=DENY + + op=READ integrity_verified=NO label=critical_t action=DENY + +This leaves the third option. Instead of making users be clever +and override the default with an empty rule, force the end-user +to consider what the appropriate default should be for their +scenario and explicitly state it:: + + DEFAULT op=EXECUTE action=DENY + op=EXECUTE integrity_verified=YES action=ALLOW + + DEFAULT op=READ action=ALLOW + op=READ integrity_verified=NO label=critical_t action=DENY + +Policy Debugging: +~~~~~~~~~~~~~~~~~ + +When developing a policy, it is useful to know what line of the policy +is being violated to reduce debugging costs; narrowing the scope of the +investigation to the exact line that resulted in the action. Some integrity +policy systems do not provide this information, instead providing the +information that was used in the evaluation. This then requires a correlation +with the policy to evaluate what went wrong. + +Instead, IPE just emits the rule that was matched. This limits the scope +of the investigation to the exact policy line (in the case of a specific +rule), or the section (in the case of a DEFAULT). This decreases iteration +and investigation times when policy failures are observed while evaluating +policies. + +IPE's policy engine is also designed in a way that it makes it obvious to +a human of how to investigate a policy failure. Each line is evaluated in +the sequence that is written, so the algorithm is very simple to follow +for humans to recreate the steps and could have caused the failure. In other +surveyed systems, optimizations occur (sorting rules, for instance) when loading +the policy. In those systems, it requires multiple steps to debug, and the +algorithm may not always be clear to the end-user without reading the code first. + +Simplified Policy: +~~~~~~~~~~~~~~~~~~ + +Finally, IPE's policy is designed for sysadmins, not kernel developers. Instead +of covering individual LSM hooks (or syscalls), IPE covers operations. This means +instead of sysadmins needing to know that the syscalls ``mmap``, ``mprotect``, +``execve``, and ``uselib`` must have rules protecting them, they must simple know +that they want to restrict code execution. This limits the amount of bypasses that +could occur due to a lack of knowledge of the underlying system; whereas the +maintainers of IPE, being kernel developers can make the correct choice to determine +whether something maps to these operations, and under what conditions. + +Implementation Notes +-------------------- + +Anonymous Memory +~~~~~~~~~~~~~~~~ + +Anonymous memory isn't treated any differently from any other access in IPE. +When anonymous memory is mapped with ``+X``, it still comes into the ``file_mmap`` +or ``file_mprotect`` hook, but with a ``NULL`` file object. This is submitted to +the evaluation, like any other file. However, all current trust properties will +evaluate to false, as they are all file-based and the operation is not +associated with a file. + +.. WARNING:: + + This also occurs with the ``kernel_load_data`` hook, when the kernel is + loading data from a userspace buffer that is not backed by a file. In this + scenario all current trust properties will also evaluate to false. + +Securityfs Interface +~~~~~~~~~~~~~~~~~~~~ + +The per-policy securityfs tree is somewhat unique. For example, for +a standard securityfs policy tree:: + + MyPolicy + |- active + |- delete + |- name + |- pkcs7 + |- policy + |- update + |- version + +The policy is stored in the ``->i_private`` data of the MyPolicy inode. + +Tests +----- + +IPE has KUnit Tests for the policy parser. Recommended kunitconfig:: + + CONFIG_KUNIT=y + CONFIG_SECURITY=y + CONFIG_SECURITYFS=y + CONFIG_PKCS7_MESSAGE_PARSER=y + CONFIG_SYSTEM_DATA_VERIFICATION=y + CONFIG_FS_VERITY=y + CONFIG_FS_VERITY_BUILTIN_SIGNATURES=y + CONFIG_BLOCK=y + CONFIG_MD=y + CONFIG_BLK_DEV_DM=y + CONFIG_DM_VERITY=y + CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG=y + CONFIG_NET=y + CONFIG_AUDIT=y + CONFIG_AUDITSYSCALL=y + CONFIG_BLK_DEV_INITRD=y + + CONFIG_SECURITY_IPE=y + CONFIG_IPE_PROP_DM_VERITY=y + CONFIG_IPE_PROP_DM_VERITY_SIGNATURE=y + CONFIG_IPE_PROP_FS_VERITY=y + CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG=y + CONFIG_SECURITY_IPE_KUNIT_TEST=y + +In addition, IPE has a python based integration +`test suite <https://github.com/microsoft/ipe/tree/test-suite>`_ that +can test both user interfaces and enforcement functionalities. diff --git a/MAINTAINERS b/MAINTAINERS index 7081f93bdb9a..5432239f3c5d 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -11166,6 +11166,16 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git F: security/integrity/ F: security/integrity/ima/ +INTEGRITY POLICY ENFORCEMENT (IPE) +M: Fan Wu <wufan@linux.microsoft.com> +L: linux-security-module@vger.kernel.org +S: Supported +T: git https://github.com/microsoft/ipe.git +F: Documentation/admin-guide/LSM/ipe.rst +F: Documentation/security/ipe.rst +F: scripts/ipe/ +F: security/ipe/ + INTEL 810/815 FRAMEBUFFER DRIVER M: Antonino Daplas <adaplas@gmail.com> L: linux-fbdev@vger.kernel.org diff --git a/block/bdev.c b/block/bdev.c index c5507b6f63b8..33f9c4605e3a 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -24,6 +24,7 @@ #include <linux/pseudo_fs.h> #include <linux/uio.h> #include <linux/namei.h> +#include <linux/security.h> #include <linux/part_stat.h> #include <linux/uaccess.h> #include <linux/stat.h> @@ -324,6 +325,11 @@ static struct inode *bdev_alloc_inode(struct super_block *sb) if (!ei) return NULL; memset(&ei->bdev, 0, sizeof(ei->bdev)); + + if (security_bdev_alloc(&ei->bdev)) { + kmem_cache_free(bdev_cachep, ei); + return NULL; + } return &ei->vfs_inode; } @@ -333,6 +339,7 @@ static void bdev_free_inode(struct inode *inode) free_percpu(bdev->bd_stats); kfree(bdev->bd_meta_info); + security_bdev_free(bdev); if (!bdev_is_partition(bdev)) { if (bdev->bd_disk && bdev->bd_disk->bdi) diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c index cf659c8feb29..24ba9a10444c 100644 --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -22,6 +22,7 @@ #include <linux/scatterlist.h> #include <linux/string.h> #include <linux/jump_label.h> +#include <linux/security.h> #define DM_MSG_PREFIX "verity" @@ -930,6 +931,41 @@ static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) limits->dma_alignment = limits->logical_block_size - 1; } +#ifdef CONFIG_SECURITY + +static int verity_init_sig(struct dm_verity *v, const void *sig, + size_t sig_size) +{ + v->sig_size = sig_size; + + if (sig) { + v->root_digest_sig = kmemdup(sig, v->sig_size, GFP_KERNEL); + if (!v->root_digest_sig) + return -ENOMEM; + } + + return 0; +} + +static void verity_free_sig(struct dm_verity *v) +{ + kfree(v->root_digest_sig); +} + +#else + +static inline int verity_init_sig(struct dm_verity *v, const void *sig, + size_t sig_size) +{ + return 0; +} + +static inline void verity_free_sig(struct dm_verity *v) +{ +} + +#endif /* CONFIG_SECURITY */ + static void verity_dtr(struct dm_target *ti) { struct dm_verity *v = ti->private; @@ -949,6 +985,7 @@ static void verity_dtr(struct dm_target *ti) kfree(v->initial_hashstate); kfree(v->root_digest); kfree(v->zero_digest); + verity_free_sig(v); if (v->ahash_tfm) { static_branch_dec(&ahash_enabled); @@ -1418,6 +1455,13 @@ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv) ti->error = "Root hash verification failed"; goto bad; } + + r = verity_init_sig(v, verify_args.sig, verify_args.sig_size); + if (r < 0) { + ti->error = "Cannot allocate root digest signature"; + goto bad; + } + v->hash_per_block_bits = __fls((1 << v->hash_dev_block_bits) / v->digest_size); @@ -1559,8 +1603,79 @@ int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, unsigned i return 0; } +#ifdef CONFIG_SECURITY + +#ifdef CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG + +static int verity_security_set_signature(struct block_device *bdev, + struct dm_verity *v) +{ + /* + * if the dm-verity target is unsigned, v->root_digest_sig will + * be NULL, and the hook call is still required to let LSMs mark + * the device as unsigned. This information is crucial for LSMs to + * block operations such as execution on unsigned files + */ + return security_bdev_setintegrity(bdev, + LSM_INT_DMVERITY_SIG_VALID, + v->root_digest_sig, + v->sig_size); +} + +#else + +static inline int verity_security_set_signature(struct block_device *bdev, + struct dm_verity *v) +{ + return 0; +} + +#endif /* CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG */ + +/* + * Expose verity target's root hash and signature data to LSMs before resume. + * + * Returns 0 on success, or -ENOMEM if the system is out of memory. + */ +static int verity_preresume(struct dm_target *ti) +{ + struct block_device *bdev; + struct dm_verity_digest root_digest; + struct dm_verity *v; + int r; + + v = ti->private; + bdev = dm_disk(dm_table_get_md(ti->table))->part0; + root_digest.digest = v->root_digest; + root_digest.digest_len = v->digest_size; + if (static_branch_unlikely(&ahash_enabled) && !v->shash_tfm) + root_digest.alg = crypto_ahash_alg_name(v->ahash_tfm); + else + root_digest.alg = crypto_shash_alg_name(v->shash_tfm); + + r = security_bdev_setintegrity(bdev, LSM_INT_DMVERITY_ROOTHASH, &root_digest, + sizeof(root_digest)); + if (r) + return r; + + r = verity_security_set_signature(bdev, v); + if (r) + goto bad; + + return 0; + +bad: + + security_bdev_setintegrity(bdev, LSM_INT_DMVERITY_ROOTHASH, NULL, 0); + + return r; +} + +#endif /* CONFIG_SECURITY */ + static struct target_type verity_target = { .name = "verity", +/* Note: the LSMs depend on the singleton and immutable features */ .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE, .version = {1, 10, 0}, .module = THIS_MODULE, @@ -1571,6 +1686,9 @@ static struct target_type verity_target = { .prepare_ioctl = verity_prepare_ioctl, .iterate_devices = verity_iterate_devices, .io_hints = verity_io_hints, +#ifdef CONFIG_SECURITY + .preresume = verity_preresume, +#endif /* CONFIG_SECURITY */ }; module_dm(verity); diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h index aac3a1b1d94a..754e70bb5fe0 100644 --- a/drivers/md/dm-verity.h +++ b/drivers/md/dm-verity.h @@ -45,6 +45,10 @@ struct dm_verity { u8 *salt; /* salt: its size is salt_size */ u8 *initial_hashstate; /* salted initial state, if shash_tfm is set */ u8 *zero_digest; /* digest for a zero block */ +#ifdef CONFIG_SECURITY + u8 *root_digest_sig; /* signature of the root digest */ + unsigned int sig_size; /* root digest signature size */ +#endif /* CONFIG_SECURITY */ unsigned int salt_size; sector_t data_start; /* data offset in 512-byte sectors */ sector_t hash_start; /* hash start in blocks */ diff --git a/fs/fcntl.c b/fs/fcntl.c index f6fde75a3bd5..081e5e3d89ea 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -125,8 +125,8 @@ void file_f_owner_release(struct file *file) } } -static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, - int force) +void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, + int force) { struct fown_struct *f_owner; @@ -142,19 +142,13 @@ static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, if (pid) { const struct cred *cred = current_cred(); + security_file_set_fowner(filp); f_owner->uid = cred->uid; f_owner->euid = cred->euid; } } write_unlock_irq(&f_owner->lock); } - -void __f_setown(struct file *filp, struct pid *pid, enum pid_type type, - int force) -{ - security_file_set_fowner(filp); - f_modown(filp, pid, type, force); -} EXPORT_SYMBOL(__f_setown); int f_setown(struct file *filp, int who, int force) @@ -196,7 +190,7 @@ EXPORT_SYMBOL(f_setown); void f_delown(struct file *filp) { - f_modown(filp, NULL, PIDTYPE_TGID, 1); + __f_setown(filp, NULL, PIDTYPE_TGID, 1); } pid_t f_getown(struct file *filp) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index a5ef2005a2cc..337a5be99ac9 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -115,12 +115,12 @@ int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct de continue; error = security_inode_copy_up_xattr(old, name); - if (error < 0 && error != -EOPNOTSUPP) - break; - if (error == 1) { + if (error == -ECANCELED) { error = 0; continue; /* Discard */ } + if (error < 0 && error != -EOPNOTSUPP) + break; if (is_posix_acl_xattr(name)) { error = ovl_copy_acl(OVL_FS(sb), oldpath, new, name); diff --git a/fs/verity/signature.c b/fs/verity/signature.c index 90c07573dd77..0302a4e506ec 100644 --- a/fs/verity/signature.c +++ b/fs/verity/signature.c @@ -17,6 +17,7 @@ #include <linux/cred.h> #include <linux/key.h> +#include <linux/security.h> #include <linux/slab.h> #include <linux/verification.h> @@ -41,7 +42,11 @@ static struct key *fsverity_keyring; * @sig_size: size of signature in bytes, or 0 if no signature * * If the file includes a signature of its fs-verity file digest, verify it - * against the certificates in the fs-verity keyring. + * against the certificates in the fs-verity keyring. Note that signatures + * are verified regardless of the state of the 'fsverity_require_signatures' + * variable and the LSM subsystem relies on this behavior to help enforce + * file integrity policies. Please discuss changes with the LSM list + * (thank you!). * * Return: 0 on success (signature valid or not required); -errno on failure */ @@ -106,6 +111,17 @@ int fsverity_verify_signature(const struct fsverity_info *vi, return err; } + err = security_inode_setintegrity(inode, + LSM_INT_FSVERITY_BUILTINSIG_VALID, + signature, + sig_size); + + if (err) { + fsverity_err(inode, "Error %d exposing file signature to LSMs", + err); + return err; + } + return 0; } diff --git a/include/linux/args.h b/include/linux/args.h index 8ff60a54eb7d..2e8e65d975c7 100644 --- a/include/linux/args.h +++ b/include/linux/args.h @@ -17,9 +17,9 @@ * that as _n. */ -/* This counts to 12. Any more, it will return 13th argument. */ -#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n -#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) +/* This counts to 15. Any more, it will return 16th argument. */ +#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _n, X...) _n +#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) /* Concatenate two parameters, but allow them to be expanded beforehand. */ #define __CONCAT(a, b) a ## b diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 36ed96133217..413ebdff974b 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -71,6 +71,9 @@ struct block_device { struct partition_meta_info *bd_meta_info; int bd_writers; +#ifdef CONFIG_SECURITY + void *bd_security; +#endif /* * keep this out-of-line as it's both big and not needed in the fast * path diff --git a/include/linux/lsm_count.h b/include/linux/lsm_count.h new file mode 100644 index 000000000000..16eb49761b25 --- /dev/null +++ b/include/linux/lsm_count.h @@ -0,0 +1,135 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright (C) 2023 Google LLC. + */ + +#ifndef __LINUX_LSM_COUNT_H +#define __LINUX_LSM_COUNT_H + +#include <linux/args.h> + +#ifdef CONFIG_SECURITY + +/* + * Macros to count the number of LSMs enabled in the kernel at compile time. + */ + +/* + * Capabilities is enabled when CONFIG_SECURITY is enabled. + */ +#if IS_ENABLED(CONFIG_SECURITY) +#define CAPABILITIES_ENABLED 1, +#else +#define CAPABILITIES_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_SELINUX) +#define SELINUX_ENABLED 1, +#else +#define SELINUX_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_SMACK) +#define SMACK_ENABLED 1, +#else +#define SMACK_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_APPARMOR) +#define APPARMOR_ENABLED 1, +#else +#define APPARMOR_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_TOMOYO) +#define TOMOYO_ENABLED 1, +#else +#define TOMOYO_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_YAMA) +#define YAMA_ENABLED 1, +#else +#define YAMA_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_LOADPIN) +#define LOADPIN_ENABLED 1, +#else +#define LOADPIN_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) +#define LOCKDOWN_ENABLED 1, +#else +#define LOCKDOWN_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_SAFESETID) +#define SAFESETID_ENABLED 1, +#else +#define SAFESETID_ENABLED +#endif + +#if IS_ENABLED(CONFIG_BPF_LSM) +#define BPF_LSM_ENABLED 1, +#else +#define BPF_LSM_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_LANDLOCK) +#define LANDLOCK_ENABLED 1, +#else +#define LANDLOCK_ENABLED +#endif + +#if IS_ENABLED(CONFIG_IMA) +#define IMA_ENABLED 1, +#else +#define IMA_ENABLED +#endif + +#if IS_ENABLED(CONFIG_EVM) +#define EVM_ENABLED 1, +#else +#define EVM_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_IPE) +#define IPE_ENABLED 1, +#else +#define IPE_ENABLED +#endif + +/* + * There is a trailing comma that we need to be accounted for. This is done by + * using a skipped argument in __COUNT_LSMS + */ +#define __COUNT_LSMS(skipped_arg, args...) COUNT_ARGS(args...) +#define COUNT_LSMS(args...) __COUNT_LSMS(args) + +#define MAX_LSM_COUNT \ + COUNT_LSMS( \ + CAPABILITIES_ENABLED \ + SELINUX_ENABLED \ + SMACK_ENABLED \ + APPARMOR_ENABLED \ + TOMOYO_ENABLED \ + YAMA_ENABLED \ + LOADPIN_ENABLED \ + LOCKDOWN_ENABLED \ + SAFESETID_ENABLED \ + BPF_LSM_ENABLED \ + LANDLOCK_ENABLED \ + IMA_ENABLED \ + EVM_ENABLED \ + IPE_ENABLED) + +#else + +#define MAX_LSM_COUNT 0 + +#endif /* CONFIG_SECURITY */ + +#endif /* __LINUX_LSM_COUNT_H */ diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 855db460e08b..1d59513bf230 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -48,7 +48,7 @@ LSM_HOOK(int, 0, quota_on, struct dentry *dentry) LSM_HOOK(int, 0, syslog, int type) LSM_HOOK(int, 0, settime, const struct timespec64 *ts, const struct timezone *tz) -LSM_HOOK(int, 1, vm_enough_memory, struct mm_struct *mm, long pages) +LSM_HOOK(int, 0, vm_enough_memory, struct mm_struct *mm, long pages) LSM_HOOK(int, 0, bprm_creds_for_exec, struct linux_binprm *bprm) LSM_HOOK(int, 0, bprm_creds_from_file, struct linux_binprm *bprm, const struct file *file) LSM_HOOK(int, 0, bprm_check_security, struct linux_binprm *bprm) @@ -114,6 +114,7 @@ LSM_HOOK(int, 0, path_notify, const struct path *path, u64 mask, unsigned int obj_type) LSM_HOOK(int, 0, inode_alloc_security, struct inode *inode) LSM_HOOK(void, LSM_RET_VOID, inode_free_security, struct inode *inode) +LSM_HOOK(void, LSM_RET_VOID, inode_free_security_rcu, void *inode_security) LSM_HOOK(int, -EOPNOTSUPP, inode_init_security, struct inode *inode, struct inode *dir, const struct qstr *qstr, struct xattr *xattrs, int *xattr_count) @@ -179,6 +180,8 @@ LSM_HOOK(void, LSM_RET_VOID, inode_getsecid, struct inode *inode, u32 *secid) LSM_HOOK(int, 0, inode_copy_up, struct dentry *src, struct cred **new) LSM_HOOK(int, -EOPNOTSUPP, inode_copy_up_xattr, struct dentry *src, const char *name) +LSM_HOOK(int, 0, inode_setintegrity, const struct inode *inode, + enum lsm_integrity_type type, const void *value, size_t size) LSM_HOOK(int, 0, kernfs_init_security, struct kernfs_node *kn_dir, struct kernfs_node *kn) LSM_HOOK(int, 0, file_permission, struct file *file, int mask) @@ -353,8 +356,7 @@ LSM_HOOK(void, LSM_RET_VOID, secmark_refcount_inc, void) LSM_HOOK(void, LSM_RET_VOID, secmark_refcount_dec, void) LSM_HOOK(void, LSM_RET_VOID, req_classify_flow, const struct request_sock *req, struct flowi_common *flic) -LSM_HOOK(int, 0, tun_dev_alloc_security, void **security) -LSM_HOOK(void, LSM_RET_VOID, tun_dev_free_security, void *security) +LSM_HOOK(int, 0, tun_dev_alloc_security, void *security) LSM_HOOK(int, 0, tun_dev_create, void) LSM_HOOK(int, 0, tun_dev_attach_queue, void *security) LSM_HOOK(int, 0, tun_dev_attach, struct sock *sk, void *security) @@ -374,8 +376,7 @@ LSM_HOOK(int, 0, mptcp_add_subflow, struct sock *sk, struct sock *ssk) LSM_HOOK(int, 0, ib_pkey_access, void *sec, u64 subnet_prefix, u16 pkey) LSM_HOOK(int, 0, ib_endport_manage_subnet, void *sec, const char *dev_name, u8 port_num) -LSM_HOOK(int, 0, ib_alloc_security, void **sec) -LSM_HOOK(void, LSM_RET_VOID, ib_free_security, void *sec) +LSM_HOOK(int, 0, ib_alloc_security, void *sec) #endif /* CONFIG_SECURITY_INFINIBAND */ #ifdef CONFIG_SECURITY_NETWORK_XFRM @@ -403,7 +404,6 @@ LSM_HOOK(int, 0, xfrm_decode_session, struct sk_buff *skb, u32 *secid, #ifdef CONFIG_KEYS LSM_HOOK(int, 0, key_alloc, struct key *key, const struct cred *cred, unsigned long flags) -LSM_HOOK(void, LSM_RET_VOID, key_free, struct key *key) LSM_HOOK(int, 0, key_permission, key_ref_t key_ref, const struct cred *cred, enum key_need_perm need_perm) LSM_HOOK(int, 0, key_getsecurity, struct key *key, char **buffer) @@ -442,7 +442,6 @@ LSM_HOOK(int, 0, locked_down, enum lockdown_reason what) #ifdef CONFIG_PERF_EVENTS LSM_HOOK(int, 0, perf_event_open, struct perf_event_attr *attr, int type) LSM_HOOK(int, 0, perf_event_alloc, struct perf_event *event) -LSM_HOOK(void, LSM_RET_VOID, perf_event_free, struct perf_event *event) LSM_HOOK(int, 0, perf_event_read, struct perf_event *event) LSM_HOOK(int, 0, perf_event_write, struct perf_event *event) #endif /* CONFIG_PERF_EVENTS */ @@ -452,3 +451,10 @@ LSM_HOOK(int, 0, uring_override_creds, const struct cred *new) LSM_HOOK(int, 0, uring_sqpoll, void) LSM_HOOK(int, 0, uring_cmd, struct io_uring_cmd *ioucmd) #endif /* CONFIG_IO_URING */ + +LSM_HOOK(void, LSM_RET_VOID, initramfs_populated, void) + +LSM_HOOK(int, 0, bdev_alloc_security, struct block_device *bdev) +LSM_HOOK(void, LSM_RET_VOID, bdev_free_security, struct block_device *bdev) +LSM_HOOK(int, 0, bdev_setintegrity, struct block_device *bdev, + enum lsm_integrity_type type, const void *value, size_t size) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index a2ade0ffe9e7..090d1d3e19fe 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -30,19 +30,47 @@ #include <linux/init.h> #include <linux/rculist.h> #include <linux/xattr.h> +#include <linux/static_call.h> +#include <linux/unroll.h> +#include <linux/jump_label.h> +#include <linux/lsm_count.h> union security_list_options { #define LSM_HOOK(RET, DEFAULT, NAME, ...) RET (*NAME)(__VA_ARGS__); #include "lsm_hook_defs.h" #undef LSM_HOOK + void *lsm_func_addr; }; -struct security_hook_heads { - #define LSM_HOOK(RET, DEFAULT, NAME, ...) struct hlist_head NAME; - #include "lsm_hook_defs.h" - #undef LSM_HOOK +/* + * @key: static call key as defined by STATIC_CALL_KEY + * @trampoline: static call trampoline as defined by STATIC_CALL_TRAMP + * @hl: The security_hook_list as initialized by the owning LSM. + * @active: Enabled when the static call has an LSM hook associated. + */ +struct lsm_static_call { + struct static_call_key *key; + void *trampoline; + struct security_hook_list *hl; + /* this needs to be true or false based on what the key defaults to */ + struct static_key_false *active; } __randomize_layout; +/* + * Table of the static calls for each LSM hook. + * Once the LSMs are initialized, their callbacks will be copied to these + * tables such that the calls are filled backwards (from last to first). + * This way, we can jump directly to the first used static call, and execute + * all of them after. This essentially makes the entry point + * dynamic to adapt the number of static calls to the number of callbacks. + */ +struct lsm_static_calls_table { + #define LSM_HOOK(RET, DEFAULT, NAME, ...) \ + struct lsm_static_call NAME[MAX_LSM_COUNT]; + #include <linux/lsm_hook_defs.h> + #undef LSM_HOOK +} __packed __randomize_layout; + /** * struct lsm_id - Identify a Linux Security Module. * @lsm: name of the LSM, must be approved by the LSM maintainers @@ -51,53 +79,45 @@ struct security_hook_heads { * Contains the information that identifies the LSM. */ struct lsm_id { - const char *name; - u64 id; + const char *name; + u64 id; }; /* * Security module hook list structure. * For use with generic list macros for common operations. + * + * struct security_hook_list - Contents of a cacheable, mappable object. + * @scalls: The beginning of the array of static calls assigned to this hook. + * @hook: The callback for the hook. + * @lsm: The name of the lsm that owns this hook. */ struct security_hook_list { - struct hlist_node list; - struct hlist_head *head; - union security_list_options hook; - const struct lsm_id *lsmid; + struct lsm_static_call *scalls; + union security_list_options hook; + const struct lsm_id *lsmid; } __randomize_layout; /* * Security blob size or offset data. */ struct lsm_blob_sizes { - int lbs_cred; - int lbs_file; - int lbs_inode; - int lbs_superblock; - int lbs_ipc; - int lbs_msg_msg; - int lbs_task; - int lbs_xattr_count; /* number of xattr slots in new_xattrs array */ + int lbs_cred; + int lbs_file; + int lbs_ib; + int lbs_inode; + int lbs_sock; + int lbs_superblock; + int lbs_ipc; + int lbs_key; + int lbs_msg_msg; + int lbs_perf_event; + int lbs_task; + int lbs_xattr_count; /* number of xattr slots in new_xattrs array */ + int lbs_tun_dev; + int lbs_bdev; }; -/** - * lsm_get_xattr_slot - Return the next available slot and increment the index - * @xattrs: array storing LSM-provided xattrs - * @xattr_count: number of already stored xattrs (updated) - * - * Retrieve the first available slot in the @xattrs array to fill with an xattr, - * and increment @xattr_count. - * - * Return: The slot to fill in @xattrs if non-NULL, NULL otherwise. - */ -static inline struct xattr *lsm_get_xattr_slot(struct xattr *xattrs, - int *xattr_count) -{ - if (unlikely(!xattrs)) - return NULL; - return &xattrs[(*xattr_count)++]; -} - /* * LSM_RET_VOID is used as the default value in LSM_HOOK definitions for void * LSM hooks (in include/linux/lsm_hook_defs.h). @@ -110,11 +130,11 @@ static inline struct xattr *lsm_get_xattr_slot(struct xattr *xattrs, * care of the common case and reduces the amount of * text involved. */ -#define LSM_HOOK_INIT(HEAD, HOOK) \ - { .head = &security_hook_heads.HEAD, .hook = { .HEAD = HOOK } } - -extern struct security_hook_heads security_hook_heads; -extern char *lsm_names; +#define LSM_HOOK_INIT(NAME, HOOK) \ + { \ + .scalls = static_calls_table.NAME, \ + .hook = { .NAME = HOOK } \ + } extern void security_add_hooks(struct security_hook_list *hooks, int count, const struct lsm_id *lsmid); @@ -137,9 +157,6 @@ struct lsm_info { struct lsm_blob_sizes *blobs; /* Optional: for blob sharing. */ }; -extern struct lsm_info __start_lsm_info[], __end_lsm_info[]; -extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[]; - #define DEFINE_LSM(lsm) \ static struct lsm_info __lsm_##lsm \ __used __section(".lsm_info.init") \ @@ -150,6 +167,28 @@ extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[]; __used __section(".early_lsm_info.init") \ __aligned(sizeof(unsigned long)) -extern int lsm_inode_alloc(struct inode *inode); +/* DO NOT tamper with these variables outside of the LSM framework */ +extern char *lsm_names; +extern struct lsm_static_calls_table static_calls_table __ro_after_init; +extern struct lsm_info __start_lsm_info[], __end_lsm_info[]; +extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[]; + +/** + * lsm_get_xattr_slot - Return the next available slot and increment the index + * @xattrs: array storing LSM-provided xattrs + * @xattr_count: number of already stored xattrs (updated) + * + * Retrieve the first available slot in the @xattrs array to fill with an xattr, + * and increment @xattr_count. + * + * Return: The slot to fill in @xattrs if non-NULL, NULL otherwise. + */ +static inline struct xattr *lsm_get_xattr_slot(struct xattr *xattrs, + int *xattr_count) +{ + if (unlikely(!xattrs)) + return NULL; + return &xattrs[(*xattr_count)++]; +} #endif /* ! __LINUX_LSM_HOOKS_H */ diff --git a/include/linux/security.h b/include/linux/security.h index 1390f1efb4f0..c37c32ebbdcd 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -83,6 +83,18 @@ enum lsm_event { LSM_POLICY_CHANGE, }; +struct dm_verity_digest { + const char *alg; + const u8 *digest; + size_t digest_len; +}; + +enum lsm_integrity_type { + LSM_INT_DMVERITY_SIG_VALID, + LSM_INT_DMVERITY_ROOTHASH, + LSM_INT_FSVERITY_BUILTINSIG_VALID, +}; + /* * These are reasons that can be passed to the security_locked_down() * LSM hook. Lockdown reasons that protect kernel integrity (ie, the @@ -399,6 +411,9 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer void security_inode_getsecid(struct inode *inode, u32 *secid); int security_inode_copy_up(struct dentry *src, struct cred **new); int security_inode_copy_up_xattr(struct dentry *src, const char *name); +int security_inode_setintegrity(const struct inode *inode, + enum lsm_integrity_type type, const void *value, + size_t size); int security_kernfs_init_security(struct kernfs_node *kn_dir, struct kernfs_node *kn); int security_file_permission(struct file *file, int mask); @@ -509,6 +524,11 @@ int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen); int security_locked_down(enum lockdown_reason what); int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, u32 *uctx_len, void *val, size_t val_len, u64 id, u64 flags); +int security_bdev_alloc(struct block_device *bdev); +void security_bdev_free(struct block_device *bdev); +int security_bdev_setintegrity(struct block_device *bdev, + enum lsm_integrity_type type, const void *value, + size_t size); #else /* CONFIG_SECURITY */ static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data) @@ -634,7 +654,7 @@ static inline int security_settime64(const struct timespec64 *ts, static inline int security_vm_enough_memory_mm(struct mm_struct *mm, long pages) { - return __vm_enough_memory(mm, pages, cap_vm_enough_memory(mm, pages)); + return __vm_enough_memory(mm, pages, !cap_vm_enough_memory(mm, pages)); } static inline int security_bprm_creds_for_exec(struct linux_binprm *bprm) @@ -1010,6 +1030,13 @@ static inline int security_inode_copy_up(struct dentry *src, struct cred **new) return 0; } +static inline int security_inode_setintegrity(const struct inode *inode, + enum lsm_integrity_type type, + const void *value, size_t size) +{ + return 0; +} + static inline int security_kernfs_init_security(struct kernfs_node *kn_dir, struct kernfs_node *kn) { @@ -1483,6 +1510,23 @@ static inline int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, { return -EOPNOTSUPP; } + +static inline int security_bdev_alloc(struct block_device *bdev) +{ + return 0; +} + +static inline void security_bdev_free(struct block_device *bdev) +{ +} + +static inline int security_bdev_setintegrity(struct block_device *bdev, + enum lsm_integrity_type type, + const void *value, size_t size) +{ + return 0; +} + #endif /* CONFIG_SECURITY */ #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE) @@ -2090,6 +2134,7 @@ struct dentry *securityfs_create_symlink(const char *name, const char *target, const struct inode_operations *iops); extern void securityfs_remove(struct dentry *dentry); +extern void securityfs_recursive_remove(struct dentry *dentry); #else /* CONFIG_SECURITYFS */ @@ -2256,4 +2301,12 @@ static inline int security_uring_cmd(struct io_uring_cmd *ioucmd) #endif /* CONFIG_SECURITY */ #endif /* CONFIG_IO_URING */ +#ifdef CONFIG_SECURITY +extern void security_initramfs_populated(void); +#else +static inline void security_initramfs_populated(void) +{ +} +#endif /* CONFIG_SECURITY */ + #endif /* ! __LINUX_SECURITY_H */ diff --git a/include/linux/unroll.h b/include/linux/unroll.h new file mode 100644 index 000000000000..d42fd6366373 --- /dev/null +++ b/include/linux/unroll.h @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright (C) 2023 Google LLC. + */ + +#ifndef __UNROLL_H +#define __UNROLL_H + +#include <linux/args.h> + +#define UNROLL(N, MACRO, args...) CONCATENATE(__UNROLL_, N)(MACRO, args) + +#define __UNROLL_0(MACRO, args...) +#define __UNROLL_1(MACRO, args...) __UNROLL_0(MACRO, args) MACRO(0, args) +#define __UNROLL_2(MACRO, args...) __UNROLL_1(MACRO, args) MACRO(1, args) +#define __UNROLL_3(MACRO, args...) __UNROLL_2(MACRO, args) MACRO(2, args) +#define __UNROLL_4(MACRO, args...) __UNROLL_3(MACRO, args) MACRO(3, args) +#define __UNROLL_5(MACRO, args...) __UNROLL_4(MACRO, args) MACRO(4, args) +#define __UNROLL_6(MACRO, args...) __UNROLL_5(MACRO, args) MACRO(5, args) +#define __UNROLL_7(MACRO, args...) __UNROLL_6(MACRO, args) MACRO(6, args) +#define __UNROLL_8(MACRO, args...) __UNROLL_7(MACRO, args) MACRO(7, args) +#define __UNROLL_9(MACRO, args...) __UNROLL_8(MACRO, args) MACRO(8, args) +#define __UNROLL_10(MACRO, args...) __UNROLL_9(MACRO, args) MACRO(9, args) +#define __UNROLL_11(MACRO, args...) __UNROLL_10(MACRO, args) MACRO(10, args) +#define __UNROLL_12(MACRO, args...) __UNROLL_11(MACRO, args) MACRO(11, args) +#define __UNROLL_13(MACRO, args...) __UNROLL_12(MACRO, args) MACRO(12, args) +#define __UNROLL_14(MACRO, args...) __UNROLL_13(MACRO, args) MACRO(13, args) +#define __UNROLL_15(MACRO, args...) __UNROLL_14(MACRO, args) MACRO(14, args) +#define __UNROLL_16(MACRO, args...) __UNROLL_15(MACRO, args) MACRO(15, args) +#define __UNROLL_17(MACRO, args...) __UNROLL_16(MACRO, args) MACRO(16, args) +#define __UNROLL_18(MACRO, args...) __UNROLL_17(MACRO, args) MACRO(17, args) +#define __UNROLL_19(MACRO, args...) __UNROLL_18(MACRO, args) MACRO(18, args) +#define __UNROLL_20(MACRO, args...) __UNROLL_19(MACRO, args) MACRO(19, args) + +#endif /* __UNROLL_H */ diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index d676ed2b246e..75e21a135483 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -143,6 +143,9 @@ #define AUDIT_MAC_UNLBL_STCDEL 1417 /* NetLabel: del a static label */ #define AUDIT_MAC_CALIPSO_ADD 1418 /* NetLabel: add CALIPSO DOI entry */ #define AUDIT_MAC_CALIPSO_DEL 1419 /* NetLabel: del CALIPSO DOI entry */ +#define AUDIT_IPE_ACCESS 1420 /* IPE denial or grant */ +#define AUDIT_IPE_CONFIG_CHANGE 1421 /* IPE config change */ +#define AUDIT_IPE_POLICY_LOAD 1422 /* IPE policy load */ #define AUDIT_FIRST_KERN_ANOM_MSG 1700 #define AUDIT_LAST_KERN_ANOM_MSG 1799 diff --git a/include/uapi/linux/lsm.h b/include/uapi/linux/lsm.h index 33d8c9f4aa6b..938593dfd5da 100644 --- a/include/uapi/linux/lsm.h +++ b/include/uapi/linux/lsm.h @@ -64,6 +64,7 @@ struct lsm_ctx { #define LSM_ID_LANDLOCK 110 #define LSM_ID_IMA 111 #define LSM_ID_EVM 112 +#define LSM_ID_IPE 113 /* * LSM_ATTR_XXX definitions identify different LSM attributes diff --git a/init/initramfs.c b/init/initramfs.c index 814241b64827..bc911e466d5b 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -17,6 +17,7 @@ #include <linux/namei.h> #include <linux/init_syscalls.h> #include <linux/umh.h> +#include <linux/security.h> #include "do_mounts.h" @@ -712,6 +713,8 @@ static void __init do_populate_rootfs(void *unused, async_cookie_t cookie) } done: + security_initramfs_populated(); + /* * If the initrd region is overlapped with crashkernel reserved region, * free only memory that is not part of crashkernel region. diff --git a/init/main.c b/init/main.c index 206acdde51f5..c4778edae797 100644 --- a/init/main.c +++ b/init/main.c @@ -922,8 +922,11 @@ void start_kernel(void) boot_cpu_init(); page_address_init(); pr_notice("%s", linux_banner); - early_security_init(); setup_arch(&command_line); + /* Static keys and static calls are needed by LSMs */ + jump_label_init(); + static_call_init(); + early_security_init(); setup_boot_config(); setup_command_line(command_line); setup_nr_cpu_ids(); @@ -934,7 +937,6 @@ void start_kernel(void) pr_notice("Kernel command line: %s\n", saved_command_line); /* parameters may set static keys */ - jump_label_init(); parse_early_param(); after_dashes = parse_args("Booting kernel", static_command_line, __start___param, diff --git a/scripts/Makefile b/scripts/Makefile index dccef663ca82..6bcda4b9d054 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -55,6 +55,7 @@ targets += module.lds subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins subdir-$(CONFIG_MODVERSIONS) += genksyms subdir-$(CONFIG_SECURITY_SELINUX) += selinux +subdir-$(CONFIG_SECURITY_IPE) += ipe # Let clean descend into subdirs subdir- += basic dtc gdb kconfig mod diff --git a/scripts/ipe/Makefile b/scripts/ipe/Makefile new file mode 100644 index 000000000000..e87553fbb8d6 --- /dev/null +++ b/scripts/ipe/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +subdir-y := polgen diff --git a/scripts/ipe/polgen/.gitignore b/scripts/ipe/polgen/.gitignore new file mode 100644 index 000000000000..b6f05cf3dc0e --- /dev/null +++ b/scripts/ipe/polgen/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +polgen diff --git a/scripts/ipe/polgen/Makefile b/scripts/ipe/polgen/Makefile new file mode 100644 index 000000000000..c20456a2f2e9 --- /dev/null +++ b/scripts/ipe/polgen/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +hostprogs-always-y := polgen +HOST_EXTRACFLAGS += \ + -I$(srctree)/include \ + -I$(srctree)/include/uapi \ diff --git a/scripts/ipe/polgen/polgen.c b/scripts/ipe/polgen/polgen.c new file mode 100644 index 000000000000..c6283b3ff006 --- /dev/null +++ b/scripts/ipe/polgen/polgen.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include <stdlib.h> +#include <stddef.h> +#include <stdio.h> +#include <unistd.h> +#include <errno.h> + +static void usage(const char *const name) +{ + printf("Usage: %s OutputFile (PolicyFile)\n", name); + exit(EINVAL); +} + +static int policy_to_buffer(const char *pathname, char **buffer, size_t *size) +{ + size_t fsize; + size_t read; + char *lbuf; + int rc = 0; + FILE *fd; + + fd = fopen(pathname, "r"); + if (!fd) { + rc = errno; + goto out; + } + + fseek(fd, 0, SEEK_END); + fsize = ftell(fd); + rewind(fd); + + lbuf = malloc(fsize); + if (!lbuf) { + rc = ENOMEM; + goto out_close; + } + + read = fread((void *)lbuf, sizeof(*lbuf), fsize, fd); + if (read != fsize) { + rc = -1; + goto out_free; + } + + *buffer = lbuf; + *size = fsize; + fclose(fd); + + return rc; + +out_free: + free(lbuf); +out_close: + fclose(fd); +out: + return rc; +} + +static int write_boot_policy(const char *pathname, const char *buf, size_t size) +{ + int rc = 0; + FILE *fd; + size_t i; + + fd = fopen(pathname, "w"); + if (!fd) { + rc = errno; + goto err; + } + + fprintf(fd, "/* This file is automatically generated."); + fprintf(fd, " Do not edit. */\n"); + fprintf(fd, "#include <linux/stddef.h>\n"); + fprintf(fd, "\nextern const char *const ipe_boot_policy;\n\n"); + fprintf(fd, "const char *const ipe_boot_policy =\n"); + + if (!buf || size == 0) { + fprintf(fd, "\tNULL;\n"); + fclose(fd); + return 0; + } + + fprintf(fd, "\t\""); + + for (i = 0; i < size; ++i) { + switch (buf[i]) { + case '"': + fprintf(fd, "\\\""); + break; + case '\'': + fprintf(fd, "'"); + break; + case '\n': + fprintf(fd, "\\n\"\n\t\""); + break; + case '\\': + fprintf(fd, "\\\\"); + break; + case '\t': + fprintf(fd, "\\t"); + break; + case '\?': + fprintf(fd, "\\?"); + break; + default: + fprintf(fd, "%c", buf[i]); + } + } + fprintf(fd, "\";\n"); + fclose(fd); + + return 0; + +err: + if (fd) + fclose(fd); + return rc; +} + +int main(int argc, const char *const argv[]) +{ + char *policy = NULL; + size_t len = 0; + int rc = 0; + + if (argc < 2) + usage(argv[0]); + + if (argc > 2) { + rc = policy_to_buffer(argv[2], &policy, &len); + if (rc != 0) + goto cleanup; + } + + rc = write_boot_policy(argv[1], policy, len); +cleanup: + if (policy) + free(policy); + if (rc != 0) + perror("An error occurred during policy conversion: "); + return rc; +} diff --git a/security/Kconfig b/security/Kconfig index a93c1a9b7c28..28e685f53bd1 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -224,6 +224,7 @@ source "security/yama/Kconfig" source "security/safesetid/Kconfig" source "security/lockdown/Kconfig" source "security/landlock/Kconfig" +source "security/ipe/Kconfig" source "security/integrity/Kconfig" @@ -263,11 +264,11 @@ endchoice config LSM string "Ordered list of enabled LSMs" - default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK - default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR - default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO - default "landlock,lockdown,yama,loadpin,safesetid,bpf" if DEFAULT_SECURITY_DAC - default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,bpf" + default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,ipe,bpf" if DEFAULT_SECURITY_SMACK + default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,ipe,bpf" if DEFAULT_SECURITY_APPARMOR + default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,ipe,bpf" if DEFAULT_SECURITY_TOMOYO + default "landlock,lockdown,yama,loadpin,safesetid,ipe,bpf" if DEFAULT_SECURITY_DAC + default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,ipe,bpf" help A comma-separated list of LSMs, in initialization order. Any LSMs left off this list, except for those with order diff --git a/security/Makefile b/security/Makefile index 59f238490665..cc0982214b84 100644 --- a/security/Makefile +++ b/security/Makefile @@ -25,6 +25,7 @@ obj-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown/ obj-$(CONFIG_CGROUPS) += device_cgroup.o obj-$(CONFIG_BPF_LSM) += bpf/ obj-$(CONFIG_SECURITY_LANDLOCK) += landlock/ +obj-$(CONFIG_SECURITY_IPE) += ipe/ # Object integrity file lists obj-$(CONFIG_INTEGRITY) += integrity/ diff --git a/security/apparmor/include/net.h b/security/apparmor/include/net.h index 67bf888c3bd6..c42ed8a73f1c 100644 --- a/security/apparmor/include/net.h +++ b/security/apparmor/include/net.h @@ -51,10 +51,9 @@ struct aa_sk_ctx { struct aa_label *peer; }; -#define SK_CTX(X) ((X)->sk_security) static inline struct aa_sk_ctx *aa_sock(const struct sock *sk) { - return sk->sk_security; + return sk->sk_security + apparmor_blob_sizes.lbs_sock; } #define DEFINE_AUDIT_NET(NAME, OP, SK, F, T, P) \ diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 808060f9effb..f5d05297d59e 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -1058,27 +1058,12 @@ static int apparmor_userns_create(const struct cred *cred) return error; } -static int apparmor_sk_alloc_security(struct sock *sk, int family, gfp_t flags) -{ - struct aa_sk_ctx *ctx; - - ctx = kzalloc(sizeof(*ctx), flags); - if (!ctx) - return -ENOMEM; - - sk->sk_security = ctx; - - return 0; -} - static void apparmor_sk_free_security(struct sock *sk) { struct aa_sk_ctx *ctx = aa_sock(sk); - sk->sk_security = NULL; aa_put_label(ctx->label); aa_put_label(ctx->peer); - kfree(ctx); } /** @@ -1433,6 +1418,7 @@ struct lsm_blob_sizes apparmor_blob_sizes __ro_after_init = { .lbs_cred = sizeof(struct aa_label *), .lbs_file = sizeof(struct aa_file_ctx), .lbs_task = sizeof(struct aa_task_ctx), + .lbs_sock = sizeof(struct aa_sk_ctx), }; static const struct lsm_id apparmor_lsmid = { @@ -1478,7 +1464,6 @@ static struct security_hook_list apparmor_hooks[] __ro_after_init = { LSM_HOOK_INIT(getprocattr, apparmor_getprocattr), LSM_HOOK_INIT(setprocattr, apparmor_setprocattr), - LSM_HOOK_INIT(sk_alloc_security, apparmor_sk_alloc_security), LSM_HOOK_INIT(sk_free_security, apparmor_sk_free_security), LSM_HOOK_INIT(sk_clone_security, apparmor_sk_clone_security), diff --git a/security/apparmor/net.c b/security/apparmor/net.c index 87e934b2b548..77413a519117 100644 --- a/security/apparmor/net.c +++ b/security/apparmor/net.c @@ -151,7 +151,7 @@ static int aa_label_sk_perm(const struct cred *subj_cred, const char *op, u32 request, struct sock *sk) { - struct aa_sk_ctx *ctx = SK_CTX(sk); + struct aa_sk_ctx *ctx = aa_sock(sk); int error = 0; AA_BUG(!label); diff --git a/security/commoncap.c b/security/commoncap.c index 162d96b3a676..cefad323a0b1 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -1396,17 +1396,12 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, * Determine whether the allocation of a new virtual mapping by the current * task is permitted. * - * Return: 1 if permission is granted, 0 if not. + * Return: 0 if permission granted, negative error code if not. */ int cap_vm_enough_memory(struct mm_struct *mm, long pages) { - int cap_sys_admin = 0; - - if (cap_capable(current_cred(), &init_user_ns, - CAP_SYS_ADMIN, CAP_OPT_NOAUDIT) == 0) - cap_sys_admin = 1; - - return cap_sys_admin; + return cap_capable(current_cred(), &init_user_ns, CAP_SYS_ADMIN, + CAP_OPT_NOAUDIT); } /** diff --git a/security/inode.c b/security/inode.c index 9e7cde913667..da3ab44c8e57 100644 --- a/security/inode.c +++ b/security/inode.c @@ -296,7 +296,7 @@ void securityfs_remove(struct dentry *dentry) { struct inode *dir; - if (!dentry || IS_ERR(dentry)) + if (IS_ERR_OR_NULL(dentry)) return; dir = d_inode(dentry->d_parent); @@ -313,6 +313,31 @@ void securityfs_remove(struct dentry *dentry) } EXPORT_SYMBOL_GPL(securityfs_remove); +static void remove_one(struct dentry *victim) +{ + simple_release_fs(&mount, &mount_count); +} + +/** + * securityfs_recursive_remove - recursively removes a file or directory + * + * @dentry: a pointer to a the dentry of the file or directory to be removed. + * + * This function recursively removes a file or directory in securityfs that was + * previously created with a call to another securityfs function (like + * securityfs_create_file() or variants thereof.) + */ +void securityfs_recursive_remove(struct dentry *dentry) +{ + if (IS_ERR_OR_NULL(dentry)) + return; + + simple_pin_fs(&fs_type, &mount, &mount_count); + simple_recursive_removal(dentry, remove_one); + simple_release_fs(&mount, &mount_count); +} +EXPORT_SYMBOL_GPL(securityfs_recursive_remove); + #ifdef CONFIG_SECURITY static struct dentry *lsm_dentry; static ssize_t lsm_read(struct file *filp, char __user *buf, size_t count, diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 62fe66dd53ce..6924ed508ebd 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -1000,7 +1000,7 @@ static int evm_inode_copy_up_xattr(struct dentry *src, const char *name) case EVM_XATTR_HMAC: case EVM_IMA_XATTR_DIGSIG: default: - rc = 1; /* discard */ + rc = -ECANCELED; /* discard */ } kfree(xattr_data); diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index c51e24d24d1e..3c323ca213d4 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -223,7 +223,7 @@ static inline void ima_inode_set_iint(const struct inode *inode, struct ima_iint_cache *ima_iint_find(struct inode *inode); struct ima_iint_cache *ima_inode_get(struct inode *inode); -void ima_inode_free(struct inode *inode); +void ima_inode_free_rcu(void *inode_security); void __init ima_iintcache_init(void); extern const int read_idmap[]; diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c index e23412a2c56b..00b249101f98 100644 --- a/security/integrity/ima/ima_iint.c +++ b/security/integrity/ima/ima_iint.c @@ -109,22 +109,18 @@ struct ima_iint_cache *ima_inode_get(struct inode *inode) } /** - * ima_inode_free - Called on inode free - * @inode: Pointer to the inode + * ima_inode_free_rcu - Called to free an inode via a RCU callback + * @inode_security: The inode->i_security pointer * - * Free the iint associated with an inode. + * Free the IMA data associated with an inode. */ -void ima_inode_free(struct inode *inode) +void ima_inode_free_rcu(void *inode_security) { - struct ima_iint_cache *iint; - - if (!IS_IMA(inode)) - return; - - iint = ima_iint_find(inode); - ima_inode_set_iint(inode, NULL); + struct ima_iint_cache **iint_p = inode_security + ima_blob_sizes.lbs_inode; - ima_iint_free(iint); + /* *iint_p should be NULL if !IS_IMA(inode) */ + if (*iint_p) + ima_iint_free(*iint_p); } static void ima_iint_init_once(void *foo) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index f04f43af651c..5b3394864b21 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -1193,7 +1193,7 @@ static struct security_hook_list ima_hooks[] __ro_after_init = { #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS LSM_HOOK_INIT(kernel_module_request, ima_kernel_module_request), #endif - LSM_HOOK_INIT(inode_free_security, ima_inode_free), + LSM_HOOK_INIT(inode_free_security_rcu, ima_inode_free_rcu), }; static const struct lsm_id ima_lsmid = { diff --git a/security/ipe/.gitignore b/security/ipe/.gitignore new file mode 100644 index 000000000000..6e9939be1cb7 --- /dev/null +++ b/security/ipe/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +boot_policy.c diff --git a/security/ipe/Kconfig b/security/ipe/Kconfig new file mode 100644 index 000000000000..3ab582606ed2 --- /dev/null +++ b/security/ipe/Kconfig @@ -0,0 +1,97 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Integrity Policy Enforcement (IPE) configuration +# + +menuconfig SECURITY_IPE + bool "Integrity Policy Enforcement (IPE)" + depends on SECURITY && SECURITYFS && AUDIT && AUDITSYSCALL + select PKCS7_MESSAGE_PARSER + select SYSTEM_DATA_VERIFICATION + select IPE_PROP_DM_VERITY if DM_VERITY + select IPE_PROP_DM_VERITY_SIGNATURE if DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG + select IPE_PROP_FS_VERITY if FS_VERITY + select IPE_PROP_FS_VERITY_BUILTIN_SIG if FS_VERITY && FS_VERITY_BUILTIN_SIGNATURES + help + This option enables the Integrity Policy Enforcement LSM + allowing users to define a policy to enforce a trust-based access + control. A key feature of IPE is a customizable policy to allow + admins to reconfigure trust requirements on the fly. + + If unsure, answer N. + +if SECURITY_IPE +config IPE_BOOT_POLICY + string "Integrity policy to apply on system startup" + help + This option specifies a filepath to an IPE policy that is compiled + into the kernel. This policy will be enforced until a policy update + is deployed via the $securityfs/ipe/policies/$policy_name/active + interface. + + If unsure, leave blank. + +menu "IPE Trust Providers" + +config IPE_PROP_DM_VERITY + bool "Enable support for dm-verity based on root hash" + depends on DM_VERITY + help + This option enables the 'dmverity_roothash' property within IPE + policies. The property evaluates to TRUE when a file from a dm-verity + volume is evaluated, and the volume's root hash matches the value + supplied in the policy. + +config IPE_PROP_DM_VERITY_SIGNATURE + bool "Enable support for dm-verity based on root hash signature" + depends on DM_VERITY && DM_VERITY_VERIFY_ROOTHASH_SIG + help + This option enables the 'dmverity_signature' property within IPE + policies. The property evaluates to TRUE when a file from a dm-verity + volume, which has been mounted with a valid signed root hash, + is evaluated. + + If unsure, answer Y. + +config IPE_PROP_FS_VERITY + bool "Enable support for fs-verity based on file digest" + depends on FS_VERITY + help + This option enables the 'fsverity_digest' property within IPE + policies. The property evaluates to TRUE when a file is fsverity + enabled and its digest matches the supplied digest value in the + policy. + + if unsure, answer Y. + +config IPE_PROP_FS_VERITY_BUILTIN_SIG + bool "Enable support for fs-verity based on builtin signature" + depends on FS_VERITY && FS_VERITY_BUILTIN_SIGNATURES + help + This option enables the 'fsverity_signature' property within IPE + policies. The property evaluates to TRUE when a file is fsverity + enabled and it has a valid builtin signature whose signing cert + is in the .fs-verity keyring. + + if unsure, answer Y. + +endmenu + +config SECURITY_IPE_KUNIT_TEST + bool "Build KUnit tests for IPE" if !KUNIT_ALL_TESTS + depends on KUNIT=y + default KUNIT_ALL_TESTS + help + This builds the IPE KUnit tests. + + KUnit tests run during boot and output the results to the debug log + in TAP format (https://testanything.org/). Only useful for kernel devs + running KUnit test harness and are not for inclusion into a + production build. + + For more information on KUnit and unit tests in general please refer + to the KUnit documentation in Documentation/dev-tools/kunit/. + + If unsure, say N. + +endif diff --git a/security/ipe/Makefile b/security/ipe/Makefile new file mode 100644 index 000000000000..2ffabfa63fe9 --- /dev/null +++ b/security/ipe/Makefile @@ -0,0 +1,31 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. +# +# Makefile for building the IPE module as part of the kernel tree. +# + +quiet_cmd_polgen = IPE_POL $(2) + cmd_polgen = scripts/ipe/polgen/polgen security/ipe/boot_policy.c $(2) + +targets += boot_policy.c + +$(obj)/boot_policy.c: scripts/ipe/polgen/polgen $(CONFIG_IPE_BOOT_POLICY) FORCE + $(call if_changed,polgen,$(CONFIG_IPE_BOOT_POLICY)) + +obj-$(CONFIG_SECURITY_IPE) += \ + boot_policy.o \ + digest.o \ + eval.o \ + hooks.o \ + fs.o \ + ipe.o \ + policy.o \ + policy_fs.o \ + policy_parser.o \ + audit.o \ + +clean-files := boot_policy.c \ + +obj-$(CONFIG_SECURITY_IPE_KUNIT_TEST) += \ + policy_tests.o \ diff --git a/security/ipe/audit.c b/security/ipe/audit.c new file mode 100644 index 000000000000..f05f0caa4850 --- /dev/null +++ b/security/ipe/audit.c @@ -0,0 +1,292 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include <linux/slab.h> +#include <linux/audit.h> +#include <linux/types.h> +#include <crypto/hash.h> + +#include "ipe.h" +#include "eval.h" +#include "hooks.h" +#include "policy.h" +#include "audit.h" +#include "digest.h" + +#define ACTSTR(x) ((x) == IPE_ACTION_ALLOW ? "ALLOW" : "DENY") + +#define IPE_AUDIT_HASH_ALG "sha256" + +#define AUDIT_POLICY_LOAD_FMT "policy_name=\"%s\" policy_version=%hu.%hu.%hu "\ + "policy_digest=" IPE_AUDIT_HASH_ALG ":" +#define AUDIT_OLD_ACTIVE_POLICY_FMT "old_active_pol_name=\"%s\" "\ + "old_active_pol_version=%hu.%hu.%hu "\ + "old_policy_digest=" IPE_AUDIT_HASH_ALG ":" +#define AUDIT_OLD_ACTIVE_POLICY_NULL_FMT "old_active_pol_name=? "\ + "old_active_pol_version=? "\ + "old_policy_digest=?" +#define AUDIT_NEW_ACTIVE_POLICY_FMT "new_active_pol_name=\"%s\" "\ + "new_active_pol_version=%hu.%hu.%hu "\ + "new_policy_digest=" IPE_AUDIT_HASH_ALG ":" + +static const char *const audit_op_names[__IPE_OP_MAX + 1] = { + "EXECUTE", + "FIRMWARE", + "KMODULE", + "KEXEC_IMAGE", + "KEXEC_INITRAMFS", + "POLICY", + "X509_CERT", + "UNKNOWN", +}; + +static const char *const audit_hook_names[__IPE_HOOK_MAX] = { + "BPRM_CHECK", + "MMAP", + "MPROTECT", + "KERNEL_READ", + "KERNEL_LOAD", +}; + +static const char *const audit_prop_names[__IPE_PROP_MAX] = { + "boot_verified=FALSE", + "boot_verified=TRUE", + "dmverity_roothash=", + "dmverity_signature=FALSE", + "dmverity_signature=TRUE", + "fsverity_digest=", + "fsverity_signature=FALSE", + "fsverity_signature=TRUE", +}; + +/** + * audit_dmv_roothash() - audit the roothash of a dmverity_roothash property. + * @ab: Supplies a pointer to the audit_buffer to append to. + * @rh: Supplies a pointer to the digest structure. + */ +static void audit_dmv_roothash(struct audit_buffer *ab, const void *rh) +{ + audit_log_format(ab, "%s", audit_prop_names[IPE_PROP_DMV_ROOTHASH]); + ipe_digest_audit(ab, rh); +} + +/** + * audit_fsv_digest() - audit the digest of a fsverity_digest property. + * @ab: Supplies a pointer to the audit_buffer to append to. + * @d: Supplies a pointer to the digest structure. + */ +static void audit_fsv_digest(struct audit_buffer *ab, const void *d) +{ + audit_log_format(ab, "%s", audit_prop_names[IPE_PROP_FSV_DIGEST]); + ipe_digest_audit(ab, d); +} + +/** + * audit_rule() - audit an IPE policy rule. + * @ab: Supplies a pointer to the audit_buffer to append to. + * @r: Supplies a pointer to the ipe_rule to approximate a string form for. + */ +static void audit_rule(struct audit_buffer *ab, const struct ipe_rule *r) +{ + const struct ipe_prop *ptr; + + audit_log_format(ab, " rule=\"op=%s ", audit_op_names[r->op]); + + list_for_each_entry(ptr, &r->props, next) { + switch (ptr->type) { + case IPE_PROP_DMV_ROOTHASH: + audit_dmv_roothash(ab, ptr->value); + break; + case IPE_PROP_FSV_DIGEST: + audit_fsv_digest(ab, ptr->value); + break; + default: + audit_log_format(ab, "%s", audit_prop_names[ptr->type]); + break; + } + + audit_log_format(ab, " "); + } + + audit_log_format(ab, "action=%s\"", ACTSTR(r->action)); +} + +/** + * ipe_audit_match() - Audit a rule match in a policy evaluation. + * @ctx: Supplies a pointer to the evaluation context that was used in the + * evaluation. + * @match_type: Supplies the scope of the match: rule, operation default, + * global default. + * @act: Supplies the IPE's evaluation decision, deny or allow. + * @r: Supplies a pointer to the rule that was matched, if possible. + */ +void ipe_audit_match(const struct ipe_eval_ctx *const ctx, + enum ipe_match match_type, + enum ipe_action_type act, const struct ipe_rule *const r) +{ + const char *op = audit_op_names[ctx->op]; + char comm[sizeof(current->comm)]; + struct audit_buffer *ab; + struct inode *inode; + + if (act != IPE_ACTION_DENY && !READ_ONCE(success_audit)) + return; + + ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN, + AUDIT_IPE_ACCESS); + if (!ab) + return; + + audit_log_format(ab, "ipe_op=%s ipe_hook=%s enforcing=%d pid=%d comm=", + op, audit_hook_names[ctx->hook], READ_ONCE(enforce), + task_tgid_nr(current)); + audit_log_untrustedstring(ab, get_task_comm(comm, current)); + + if (ctx->file) { + audit_log_d_path(ab, " path=", &ctx->file->f_path); + inode = file_inode(ctx->file); + if (inode) { + audit_log_format(ab, " dev="); + audit_log_untrustedstring(ab, inode->i_sb->s_id); + audit_log_format(ab, " ino=%lu", inode->i_ino); + } else { + audit_log_format(ab, " dev=? ino=?"); + } + } else { + audit_log_format(ab, " path=? dev=? ino=?"); + } + + if (match_type == IPE_MATCH_RULE) + audit_rule(ab, r); + else if (match_type == IPE_MATCH_TABLE) + audit_log_format(ab, " rule=\"DEFAULT op=%s action=%s\"", op, + ACTSTR(act)); + else + audit_log_format(ab, " rule=\"DEFAULT action=%s\"", + ACTSTR(act)); + + audit_log_end(ab); +} + +/** + * audit_policy() - Audit a policy's name, version and thumbprint to @ab. + * @ab: Supplies a pointer to the audit buffer to append to. + * @audit_format: Supplies a pointer to the audit format string + * @p: Supplies a pointer to the policy to audit. + */ +static void audit_policy(struct audit_buffer *ab, + const char *audit_format, + const struct ipe_policy *const p) +{ + SHASH_DESC_ON_STACK(desc, tfm); + struct crypto_shash *tfm; + u8 *digest = NULL; + + tfm = crypto_alloc_shash(IPE_AUDIT_HASH_ALG, 0, 0); + if (IS_ERR(tfm)) + return; + + desc->tfm = tfm; + + digest = kzalloc(crypto_shash_digestsize(tfm), GFP_KERNEL); + if (!digest) + goto out; + + if (crypto_shash_init(desc)) + goto out; + + if (crypto_shash_update(desc, p->pkcs7, p->pkcs7len)) + goto out; + + if (crypto_shash_final(desc, digest)) + goto out; + + audit_log_format(ab, audit_format, p->parsed->name, + p->parsed->version.major, p->parsed->version.minor, + p->parsed->version.rev); + audit_log_n_hex(ab, digest, crypto_shash_digestsize(tfm)); + +out: + kfree(digest); + crypto_free_shash(tfm); +} + +/** + * ipe_audit_policy_activation() - Audit a policy being activated. + * @op: Supplies a pointer to the previously activated policy to audit. + * @np: Supplies a pointer to the newly activated policy to audit. + */ +void ipe_audit_policy_activation(const struct ipe_policy *const op, + const struct ipe_policy *const np) +{ + struct audit_buffer *ab; + + ab = audit_log_start(audit_context(), GFP_KERNEL, + AUDIT_IPE_CONFIG_CHANGE); + if (!ab) + return; + + if (op) { + audit_policy(ab, AUDIT_OLD_ACTIVE_POLICY_FMT, op); + audit_log_format(ab, " "); + } else { + /* + * old active policy can be NULL if there is no kernel + * built-in policy + */ + audit_log_format(ab, AUDIT_OLD_ACTIVE_POLICY_NULL_FMT); + audit_log_format(ab, " "); + } + audit_policy(ab, AUDIT_NEW_ACTIVE_POLICY_FMT, np); + audit_log_format(ab, " auid=%u ses=%u lsm=ipe res=1", + from_kuid(&init_user_ns, audit_get_loginuid(current)), + audit_get_sessionid(current)); + + audit_log_end(ab); +} + +/** + * ipe_audit_policy_load() - Audit a policy being loaded into the kernel. + * @p: Supplies a pointer to the policy to audit. + */ +void ipe_audit_policy_load(const struct ipe_policy *const p) +{ + struct audit_buffer *ab; + + ab = audit_log_start(audit_context(), GFP_KERNEL, + AUDIT_IPE_POLICY_LOAD); + if (!ab) + return; + + audit_policy(ab, AUDIT_POLICY_LOAD_FMT, p); + audit_log_format(ab, " auid=%u ses=%u lsm=ipe res=1", + from_kuid(&init_user_ns, audit_get_loginuid(current)), + audit_get_sessionid(current)); + + audit_log_end(ab); +} + +/** + * ipe_audit_enforce() - Audit a change in IPE's enforcement state. + * @new_enforce: The new value enforce to be set. + * @old_enforce: The old value currently in enforce. + */ +void ipe_audit_enforce(bool new_enforce, bool old_enforce) +{ + struct audit_buffer *ab; + + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_MAC_STATUS); + if (!ab) + return; + + audit_log(audit_context(), GFP_KERNEL, AUDIT_MAC_STATUS, + "enforcing=%d old_enforcing=%d auid=%u ses=%u" + " enabled=1 old-enabled=1 lsm=ipe res=1", + new_enforce, old_enforce, + from_kuid(&init_user_ns, audit_get_loginuid(current)), + audit_get_sessionid(current)); + + audit_log_end(ab); +} diff --git a/security/ipe/audit.h b/security/ipe/audit.h new file mode 100644 index 000000000000..ed2620846a79 --- /dev/null +++ b/security/ipe/audit.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_AUDIT_H +#define _IPE_AUDIT_H + +#include "policy.h" + +void ipe_audit_match(const struct ipe_eval_ctx *const ctx, + enum ipe_match match_type, + enum ipe_action_type act, const struct ipe_rule *const r); +void ipe_audit_policy_load(const struct ipe_policy *const p); +void ipe_audit_policy_activation(const struct ipe_policy *const op, + const struct ipe_policy *const np); +void ipe_audit_enforce(bool new_enforce, bool old_enforce); + +#endif /* _IPE_AUDIT_H */ diff --git a/security/ipe/digest.c b/security/ipe/digest.c new file mode 100644 index 000000000000..493716370570 --- /dev/null +++ b/security/ipe/digest.c @@ -0,0 +1,118 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include "digest.h" + +/** + * ipe_digest_parse() - parse a digest in IPE's policy. + * @valstr: Supplies the string parsed from the policy. + * + * Digests in IPE are defined in a standard way: + * <alg_name>:<hex> + * + * Use this function to create a property to parse the digest + * consistently. The parsed digest will be saved in @value in IPE's + * policy. + * + * Return: The parsed digest_info structure on success. If an error occurs, + * the function will return the error value (via ERR_PTR). + */ +struct digest_info *ipe_digest_parse(const char *valstr) +{ + struct digest_info *info = NULL; + char *sep, *raw_digest; + size_t raw_digest_len; + u8 *digest = NULL; + char *alg = NULL; + int rc = 0; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return ERR_PTR(-ENOMEM); + + sep = strchr(valstr, ':'); + if (!sep) { + rc = -EBADMSG; + goto err; + } + + alg = kstrndup(valstr, sep - valstr, GFP_KERNEL); + if (!alg) { + rc = -ENOMEM; + goto err; + } + + raw_digest = sep + 1; + raw_digest_len = strlen(raw_digest); + + info->digest_len = (raw_digest_len + 1) / 2; + digest = kzalloc(info->digest_len, GFP_KERNEL); + if (!digest) { + rc = -ENOMEM; + goto err; + } + + rc = hex2bin(digest, raw_digest, info->digest_len); + if (rc < 0) { + rc = -EINVAL; + goto err; + } + + info->alg = alg; + info->digest = digest; + return info; + +err: + kfree(alg); + kfree(digest); + kfree(info); + return ERR_PTR(rc); +} + +/** + * ipe_digest_eval() - evaluate an IPE digest against another digest. + * @expected: Supplies the policy-provided digest value. + * @digest: Supplies the digest to compare against the policy digest value. + * + * Return: + * * %true - digests match + * * %false - digests do not match + */ +bool ipe_digest_eval(const struct digest_info *expected, + const struct digest_info *digest) +{ + return (expected->digest_len == digest->digest_len) && + (!strcmp(expected->alg, digest->alg)) && + (!memcmp(expected->digest, digest->digest, expected->digest_len)); +} + +/** + * ipe_digest_free() - free an IPE digest. + * @info: Supplies a pointer the policy-provided digest to free. + */ +void ipe_digest_free(struct digest_info *info) +{ + if (IS_ERR_OR_NULL(info)) + return; + + kfree(info->alg); + kfree(info->digest); + kfree(info); +} + +/** + * ipe_digest_audit() - audit a digest that was sourced from IPE's policy. + * @ab: Supplies the audit_buffer to append the formatted result. + * @info: Supplies a pointer to source the audit record from. + * + * Digests in IPE are audited in this format: + * <alg_name>:<hex> + */ +void ipe_digest_audit(struct audit_buffer *ab, const struct digest_info *info) +{ + audit_log_untrustedstring(ab, info->alg); + audit_log_format(ab, ":"); + audit_log_n_hex(ab, info->digest, info->digest_len); +} diff --git a/security/ipe/digest.h b/security/ipe/digest.h new file mode 100644 index 000000000000..52c9b3844a38 --- /dev/null +++ b/security/ipe/digest.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_DIGEST_H +#define _IPE_DIGEST_H + +#include <linux/types.h> +#include <linux/audit.h> + +#include "policy.h" + +struct digest_info { + const char *alg; + const u8 *digest; + size_t digest_len; +}; + +struct digest_info *ipe_digest_parse(const char *valstr); +void ipe_digest_free(struct digest_info *digest_info); +void ipe_digest_audit(struct audit_buffer *ab, const struct digest_info *val); +bool ipe_digest_eval(const struct digest_info *expected, + const struct digest_info *digest); + +#endif /* _IPE_DIGEST_H */ diff --git a/security/ipe/eval.c b/security/ipe/eval.c new file mode 100644 index 000000000000..21439c5be336 --- /dev/null +++ b/security/ipe/eval.c @@ -0,0 +1,393 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include <linux/fs.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/file.h> +#include <linux/sched.h> +#include <linux/rcupdate.h> +#include <linux/moduleparam.h> +#include <linux/fsverity.h> + +#include "ipe.h" +#include "eval.h" +#include "policy.h" +#include "audit.h" +#include "digest.h" + +struct ipe_policy __rcu *ipe_active_policy; +bool success_audit; +bool enforce = true; +#define INO_BLOCK_DEV(ino) ((ino)->i_sb->s_bdev) + +#define FILE_SUPERBLOCK(f) ((f)->f_path.mnt->mnt_sb) + +/** + * build_ipe_sb_ctx() - Build initramfs field of an ipe evaluation context. + * @ctx: Supplies a pointer to the context to be populated. + * @file: Supplies the file struct of the file triggered IPE event. + */ +static void build_ipe_sb_ctx(struct ipe_eval_ctx *ctx, const struct file *const file) +{ + ctx->initramfs = ipe_sb(FILE_SUPERBLOCK(file))->initramfs; +} + +#ifdef CONFIG_IPE_PROP_DM_VERITY +/** + * build_ipe_bdev_ctx() - Build ipe_bdev field of an evaluation context. + * @ctx: Supplies a pointer to the context to be populated. + * @ino: Supplies the inode struct of the file triggered IPE event. + */ +static void build_ipe_bdev_ctx(struct ipe_eval_ctx *ctx, const struct inode *const ino) +{ + if (INO_BLOCK_DEV(ino)) + ctx->ipe_bdev = ipe_bdev(INO_BLOCK_DEV(ino)); +} +#else +static void build_ipe_bdev_ctx(struct ipe_eval_ctx *ctx, const struct inode *const ino) +{ +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + +#ifdef CONFIG_IPE_PROP_FS_VERITY +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +static void build_ipe_inode_blob_ctx(struct ipe_eval_ctx *ctx, + const struct inode *const ino) +{ + ctx->ipe_inode = ipe_inode(ctx->ino); +} +#else +static inline void build_ipe_inode_blob_ctx(struct ipe_eval_ctx *ctx, + const struct inode *const ino) +{ +} +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ + +/** + * build_ipe_inode_ctx() - Build inode fields of an evaluation context. + * @ctx: Supplies a pointer to the context to be populated. + * @ino: Supplies the inode struct of the file triggered IPE event. + */ +static void build_ipe_inode_ctx(struct ipe_eval_ctx *ctx, const struct inode *const ino) +{ + ctx->ino = ino; + build_ipe_inode_blob_ctx(ctx, ino); +} +#else +static void build_ipe_inode_ctx(struct ipe_eval_ctx *ctx, const struct inode *const ino) +{ +} +#endif /* CONFIG_IPE_PROP_FS_VERITY */ + +/** + * ipe_build_eval_ctx() - Build an ipe evaluation context. + * @ctx: Supplies a pointer to the context to be populated. + * @file: Supplies a pointer to the file to associated with the evaluation. + * @op: Supplies the IPE policy operation associated with the evaluation. + * @hook: Supplies the LSM hook associated with the evaluation. + */ +void ipe_build_eval_ctx(struct ipe_eval_ctx *ctx, + const struct file *file, + enum ipe_op_type op, + enum ipe_hook_type hook) +{ + struct inode *ino; + + ctx->file = file; + ctx->op = op; + ctx->hook = hook; + + if (file) { + build_ipe_sb_ctx(ctx, file); + ino = d_real_inode(file->f_path.dentry); + build_ipe_bdev_ctx(ctx, ino); + build_ipe_inode_ctx(ctx, ino); + } +} + +/** + * evaluate_boot_verified() - Evaluate @ctx for the boot verified property. + * @ctx: Supplies a pointer to the context being evaluated. + * + * Return: + * * %true - The current @ctx match the @p + * * %false - The current @ctx doesn't match the @p + */ +static bool evaluate_boot_verified(const struct ipe_eval_ctx *const ctx) +{ + return ctx->initramfs; +} + +#ifdef CONFIG_IPE_PROP_DM_VERITY +/** + * evaluate_dmv_roothash() - Evaluate @ctx against a dmv roothash property. + * @ctx: Supplies a pointer to the context being evaluated. + * @p: Supplies a pointer to the property being evaluated. + * + * Return: + * * %true - The current @ctx match the @p + * * %false - The current @ctx doesn't match the @p + */ +static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx, + struct ipe_prop *p) +{ + return !!ctx->ipe_bdev && + !!ctx->ipe_bdev->root_hash && + ipe_digest_eval(p->value, + ctx->ipe_bdev->root_hash); +} +#else +static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx, + struct ipe_prop *p) +{ + return false; +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + +#ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE +/** + * evaluate_dmv_sig_false() - Evaluate @ctx against a dmv sig false property. + * @ctx: Supplies a pointer to the context being evaluated. + * + * Return: + * * %true - The current @ctx match the property + * * %false - The current @ctx doesn't match the property + */ +static bool evaluate_dmv_sig_false(const struct ipe_eval_ctx *const ctx) +{ + return !ctx->ipe_bdev || (!ctx->ipe_bdev->dm_verity_signed); +} + +/** + * evaluate_dmv_sig_true() - Evaluate @ctx against a dmv sig true property. + * @ctx: Supplies a pointer to the context being evaluated. + * + * Return: + * * %true - The current @ctx match the property + * * %false - The current @ctx doesn't match the property + */ +static bool evaluate_dmv_sig_true(const struct ipe_eval_ctx *const ctx) +{ + return !evaluate_dmv_sig_false(ctx); +} +#else +static bool evaluate_dmv_sig_false(const struct ipe_eval_ctx *const ctx) +{ + return false; +} + +static bool evaluate_dmv_sig_true(const struct ipe_eval_ctx *const ctx) +{ + return false; +} +#endif /* CONFIG_IPE_PROP_DM_VERITY_SIGNATURE */ + +#ifdef CONFIG_IPE_PROP_FS_VERITY +/** + * evaluate_fsv_digest() - Evaluate @ctx against a fsv digest property. + * @ctx: Supplies a pointer to the context being evaluated. + * @p: Supplies a pointer to the property being evaluated. + * + * Return: + * * %true - The current @ctx match the @p + * * %false - The current @ctx doesn't match the @p + */ +static bool evaluate_fsv_digest(const struct ipe_eval_ctx *const ctx, + struct ipe_prop *p) +{ + enum hash_algo alg; + u8 digest[FS_VERITY_MAX_DIGEST_SIZE]; + struct digest_info info; + + if (!ctx->ino) + return false; + if (!fsverity_get_digest((struct inode *)ctx->ino, + digest, + NULL, + &alg)) + return false; + + info.alg = hash_algo_name[alg]; + info.digest = digest; + info.digest_len = hash_digest_size[alg]; + + return ipe_digest_eval(p->value, &info); +} +#else +static bool evaluate_fsv_digest(const struct ipe_eval_ctx *const ctx, + struct ipe_prop *p) +{ + return false; +} +#endif /* CONFIG_IPE_PROP_FS_VERITY */ + +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +/** + * evaluate_fsv_sig_false() - Evaluate @ctx against a fsv sig false property. + * @ctx: Supplies a pointer to the context being evaluated. + * + * Return: + * * %true - The current @ctx match the property + * * %false - The current @ctx doesn't match the property + */ +static bool evaluate_fsv_sig_false(const struct ipe_eval_ctx *const ctx) +{ + return !ctx->ino || + !IS_VERITY(ctx->ino) || + !ctx->ipe_inode || + !ctx->ipe_inode->fs_verity_signed; +} + +/** + * evaluate_fsv_sig_true() - Evaluate @ctx against a fsv sig true property. + * @ctx: Supplies a pointer to the context being evaluated. + * + * Return: + * * %true - The current @ctx match the property + * * %false - The current @ctx doesn't match the property + */ +static bool evaluate_fsv_sig_true(const struct ipe_eval_ctx *const ctx) +{ + return !evaluate_fsv_sig_false(ctx); +} +#else +static bool evaluate_fsv_sig_false(const struct ipe_eval_ctx *const ctx) +{ + return false; +} + +static bool evaluate_fsv_sig_true(const struct ipe_eval_ctx *const ctx) +{ + return false; +} +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ + +/** + * evaluate_property() - Analyze @ctx against a rule property. + * @ctx: Supplies a pointer to the context to be evaluated. + * @p: Supplies a pointer to the property to be evaluated. + * + * This function Determines whether the specified @ctx + * matches the conditions defined by a rule property @p. + * + * Return: + * * %true - The current @ctx match the @p + * * %false - The current @ctx doesn't match the @p + */ +static bool evaluate_property(const struct ipe_eval_ctx *const ctx, + struct ipe_prop *p) +{ + switch (p->type) { + case IPE_PROP_BOOT_VERIFIED_FALSE: + return !evaluate_boot_verified(ctx); + case IPE_PROP_BOOT_VERIFIED_TRUE: + return evaluate_boot_verified(ctx); + case IPE_PROP_DMV_ROOTHASH: + return evaluate_dmv_roothash(ctx, p); + case IPE_PROP_DMV_SIG_FALSE: + return evaluate_dmv_sig_false(ctx); + case IPE_PROP_DMV_SIG_TRUE: + return evaluate_dmv_sig_true(ctx); + case IPE_PROP_FSV_DIGEST: + return evaluate_fsv_digest(ctx, p); + case IPE_PROP_FSV_SIG_FALSE: + return evaluate_fsv_sig_false(ctx); + case IPE_PROP_FSV_SIG_TRUE: + return evaluate_fsv_sig_true(ctx); + default: + return false; + } +} + +/** + * ipe_evaluate_event() - Analyze @ctx against the current active policy. + * @ctx: Supplies a pointer to the context to be evaluated. + * + * This is the loop where all policy evaluations happen against the IPE policy. + * + * Return: + * * %0 - Success + * * %-EACCES - @ctx did not pass evaluation + */ +int ipe_evaluate_event(const struct ipe_eval_ctx *const ctx) +{ + const struct ipe_op_table *rules = NULL; + const struct ipe_rule *rule = NULL; + struct ipe_policy *pol = NULL; + struct ipe_prop *prop = NULL; + enum ipe_action_type action; + enum ipe_match match_type; + bool match = false; + int rc = 0; + + rcu_read_lock(); + + pol = rcu_dereference(ipe_active_policy); + if (!pol) { + rcu_read_unlock(); + return 0; + } + + if (ctx->op == IPE_OP_INVALID) { + if (pol->parsed->global_default_action == IPE_ACTION_INVALID) { + WARN(1, "no default rule set for unknown op, ALLOW it"); + action = IPE_ACTION_ALLOW; + } else { + action = pol->parsed->global_default_action; + } + match_type = IPE_MATCH_GLOBAL; + goto eval; + } + + rules = &pol->parsed->rules[ctx->op]; + + list_for_each_entry(rule, &rules->rules, next) { + match = true; + + list_for_each_entry(prop, &rule->props, next) { + match = evaluate_property(ctx, prop); + if (!match) + break; + } + + if (match) + break; + } + + if (match) { + action = rule->action; + match_type = IPE_MATCH_RULE; + } else if (rules->default_action != IPE_ACTION_INVALID) { + action = rules->default_action; + match_type = IPE_MATCH_TABLE; + } else { + action = pol->parsed->global_default_action; + match_type = IPE_MATCH_GLOBAL; + } + +eval: + ipe_audit_match(ctx, match_type, action, rule); + rcu_read_unlock(); + + if (action == IPE_ACTION_DENY) + rc = -EACCES; + + if (!READ_ONCE(enforce)) + rc = 0; + + return rc; +} + +/* Set the right module name */ +#ifdef KBUILD_MODNAME +#undef KBUILD_MODNAME +#define KBUILD_MODNAME "ipe" +#endif + +module_param(success_audit, bool, 0400); +MODULE_PARM_DESC(success_audit, "Start IPE with success auditing enabled"); +module_param(enforce, bool, 0400); +MODULE_PARM_DESC(enforce, "Start IPE in enforce or permissive mode"); diff --git a/security/ipe/eval.h b/security/ipe/eval.h new file mode 100644 index 000000000000..fef65a36468c --- /dev/null +++ b/security/ipe/eval.h @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_EVAL_H +#define _IPE_EVAL_H + +#include <linux/file.h> +#include <linux/types.h> + +#include "policy.h" +#include "hooks.h" + +#define IPE_EVAL_CTX_INIT ((struct ipe_eval_ctx){ 0 }) + +extern struct ipe_policy __rcu *ipe_active_policy; +extern bool success_audit; +extern bool enforce; + +struct ipe_superblock { + bool initramfs; +}; + +#ifdef CONFIG_IPE_PROP_DM_VERITY +struct ipe_bdev { +#ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE + bool dm_verity_signed; +#endif /* CONFIG_IPE_PROP_DM_VERITY_SIGNATURE */ + struct digest_info *root_hash; +}; +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +struct ipe_inode { + bool fs_verity_signed; +}; +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ + +struct ipe_eval_ctx { + enum ipe_op_type op; + enum ipe_hook_type hook; + + const struct file *file; + bool initramfs; +#ifdef CONFIG_IPE_PROP_DM_VERITY + const struct ipe_bdev *ipe_bdev; +#endif /* CONFIG_IPE_PROP_DM_VERITY */ +#ifdef CONFIG_IPE_PROP_FS_VERITY + const struct inode *ino; +#endif /* CONFIG_IPE_PROP_FS_VERITY */ +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG + const struct ipe_inode *ipe_inode; +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ +}; + +enum ipe_match { + IPE_MATCH_RULE = 0, + IPE_MATCH_TABLE, + IPE_MATCH_GLOBAL, + __IPE_MATCH_MAX +}; + +void ipe_build_eval_ctx(struct ipe_eval_ctx *ctx, + const struct file *file, + enum ipe_op_type op, + enum ipe_hook_type hook); +int ipe_evaluate_event(const struct ipe_eval_ctx *const ctx); + +#endif /* _IPE_EVAL_H */ diff --git a/security/ipe/fs.c b/security/ipe/fs.c new file mode 100644 index 000000000000..5b6d19fb844a --- /dev/null +++ b/security/ipe/fs.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include <linux/dcache.h> +#include <linux/security.h> + +#include "ipe.h" +#include "fs.h" +#include "eval.h" +#include "policy.h" +#include "audit.h" + +static struct dentry *np __ro_after_init; +static struct dentry *root __ro_after_init; +struct dentry *policy_root __ro_after_init; +static struct dentry *audit_node __ro_after_init; +static struct dentry *enforce_node __ro_after_init; + +/** + * setaudit() - Write handler for the securityfs node, "ipe/success_audit" + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * Return: + * * Length of buffer written - Success + * * %-EPERM - Insufficient permission + */ +static ssize_t setaudit(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + bool value; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + rc = kstrtobool_from_user(data, len, &value); + if (rc) + return rc; + + WRITE_ONCE(success_audit, value); + + return len; +} + +/** + * getaudit() - Read handler for the securityfs node, "ipe/success_audit" + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the read syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * Return: Length of buffer written + */ +static ssize_t getaudit(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + const char *result; + + result = ((READ_ONCE(success_audit)) ? "1" : "0"); + + return simple_read_from_buffer(data, len, offset, result, 1); +} + +/** + * setenforce() - Write handler for the securityfs node, "ipe/enforce" + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * Return: + * * Length of buffer written - Success + * * %-EPERM - Insufficient permission + */ +static ssize_t setenforce(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + bool new_value, old_value; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + old_value = READ_ONCE(enforce); + rc = kstrtobool_from_user(data, len, &new_value); + if (rc) + return rc; + + if (new_value != old_value) { + ipe_audit_enforce(new_value, old_value); + WRITE_ONCE(enforce, new_value); + } + + return len; +} + +/** + * getenforce() - Read handler for the securityfs node, "ipe/enforce" + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the read syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * Return: Length of buffer written + */ +static ssize_t getenforce(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + const char *result; + + result = ((READ_ONCE(enforce)) ? "1" : "0"); + + return simple_read_from_buffer(data, len, offset, result, 1); +} + +/** + * new_policy() - Write handler for the securityfs node, "ipe/new_policy". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * Return: + * * Length of buffer written - Success + * * %-EPERM - Insufficient permission + * * %-ENOMEM - Out of memory (OOM) + * * %-EBADMSG - Policy is invalid + * * %-ERANGE - Policy version number overflow + * * %-EINVAL - Policy version parsing error + * * %-EEXIST - Same name policy already deployed + */ +static ssize_t new_policy(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + struct ipe_policy *p = NULL; + char *copy = NULL; + int rc = 0; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + copy = memdup_user_nul(data, len); + if (IS_ERR(copy)) + return PTR_ERR(copy); + + p = ipe_new_policy(NULL, 0, copy, len); + if (IS_ERR(p)) { + rc = PTR_ERR(p); + goto out; + } + + rc = ipe_new_policyfs_node(p); + if (rc) + goto out; + + ipe_audit_policy_load(p); + +out: + if (rc < 0) + ipe_free_policy(p); + kfree(copy); + return (rc < 0) ? rc : len; +} + +static const struct file_operations np_fops = { + .write = new_policy, +}; + +static const struct file_operations audit_fops = { + .write = setaudit, + .read = getaudit, +}; + +static const struct file_operations enforce_fops = { + .write = setenforce, + .read = getenforce, +}; + +/** + * ipe_init_securityfs() - Initialize IPE's securityfs tree at fsinit. + * + * Return: %0 on success. If an error occurs, the function will return + * the -errno. + */ +static int __init ipe_init_securityfs(void) +{ + int rc = 0; + struct ipe_policy *ap; + + if (!ipe_enabled) + return -EOPNOTSUPP; + + root = securityfs_create_dir("ipe", NULL); + if (IS_ERR(root)) { + rc = PTR_ERR(root); + goto err; + } + + audit_node = securityfs_create_file("success_audit", 0600, root, + NULL, &audit_fops); + if (IS_ERR(audit_node)) { + rc = PTR_ERR(audit_node); + goto err; + } + + enforce_node = securityfs_create_file("enforce", 0600, root, NULL, + &enforce_fops); + if (IS_ERR(enforce_node)) { + rc = PTR_ERR(enforce_node); + goto err; + } + + policy_root = securityfs_create_dir("policies", root); + if (IS_ERR(policy_root)) { + rc = PTR_ERR(policy_root); + goto err; + } + + ap = rcu_access_pointer(ipe_active_policy); + if (ap) { + rc = ipe_new_policyfs_node(ap); + if (rc) + goto err; + } + + np = securityfs_create_file("new_policy", 0200, root, NULL, &np_fops); + if (IS_ERR(np)) { + rc = PTR_ERR(np); + goto err; + } + + return 0; +err: + securityfs_remove(np); + securityfs_remove(policy_root); + securityfs_remove(enforce_node); + securityfs_remove(audit_node); + securityfs_remove(root); + return rc; +} + +fs_initcall(ipe_init_securityfs); diff --git a/security/ipe/fs.h b/security/ipe/fs.h new file mode 100644 index 000000000000..0141ae8e86ec --- /dev/null +++ b/security/ipe/fs.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_FS_H +#define _IPE_FS_H + +#include "policy.h" + +extern struct dentry *policy_root __ro_after_init; + +int ipe_new_policyfs_node(struct ipe_policy *p); +void ipe_del_policyfs_node(struct ipe_policy *p); + +#endif /* _IPE_FS_H */ diff --git a/security/ipe/hooks.c b/security/ipe/hooks.c new file mode 100644 index 000000000000..d0323b81cd8f --- /dev/null +++ b/security/ipe/hooks.c @@ -0,0 +1,314 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include <linux/fs.h> +#include <linux/fs_struct.h> +#include <linux/types.h> +#include <linux/binfmts.h> +#include <linux/mman.h> +#include <linux/blk_types.h> + +#include "ipe.h" +#include "hooks.h" +#include "eval.h" +#include "digest.h" + +/** + * ipe_bprm_check_security() - ipe security hook function for bprm check. + * @bprm: Supplies a pointer to a linux_binprm structure to source the file + * being evaluated. + * + * This LSM hook is called when a binary is loaded through the exec + * family of system calls. + * + * Return: + * * %0 - Success + * * %-EACCES - Did not pass IPE policy + */ +int ipe_bprm_check_security(struct linux_binprm *bprm) +{ + struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT; + + ipe_build_eval_ctx(&ctx, bprm->file, IPE_OP_EXEC, IPE_HOOK_BPRM_CHECK); + return ipe_evaluate_event(&ctx); +} + +/** + * ipe_mmap_file() - ipe security hook function for mmap check. + * @f: File being mmap'd. Can be NULL in the case of anonymous memory. + * @reqprot: The requested protection on the mmap, passed from usermode. + * @prot: The effective protection on the mmap, resolved from reqprot and + * system configuration. + * @flags: Unused. + * + * This hook is called when a file is loaded through the mmap + * family of system calls. + * + * Return: + * * %0 - Success + * * %-EACCES - Did not pass IPE policy + */ +int ipe_mmap_file(struct file *f, unsigned long reqprot __always_unused, + unsigned long prot, unsigned long flags) +{ + struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT; + + if (prot & PROT_EXEC) { + ipe_build_eval_ctx(&ctx, f, IPE_OP_EXEC, IPE_HOOK_MMAP); + return ipe_evaluate_event(&ctx); + } + + return 0; +} + +/** + * ipe_file_mprotect() - ipe security hook function for mprotect check. + * @vma: Existing virtual memory area created by mmap or similar. + * @reqprot: The requested protection on the mmap, passed from usermode. + * @prot: The effective protection on the mmap, resolved from reqprot and + * system configuration. + * + * This LSM hook is called when a mmap'd region of memory is changing + * its protections via mprotect. + * + * Return: + * * %0 - Success + * * %-EACCES - Did not pass IPE policy + */ +int ipe_file_mprotect(struct vm_area_struct *vma, + unsigned long reqprot __always_unused, + unsigned long prot) +{ + struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT; + + /* Already Executable */ + if (vma->vm_flags & VM_EXEC) + return 0; + + if (prot & PROT_EXEC) { + ipe_build_eval_ctx(&ctx, vma->vm_file, IPE_OP_EXEC, IPE_HOOK_MPROTECT); + return ipe_evaluate_event(&ctx); + } + + return 0; +} + +/** + * ipe_kernel_read_file() - ipe security hook function for kernel read. + * @file: Supplies a pointer to the file structure being read in from disk. + * @id: Supplies the enumeration identifying the purpose of the read. + * @contents: Unused. + * + * This LSM hook is called when a file is read from disk in the kernel. + * + * Return: + * * %0 - Success + * * %-EACCES - Did not pass IPE policy + */ +int ipe_kernel_read_file(struct file *file, enum kernel_read_file_id id, + bool contents) +{ + struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT; + enum ipe_op_type op; + + switch (id) { + case READING_FIRMWARE: + op = IPE_OP_FIRMWARE; + break; + case READING_MODULE: + op = IPE_OP_KERNEL_MODULE; + break; + case READING_KEXEC_INITRAMFS: + op = IPE_OP_KEXEC_INITRAMFS; + break; + case READING_KEXEC_IMAGE: + op = IPE_OP_KEXEC_IMAGE; + break; + case READING_POLICY: + op = IPE_OP_POLICY; + break; + case READING_X509_CERTIFICATE: + op = IPE_OP_X509; + break; + default: + op = IPE_OP_INVALID; + WARN(1, "no rule setup for kernel_read_file enum %d", id); + } + + ipe_build_eval_ctx(&ctx, file, op, IPE_HOOK_KERNEL_READ); + return ipe_evaluate_event(&ctx); +} + +/** + * ipe_kernel_load_data() - ipe security hook function for kernel load data. + * @id: Supplies the enumeration identifying the purpose of the load. + * @contents: Unused. + * + * This LSM hook is called when a data buffer provided by userspace is loading + * into the kernel. + * + * Return: + * * %0 - Success + * * %-EACCES - Did not pass IPE policy + */ +int ipe_kernel_load_data(enum kernel_load_data_id id, bool contents) +{ + struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT; + enum ipe_op_type op; + + switch (id) { + case LOADING_FIRMWARE: + op = IPE_OP_FIRMWARE; + break; + case LOADING_MODULE: + op = IPE_OP_KERNEL_MODULE; + break; + case LOADING_KEXEC_INITRAMFS: + op = IPE_OP_KEXEC_INITRAMFS; + break; + case LOADING_KEXEC_IMAGE: + op = IPE_OP_KEXEC_IMAGE; + break; + case LOADING_POLICY: + op = IPE_OP_POLICY; + break; + case LOADING_X509_CERTIFICATE: + op = IPE_OP_X509; + break; + default: + op = IPE_OP_INVALID; + WARN(1, "no rule setup for kernel_load_data enum %d", id); + } + + ipe_build_eval_ctx(&ctx, NULL, op, IPE_HOOK_KERNEL_LOAD); + return ipe_evaluate_event(&ctx); +} + +/** + * ipe_unpack_initramfs() - Mark the current rootfs as initramfs. + */ +void ipe_unpack_initramfs(void) +{ + ipe_sb(current->fs->root.mnt->mnt_sb)->initramfs = true; +} + +#ifdef CONFIG_IPE_PROP_DM_VERITY +/** + * ipe_bdev_free_security() - Free IPE's LSM blob of block_devices. + * @bdev: Supplies a pointer to a block_device that contains the structure + * to free. + */ +void ipe_bdev_free_security(struct block_device *bdev) +{ + struct ipe_bdev *blob = ipe_bdev(bdev); + + ipe_digest_free(blob->root_hash); +} + +#ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE +static void ipe_set_dmverity_signature(struct ipe_bdev *blob, + const void *value, + size_t size) +{ + blob->dm_verity_signed = size > 0 && value; +} +#else +static inline void ipe_set_dmverity_signature(struct ipe_bdev *blob, + const void *value, + size_t size) +{ +} +#endif /* CONFIG_IPE_PROP_DM_VERITY_SIGNATURE */ + +/** + * ipe_bdev_setintegrity() - Save integrity data from a bdev to IPE's LSM blob. + * @bdev: Supplies a pointer to a block_device that contains the LSM blob. + * @type: Supplies the integrity type. + * @value: Supplies the value to store. + * @size: The size of @value. + * + * This hook is currently used to save dm-verity's root hash or the existence + * of a validated signed dm-verity root hash into LSM blob. + * + * Return: %0 on success. If an error occurs, the function will return the + * -errno. + */ +int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type type, + const void *value, size_t size) +{ + const struct dm_verity_digest *digest = NULL; + struct ipe_bdev *blob = ipe_bdev(bdev); + struct digest_info *info = NULL; + + if (type == LSM_INT_DMVERITY_SIG_VALID) { + ipe_set_dmverity_signature(blob, value, size); + + return 0; + } + + if (type != LSM_INT_DMVERITY_ROOTHASH) + return -EINVAL; + + if (!value) { + ipe_digest_free(blob->root_hash); + blob->root_hash = NULL; + + return 0; + } + digest = value; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + info->digest = kmemdup(digest->digest, digest->digest_len, GFP_KERNEL); + if (!info->digest) + goto err; + + info->alg = kstrdup(digest->alg, GFP_KERNEL); + if (!info->alg) + goto err; + + info->digest_len = digest->digest_len; + + ipe_digest_free(blob->root_hash); + blob->root_hash = info; + + return 0; +err: + ipe_digest_free(info); + + return -ENOMEM; +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +/** + * ipe_inode_setintegrity() - save integrity data from a inode to IPE's LSM blob. + * @inode: The inode to source the security blob from. + * @type: Supplies the integrity type. + * @value: The value to be stored. + * @size: The size of @value. + * + * This hook is currently used to save the existence of a validated fs-verity + * builtin signature into LSM blob. + * + * Return: %0 on success. If an error occurs, the function will return the + * -errno. + */ +int ipe_inode_setintegrity(const struct inode *inode, + enum lsm_integrity_type type, + const void *value, size_t size) +{ + struct ipe_inode *inode_sec = ipe_inode(inode); + + if (type == LSM_INT_FSVERITY_BUILTINSIG_VALID) { + inode_sec->fs_verity_signed = size > 0 && value; + return 0; + } + + return -EINVAL; +} +#endif /* CONFIG_CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ diff --git a/security/ipe/hooks.h b/security/ipe/hooks.h new file mode 100644 index 000000000000..38d4a387d039 --- /dev/null +++ b/security/ipe/hooks.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ +#ifndef _IPE_HOOKS_H +#define _IPE_HOOKS_H + +#include <linux/fs.h> +#include <linux/binfmts.h> +#include <linux/security.h> +#include <linux/blk_types.h> +#include <linux/fsverity.h> + +enum ipe_hook_type { + IPE_HOOK_BPRM_CHECK = 0, + IPE_HOOK_MMAP, + IPE_HOOK_MPROTECT, + IPE_HOOK_KERNEL_READ, + IPE_HOOK_KERNEL_LOAD, + __IPE_HOOK_MAX +}; + +#define IPE_HOOK_INVALID __IPE_HOOK_MAX + +int ipe_bprm_check_security(struct linux_binprm *bprm); + +int ipe_mmap_file(struct file *f, unsigned long reqprot, unsigned long prot, + unsigned long flags); + +int ipe_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot, + unsigned long prot); + +int ipe_kernel_read_file(struct file *file, enum kernel_read_file_id id, + bool contents); + +int ipe_kernel_load_data(enum kernel_load_data_id id, bool contents); + +void ipe_unpack_initramfs(void); + +#ifdef CONFIG_IPE_PROP_DM_VERITY +void ipe_bdev_free_security(struct block_device *bdev); + +int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type type, + const void *value, size_t len); +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +int ipe_inode_setintegrity(const struct inode *inode, enum lsm_integrity_type type, + const void *value, size_t size); +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ + +#endif /* _IPE_HOOKS_H */ diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c new file mode 100644 index 000000000000..4317134cb0da --- /dev/null +++ b/security/ipe/ipe.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ +#include <uapi/linux/lsm.h> + +#include "ipe.h" +#include "eval.h" +#include "hooks.h" + +extern const char *const ipe_boot_policy; +bool ipe_enabled; + +static struct lsm_blob_sizes ipe_blobs __ro_after_init = { + .lbs_superblock = sizeof(struct ipe_superblock), +#ifdef CONFIG_IPE_PROP_DM_VERITY + .lbs_bdev = sizeof(struct ipe_bdev), +#endif /* CONFIG_IPE_PROP_DM_VERITY */ +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG + .lbs_inode = sizeof(struct ipe_inode), +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ +}; + +static const struct lsm_id ipe_lsmid = { + .name = "ipe", + .id = LSM_ID_IPE, +}; + +struct ipe_superblock *ipe_sb(const struct super_block *sb) +{ + return sb->s_security + ipe_blobs.lbs_superblock; +} + +#ifdef CONFIG_IPE_PROP_DM_VERITY +struct ipe_bdev *ipe_bdev(struct block_device *b) +{ + return b->bd_security + ipe_blobs.lbs_bdev; +} +#endif /* CONFIG_IPE_PROP_DM_VERITY */ + +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +struct ipe_inode *ipe_inode(const struct inode *inode) +{ + return inode->i_security + ipe_blobs.lbs_inode; +} +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ + +static struct security_hook_list ipe_hooks[] __ro_after_init = { + LSM_HOOK_INIT(bprm_check_security, ipe_bprm_check_security), + LSM_HOOK_INIT(mmap_file, ipe_mmap_file), + LSM_HOOK_INIT(file_mprotect, ipe_file_mprotect), + LSM_HOOK_INIT(kernel_read_file, ipe_kernel_read_file), + LSM_HOOK_INIT(kernel_load_data, ipe_kernel_load_data), + LSM_HOOK_INIT(initramfs_populated, ipe_unpack_initramfs), +#ifdef CONFIG_IPE_PROP_DM_VERITY + LSM_HOOK_INIT(bdev_free_security, ipe_bdev_free_security), + LSM_HOOK_INIT(bdev_setintegrity, ipe_bdev_setintegrity), +#endif /* CONFIG_IPE_PROP_DM_VERITY */ +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG + LSM_HOOK_INIT(inode_setintegrity, ipe_inode_setintegrity), +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ +}; + +/** + * ipe_init() - Entry point of IPE. + * + * This is called at LSM init, which happens occurs early during kernel + * start up. During this phase, IPE registers its hooks and loads the + * builtin boot policy. + * + * Return: + * * %0 - OK + * * %-ENOMEM - Out of memory (OOM) + */ +static int __init ipe_init(void) +{ + struct ipe_policy *p = NULL; + + security_add_hooks(ipe_hooks, ARRAY_SIZE(ipe_hooks), &ipe_lsmid); + ipe_enabled = true; + + if (ipe_boot_policy) { + p = ipe_new_policy(ipe_boot_policy, strlen(ipe_boot_policy), + NULL, 0); + if (IS_ERR(p)) + return PTR_ERR(p); + + rcu_assign_pointer(ipe_active_policy, p); + } + + return 0; +} + +DEFINE_LSM(ipe) = { + .name = "ipe", + .init = ipe_init, + .blobs = &ipe_blobs, +}; diff --git a/security/ipe/ipe.h b/security/ipe/ipe.h new file mode 100644 index 000000000000..fb37513812dd --- /dev/null +++ b/security/ipe/ipe.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_H +#define _IPE_H + +#ifdef pr_fmt +#undef pr_fmt +#endif +#define pr_fmt(fmt) "ipe: " fmt + +#include <linux/lsm_hooks.h> +struct ipe_superblock *ipe_sb(const struct super_block *sb); + +extern bool ipe_enabled; + +#ifdef CONFIG_IPE_PROP_DM_VERITY +struct ipe_bdev *ipe_bdev(struct block_device *b); +#endif /* CONFIG_IPE_PROP_DM_VERITY */ +#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG +struct ipe_inode *ipe_inode(const struct inode *inode); +#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */ + +#endif /* _IPE_H */ diff --git a/security/ipe/policy.c b/security/ipe/policy.c new file mode 100644 index 000000000000..d8e7db857a2e --- /dev/null +++ b/security/ipe/policy.c @@ -0,0 +1,227 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include <linux/errno.h> +#include <linux/verification.h> + +#include "ipe.h" +#include "eval.h" +#include "fs.h" +#include "policy.h" +#include "policy_parser.h" +#include "audit.h" + +/* lock for synchronizing writers across ipe policy */ +DEFINE_MUTEX(ipe_policy_lock); + +/** + * ver_to_u64() - Convert an internal ipe_policy_version to a u64. + * @p: Policy to extract the version from. + * + * Bits (LSB is index 0): + * [48,32] -> Major + * [32,16] -> Minor + * [16, 0] -> Revision + * + * Return: u64 version of the embedded version structure. + */ +static inline u64 ver_to_u64(const struct ipe_policy *const p) +{ + u64 r; + + r = (((u64)p->parsed->version.major) << 32) + | (((u64)p->parsed->version.minor) << 16) + | ((u64)(p->parsed->version.rev)); + + return r; +} + +/** + * ipe_free_policy() - Deallocate a given IPE policy. + * @p: Supplies the policy to free. + * + * Safe to call on IS_ERR/NULL. + */ +void ipe_free_policy(struct ipe_policy *p) +{ + if (IS_ERR_OR_NULL(p)) + return; + + ipe_del_policyfs_node(p); + ipe_free_parsed_policy(p->parsed); + /* + * p->text is allocated only when p->pkcs7 is not NULL + * otherwise it points to the plaintext data inside the pkcs7 + */ + if (!p->pkcs7) + kfree(p->text); + kfree(p->pkcs7); + kfree(p); +} + +static int set_pkcs7_data(void *ctx, const void *data, size_t len, + size_t asn1hdrlen __always_unused) +{ + struct ipe_policy *p = ctx; + + p->text = (const char *)data; + p->textlen = len; + + return 0; +} + +/** + * ipe_update_policy() - parse a new policy and replace old with it. + * @root: Supplies a pointer to the securityfs inode saved the policy. + * @text: Supplies a pointer to the plain text policy. + * @textlen: Supplies the length of @text. + * @pkcs7: Supplies a pointer to a buffer containing a pkcs7 message. + * @pkcs7len: Supplies the length of @pkcs7len. + * + * @text/@textlen is mutually exclusive with @pkcs7/@pkcs7len - see + * ipe_new_policy. + * + * Context: Requires root->i_rwsem to be held. + * Return: %0 on success. If an error occurs, the function will return + * the -errno. + */ +int ipe_update_policy(struct inode *root, const char *text, size_t textlen, + const char *pkcs7, size_t pkcs7len) +{ + struct ipe_policy *old, *ap, *new = NULL; + int rc = 0; + + old = (struct ipe_policy *)root->i_private; + if (!old) + return -ENOENT; + + new = ipe_new_policy(text, textlen, pkcs7, pkcs7len); + if (IS_ERR(new)) + return PTR_ERR(new); + + if (strcmp(new->parsed->name, old->parsed->name)) { + rc = -EINVAL; + goto err; + } + + if (ver_to_u64(old) > ver_to_u64(new)) { + rc = -EINVAL; + goto err; + } + + root->i_private = new; + swap(new->policyfs, old->policyfs); + ipe_audit_policy_load(new); + + mutex_lock(&ipe_policy_lock); + ap = rcu_dereference_protected(ipe_active_policy, + lockdep_is_held(&ipe_policy_lock)); + if (old == ap) { + rcu_assign_pointer(ipe_active_policy, new); + mutex_unlock(&ipe_policy_lock); + ipe_audit_policy_activation(old, new); + } else { + mutex_unlock(&ipe_policy_lock); + } + synchronize_rcu(); + ipe_free_policy(old); + + return 0; +err: + ipe_free_policy(new); + return rc; +} + +/** + * ipe_new_policy() - Allocate and parse an ipe_policy structure. + * + * @text: Supplies a pointer to the plain-text policy to parse. + * @textlen: Supplies the length of @text. + * @pkcs7: Supplies a pointer to a pkcs7-signed IPE policy. + * @pkcs7len: Supplies the length of @pkcs7. + * + * @text/@textlen Should be NULL/0 if @pkcs7/@pkcs7len is set. + * + * Return: + * * a pointer to the ipe_policy structure - Success + * * %-EBADMSG - Policy is invalid + * * %-ENOMEM - Out of memory (OOM) + * * %-ERANGE - Policy version number overflow + * * %-EINVAL - Policy version parsing error + */ +struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, + const char *pkcs7, size_t pkcs7len) +{ + struct ipe_policy *new = NULL; + int rc = 0; + + new = kzalloc(sizeof(*new), GFP_KERNEL); + if (!new) + return ERR_PTR(-ENOMEM); + + if (!text) { + new->pkcs7len = pkcs7len; + new->pkcs7 = kmemdup(pkcs7, pkcs7len, GFP_KERNEL); + if (!new->pkcs7) { + rc = -ENOMEM; + goto err; + } + + rc = verify_pkcs7_signature(NULL, 0, new->pkcs7, pkcs7len, NULL, + VERIFYING_UNSPECIFIED_SIGNATURE, + set_pkcs7_data, new); + if (rc) + goto err; + } else { + new->textlen = textlen; + new->text = kstrdup(text, GFP_KERNEL); + if (!new->text) { + rc = -ENOMEM; + goto err; + } + } + + rc = ipe_parse_policy(new); + if (rc) + goto err; + + return new; +err: + ipe_free_policy(new); + return ERR_PTR(rc); +} + +/** + * ipe_set_active_pol() - Make @p the active policy. + * @p: Supplies a pointer to the policy to make active. + * + * Context: Requires root->i_rwsem, which i_private has the policy, to be held. + * Return: + * * %0 - Success + * * %-EINVAL - New active policy version is invalid + */ +int ipe_set_active_pol(const struct ipe_policy *p) +{ + struct ipe_policy *ap = NULL; + + mutex_lock(&ipe_policy_lock); + + ap = rcu_dereference_protected(ipe_active_policy, + lockdep_is_held(&ipe_policy_lock)); + if (ap == p) { + mutex_unlock(&ipe_policy_lock); + return 0; + } + if (ap && ver_to_u64(ap) > ver_to_u64(p)) { + mutex_unlock(&ipe_policy_lock); + return -EINVAL; + } + + rcu_assign_pointer(ipe_active_policy, p); + ipe_audit_policy_activation(ap, p); + mutex_unlock(&ipe_policy_lock); + + return 0; +} diff --git a/security/ipe/policy.h b/security/ipe/policy.h new file mode 100644 index 000000000000..5bfbdbddeef8 --- /dev/null +++ b/security/ipe/policy.h @@ -0,0 +1,98 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ +#ifndef _IPE_POLICY_H +#define _IPE_POLICY_H + +#include <linux/list.h> +#include <linux/types.h> +#include <linux/fs.h> + +enum ipe_op_type { + IPE_OP_EXEC = 0, + IPE_OP_FIRMWARE, + IPE_OP_KERNEL_MODULE, + IPE_OP_KEXEC_IMAGE, + IPE_OP_KEXEC_INITRAMFS, + IPE_OP_POLICY, + IPE_OP_X509, + __IPE_OP_MAX, +}; + +#define IPE_OP_INVALID __IPE_OP_MAX + +enum ipe_action_type { + IPE_ACTION_ALLOW = 0, + IPE_ACTION_DENY, + __IPE_ACTION_MAX +}; + +#define IPE_ACTION_INVALID __IPE_ACTION_MAX + +enum ipe_prop_type { + IPE_PROP_BOOT_VERIFIED_FALSE, + IPE_PROP_BOOT_VERIFIED_TRUE, + IPE_PROP_DMV_ROOTHASH, + IPE_PROP_DMV_SIG_FALSE, + IPE_PROP_DMV_SIG_TRUE, + IPE_PROP_FSV_DIGEST, + IPE_PROP_FSV_SIG_FALSE, + IPE_PROP_FSV_SIG_TRUE, + __IPE_PROP_MAX +}; + +#define IPE_PROP_INVALID __IPE_PROP_MAX + +struct ipe_prop { + struct list_head next; + enum ipe_prop_type type; + void *value; +}; + +struct ipe_rule { + enum ipe_op_type op; + enum ipe_action_type action; + struct list_head props; + struct list_head next; +}; + +struct ipe_op_table { + struct list_head rules; + enum ipe_action_type default_action; +}; + +struct ipe_parsed_policy { + const char *name; + struct { + u16 major; + u16 minor; + u16 rev; + } version; + + enum ipe_action_type global_default_action; + + struct ipe_op_table rules[__IPE_OP_MAX]; +}; + +struct ipe_policy { + const char *pkcs7; + size_t pkcs7len; + + const char *text; + size_t textlen; + + struct ipe_parsed_policy *parsed; + + struct dentry *policyfs; +}; + +struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, + const char *pkcs7, size_t pkcs7len); +void ipe_free_policy(struct ipe_policy *pol); +int ipe_update_policy(struct inode *root, const char *text, size_t textlen, + const char *pkcs7, size_t pkcs7len); +int ipe_set_active_pol(const struct ipe_policy *p); +extern struct mutex ipe_policy_lock; + +#endif /* _IPE_POLICY_H */ diff --git a/security/ipe/policy_fs.c b/security/ipe/policy_fs.c new file mode 100644 index 000000000000..3bcd8cbd09df --- /dev/null +++ b/security/ipe/policy_fs.c @@ -0,0 +1,472 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/types.h> +#include <linux/dcache.h> +#include <linux/security.h> + +#include "ipe.h" +#include "policy.h" +#include "eval.h" +#include "fs.h" + +#define MAX_VERSION_SIZE ARRAY_SIZE("65535.65535.65535") + +/** + * ipefs_file - defines a file in securityfs. + */ +struct ipefs_file { + const char *name; + umode_t access; + const struct file_operations *fops; +}; + +/** + * read_pkcs7() - Read handler for "ipe/policies/$name/pkcs7". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the pkcs7 blob representing the policy + * on success. If the policy is unsigned (like the boot policy), this + * will return -ENOENT. + * + * Return: + * * Length of buffer written - Success + * * %-ENOENT - Policy initializing/deleted or is unsigned + */ +static ssize_t read_pkcs7(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + const struct ipe_policy *p = NULL; + struct inode *root = NULL; + int rc = 0; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + if (!p->pkcs7) { + rc = -ENOENT; + goto out; + } + + rc = simple_read_from_buffer(data, len, offset, p->pkcs7, p->pkcs7len); + +out: + inode_unlock_shared(root); + + return rc; +} + +/** + * read_policy() - Read handler for "ipe/policies/$name/policy". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the plain-text version of the policy + * on success. + * + * Return: + * * Length of buffer written - Success + * * %-ENOENT - Policy initializing/deleted + */ +static ssize_t read_policy(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + const struct ipe_policy *p = NULL; + struct inode *root = NULL; + int rc = 0; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + rc = simple_read_from_buffer(data, len, offset, p->text, p->textlen); + +out: + inode_unlock_shared(root); + + return rc; +} + +/** + * read_name() - Read handler for "ipe/policies/$name/name". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the policy_name attribute on success. + * + * Return: + * * Length of buffer written - Success + * * %-ENOENT - Policy initializing/deleted + */ +static ssize_t read_name(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + const struct ipe_policy *p = NULL; + struct inode *root = NULL; + int rc = 0; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + rc = simple_read_from_buffer(data, len, offset, p->parsed->name, + strlen(p->parsed->name)); + +out: + inode_unlock_shared(root); + + return rc; +} + +/** + * read_version() - Read handler for "ipe/policies/$name/version". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the version string on success. + * + * Return: + * * Length of buffer written - Success + * * %-ENOENT - Policy initializing/deleted + */ +static ssize_t read_version(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + char buffer[MAX_VERSION_SIZE] = { 0 }; + const struct ipe_policy *p = NULL; + struct inode *root = NULL; + size_t strsize = 0; + ssize_t rc = 0; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + strsize = scnprintf(buffer, ARRAY_SIZE(buffer), "%hu.%hu.%hu", + p->parsed->version.major, p->parsed->version.minor, + p->parsed->version.rev); + + rc = simple_read_from_buffer(data, len, offset, buffer, strsize); + +out: + inode_unlock_shared(root); + + return rc; +} + +/** + * setactive() - Write handler for "ipe/policies/$name/active". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * Return: + * * Length of buffer written - Success + * * %-EPERM - Insufficient permission + * * %-EINVAL - Invalid input + * * %-ENOENT - Policy initializing/deleted + */ +static ssize_t setactive(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + const struct ipe_policy *p = NULL; + struct inode *root = NULL; + bool value = false; + int rc = 0; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + rc = kstrtobool_from_user(data, len, &value); + if (rc) + return rc; + + if (!value) + return -EINVAL; + + root = d_inode(f->f_path.dentry->d_parent); + inode_lock(root); + + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + rc = ipe_set_active_pol(p); + +out: + inode_unlock(root); + return (rc < 0) ? rc : len; +} + +/** + * getactive() - Read handler for "ipe/policies/$name/active". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the 1 or 0 depending on if the + * corresponding policy is active. + * + * Return: + * * Length of buffer written - Success + * * %-ENOENT - Policy initializing/deleted + */ +static ssize_t getactive(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + const struct ipe_policy *p = NULL; + struct inode *root = NULL; + const char *str; + int rc = 0; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + inode_unlock_shared(root); + return -ENOENT; + } + inode_unlock_shared(root); + + str = (p == rcu_access_pointer(ipe_active_policy)) ? "1" : "0"; + rc = simple_read_from_buffer(data, len, offset, str, 1); + + return rc; +} + +/** + * update_policy() - Write handler for "ipe/policies/$name/update". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * On success this updates the policy represented by $name, + * in-place. + * + * Return: Length of buffer written on success. If an error occurs, + * the function will return the -errno. + */ +static ssize_t update_policy(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + struct inode *root = NULL; + char *copy = NULL; + int rc = 0; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + copy = memdup_user(data, len); + if (IS_ERR(copy)) + return PTR_ERR(copy); + + root = d_inode(f->f_path.dentry->d_parent); + inode_lock(root); + rc = ipe_update_policy(root, NULL, 0, copy, len); + inode_unlock(root); + + kfree(copy); + if (rc) + return rc; + + return len; +} + +/** + * delete_policy() - write handler for "ipe/policies/$name/delete". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * On success this deletes the policy represented by $name. + * + * Return: + * * Length of buffer written - Success + * * %-EPERM - Insufficient permission/deleting active policy + * * %-EINVAL - Invalid input + * * %-ENOENT - Policy initializing/deleted + */ +static ssize_t delete_policy(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + struct ipe_policy *ap = NULL; + struct ipe_policy *p = NULL; + struct inode *root = NULL; + bool value = false; + int rc = 0; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + rc = kstrtobool_from_user(data, len, &value); + if (rc) + return rc; + + if (!value) + return -EINVAL; + + root = d_inode(f->f_path.dentry->d_parent); + inode_lock(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + inode_unlock(root); + return -ENOENT; + } + + mutex_lock(&ipe_policy_lock); + ap = rcu_dereference_protected(ipe_active_policy, + lockdep_is_held(&ipe_policy_lock)); + if (p == ap) { + mutex_unlock(&ipe_policy_lock); + inode_unlock(root); + return -EPERM; + } + mutex_unlock(&ipe_policy_lock); + + root->i_private = NULL; + inode_unlock(root); + + synchronize_rcu(); + ipe_free_policy(p); + + return len; +} + +static const struct file_operations content_fops = { + .read = read_policy, +}; + +static const struct file_operations pkcs7_fops = { + .read = read_pkcs7, +}; + +static const struct file_operations name_fops = { + .read = read_name, +}; + +static const struct file_operations ver_fops = { + .read = read_version, +}; + +static const struct file_operations active_fops = { + .write = setactive, + .read = getactive, +}; + +static const struct file_operations update_fops = { + .write = update_policy, +}; + +static const struct file_operations delete_fops = { + .write = delete_policy, +}; + +/** + * policy_subdir - files under a policy subdirectory + */ +static const struct ipefs_file policy_subdir[] = { + { "pkcs7", 0444, &pkcs7_fops }, + { "policy", 0444, &content_fops }, + { "name", 0444, &name_fops }, + { "version", 0444, &ver_fops }, + { "active", 0600, &active_fops }, + { "update", 0200, &update_fops }, + { "delete", 0200, &delete_fops }, +}; + +/** + * ipe_del_policyfs_node() - Delete a securityfs entry for @p. + * @p: Supplies a pointer to the policy to delete a securityfs entry for. + */ +void ipe_del_policyfs_node(struct ipe_policy *p) +{ + securityfs_recursive_remove(p->policyfs); + p->policyfs = NULL; +} + +/** + * ipe_new_policyfs_node() - Create a securityfs entry for @p. + * @p: Supplies a pointer to the policy to create a securityfs entry for. + * + * Return: %0 on success. If an error occurs, the function will return + * the -errno. + */ +int ipe_new_policyfs_node(struct ipe_policy *p) +{ + const struct ipefs_file *f = NULL; + struct dentry *policyfs = NULL; + struct inode *root = NULL; + struct dentry *d = NULL; + size_t i = 0; + int rc = 0; + + if (p->policyfs) + return 0; + + policyfs = securityfs_create_dir(p->parsed->name, policy_root); + if (IS_ERR(policyfs)) + return PTR_ERR(policyfs); + + root = d_inode(policyfs); + + for (i = 0; i < ARRAY_SIZE(policy_subdir); ++i) { + f = &policy_subdir[i]; + + d = securityfs_create_file(f->name, f->access, policyfs, + NULL, f->fops); + if (IS_ERR(d)) { + rc = PTR_ERR(d); + goto err; + } + } + + inode_lock(root); + p->policyfs = policyfs; + root->i_private = p; + inode_unlock(root); + + return 0; +err: + securityfs_recursive_remove(policyfs); + return rc; +} diff --git a/security/ipe/policy_parser.c b/security/ipe/policy_parser.c new file mode 100644 index 000000000000..7f27e39931d6 --- /dev/null +++ b/security/ipe/policy_parser.c @@ -0,0 +1,559 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/parser.h> +#include <linux/types.h> +#include <linux/ctype.h> + +#include "policy.h" +#include "policy_parser.h" +#include "digest.h" + +#define START_COMMENT '#' +#define IPE_POLICY_DELIM " \t" +#define IPE_LINE_DELIM "\n\r" + +/** + * new_parsed_policy() - Allocate and initialize a parsed policy. + * + * Return: + * * a pointer to the ipe_parsed_policy structure - Success + * * %-ENOMEM - Out of memory (OOM) + */ +static struct ipe_parsed_policy *new_parsed_policy(void) +{ + struct ipe_parsed_policy *p = NULL; + struct ipe_op_table *t = NULL; + size_t i = 0; + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return ERR_PTR(-ENOMEM); + + p->global_default_action = IPE_ACTION_INVALID; + + for (i = 0; i < ARRAY_SIZE(p->rules); ++i) { + t = &p->rules[i]; + + t->default_action = IPE_ACTION_INVALID; + INIT_LIST_HEAD(&t->rules); + } + + return p; +} + +/** + * remove_comment() - Truncate all chars following START_COMMENT in a string. + * + * @line: Supplies a policy line string for preprocessing. + */ +static void remove_comment(char *line) +{ + line = strchr(line, START_COMMENT); + + if (line) + *line = '\0'; +} + +/** + * remove_trailing_spaces() - Truncate all trailing spaces in a string. + * + * @line: Supplies a policy line string for preprocessing. + * + * Return: The length of truncated string. + */ +static size_t remove_trailing_spaces(char *line) +{ + size_t i = 0; + + i = strlen(line); + while (i > 0 && isspace(line[i - 1])) + i--; + + line[i] = '\0'; + + return i; +} + +/** + * parse_version() - Parse policy version. + * @ver: Supplies a version string to be parsed. + * @p: Supplies the partial parsed policy. + * + * Return: + * * %0 - Success + * * %-EBADMSG - Version string is invalid + * * %-ERANGE - Version number overflow + * * %-EINVAL - Parsing error + */ +static int parse_version(char *ver, struct ipe_parsed_policy *p) +{ + u16 *const cv[] = { &p->version.major, &p->version.minor, &p->version.rev }; + size_t sep_count = 0; + char *token; + int rc = 0; + + while ((token = strsep(&ver, ".")) != NULL) { + /* prevent overflow */ + if (sep_count >= ARRAY_SIZE(cv)) + return -EBADMSG; + + rc = kstrtou16(token, 10, cv[sep_count]); + if (rc) + return rc; + + ++sep_count; + } + + /* prevent underflow */ + if (sep_count != ARRAY_SIZE(cv)) + return -EBADMSG; + + return 0; +} + +enum header_opt { + IPE_HEADER_POLICY_NAME = 0, + IPE_HEADER_POLICY_VERSION, + __IPE_HEADER_MAX +}; + +static const match_table_t header_tokens = { + {IPE_HEADER_POLICY_NAME, "policy_name=%s"}, + {IPE_HEADER_POLICY_VERSION, "policy_version=%s"}, + {__IPE_HEADER_MAX, NULL} +}; + +/** + * parse_header() - Parse policy header information. + * @line: Supplies header line to be parsed. + * @p: Supplies the partial parsed policy. + * + * Return: + * * %0 - Success + * * %-EBADMSG - Header string is invalid + * * %-ENOMEM - Out of memory (OOM) + * * %-ERANGE - Version number overflow + * * %-EINVAL - Version parsing error + */ +static int parse_header(char *line, struct ipe_parsed_policy *p) +{ + substring_t args[MAX_OPT_ARGS]; + char *t, *ver = NULL; + size_t idx = 0; + int rc = 0; + + while ((t = strsep(&line, IPE_POLICY_DELIM)) != NULL) { + int token; + + if (*t == '\0') + continue; + if (idx >= __IPE_HEADER_MAX) { + rc = -EBADMSG; + goto out; + } + + token = match_token(t, header_tokens, args); + if (token != idx) { + rc = -EBADMSG; + goto out; + } + + switch (token) { + case IPE_HEADER_POLICY_NAME: + p->name = match_strdup(&args[0]); + if (!p->name) + rc = -ENOMEM; + break; + case IPE_HEADER_POLICY_VERSION: + ver = match_strdup(&args[0]); + if (!ver) { + rc = -ENOMEM; + break; + } + rc = parse_version(ver, p); + break; + default: + rc = -EBADMSG; + } + if (rc) + goto out; + ++idx; + } + + if (idx != __IPE_HEADER_MAX) + rc = -EBADMSG; + +out: + kfree(ver); + return rc; +} + +/** + * token_default() - Determine if the given token is "DEFAULT". + * @token: Supplies the token string to be compared. + * + * Return: + * * %false - The token is not "DEFAULT" + * * %true - The token is "DEFAULT" + */ +static bool token_default(char *token) +{ + return !strcmp(token, "DEFAULT"); +} + +/** + * free_rule() - Free the supplied ipe_rule struct. + * @r: Supplies the ipe_rule struct to be freed. + * + * Free a ipe_rule struct @r. Note @r must be removed from any lists before + * calling this function. + */ +static void free_rule(struct ipe_rule *r) +{ + struct ipe_prop *p, *t; + + if (IS_ERR_OR_NULL(r)) + return; + + list_for_each_entry_safe(p, t, &r->props, next) { + list_del(&p->next); + ipe_digest_free(p->value); + kfree(p); + } + + kfree(r); +} + +static const match_table_t operation_tokens = { + {IPE_OP_EXEC, "op=EXECUTE"}, + {IPE_OP_FIRMWARE, "op=FIRMWARE"}, + {IPE_OP_KERNEL_MODULE, "op=KMODULE"}, + {IPE_OP_KEXEC_IMAGE, "op=KEXEC_IMAGE"}, + {IPE_OP_KEXEC_INITRAMFS, "op=KEXEC_INITRAMFS"}, + {IPE_OP_POLICY, "op=POLICY"}, + {IPE_OP_X509, "op=X509_CERT"}, + {IPE_OP_INVALID, NULL} +}; + +/** + * parse_operation() - Parse the operation type given a token string. + * @t: Supplies the token string to be parsed. + * + * Return: The parsed operation type. + */ +static enum ipe_op_type parse_operation(char *t) +{ + substring_t args[MAX_OPT_ARGS]; + + return match_token(t, operation_tokens, args); +} + +static const match_table_t action_tokens = { + {IPE_ACTION_ALLOW, "action=ALLOW"}, + {IPE_ACTION_DENY, "action=DENY"}, + {IPE_ACTION_INVALID, NULL} +}; + +/** + * parse_action() - Parse the action type given a token string. + * @t: Supplies the token string to be parsed. + * + * Return: The parsed action type. + */ +static enum ipe_action_type parse_action(char *t) +{ + substring_t args[MAX_OPT_ARGS]; + + return match_token(t, action_tokens, args); +} + +static const match_table_t property_tokens = { + {IPE_PROP_BOOT_VERIFIED_FALSE, "boot_verified=FALSE"}, + {IPE_PROP_BOOT_VERIFIED_TRUE, "boot_verified=TRUE"}, + {IPE_PROP_DMV_ROOTHASH, "dmverity_roothash=%s"}, + {IPE_PROP_DMV_SIG_FALSE, "dmverity_signature=FALSE"}, + {IPE_PROP_DMV_SIG_TRUE, "dmverity_signature=TRUE"}, + {IPE_PROP_FSV_DIGEST, "fsverity_digest=%s"}, + {IPE_PROP_FSV_SIG_FALSE, "fsverity_signature=FALSE"}, + {IPE_PROP_FSV_SIG_TRUE, "fsverity_signature=TRUE"}, + {IPE_PROP_INVALID, NULL} +}; + +/** + * parse_property() - Parse a rule property given a token string. + * @t: Supplies the token string to be parsed. + * @r: Supplies the ipe_rule the parsed property will be associated with. + * + * This function parses and associates a property with an IPE rule based + * on a token string. + * + * Return: + * * %0 - Success + * * %-ENOMEM - Out of memory (OOM) + * * %-EBADMSG - The supplied token cannot be parsed + */ +static int parse_property(char *t, struct ipe_rule *r) +{ + substring_t args[MAX_OPT_ARGS]; + struct ipe_prop *p = NULL; + int rc = 0; + int token; + char *dup = NULL; + + p = kzalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return -ENOMEM; + + token = match_token(t, property_tokens, args); + + switch (token) { + case IPE_PROP_DMV_ROOTHASH: + case IPE_PROP_FSV_DIGEST: + dup = match_strdup(&args[0]); + if (!dup) { + rc = -ENOMEM; + goto err; + } + p->value = ipe_digest_parse(dup); + if (IS_ERR(p->value)) { + rc = PTR_ERR(p->value); + goto err; + } + fallthrough; + case IPE_PROP_BOOT_VERIFIED_FALSE: + case IPE_PROP_BOOT_VERIFIED_TRUE: + case IPE_PROP_DMV_SIG_FALSE: + case IPE_PROP_DMV_SIG_TRUE: + case IPE_PROP_FSV_SIG_FALSE: + case IPE_PROP_FSV_SIG_TRUE: + p->type = token; + break; + default: + rc = -EBADMSG; + break; + } + if (rc) + goto err; + list_add_tail(&p->next, &r->props); + +out: + kfree(dup); + return rc; +err: + kfree(p); + goto out; +} + +/** + * parse_rule() - parse a policy rule line. + * @line: Supplies rule line to be parsed. + * @p: Supplies the partial parsed policy. + * + * Return: + * * 0 - Success + * * %-ENOMEM - Out of memory (OOM) + * * %-EBADMSG - Policy syntax error + */ +static int parse_rule(char *line, struct ipe_parsed_policy *p) +{ + enum ipe_action_type action = IPE_ACTION_INVALID; + enum ipe_op_type op = IPE_OP_INVALID; + bool is_default_rule = false; + struct ipe_rule *r = NULL; + bool first_token = true; + bool op_parsed = false; + int rc = 0; + char *t; + + if (IS_ERR_OR_NULL(line)) + return -EBADMSG; + + r = kzalloc(sizeof(*r), GFP_KERNEL); + if (!r) + return -ENOMEM; + + INIT_LIST_HEAD(&r->next); + INIT_LIST_HEAD(&r->props); + + while (t = strsep(&line, IPE_POLICY_DELIM), line) { + if (*t == '\0') + continue; + if (first_token && token_default(t)) { + is_default_rule = true; + } else { + if (!op_parsed) { + op = parse_operation(t); + if (op == IPE_OP_INVALID) + rc = -EBADMSG; + else + op_parsed = true; + } else { + rc = parse_property(t, r); + } + } + + if (rc) + goto err; + first_token = false; + } + + action = parse_action(t); + if (action == IPE_ACTION_INVALID) { + rc = -EBADMSG; + goto err; + } + + if (is_default_rule) { + if (!list_empty(&r->props)) { + rc = -EBADMSG; + } else if (op == IPE_OP_INVALID) { + if (p->global_default_action != IPE_ACTION_INVALID) + rc = -EBADMSG; + else + p->global_default_action = action; + } else { + if (p->rules[op].default_action != IPE_ACTION_INVALID) + rc = -EBADMSG; + else + p->rules[op].default_action = action; + } + } else if (op != IPE_OP_INVALID && action != IPE_ACTION_INVALID) { + r->op = op; + r->action = action; + } else { + rc = -EBADMSG; + } + + if (rc) + goto err; + if (!is_default_rule) + list_add_tail(&r->next, &p->rules[op].rules); + else + free_rule(r); + + return rc; +err: + free_rule(r); + return rc; +} + +/** + * ipe_free_parsed_policy() - free a parsed policy structure. + * @p: Supplies the parsed policy. + */ +void ipe_free_parsed_policy(struct ipe_parsed_policy *p) +{ + struct ipe_rule *pp, *t; + size_t i = 0; + + if (IS_ERR_OR_NULL(p)) + return; + + for (i = 0; i < ARRAY_SIZE(p->rules); ++i) + list_for_each_entry_safe(pp, t, &p->rules[i].rules, next) { + list_del(&pp->next); + free_rule(pp); + } + + kfree(p->name); + kfree(p); +} + +/** + * validate_policy() - validate a parsed policy. + * @p: Supplies the fully parsed policy. + * + * Given a policy structure that was just parsed, validate that all + * operations have their default rules or a global default rule is set. + * + * Return: + * * %0 - Success + * * %-EBADMSG - Policy is invalid + */ +static int validate_policy(const struct ipe_parsed_policy *p) +{ + size_t i = 0; + + if (p->global_default_action != IPE_ACTION_INVALID) + return 0; + + for (i = 0; i < ARRAY_SIZE(p->rules); ++i) { + if (p->rules[i].default_action == IPE_ACTION_INVALID) + return -EBADMSG; + } + + return 0; +} + +/** + * ipe_parse_policy() - Given a string, parse the string into an IPE policy. + * @p: partially filled ipe_policy structure to populate with the result. + * it must have text and textlen set. + * + * Return: + * * %0 - Success + * * %-EBADMSG - Policy is invalid + * * %-ENOMEM - Out of Memory + * * %-ERANGE - Policy version number overflow + * * %-EINVAL - Policy version parsing error + */ +int ipe_parse_policy(struct ipe_policy *p) +{ + struct ipe_parsed_policy *pp = NULL; + char *policy = NULL, *dup = NULL; + bool header_parsed = false; + char *line = NULL; + size_t len; + int rc = 0; + + if (!p->textlen) + return -EBADMSG; + + policy = kmemdup_nul(p->text, p->textlen, GFP_KERNEL); + if (!policy) + return -ENOMEM; + dup = policy; + + pp = new_parsed_policy(); + if (IS_ERR(pp)) { + rc = PTR_ERR(pp); + goto out; + } + + while ((line = strsep(&policy, IPE_LINE_DELIM)) != NULL) { + remove_comment(line); + len = remove_trailing_spaces(line); + if (!len) + continue; + + if (!header_parsed) { + rc = parse_header(line, pp); + if (rc) + goto err; + header_parsed = true; + } else { + rc = parse_rule(line, pp); + if (rc) + goto err; + } + } + + if (!header_parsed || validate_policy(pp)) { + rc = -EBADMSG; + goto err; + } + + p->parsed = pp; + +out: + kfree(dup); + return rc; +err: + ipe_free_parsed_policy(pp); + goto out; +} diff --git a/security/ipe/policy_parser.h b/security/ipe/policy_parser.h new file mode 100644 index 000000000000..62b6209019a2 --- /dev/null +++ b/security/ipe/policy_parser.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ +#ifndef _IPE_POLICY_PARSER_H +#define _IPE_POLICY_PARSER_H + +int ipe_parse_policy(struct ipe_policy *p); +void ipe_free_parsed_policy(struct ipe_parsed_policy *p); + +#endif /* _IPE_POLICY_PARSER_H */ diff --git a/security/ipe/policy_tests.c b/security/ipe/policy_tests.c new file mode 100644 index 000000000000..89521f6b9994 --- /dev/null +++ b/security/ipe/policy_tests.c @@ -0,0 +1,296 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved. + */ + +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/list.h> +#include <kunit/test.h> +#include "policy.h" +struct policy_case { + const char *const policy; + int errno; + const char *const desc; +}; + +static const struct policy_case policy_cases[] = { + { + "policy_name=allowall policy_version=0.0.0\n" + "DEFAULT action=ALLOW", + 0, + "basic", + }, + { + "policy_name=trailing_comment policy_version=152.0.0 #This is comment\n" + "DEFAULT action=ALLOW", + 0, + "trailing comment", + }, + { + "policy_name=allowallnewline policy_version=0.2.0\n" + "DEFAULT action=ALLOW\n" + "\n", + 0, + "trailing newline", + }, + { + "policy_name=carriagereturnlinefeed policy_version=0.0.1\n" + "DEFAULT action=ALLOW\n" + "\r\n", + 0, + "clrf newline", + }, + { + "policy_name=whitespace policy_version=0.0.0\n" + "DEFAULT\taction=ALLOW\n" + " \t DEFAULT \t op=EXECUTE action=DENY\n" + "op=EXECUTE boot_verified=TRUE action=ALLOW\n" + "# this is a\tcomment\t\t\t\t\n" + "DEFAULT \t op=KMODULE\t\t\t action=DENY\r\n" + "op=KMODULE boot_verified=TRUE action=ALLOW\n", + 0, + "various whitespaces and nested default", + }, + { + "policy_name=boot_verified policy_version=-1236.0.0\n" + "DEFAULT\taction=ALLOW\n", + -EINVAL, + "negative version", + }, + { + "policy_name=$@!*&^%%\\:;{}() policy_version=0.0.0\n" + "DEFAULT action=ALLOW", + 0, + "special characters", + }, + { + "policy_name=test policy_version=999999.0.0\n" + "DEFAULT action=ALLOW", + -ERANGE, + "overflow version", + }, + { + "policy_name=test policy_version=255.0\n" + "DEFAULT action=ALLOW", + -EBADMSG, + "incomplete version", + }, + { + "policy_name=test policy_version=111.0.0.0\n" + "DEFAULT action=ALLOW", + -EBADMSG, + "extra version", + }, + { + "", + -EBADMSG, + "0-length policy", + }, + { + "policy_name=test\0policy_version=0.0.0\n" + "DEFAULT action=ALLOW", + -EBADMSG, + "random null in header", + }, + { + "policy_name=test policy_version=0.0.0\n" + "\0DEFAULT action=ALLOW", + -EBADMSG, + "incomplete policy from NULL", + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=DENY\n\0" + "op=EXECUTE dmverity_signature=TRUE action=ALLOW\n", + 0, + "NULL truncates policy", + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "op=EXECUTE dmverity_signature=abc action=ALLOW", + -EBADMSG, + "invalid property type", + }, + { + "DEFAULT action=ALLOW", + -EBADMSG, + "missing policy header", + }, + { + "policy_name=test policy_version=0.0.0\n", + -EBADMSG, + "missing default definition", + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "dmverity_signature=TRUE op=EXECUTE action=ALLOW", + -EBADMSG, + "invalid rule ordering" + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "action=ALLOW op=EXECUTE dmverity_signature=TRUE", + -EBADMSG, + "invalid rule ordering (2)", + }, + { + "policy_name=test policy_version=0.0\n" + "DEFAULT action=ALLOW\n" + "op=EXECUTE dmverity_signature=TRUE action=ALLOW", + -EBADMSG, + "invalid version", + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "op=UNKNOWN dmverity_signature=TRUE action=ALLOW", + -EBADMSG, + "unknown operation", + }, + { + "policy_name=asdvpolicy_version=0.0.0\n" + "DEFAULT action=ALLOW\n", + -EBADMSG, + "missing space after policy name", + }, + { + "policy_name=test\xFF\xEF policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "op=EXECUTE dmverity_signature=TRUE action=ALLOW", + 0, + "expanded ascii", + }, + { + "policy_name=test\xFF\xEF policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "op=EXECUTE dmverity_roothash=GOOD_DOG action=ALLOW", + -EBADMSG, + "invalid property value (2)", + }, + { + "policy_name=test policy_version=0.0.0\n" + "policy_name=test policy_version=0.1.0\n" + "DEFAULT action=ALLOW", + -EBADMSG, + "double header" + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "DEFAULT action=ALLOW\n", + -EBADMSG, + "double default" + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "DEFAULT op=EXECUTE action=DENY\n" + "DEFAULT op=EXECUTE action=ALLOW\n", + -EBADMSG, + "double operation default" + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "DEFAULT op=EXECUTE action=DEN\n", + -EBADMSG, + "invalid action value" + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "DEFAULT op=EXECUTE action\n", + -EBADMSG, + "invalid action value (2)" + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "UNKNOWN value=true\n", + -EBADMSG, + "unrecognized statement" + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "op=EXECUTE dmverity_roothash=1c0d7ee1f8343b7fbe418378e8eb22c061d7dec7 action=DENY\n", + -EBADMSG, + "old-style digest" + }, + { + "policy_name=test policy_version=0.0.0\n" + "DEFAULT action=ALLOW\n" + "op=EXECUTE fsverity_digest=1c0d7ee1f8343b7fbe418378e8eb22c061d7dec7 action=DENY\n", + -EBADMSG, + "old-style digest" + } +}; + +static void pol_to_desc(const struct policy_case *c, char *desc) +{ + strscpy(desc, c->desc, KUNIT_PARAM_DESC_SIZE); +} + +KUNIT_ARRAY_PARAM(ipe_policies, policy_cases, pol_to_desc); + +/** + * ipe_parser_unsigned_test - Test the parser by passing unsigned policies. + * @test: Supplies a pointer to a kunit structure. + * + * This is called by the kunit harness. This test does not check the correctness + * of the policy, but ensures that errors are handled correctly. + */ +static void ipe_parser_unsigned_test(struct kunit *test) +{ + const struct policy_case *p = test->param_value; + struct ipe_policy *pol; + + pol = ipe_new_policy(p->policy, strlen(p->policy), NULL, 0); + + if (p->errno) { + KUNIT_EXPECT_EQ(test, PTR_ERR(pol), p->errno); + return; + } + + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pol); + KUNIT_EXPECT_NOT_ERR_OR_NULL(test, pol->parsed); + KUNIT_EXPECT_STREQ(test, pol->text, p->policy); + KUNIT_EXPECT_PTR_EQ(test, NULL, pol->pkcs7); + KUNIT_EXPECT_EQ(test, 0, pol->pkcs7len); + + ipe_free_policy(pol); +} + +/** + * ipe_parser_widestring_test - Ensure parser fail on a wide string policy. + * @test: Supplies a pointer to a kunit structure. + * + * This is called by the kunit harness. + */ +static void ipe_parser_widestring_test(struct kunit *test) +{ + const unsigned short policy[] = L"policy_name=Test policy_version=0.0.0\n" + L"DEFAULT action=ALLOW"; + struct ipe_policy *pol = NULL; + + pol = ipe_new_policy((const char *)policy, (ARRAY_SIZE(policy) - 1) * 2, NULL, 0); + KUNIT_EXPECT_TRUE(test, IS_ERR_OR_NULL(pol)); + + ipe_free_policy(pol); +} + +static struct kunit_case ipe_parser_test_cases[] = { + KUNIT_CASE_PARAM(ipe_parser_unsigned_test, ipe_policies_gen_params), + KUNIT_CASE(ipe_parser_widestring_test), +}; + +static struct kunit_suite ipe_parser_test_suite = { + .name = "ipe-parser", + .test_cases = ipe_parser_test_cases, +}; + +kunit_test_suite(ipe_parser_test_suite); diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 7877a64cc6b8..0804f76a67be 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -1207,13 +1207,16 @@ static int current_check_refer_path(struct dentry *const old_dentry, /* Inode hooks */ -static void hook_inode_free_security(struct inode *const inode) +static void hook_inode_free_security_rcu(void *inode_security) { + struct landlock_inode_security *inode_sec; + /* * All inodes must already have been untied from their object by * release_inode() or hook_sb_delete(). */ - WARN_ON_ONCE(landlock_inode(inode)->object); + inode_sec = inode_security + landlock_blob_sizes.lbs_inode; + WARN_ON_ONCE(inode_sec->object); } /* Super-block hooks */ @@ -1637,7 +1640,7 @@ static int hook_file_ioctl_compat(struct file *file, unsigned int cmd, } static struct security_hook_list landlock_hooks[] __ro_after_init = { - LSM_HOOK_INIT(inode_free_security, hook_inode_free_security), + LSM_HOOK_INIT(inode_free_security_rcu, hook_inode_free_security_rcu), LSM_HOOK_INIT(sb_delete, hook_sb_delete), LSM_HOOK_INIT(sb_mount, hook_sb_mount), diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index cd84d8ea1dfb..f2bdbd55aa2b 100644 --- a/security/lockdown/lockdown.c +++ b/security/lockdown/lockdown.c @@ -76,7 +76,7 @@ static struct security_hook_list lockdown_hooks[] __ro_after_init = { LSM_HOOK_INIT(locked_down, lockdown_is_locked_down), }; -const struct lsm_id lockdown_lsmid = { +static const struct lsm_id lockdown_lsmid = { .name = "lockdown", .id = LSM_ID_LOCKDOWN, }; diff --git a/security/security.c b/security/security.c index 8cee5b6c6e6d..4564a0a1e4ef 100644 --- a/security/security.c +++ b/security/security.c @@ -28,30 +28,29 @@ #include <linux/xattr.h> #include <linux/msg.h> #include <linux/overflow.h> +#include <linux/perf_event.h> +#include <linux/fs.h> #include <net/flow.h> +#include <net/sock.h> -/* How many LSMs were built into the kernel? */ -#define LSM_COUNT (__end_lsm_info - __start_lsm_info) +#define SECURITY_HOOK_ACTIVE_KEY(HOOK, IDX) security_hook_active_##HOOK##_##IDX /* - * How many LSMs are built into the kernel as determined at - * build time. Used to determine fixed array sizes. - * The capability module is accounted for by CONFIG_SECURITY - */ -#define LSM_CONFIG_COUNT ( \ - (IS_ENABLED(CONFIG_SECURITY) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_TOMOYO) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_YAMA) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_LOADPIN) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_SAFESETID) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_SECURITY_LANDLOCK) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_IMA) ? 1 : 0) + \ - (IS_ENABLED(CONFIG_EVM) ? 1 : 0)) + * Identifier for the LSM static calls. + * HOOK is an LSM hook as defined in linux/lsm_hookdefs.h + * IDX is the index of the static call. 0 <= NUM < MAX_LSM_COUNT + */ +#define LSM_STATIC_CALL(HOOK, IDX) lsm_static_call_##HOOK##_##IDX + +/* + * Call the macro M for each LSM hook MAX_LSM_COUNT times. + */ +#define LSM_LOOP_UNROLL(M, ...) \ +do { \ + UNROLL(MAX_LSM_COUNT, M, __VA_ARGS__) \ +} while (0) + +#define LSM_DEFINE_UNROLL(M, ...) UNROLL(MAX_LSM_COUNT, M, __VA_ARGS__) /* * These are descriptions of the reasons that can be passed to the @@ -92,7 +91,6 @@ const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX + 1] = { [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality", }; -struct security_hook_heads security_hook_heads __ro_after_init; static BLOCKING_NOTIFIER_HEAD(blocking_lsm_notifier_chain); static struct kmem_cache *lsm_file_cache; @@ -108,9 +106,58 @@ static __initdata const char *chosen_major_lsm; static __initconst const char *const builtin_lsm_order = CONFIG_LSM; /* Ordered list of LSMs to initialize. */ -static __initdata struct lsm_info **ordered_lsms; +static __initdata struct lsm_info *ordered_lsms[MAX_LSM_COUNT + 1]; static __initdata struct lsm_info *exclusive; +#ifdef CONFIG_HAVE_STATIC_CALL +#define LSM_HOOK_TRAMP(NAME, NUM) \ + &STATIC_CALL_TRAMP(LSM_STATIC_CALL(NAME, NUM)) +#else +#define LSM_HOOK_TRAMP(NAME, NUM) NULL +#endif + +/* + * Define static calls and static keys for each LSM hook. + */ +#define DEFINE_LSM_STATIC_CALL(NUM, NAME, RET, ...) \ + DEFINE_STATIC_CALL_NULL(LSM_STATIC_CALL(NAME, NUM), \ + *((RET(*)(__VA_ARGS__))NULL)); \ + DEFINE_STATIC_KEY_FALSE(SECURITY_HOOK_ACTIVE_KEY(NAME, NUM)); + +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ + LSM_DEFINE_UNROLL(DEFINE_LSM_STATIC_CALL, NAME, RET, __VA_ARGS__) +#include <linux/lsm_hook_defs.h> +#undef LSM_HOOK +#undef DEFINE_LSM_STATIC_CALL + +/* + * Initialise a table of static calls for each LSM hook. + * DEFINE_STATIC_CALL_NULL invocation above generates a key (STATIC_CALL_KEY) + * and a trampoline (STATIC_CALL_TRAMP) which are used to call + * __static_call_update when updating the static call. + * + * The static calls table is used by early LSMs, some architectures can fault on + * unaligned accesses and the fault handling code may not be ready by then. + * Thus, the static calls table should be aligned to avoid any unhandled faults + * in early init. + */ +struct lsm_static_calls_table + static_calls_table __ro_after_init __aligned(sizeof(u64)) = { +#define INIT_LSM_STATIC_CALL(NUM, NAME) \ + (struct lsm_static_call) { \ + .key = &STATIC_CALL_KEY(LSM_STATIC_CALL(NAME, NUM)), \ + .trampoline = LSM_HOOK_TRAMP(NAME, NUM), \ + .active = &SECURITY_HOOK_ACTIVE_KEY(NAME, NUM), \ + }, +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ + .NAME = { \ + LSM_DEFINE_UNROLL(INIT_LSM_STATIC_CALL, NAME) \ + }, +#include <linux/lsm_hook_defs.h> +#undef LSM_HOOK +#undef INIT_LSM_STATIC_CALL + }; + static __initdata bool debug; #define init_debug(...) \ do { \ @@ -171,7 +218,7 @@ static void __init append_ordered_lsm(struct lsm_info *lsm, const char *from) if (exists_ordered_lsm(lsm)) return; - if (WARN(last_lsm == LSM_COUNT, "%s: out of LSM slots!?\n", from)) + if (WARN(last_lsm == MAX_LSM_COUNT, "%s: out of LSM static calls!?\n", from)) return; /* Enable this LSM, if it is not already set. */ @@ -218,6 +265,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed) lsm_set_blob_size(&needed->lbs_cred, &blob_sizes.lbs_cred); lsm_set_blob_size(&needed->lbs_file, &blob_sizes.lbs_file); + lsm_set_blob_size(&needed->lbs_ib, &blob_sizes.lbs_ib); /* * The inode blob gets an rcu_head in addition to * what the modules might need. @@ -226,11 +274,16 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed) blob_sizes.lbs_inode = sizeof(struct rcu_head); lsm_set_blob_size(&needed->lbs_inode, &blob_sizes.lbs_inode); lsm_set_blob_size(&needed->lbs_ipc, &blob_sizes.lbs_ipc); + lsm_set_blob_size(&needed->lbs_key, &blob_sizes.lbs_key); lsm_set_blob_size(&needed->lbs_msg_msg, &blob_sizes.lbs_msg_msg); + lsm_set_blob_size(&needed->lbs_perf_event, &blob_sizes.lbs_perf_event); + lsm_set_blob_size(&needed->lbs_sock, &blob_sizes.lbs_sock); lsm_set_blob_size(&needed->lbs_superblock, &blob_sizes.lbs_superblock); lsm_set_blob_size(&needed->lbs_task, &blob_sizes.lbs_task); + lsm_set_blob_size(&needed->lbs_tun_dev, &blob_sizes.lbs_tun_dev); lsm_set_blob_size(&needed->lbs_xattr_count, &blob_sizes.lbs_xattr_count); + lsm_set_blob_size(&needed->lbs_bdev, &blob_sizes.lbs_bdev); } /* Prepare LSM for initialization. */ @@ -268,7 +321,7 @@ static void __init initialize_lsm(struct lsm_info *lsm) * Current index to use while initializing the lsm id list. */ u32 lsm_active_cnt __ro_after_init; -const struct lsm_id *lsm_idlist[LSM_CONFIG_COUNT]; +const struct lsm_id *lsm_idlist[MAX_LSM_COUNT]; /* Populate ordered LSMs list from comma-separated LSM name list. */ static void __init ordered_lsm_parse(const char *order, const char *origin) @@ -350,6 +403,25 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) kfree(sep); } +static void __init lsm_static_call_init(struct security_hook_list *hl) +{ + struct lsm_static_call *scall = hl->scalls; + int i; + + for (i = 0; i < MAX_LSM_COUNT; i++) { + /* Update the first static call that is not used yet */ + if (!scall->hl) { + __static_call_update(scall->key, scall->trampoline, + hl->hook.lsm_func_addr); + scall->hl = hl; + static_branch_enable(scall->active); + return; + } + scall++; + } + panic("%s - Ran out of static slots.\n", __func__); +} + static void __init lsm_early_cred(struct cred *cred); static void __init lsm_early_task(struct task_struct *task); @@ -378,9 +450,6 @@ static void __init ordered_lsm_init(void) { struct lsm_info **lsm; - ordered_lsms = kcalloc(LSM_COUNT + 1, sizeof(*ordered_lsms), - GFP_KERNEL); - if (chosen_lsm_order) { if (chosen_major_lsm) { pr_warn("security=%s is ignored because it is superseded by lsm=%s\n", @@ -398,12 +467,20 @@ static void __init ordered_lsm_init(void) init_debug("cred blob size = %d\n", blob_sizes.lbs_cred); init_debug("file blob size = %d\n", blob_sizes.lbs_file); + init_debug("ib blob size = %d\n", blob_sizes.lbs_ib); init_debug("inode blob size = %d\n", blob_sizes.lbs_inode); init_debug("ipc blob size = %d\n", blob_sizes.lbs_ipc); +#ifdef CONFIG_KEYS + init_debug("key blob size = %d\n", blob_sizes.lbs_key); +#endif /* CONFIG_KEYS */ init_debug("msg_msg blob size = %d\n", blob_sizes.lbs_msg_msg); + init_debug("sock blob size = %d\n", blob_sizes.lbs_sock); init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock); + init_debug("perf event blob size = %d\n", blob_sizes.lbs_perf_event); init_debug("task blob size = %d\n", blob_sizes.lbs_task); + init_debug("tun device blob size = %d\n", blob_sizes.lbs_tun_dev); init_debug("xattr slots = %d\n", blob_sizes.lbs_xattr_count); + init_debug("bdev blob size = %d\n", blob_sizes.lbs_bdev); /* * Create any kmem_caches needed for blobs @@ -421,19 +498,12 @@ static void __init ordered_lsm_init(void) lsm_early_task(current); for (lsm = ordered_lsms; *lsm; lsm++) initialize_lsm(*lsm); - - kfree(ordered_lsms); } int __init early_security_init(void) { struct lsm_info *lsm; -#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ - INIT_HLIST_HEAD(&security_hook_heads.NAME); -#include "linux/lsm_hook_defs.h" -#undef LSM_HOOK - for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) { if (!lsm->enabled) lsm->enabled = &lsm_enabled_true; @@ -554,14 +624,14 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count, * Look at the previous entry, if there is one, for duplication. */ if (lsm_active_cnt == 0 || lsm_idlist[lsm_active_cnt - 1] != lsmid) { - if (lsm_active_cnt >= LSM_CONFIG_COUNT) + if (lsm_active_cnt >= MAX_LSM_COUNT) panic("%s Too many LSMs registered.\n", __func__); lsm_idlist[lsm_active_cnt++] = lsmid; } for (i = 0; i < count; i++) { hooks[i].lsmid = lsmid; - hlist_add_tail_rcu(&hooks[i].list, hooks[i].head); + lsm_static_call_init(&hooks[i]); } /* @@ -596,28 +666,43 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb) EXPORT_SYMBOL(unregister_blocking_lsm_notifier); /** - * lsm_cred_alloc - allocate a composite cred blob - * @cred: the cred that needs a blob + * lsm_blob_alloc - allocate a composite blob + * @dest: the destination for the blob + * @size: the size of the blob * @gfp: allocation type * - * Allocate the cred blob for all the modules + * Allocate a blob for all the modules * * Returns 0, or -ENOMEM if memory can't be allocated. */ -static int lsm_cred_alloc(struct cred *cred, gfp_t gfp) +static int lsm_blob_alloc(void **dest, size_t size, gfp_t gfp) { - if (blob_sizes.lbs_cred == 0) { - cred->security = NULL; + if (size == 0) { + *dest = NULL; return 0; } - cred->security = kzalloc(blob_sizes.lbs_cred, gfp); - if (cred->security == NULL) + *dest = kzalloc(size, gfp); + if (*dest == NULL) return -ENOMEM; return 0; } /** + * lsm_cred_alloc - allocate a composite cred blob + * @cred: the cred that needs a blob + * @gfp: allocation type + * + * Allocate the cred blob for all the modules + * + * Returns 0, or -ENOMEM if memory can't be allocated. + */ +static int lsm_cred_alloc(struct cred *cred, gfp_t gfp) +{ + return lsm_blob_alloc(&cred->security, blob_sizes.lbs_cred, gfp); +} + +/** * lsm_early_cred - during initialization allocate a composite cred blob * @cred: the cred that needs a blob * @@ -660,7 +745,7 @@ static int lsm_file_alloc(struct file *file) * * Returns 0, or -ENOMEM if memory can't be allocated. */ -int lsm_inode_alloc(struct inode *inode) +static int lsm_inode_alloc(struct inode *inode) { if (!lsm_inode_cache) { inode->i_security = NULL; @@ -683,15 +768,7 @@ int lsm_inode_alloc(struct inode *inode) */ static int lsm_task_alloc(struct task_struct *task) { - if (blob_sizes.lbs_task == 0) { - task->security = NULL; - return 0; - } - - task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL); - if (task->security == NULL) - return -ENOMEM; - return 0; + return lsm_blob_alloc(&task->security, blob_sizes.lbs_task, GFP_KERNEL); } /** @@ -704,16 +781,23 @@ static int lsm_task_alloc(struct task_struct *task) */ static int lsm_ipc_alloc(struct kern_ipc_perm *kip) { - if (blob_sizes.lbs_ipc == 0) { - kip->security = NULL; - return 0; - } + return lsm_blob_alloc(&kip->security, blob_sizes.lbs_ipc, GFP_KERNEL); +} - kip->security = kzalloc(blob_sizes.lbs_ipc, GFP_KERNEL); - if (kip->security == NULL) - return -ENOMEM; - return 0; +#ifdef CONFIG_KEYS +/** + * lsm_key_alloc - allocate a composite key blob + * @key: the key that needs a blob + * + * Allocate the key blob for all the modules + * + * Returns 0, or -ENOMEM if memory can't be allocated. + */ +static int lsm_key_alloc(struct key *key) +{ + return lsm_blob_alloc(&key->security, blob_sizes.lbs_key, GFP_KERNEL); } +#endif /* CONFIG_KEYS */ /** * lsm_msg_msg_alloc - allocate a composite msg_msg blob @@ -725,14 +809,29 @@ static int lsm_ipc_alloc(struct kern_ipc_perm *kip) */ static int lsm_msg_msg_alloc(struct msg_msg *mp) { - if (blob_sizes.lbs_msg_msg == 0) { - mp->security = NULL; + return lsm_blob_alloc(&mp->security, blob_sizes.lbs_msg_msg, + GFP_KERNEL); +} + +/** + * lsm_bdev_alloc - allocate a composite block_device blob + * @bdev: the block_device that needs a blob + * + * Allocate the block_device blob for all the modules + * + * Returns 0, or -ENOMEM if memory can't be allocated. + */ +static int lsm_bdev_alloc(struct block_device *bdev) +{ + if (blob_sizes.lbs_bdev == 0) { + bdev->bd_security = NULL; return 0; } - mp->security = kzalloc(blob_sizes.lbs_msg_msg, GFP_KERNEL); - if (mp->security == NULL) + bdev->bd_security = kzalloc(blob_sizes.lbs_bdev, GFP_KERNEL); + if (!bdev->bd_security) return -ENOMEM; + return 0; } @@ -760,15 +859,8 @@ static void __init lsm_early_task(struct task_struct *task) */ static int lsm_superblock_alloc(struct super_block *sb) { - if (blob_sizes.lbs_superblock == 0) { - sb->s_security = NULL; - return 0; - } - - sb->s_security = kzalloc(blob_sizes.lbs_superblock, GFP_KERNEL); - if (sb->s_security == NULL) - return -ENOMEM; - return 0; + return lsm_blob_alloc(&sb->s_security, blob_sizes.lbs_superblock, + GFP_KERNEL); } /** @@ -853,29 +945,43 @@ out: * call_int_hook: * This is a hook that returns a value. */ +#define __CALL_STATIC_VOID(NUM, HOOK, ...) \ +do { \ + if (static_branch_unlikely(&SECURITY_HOOK_ACTIVE_KEY(HOOK, NUM))) { \ + static_call(LSM_STATIC_CALL(HOOK, NUM))(__VA_ARGS__); \ + } \ +} while (0); -#define call_void_hook(FUNC, ...) \ - do { \ - struct security_hook_list *P; \ - \ - hlist_for_each_entry(P, &security_hook_heads.FUNC, list) \ - P->hook.FUNC(__VA_ARGS__); \ +#define call_void_hook(HOOK, ...) \ + do { \ + LSM_LOOP_UNROLL(__CALL_STATIC_VOID, HOOK, __VA_ARGS__); \ } while (0) -#define call_int_hook(FUNC, ...) ({ \ - int RC = LSM_RET_DEFAULT(FUNC); \ - do { \ - struct security_hook_list *P; \ - \ - hlist_for_each_entry(P, &security_hook_heads.FUNC, list) { \ - RC = P->hook.FUNC(__VA_ARGS__); \ - if (RC != LSM_RET_DEFAULT(FUNC)) \ - break; \ - } \ - } while (0); \ - RC; \ + +#define __CALL_STATIC_INT(NUM, R, HOOK, LABEL, ...) \ +do { \ + if (static_branch_unlikely(&SECURITY_HOOK_ACTIVE_KEY(HOOK, NUM))) { \ + R = static_call(LSM_STATIC_CALL(HOOK, NUM))(__VA_ARGS__); \ + if (R != LSM_RET_DEFAULT(HOOK)) \ + goto LABEL; \ + } \ +} while (0); + +#define call_int_hook(HOOK, ...) \ +({ \ + __label__ OUT; \ + int RC = LSM_RET_DEFAULT(HOOK); \ + \ + LSM_LOOP_UNROLL(__CALL_STATIC_INT, RC, HOOK, OUT, __VA_ARGS__); \ +OUT: \ + RC; \ }) +#define lsm_for_each_hook(scall, NAME) \ + for (scall = static_calls_table.NAME; \ + scall - static_calls_table.NAME < MAX_LSM_COUNT; scall++) \ + if (static_key_enabled(&scall->active->key)) + /* Security operations */ /** @@ -1110,20 +1216,19 @@ int security_settime64(const struct timespec64 *ts, const struct timezone *tz) */ int security_vm_enough_memory_mm(struct mm_struct *mm, long pages) { - struct security_hook_list *hp; + struct lsm_static_call *scall; int cap_sys_admin = 1; int rc; /* - * The module will respond with a positive value if - * it thinks the __vm_enough_memory() call should be - * made with the cap_sys_admin set. If all of the modules - * agree that it should be set it will. If any module - * thinks it should not be set it won't. + * The module will respond with 0 if it thinks the __vm_enough_memory() + * call should be made with the cap_sys_admin set. If all of the modules + * agree that it should be set it will. If any module thinks it should + * not be set it won't. */ - hlist_for_each_entry(hp, &security_hook_heads.vm_enough_memory, list) { - rc = hp->hook.vm_enough_memory(mm, pages); - if (rc <= 0) { + lsm_for_each_hook(scall, vm_enough_memory) { + rc = scall->hl->hook.vm_enough_memory(mm, pages); + if (rc < 0) { cap_sys_admin = 0; break; } @@ -1269,13 +1374,12 @@ int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc) int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param) { - struct security_hook_list *hp; + struct lsm_static_call *scall; int trc; int rc = -ENOPARAM; - hlist_for_each_entry(hp, &security_hook_heads.fs_context_parse_param, - list) { - trc = hp->hook.fs_context_parse_param(fc, param); + lsm_for_each_hook(scall, fs_context_parse_param) { + trc = scall->hl->hook.fs_context_parse_param(fc, param); if (trc == 0) rc = 0; else if (trc != -ENOPARAM) @@ -1505,12 +1609,11 @@ int security_sb_set_mnt_opts(struct super_block *sb, unsigned long kern_flags, unsigned long *set_kern_flags) { - struct security_hook_list *hp; + struct lsm_static_call *scall; int rc = mnt_opts ? -EOPNOTSUPP : LSM_RET_DEFAULT(sb_set_mnt_opts); - hlist_for_each_entry(hp, &security_hook_heads.sb_set_mnt_opts, - list) { - rc = hp->hook.sb_set_mnt_opts(sb, mnt_opts, kern_flags, + lsm_for_each_hook(scall, sb_set_mnt_opts) { + rc = scall->hl->hook.sb_set_mnt_opts(sb, mnt_opts, kern_flags, set_kern_flags); if (rc != LSM_RET_DEFAULT(sb_set_mnt_opts)) break; @@ -1596,9 +1699,8 @@ int security_inode_alloc(struct inode *inode) static void inode_free_by_rcu(struct rcu_head *head) { - /* - * The rcu head is at the start of the inode blob - */ + /* The rcu head is at the start of the inode blob */ + call_void_hook(inode_free_security_rcu, head); kmem_cache_free(lsm_inode_cache, head); } @@ -1606,23 +1708,24 @@ static void inode_free_by_rcu(struct rcu_head *head) * security_inode_free() - Free an inode's LSM blob * @inode: the inode * - * Deallocate the inode security structure and set @inode->i_security to NULL. + * Release any LSM resources associated with @inode, although due to the + * inode's RCU protections it is possible that the resources will not be + * fully released until after the current RCU grace period has elapsed. + * + * It is important for LSMs to note that despite being present in a call to + * security_inode_free(), @inode may still be referenced in a VFS path walk + * and calls to security_inode_permission() may be made during, or after, + * a call to security_inode_free(). For this reason the inode->i_security + * field is released via a call_rcu() callback and any LSMs which need to + * retain inode state for use in security_inode_permission() should only + * release that state in the inode_free_security_rcu() LSM hook callback. */ void security_inode_free(struct inode *inode) { call_void_hook(inode_free_security, inode); - /* - * The inode may still be referenced in a path walk and - * a call to security_inode_permission() can be made - * after inode_free_security() is called. Ideally, the VFS - * wouldn't do this, but fixing that is a much harder - * job. For now, simply free the i_security via RCU, and - * leave the current inode->i_security pointer intact. - * The inode will be freed after the RCU grace period too. - */ - if (inode->i_security) - call_rcu((struct rcu_head *)inode->i_security, - inode_free_by_rcu); + if (!inode->i_security) + return; + call_rcu((struct rcu_head *)inode->i_security, inode_free_by_rcu); } /** @@ -1705,7 +1808,7 @@ int security_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, const initxattrs initxattrs, void *fs_data) { - struct security_hook_list *hp; + struct lsm_static_call *scall; struct xattr *new_xattrs = NULL; int ret = -EOPNOTSUPP, xattr_count = 0; @@ -1723,9 +1826,8 @@ int security_inode_init_security(struct inode *inode, struct inode *dir, return -ENOMEM; } - hlist_for_each_entry(hp, &security_hook_heads.inode_init_security, - list) { - ret = hp->hook.inode_init_security(inode, dir, qstr, new_xattrs, + lsm_for_each_hook(scall, inode_init_security) { + ret = scall->hl->hook.inode_init_security(inode, dir, qstr, new_xattrs, &xattr_count); if (ret && ret != -EOPNOTSUPP) goto out; @@ -2661,19 +2763,14 @@ EXPORT_SYMBOL(security_inode_copy_up); * lower layer to the union/overlay layer. The caller is responsible for * reading and writing the xattrs, this hook is merely a filter. * - * Return: Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP - * if the security module does not know about attribute, or a negative - * error code to abort the copy up. + * Return: Returns 0 to accept the xattr, -ECANCELED to discard the xattr, + * -EOPNOTSUPP if the security module does not know about attribute, + * or a negative error code to abort the copy up. */ int security_inode_copy_up_xattr(struct dentry *src, const char *name) { int rc; - /* - * The implementation can return 0 (accept the xattr), 1 (discard the - * xattr), -EOPNOTSUPP if it does not know anything about the xattr or - * any other error code in case of an error. - */ rc = call_int_hook(inode_copy_up_xattr, src, name); if (rc != LSM_RET_DEFAULT(inode_copy_up_xattr)) return rc; @@ -2683,6 +2780,26 @@ int security_inode_copy_up_xattr(struct dentry *src, const char *name) EXPORT_SYMBOL(security_inode_copy_up_xattr); /** + * security_inode_setintegrity() - Set the inode's integrity data + * @inode: inode + * @type: type of integrity, e.g. hash digest, signature, etc + * @value: the integrity value + * @size: size of the integrity value + * + * Register a verified integrity measurement of a inode with LSMs. + * LSMs should free the previously saved data if @value is NULL. + * + * Return: Returns 0 on success, negative values on failure. + */ +int security_inode_setintegrity(const struct inode *inode, + enum lsm_integrity_type type, const void *value, + size_t size) +{ + return call_int_hook(inode_setintegrity, inode, type, value, size); +} +EXPORT_SYMBOL(security_inode_setintegrity); + +/** * security_kernfs_init_security() - Init LSM context for a kernfs node * @kn_dir: parent kernfs node * @kn: the kernfs node to initialize @@ -2931,6 +3048,8 @@ int security_file_fcntl(struct file *file, unsigned int cmd, unsigned long arg) * Save owner security information (typically from current->security) in * file->f_security for later use by the send_sigiotask hook. * + * This hook is called with file->f_owner.lock held. + * * Return: Returns 0 on success. */ void security_file_set_fowner(struct file *file) @@ -3557,10 +3676,10 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3, { int thisrc; int rc = LSM_RET_DEFAULT(task_prctl); - struct security_hook_list *hp; + struct lsm_static_call *scall; - hlist_for_each_entry(hp, &security_hook_heads.task_prctl, list) { - thisrc = hp->hook.task_prctl(option, arg2, arg3, arg4, arg5); + lsm_for_each_hook(scall, task_prctl) { + thisrc = scall->hl->hook.task_prctl(option, arg2, arg3, arg4, arg5); if (thisrc != LSM_RET_DEFAULT(task_prctl)) { rc = thisrc; if (thisrc != 0) @@ -3966,7 +4085,7 @@ EXPORT_SYMBOL(security_d_instantiate); int security_getselfattr(unsigned int attr, struct lsm_ctx __user *uctx, u32 __user *size, u32 flags) { - struct security_hook_list *hp; + struct lsm_static_call *scall; struct lsm_ctx lctx = { .id = LSM_ID_UNDEF, }; u8 __user *base = (u8 __user *)uctx; u32 entrysize; @@ -4004,13 +4123,13 @@ int security_getselfattr(unsigned int attr, struct lsm_ctx __user *uctx, * In the usual case gather all the data from the LSMs. * In the single case only get the data from the LSM specified. */ - hlist_for_each_entry(hp, &security_hook_heads.getselfattr, list) { - if (single && lctx.id != hp->lsmid->id) + lsm_for_each_hook(scall, getselfattr) { + if (single && lctx.id != scall->hl->lsmid->id) continue; entrysize = left; if (base) uctx = (struct lsm_ctx __user *)(base + total); - rc = hp->hook.getselfattr(attr, uctx, &entrysize, flags); + rc = scall->hl->hook.getselfattr(attr, uctx, &entrysize, flags); if (rc == -EOPNOTSUPP) { rc = 0; continue; @@ -4059,7 +4178,7 @@ int security_getselfattr(unsigned int attr, struct lsm_ctx __user *uctx, int security_setselfattr(unsigned int attr, struct lsm_ctx __user *uctx, u32 size, u32 flags) { - struct security_hook_list *hp; + struct lsm_static_call *scall; struct lsm_ctx *lctx; int rc = LSM_RET_DEFAULT(setselfattr); u64 required_len; @@ -4082,9 +4201,9 @@ int security_setselfattr(unsigned int attr, struct lsm_ctx __user *uctx, goto free_out; } - hlist_for_each_entry(hp, &security_hook_heads.setselfattr, list) - if ((hp->lsmid->id) == lctx->id) { - rc = hp->hook.setselfattr(attr, lctx, size, flags); + lsm_for_each_hook(scall, setselfattr) + if ((scall->hl->lsmid->id) == lctx->id) { + rc = scall->hl->hook.setselfattr(attr, lctx, size, flags); break; } @@ -4107,12 +4226,12 @@ free_out: int security_getprocattr(struct task_struct *p, int lsmid, const char *name, char **value) { - struct security_hook_list *hp; + struct lsm_static_call *scall; - hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) { - if (lsmid != 0 && lsmid != hp->lsmid->id) + lsm_for_each_hook(scall, getprocattr) { + if (lsmid != 0 && lsmid != scall->hl->lsmid->id) continue; - return hp->hook.getprocattr(p, name, value); + return scall->hl->hook.getprocattr(p, name, value); } return LSM_RET_DEFAULT(getprocattr); } @@ -4131,12 +4250,12 @@ int security_getprocattr(struct task_struct *p, int lsmid, const char *name, */ int security_setprocattr(int lsmid, const char *name, void *value, size_t size) { - struct security_hook_list *hp; + struct lsm_static_call *scall; - hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) { - if (lsmid != 0 && lsmid != hp->lsmid->id) + lsm_for_each_hook(scall, setprocattr) { + if (lsmid != 0 && lsmid != scall->hl->lsmid->id) continue; - return hp->hook.setprocattr(name, value, size); + return scall->hl->hook.setprocattr(name, value, size); } return LSM_RET_DEFAULT(setprocattr); } @@ -4674,6 +4793,20 @@ int security_socket_getpeersec_dgram(struct socket *sock, EXPORT_SYMBOL(security_socket_getpeersec_dgram); /** + * lsm_sock_alloc - allocate a composite sock blob + * @sock: the sock that needs a blob + * @gfp: allocation mode + * + * Allocate the sock blob for all the modules + * + * Returns 0, or -ENOMEM if memory can't be allocated. + */ +static int lsm_sock_alloc(struct sock *sock, gfp_t gfp) +{ + return lsm_blob_alloc(&sock->sk_security, blob_sizes.lbs_sock, gfp); +} + +/** * security_sk_alloc() - Allocate and initialize a sock's LSM blob * @sk: sock * @family: protocol family @@ -4686,7 +4819,14 @@ EXPORT_SYMBOL(security_socket_getpeersec_dgram); */ int security_sk_alloc(struct sock *sk, int family, gfp_t priority) { - return call_int_hook(sk_alloc_security, sk, family, priority); + int rc = lsm_sock_alloc(sk, priority); + + if (unlikely(rc)) + return rc; + rc = call_int_hook(sk_alloc_security, sk, family, priority); + if (unlikely(rc)) + security_sk_free(sk); + return rc; } /** @@ -4698,6 +4838,8 @@ int security_sk_alloc(struct sock *sk, int family, gfp_t priority) void security_sk_free(struct sock *sk) { call_void_hook(sk_free_security, sk); + kfree(sk->sk_security); + sk->sk_security = NULL; } /** @@ -4845,7 +4987,18 @@ EXPORT_SYMBOL(security_secmark_refcount_dec); */ int security_tun_dev_alloc_security(void **security) { - return call_int_hook(tun_dev_alloc_security, security); + int rc; + + rc = lsm_blob_alloc(security, blob_sizes.lbs_tun_dev, GFP_KERNEL); + if (rc) + return rc; + + rc = call_int_hook(tun_dev_alloc_security, *security); + if (rc) { + kfree(*security); + *security = NULL; + } + return rc; } EXPORT_SYMBOL(security_tun_dev_alloc_security); @@ -4857,7 +5010,7 @@ EXPORT_SYMBOL(security_tun_dev_alloc_security); */ void security_tun_dev_free_security(void *security) { - call_void_hook(tun_dev_free_security, security); + kfree(security); } EXPORT_SYMBOL(security_tun_dev_free_security); @@ -5053,7 +5206,18 @@ EXPORT_SYMBOL(security_ib_endport_manage_subnet); */ int security_ib_alloc_security(void **sec) { - return call_int_hook(ib_alloc_security, sec); + int rc; + + rc = lsm_blob_alloc(sec, blob_sizes.lbs_ib, GFP_KERNEL); + if (rc) + return rc; + + rc = call_int_hook(ib_alloc_security, *sec); + if (rc) { + kfree(*sec); + *sec = NULL; + } + return rc; } EXPORT_SYMBOL(security_ib_alloc_security); @@ -5065,7 +5229,7 @@ EXPORT_SYMBOL(security_ib_alloc_security); */ void security_ib_free_security(void *sec) { - call_void_hook(ib_free_security, sec); + kfree(sec); } EXPORT_SYMBOL(security_ib_free_security); #endif /* CONFIG_SECURITY_INFINIBAND */ @@ -5223,7 +5387,7 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy *xp, const struct flowi_common *flic) { - struct security_hook_list *hp; + struct lsm_static_call *scall; int rc = LSM_RET_DEFAULT(xfrm_state_pol_flow_match); /* @@ -5235,9 +5399,8 @@ int security_xfrm_state_pol_flow_match(struct xfrm_state *x, * For speed optimization, we explicitly break the loop rather than * using the macro */ - hlist_for_each_entry(hp, &security_hook_heads.xfrm_state_pol_flow_match, - list) { - rc = hp->hook.xfrm_state_pol_flow_match(x, xp, flic); + lsm_for_each_hook(scall, xfrm_state_pol_flow_match) { + rc = scall->hl->hook.xfrm_state_pol_flow_match(x, xp, flic); break; } return rc; @@ -5282,7 +5445,14 @@ EXPORT_SYMBOL(security_skb_classify_flow); int security_key_alloc(struct key *key, const struct cred *cred, unsigned long flags) { - return call_int_hook(key_alloc, key, cred, flags); + int rc = lsm_key_alloc(key); + + if (unlikely(rc)) + return rc; + rc = call_int_hook(key_alloc, key, cred, flags); + if (unlikely(rc)) + security_key_free(key); + return rc; } /** @@ -5293,7 +5463,8 @@ int security_key_alloc(struct key *key, const struct cred *cred, */ void security_key_free(struct key *key) { - call_void_hook(key_free, key); + kfree(key->security); + key->security = NULL; } /** @@ -5596,6 +5767,85 @@ int security_locked_down(enum lockdown_reason what) } EXPORT_SYMBOL(security_locked_down); +/** + * security_bdev_alloc() - Allocate a block device LSM blob + * @bdev: block device + * + * Allocate and attach a security structure to @bdev->bd_security. The + * security field is initialized to NULL when the bdev structure is + * allocated. + * + * Return: Return 0 if operation was successful. + */ +int security_bdev_alloc(struct block_device *bdev) +{ + int rc = 0; + + rc = lsm_bdev_alloc(bdev); + if (unlikely(rc)) + return rc; + + rc = call_int_hook(bdev_alloc_security, bdev); + if (unlikely(rc)) + security_bdev_free(bdev); + + return rc; +} +EXPORT_SYMBOL(security_bdev_alloc); + +/** + * security_bdev_free() - Free a block device's LSM blob + * @bdev: block device + * + * Deallocate the bdev security structure and set @bdev->bd_security to NULL. + */ +void security_bdev_free(struct block_device *bdev) +{ + if (!bdev->bd_security) + return; + + call_void_hook(bdev_free_security, bdev); + + kfree(bdev->bd_security); + bdev->bd_security = NULL; +} +EXPORT_SYMBOL(security_bdev_free); + +/** + * security_bdev_setintegrity() - Set the device's integrity data + * @bdev: block device + * @type: type of integrity, e.g. hash digest, signature, etc + * @value: the integrity value + * @size: size of the integrity value + * + * Register a verified integrity measurement of a bdev with LSMs. + * LSMs should free the previously saved data if @value is NULL. + * Please note that the new hook should be invoked every time the security + * information is updated to keep these data current. For example, in dm-verity, + * if the mapping table is reloaded and configured to use a different dm-verity + * target with a new roothash and signing information, the previously stored + * data in the LSM blob will become obsolete. It is crucial to re-invoke the + * hook to refresh these data and ensure they are up to date. This necessity + * arises from the design of device-mapper, where a device-mapper device is + * first created, and then targets are subsequently loaded into it. These + * targets can be modified multiple times during the device's lifetime. + * Therefore, while the LSM blob is allocated during the creation of the block + * device, its actual contents are not initialized at this stage and can change + * substantially over time. This includes alterations from data that the LSMs + * 'trusts' to those they do not, making it essential to handle these changes + * correctly. Failure to address this dynamic aspect could potentially allow + * for bypassing LSM checks. + * + * Return: Returns 0 on success, negative values on failure. + */ +int security_bdev_setintegrity(struct block_device *bdev, + enum lsm_integrity_type type, const void *value, + size_t size) +{ + return call_int_hook(bdev_setintegrity, bdev, type, value, size); +} +EXPORT_SYMBOL(security_bdev_setintegrity); + #ifdef CONFIG_PERF_EVENTS /** * security_perf_event_open() - Check if a perf event open is allowed @@ -5621,7 +5871,19 @@ int security_perf_event_open(struct perf_event_attr *attr, int type) */ int security_perf_event_alloc(struct perf_event *event) { - return call_int_hook(perf_event_alloc, event); + int rc; + + rc = lsm_blob_alloc(&event->security, blob_sizes.lbs_perf_event, + GFP_KERNEL); + if (rc) + return rc; + + rc = call_int_hook(perf_event_alloc, event); + if (rc) { + kfree(event->security); + event->security = NULL; + } + return rc; } /** @@ -5632,7 +5894,8 @@ int security_perf_event_alloc(struct perf_event *event) */ void security_perf_event_free(struct perf_event *event) { - call_void_hook(perf_event_free, event); + kfree(event->security); + event->security = NULL; } /** @@ -5703,3 +5966,13 @@ int security_uring_cmd(struct io_uring_cmd *ioucmd) return call_int_hook(uring_cmd, ioucmd); } #endif /* CONFIG_IO_URING */ + +/** + * security_initramfs_populated() - Notify LSMs that initramfs has been loaded + * + * Tells the LSMs the initramfs has been unpacked into the rootfs. + */ +void security_initramfs_populated(void) +{ + call_void_hook(initramfs_populated); +} diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index e9b630de2f79..bd3293021488 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2207,23 +2207,16 @@ static int selinux_syslog(int type) } /* - * Check that a process has enough memory to allocate a new virtual - * mapping. 0 means there is enough memory for the allocation to - * succeed and -ENOMEM implies there is not. + * Check permission for allocating a new virtual mapping. Returns + * 0 if permission is granted, negative error code if not. * * Do not audit the selinux permission check, as this is applied to all * processes that allocate mappings. */ static int selinux_vm_enough_memory(struct mm_struct *mm, long pages) { - int rc, cap_sys_admin = 0; - - rc = cred_has_capability(current_cred(), CAP_SYS_ADMIN, - CAP_OPT_NOAUDIT, true); - if (rc == 0) - cap_sys_admin = 1; - - return cap_sys_admin; + return cred_has_capability(current_cred(), CAP_SYS_ADMIN, + CAP_OPT_NOAUDIT, true); } /* binprm security operations */ @@ -3543,8 +3536,8 @@ static int selinux_inode_copy_up_xattr(struct dentry *dentry, const char *name) * xattrs up. Instead, filter out SELinux-related xattrs following * policy load. */ - if (selinux_initialized() && strcmp(name, XATTR_NAME_SELINUX) == 0) - return 1; /* Discard */ + if (selinux_initialized() && !strcmp(name, XATTR_NAME_SELINUX)) + return -ECANCELED; /* Discard */ /* * Any other attribute apart from SELINUX is not claimed, supported * by selinux. @@ -4599,7 +4592,7 @@ static int socket_sockcreate_sid(const struct task_security_struct *tsec, static int sock_has_perm(struct sock *sk, u32 perms) { - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); struct common_audit_data ad; struct lsm_network_audit net; @@ -4667,7 +4660,7 @@ static int selinux_socket_post_create(struct socket *sock, int family, isec->initialized = LABEL_INITIALIZED; if (sock->sk) { - sksec = sock->sk->sk_security; + sksec = selinux_sock(sock->sk); sksec->sclass = sclass; sksec->sid = sid; /* Allows detection of the first association on this socket */ @@ -4683,8 +4676,8 @@ static int selinux_socket_post_create(struct socket *sock, int family, static int selinux_socket_socketpair(struct socket *socka, struct socket *sockb) { - struct sk_security_struct *sksec_a = socka->sk->sk_security; - struct sk_security_struct *sksec_b = sockb->sk->sk_security; + struct sk_security_struct *sksec_a = selinux_sock(socka->sk); + struct sk_security_struct *sksec_b = selinux_sock(sockb->sk); sksec_a->peer_sid = sksec_b->sid; sksec_b->peer_sid = sksec_a->sid; @@ -4699,7 +4692,7 @@ static int selinux_socket_socketpair(struct socket *socka, static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen) { struct sock *sk = sock->sk; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); u16 family; int err; @@ -4839,7 +4832,7 @@ static int selinux_socket_connect_helper(struct socket *sock, struct sockaddr *address, int addrlen) { struct sock *sk = sock->sk; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); int err; err = sock_has_perm(sk, SOCKET__CONNECT); @@ -5017,9 +5010,9 @@ static int selinux_socket_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk) { - struct sk_security_struct *sksec_sock = sock->sk_security; - struct sk_security_struct *sksec_other = other->sk_security; - struct sk_security_struct *sksec_new = newsk->sk_security; + struct sk_security_struct *sksec_sock = selinux_sock(sock); + struct sk_security_struct *sksec_other = selinux_sock(other); + struct sk_security_struct *sksec_new = selinux_sock(newsk); struct common_audit_data ad; struct lsm_network_audit net; int err; @@ -5048,8 +5041,8 @@ static int selinux_socket_unix_stream_connect(struct sock *sock, static int selinux_socket_unix_may_send(struct socket *sock, struct socket *other) { - struct sk_security_struct *ssec = sock->sk->sk_security; - struct sk_security_struct *osec = other->sk->sk_security; + struct sk_security_struct *ssec = selinux_sock(sock->sk); + struct sk_security_struct *osec = selinux_sock(other->sk); struct common_audit_data ad; struct lsm_network_audit net; @@ -5086,7 +5079,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb, u16 family) { int err = 0; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); u32 sk_sid = sksec->sid; struct common_audit_data ad; struct lsm_network_audit net; @@ -5115,7 +5108,7 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb, static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) { int err, peerlbl_active, secmark_active; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); u16 family = sk->sk_family; u32 sk_sid = sksec->sid; struct common_audit_data ad; @@ -5183,7 +5176,7 @@ static int selinux_socket_getpeersec_stream(struct socket *sock, int err = 0; char *scontext = NULL; u32 scontext_len; - struct sk_security_struct *sksec = sock->sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sock->sk); u32 peer_sid = SECSID_NULL; if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET || @@ -5243,34 +5236,27 @@ static int selinux_socket_getpeersec_dgram(struct socket *sock, static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority) { - struct sk_security_struct *sksec; - - sksec = kzalloc(sizeof(*sksec), priority); - if (!sksec) - return -ENOMEM; + struct sk_security_struct *sksec = selinux_sock(sk); sksec->peer_sid = SECINITSID_UNLABELED; sksec->sid = SECINITSID_UNLABELED; sksec->sclass = SECCLASS_SOCKET; selinux_netlbl_sk_security_reset(sksec); - sk->sk_security = sksec; return 0; } static void selinux_sk_free_security(struct sock *sk) { - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); - sk->sk_security = NULL; selinux_netlbl_sk_security_free(sksec); - kfree(sksec); } static void selinux_sk_clone_security(const struct sock *sk, struct sock *newsk) { - struct sk_security_struct *sksec = sk->sk_security; - struct sk_security_struct *newsksec = newsk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); + struct sk_security_struct *newsksec = selinux_sock(newsk); newsksec->sid = sksec->sid; newsksec->peer_sid = sksec->peer_sid; @@ -5284,7 +5270,7 @@ static void selinux_sk_getsecid(const struct sock *sk, u32 *secid) if (!sk) *secid = SECINITSID_ANY_SOCKET; else { - const struct sk_security_struct *sksec = sk->sk_security; + const struct sk_security_struct *sksec = selinux_sock(sk); *secid = sksec->sid; } @@ -5294,7 +5280,7 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent) { struct inode_security_struct *isec = inode_security_novalidate(SOCK_INODE(parent)); - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); if (sk->sk_family == PF_INET || sk->sk_family == PF_INET6 || sk->sk_family == PF_UNIX) @@ -5311,7 +5297,7 @@ static int selinux_sctp_process_new_assoc(struct sctp_association *asoc, { struct sock *sk = asoc->base.sk; u16 family = sk->sk_family; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); struct common_audit_data ad; struct lsm_network_audit net; int err; @@ -5366,7 +5352,7 @@ static int selinux_sctp_process_new_assoc(struct sctp_association *asoc, static int selinux_sctp_assoc_request(struct sctp_association *asoc, struct sk_buff *skb) { - struct sk_security_struct *sksec = asoc->base.sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(asoc->base.sk); u32 conn_sid; int err; @@ -5399,7 +5385,7 @@ static int selinux_sctp_assoc_request(struct sctp_association *asoc, static int selinux_sctp_assoc_established(struct sctp_association *asoc, struct sk_buff *skb) { - struct sk_security_struct *sksec = asoc->base.sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(asoc->base.sk); if (!selinux_policycap_extsockclass()) return 0; @@ -5498,8 +5484,8 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname, static void selinux_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk, struct sock *newsk) { - struct sk_security_struct *sksec = sk->sk_security; - struct sk_security_struct *newsksec = newsk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); + struct sk_security_struct *newsksec = selinux_sock(newsk); /* If policy does not support SECCLASS_SCTP_SOCKET then call * the non-sctp clone version. @@ -5515,8 +5501,8 @@ static void selinux_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk static int selinux_mptcp_add_subflow(struct sock *sk, struct sock *ssk) { - struct sk_security_struct *ssksec = ssk->sk_security; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *ssksec = selinux_sock(ssk); + struct sk_security_struct *sksec = selinux_sock(sk); ssksec->sclass = sksec->sclass; ssksec->sid = sksec->sid; @@ -5531,7 +5517,7 @@ static int selinux_mptcp_add_subflow(struct sock *sk, struct sock *ssk) static int selinux_inet_conn_request(const struct sock *sk, struct sk_buff *skb, struct request_sock *req) { - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); int err; u16 family = req->rsk_ops->family; u32 connsid; @@ -5552,7 +5538,7 @@ static int selinux_inet_conn_request(const struct sock *sk, struct sk_buff *skb, static void selinux_inet_csk_clone(struct sock *newsk, const struct request_sock *req) { - struct sk_security_struct *newsksec = newsk->sk_security; + struct sk_security_struct *newsksec = selinux_sock(newsk); newsksec->sid = req->secid; newsksec->peer_sid = req->peer_secid; @@ -5569,7 +5555,7 @@ static void selinux_inet_csk_clone(struct sock *newsk, static void selinux_inet_conn_established(struct sock *sk, struct sk_buff *skb) { u16 family = sk->sk_family; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); /* handle mapped IPv4 packets arriving via IPv6 sockets */ if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP)) @@ -5600,24 +5586,14 @@ static void selinux_req_classify_flow(const struct request_sock *req, flic->flowic_secid = req->secid; } -static int selinux_tun_dev_alloc_security(void **security) +static int selinux_tun_dev_alloc_security(void *security) { - struct tun_security_struct *tunsec; + struct tun_security_struct *tunsec = selinux_tun_dev(security); - tunsec = kzalloc(sizeof(*tunsec), GFP_KERNEL); - if (!tunsec) - return -ENOMEM; tunsec->sid = current_sid(); - - *security = tunsec; return 0; } -static void selinux_tun_dev_free_security(void *security) -{ - kfree(security); -} - static int selinux_tun_dev_create(void) { u32 sid = current_sid(); @@ -5635,7 +5611,7 @@ static int selinux_tun_dev_create(void) static int selinux_tun_dev_attach_queue(void *security) { - struct tun_security_struct *tunsec = security; + struct tun_security_struct *tunsec = selinux_tun_dev(security); return avc_has_perm(current_sid(), tunsec->sid, SECCLASS_TUN_SOCKET, TUN_SOCKET__ATTACH_QUEUE, NULL); @@ -5643,8 +5619,8 @@ static int selinux_tun_dev_attach_queue(void *security) static int selinux_tun_dev_attach(struct sock *sk, void *security) { - struct tun_security_struct *tunsec = security; - struct sk_security_struct *sksec = sk->sk_security; + struct tun_security_struct *tunsec = selinux_tun_dev(security); + struct sk_security_struct *sksec = selinux_sock(sk); /* we don't currently perform any NetLabel based labeling here and it * isn't clear that we would want to do so anyway; while we could apply @@ -5661,7 +5637,7 @@ static int selinux_tun_dev_attach(struct sock *sk, void *security) static int selinux_tun_dev_open(void *security) { - struct tun_security_struct *tunsec = security; + struct tun_security_struct *tunsec = selinux_tun_dev(security); u32 sid = current_sid(); int err; @@ -5767,7 +5743,7 @@ static unsigned int selinux_ip_output(void *priv, struct sk_buff *skb, return NF_ACCEPT; /* standard practice, label using the parent socket */ - sksec = sk->sk_security; + sksec = selinux_sock(sk); sid = sksec->sid; } else sid = SECINITSID_KERNEL; @@ -5790,7 +5766,7 @@ static unsigned int selinux_ip_postroute_compat(struct sk_buff *skb, sk = skb_to_full_sk(skb); if (sk == NULL) return NF_ACCEPT; - sksec = sk->sk_security; + sksec = selinux_sock(sk); ad_net_init_from_iif(&ad, &net, state->out->ifindex, state->pf); if (selinux_parse_skb(skb, &ad, NULL, 0, &proto)) @@ -5879,7 +5855,7 @@ static unsigned int selinux_ip_postroute(void *priv, u32 skb_sid; struct sk_security_struct *sksec; - sksec = sk->sk_security; + sksec = selinux_sock(sk); if (selinux_skb_peerlbl_sid(skb, family, &skb_sid)) return NF_DROP; /* At this point, if the returned skb peerlbl is SECSID_NULL @@ -5908,7 +5884,7 @@ static unsigned int selinux_ip_postroute(void *priv, } else { /* Locally generated packet, fetch the security label from the * associated socket. */ - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); peer_sid = sksec->sid; secmark_perm = PACKET__SEND; } @@ -5951,7 +5927,7 @@ static int selinux_netlink_send(struct sock *sk, struct sk_buff *skb) unsigned int data_len = skb->len; unsigned char *data = skb->data; struct nlmsghdr *nlh; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); u16 sclass = sksec->sclass; u32 perm; @@ -6685,11 +6661,7 @@ static int selinux_key_alloc(struct key *k, const struct cred *cred, unsigned long flags) { const struct task_security_struct *tsec; - struct key_security_struct *ksec; - - ksec = kzalloc(sizeof(struct key_security_struct), GFP_KERNEL); - if (!ksec) - return -ENOMEM; + struct key_security_struct *ksec = selinux_key(k); tsec = selinux_cred(cred); if (tsec->keycreate_sid) @@ -6697,18 +6669,9 @@ static int selinux_key_alloc(struct key *k, const struct cred *cred, else ksec->sid = tsec->sid; - k->security = ksec; return 0; } -static void selinux_key_free(struct key *k) -{ - struct key_security_struct *ksec = k->security; - - k->security = NULL; - kfree(ksec); -} - static int selinux_key_permission(key_ref_t key_ref, const struct cred *cred, enum key_need_perm need_perm) @@ -6749,14 +6712,14 @@ static int selinux_key_permission(key_ref_t key_ref, sid = cred_sid(cred); key = key_ref_to_ptr(key_ref); - ksec = key->security; + ksec = selinux_key(key); return avc_has_perm(sid, ksec->sid, SECCLASS_KEY, perm, NULL); } static int selinux_key_getsecurity(struct key *key, char **_buffer) { - struct key_security_struct *ksec = key->security; + struct key_security_struct *ksec = selinux_key(key); char *context = NULL; unsigned len; int rc; @@ -6826,23 +6789,13 @@ static int selinux_ib_endport_manage_subnet(void *ib_sec, const char *dev_name, INFINIBAND_ENDPORT__MANAGE_SUBNET, &ad); } -static int selinux_ib_alloc_security(void **ib_sec) +static int selinux_ib_alloc_security(void *ib_sec) { - struct ib_security_struct *sec; + struct ib_security_struct *sec = selinux_ib(ib_sec); - sec = kzalloc(sizeof(*sec), GFP_KERNEL); - if (!sec) - return -ENOMEM; sec->sid = current_sid(); - - *ib_sec = sec; return 0; } - -static void selinux_ib_free_security(void *ib_sec) -{ - kfree(ib_sec); -} #endif #ifdef CONFIG_BPF_SYSCALL @@ -7008,9 +6961,16 @@ struct lsm_blob_sizes selinux_blob_sizes __ro_after_init = { .lbs_file = sizeof(struct file_security_struct), .lbs_inode = sizeof(struct inode_security_struct), .lbs_ipc = sizeof(struct ipc_security_struct), + .lbs_key = sizeof(struct key_security_struct), .lbs_msg_msg = sizeof(struct msg_security_struct), +#ifdef CONFIG_PERF_EVENTS + .lbs_perf_event = sizeof(struct perf_event_security_struct), +#endif + .lbs_sock = sizeof(struct sk_security_struct), .lbs_superblock = sizeof(struct superblock_security_struct), .lbs_xattr_count = SELINUX_INODE_INIT_XATTRS, + .lbs_tun_dev = sizeof(struct tun_security_struct), + .lbs_ib = sizeof(struct ib_security_struct), }; #ifdef CONFIG_PERF_EVENTS @@ -7037,24 +6997,12 @@ static int selinux_perf_event_alloc(struct perf_event *event) { struct perf_event_security_struct *perfsec; - perfsec = kzalloc(sizeof(*perfsec), GFP_KERNEL); - if (!perfsec) - return -ENOMEM; - + perfsec = selinux_perf_event(event->security); perfsec->sid = current_sid(); - event->security = perfsec; return 0; } -static void selinux_perf_event_free(struct perf_event *event) -{ - struct perf_event_security_struct *perfsec = event->security; - - event->security = NULL; - kfree(perfsec); -} - static int selinux_perf_event_read(struct perf_event *event) { struct perf_event_security_struct *perfsec = event->security; @@ -7322,7 +7270,6 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = { LSM_HOOK_INIT(secmark_refcount_inc, selinux_secmark_refcount_inc), LSM_HOOK_INIT(secmark_refcount_dec, selinux_secmark_refcount_dec), LSM_HOOK_INIT(req_classify_flow, selinux_req_classify_flow), - LSM_HOOK_INIT(tun_dev_free_security, selinux_tun_dev_free_security), LSM_HOOK_INIT(tun_dev_create, selinux_tun_dev_create), LSM_HOOK_INIT(tun_dev_attach_queue, selinux_tun_dev_attach_queue), LSM_HOOK_INIT(tun_dev_attach, selinux_tun_dev_attach), @@ -7331,7 +7278,6 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = { LSM_HOOK_INIT(ib_pkey_access, selinux_ib_pkey_access), LSM_HOOK_INIT(ib_endport_manage_subnet, selinux_ib_endport_manage_subnet), - LSM_HOOK_INIT(ib_free_security, selinux_ib_free_security), #endif #ifdef CONFIG_SECURITY_NETWORK_XFRM LSM_HOOK_INIT(xfrm_policy_free_security, selinux_xfrm_policy_free), @@ -7345,7 +7291,6 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = { #endif #ifdef CONFIG_KEYS - LSM_HOOK_INIT(key_free, selinux_key_free), LSM_HOOK_INIT(key_permission, selinux_key_permission), LSM_HOOK_INIT(key_getsecurity, selinux_key_getsecurity), #ifdef CONFIG_KEY_NOTIFICATIONS @@ -7370,7 +7315,6 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = { #ifdef CONFIG_PERF_EVENTS LSM_HOOK_INIT(perf_event_open, selinux_perf_event_open), - LSM_HOOK_INIT(perf_event_free, selinux_perf_event_free), LSM_HOOK_INIT(perf_event_read, selinux_perf_event_read), LSM_HOOK_INIT(perf_event_write, selinux_perf_event_write), #endif diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h index dea1d6f3ed2d..c88cae81ee4c 100644 --- a/security/selinux/include/objsec.h +++ b/security/selinux/include/objsec.h @@ -195,4 +195,32 @@ selinux_superblock(const struct super_block *superblock) return superblock->s_security + selinux_blob_sizes.lbs_superblock; } +#ifdef CONFIG_KEYS +static inline struct key_security_struct *selinux_key(const struct key *key) +{ + return key->security + selinux_blob_sizes.lbs_key; +} +#endif /* CONFIG_KEYS */ + +static inline struct sk_security_struct *selinux_sock(const struct sock *sock) +{ + return sock->sk_security + selinux_blob_sizes.lbs_sock; +} + +static inline struct tun_security_struct *selinux_tun_dev(void *security) +{ + return security + selinux_blob_sizes.lbs_tun_dev; +} + +static inline struct ib_security_struct *selinux_ib(void *ib_sec) +{ + return ib_sec + selinux_blob_sizes.lbs_ib; +} + +static inline struct perf_event_security_struct * +selinux_perf_event(void *perf_event) +{ + return perf_event + selinux_blob_sizes.lbs_perf_event; +} + #endif /* _SELINUX_OBJSEC_H_ */ diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c index 5ad2fd68abbf..d51dfe892312 100644 --- a/security/selinux/netlabel.c +++ b/security/selinux/netlabel.c @@ -17,6 +17,7 @@ #include <linux/gfp.h> #include <linux/ip.h> #include <linux/ipv6.h> +#include <linux/lsm_hooks.h> #include <net/sock.h> #include <net/netlabel.h> #include <net/ip.h> @@ -68,7 +69,7 @@ static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb, static struct netlbl_lsm_secattr *selinux_netlbl_sock_genattr(struct sock *sk) { int rc; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); struct netlbl_lsm_secattr *secattr; if (sksec->nlbl_secattr != NULL) @@ -101,7 +102,7 @@ static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr( const struct sock *sk, u32 sid) { - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); struct netlbl_lsm_secattr *secattr = sksec->nlbl_secattr; if (secattr == NULL) @@ -241,7 +242,7 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb, * being labeled by it's parent socket, if it is just exit */ sk = skb_to_full_sk(skb); if (sk != NULL) { - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); if (sksec->nlbl_state != NLBL_REQSKB) return 0; @@ -278,7 +279,7 @@ int selinux_netlbl_sctp_assoc_request(struct sctp_association *asoc, { int rc; struct netlbl_lsm_secattr secattr; - struct sk_security_struct *sksec = asoc->base.sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(asoc->base.sk); struct sockaddr_in addr4; struct sockaddr_in6 addr6; @@ -357,7 +358,7 @@ inet_conn_request_return: */ void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family) { - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); if (family == PF_INET || family == PF_INET6) sksec->nlbl_state = NLBL_LABELED; @@ -375,8 +376,8 @@ void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family) */ void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk) { - struct sk_security_struct *sksec = sk->sk_security; - struct sk_security_struct *newsksec = newsk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); + struct sk_security_struct *newsksec = selinux_sock(newsk); newsksec->nlbl_state = sksec->nlbl_state; } @@ -394,7 +395,7 @@ void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk) int selinux_netlbl_socket_post_create(struct sock *sk, u16 family) { int rc; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); struct netlbl_lsm_secattr *secattr; if (family != PF_INET && family != PF_INET6) @@ -511,7 +512,7 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock, { int rc = 0; struct sock *sk = sock->sk; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); struct netlbl_lsm_secattr secattr; if (selinux_netlbl_option(level, optname) && @@ -549,7 +550,7 @@ static int selinux_netlbl_socket_connect_helper(struct sock *sk, struct sockaddr *addr) { int rc; - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); struct netlbl_lsm_secattr *secattr; /* connected sockets are allowed to disconnect when the address family @@ -587,7 +588,7 @@ static int selinux_netlbl_socket_connect_helper(struct sock *sk, int selinux_netlbl_socket_connect_locked(struct sock *sk, struct sockaddr *addr) { - struct sk_security_struct *sksec = sk->sk_security; + struct sk_security_struct *sksec = selinux_sock(sk); if (sksec->nlbl_state != NLBL_REQSKB && sksec->nlbl_state != NLBL_CONNLABELED) diff --git a/security/smack/smack.h b/security/smack/smack.h index 041688e5a77a..dbf8d7226eb5 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -355,6 +355,18 @@ static inline struct superblock_smack *smack_superblock( return superblock->s_security + smack_blob_sizes.lbs_superblock; } +static inline struct socket_smack *smack_sock(const struct sock *sock) +{ + return sock->sk_security + smack_blob_sizes.lbs_sock; +} + +#ifdef CONFIG_KEYS +static inline struct smack_known **smack_key(const struct key *key) +{ + return key->security + smack_blob_sizes.lbs_key; +} +#endif /* CONFIG_KEYS */ + /* * Is the directory transmuting? */ diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index eac7109be1db..8069f17d4404 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1606,7 +1606,7 @@ static int smack_inode_getsecurity(struct mnt_idmap *idmap, if (sock == NULL || sock->sk == NULL) return -EOPNOTSUPP; - ssp = sock->sk->sk_security; + ssp = smack_sock(sock->sk); if (strcmp(name, XATTR_SMACK_IPIN) == 0) isp = ssp->smk_in; @@ -1994,7 +1994,7 @@ static int smack_file_receive(struct file *file) if (inode->i_sb->s_magic == SOCKFS_MAGIC) { sock = SOCKET_I(inode); - ssp = sock->sk->sk_security; + ssp = smack_sock(sock->sk); tsp = smack_cred(current_cred()); /* * If the receiving process can't write to the @@ -2409,11 +2409,7 @@ static void smack_task_to_inode(struct task_struct *p, struct inode *inode) static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags) { struct smack_known *skp = smk_of_current(); - struct socket_smack *ssp; - - ssp = kzalloc(sizeof(struct socket_smack), gfp_flags); - if (ssp == NULL) - return -ENOMEM; + struct socket_smack *ssp = smack_sock(sk); /* * Sockets created by kernel threads receive web label. @@ -2427,11 +2423,10 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags) } ssp->smk_packet = NULL; - sk->sk_security = ssp; - return 0; } +#ifdef SMACK_IPV6_PORT_LABELING /** * smack_sk_free_security - Free a socket blob * @sk: the socket @@ -2440,7 +2435,6 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags) */ static void smack_sk_free_security(struct sock *sk) { -#ifdef SMACK_IPV6_PORT_LABELING struct smk_port_label *spp; if (sk->sk_family == PF_INET6) { @@ -2453,9 +2447,8 @@ static void smack_sk_free_security(struct sock *sk) } rcu_read_unlock(); } -#endif - kfree(sk->sk_security); } +#endif /** * smack_sk_clone_security - Copy security context @@ -2466,8 +2459,8 @@ static void smack_sk_free_security(struct sock *sk) */ static void smack_sk_clone_security(const struct sock *sk, struct sock *newsk) { - struct socket_smack *ssp_old = sk->sk_security; - struct socket_smack *ssp_new = newsk->sk_security; + struct socket_smack *ssp_old = smack_sock(sk); + struct socket_smack *ssp_new = smack_sock(newsk); *ssp_new = *ssp_old; } @@ -2583,7 +2576,7 @@ static struct smack_known *smack_ipv6host_label(struct sockaddr_in6 *sip) */ static int smack_netlbl_add(struct sock *sk) { - struct socket_smack *ssp = sk->sk_security; + struct socket_smack *ssp = smack_sock(sk); struct smack_known *skp = ssp->smk_out; int rc; @@ -2616,7 +2609,7 @@ static int smack_netlbl_add(struct sock *sk) */ static void smack_netlbl_delete(struct sock *sk) { - struct socket_smack *ssp = sk->sk_security; + struct socket_smack *ssp = smack_sock(sk); /* * Take the label off the socket if one is set. @@ -2648,7 +2641,7 @@ static int smk_ipv4_check(struct sock *sk, struct sockaddr_in *sap) struct smack_known *skp; int rc = 0; struct smack_known *hkp; - struct socket_smack *ssp = sk->sk_security; + struct socket_smack *ssp = smack_sock(sk); struct smk_audit_info ad; rcu_read_lock(); @@ -2721,7 +2714,7 @@ static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address) { struct sock *sk = sock->sk; struct sockaddr_in6 *addr6; - struct socket_smack *ssp = sock->sk->sk_security; + struct socket_smack *ssp = smack_sock(sock->sk); struct smk_port_label *spp; unsigned short port = 0; @@ -2809,7 +2802,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address, int act) { struct smk_port_label *spp; - struct socket_smack *ssp = sk->sk_security; + struct socket_smack *ssp = smack_sock(sk); struct smack_known *skp = NULL; unsigned short port; struct smack_known *object; @@ -2912,7 +2905,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name, if (sock == NULL || sock->sk == NULL) return -EOPNOTSUPP; - ssp = sock->sk->sk_security; + ssp = smack_sock(sock->sk); if (strcmp(name, XATTR_SMACK_IPIN) == 0) ssp->smk_in = skp; @@ -2960,7 +2953,7 @@ static int smack_socket_post_create(struct socket *sock, int family, * Sockets created by kernel threads receive web label. */ if (unlikely(current->flags & PF_KTHREAD)) { - ssp = sock->sk->sk_security; + ssp = smack_sock(sock->sk); ssp->smk_in = &smack_known_web; ssp->smk_out = &smack_known_web; } @@ -2985,8 +2978,8 @@ static int smack_socket_post_create(struct socket *sock, int family, static int smack_socket_socketpair(struct socket *socka, struct socket *sockb) { - struct socket_smack *asp = socka->sk->sk_security; - struct socket_smack *bsp = sockb->sk->sk_security; + struct socket_smack *asp = smack_sock(socka->sk); + struct socket_smack *bsp = smack_sock(sockb->sk); asp->smk_packet = bsp->smk_out; bsp->smk_packet = asp->smk_out; @@ -3049,7 +3042,7 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap, if (__is_defined(SMACK_IPV6_SECMARK_LABELING)) rsp = smack_ipv6host_label(sip); if (rsp != NULL) { - struct socket_smack *ssp = sock->sk->sk_security; + struct socket_smack *ssp = smack_sock(sock->sk); rc = smk_ipv6_check(ssp->smk_out, rsp, sip, SMK_CONNECTING); @@ -3844,9 +3837,9 @@ static int smack_unix_stream_connect(struct sock *sock, { struct smack_known *skp; struct smack_known *okp; - struct socket_smack *ssp = sock->sk_security; - struct socket_smack *osp = other->sk_security; - struct socket_smack *nsp = newsk->sk_security; + struct socket_smack *ssp = smack_sock(sock); + struct socket_smack *osp = smack_sock(other); + struct socket_smack *nsp = smack_sock(newsk); struct smk_audit_info ad; int rc = 0; #ifdef CONFIG_AUDIT @@ -3898,8 +3891,8 @@ static int smack_unix_stream_connect(struct sock *sock, */ static int smack_unix_may_send(struct socket *sock, struct socket *other) { - struct socket_smack *ssp = sock->sk->sk_security; - struct socket_smack *osp = other->sk->sk_security; + struct socket_smack *ssp = smack_sock(sock->sk); + struct socket_smack *osp = smack_sock(other->sk); struct smk_audit_info ad; int rc; @@ -3936,7 +3929,7 @@ static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg, struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name; #endif #ifdef SMACK_IPV6_SECMARK_LABELING - struct socket_smack *ssp = sock->sk->sk_security; + struct socket_smack *ssp = smack_sock(sock->sk); struct smack_known *rsp; #endif int rc = 0; @@ -4148,7 +4141,7 @@ static struct smack_known *smack_from_netlbl(const struct sock *sk, u16 family, netlbl_secattr_init(&secattr); if (sk) - ssp = sk->sk_security; + ssp = smack_sock(sk); if (netlbl_skbuff_getattr(skb, family, &secattr) == 0) { skp = smack_from_secattr(&secattr, ssp); @@ -4170,7 +4163,7 @@ static struct smack_known *smack_from_netlbl(const struct sock *sk, u16 family, */ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) { - struct socket_smack *ssp = sk->sk_security; + struct socket_smack *ssp = smack_sock(sk); struct smack_known *skp = NULL; int rc = 0; struct smk_audit_info ad; @@ -4274,7 +4267,7 @@ static int smack_socket_getpeersec_stream(struct socket *sock, u32 slen = 1; int rc = 0; - ssp = sock->sk->sk_security; + ssp = smack_sock(sock->sk); if (ssp->smk_packet != NULL) { rcp = ssp->smk_packet->smk_known; slen = strlen(rcp) + 1; @@ -4324,7 +4317,7 @@ static int smack_socket_getpeersec_dgram(struct socket *sock, switch (family) { case PF_UNIX: - ssp = sock->sk->sk_security; + ssp = smack_sock(sock->sk); s = ssp->smk_out->smk_secid; break; case PF_INET: @@ -4373,7 +4366,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent) (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)) return; - ssp = sk->sk_security; + ssp = smack_sock(sk); ssp->smk_in = skp; ssp->smk_out = skp; /* cssp->smk_packet is already set in smack_inet_csk_clone() */ @@ -4393,7 +4386,7 @@ static int smack_inet_conn_request(const struct sock *sk, struct sk_buff *skb, { u16 family = sk->sk_family; struct smack_known *skp; - struct socket_smack *ssp = sk->sk_security; + struct socket_smack *ssp = smack_sock(sk); struct sockaddr_in addr; struct iphdr *hdr; struct smack_known *hskp; @@ -4479,7 +4472,7 @@ static int smack_inet_conn_request(const struct sock *sk, struct sk_buff *skb, static void smack_inet_csk_clone(struct sock *sk, const struct request_sock *req) { - struct socket_smack *ssp = sk->sk_security; + struct socket_smack *ssp = smack_sock(sk); struct smack_known *skp; if (req->peer_secid != 0) { @@ -4511,24 +4504,14 @@ static void smack_inet_csk_clone(struct sock *sk, static int smack_key_alloc(struct key *key, const struct cred *cred, unsigned long flags) { + struct smack_known **blob = smack_key(key); struct smack_known *skp = smk_of_task(smack_cred(cred)); - key->security = skp; + *blob = skp; return 0; } /** - * smack_key_free - Clear the key security blob - * @key: the object - * - * Clear the blob pointer - */ -static void smack_key_free(struct key *key) -{ - key->security = NULL; -} - -/** * smack_key_permission - Smack access on a key * @key_ref: gets to the object * @cred: the credentials to use @@ -4541,6 +4524,8 @@ static int smack_key_permission(key_ref_t key_ref, const struct cred *cred, enum key_need_perm need_perm) { + struct smack_known **blob; + struct smack_known *skp; struct key *keyp; struct smk_audit_info ad; struct smack_known *tkp = smk_of_task(smack_cred(cred)); @@ -4578,7 +4563,9 @@ static int smack_key_permission(key_ref_t key_ref, * If the key hasn't been initialized give it access so that * it may do so. */ - if (keyp->security == NULL) + blob = smack_key(keyp); + skp = *blob; + if (skp == NULL) return 0; /* * This should not occur @@ -4594,8 +4581,8 @@ static int smack_key_permission(key_ref_t key_ref, ad.a.u.key_struct.key = keyp->serial; ad.a.u.key_struct.key_desc = keyp->description; #endif - rc = smk_access(tkp, keyp->security, request, &ad); - rc = smk_bu_note("key access", tkp, keyp->security, request, rc); + rc = smk_access(tkp, skp, request, &ad); + rc = smk_bu_note("key access", tkp, skp, request, rc); return rc; } @@ -4610,11 +4597,12 @@ static int smack_key_permission(key_ref_t key_ref, */ static int smack_key_getsecurity(struct key *key, char **_buffer) { - struct smack_known *skp = key->security; + struct smack_known **blob = smack_key(key); + struct smack_known *skp = *blob; size_t length; char *copy; - if (key->security == NULL) { + if (skp == NULL) { *_buffer = NULL; return 0; } @@ -4922,10 +4910,10 @@ static int smack_inode_copy_up(struct dentry *dentry, struct cred **new) static int smack_inode_copy_up_xattr(struct dentry *src, const char *name) { /* - * Return 1 if this is the smack access Smack attribute. + * Return -ECANCELED if this is the smack access Smack attribute. */ - if (strcmp(name, XATTR_NAME_SMACK) == 0) - return 1; + if (!strcmp(name, XATTR_NAME_SMACK)) + return -ECANCELED; return -EOPNOTSUPP; } @@ -5048,7 +5036,9 @@ struct lsm_blob_sizes smack_blob_sizes __ro_after_init = { .lbs_file = sizeof(struct smack_known *), .lbs_inode = sizeof(struct inode_smack), .lbs_ipc = sizeof(struct smack_known *), + .lbs_key = sizeof(struct smack_known *), .lbs_msg_msg = sizeof(struct smack_known *), + .lbs_sock = sizeof(struct socket_smack), .lbs_superblock = sizeof(struct superblock_smack), .lbs_xattr_count = SMACK_INODE_INIT_XATTRS, }; @@ -5173,7 +5163,9 @@ static struct security_hook_list smack_hooks[] __ro_after_init = { LSM_HOOK_INIT(socket_getpeersec_stream, smack_socket_getpeersec_stream), LSM_HOOK_INIT(socket_getpeersec_dgram, smack_socket_getpeersec_dgram), LSM_HOOK_INIT(sk_alloc_security, smack_sk_alloc_security), +#ifdef SMACK_IPV6_PORT_LABELING LSM_HOOK_INIT(sk_free_security, smack_sk_free_security), +#endif LSM_HOOK_INIT(sk_clone_security, smack_sk_clone_security), LSM_HOOK_INIT(sock_graft, smack_sock_graft), LSM_HOOK_INIT(inet_conn_request, smack_inet_conn_request), @@ -5182,7 +5174,6 @@ static struct security_hook_list smack_hooks[] __ro_after_init = { /* key management security hooks */ #ifdef CONFIG_KEYS LSM_HOOK_INIT(key_alloc, smack_key_alloc), - LSM_HOOK_INIT(key_free, smack_key_free), LSM_HOOK_INIT(key_permission, smack_key_permission), LSM_HOOK_INIT(key_getsecurity, smack_key_getsecurity), #ifdef CONFIG_KEY_NOTIFICATIONS diff --git a/security/smack/smack_netfilter.c b/security/smack/smack_netfilter.c index b945c1d3a743..bad71b7e648d 100644 --- a/security/smack/smack_netfilter.c +++ b/security/smack/smack_netfilter.c @@ -26,8 +26,8 @@ static unsigned int smack_ip_output(void *priv, struct socket_smack *ssp; struct smack_known *skp; - if (sk && sk->sk_security) { - ssp = sk->sk_security; + if (sk) { + ssp = smack_sock(sk); skp = ssp->smk_out; skb->secmark = skp->smk_secid; } diff --git a/tools/testing/selftests/lsm/lsm_list_modules_test.c b/tools/testing/selftests/lsm/lsm_list_modules_test.c index 06d24d4679a6..1cc8a977c711 100644 --- a/tools/testing/selftests/lsm/lsm_list_modules_test.c +++ b/tools/testing/selftests/lsm/lsm_list_modules_test.c @@ -128,6 +128,9 @@ TEST(correct_lsm_list_modules) case LSM_ID_EVM: name = "evm"; break; + case LSM_ID_IPE: + name = "ipe"; + break; default: name = "INVALID"; break; |