kernel/linux.git/security/integrity/integrity.h, branch v5.0.15

integrity: Remove references to module keyring

2018-12-17T22:09:39+00:00

From what I can tell, it has never been used. Mimi: This was introduced prior to Rusty's decision to use appended signatures for kernel modules. Signed-off-by: Thiago Jung Bauermann Acked-by: Mimi Zohar Signed-off-by: James Morris

integrity: Load certs to the platform keyring

2018-12-13T03:02:54+00:00

The patch refactors integrity_load_x509(), making it a wrapper for a new function named integrity_add_key(). This patch also defines a new function named integrity_load_cert() for loading the platform keys. Signed-off-by: Nayna Jain Reviewed-by: Mimi Zohar Acked-by: Serge Hallyn Reviewed-by: James Morris Reviewed-by: Thiago Jung Bauermann Signed-off-by: Mimi Zohar

integrity: Define a trusted platform keyring

2018-12-13T03:02:28+00:00

On secure boot enabled systems, a verified kernel may need to kexec additional kernels. For example, it may be used as a bootloader needing to kexec a target kernel or it may need to kexec a crashdump kernel. In such cases, it may want to verify the signature of the next kernel image. It is further possible that the kernel image is signed with third party keys which are stored as platform or firmware keys in the 'db' variable. The kernel, however, can not directly verify these platform keys, and an administrator may therefore not want to trust them for arbitrary usage. In order to differentiate platform keys from other keys and provide the necessary separation of trust, the kernel needs an additional keyring to store platform keys. This patch creates the new keyring called ".platform" to isolate keys provided by platform from keys by kernel. These keys are used to facilitate signature verification during kexec. Since the scope of this keyring is only the platform/firmware keys, it cannot be updated from userspace. This keyring can be enabled by setting CONFIG_INTEGRITY_PLATFORM_KEYRING. Signed-off-by: Nayna Jain Reviewed-by: Mimi Zohar Acked-by: Serge Hallyn Reviewed-by: James Morris Reviewed-by: Thiago Jung Bauermann Signed-off-by: Mimi Zohar

ima: Do not audit if CONFIG_INTEGRITY_AUDIT is not set

2018-07-18T11:27:22+00:00

If Integrity is not auditing, IMA shouldn't audit, either. Signed-off-by: Stefan Berger Acked-by: Paul Moore Signed-off-by: Mimi Zohar

integrity: Add an integrity directory in securityfs

2018-05-17T12:03:07+00:00

We want to add additional evm control nodes, and it'd be preferable not to clutter up the securityfs root directory any further. Create a new integrity directory, move the ima directory into it, create an evm directory for the evm attribute and add compatibility symlinks. Signed-off-by: Matthew Garrett Signed-off-by: Mimi Zohar

integrity: Remove unused macro IMA_ACTION_RULE_FLAGS

2018-03-25T11:26:29+00:00

This macro isn't used anymore since commit 0d73a55208e9 ("ima: re-introduce own integrity cache lock"), so remove it. Signed-off-by: Thiago Jung Bauermann Acked-by: Serge Hallyn Signed-off-by: Mimi Zohar

ima: fail signature verification based on policy

2018-03-23T10:31:37+00:00

This patch addresses the fuse privileged mounted filesystems in environments which are unwilling to accept the risk of trusting the signature verification and want to always fail safe, but are for example using a pre-built kernel. This patch defines a new builtin policy named "fail_securely", which can be specified on the boot command line as an argument to "ima_policy=". Signed-off-by: Mimi Zohar Cc: Miklos Szeredi Cc: Seth Forshee Cc: Dongsu Park Cc: Alban Crequy Acked-by: Serge Hallyn Acked-by: "Eric W. Biederman"

IMA: Support using new creds in appraisal policy

2018-03-23T10:31:11+00:00

The existing BPRM_CHECK functionality in IMA validates against the credentials of the existing process, not any new credentials that the child process may transition to. Add an additional CREDS_CHECK target and refactor IMA to pass the appropriate creds structure. In ima_bprm_check(), check with both the existing process credentials and the credentials that will be committed when the new process is started. This will not change behaviour unless the system policy is extended to include CREDS_CHECK targets - BPRM_CHECK will continue to check the same credentials that it did previously. After this patch, an IMA policy rule along the lines of: measure func=CREDS_CHECK subj_type=unconfined_t will trigger if a process is executed and runs as unconfined_t, ignoring the context of the parent process. This is in contrast to: measure func=BPRM_CHECK subj_type=unconfined_t which will trigger if the process that calls exec() is already executing in unconfined_t, ignoring the context that the child process executes into. Signed-off-by: Matthew Garrett Signed-off-by: Mimi Zohar Changelog: - initialize ima_creds_status

ima: support new "hash" and "dont_hash" policy actions

2017-12-18T14:43:38+00:00

The builtin ima_appraise_tcb policy, which is specified on the boot command line, can be replaced with a custom policy, normally early in the boot process. Custom policies can be more restrictive in some ways, like requiring file signatures, but can be less restrictive in other ways, like not appraising mutable files. With a less restrictive policy in place, files in the builtin policy might not be hashed and labeled with a security.ima hash. On reboot, files which should be labeled in the ima_appraise_tcb are not labeled, possibly preventing the system from booting properly. To resolve this problem, this patch extends the existing IMA policy actions "measure", "dont_measure", "appraise", "dont_appraise", and "audit" with "hash" and "dont_hash". The new "hash" action will write the file hash as security.ima, but without requiring the file to be appraised as well. For example, the builtin ima_appraise_tcb policy includes the rule, "appraise fowner=0". Adding the "hash fowner=0" rule to a custom policy, will cause the needed file hashes to be calculated and written as security.ima xattrs. Signed-off-by: Mimi Zohar Signed-off-by: Stefan Berger

ima: re-introduce own integrity cache lock

2017-12-11T22:20:47+00:00

Before IMA appraisal was introduced, IMA was using own integrity cache lock along with i_mutex. process_measurement and ima_file_free took the iint->mutex first and then the i_mutex, while setxattr, chmod and chown took the locks in reverse order. To resolve the potential deadlock, i_mutex was moved to protect entire IMA functionality and the redundant iint->mutex was eliminated. Solution was based on the assumption that filesystem code does not take i_mutex further. But when file is opened with O_DIRECT flag, direct-io implementation takes i_mutex and produces deadlock. Furthermore, certain other filesystem operations, such as llseek, also take i_mutex. More recently some filesystems have replaced their filesystem specific lock with the global i_rwsem to read a file. As a result, when IMA attempts to calculate the file hash, reading the file attempts to take the i_rwsem again. To resolve O_DIRECT related deadlock problem, this patch re-introduces iint->mutex. But to eliminate the original chmod() related deadlock problem, this patch eliminates the requirement for chmod hooks to take the iint->mutex by introducing additional atomic iint->attr_flags to indicate calling of the hooks. The allowed locking order is to take the iint->mutex first and then the i_rwsem. Original flags were cleared in chmod(), setxattr() or removwxattr() hooks and tested when file was closed or opened again. New atomic flags are set or cleared in those hooks and tested to clear iint->flags on close or on open. Atomic flags are following: * IMA_CHANGE_ATTR - indicates that chATTR() was called (chmod, chown, chgrp) and file attributes have changed. On file open, it causes IMA to clear iint->flags to re-evaluate policy and perform IMA functions again. * IMA_CHANGE_XATTR - indicates that setxattr or removexattr was called and extended attributes have changed. On file open, it causes IMA to clear iint->flags IMA_DONE_MASK to re-appraise. * IMA_UPDATE_XATTR - indicates that security.ima needs to be updated. It is cleared if file policy changes and no update is needed. * IMA_DIGSIG - indicates that file security.ima has signature and file security.ima must not update to file has on file close. * IMA_MUST_MEASURE - indicates the file is in the measurement policy. Fixes: Commit 6552321831dc ("xfs: remove i_iolock and use i_rwsem in the VFS inode instead") Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar