kernel/linux.git/security/selinux/include, branch v5.12.1

Merge tag 'selinux-pr-20210322' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

2021-03-22T18:34:31+00:00

Pull selinux fixes from Paul Moore: "Three SELinux patches: - Fix a problem where a local variable is used outside its associated function. Thankfully this can only be triggered by reloading the SELinux policy, which is a restricted operation for other obvious reasons. - Fix some incorrect, and inconsistent, audit and printk messages when loading the SELinux policy. All three patches are relatively minor and have been through our testing with no failures" * tag 'selinux-pr-20210322' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: selinuxfs: unify policy load error reporting selinux: fix variable scope issue in live sidtab conversion selinux: don't log MAC_POLICY_LOAD record on failed policy load

selinux: fix variable scope issue in live sidtab conversion

2021-03-19T03:23:46+00:00

Commit 02a52c5c8c3b ("selinux: move policy commit after updating selinuxfs") moved the selinux_policy_commit() call out of security_load_policy() into sel_write_load(), which caused a subtle yet rather serious bug. The problem is that security_load_policy() passes a reference to the convert_params local variable to sidtab_convert(), which stores it in the sidtab, where it may be accessed until the policy is swapped over and RCU synchronized. Before 02a52c5c8c3b, selinux_policy_commit() was called directly from security_load_policy(), so the convert_params pointer remained valid all the way until the old sidtab was destroyed, but now that's no longer the case and calls to sidtab_context_to_sid() on the old sidtab after security_load_policy() returns may cause invalid memory accesses. This can be easily triggered using the stress test from commit ee1a84fdfeed ("selinux: overhaul sidtab to fix bug and improve performance"): ``` function rand_cat() { echo $(( $RANDOM % 1024 )) } function do_work() { while true; do echo -n "system_u:system_r:kernel_t:s0:c$(rand_cat),c$(rand_cat)" \ >/sys/fs/selinux/context 2>/dev/null || true done } do_work >/dev/null & do_work >/dev/null & do_work >/dev/null & while load_policy; do echo -n .; sleep 0.1; done kill %1 kill %2 kill %3 ``` Fix this by allocating the temporary sidtab convert structures dynamically and passing them among the selinux_policy_{load,cancel,commit} functions. Fixes: 02a52c5c8c3b ("selinux: move policy commit after updating selinuxfs") Cc: stable@vger.kernel.org Tested-by: Tyler Hicks Reviewed-by: Tyler Hicks Signed-off-by: Ondrej Mosnacek [PM: merge fuzz in security.h and services.c] Signed-off-by: Paul Moore

Merge tag 'integrity-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

2021-02-22T01:08:06+00:00

Pull IMA updates from Mimi Zohar: "New is IMA support for measuring kernel critical data, as per usual based on policy. The first example measures the in memory SELinux policy. The second example measures the kernel version. In addition are four bug fixes to address memory leaks and a missing 'static' function declaration" * tag 'integrity-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: integrity: Make function integrity_add_key() static ima: Free IMA measurement buffer after kexec syscall ima: Free IMA measurement buffer on error IMA: Measure kernel version in early boot selinux: include a consumer of the new IMA critical data hook IMA: define a builtin critical data measurement policy IMA: extend critical data hook to limit the measurement based on a label IMA: limit critical data measurement based on a label IMA: add policy rule to measure critical data IMA: define a hook to measure kernel integrity critical data IMA: add support to measure buffer data hash IMA: generalize keyring specific measurement constructs evm: Fix memleak in init_desc

selinux: include a consumer of the new IMA critical data hook

2021-01-15T04:41:46+00:00

SELinux stores the active policy in memory, so the changes to this data at runtime would have an impact on the security guarantees provided by SELinux. Measuring in-memory SELinux policy through IMA subsystem provides a secure way for the attestation service to remotely validate the policy contents at runtime. Measure the hash of the loaded policy by calling the IMA hook ima_measure_critical_data(). Since the size of the loaded policy can be large (several MB), measure the hash of the policy instead of the entire policy to avoid bloating the IMA log entry. To enable SELinux data measurement, the following steps are required: 1, Add "ima_policy=critical_data" to the kernel command line arguments to enable measuring SELinux data at boot time. For example, BOOT_IMAGE=/boot/vmlinuz-5.10.0-rc1+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset security=selinux ima_policy=critical_data 2, Add the following rule to /etc/ima/ima-policy measure func=CRITICAL_DATA label=selinux Sample measurement of the hash of SELinux policy: To verify the measured data with the current SELinux policy run the following commands and verify the output hash values match. sha256sum /sys/fs/selinux/policy | cut -d' ' -f 1 grep "selinux-policy-hash" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6 Note that the actual verification of SELinux policy would require loading the expected policy into an identical kernel on a pristine/known-safe system and run the sha256sum /sys/kernel/selinux/policy there to get the expected hash. Signed-off-by: Lakshmi Ramasubramanian Suggested-by: Stephen Smalley Acked-by: Paul Moore Reviewed-by: Tyler Hicks Signed-off-by: Mimi Zohar

selinux: teach SELinux about anonymous inodes

2021-01-14T22:38:10+00:00

This change uses the anon_inodes and LSM infrastructure introduced in the previous patches to give SELinux the ability to control anonymous-inode files that are created using the new anon_inode_getfd_secure() function. A SELinux policy author detects and controls these anonymous inodes by adding a name-based type_transition rule that assigns a new security type to anonymous-inode files created in some domain. The name used for the name-based transition is the name associated with the anonymous inode for file listings --- e.g., "[userfaultfd]" or "[perf_event]". Example: type uffd_t; type_transition sysadm_t sysadm_t : anon_inode uffd_t "[userfaultfd]"; allow sysadm_t uffd_t:anon_inode { create }; (The next patch in this series is necessary for making userfaultfd support this new interface. The example above is just for exposition.) Signed-off-by: Daniel Colascione Signed-off-by: Lokesh Gidra Signed-off-by: Paul Moore

selinux: make selinuxfs_mount static

2021-01-12T15:02:26+00:00

It is not referenced outside selinuxfs.c, so remove its extern header declaration and make it static. Signed-off-by: Ondrej Mosnacek Signed-off-by: Paul Moore

lsm,selinux: pass flowi_common instead of flowi to the LSM hooks

2020-11-23T23:36:21+00:00

As pointed out by Herbert in a recent related patch, the LSM hooks do not have the necessary address family information to use the flowi struct safely. As none of the LSMs currently use any of the protocol specific flowi information, replace the flowi pointers with pointers to the address family independent flowi_common struct. Reported-by: Herbert Xu Acked-by: James Morris Signed-off-by: Paul Moore

selinux: drop super_block backpointer from superblock_security_struct

2020-11-13T00:52:21+00:00

It appears to have been needed for selinux_complete_init() in the past, but today it's useless. Signed-off-by: Ondrej Mosnacek Signed-off-by: Paul Moore

selinux: Add helper functions to get and set checkreqprot

2020-09-15T18:36:28+00:00

checkreqprot data member in selinux_state struct is accessed directly by SELinux functions to get and set. This could cause unexpected read or write access to this data member due to compiler optimizations and/or compiler's reordering of access to this field. Add helper functions to get and set checkreqprot data member in selinux_state struct. These helper functions use READ_ONCE and WRITE_ONCE macros to ensure atomic read or write of memory for this data member. Signed-off-by: Lakshmi Ramasubramanian Suggested-by: Stephen Smalley Suggested-by: Paul Moore Acked-by: Stephen Smalley Signed-off-by: Paul Moore

selinux: access policycaps with READ_ONCE/WRITE_ONCE

2020-09-11T14:08:51+00:00

Use READ_ONCE/WRITE_ONCE for all accesses to the selinux_state.policycaps booleans to prevent compiler mischief. Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore