CVE-2025-68740

In the Linux kernel, the following vulnerability has been resolved:

ima: Handle error code returned by ima_filter_rule_match()

In ima_match_rules(), if ima_filter_rule_match() returns -ENOENT due to the rule being NULL, the function incorrectly skips the if (!rc) check and sets result = true. The LSM rule is considered a match, causing extra files to be measured by IMA.

This issue can be reproduced in the following scenario: After unloading the SELinux policy module via semodule -d, if an IMA measurement is triggered before ima_lsm_rules is updated, in ima_match_rules(), the first call to ima_filter_rule_match() returns -ESTALE. This causes the code to enter the if (rc == -ESTALE && !rule_reinitialized) block, perform ima_lsm_copy_rule() and retry. In ima_lsm_copy_rule(), since the SELinux module has been removed, the rule becomes NULL, and the second call to ima_filter_rule_match() returns -ENOENT. This bypasses the if (!rc) check and results in a false match.

Call trace: selinux_audit_rule_match+0x310/0x3b8 security_audit_rule_match+0x60/0xa0 ima_match_rules+0x2e4/0x4a0 ima_match_policy+0x9c/0x1e8 ima_get_action+0x48/0x60 process_measurement+0xf8/0xa98 ima_bprm_check+0x98/0xd8 security_bprm_check+0x5c/0x78 search_binary_handler+0x6c/0x318 exec_binprm+0x58/0x1b8 bprm_execve+0xb8/0x130 do_execveat_common.isra.0+0x1a8/0x258 __arm64_sys_execve+0x48/0x68 invoke_syscall+0x50/0x128 el0_svc_common.constprop.0+0xc8/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x44/0x200 el0t_64_sync_handler+0x100/0x130 el0t_64_sync+0x3c8/0x3d0

Fix this by changing if (!rc) to if (rc <= 0) to ensure that error codes like -ENOENT do not bypass the check and accidentally result in a successful match.

Affected Software

References

• https://git.kernel.org/stable/c/32952c4f4d1b2deb30dce72ba109da808a9018e1
• https://git.kernel.org/stable/c/738c9738e690f5cea24a3ad6fd2d9a323cf614f6
• https://git.kernel.org/stable/c/c2238d487a640ae3511e1b6f4640ab27ce10d7f6
• https://git.kernel.org/stable/c/de4431faf308d0c533cb386f5fa9af009bc86158