linux-cve-announce - CVE-2025-68740: ima: Handle error code returned by ima_filter_rule

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Message-ID: <2025122414-CVE-2025-68740-dcfd@gregkh>
Date: Wed, 24 Dec 2025 13:10:16 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68740: ima: Handle error code returned by ima_filter_rule_match()

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

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.

The Linux kernel CVE team has assigned CVE-2025-68740 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 2.6.30 with commit 4af4662fa4a9dc62289c580337ae2506339c4729 and fixed in 6.12.63 with commit c2238d487a640ae3511e1b6f4640ab27ce10d7f6
	Issue introduced in 2.6.30 with commit 4af4662fa4a9dc62289c580337ae2506339c4729 and fixed in 6.17.13 with commit de4431faf308d0c533cb386f5fa9af009bc86158
	Issue introduced in 2.6.30 with commit 4af4662fa4a9dc62289c580337ae2506339c4729 and fixed in 6.18.2 with commit 32952c4f4d1b2deb30dce72ba109da808a9018e1
	Issue introduced in 2.6.30 with commit 4af4662fa4a9dc62289c580337ae2506339c4729 and fixed in 6.19-rc1 with commit 738c9738e690f5cea24a3ad6fd2d9a323cf614f6

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-68740
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	security/integrity/ima/ima_policy.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/c2238d487a640ae3511e1b6f4640ab27ce10d7f6
	https://git.kernel.org/stable/c/de4431faf308d0c533cb386f5fa9af009bc86158
	https://git.kernel.org/stable/c/32952c4f4d1b2deb30dce72ba109da808a9018e1
	https://git.kernel.org/stable/c/738c9738e690f5cea24a3ad6fd2d9a323cf614f6