linux-cve-announce - CVE-2025-38651: landlock: Fix warning from KUnit tests

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Message-ID: <2025082237-CVE-2025-38651-6940@gregkh>
Date: Fri, 22 Aug 2025 18:00:59 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38651: landlock: Fix warning from KUnit tests

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

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

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

landlock: Fix warning from KUnit tests

get_id_range() expects a positive value as first argument but
get_random_u8() can return 0.  Fix this by clamping it.

Validated by running the test in a for loop for 1000 times.

Note that MAX() is wrong as it is only supposed to be used for
constants, but max() is good here.

  [..]     ok 9 test_range2_rand1
  [..]     ok 10 test_range2_rand2
  [..]     ok 11 test_range2_rand15
  [..] ------------[ cut here ]------------
  [..] WARNING: CPU: 6 PID: 104 at security/landlock/id.c:99 test_range2_rand16 (security/landlock/id.c:99 (discriminator 1) security/landlock/id.c:234 (discriminator 1))
  [..] Modules linked in:
  [..] CPU: 6 UID: 0 PID: 104 Comm: kunit_try_catch Tainted: G                 N  6.16.0-rc1-dev-00001-g314a2f98b65f #1 PREEMPT(undef)
  [..] Tainted: [N]=TEST
  [..] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
  [..] RIP: 0010:test_range2_rand16 (security/landlock/id.c:99 (discriminator 1) security/landlock/id.c:234 (discriminator 1))
  [..] Code: 49 c7 c0 10 70 30 82 4c 89 ff 48 c7 c6 a0 63 1e 83 49 c7 45 a0 e0 63 1e 83 e8 3f 95 17 00 e9 1f ff ff ff 0f 0b e9 df fd ff ff <0f> 0b ba 01 00 00 00 e9 68 fe ff ff 49 89 45 a8 49 8d 4d a0 45 31

  [..] RSP: 0000:ffff888104eb7c78 EFLAGS: 00010246
  [..] RAX: 0000000000000000 RBX: 000000000870822c RCX: 0000000000000000
            ^^^^^^^^^^^^^^^^
  [..]
  [..] Call Trace:
  [..]
  [..] ---[ end trace 0000000000000000 ]---
  [..]     ok 12 test_range2_rand16
  [..] # landlock_id: pass:12 fail:0 skip:0 total:12
  [..] # Totals: pass:12 fail:0 skip:0 total:12
  [..] ok 1 landlock_id

[mic: Minor cosmetic improvements]

The Linux kernel CVE team has assigned CVE-2025-38651 to this issue.


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

	Issue introduced in 6.15 with commit d9d2a68ed44bbae598a81cb95e0746fa6b13b57f and fixed in 6.15.10 with commit 127183361b69dbb7ac3246ad4726f93400481249
	Issue introduced in 6.15 with commit d9d2a68ed44bbae598a81cb95e0746fa6b13b57f and fixed in 6.16.1 with commit 7d9ec2cfe12dd0d7c1a58213b9bef1bec66a3189
	Issue introduced in 6.15 with commit d9d2a68ed44bbae598a81cb95e0746fa6b13b57f and fixed in 6.17-rc1 with commit e0a69cf2c03e61bd8069becb97f66c173d0d1fa1

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-2025-38651
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/landlock/id.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/127183361b69dbb7ac3246ad4726f93400481249
	https://git.kernel.org/stable/c/7d9ec2cfe12dd0d7c1a58213b9bef1bec66a3189
	https://git.kernel.org/stable/c/e0a69cf2c03e61bd8069becb97f66c173d0d1fa1