linux-cve-announce - CVE-2022-50329: block, bfq: fix uaf for bfqq in bfq_exit_icq

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Message-ID: <2025091554-CVE-2022-50329-58ac@gregkh>
Date: Mon, 15 Sep 2025 16:49:06 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50329: block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq

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

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

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

block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq

Commit 64dc8c732f5c ("block, bfq: fix possible uaf for 'bfqq->bic'")
will access 'bic->bfqq' in bic_set_bfqq(), however, bfq_exit_icq_bfqq()
can free bfqq first, and then call bic_set_bfqq(), which will cause uaf.

Fix the problem by moving bfq_exit_bfqq() behind bic_set_bfqq().

The Linux kernel CVE team has assigned CVE-2022-50329 to this issue.


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

	Issue introduced in 5.15.86 with commit 094f3d9314d67691cb21ba091c1b528f6e3c4893 and fixed in 5.15.87 with commit 7949b0df3dd9f4817ed4a4e989fa9ee81df6205f
	Issue introduced in 6.0.16 with commit b22fd72bfebda3956efc4431b60ddfc0a51e03e0 and fixed in 6.0.17 with commit cfe5b38c37720313eff0dec5517442c7ab3c9a20
	Issue introduced in 6.1.2 with commit 761564d93c8265f65543acf0a576b32d66bfa26a and fixed in 6.1.3 with commit 1ed959fef5b1c6f1a7a3fbea543698c30ebd6678

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-2022-50329
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:
	block/bfq-iosched.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/1425f1bb5df5239021fd09ebc2a5e8070e705d36
	https://git.kernel.org/stable/c/7949b0df3dd9f4817ed4a4e989fa9ee81df6205f
	https://git.kernel.org/stable/c/cfe5b38c37720313eff0dec5517442c7ab3c9a20
	https://git.kernel.org/stable/c/1ed959fef5b1c6f1a7a3fbea543698c30ebd6678
	https://git.kernel.org/stable/c/246cf66e300b76099b5dbd3fdd39e9a5dbc53f02