linux-cve-announce - CVE-2023-53224: ext4: Fix function prototype mismatch for ext4_feat

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Message-ID: <2025091513-CVE-2023-53224-190d@gregkh>
Date: Mon, 15 Sep 2025 16:21:58 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53224: ext4: Fix function prototype mismatch for ext4_feat_ktype

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

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

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

ext4: Fix function prototype mismatch for ext4_feat_ktype

With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
indirect call targets are validated against the expected function
pointer prototype to make sure the call target is valid to help mitigate
ROP attacks. If they are not identical, there is a failure at run time,
which manifests as either a kernel panic or thread getting killed.

ext4_feat_ktype was setting the "release" handler to "kfree", which
doesn't have a matching function prototype. Add a simple wrapper
with the correct prototype.

This was found as a result of Clang's new -Wcast-function-type-strict
flag, which is more sensitive than the simpler -Wcast-function-type,
which only checks for type width mismatches.

Note that this code is only reached when ext4 is a loadable module and
it is being unloaded:

 CFI failure at kobject_put+0xbb/0x1b0 (target: kfree+0x0/0x180; expected type: 0x7c4aa698)
 ...
 RIP: 0010:kobject_put+0xbb/0x1b0
 ...
 Call Trace:
  <TASK>
  ext4_exit_sysfs+0x14/0x60 [ext4]
  cleanup_module+0x67/0xedb [ext4]

The Linux kernel CVE team has assigned CVE-2023-53224 to this issue.


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

	Issue introduced in 4.16 with commit b99fee58a20ab8e0557cce87b6f187e325993142 and fixed in 4.19.274 with commit 2b69cdd9f9a7f596e3dd31f05f9852940d177924
	Issue introduced in 4.16 with commit b99fee58a20ab8e0557cce87b6f187e325993142 and fixed in 5.4.233 with commit 99e3fd21f8fc975c95e8cf76fbf6a3d2656f8f71
	Issue introduced in 4.16 with commit b99fee58a20ab8e0557cce87b6f187e325993142 and fixed in 5.10.170 with commit 1ba10d3640e9783dad811fe4e24d55465c37c64d
	Issue introduced in 4.16 with commit b99fee58a20ab8e0557cce87b6f187e325993142 and fixed in 5.15.96 with commit c98077f7598a562f51051eec043be0cb3e1b1b5e
	Issue introduced in 4.16 with commit b99fee58a20ab8e0557cce87b6f187e325993142 and fixed in 6.1.14 with commit 0a1394e07c5d6bf1bfc25db8589ff1b1bfb6f46a
	Issue introduced in 4.16 with commit b99fee58a20ab8e0557cce87b6f187e325993142 and fixed in 6.2.1 with commit 94d8de83286fb1827340eba35b61c308f6b46ead
	Issue introduced in 4.16 with commit b99fee58a20ab8e0557cce87b6f187e325993142 and fixed in 6.3 with commit 118901ad1f25d2334255b3d50512fa20591531cd

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-2023-53224
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:
	fs/ext4/sysfs.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/2b69cdd9f9a7f596e3dd31f05f9852940d177924
	https://git.kernel.org/stable/c/99e3fd21f8fc975c95e8cf76fbf6a3d2656f8f71
	https://git.kernel.org/stable/c/1ba10d3640e9783dad811fe4e24d55465c37c64d
	https://git.kernel.org/stable/c/c98077f7598a562f51051eec043be0cb3e1b1b5e
	https://git.kernel.org/stable/c/0a1394e07c5d6bf1bfc25db8589ff1b1bfb6f46a
	https://git.kernel.org/stable/c/94d8de83286fb1827340eba35b61c308f6b46ead
	https://git.kernel.org/stable/c/118901ad1f25d2334255b3d50512fa20591531cd