Message-ID: <2025091718-CVE-2023-53337-ac33@gregkh>
Date: Wed, 17 Sep 2025 16:56:36 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53337: nilfs2: do not write dirty data after degenerating to read-only

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

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

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

nilfs2: do not write dirty data after degenerating to read-only

According to syzbot's report, mark_buffer_dirty() called from
nilfs_segctor_do_construct() outputs a warning with some patterns after
nilfs2 detects metadata corruption and degrades to read-only mode.

After such read-only degeneration, page cache data may be cleared through
nilfs_clear_dirty_page() which may also clear the uptodate flag for their
buffer heads.  However, even after the degeneration, log writes are still
performed by unmount processing etc., which causes mark_buffer_dirty() to
be called for buffer heads without the "uptodate" flag and causes the
warning.

Since any writes should not be done to a read-only file system in the
first place, this fixes the warning in mark_buffer_dirty() by letting
nilfs_segctor_do_construct() abort early if in read-only mode.

This also changes the retry check of nilfs_segctor_write_out() to avoid
unnecessary log write retries if it detects -EROFS that
nilfs_segctor_do_construct() returned.

The Linux kernel CVE team has assigned CVE-2023-53337 to this issue.


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

	Fixed in 4.14.315 with commit bd89073fc7a5d03b1d06b372addbe405e5a925f4
	Fixed in 4.19.283 with commit e9c5412c5972124776c1b873533eb39e287a4dfa
	Fixed in 5.4.243 with commit 4569a292a84e340e97d178898ad1cfe1a3080a61
	Fixed in 5.10.180 with commit 7c3e662048053802f6b0db3a78e97f4e1f7edc4f
	Fixed in 5.15.111 with commit 13f73ef77baa4764dc1ca4fcbae9cade05b83866
	Fixed in 6.1.28 with commit a73201c607d8e506358d60aafddda4246bdd9350
	Fixed in 6.2.15 with commit 4005cec6847c06ee191583270b7cdd7e696543cc
	Fixed in 6.3.2 with commit 55f7810632f993cff622a0ddbc7c865892294b61
	Fixed in 6.4 with commit 28a65b49eb53e172d23567005465019658bfdb4d

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-2023-53337
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/nilfs2/segment.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/bd89073fc7a5d03b1d06b372addbe405e5a925f4
	https://git.kernel.org/stable/c/e9c5412c5972124776c1b873533eb39e287a4dfa
	https://git.kernel.org/stable/c/4569a292a84e340e97d178898ad1cfe1a3080a61
	https://git.kernel.org/stable/c/7c3e662048053802f6b0db3a78e97f4e1f7edc4f
	https://git.kernel.org/stable/c/13f73ef77baa4764dc1ca4fcbae9cade05b83866
	https://git.kernel.org/stable/c/a73201c607d8e506358d60aafddda4246bdd9350
	https://git.kernel.org/stable/c/4005cec6847c06ee191583270b7cdd7e696543cc
	https://git.kernel.org/stable/c/55f7810632f993cff622a0ddbc7c865892294b61
	https://git.kernel.org/stable/c/28a65b49eb53e172d23567005465019658bfdb4d

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