linux-cve-announce - CVE-2022-49747: erofs/zmap.c: Fix incorrect offset calculation

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Message-ID: <2025032759-CVE-2022-49747-f361@gregkh>
Date: Thu, 27 Mar 2025 17:43:05 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49747: erofs/zmap.c: Fix incorrect offset calculation

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

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

erofs/zmap.c: Fix incorrect offset calculation

Effective offset to add to length was being incorrectly calculated,
which resulted in iomap->length being set to 0, triggering a WARN_ON
in iomap_iter_done().

Fix that, and describe it in comments.

This was reported as a crash by syzbot under an issue about a warning
encountered in iomap_iter_done(), but unrelated to erofs.

C reproducer: https://syzkaller.appspot.com/text?tag=ReproC&x=1037a6b2880000
Kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=e2021a61197ebe02
Dashboard link: https://syzkaller.appspot.com/bug?extid=a8e049cd3abd342936b6

The Linux kernel CVE team has assigned CVE-2022-49747 to this issue.


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

	Fixed in 5.15.92 with commit 2144859229c1e74f52d3ea067338d314a83a8afb
	Fixed in 6.1.10 with commit 9f31d8c889d9a4e47bfcc6c4537d0c9f89fe582c
	Fixed in 6.2 with commit 6acd87d50998ef0afafc441613aeaf5a8f5c9eff

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-2022-49747
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/erofs/zmap.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/2144859229c1e74f52d3ea067338d314a83a8afb
	https://git.kernel.org/stable/c/9f31d8c889d9a4e47bfcc6c4537d0c9f89fe582c
	https://git.kernel.org/stable/c/6acd87d50998ef0afafc441613aeaf5a8f5c9eff