Subject: CVE-2024-41034: nilfs2: fix kernel bug on rename operation of broken directory

From: Greg Kroah-Hartman <[email-masked]>

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

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

nilfs2: fix kernel bug on rename operation of broken directory

Syzbot reported that in rename directory operation on broken directory on
nilfs2, __block_write_begin_int() called to prepare block write may fail
BUG_ON check for access exceeding the folio/page size.

This is because nilfs_dotdot(), which gets parent directory reference
entry ("..") of the directory to be moved or renamed, does not check
consistency enough, and may return location exceeding folio/page size for
broken directories.

Fix this issue by checking required directory entries ("." and "..") in
the first chunk of the directory in nilfs_dotdot().

The Linux kernel CVE team has assigned CVE-2024-41034 to this issue.

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

	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 4.19.318 with commit ff9767ba2cb9
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 5.4.280 with commit 24c1c8566a9b
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 5.10.222 with commit a9a466a69b85
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 5.15.163 with commit 7000b438dda9
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 6.1.100 with commit 1a8879c0771a
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 6.6.41 with commit 60f61514374e
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 6.9.10 with commit 298cd810d7fb
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 6.10 with commit a9e1ddc09ca5

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-2024-41034
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/dir.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/ff9767ba2cb949701e45e6e4287f8af82986b703
	https://git.kernel.org/stable/c/24c1c8566a9b6be51f5347be2ea76e25fc82b11e
	https://git.kernel.org/stable/c/a9a466a69b85059b341239766a10efdd3ee68a4b
	https://git.kernel.org/stable/c/7000b438dda9d0f41a956fc9bffed92d2eb6be0d
	https://git.kernel.org/stable/c/1a8879c0771a68d70ee2e5e66eea34207e8c6231
	https://git.kernel.org/stable/c/60f61514374e4a0c3b65b08c6024dd7e26150bfd
	https://git.kernel.org/stable/c/298cd810d7fb687c90a14d8f9fd1b8719a7cb8a5
	https://git.kernel.org/stable/c/a9e1ddc09ca55746079cc479aa3eb6411f0d99d4