Subject: CVE-2024-39469: nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors

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

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

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

nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors

The error handling in nilfs_empty_dir() when a directory folio/page read
fails is incorrect, as in the old ext2 implementation, and if the
folio/page cannot be read or nilfs_check_folio() fails, it will falsely
determine the directory as empty and corrupt the file system.

In addition, since nilfs_empty_dir() does not immediately return on a
failed folio/page read, but continues to loop, this can cause a long loop
with I/O if i_size of the directory's inode is also corrupted, causing the
log writer thread to wait and hang, as reported by syzbot.

Fix these issues by making nilfs_empty_dir() immediately return a false
value (0) if it fails to get a directory folio/page.

The Linux kernel CVE team has assigned CVE-2024-39469 to this issue.

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

	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 4.19.317 with commit 2ac8a2fe22bd
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 5.4.279 with commit 405b71f1251e
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 5.10.221 with commit c77ad608df6c
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 5.15.162 with commit 11a2edb70356
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 6.1.95 with commit 129dcd3e7d03
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 6.6.35 with commit d18b05eda7fa
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 6.9.5 with commit 59f14875a96e
	Issue introduced in 2.6.30 with commit 2ba466d74ed7 and fixed in 6.10 with commit 7373a51e7998

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-2024-39469
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/2ac8a2fe22bdde9eecce2a42cf5cab79333fb428
	https://git.kernel.org/stable/c/405b71f1251e5ae865f53bd27c45114e6c83bee3
	https://git.kernel.org/stable/c/c77ad608df6c091fe64ecb91f41ef7cb465587f1
	https://git.kernel.org/stable/c/11a2edb70356a2202dcb7c9c189c8356ab4752cd
	https://git.kernel.org/stable/c/129dcd3e7d036218db3f59c82d82004b9539ed82
	https://git.kernel.org/stable/c/d18b05eda7fa77f02114f15b02c009f28ee42346
	https://git.kernel.org/stable/c/59f14875a96ef93f05b82ad3c980605f2cb444b5
	https://git.kernel.org/stable/c/7373a51e7998b508af7136530f3a997b286ce81c