Subject: CVE-2024-42295: nilfs2: handle inconsistent state in nilfs_btnode_create_block()

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

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

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

nilfs2: handle inconsistent state in nilfs_btnode_create_block()

Syzbot reported that a buffer state inconsistency was detected in
nilfs_btnode_create_block(), triggering a kernel bug.

It is not appropriate to treat this inconsistency as a bug; it can occur
if the argument block address (the buffer index of the newly created
block) is a virtual block number and has been reallocated due to
corruption of the bitmap used to manage its allocation state.

So, modify nilfs_btnode_create_block() and its callers to treat it as a
possible filesystem error, rather than triggering a kernel bug.

The Linux kernel CVE team has assigned CVE-2024-42295 to this issue.

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

	Issue introduced in 2.6.30 with commit a60be987d45d and fixed in 4.19.320 with commit 19cce46238ff
	Issue introduced in 2.6.30 with commit a60be987d45d and fixed in 5.4.282 with commit 02b87e6334a3
	Issue introduced in 2.6.30 with commit a60be987d45d and fixed in 5.10.224 with commit 5f0a6800b8ae
	Issue introduced in 2.6.30 with commit a60be987d45d and fixed in 5.15.165 with commit e34191cce3ee
	Issue introduced in 2.6.30 with commit a60be987d45d and fixed in 6.1.103 with commit 012be828a118
	Issue introduced in 2.6.30 with commit a60be987d45d and fixed in 6.6.44 with commit be56dfc9be06
	Issue introduced in 2.6.30 with commit a60be987d45d and fixed in 6.10.3 with commit 366c3f688dd0
	Issue introduced in 2.6.30 with commit a60be987d45d and fixed in 6.11 with commit 4811f7af6090

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-2024-42295
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/btnode.c
	fs/nilfs2/btree.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/19cce46238ffe3546e44b9c74057103ff8b24c62
	https://git.kernel.org/stable/c/02b87e6334a38c65eef49848d3f1ac422f0b2a44
	https://git.kernel.org/stable/c/5f0a6800b8aec1b453c7fe4c44fcaac5ffe9d52e
	https://git.kernel.org/stable/c/e34191cce3ee63dfa5fb241904aaf2a042d5b6d8
	https://git.kernel.org/stable/c/012be828a118bf496e666ef1fc47fc0e7358ada2
	https://git.kernel.org/stable/c/be56dfc9be0604291267c07b0e27a69a6bda4899
	https://git.kernel.org/stable/c/366c3f688dd0288cbe38af1d3a886b5c62372e4a
	https://git.kernel.org/stable/c/4811f7af6090e8f5a398fbdd766f903ef6c0d787