Subject: CVE-2024-41086: bcachefs: Fix sb_field_downgrade validation

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

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

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

bcachefs: Fix sb_field_downgrade validation

- bch2_sb_downgrade_validate() wasn't checking for a downgrade entry
  extending past the end of the superblock section

- for_each_downgrade_entry() is used in to_text() and needs to work on
  malformed input; it also was missing a check for a field extending
  past the end of the section

The Linux kernel CVE team has assigned CVE-2024-41086 to this issue.

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

	Issue introduced in 6.7 with commit 84f1638795da and fixed in 6.9.8 with commit bf920ed92ef2
	Issue introduced in 6.7 with commit 84f1638795da and fixed in 6.10 with commit 692aa7a54b2b

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-2024-41086
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/bcachefs/sb-downgrade.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/bf920ed92ef24dcd6970c88881cd4700b3acf05b
	https://git.kernel.org/stable/c/692aa7a54b2b28d59f24b3bf8250837805484b99