Subject: CVE-2024-26632: block: Fix iterating over an empty bio with bio_for_each_folio_all

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

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

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

block: Fix iterating over an empty bio with bio_for_each_folio_all

If the bio contains no data, bio_first_folio() calls page_folio() on a
NULL pointer and oopses.  Move the test that we've reached the end of
the bio from bio_next_folio() to bio_first_folio().

[axboe: add unlikely() to error case]

The Linux kernel CVE team has assigned CVE-2024-26632 to this issue.

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

	Issue introduced in 5.17 with commit 640d1930bef4 and fixed in 6.1.75 with commit c6350b5cb78e
	Issue introduced in 5.17 with commit 640d1930bef4 and fixed in 6.6.14 with commit a6bd8182137a
	Issue introduced in 5.17 with commit 640d1930bef4 and fixed in 6.7.2 with commit ca3ede3f5893
	Issue introduced in 5.17 with commit 640d1930bef4 and fixed in 6.8 with commit 7bed6f3d08b7

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-2024-26632
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:
	include/linux/bio.h

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/c6350b5cb78e9024c49eaee6fdb914ad2903a5fe
	https://git.kernel.org/stable/c/a6bd8182137a12d22d3f2cee463271bdcb491659
	https://git.kernel.org/stable/c/ca3ede3f5893e2d26d4dbdef1eec28a8487fafde
	https://git.kernel.org/stable/c/7bed6f3d08b7af27b7015da8dc3acf2b9c1f21d7