Subject: CVE-2024-44985: ipv6: prevent possible UAF in ip6_xmit()

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

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

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

ipv6: prevent possible UAF in ip6_xmit()

If skb_expand_head() returns NULL, skb has been freed
and the associated dst/idev could also have been freed.

We must use rcu_read_lock() to prevent a possible UAF.

The Linux kernel CVE team has assigned CVE-2024-44985 to this issue.

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

	Issue introduced in 5.15 with commit 0c9f227bee11 and fixed in 5.15.166 with commit 975f764e96f7
	Issue introduced in 5.15 with commit 0c9f227bee11 and fixed in 6.1.107 with commit 38a21c026ed2
	Issue introduced in 5.15 with commit 0c9f227bee11 and fixed in 6.6.48 with commit 124b428fe280
	Issue introduced in 5.15 with commit 0c9f227bee11 and fixed in 6.10.7 with commit fc88d6c1f289
	Issue introduced in 5.15 with commit 0c9f227bee11 and fixed in 6.11 with commit 2d5ff7e339d0

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-2024-44985
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:
	net/ipv6/ip6_output.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/975f764e96f71616b530e300c1bb2ac0ce0c2596
	https://git.kernel.org/stable/c/38a21c026ed2cc7232414cb166efc1923f34af17
	https://git.kernel.org/stable/c/124b428fe28064c809e4237b0b38e97200a8a4a8
	https://git.kernel.org/stable/c/fc88d6c1f2895a5775795d82ec581afdff7661d1
	https://git.kernel.org/stable/c/2d5ff7e339d04622d8282661df36151906d0e1c7