Subject: CVE-2024-35840: mptcp: use OPTION_MPTCP_MPJ_SYNACK in subflow_finish_connect()

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

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

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

mptcp: use OPTION_MPTCP_MPJ_SYNACK in subflow_finish_connect()

subflow_finish_connect() uses four fields (backup, join_id, thmac, none)
that may contain garbage unless OPTION_MPTCP_MPJ_SYNACK has been set
in mptcp_parse_option()

The Linux kernel CVE team has assigned CVE-2024-35840 to this issue.

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

	Issue introduced in 5.7 with commit f296234c98a8 and fixed in 5.15.148 with commit 413b91350732
	Issue introduced in 5.7 with commit f296234c98a8 and fixed in 6.1.75 with commit 51e4cb032d49
	Issue introduced in 5.7 with commit f296234c98a8 and fixed in 6.6.14 with commit ad3e8f5c3d5c
	Issue introduced in 5.7 with commit f296234c98a8 and fixed in 6.7.2 with commit 76e8de7273a2
	Issue introduced in 5.7 with commit f296234c98a8 and fixed in 6.8 with commit be1d9d9d38da

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-2024-35840
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/mptcp/subflow.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/413b913507326972135d2977975dbff8b7f2c453
	https://git.kernel.org/stable/c/51e4cb032d49ce094605f27e45eabebc0408893c
	https://git.kernel.org/stable/c/ad3e8f5c3d5c53841046ef7a947c04ad45a20721
	https://git.kernel.org/stable/c/76e8de7273a22a00d27e9b8b7d4d043d6433416a
	https://git.kernel.org/stable/c/be1d9d9d38da922bd4beeec5b6dd821ff5a1dfeb