cve/published/2022/CVE-2022-49325.mbox

From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: <linux-cve-announce@vger.kernel.org>
Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org>
Subject: CVE-2022-49325: tcp: add accessors to read/set tp->snd_cwnd

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

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

tcp: add accessors to read/set tp->snd_cwnd

We had various bugs over the years with code
breaking the assumption that tp->snd_cwnd is greater
than zero.

Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added
in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction")
can trigger, and without a repro we would have to spend
considerable time finding the bug.

Instead of complaining too late, we want to catch where
and when tp->snd_cwnd is set to an illegal value.

The Linux kernel CVE team has assigned CVE-2022-49325 to this issue.


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

	Fixed in 5.15.47 with commit 3308676ec525901bf1656014003c443a60730a04
	Fixed in 5.17.15 with commit 5aba0ad44fb4a7fb78c5076c313456de199a3c29
	Fixed in 5.18.4 with commit 41e191fe72282e193a7744e2fc1786b23156c9e4
	Fixed in 5.19 with commit 40570375356c874b1578e05c1dcc3ff7c1322dbe

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-2022-49325
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/net/tcp.h
	include/trace/events/tcp.h
	net/core/filter.c
	net/ipv4/tcp.c
	net/ipv4/tcp_bbr.c
	net/ipv4/tcp_bic.c
	net/ipv4/tcp_cdg.c
	net/ipv4/tcp_cong.c
	net/ipv4/tcp_cubic.c
	net/ipv4/tcp_dctcp.c
	net/ipv4/tcp_highspeed.c
	net/ipv4/tcp_htcp.c
	net/ipv4/tcp_hybla.c
	net/ipv4/tcp_illinois.c
	net/ipv4/tcp_input.c
	net/ipv4/tcp_ipv4.c
	net/ipv4/tcp_lp.c
	net/ipv4/tcp_metrics.c
	net/ipv4/tcp_nv.c
	net/ipv4/tcp_output.c
	net/ipv4/tcp_rate.c
	net/ipv4/tcp_scalable.c
	net/ipv4/tcp_vegas.c
	net/ipv4/tcp_veno.c
	net/ipv4/tcp_westwood.c
	net/ipv4/tcp_yeah.c
	net/ipv6/tcp_ipv6.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/3308676ec525901bf1656014003c443a60730a04
	https://git.kernel.org/stable/c/5aba0ad44fb4a7fb78c5076c313456de199a3c29
	https://git.kernel.org/stable/c/41e191fe72282e193a7744e2fc1786b23156c9e4
	https://git.kernel.org/stable/c/40570375356c874b1578e05c1dcc3ff7c1322dbe