CVE-2022-49575: tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts.

CVE-2022-49575: tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts.

[Greg Kroah-Hartman]

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

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

tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts.

While reading sysctl_tcp_thin_linear_timeouts, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its reader.

The Linux kernel CVE team has assigned CVE-2022-49575 to this issue.


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

	Issue introduced in 2.6.34 with commit 36e31b0af58728071e8023cf8e20c5166b700717 and fixed in 4.19.254 with commit f4b0295be9a3c4260de4585fac4062e602a88ac7
	Issue introduced in 2.6.34 with commit 36e31b0af58728071e8023cf8e20c5166b700717 and fixed in 5.4.208 with commit 492f3713b282c0e67e951cd804edd22eccc25412
	Issue introduced in 2.6.34 with commit 36e31b0af58728071e8023cf8e20c5166b700717 and fixed in 5.10.134 with commit cc133e4f4bc225079198192623945bb872c08143
	Issue introduced in 2.6.34 with commit 36e31b0af58728071e8023cf8e20c5166b700717 and fixed in 5.15.58 with commit 404c53ccdebd11f96954f4070cffac8e0b4d5cb6
	Issue introduced in 2.6.34 with commit 36e31b0af58728071e8023cf8e20c5166b700717 and fixed in 5.18.15 with commit a0f96c4f179cb3560078cefccef105e8f1701210
	Issue introduced in 2.6.34 with commit 36e31b0af58728071e8023cf8e20c5166b700717 and fixed in 5.19 with commit 7c6f2a86ca590d5187a073d987e9599985fb1c7c

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-2022-49575
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/ipv4/tcp_timer.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/f4b0295be9a3c4260de4585fac4062e602a88ac7
	https://git.kernel.org/stable/c/492f3713b282c0e67e951cd804edd22eccc25412
	https://git.kernel.org/stable/c/cc133e4f4bc225079198192623945bb872c08143
	https://git.kernel.org/stable/c/404c53ccdebd11f96954f4070cffac8e0b4d5cb6
	https://git.kernel.org/stable/c/a0f96c4f179cb3560078cefccef105e8f1701210
	https://git.kernel.org/stable/c/7c6f2a86ca590d5187a073d987e9599985fb1c7c