CVE-2022-49594: tcp: Fix a data-race around sysctl_tcp_mtu_probe_floor.

CVE-2022-49594: tcp: Fix a data-race around sysctl_tcp_mtu_probe_floor.

[Greg Kroah-Hartman]

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

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

tcp: Fix a data-race around sysctl_tcp_mtu_probe_floor.

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

The Linux kernel CVE team has assigned CVE-2022-49594 to this issue.


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

	Issue introduced in 5.4 with commit c04b79b6cfd714144f6a2cf359603d82ee631e62 and fixed in 5.4.208 with commit 033963b220633ed1602d458e7e4ac06afa9fefb2
	Issue introduced in 5.4 with commit c04b79b6cfd714144f6a2cf359603d82ee631e62 and fixed in 5.10.134 with commit d5bece4df6090395f891110ef52a6f82d16685db
	Issue introduced in 5.4 with commit c04b79b6cfd714144f6a2cf359603d82ee631e62 and fixed in 5.15.58 with commit cc36c37f5fe066c4708e623ead96dc8f57224bf5
	Issue introduced in 5.4 with commit c04b79b6cfd714144f6a2cf359603d82ee631e62 and fixed in 5.18.15 with commit e2ecbf3f0aa88277d43908c53b99399d55729ff9
	Issue introduced in 5.4 with commit c04b79b6cfd714144f6a2cf359603d82ee631e62 and fixed in 5.19 with commit 8e92d4423615a5257d0d871fc067aa561f597deb

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-2022-49594
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/033963b220633ed1602d458e7e4ac06afa9fefb2
	https://git.kernel.org/stable/c/d5bece4df6090395f891110ef52a6f82d16685db
	https://git.kernel.org/stable/c/cc36c37f5fe066c4708e623ead96dc8f57224bf5
	https://git.kernel.org/stable/c/e2ecbf3f0aa88277d43908c53b99399d55729ff9
	https://git.kernel.org/stable/c/8e92d4423615a5257d0d871fc067aa561f597deb