Subject: CVE-2024-41044: ppp: reject claimed-as-LCP but actually malformed packets

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

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

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

ppp: reject claimed-as-LCP but actually malformed packets

Since 'ppp_async_encode()' assumes valid LCP packets (with code
from 1 to 7 inclusive), add 'ppp_check_packet()' to ensure that
LCP packet has an actual body beyond PPP_LCP header bytes, and
reject claimed-as-LCP but actually malformed data otherwise.

The Linux kernel CVE team has assigned CVE-2024-41044 to this issue.

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

	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 4.19.318 with commit 97d1efd8be26
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 5.4.280 with commit 6e8f1c21174f
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 5.10.222 with commit 3ba12c2afd93
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 5.15.163 with commit ebc5c6304577
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 6.1.100 with commit 3134bdf7356e
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 6.6.41 with commit 099502ca4109
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 6.9.10 with commit d683e7f3fc48
	Issue introduced in 2.6.12 with commit 1da177e4c3f4 and fixed in 6.10 with commit f2aeb7306a89

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-2024-41044
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:
	drivers/net/ppp/ppp_generic.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/97d1efd8be26615ff680cdde86937d5943138f37
	https://git.kernel.org/stable/c/6e8f1c21174f9482033bbb59f13ce1a8cbe843c3
	https://git.kernel.org/stable/c/3ba12c2afd933fc1bf800f6d3f6c7ec8f602ce56
	https://git.kernel.org/stable/c/ebc5c630457783d17d0c438b0ad70b232a64a82f
	https://git.kernel.org/stable/c/3134bdf7356ed952dcecb480861d2afcc1e40492
	https://git.kernel.org/stable/c/099502ca410922b56353ccef2749bc0de669da78
	https://git.kernel.org/stable/c/d683e7f3fc48f59576af34631b4fb07fd931343e
	https://git.kernel.org/stable/c/f2aeb7306a898e1cbd03963d376f4b6656ca2b55