Subject: CVE-2024-46677: gtp: fix a potential NULL pointer dereference

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

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

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

gtp: fix a potential NULL pointer dereference

When sockfd_lookup() fails, gtp_encap_enable_socket() returns a
NULL pointer, but its callers only check for error pointers thus miss
the NULL pointer case.

Fix it by returning an error pointer with the error code carried from
sockfd_lookup().

(I found this bug during code inspection.)

The Linux kernel CVE team has assigned CVE-2024-46677 to this issue.

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

	Issue introduced in 4.12 with commit 1e3a3abd8b28 and fixed in 4.19.321 with commit 620fe9809752
	Issue introduced in 4.12 with commit 1e3a3abd8b28 and fixed in 5.4.283 with commit bdd99e5f0ad5
	Issue introduced in 4.12 with commit 1e3a3abd8b28 and fixed in 5.10.225 with commit 8bbb9e4e0e66
	Issue introduced in 4.12 with commit 1e3a3abd8b28 and fixed in 5.15.166 with commit 4643b91691e9
	Issue introduced in 4.12 with commit 1e3a3abd8b28 and fixed in 6.1.108 with commit e8b9930b0eb0
	Issue introduced in 4.12 with commit 1e3a3abd8b28 and fixed in 6.6.49 with commit 28c67f0f84f8
	Issue introduced in 4.12 with commit 1e3a3abd8b28 and fixed in 6.10.8 with commit 612edd35f2a3
	Issue introduced in 4.12 with commit 1e3a3abd8b28 and fixed in 6.11 with commit defd8b3c37b0

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-2024-46677
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/gtp.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/620fe9809752fae91b4190e897b81ed9976dfb39
	https://git.kernel.org/stable/c/bdd99e5f0ad5fa727b16f2101fe880aa2bff2f8e
	https://git.kernel.org/stable/c/8bbb9e4e0e66a39282e582d0440724055404b38c
	https://git.kernel.org/stable/c/4643b91691e969b1b9ad54bf552d7a990cfa3b87
	https://git.kernel.org/stable/c/e8b9930b0eb045d19e883c65ff9676fc89320c70
	https://git.kernel.org/stable/c/28c67f0f84f889fe9f4cbda8354132b20dc9212d
	https://git.kernel.org/stable/c/612edd35f2a3910ab1f61c1f2338889d4ba99fa2
	https://git.kernel.org/stable/c/defd8b3c37b0f9cb3e0f60f47d3d78d459d57fda