Subject: CVE-2024-49948: net: add more sanity checks to qdisc_pkt_len_init()

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

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

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

net: add more sanity checks to qdisc_pkt_len_init()

One path takes care of SKB_GSO_DODGY, assuming
skb->len is bigger than hdr_len.

virtio_net_hdr_to_skb() does not fully dissect TCP headers,
it only make sure it is at least 20 bytes.

It is possible for an user to provide a malicious 'GSO' packet,
total length of 80 bytes.

- 20 bytes of IPv4 header
- 60 bytes TCP header
- a small gso_size like 8

virtio_net_hdr_to_skb() would declare this packet as a normal
GSO packet, because it would see 40 bytes of payload,
bigger than gso_size.

We need to make detect this case to not underflow
qdisc_skb_cb(skb)->pkt_len.

The Linux kernel CVE team has assigned CVE-2024-49948 to this issue.

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

	Issue introduced in 3.9 with commit 1def9238d4aa and fixed in 5.10.227 with commit 566a931a1436
	Issue introduced in 3.9 with commit 1def9238d4aa and fixed in 5.15.168 with commit 2415f465730e
	Issue introduced in 3.9 with commit 1def9238d4aa and fixed in 6.1.113 with commit 27a8fabc54d2
	Issue introduced in 3.9 with commit 1def9238d4aa and fixed in 6.6.55 with commit 9b0ee571d20a
	Issue introduced in 3.9 with commit 1def9238d4aa and fixed in 6.10.14 with commit ff1c3cadcf40
	Issue introduced in 3.9 with commit 1def9238d4aa and fixed in 6.11.3 with commit 1eebe602a8d8
	Issue introduced in 3.9 with commit 1def9238d4aa and fixed in 6.12-rc2 with commit ab9a9a9e9647

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-2024-49948
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/core/dev.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/566a931a1436d0e0ad13708ea55479b95426213c
	https://git.kernel.org/stable/c/2415f465730e48b6e38da1c7c097317bf5dd2d20
	https://git.kernel.org/stable/c/27a8fabc54d2f960d47bdfbebf2bdc6e8a92a4c4
	https://git.kernel.org/stable/c/9b0ee571d20a238a22722126abdfde61f1b2bdd0
	https://git.kernel.org/stable/c/ff1c3cadcf405ab37dd91418a62a7acecf3bc5e2
	https://git.kernel.org/stable/c/1eebe602a8d8264a12e35e39d0645fa88dbbacdd
	https://git.kernel.org/stable/c/ab9a9a9e9647392a19e7a885b08000e89c86b535