Subject: CVE-2024-38586: r8169: Fix possible ring buffer corruption on fragmented Tx packets.

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

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

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

r8169: Fix possible ring buffer corruption on fragmented Tx packets.

An issue was found on the RTL8125b when transmitting small fragmented
packets, whereby invalid entries were inserted into the transmit ring
buffer, subsequently leading to calls to dma_unmap_single() with a null
address.

This was caused by rtl8169_start_xmit() not noticing changes to nr_frags
which may occur when small packets are padded (to work around hardware
quirks) in rtl8169_tso_csum_v2().

To fix this, postpone inspecting nr_frags until after any padding has been
applied.

The Linux kernel CVE team has assigned CVE-2024-38586 to this issue.

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

	Issue introduced in 5.7 with commit 9020845fb5d6 and fixed in 5.10.221 with commit 61c1c98e2607
	Issue introduced in 5.7 with commit 9020845fb5d6 and fixed in 5.15.161 with commit b6d21cf40de1
	Issue introduced in 5.7 with commit 9020845fb5d6 and fixed in 6.1.93 with commit 0c48185a9530
	Issue introduced in 5.7 with commit 9020845fb5d6 and fixed in 6.6.33 with commit 68222d7b4b72
	Issue introduced in 5.7 with commit 9020845fb5d6 and fixed in 6.8.12 with commit 078d5b7500d7
	Issue introduced in 5.7 with commit 9020845fb5d6 and fixed in 6.9.3 with commit 54e7a0d11124
	Issue introduced in 5.7 with commit 9020845fb5d6 and fixed in 6.10 with commit c71e3a5cffd5

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-2024-38586
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/ethernet/realtek/r8169_main.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/61c1c98e2607120ce9c3fa1bf75e6da909712b27
	https://git.kernel.org/stable/c/b6d21cf40de103d63ae78551098a7c06af8c98dd
	https://git.kernel.org/stable/c/0c48185a95309556725f818b82120bb74e9c627d
	https://git.kernel.org/stable/c/68222d7b4b72aa321135cd453dac37f00ec41fd1
	https://git.kernel.org/stable/c/078d5b7500d70af2de6b38e226b03f0b932026a6
	https://git.kernel.org/stable/c/54e7a0d111240c92c0f02ceba6eb8f26bf6d6479
	https://git.kernel.org/stable/c/c71e3a5cffd5309d7f84444df03d5b72600cc417