Subject: CVE-2023-52628: netfilter: nftables: exthdr: fix 4-byte stack OOB write

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

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

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

netfilter: nftables: exthdr: fix 4-byte stack OOB write

If priv->len is a multiple of 4, then dst[len / 4] can write past
the destination array which leads to stack corruption.

This construct is necessary to clean the remainder of the register
in case ->len is NOT a multiple of the register size, so make it
conditional just like nft_payload.c does.

The bug was added in 4.1 cycle and then copied/inherited when
tcp/sctp and ip option support was added.

Bug reported by Zero Day Initiative project (ZDI-CAN-21950,
ZDI-CAN-21951, ZDI-CAN-21961).

The Linux kernel CVE team has assigned CVE-2023-52628 to this issue.

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

	Issue introduced in 4.1 with commit 49499c3e6e18 and fixed in 4.19.316 with commit 28a97c43c9e3
	Issue introduced in 4.1 with commit 49499c3e6e18 and fixed in 5.4.279 with commit cf39c4f77a77
	Issue introduced in 4.1 with commit 49499c3e6e18 and fixed in 5.10.198 with commit a7d86a77c33b
	Issue introduced in 4.1 with commit 49499c3e6e18 and fixed in 5.15.132 with commit 1ad7b189cc14
	Issue introduced in 4.1 with commit 49499c3e6e18 and fixed in 6.1.54 with commit d9ebfc0f2137
	Issue introduced in 4.1 with commit 49499c3e6e18 and fixed in 6.5.4 with commit c8f292322ff1
	Issue introduced in 4.1 with commit 49499c3e6e18 and fixed in 6.6 with commit fd94d9dadee5

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-2023-52628
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/netfilter/nft_exthdr.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/28a97c43c9e32f437ebb8d6126f9bb7f3ca9521a
	https://git.kernel.org/stable/c/cf39c4f77a773a547ac2bcf30ecdd303bb0c80cb
	https://git.kernel.org/stable/c/a7d86a77c33ba1c357a7504341172cc1507f0698
	https://git.kernel.org/stable/c/1ad7b189cc1411048434e8595ffcbe7873b71082
	https://git.kernel.org/stable/c/d9ebfc0f21377690837ebbd119e679243e0099cc
	https://git.kernel.org/stable/c/c8f292322ff16b9a2272a67de396c09a50e09dce
	https://git.kernel.org/stable/c/fd94d9dadee58e09b49075240fe83423eb1dcd36