Subject: CVE-2022-48637: bnxt: prevent skb UAF after handing over to PTP worker

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

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

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

bnxt: prevent skb UAF after handing over to PTP worker

When reading the timestamp is required bnxt_tx_int() hands
over the ownership of the completed skb to the PTP worker.
The skb should not be used afterwards, as the worker may
run before the rest of our code and free the skb, leading
to a use-after-free.

Since dev_kfree_skb_any() accepts NULL make the loss of
ownership more obvious and set skb to NULL.

The Linux kernel CVE team has assigned CVE-2022-48637 to this issue.

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

	Issue introduced in 5.14 with commit 83bb623c968e and fixed in 5.15.71 with commit 08483e4c0c83
	Issue introduced in 5.14 with commit 83bb623c968e and fixed in 5.19.12 with commit 32afa1f23e42
	Issue introduced in 5.14 with commit 83bb623c968e and fixed in 6.0 with commit c31f26c8f69f

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-2022-48637
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/broadcom/bnxt/bnxt.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/08483e4c0c83b221b8891434a04cec405dee94a6
	https://git.kernel.org/stable/c/32afa1f23e42cc635ccf4c39f24514d03d1e8338
	https://git.kernel.org/stable/c/c31f26c8f69f776759cbbdfb38e40ea91aa0dd65