Subject: CVE-2021-47049: Drivers: hv: vmbus: Use after free in __vmbus_open()

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

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

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

Drivers: hv: vmbus: Use after free in __vmbus_open()

The "open_info" variable is added to the &vmbus_connection.chn_msg_list,
but the error handling frees "open_info" without removing it from the
list.  This will result in a use after free.  First remove it from the
list, and then free it.

The Linux kernel CVE team has assigned CVE-2021-47049 to this issue.

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

	Issue introduced in 4.14 with commit 6f3d791f3006 and fixed in 5.10.37 with commit d5c7b42c9f56
	Issue introduced in 4.14 with commit 6f3d791f3006 and fixed in 5.11.21 with commit f37dd5d1b5d3
	Issue introduced in 4.14 with commit 6f3d791f3006 and fixed in 5.12.4 with commit 2728f289b327
	Issue introduced in 4.14 with commit 6f3d791f3006 and fixed in 5.13 with commit 3e9bf43f7f7a
	Issue introduced in 4.13.9 with commit 6b32d45bd599

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-2021-47049
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/hv/channel.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/d5c7b42c9f56ca46b286daa537d181bd7f69214f
	https://git.kernel.org/stable/c/f37dd5d1b5d38a79a4f7b8dd7bbb705505f05560
	https://git.kernel.org/stable/c/2728f289b3270b0e273292b46c534421a33bbfd5
	https://git.kernel.org/stable/c/3e9bf43f7f7a46f21ec071cb47be92d0874c48da