Subject: CVE-2021-47605: vduse: fix memory corruption in vduse_dev_ioctl()

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

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

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

vduse: fix memory corruption in vduse_dev_ioctl()

The "config.offset" comes from the user.  There needs to a check to
prevent it being out of bounds.  The "config.offset" and
"dev->config_size" variables are both type u32.  So if the offset if
out of bounds then the "dev->config_size - config.offset" subtraction
results in a very high u32 value.  The out of bounds offset can result
in memory corruption.

The Linux kernel CVE team has assigned CVE-2021-47605 to this issue.

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

	Issue introduced in 5.15 with commit c8a6153b6c59 and fixed in 5.15.11 with commit e6c67560b434
	Issue introduced in 5.15 with commit c8a6153b6c59 and fixed in 5.16 with commit ff9f9c6e7484

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-2021-47605
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/vdpa/vdpa_user/vduse_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/e6c67560b4341914bec32ec536e931c22062af65
	https://git.kernel.org/stable/c/ff9f9c6e74848170fcb45c8403c80d661484c8c9