Subject: CVE-2021-47064: mt76: fix potential DMA mapping leak

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

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

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

mt76: fix potential DMA mapping leak

With buf uninitialized in mt76_dma_tx_queue_skb_raw, its field skip_unmap
could potentially inherit a non-zero value from stack garbage.
If this happens, it will cause DMA mappings for MCU command frames to not be
unmapped after completion

The Linux kernel CVE team has assigned CVE-2021-47064 to this issue.

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

	Issue introduced in 5.10 with commit 27d5c528a7ca and fixed in 5.10.37 with commit 9fa26701cd1f
	Issue introduced in 5.10 with commit 27d5c528a7ca and fixed in 5.11.21 with commit 9b68ce2856da
	Issue introduced in 5.10 with commit 27d5c528a7ca and fixed in 5.12.4 with commit 91b9548d413f
	Issue introduced in 5.10 with commit 27d5c528a7ca and fixed in 5.13 with commit b4403cee6400

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-2021-47064
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/wireless/mediatek/mt76/dma.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/9fa26701cd1fc4d932d431971efc5746325bdfce
	https://git.kernel.org/stable/c/9b68ce2856dadc0e1cb6fd21fbeb850da49efd08
	https://git.kernel.org/stable/c/91b9548d413fda488ea853cd1b9f59b572db3a0c
	https://git.kernel.org/stable/c/b4403cee6400c5f679e9c4a82b91d61aa961eccf