Subject: CVE-2021-46994: can: mcp251x: fix resume from sleep before interface was brought up

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

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

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

can: mcp251x: fix resume from sleep before interface was brought up

Since 8ce8c0abcba3 the driver queues work via priv->restart_work when
resuming after suspend, even when the interface was not previously
enabled. This causes a null dereference error as the workqueue is only
allocated and initialized in mcp251x_open().

To fix this we move the workqueue init to mcp251x_can_probe() as there
is no reason to do it later and repeat it whenever mcp251x_open() is
called.

[mkl: fix error handling in mcp251x_stop()]

The Linux kernel CVE team has assigned CVE-2021-46994 to this issue.

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

	Issue introduced in 5.5 with commit 8ce8c0abcba3 and fixed in 5.10.38 with commit eecb4df8ec9f
	Issue introduced in 5.5 with commit 8ce8c0abcba3 and fixed in 5.11.22 with commit 6f8f1c27b577
	Issue introduced in 5.5 with commit 8ce8c0abcba3 and fixed in 5.12.5 with commit e1e10a390fd9
	Issue introduced in 5.5 with commit 8ce8c0abcba3 and fixed in 5.13 with commit 03c427147b2d

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-2021-46994
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/can/spi/mcp251x.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/eecb4df8ec9f896b19ee05bfa632ac6c1dcd8f21
	https://git.kernel.org/stable/c/6f8f1c27b577de15f69fefce3c502bb6300d825c
	https://git.kernel.org/stable/c/e1e10a390fd9479209c4d834d916ca5e6d5d396b
	https://git.kernel.org/stable/c/03c427147b2d3e503af258711af4fc792b89b0af