CVE-2021-47120: HID: magicmouse: fix NULL-deref on disconnect

CVE-2021-47120: HID: magicmouse: fix NULL-deref on disconnect

[Greg Kroah-Hartman]

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

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

HID: magicmouse: fix NULL-deref on disconnect

Commit 9d7b18668956 ("HID: magicmouse: add support for Apple Magic
Trackpad 2") added a sanity check for an Apple trackpad but returned
success instead of -ENODEV when the check failed. This means that the
remove callback will dereference the never-initialised driver data
pointer when the driver is later unbound (e.g. on USB disconnect).

The Linux kernel CVE team has assigned CVE-2021-47120 to this issue.


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

	Issue introduced in 4.20 with commit 9d7b18668956 and fixed in 5.4.125 with commit 368c5d45a87e
	Issue introduced in 4.20 with commit 9d7b18668956 and fixed in 5.10.43 with commit b5d013c4c76b
	Issue introduced in 4.20 with commit 9d7b18668956 and fixed in 5.12.10 with commit 9cf27473f219
	Issue introduced in 4.20 with commit 9d7b18668956 and fixed in 5.13 with commit 4b4f6cecca44

Please see https://www.kernel.org or 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-2021-47120
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/hid/hid-magicmouse.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/368c5d45a87e1bcc7f1e98e0c255c37b7b12c5d6
	https://git.kernel.org/stable/c/b5d013c4c76b276890135b5d32803c4c63924b77
	https://git.kernel.org/stable/c/9cf27473f21913a3eaf4702dd2a25415afd5f33f
	https://git.kernel.org/stable/c/4b4f6cecca446abcb686c6e6c451d4f1ec1a7497