Subject: CVE-2022-48997: char: tpm: Protect tpm_pm_suspend with locks

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

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

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

char: tpm: Protect tpm_pm_suspend with locks

Currently tpm transactions are executed unconditionally in
tpm_pm_suspend() function, which may lead to races with other tpm
accessors in the system.

Specifically, the hw_random tpm driver makes use of tpm_get_random(),
and this function is called in a loop from a kthread, which means it's
not frozen alongside userspace, and so can race with the work done
during system suspend:

  tpm tpm0: tpm_transmit: tpm_recv: error -52
  tpm tpm0: invalid TPM_STS.x 0xff, dumping stack for forensics
  CPU: 0 PID: 1 Comm: init Not tainted 6.1.0-rc5+ #135
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-20220807_005459-localhost 04/01/2014
  Call Trace:
   tpm_tis_status.cold+0x19/0x20
   tpm_transmit+0x13b/0x390
   tpm_transmit_cmd+0x20/0x80
   tpm1_pm_suspend+0xa6/0x110
   tpm_pm_suspend+0x53/0x80
   __pnp_bus_suspend+0x35/0xe0
   __device_suspend+0x10f/0x350

Fix this by calling tpm_try_get_ops(), which itself is a wrapper around
tpm_chip_start(), but takes the appropriate mutex.

[Jason: reworked commit message, added metadata]

The Linux kernel CVE team has assigned CVE-2022-48997 to this issue.

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

	Issue introduced in 5.1 with commit e891db1a18bf and fixed in 5.4.226 with commit d699373ac5f3
	Issue introduced in 5.1 with commit e891db1a18bf and fixed in 5.10.158 with commit 4e0d6c687c92
	Issue introduced in 5.1 with commit e891db1a18bf and fixed in 5.15.82 with commit 571b6bbbf54d
	Issue introduced in 5.1 with commit e891db1a18bf and fixed in 6.0.12 with commit 25b78bf98b07
	Issue introduced in 5.1 with commit e891db1a18bf and fixed in 6.1 with commit 23393c646142

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-2022-48997
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/char/tpm/tpm-interface.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/d699373ac5f3545243d3c73a1ccab77fdef8cec6
	https://git.kernel.org/stable/c/4e0d6c687c925e27fd4bc78a2721d10acf5614d6
	https://git.kernel.org/stable/c/571b6bbbf54d835ea6120f65575cb55cd767e603
	https://git.kernel.org/stable/c/25b78bf98b07ff5aceb9b1e24f72ec0236c5c053
	https://git.kernel.org/stable/c/23393c6461422df5bf8084a086ada9a7e17dc2ba