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]

kernel.org https://git.kernel.org/stable/c/23393c6461422df5bf8084a086ada9a7e17dc2ba [No types assigned]

kernel.org https://git.kernel.org/stable/c/25b78bf98b07ff5aceb9b1e24f72ec0236c5c053 [No types assigned]

kernel.org https://git.kernel.org/stable/c/4e0d6c687c925e27fd4bc78a2721d10acf5614d6 [No types assigned]

kernel.org https://git.kernel.org/stable/c/571b6bbbf54d835ea6120f65575cb55cd767e603 [No types assigned]

kernel.org https://git.kernel.org/stable/c/d699373ac5f3545243d3c73a1ccab77fdef8cec6 [No types assigned]