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char: tpm: Protect tpm_pm_suspend with locks

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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.

Signed-off-by: Jan Dabros <jsd@semihalf.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Tested-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/all/c5ba47ef-393f-1fba-30bd-1230d1b4b592@suse.cz/
Cc: stable@vger.kernel.org
Fixes: e891db1a18 ("tpm: turn on TPM on suspend for TPM 1.x")
[Jason: reworked commit message, added metadata]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Dabros 2022-11-28 20:56:51 +01:00 committed by Linus Torvalds
parent 0c3b5bcb48
commit 23393c6461
1 changed files with 3 additions and 2 deletions
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5
drivers/char/tpm/tpm-interface.c
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@ -401,13 +401,14 @@ int tpm_pm_suspend(struct device *dev)
!pm_suspend_via_firmware())
goto suspended;
if (!tpm_chip_start(chip)) {
rc = tpm_try_get_ops(chip);
if (!rc) {
if (chip->flags & TPM_CHIP_FLAG_TPM2)
tpm2_shutdown(chip, TPM2_SU_STATE);
else
rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
tpm_chip_stop(chip);
tpm_put_ops(chip);
}
suspended: