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Donenfeld" To: Vlastimil Babka , Jarkko Sakkinen , =?utf-8?b?SmFuIETEhWJyb8Wb?= , linux-integrity@vger.kernel.org, peterhuewe@gmx.de, jgg@ziepe.ca, gregkh@linuxfoundation.org, arnd@arndb.de, rrangel@chromium.org, timvp@google.com, apronin@google.com, mw@semihalf.com, upstream@semihalf.com, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org Cc: "Jason A . Donenfeld" , stable@vger.kernel.org Subject: [PATCH v3] char: tpm: Protect tpm_pm_suspend with locks Date: Mon, 28 Nov 2022 20:56:51 +0100 Message-Id: <20221128195651.322822-1-Jason@zx2c4.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Jan Dabros 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: [ 3.277834] tpm tpm0: tpm_transmit: tpm_recv: error -52 [ 3.278437] tpm tpm0: invalid TPM_STS.x 0xff, dumping stack for forensics [ 3.278445] CPU: 0 PID: 1 Comm: init Not tainted 6.1.0-rc5+ #135 [ 3.278450] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 [ 3.278453] Call Trace: [ 3.278458] [ 3.278460] dump_stack_lvl+0x34/0x44 [ 3.278471] tpm_tis_status.cold+0x19/0x20 [ 3.278479] tpm_transmit+0x13b/0x390 [ 3.278489] tpm_transmit_cmd+0x20/0x80 [ 3.278496] tpm1_pm_suspend+0xa6/0x110 [ 3.278503] tpm_pm_suspend+0x53/0x80 [ 3.278510] __pnp_bus_suspend+0x35/0xe0 [ 3.278515] ? pnp_bus_freeze+0x10/0x10 [ 3.278519] __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 Reported-by: Vlastimil Babka Tested-by: Jason A. Donenfeld Tested-by: Vlastimil Babka Link: https://lore.kernel.org/all/c5ba47ef-393f-1fba-30bd-1230d1b4b592@suse.cz/ Cc: stable@vger.kernel.org Fixes: e891db1a18bf ("tpm: turn on TPM on suspend for TPM 1.x") [Jason: reworked commit message, added metadata] Signed-off-by: Jason A. Donenfeld Reviewed-by: Jarkko Sakkinen --- drivers/char/tpm/tpm-interface.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 1621ce818705..d69905233aff 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -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: