lkml.org 
[lkml]   [2022]   [Dec]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v3] char: tpm: Protect tpm_pm_suspend with locks
On Sun, Dec 04, 2022 at 05:06:41PM +0000, Jarkko Sakkinen wrote:
> On Mon, Nov 28, 2022 at 08:56:51PM +0100, Jason A. Donenfeld wrote:
> > From: Jan Dabros <jsd@semihalf.com>
> >
> > 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] <TASK>
> > [ 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 <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: e891db1a18bf ("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>
> > ---
> > 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:
> > --
> > 2.38.1
> >
>
> Hi, sorry for the latency.
>
> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

Applied to git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git

BR, Jarkko

\
 
 \ /
  Last update: 2022-12-04 18:12    [W:0.152 / U:0.676 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site