Some SPI controller drivers unregister the controller in the shutdown handler (e.g. BCM2835). If such a controller is used with a TPM 2 slave chip->ops may be accessed when it is already NULL:
At system shutdown the pre-shutdown handler tpm_class_shutdown() shuts down TPM 2 and sets chip->ops to NULL. Then at SPI controller unregistration tpm_tis_spi_remove() is called and eventually calls tpm_del_char_device() which tries to shut down TPM 2 again. Thereby it accesses chip->ops again: (tpm_del_char_device calls tpm_chip_start which calls tpm_clk_enable which calls chip->ops->clk_enable).
Avoid the NULL pointer access by testing if chip->ops is valid and skipping the TPM 2 shutdown procedure in case it is NULL.
Fixes: dcbeab1946454 ("tpm: fix crash in tpm_tis deinitialization") Cc: stable@vger.kernel.org Signed-off-by: Lino Sanfilippo LinoSanfilippo@gmx.de ---
Changes to v2: - rephrased the commit message to clarify the circumstances under which this bug triggers (as requested by Jarkko)
I was able to reproduce this issue with a SLB 9670 TPM chip controlled by a BCM2835 SPI controller.
The approach to fix this issue in the BCM2835 driver was rejected after a discussion on the mailing list:
https://marc.info/?l=linux-integrity&m=163285906725367&w=2
The reason for the rejection was the realization, that this issue should rather be fixed in the TPM code:
https://marc.info/?l=linux-spi&m=163311087423271&w=2
So this is the reworked version of a patch that is supposed to do that.
drivers/char/tpm/tpm-chip.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb7e109..7960da490e72 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -474,13 +474,19 @@ static void tpm_del_char_device(struct tpm_chip *chip)
/* Make the driver uncallable. */ down_write(&chip->ops_sem); - if (chip->flags & TPM_CHIP_FLAG_TPM2) { - if (!tpm_chip_start(chip)) { - tpm2_shutdown(chip, TPM2_SU_CLEAR); - tpm_chip_stop(chip); + /* Check if chip->ops is still valid: In case that the controller + * drivers shutdown handler unregisters the controller in its + * shutdown handler we are called twice and chip->ops to NULL. + */ + if (chip->ops) { + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + if (!tpm_chip_start(chip)) { + tpm2_shutdown(chip, TPM2_SU_CLEAR); + tpm_chip_stop(chip); + } } + chip->ops = NULL; } - chip->ops = NULL; up_write(&chip->ops_sem); }
base-commit: a7904a538933c525096ca2ccde1e60d0ee62c08e
Hi,
the patch below should also fix the issue that Stefan reported here:
https://marc.info/?l=linux-integrity&m=163927245509564&w=2
Regards, Lino
On 20.12.21 at 16:06, Lino Sanfilippo wrote:
Some SPI controller drivers unregister the controller in the shutdown handler (e.g. BCM2835). If such a controller is used with a TPM 2 slave chip->ops may be accessed when it is already NULL:
At system shutdown the pre-shutdown handler tpm_class_shutdown() shuts down TPM 2 and sets chip->ops to NULL. Then at SPI controller unregistration tpm_tis_spi_remove() is called and eventually calls tpm_del_char_device() which tries to shut down TPM 2 again. Thereby it accesses chip->ops again: (tpm_del_char_device calls tpm_chip_start which calls tpm_clk_enable which calls chip->ops->clk_enable).
Avoid the NULL pointer access by testing if chip->ops is valid and skipping the TPM 2 shutdown procedure in case it is NULL.
Fixes: dcbeab1946454 ("tpm: fix crash in tpm_tis deinitialization") Cc: stable@vger.kernel.org Signed-off-by: Lino Sanfilippo LinoSanfilippo@gmx.de
Changes to v2:
- rephrased the commit message to clarify the circumstances under which this bug triggers (as requested by Jarkko)
I was able to reproduce this issue with a SLB 9670 TPM chip controlled by a BCM2835 SPI controller.
The approach to fix this issue in the BCM2835 driver was rejected after a discussion on the mailing list:
https://marc.info/?l=linux-integrity&m=163285906725367&w=2
The reason for the rejection was the realization, that this issue should rather be fixed in the TPM code:
https://marc.info/?l=linux-spi&m=163311087423271&w=2
So this is the reworked version of a patch that is supposed to do that.
drivers/char/tpm/tpm-chip.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb7e109..7960da490e72 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -474,13 +474,19 @@ static void tpm_del_char_device(struct tpm_chip *chip)
/* Make the driver uncallable. */ down_write(&chip->ops_sem);
- if (chip->flags & TPM_CHIP_FLAG_TPM2) {
if (!tpm_chip_start(chip)) {tpm2_shutdown(chip, TPM2_SU_CLEAR);tpm_chip_stop(chip);
- /* Check if chip->ops is still valid: In case that the controller
* drivers shutdown handler unregisters the controller in its* shutdown handler we are called twice and chip->ops to NULL.*/- if (chip->ops) {
if (chip->flags & TPM_CHIP_FLAG_TPM2) {if (!tpm_chip_start(chip)) {tpm2_shutdown(chip, TPM2_SU_CLEAR);tpm_chip_stop(chip);}chip->ops = NULL;
- chip->ops = NULL; up_write(&chip->ops_sem);
}
base-commit: a7904a538933c525096ca2ccde1e60d0ee62c08e
On 12/20/21 10:06, Lino Sanfilippo wrote:
Some SPI controller drivers unregister the controller in the shutdown handler (e.g. BCM2835). If such a controller is used with a TPM 2 slave chip->ops may be accessed when it is already NULL:
At system shutdown the pre-shutdown handler tpm_class_shutdown() shuts down TPM 2 and sets chip->ops to NULL. Then at SPI controller unregistration tpm_tis_spi_remove() is called and eventually calls tpm_del_char_device() which tries to shut down TPM 2 again. Thereby it accesses chip->ops again: (tpm_del_char_device calls tpm_chip_start which calls tpm_clk_enable which calls chip->ops->clk_enable).
Avoid the NULL pointer access by testing if chip->ops is valid and skipping the TPM 2 shutdown procedure in case it is NULL.
Fixes: dcbeab1946454 ("tpm: fix crash in tpm_tis deinitialization") Cc: stable@vger.kernel.org Signed-off-by: Lino Sanfilippo LinoSanfilippo@gmx.de
Changes to v2:
- rephrased the commit message to clarify the circumstances under which this bug triggers (as requested by Jarkko)
I was able to reproduce this issue with a SLB 9670 TPM chip controlled by a BCM2835 SPI controller.
The approach to fix this issue in the BCM2835 driver was rejected after a discussion on the mailing list:
https://marc.info/?l=linux-integrity&m=163285906725367&w=2
The reason for the rejection was the realization, that this issue should rather be fixed in the TPM code:
https://marc.info/?l=linux-spi&m=163311087423271&w=2
So this is the reworked version of a patch that is supposed to do that.
drivers/char/tpm/tpm-chip.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb7e109..7960da490e72 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -474,13 +474,19 @@ static void tpm_del_char_device(struct tpm_chip *chip) /* Make the driver uncallable. */ down_write(&chip->ops_sem);
- if (chip->flags & TPM_CHIP_FLAG_TPM2) {
if (!tpm_chip_start(chip)) {tpm2_shutdown(chip, TPM2_SU_CLEAR);tpm_chip_stop(chip);
- /* Check if chip->ops is still valid: In case that the controller
* drivers shutdown handler unregisters the controller in its* shutdown handler we are called twice and chip->ops to NULL.*/- if (chip->ops) {
if (chip->flags & TPM_CHIP_FLAG_TPM2) {if (!tpm_chip_start(chip)) {tpm2_shutdown(chip, TPM2_SU_CLEAR);tpm_chip_stop(chip);}chip->ops = NULL;
- chip->ops = NULL; up_write(&chip->ops_sem); }
base-commit: a7904a538933c525096ca2ccde1e60d0ee62c08e
Fixes: 39d0099f9439 ("powerpc/pseries: Add shutdown() to vio_driver and vio_bus")
Reviewed-by: Stefan Berger stefanb@linux.ibm.com
Tested-by: Stefan Berger stefanb@linux.ibm.com
Hi Stefan,
On 22.12.21 at 05:53, Stefan Berger wrote:
drivers/char/tpm/tpm-chip.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb7e109..7960da490e72 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -474,13 +474,19 @@ static void tpm_del_char_device(struct tpm_chip *chip) /* Make the driver uncallable. */ down_write(&chip->ops_sem); - if (chip->flags & TPM_CHIP_FLAG_TPM2) { - if (!tpm_chip_start(chip)) { - tpm2_shutdown(chip, TPM2_SU_CLEAR); - tpm_chip_stop(chip); + /* Check if chip->ops is still valid: In case that the controller + * drivers shutdown handler unregisters the controller in its + * shutdown handler we are called twice and chip->ops to NULL. + */ + if (chip->ops) { + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + if (!tpm_chip_start(chip)) { + tpm2_shutdown(chip, TPM2_SU_CLEAR); + tpm_chip_stop(chip); + } } + chip->ops = NULL; } - chip->ops = NULL; up_write(&chip->ops_sem); } base-commit: a7904a538933c525096ca2ccde1e60d0ee62c08e
Fixes: 39d0099f9439 ("powerpc/pseries: Add shutdown() to vio_driver and vio_bus")
Reviewed-by: Stefan Berger stefanb@linux.ibm.com
Tested-by: Stefan Berger stefanb@linux.ibm.com
Thanks a lot for testing this.
Best regards, Lino
On Mon, Dec 20, 2021 at 04:06:35PM +0100, Lino Sanfilippo wrote:
Some SPI controller drivers unregister the controller in the shutdown handler (e.g. BCM2835). If such a controller is used with a TPM 2 slave chip->ops may be accessed when it is already NULL:
At system shutdown the pre-shutdown handler tpm_class_shutdown() shuts down TPM 2 and sets chip->ops to NULL. Then at SPI controller unregistration tpm_tis_spi_remove() is called and eventually calls tpm_del_char_device() which tries to shut down TPM 2 again. Thereby it accesses chip->ops again: (tpm_del_char_device calls tpm_chip_start which calls tpm_clk_enable which calls chip->ops->clk_enable).
Avoid the NULL pointer access by testing if chip->ops is valid and skipping the TPM 2 shutdown procedure in case it is NULL.
Fixes: dcbeab1946454 ("tpm: fix crash in tpm_tis deinitialization") Cc: stable@vger.kernel.org Signed-off-by: Lino Sanfilippo LinoSanfilippo@gmx.de
Thank you.
Reviewed-by: Jarkko Sakkinen jarkko@kernel.org
BR, Jarkko
Hi,
On 29.12.21 at 01:13, Jarkko Sakkinen wrote:
On Mon, Dec 20, 2021 at 04:06:35PM +0100, Lino Sanfilippo wrote:
Some SPI controller drivers unregister the controller in the shutdown handler (e.g. BCM2835). If such a controller is used with a TPM 2 slave chip->ops may be accessed when it is already NULL:
At system shutdown the pre-shutdown handler tpm_class_shutdown() shuts down TPM 2 and sets chip->ops to NULL. Then at SPI controller unregistration tpm_tis_spi_remove() is called and eventually calls tpm_del_char_device() which tries to shut down TPM 2 again. Thereby it accesses chip->ops again: (tpm_del_char_device calls tpm_chip_start which calls tpm_clk_enable which calls chip->ops->clk_enable).
Avoid the NULL pointer access by testing if chip->ops is valid and skipping the TPM 2 shutdown procedure in case it is NULL.
Fixes: dcbeab1946454 ("tpm: fix crash in tpm_tis deinitialization") Cc: stable@vger.kernel.org Signed-off-by: Lino Sanfilippo LinoSanfilippo@gmx.de
Thank you.
Reviewed-by: Jarkko Sakkinen jarkko@kernel.org
BR, Jarkko
Thanks a lot for the review. Please note that the latest version is v3 which contains one more Fixes tag and also a tag for the review by Stefan. I also adjusted the source code comment in that version which I somehow messed up in v2.
Regards, Lino
On Wed, Dec 29, 2021 at 02:41:52AM +0100, Lino Sanfilippo wrote:
Hi,
On 29.12.21 at 01:13, Jarkko Sakkinen wrote:
On Mon, Dec 20, 2021 at 04:06:35PM +0100, Lino Sanfilippo wrote:
Some SPI controller drivers unregister the controller in the shutdown handler (e.g. BCM2835). If such a controller is used with a TPM 2 slave chip->ops may be accessed when it is already NULL:
At system shutdown the pre-shutdown handler tpm_class_shutdown() shuts down TPM 2 and sets chip->ops to NULL. Then at SPI controller unregistration tpm_tis_spi_remove() is called and eventually calls tpm_del_char_device() which tries to shut down TPM 2 again. Thereby it accesses chip->ops again: (tpm_del_char_device calls tpm_chip_start which calls tpm_clk_enable which calls chip->ops->clk_enable).
Avoid the NULL pointer access by testing if chip->ops is valid and skipping the TPM 2 shutdown procedure in case it is NULL.
Fixes: dcbeab1946454 ("tpm: fix crash in tpm_tis deinitialization") Cc: stable@vger.kernel.org Signed-off-by: Lino Sanfilippo LinoSanfilippo@gmx.de
Thank you.
Reviewed-by: Jarkko Sakkinen jarkko@kernel.org
BR, Jarkko
Thanks a lot for the review. Please note that the latest version is v3 which contains one more Fixes tag and also a tag for the review by Stefan. I also adjusted the source code comment in that version which I somehow messed up in v2.
Since there is no functional difference, I rather do not swap it.
I fixed a glitch:
+ + /*
A multi-line commit needs to have this as the very first line. You can check if the all tags were pulled by b4.
/Jarkko
On 29.12.21 at 02:46, Jarkko Sakkinen wrote:
Since there is no functional difference, I rather do not swap it.
I fixed a glitch:
/*A multi-line commit needs to have this as the very first line. You can check if the all tags were pulled by b4.
/Jarkko
I see, thanks for fixing the comment then.
Regards, Lino
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