Messages in this thread | | | Subject | Re: [PATCH v5 6/7] tpm: ensure that the output of PCR read contains the correct digest size | From | Roberto Sassu <> | Date | Mon, 19 Nov 2018 16:09:34 +0100 |
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On 11/19/2018 3:33 PM, Jarkko Sakkinen wrote: > On Mon, Nov 19, 2018 at 09:14:00AM +0100, Roberto Sassu wrote: >> On 11/18/2018 8:32 AM, Jarkko Sakkinen wrote: >>> On Fri, Nov 16, 2018 at 05:06:48PM +0100, Roberto Sassu wrote: >>>> On 11/16/2018 2:41 PM, Jarkko Sakkinen wrote: >>>>> On Wed, Nov 14, 2018 at 04:31:07PM +0100, Roberto Sassu wrote: >>>>>> This patch protects against data corruption that could happen in the bus, >>>>>> by checking that that the digest size returned by the TPM during a PCR read >>>>>> matches the size of the algorithm passed to tpm2_pcr_read(). >>>>>> >>>>>> This check is performed after information about the PCR banks has been >>>>>> retrieved. >>>>>> >>>>>> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> >>>>>> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> >>>>>> Cc: stable@vger.kernel.org >>>>> >>>>> Missing fixes tag. >>>> >>>> Before this patch set, tpm2_pcr_extend() always copied 20 bytes from the >>>> output sent by the TPM. >>>> >>>> Roberto >>> >>> Aah, right, of course. Well the patch set is ATM somewhat broken because >>> this would require a fixes tag that points to a patch insdie the patch >>> set. >>> >>> Probably good way to fix the issue is to just merge this with the >>> earlier commit. >> >> Unfortunately, it is not possible. The exact digest size has been >> introduced with patch 5/7. > > I put this in simple terms: if I merge 5/7 the driver will be broken. > Any commit in the patch set should not leave the tree in broken state.
Patch 6/7 does not fix patch 5/7. The check in patch 6/7 is not done for the PCR read performed by patch 5/7, because the digest sizes are not yet available.
Roberto
> That implies that 5/7 and 6/7 cannot be separate commits. > > /Jarkko >
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