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tpm_tis: fix potential buffer overruns caused by bit glitches on the bus
authorJeremy Boone <jeremy.boone@nccgroup.trust>
Thu, 8 Feb 2018 20:32:06 +0000 (12:32 -0800)
committerJames Morris <james.morris@microsoft.com>
Mon, 26 Feb 2018 23:43:43 +0000 (15:43 -0800)
commit6bb320ca4a4a7b5b3db8c8d7250cc40002046878
tree9601fd6f7b998819060849d7a117ec5af5f99b92
parent4c3579f6cadd5eb8250a36e789e6df66f660237a
tpm_tis: fix potential buffer overruns caused by bit glitches on the bus

Discrete TPMs are often connected over slow serial buses which, on
some platforms, can have glitches causing bit flips.  In all the
driver _recv() functions, we need to use a u32 to unmarshal the
response size, otherwise a bit flip of the 31st bit would cause the
expected variable to go negative, which would then try to read a huge
amount of data.  Also sanity check that the expected amount of data is
large enough for the TPM header.

Signed-off-by: Jeremy Boone <jeremy.boone@nccgroup.trust>
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
drivers/char/tpm/tpm_tis_core.c