tpm: st33zp24: fix potential buffer overruns caused by bit glitches on the bus
authorJeremy Boone <jeremy.boone@nccgroup.trust>
Thu, 8 Feb 2018 20:29:09 +0000 (12:29 -0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 11 Mar 2018 15:21:27 +0000 (16:21 +0100)
commit9be164624e90d1d1b03200c7a749d9c72ad26f23
tree6af0e4fceb3190666554b0a93052123c6ce10bb8
parent6a83eb2354543e3263b880eb822c4b0993a2236b
tpm: st33zp24: fix potential buffer overruns caused by bit glitches on the bus

commit 6d24cd186d9fead3722108dec1b1c993354645ff upstream.

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>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/char/tpm/st33zp24/st33zp24.c