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)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 11 Mar 2018 15:21:27 +0000 (16:21 +0100)
commit922f22e680e2ed1277b53f8e183265b71b5dfcf3
treeeceb82e3b7ed5dcc5cb34b1a6efbc62ed92a423e
parent15dcd3aa1542a1f00df25dd741200c720b870793
tpm_tis: fix potential buffer overruns caused by bit glitches on the bus

commit 6bb320ca4a4a7b5b3db8c8d7250cc40002046878 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>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/char/tpm/tpm_tis_core.c