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>
Sat, 24 Mar 2018 09:58:39 +0000 (10:58 +0100)
commit34e924e599909b078c90d3bad982cb49d8290689
treee2a22f21436ee12edd70b16cc4baf1ea87ac43a3
parenta5291a8c6d00dced63310502343aa979a5c5674c
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.c