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tpm: st33zp24: 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>
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>
hifive-unleashed-5.1
Jeremy Boone 2018-02-08 12:29:09 -08:00 committed by James Morris
parent 9b8cb28d7c
commit 6d24cd186d
1 changed files with 2 additions and 2 deletions
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4
drivers/char/tpm/st33zp24/st33zp24.c
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@ -457,7 +457,7 @@ static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
size_t count)
{
int size = 0;
int expected;
u32 expected;
if (!chip)
return -EBUSY;
@ -474,7 +474,7 @@ static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
}
expected = be32_to_cpu(*(__be32 *)(buf + 2));
if (expected > count) {
if (expected > count || expected < TPM_HEADER_SIZE) {
size = -EIO;
goto out;
}