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tpm: fix potential buffer overruns caused by bit glitches on the bus

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Discrete TPMs are often connected over slow serial buses which, on
some platforms, can have glitches causing bit flips.  If a bit does
flip it could cause an overrun if it's in one of the size parameters,
so sanity check that we're not overrunning the provided buffer when
doing a memcpy().

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>
Tested-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>
This commit is contained in:
Jeremy Boone 2018-02-08 12:28:08 -08:00 committed by James Morris
parent 6d24cd186d
commit 3be2327475
2 changed files with 8 additions and 0 deletions
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4
drivers/char/tpm/tpm-interface.c
View File

@ -1190,6 +1190,10 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
break;
recd = be32_to_cpu(tpm_cmd.params.getrandom_out.rng_data_len);
if (recd > num_bytes) {
total = -EFAULT;
break;
}
rlength = be32_to_cpu(tpm_cmd.header.out.length);
if (rlength < offsetof(struct tpm_getrandom_out, rng_data) +

4
drivers/char/tpm/tpm2-cmd.c
View File

@ -683,6 +683,10 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
if (!rc) {
data_len = be16_to_cpup(
(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
if (data_len < MIN_KEY_SIZE || data_len > MAX_KEY_SIZE + 1) {
rc = -EFAULT;
goto out;
}
rlength = be32_to_cpu(((struct tpm2_cmd *)&buf)
->header.out.length);