From 3be23274755ee85771270a23af7691dc9b3a95db Mon Sep 17 00:00:00 2001
From: Jeremy Boone <jeremy.boone@nccgroup.trust>
Date: Thu, 8 Feb 2018 12:28:08 -0800
Subject: [PATCH] tpm: fix potential buffer overruns caused by bit glitches on
the bus
References: bsc#1082555
Patch-mainline: v4.16-rc4
Git-commit: 3be23274755ee85771270a23af7691dc9b3a95db
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>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
drivers/char/tpm/tpm-interface.c | 4 ++++
drivers/char/tpm/tpm2-cmd.c | 4 ++++
2 files changed, 8 insertions(+)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 76df4fbcf089..9e80a953d693 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -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) +
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index c17e75348a99..a700f8f9ead7 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -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);
--
2.13.6