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

commit 3be23274755ee85771270a23af7691dc9b3a95db upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1d6729be4cd6376727b9b210319bd77f03ccfb02..3cec403a80b32539861d0e975803723fccaa7e2c 100644 (file)
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1228,6 +1228,10 @@ int tpm_get_random(u32 chip_num, 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 e1a41b788f081c829ad0d0353ac7d3622752c82f..44a3d16231f6259555f1fde509e09e5282f1e896 100644 (file)
--- 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);