From: Jeremy Boone <jeremy.boone@nccgroup.trust>
commit c8e3e06d252155ad0e38a64a65ebb85638893025 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@xxxxxxxxxxxxxxx
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
Backport for v4.9 because of the merge conflict.
drivers/char/tpm/tpm-interface.c | 5 +++++
drivers/char/tpm/tpm2-cmd.c | 6 ++++++
2 files changed, 11 insertions(+)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index d0ac2d56520f..830d7e30e508 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1078,6 +1078,11 @@ 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;
+ }
+
memcpy(dest, tpm_cmd.params.getrandom_out.rng_data, recd);
dest += recd;
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 17896d654033..a5780ebe15ef 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -668,6 +668,11 @@ 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;
+ }
+
data = &buf.data[TPM_HEADER_SIZE + 6];
memcpy(payload->key, data, data_len - 1);
@@ -675,6 +680,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
payload->migratable = data[data_len - 1];
}
+out:
tpm_buf_destroy(&buf);
return rc;
}
--
2.15.1