[PATCH 5.14 021/849] tpm: Check for integer overflow in tpm2_map_response_body()

Greg Kroah-Hartman
2021-11-15T21:21:40Z

From: Dan Carpenter <dan.carpenter@oracle.com>

commit a0bcce2b2a169e10eb265c8f0ebdd5ae4c875670 upstream.

The "4 * be32_to_cpu(data->count)" multiplication can potentially
overflow which would lead to memory corruption. Add a check for that.

Cc: stable@vger.kernel.org
Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/char/tpm/tpm2-space.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -455,6 +455,9 @@ static int tpm2_map_response_body(struct
if (be32_to_cpu(data->capability) != TPM2_CAP_HANDLES)
return 0;

+ if (be32_to_cpu(data->count) > (UINT_MAX - TPM_HEADER_SIZE - 9) / 4)
+ return -EFAULT;
+
if (len != TPM_HEADER_SIZE + 9 + 4 * be32_to_cpu(data->count))
return -EFAULT;