tpm: Check for integer overflow in tpm2_map_response_body()

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: 745b361e ("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>

drivers/char/tpm/tpm2-space.c

@@ -455,6 +455,9 @@ static int tpm2_map_response_body(struct tpm_chip *chip, u32 cc, u8 *rsp,
 	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;