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: [email protected] Fixes: 745b361 ("tpm: infrastructure for TPM spaces") Signed-off-by: Dan Carpenter <[email protected]> Reviewed-by: Jarkko Sakkinen <[email protected]> Signed-off-by: Jarkko Sakkinen <[email protected]>
tuxedocomputers · Oct 26, 2021 · a0bcce2 · a0bcce2
1 parent 4091c00
commit a0bcce2
Showing 1 changed file with 3 additions and 0 deletions.
diff --git 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 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;