[PATCH 4.19 010/323] tpm: Check for integer overflow in tpm2_map_response_body()

[Greg Kroah-Hartman]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

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@xxxxxxxxxxxxxxx
Fixes: 745b361e989a ("tpm: infrastructure for TPM spaces")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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
@@ -419,6 +419,9 @@ 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;