tpm: Check for integer overflow in tpm2_map_response_body()

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>

diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 9f4e22dcde2704732c98a34a8f2adc0b10cd3ec8..205d930d7ea60ea7aba021a3b1a984a65e91c9bb 100644 (file)
--- 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 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;