tpm: add check for minimum buffer size in tpm_transmit()

tpm_transmit() does not check that bufsiz is at least TPM_HEADER_SIZE
before accessing data. This commit adds this check and returns -EINVAL
if it fails.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 3970f843acd1..8de61876f633 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -337,6 +337,9 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
         u32 count, ordinal;
         unsigned long stop;
 
+        if (bufsiz < TPM_HEADER_SIZE)
+                return -EINVAL;
+
         if (bufsiz > TPM_BUFSIZE)
                 bufsiz = TPM_BUFSIZE;