diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index caf8012ef47ce1c69af6f07df4f62e7c5676a581..1fe9793358357390c1a25fbafd4f79cb9515551a 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -383,6 +383,9 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
 	u32 count, ordinal;
 	unsigned long stop;
 
+	if (bufsiz > TPM_BUFSIZE)
+		bufsiz = TPM_BUFSIZE;
+
 	count = be32_to_cpu(*((__be32 *) (buf + 2)));
 	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
 	if (count == 0)