tpm: fix potential buffer overruns caused by bit glitches on the bus

[sfrench/cifs-2.6.git] / drivers / char / tpm / tpm-interface.c

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 76df4fbcf089c2371b2ad8b08f31bf446b5c488b..9e80a953d6933ea05668636b6abcd444eff72b0a 100644 (file)
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1190,6 +1190,10 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
                        break;
 
                recd = be32_to_cpu(tpm_cmd.params.getrandom_out.rng_data_len);
+               if (recd > num_bytes) {
+                       total = -EFAULT;
+                       break;
+               }
 
                rlength = be32_to_cpu(tpm_cmd.header.out.length);
                if (rlength < offsetof(struct tpm_getrandom_out, rng_data) +