Check return value of time() when getting additional data for the DRBG
GH:
@@ -229,9 +229,11 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
}
/*
- * Find a suitable system time. Start with the highest resolution source
+ * Find a suitable source of time. Start with the highest resolution source
* and work down to the slower ones. This is added as additional data and
* isn't counted as randomness, so any result is acceptable.
+ *
+ * Returns 0 when we weren't able to find any time source
*/
static uint64_t get_timer_bits(void)
{
@@ -286,7 +288,12 @@ static uint64_t get_timer_bits(void)
return TWO32TO64(tv.tv_sec, tv.tv_usec);
}
# endif
- return time(NULL);
+ {
+ time_t t = time(NULL);
+ if (t == (time_t)-1)
+ return 0;
+ return t;
+ }
#endif
}
@@ -329,6 +336,7 @@ size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len)
RAND_POOL_add(pool, (unsigned char *)&thread_id, sizeof(thread_id), 0);
tbits = get_timer_bits();
+ if (tbits != 0)
RAND_POOL_add(pool, (unsigned char *)&tbits, sizeof(tbits), 0);
/* TODO: Use RDSEED? */
