Fix a race condition in drbg_add
@@ -1079,6 +1079,7 @@ static int drbg_add(const void *buf, int num, double randomness)
if (num < 0 || randomness < 0.0)
return 0;
+ rand_drbg_lock(drbg);
seedlen = rand_drbg_seedlen(drbg);
buflen = (size_t)num;
@@ -1090,10 +1091,13 @@ static int drbg_add(const void *buf, int num, double randomness)
* inevitably. So we use a trick to mix the buffer contents into
* the DRBG state without forcing a reseeding: we generate a
* dummy random byte, using the buffer content as additional data.
+ * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
*/
unsigned char dummy[1];
- return RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
+ ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
+ rand_drbg_unlock(drbg);
+ return ret;
#else
/*
* If an os entropy source is avaible then we declare the buffer content
@@ -1117,7 +1121,6 @@ static int drbg_add(const void *buf, int num, double randomness)
randomness = (double)seedlen;
}
- rand_drbg_lock(drbg);
ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
rand_drbg_unlock(drbg);
