1 /* Copyright (c) 2020, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15 #include <openssl/base.h>
16 #include "../fipsmodule/rand/internal.h"
17
18 #if defined(BORINGSSL_FIPS_PASSIVE_ENTROPY)
19
20 // RAND_need_entropy is called by the FIPS module when it has blocked because of
21 // a lack of entropy. This signal is used as an indication to feed it more.
RAND_need_entropy(size_t bytes_needed)22 void RAND_need_entropy(size_t bytes_needed) {
23 uint8_t buf[CTR_DRBG_ENTROPY_LEN * BORINGSSL_FIPS_OVERREAD];
24 size_t todo = sizeof(buf);
25 if (todo > bytes_needed) {
26 todo = bytes_needed;
27 }
28
29 int used_cpu;
30 CRYPTO_get_seed_entropy(buf, todo, &used_cpu);
31 RAND_load_entropy(buf, todo, used_cpu);
32 }
33
34 #endif // BORINGSSL_FIPS_PASSIVE_ENTROPY
35