static int hwrand(uint8_t *buf, const size_t len) {
if (!have_rdrand()) {
return 0;
}
const size_t len_multiple8 = len & ~7;
if (!CRYPTO_rdrand_multiple8_buf(buf, len_multiple8)) {
return 0;
}
const size_t remainder = len - len_multiple8;
if (remainder != 0) {
assert(remainder < 8);
uint8_t rand_buf[8];
if (!CRYPTO_rdrand(rand_buf)) {
return 0;
}
OPENSSL_memcpy(buf + len_multiple8, rand_buf, remainder);
}
#if defined(BORINGSSL_FIPS_BREAK_CRNG)
// This breaks the "continuous random number generator test" defined in FIPS
// 140-2, section 4.9.2, and implemented in rand_get_seed().
OPENSSL_memset(buf, 0, len);
#endif
return 1;
}
int CRYPTO_hwrand(uint8_t *buf, size_t len) {
if (!have_rdrand()) {
return 0;
}
const size_t len_multiple8 = len & ~7;
if (!CRYPTO_rdrand_multiple8_buf(buf, len_multiple8)) {
return 0;
}
len -= len_multiple8;
if (len != 0) {
assert(len < 8);
uint8_t rand_buf[8];
if (!CRYPTO_rdrand(rand_buf)) {
return 0;
}
memcpy(buf + len_multiple8, rand_buf, len);
}
return 1;
}