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/* Copyright (c) 2015, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/rand.h>
#include <assert.h>
#include <string.h>
#include <openssl/cpu.h>
#include "internal.h"
#if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM)
/* These functions are defined in asm/rdrand-x86_64.pl */
extern int CRYPTO_rdrand(uint8_t out[8]);
extern int CRYPTO_rdrand_multiple8_buf(uint8_t *buf, size_t len);
static int have_rdrand(void) {
return (OPENSSL_ia32cap_P[1] & (1u << 30)) != 0;
}
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;
}
#else
int CRYPTO_hwrand(uint8_t *buf, size_t len) {
return 0;
}
#endif
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