1be2ec6756
Since the caller must check for CRYPTO_hwrand failures anyway, there's not much point in doing the CRYPTO_have_hwrand check externally. (As a bonus, CRYPTO_hwrand no longer compiles to abort() on ARM, so linker deduplicating won't confuse Chrome's crash reporter...) Change-Id: I2191d835fbda5b70812f14cd9a873a5e35c30c6d Reviewed-on: https://boringssl-review.googlesource.com/5630 Reviewed-by: Adam Langley <agl@google.com>
66 lines
1.7 KiB
C
66 lines
1.7 KiB
C
/* Copyright (c) 2015, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#include <openssl/rand.h>
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#include <assert.h>
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#include <string.h>
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#include <openssl/cpu.h>
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#include "internal.h"
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#if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM)
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/* These functions are defined in asm/rdrand-x86_64.pl */
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extern int CRYPTO_rdrand(uint8_t out[8]);
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extern int CRYPTO_rdrand_multiple8_buf(uint8_t *buf, size_t len);
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static int have_rdrand(void) {
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return (OPENSSL_ia32cap_P[1] & (1u << 30)) != 0;
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}
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int CRYPTO_hwrand(uint8_t *buf, size_t len) {
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if (!have_rdrand()) {
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return 0;
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}
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const size_t len_multiple8 = len & ~7;
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if (!CRYPTO_rdrand_multiple8_buf(buf, len_multiple8)) {
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return 0;
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}
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len -= len_multiple8;
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if (len != 0) {
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assert(len < 8);
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uint8_t rand_buf[8];
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if (!CRYPTO_rdrand(rand_buf)) {
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return 0;
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}
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memcpy(buf + len_multiple8, rand_buf, len);
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}
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return 1;
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}
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#else
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int CRYPTO_hwrand(uint8_t *buf, size_t len) {
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return 0;
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}
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#endif
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