third_party/WebKit/Source/wtf/CryptographicallyRandomNumber.cpp

/*
 * Copyright (c) 1996, David Mazieres <dm@uun.org>
 * Copyright (c) 2008, Damien Miller <djm@openbsd.org>
 *
 * Permission to use, copy, modify, and 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 "wtf/CryptographicallyRandomNumber.h"

#include "base/rand_util.h"
#include <string.h>

namespace WTF {

static bool s_shouldUseAlwaysZeroRandomSourceForTesting = false;

void setAlwaysZeroRandomSourceForTesting()
{
    s_shouldUseAlwaysZeroRandomSourceForTesting = true;
}

uint32_t cryptographicallyRandomNumber()
{
    uint32_t result;
    cryptographicallyRandomValues(&result, sizeof(result));
    return result;
}

void cryptographicallyRandomValues(void* buffer, size_t length)
{
    if (s_shouldUseAlwaysZeroRandomSourceForTesting) {
        memset(buffer, '\0', length);
        return;
    }

    // This should really be crypto::RandBytes(), but WTF can't depend on crypto. The implementation of
    // crypto::RandBytes() is just calling base::RandBytes(), so both are actually same.
    base::RandBytes(buffer, length);
}

} // namespace WTF