openssl/crypto/rand/rand_lib.c

/* crypto/rand/rand_lib.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include <time.h>
#include "internal/cryptlib.h"
#include <openssl/rand.h>

#ifndef OPENSSL_NO_ENGINE
# include <openssl/engine.h>
#endif

#ifdef OPENSSL_FIPS
# include <openssl/fips.h>
# include <openssl/fips_rand.h>
#endif

#ifndef OPENSSL_NO_ENGINE
/* non-NULL if default_RAND_meth is ENGINE-provided */
static ENGINE *funct_ref = NULL;
#endif
static const RAND_METHOD *default_RAND_meth = NULL;

int RAND_set_rand_method(const RAND_METHOD *meth)
{
#ifndef OPENSSL_NO_ENGINE
    if (funct_ref) {
        ENGINE_finish(funct_ref);
        funct_ref = NULL;
    }
#endif
    default_RAND_meth = meth;
    return 1;
}

const RAND_METHOD *RAND_get_rand_method(void)
{
    if (!default_RAND_meth) {
#ifndef OPENSSL_NO_ENGINE
        ENGINE *e = ENGINE_get_default_RAND();
        if (e) {
            default_RAND_meth = ENGINE_get_RAND(e);
            if (!default_RAND_meth) {
                ENGINE_finish(e);
                e = NULL;
            }
        }
        if (e)
            funct_ref = e;
        else
#endif
            default_RAND_meth = RAND_OpenSSL();
    }
    return default_RAND_meth;
}

#ifndef OPENSSL_NO_ENGINE
int RAND_set_rand_engine(ENGINE *engine)
{
    const RAND_METHOD *tmp_meth = NULL;
    if (engine) {
        if (!ENGINE_init(engine))
            return 0;
        tmp_meth = ENGINE_get_RAND(engine);
        if (!tmp_meth) {
            ENGINE_finish(engine);
            return 0;
        }
    }
    /* This function releases any prior ENGINE so call it first */
    RAND_set_rand_method(tmp_meth);
    funct_ref = engine;
    return 1;
}
#endif

void RAND_cleanup(void)
{
    const RAND_METHOD *meth = RAND_get_rand_method();
    if (meth && meth->cleanup)
        meth->cleanup();
    RAND_set_rand_method(NULL);
}

void RAND_seed(const void *buf, int num)
{
    const RAND_METHOD *meth = RAND_get_rand_method();
    if (meth && meth->seed)
        meth->seed(buf, num);
}

void RAND_add(const void *buf, int num, double entropy)
{
    const RAND_METHOD *meth = RAND_get_rand_method();
    if (meth && meth->add)
        meth->add(buf, num, entropy);
}

int RAND_bytes(unsigned char *buf, int num)
{
    const RAND_METHOD *meth = RAND_get_rand_method();
    if (meth && meth->bytes)
        return meth->bytes(buf, num);
    return (-1);
}

#ifndef OPENSSL_NO_DEPRECATED
int RAND_pseudo_bytes(unsigned char *buf, int num)
{
    const RAND_METHOD *meth = RAND_get_rand_method();
    if (meth && meth->pseudorand)
        return meth->pseudorand(buf, num);
    return (-1);
}
#endif

int RAND_status(void)
{
    const RAND_METHOD *meth = RAND_get_rand_method();
    if (meth && meth->status)
        return meth->status();
    return 0;
}