/* 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 "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>

# include "rand_lcl.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_SSLeay();

    }

    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);

}

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);

}

int RAND_status(void)

{

    const RAND_METHOD *meth = RAND_get_rand_method();

    if (meth && meth->status)

        return meth->status();

    return 0;

}

#ifdef OPENSSL_FIPS

/*

 * FIPS DRBG initialisation code. This sets up the DRBG for use by the rest

 * of OpenSSL.

 */

/*

 * Entropy gatherer: use standard OpenSSL PRNG to seed (this will gather

 * entropy internally through RAND_poll().

 */

static size_t drbg_get_entropy(DRBG_CTX *ctx, unsigned char **pout,

                               int entropy, size_t min_len, size_t max_len)

{

    /* Round up request to multiple of block size */

    min_len = ((min_len + 19) / 20) * 20;

    *pout = OPENSSL_malloc(min_len);

    if (!*pout)

        return 0;

    if (ssleay_rand_bytes(*pout, min_len, 0, 0) <= 0) {

        OPENSSL_free(*pout);

        *pout = NULL;

        return 0;

    }

    return min_len;

}

static void drbg_free_entropy(DRBG_CTX *ctx, unsigned char *out, size_t olen)

{

    if (out) {

        OPENSSL_cleanse(out, olen);

        OPENSSL_free(out);

    }

}

/*

 * Set "additional input" when generating random data. This uses the current

 * PID, a time value and a counter.

 */

static size_t drbg_get_adin(DRBG_CTX *ctx, unsigned char **pout)

{

    /* Use of static variables is OK as this happens under a lock */

    static unsigned char buf[16];

    static unsigned long counter;

    FIPS_get_timevec(buf, &counter);

    *pout = buf;

    return sizeof(buf);

}

/*

 * RAND_add() and RAND_seed() pass through to OpenSSL PRNG so it is

 * correctly seeded by RAND_poll().

 */

static int drbg_rand_add(DRBG_CTX *ctx, const void *in, int inlen,

                         double entropy)

{

    RAND_SSLeay()->add(in, inlen, entropy);

    return 1;

}

static int drbg_rand_seed(DRBG_CTX *ctx, const void *in, int inlen)

{

    RAND_SSLeay()->seed(in, inlen);

    return 1;

}

# ifndef OPENSSL_DRBG_DEFAULT_TYPE

#  define OPENSSL_DRBG_DEFAULT_TYPE       NID_aes_256_ctr

# endif

# ifndef OPENSSL_DRBG_DEFAULT_FLAGS

#  define OPENSSL_DRBG_DEFAULT_FLAGS      DRBG_FLAG_CTR_USE_DF

# endif

static int fips_drbg_type = OPENSSL_DRBG_DEFAULT_TYPE;

static int fips_drbg_flags = OPENSSL_DRBG_DEFAULT_FLAGS;

void RAND_set_fips_drbg_type(int type, int flags)

{

    fips_drbg_type = type;

    fips_drbg_flags = flags;

}

int RAND_init_fips(void)

{

    DRBG_CTX *dctx;

    size_t plen;

    unsigned char pers[32], *p;

# ifndef OPENSSL_ALLOW_DUAL_EC_DRBG

    if (fips_drbg_type >> 16) {

        RANDerr(RAND_F_RAND_INIT_FIPS, RAND_R_DUAL_EC_DRBG_DISABLED);

        return 0;

    }

# endif

    dctx = FIPS_get_default_drbg();

    if (FIPS_drbg_init(dctx, fips_drbg_type, fips_drbg_flags) <= 0) {

        RANDerr(RAND_F_RAND_INIT_FIPS, RAND_R_ERROR_INITIALISING_DRBG);

        return 0;

    }

    FIPS_drbg_set_callbacks(dctx,

                            drbg_get_entropy, drbg_free_entropy, 20,

                            drbg_get_entropy, drbg_free_entropy);

    FIPS_drbg_set_rand_callbacks(dctx, drbg_get_adin, 0,

                                 drbg_rand_seed, drbg_rand_add);

    /* Personalisation string: a string followed by date time vector */

    strcpy((char *)pers, "OpenSSL DRBG2.0");

    plen = drbg_get_adin(dctx, &p);

    memcpy(pers + 16, p, plen);

    if (FIPS_drbg_instantiate(dctx, pers, sizeof(pers)) <= 0) {

        RANDerr(RAND_F_RAND_INIT_FIPS, RAND_R_ERROR_INSTANTIATING_DRBG);

        return 0;

    }

    FIPS_rand_set_method(FIPS_drbg_method());

    return 1;

}

#endif