/* fips/rand/fips_drbg_rand.c */

/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL

 * project.

 */

/* ====================================================================

 * Copyright (c) 2011 The OpenSSL Project.  All rights reserved.

 *

 * 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 above 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 acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    licensing@OpenSSL.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED 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 OpenSSL PROJECT OR

 * ITS 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.

 * ====================================================================

 */

#include <string.h>

#include <openssl/crypto.h>

#include "internal/thread_once.h"

#include <openssl/err.h>

#include <openssl/rand.h>

#include <openssl/fips.h>

#define FIPS_DRBG_generate FIPS_DRBG_generate_internal

#define FIPS_DRBG_reseed FIPS_DRBG_reseed_internal

#include <openssl/fips_rand.h>

#include "fips_rand_lcl.h"

/* Mapping of SP800-90 DRBGs to OpenSSL RAND_METHOD */

/* Since we only have one global PRNG used at any time in OpenSSL use a global

 * variable to store context.

 */

static DRBG_CTX ossl_dctx;

static CRYPTO_RWLOCK *fips_rand_lock = NULL;

static CRYPTO_ONCE fips_rand_lock_init = CRYPTO_ONCE_STATIC_INIT;

DEFINE_RUN_ONCE_STATIC(do_fips_rand_lock_init)

{

    fips_rand_lock = CRYPTO_THREAD_lock_new();

    return fips_rand_lock != NULL;

}

DRBG_CTX *FIPS_get_default_drbg(void)

{

    if (!RUN_ONCE(&fips_rand_lock_init, do_fips_rand_lock_init))

        return NULL;

    return &ossl_dctx;

}

static int fips_drbg_bytes(unsigned char *out, int count)

{

    DRBG_CTX *dctx = &ossl_dctx;

    int rv = 0;

    unsigned char *adin = NULL;

    size_t adinlen = 0;

    CRYPTO_THREAD_write_lock(fips_rand_lock);

    do {

        size_t rcnt;

        if (count > (int)dctx->max_request)

            rcnt = dctx->max_request;

        else

            rcnt = count;

        if (dctx->get_adin) {

            adinlen = dctx->get_adin(dctx, &adin);

            if (adinlen && !adin) {

                FIPSerr(FIPS_F_FIPS_DRBG_BYTES,

                        FIPS_R_ERROR_RETRIEVING_ADDITIONAL_INPUT);

                goto err;

            }

        }

        rv = FIPS_drbg_generate(dctx, out, rcnt, 0, adin, adinlen);

        if (adin) {

            if (dctx->cleanup_adin)

                dctx->cleanup_adin(dctx, adin, adinlen);

            adin = NULL;

        }

        if (!rv)

            goto err;

        out += rcnt;

        count -= rcnt;

    }

    while (count);

    rv = 1;

 err:

    CRYPTO_THREAD_unlock(fips_rand_lock);

    return rv;

}

static int fips_drbg_pseudo(unsigned char *out, int count)

{

    if (fips_drbg_bytes(out, count) <= 0)

        return -1;

    return 1;

}

static int fips_drbg_status(void)

{

    DRBG_CTX *dctx = &ossl_dctx;

    int rv;

    CRYPTO_THREAD_read_lock(fips_rand_lock);

    rv = dctx->status == DRBG_STATUS_READY ? 1 : 0;

    CRYPTO_THREAD_unlock(fips_rand_lock);

    return rv;

}

static void fips_drbg_cleanup(void)

{

    DRBG_CTX *dctx = &ossl_dctx;

    CRYPTO_THREAD_write_lock(fips_rand_lock);

    FIPS_drbg_uninstantiate(dctx);

    CRYPTO_THREAD_unlock(fips_rand_lock);

}

static int fips_drbg_seed(const void *seed, int seedlen)

{

    DRBG_CTX *dctx = &ossl_dctx;

    int ret = 1;

    CRYPTO_THREAD_write_lock(fips_rand_lock);

    if (dctx->rand_seed_cb)

        ret = dctx->rand_seed_cb(dctx, seed, seedlen);

    CRYPTO_THREAD_unlock(fips_rand_lock);

    return ret;

}

static int fips_drbg_add(const void *seed, int seedlen, double add_entropy)

{

    DRBG_CTX *dctx = &ossl_dctx;

    int ret = 1;

    CRYPTO_THREAD_write_lock(fips_rand_lock);

    if (dctx->rand_add_cb)

        ret = dctx->rand_add_cb(dctx, seed, seedlen, add_entropy);

    CRYPTO_THREAD_unlock(fips_rand_lock);

    return ret;

}

static const RAND_METHOD rand_drbg_meth = {

    fips_drbg_seed,

    fips_drbg_bytes,

    fips_drbg_cleanup,

    fips_drbg_add,

    fips_drbg_pseudo,

    fips_drbg_status

};

const RAND_METHOD *FIPS_drbg_method(void)

{

    return &rand_drbg_meth;

}