/* 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 <openssl/err.h>

#include <openssl/fips.h>

#include "crypto/fips.h"

#include <openssl/fips_rand.h>

#include "fips_locl.h"

#include "fips_rand_lcl.h"

/* Support framework for SP800-90 DRBGs */

int FIPS_drbg_init(DRBG_CTX *dctx, int type, unsigned int flags)

{

    int rv;

    memset(dctx, 0, sizeof(DRBG_CTX));

    dctx->status = DRBG_STATUS_UNINITIALISED;

    dctx->xflags = flags;

    dctx->type = type;

    dctx->iflags = 0;

    dctx->entropy_blocklen = 0;

    dctx->health_check_cnt = 0;

    dctx->health_check_interval = DRBG_HEALTH_INTERVAL;

    rv = fips_drbg_hash_init(dctx);

    if (rv == -2)

        rv = fips_drbg_ctr_init(dctx);

    if (rv == -2)

        rv = fips_drbg_hmac_init(dctx);

    if (rv <= 0) {

        if (rv == -2)

            FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_UNSUPPORTED_DRBG_TYPE);

        else

            FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_ERROR_INITIALISING_DRBG);

    }

    /* If not in test mode run selftests on DRBG of the same type */

    if (!(dctx->xflags & DRBG_FLAG_TEST)) {

        if (!FIPS_drbg_health_check(dctx)) {

            FIPSerr(FIPS_F_FIPS_DRBG_INIT, FIPS_R_SELFTEST_FAILURE);

            return 0;

        }

    }

    return rv;

}

DRBG_CTX *FIPS_drbg_new(int type, unsigned int flags)

{

    DRBG_CTX *dctx;

    dctx = OPENSSL_malloc(sizeof(DRBG_CTX));

    if (!dctx) {

        FIPSerr(FIPS_F_FIPS_DRBG_NEW, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    if (type == 0) {

        memset(dctx, 0, sizeof(DRBG_CTX));

        dctx->type = 0;

        dctx->status = DRBG_STATUS_UNINITIALISED;

        return dctx;

    }

    if (FIPS_drbg_init(dctx, type, flags) <= 0) {

        OPENSSL_free(dctx);

        return NULL;

    }

    return dctx;

}

void FIPS_drbg_free(DRBG_CTX *dctx)

{

    if (dctx->uninstantiate)

        dctx->uninstantiate(dctx);

    /* Don't free up default DRBG */

    if (dctx == FIPS_get_default_drbg()) {

        memset(dctx, 0, sizeof(DRBG_CTX));

        dctx->type = 0;

        dctx->status = DRBG_STATUS_UNINITIALISED;

    } else {

        OPENSSL_cleanse(&dctx->d, sizeof(dctx->d));

        OPENSSL_free(dctx);

    }

}

static size_t fips_get_entropy(DRBG_CTX *dctx, unsigned char **pout,

                               int entropy, size_t min_len, size_t max_len)

{

    unsigned char *tout, *p;

    size_t bl = dctx->entropy_blocklen, rv;

    if (!dctx->get_entropy)

        return 0;

    if (dctx->xflags & DRBG_FLAG_TEST || !bl)

        return dctx->get_entropy(dctx, pout, entropy, min_len, max_len);

    rv = dctx->get_entropy(dctx, &tout, entropy + bl,

                           min_len + bl, max_len + bl);

    if (tout == NULL)

        return 0;

    *pout = tout + bl;

    if (rv < (min_len + bl) || (rv % bl))

        return 0;

    /* Compare consecutive blocks for continuous PRNG test */

    for (p = tout; p < tout + rv - bl; p += bl) {

        if (!memcmp(p, p + bl, bl)) {

            FIPSerr(FIPS_F_FIPS_GET_ENTROPY, FIPS_R_ENTROPY_SOURCE_STUCK);

            return 0;

        }

    }

    rv -= bl;

    if (rv > max_len)

        return max_len;

    return rv;

}

static void fips_cleanup_entropy(DRBG_CTX *dctx,

                                 unsigned char *out, size_t olen)

{

    size_t bl;

    if (dctx->xflags & DRBG_FLAG_TEST)

        bl = 0;

    else

        bl = dctx->entropy_blocklen;

    /* Call cleanup with original arguments */

    dctx->cleanup_entropy(dctx, out - bl, olen + bl);

}

int FIPS_drbg_instantiate(DRBG_CTX *dctx,

                          const unsigned char *pers, size_t perslen)

{

    size_t entlen = 0, noncelen = 0;

    unsigned char *nonce = NULL, *entropy = NULL;

#if 0

    /* Put here so error script picks them up */

    FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE,

            FIPS_R_PERSONALISATION_STRING_TOO_LONG);

    FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_IN_ERROR_STATE);

    FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ALREADY_INSTANTIATED);

    FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_ENTROPY);

    FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_ERROR_RETRIEVING_NONCE);

    FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_INSTANTIATE_ERROR);

    FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, FIPS_R_DRBG_NOT_INITIALISED);

#endif

    int r = 0;

    if (perslen > dctx->max_pers) {

        r = FIPS_R_PERSONALISATION_STRING_TOO_LONG;

        goto end;

    }

    if (!dctx->instantiate) {

        r = FIPS_R_DRBG_NOT_INITIALISED;

        goto end;

    }

    if (dctx->status != DRBG_STATUS_UNINITIALISED) {

        if (dctx->status == DRBG_STATUS_ERROR)

            r = FIPS_R_IN_ERROR_STATE;

        else

            r = FIPS_R_ALREADY_INSTANTIATED;

        goto end;

    }

    dctx->status = DRBG_STATUS_ERROR;

    entlen = fips_get_entropy(dctx, &entropy, dctx->strength,

                              dctx->min_entropy, dctx->max_entropy);

    if (entlen < dctx->min_entropy || entlen > dctx->max_entropy) {

        r = FIPS_R_ERROR_RETRIEVING_ENTROPY;

        goto end;

    }

    if (dctx->max_nonce > 0 && dctx->get_nonce) {

        noncelen = dctx->get_nonce(dctx, &nonce,

                                   dctx->strength / 2,

                                   dctx->min_nonce, dctx->max_nonce);

        if (noncelen < dctx->min_nonce || noncelen > dctx->max_nonce) {

            r = FIPS_R_ERROR_RETRIEVING_NONCE;

            goto end;

        }

    }

    if (!dctx->instantiate(dctx,

                           entropy, entlen, nonce, noncelen, pers, perslen)) {

        r = FIPS_R_ERROR_INSTANTIATING_DRBG;

        goto end;

    }

    dctx->status = DRBG_STATUS_READY;

    if (!(dctx->iflags & DRBG_CUSTOM_RESEED))

        dctx->reseed_counter = 1;

 end:

    if (entropy && dctx->cleanup_entropy)

        fips_cleanup_entropy(dctx, entropy, entlen);

    if (nonce && dctx->cleanup_nonce)

        dctx->cleanup_nonce(dctx, nonce, noncelen);

    if (dctx->status == DRBG_STATUS_READY)

        return 1;

    if (r && !(dctx->iflags & DRBG_FLAG_NOERR))

        FIPSerr(FIPS_F_FIPS_DRBG_INSTANTIATE, r);

    return 0;

}

static int drbg_reseed(DRBG_CTX *dctx,

                       const unsigned char *adin, size_t adinlen, int hcheck)

{

    unsigned char *entropy = NULL;

    size_t entlen = 0;

    int r = 0;

#if 0

    FIPSerr(FIPS_F_DRBG_RESEED, FIPS_R_NOT_INSTANTIATED);

    FIPSerr(FIPS_F_DRBG_RESEED, FIPS_R_ADDITIONAL_INPUT_TOO_LONG);

#endif

    if (dctx->status != DRBG_STATUS_READY

        && dctx->status != DRBG_STATUS_RESEED) {

        if (dctx->status == DRBG_STATUS_ERROR)

            r = FIPS_R_IN_ERROR_STATE;

        else if (dctx->status == DRBG_STATUS_UNINITIALISED)

            r = FIPS_R_NOT_INSTANTIATED;

        goto end;

    }

    if (!adin)

        adinlen = 0;

    else if (adinlen > dctx->max_adin) {

        r = FIPS_R_ADDITIONAL_INPUT_TOO_LONG;

        goto end;

    }

    dctx->status = DRBG_STATUS_ERROR;

    /* Peform health check on all reseed operations if not a prediction

     * resistance request and not in test mode.

     */

    if (hcheck && !(dctx->xflags & DRBG_FLAG_TEST)) {

        if (!FIPS_drbg_health_check(dctx)) {

            r = FIPS_R_SELFTEST_FAILURE;

            goto end;

        }

    }

    entlen = fips_get_entropy(dctx, &entropy, dctx->strength,

                              dctx->min_entropy, dctx->max_entropy);

    if (entlen < dctx->min_entropy || entlen > dctx->max_entropy) {

        r = FIPS_R_ERROR_RETRIEVING_ENTROPY;

        goto end;

    }

    if (!dctx->reseed(dctx, entropy, entlen, adin, adinlen))

        goto end;

    dctx->status = DRBG_STATUS_READY;

    if (!(dctx->iflags & DRBG_CUSTOM_RESEED))

        dctx->reseed_counter = 1;

 end:

    if (entropy && dctx->cleanup_entropy)

        fips_cleanup_entropy(dctx, entropy, entlen);

    if (dctx->status == DRBG_STATUS_READY)

        return 1;

    if (r && !(dctx->iflags & DRBG_FLAG_NOERR))

        FIPSerr(FIPS_F_DRBG_RESEED, r);

    return 0;

}

int FIPS_drbg_reseed(DRBG_CTX *dctx,

                     const unsigned char *adin, size_t adinlen)

{

    int len = (int)adinlen;

    if (len < 0 || (size_t)len != adinlen) {

        FIPSerr(FIPS_F_DRBG_RESEED, FIPS_R_ADDITIONAL_INPUT_TOO_LONG);

        return 0;

    }

    RAND_seed(adin, len);

    return 1;

}

int FIPS_drbg_reseed_internal(DRBG_CTX *dctx,

                     const unsigned char *adin, size_t adinlen)

{

    return drbg_reseed(dctx, adin, adinlen, 1);

}

static int fips_drbg_check(DRBG_CTX *dctx)

{

    if (dctx->xflags & DRBG_FLAG_TEST)

        return 1;

    dctx->health_check_cnt++;

    if (dctx->health_check_cnt >= dctx->health_check_interval) {

        if (!FIPS_drbg_health_check(dctx)) {

            FIPSerr(FIPS_F_FIPS_DRBG_CHECK, FIPS_R_SELFTEST_FAILURE);

            return 0;

        }

    }

    return 1;

}

int FIPS_drbg_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,

                       int prediction_resistance,

                       const unsigned char *adin, size_t adinlen)

{

    int len = (int)outlen;

    if (len < 0 || (size_t)len != outlen) {

        FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, FIPS_R_REQUEST_TOO_LARGE_FOR_DRBG);

        return 0;

    }

    return RAND_bytes(out, len);

}

int FIPS_drbg_generate_internal(DRBG_CTX *dctx, unsigned char *out, size_t outlen,

                       int prediction_resistance,

                       const unsigned char *adin, size_t adinlen)

{

    int r = 0;

    if (FIPS_selftest_failed()) {

        FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, FIPS_R_SELFTEST_FAILED);

        return 0;

    }

    if (!fips_drbg_check(dctx))

        return 0;

    if (dctx->status != DRBG_STATUS_READY

        && dctx->status != DRBG_STATUS_RESEED) {

        if (dctx->status == DRBG_STATUS_ERROR)

            r = FIPS_R_IN_ERROR_STATE;

        else if (dctx->status == DRBG_STATUS_UNINITIALISED)

            r = FIPS_R_NOT_INSTANTIATED;

        goto end;

    }

    if (outlen > dctx->max_request) {

        r = FIPS_R_REQUEST_TOO_LARGE_FOR_DRBG;

        return 0;

    }

    if (adinlen > dctx->max_adin) {

        r = FIPS_R_ADDITIONAL_INPUT_TOO_LONG;

        goto end;

    }

    if (dctx->iflags & DRBG_CUSTOM_RESEED)

        dctx->generate(dctx, NULL, outlen, NULL, 0);

    else if (dctx->reseed_counter >= dctx->reseed_interval)

        dctx->status = DRBG_STATUS_RESEED;

    if (dctx->status == DRBG_STATUS_RESEED || prediction_resistance) {

        /* If prediction resistance request don't do health check */

        int hcheck = prediction_resistance ? 0 : 1;

        if (!drbg_reseed(dctx, adin, adinlen, hcheck)) {

            r = FIPS_R_RESEED_ERROR;

            goto end;

        }

        adin = NULL;

        adinlen = 0;

    }

    if (!dctx->generate(dctx, out, outlen, adin, adinlen)) {

        r = FIPS_R_GENERATE_ERROR;

        dctx->status = DRBG_STATUS_ERROR;

        goto end;

    }

    if (!(dctx->iflags & DRBG_CUSTOM_RESEED)) {

        if (dctx->reseed_counter >= dctx->reseed_interval)

            dctx->status = DRBG_STATUS_RESEED;

        else

            dctx->reseed_counter++;

    }

 end:

    if (r) {

        if (!(dctx->iflags & DRBG_FLAG_NOERR))

            FIPSerr(FIPS_F_FIPS_DRBG_GENERATE, r);

        return 0;

    }

    return 1;

}

int FIPS_drbg_uninstantiate(DRBG_CTX *dctx)

{

    int rv;

    if (!dctx->uninstantiate)

        rv = 1;

    else

        rv = dctx->uninstantiate(dctx);

    /* Although we'd like to cleanse here we can't because we have to

     * test the uninstantiate really zeroes the data.

     */

    memset(&dctx->d, 0, sizeof(dctx->d));

    dctx->status = DRBG_STATUS_UNINITIALISED;

    /* If method has problems uninstantiating, return error */

    return rv;

}

int FIPS_drbg_set_callbacks(DRBG_CTX *dctx,

                            size_t (*get_entropy) (DRBG_CTX *ctx,

                                                   unsigned char **pout,

                                                   int entropy,

                                                   size_t min_len,

                                                   size_t max_len),

                            void (*cleanup_entropy) (DRBG_CTX *ctx,

                                                     unsigned char *out,

                                                     size_t olen),

                            size_t entropy_blocklen,

                            size_t (*get_nonce) (DRBG_CTX *ctx,

                                                 unsigned char **pout,

                                                 int entropy, size_t min_len,

                                                 size_t max_len),

                            void (*cleanup_nonce) (DRBG_CTX *ctx,

                                                   unsigned char *out,

                                                   size_t olen))

{

    if (dctx->status != DRBG_STATUS_UNINITIALISED)

        return 0;

    dctx->entropy_blocklen = entropy_blocklen;

    dctx->get_entropy = get_entropy;

    dctx->cleanup_entropy = cleanup_entropy;

    dctx->get_nonce = get_nonce;

    dctx->cleanup_nonce = cleanup_nonce;

    return 1;

}

int FIPS_drbg_set_rand_callbacks(DRBG_CTX *dctx,

                                 size_t (*get_adin) (DRBG_CTX *ctx,

                                                     unsigned char **pout),

                                 void (*cleanup_adin) (DRBG_CTX *ctx,

                                                       unsigned char *out,

                                                       size_t olen),

                                 int (*rand_seed_cb) (DRBG_CTX *ctx,

                                                      const void *buf,

                                                      int num),

                                 int (*rand_add_cb) (DRBG_CTX *ctx,

                                                     const void *buf, int num,

                                                     double entropy))

{

    if (dctx->status != DRBG_STATUS_UNINITIALISED)

        return 0;

    dctx->get_adin = get_adin;

    dctx->cleanup_adin = cleanup_adin;

    dctx->rand_seed_cb = rand_seed_cb;

    dctx->rand_add_cb = rand_add_cb;

    return 1;

}

void *FIPS_drbg_get_app_data(DRBG_CTX *dctx)

{

    return dctx->app_data;

}

void FIPS_drbg_set_app_data(DRBG_CTX *dctx, void *app_data)

{

    dctx->app_data = app_data;

}

size_t FIPS_drbg_get_blocklength(DRBG_CTX *dctx)

{

    return dctx->blocklength;

}

int FIPS_drbg_get_strength(DRBG_CTX *dctx)

{

    return dctx->strength;

}

void FIPS_drbg_set_check_interval(DRBG_CTX *dctx, int interval)

{

    dctx->health_check_interval = interval;

}

void FIPS_drbg_set_reseed_interval(DRBG_CTX *dctx, int interval)

{

    dctx->reseed_interval = interval;

}

void FIPS_drbg_stick(int onoff)

{

    /* Just backwards compatibility API call with no effect. */

}