/* fips/rand/fips_drbg_hmac.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 <stdlib.h>

#include <string.h>

#include <openssl/crypto.h>

#include <openssl/evp.h>

#include <openssl/hmac.h>

#include <openssl/aes.h>

#include <openssl/fips.h>

#include <openssl/fips_rand.h>

#include "fips_rand_lcl.h"

static int drbg_hmac_update(DRBG_CTX *dctx,

                            const unsigned char *in1, size_t in1len,

                            const unsigned char *in2, size_t in2len,

                            const unsigned char *in3, size_t in3len)

{

    static unsigned char c0 = 0, c1 = 1;

    DRBG_HMAC_CTX *hmac = &dctx->d.hmac;

    HMAC_CTX *hctx = hmac->hctx;

    if (!HMAC_Init_ex(hctx, hmac->K, dctx->blocklength, hmac->md, NULL))

        return 0;

    if (!HMAC_Update(hctx, hmac->V, dctx->blocklength))

        return 0;

    if (!HMAC_Update(hctx, &c0, 1))

        return 0;

    if (in1len && !HMAC_Update(hctx, in1, in1len))

        return 0;

    if (in2len && !HMAC_Update(hctx, in2, in2len))

        return 0;

    if (in3len && !HMAC_Update(hctx, in3, in3len))

        return 0;

    if (!HMAC_Final(hctx, hmac->K, NULL))

        return 0;

    if (!HMAC_Init_ex(hctx, hmac->K, dctx->blocklength, hmac->md, NULL))

        return 0;

    if (!HMAC_Update(hctx, hmac->V, dctx->blocklength))

        return 0;

    if (!HMAC_Final(hctx, hmac->V, NULL))

        return 0;

    if (!in1len && !in2len && !in3len)

        return 1;

    if (!HMAC_Init_ex(hctx, hmac->K, dctx->blocklength, hmac->md, NULL))

        return 0;

    if (!HMAC_Update(hctx, hmac->V, dctx->blocklength))

        return 0;

    if (!HMAC_Update(hctx, &c1, 1))

        return 0;

    if (in1len && !HMAC_Update(hctx, in1, in1len))

        return 0;

    if (in2len && !HMAC_Update(hctx, in2, in2len))

        return 0;

    if (in3len && !HMAC_Update(hctx, in3, in3len))

        return 0;

    if (!HMAC_Final(hctx, hmac->K, NULL))

        return 0;

    if (!HMAC_Init_ex(hctx, hmac->K, dctx->blocklength, hmac->md, NULL))

        return 0;

    if (!HMAC_Update(hctx, hmac->V, dctx->blocklength))

        return 0;

    if (!HMAC_Final(hctx, hmac->V, NULL))

        return 0;

    return 1;

}

static int drbg_hmac_instantiate(DRBG_CTX *dctx,

                                 const unsigned char *ent, size_t ent_len,

                                 const unsigned char *nonce, size_t nonce_len,

                                 const unsigned char *pstr, size_t pstr_len)

{

    DRBG_HMAC_CTX *hmac = &dctx->d.hmac;

    memset(hmac->K, 0, dctx->blocklength);

    memset(hmac->V, 1, dctx->blocklength);

    if (!drbg_hmac_update(dctx,

                          ent, ent_len, nonce, nonce_len, pstr, pstr_len))

        return 0;

#ifdef HMAC_DRBG_TRACE

    fprintf(stderr, "K+V after instantiate:\n");

    hexprint(stderr, hmac->K, hmac->blocklength);

    hexprint(stderr, hmac->V, hmac->blocklength);

#endif

    return 1;

}

static int drbg_hmac_reseed(DRBG_CTX *dctx,

                            const unsigned char *ent, size_t ent_len,

                            const unsigned char *adin, size_t adin_len)

{

    if (!drbg_hmac_update(dctx, ent, ent_len, adin, adin_len, NULL, 0))

        return 0;

#ifdef HMAC_DRBG_TRACE

    {

        DRBG_HMAC_CTX *hmac = &dctx->d.hmac;

        fprintf(stderr, "K+V after reseed:\n");

        hexprint(stderr, hmac->K, hmac->blocklength);

        hexprint(stderr, hmac->V, hmac->blocklength);

    }

#endif

    return 1;

}

static int drbg_hmac_generate(DRBG_CTX *dctx,

                              unsigned char *out, size_t outlen,

                              const unsigned char *adin, size_t adin_len)

{

    DRBG_HMAC_CTX *hmac = &dctx->d.hmac;

    HMAC_CTX *hctx = hmac->hctx;

    const unsigned char *Vtmp = hmac->V;

    if (adin_len && !drbg_hmac_update(dctx, adin, adin_len, NULL, 0, NULL, 0))

        return 0;

    for (;;) {

        if (!HMAC_Init_ex(hctx, hmac->K, dctx->blocklength, hmac->md, NULL))

            return 0;

        if (!HMAC_Update(hctx, Vtmp, dctx->blocklength))

            return 0;

        if (outlen > dctx->blocklength) {

            if (!HMAC_Final(hctx, out, NULL))

                return 0;

            Vtmp = out;

        } else {

            if (!HMAC_Final(hctx, hmac->V, NULL))

                return 0;

            memcpy(out, hmac->V, outlen);

            break;

        }

        out += dctx->blocklength;

        outlen -= dctx->blocklength;

    }

    if (!drbg_hmac_update(dctx, adin, adin_len, NULL, 0, NULL, 0))

        return 0;

    return 1;

}

static int drbg_hmac_uninstantiate(DRBG_CTX *dctx)

{

    HMAC_CTX_free(dctx->d.hmac.hctx);

    OPENSSL_cleanse(&dctx->d.hmac, sizeof(DRBG_HMAC_CTX));

    return 1;

}

int fips_drbg_hmac_init(DRBG_CTX *dctx)

{

    const EVP_MD *md = NULL;

    DRBG_HMAC_CTX *hctx = &dctx->d.hmac;

    dctx->strength = 256;

    switch (dctx->type) {

    case NID_hmacWithSHA1:

        md = EVP_sha1();

        dctx->strength = 128;

        break;

    case NID_hmacWithSHA224:

        md = EVP_sha224();

        dctx->strength = 192;

        break;

    case NID_hmacWithSHA256:

        md = EVP_sha256();

        break;

    case NID_hmacWithSHA384:

        md = EVP_sha384();

        break;

    case NID_hmacWithSHA512:

        md = EVP_sha512();

        break;

    default:

        dctx->strength = 0;

        return -2;

    }

    dctx->instantiate = drbg_hmac_instantiate;

    dctx->reseed = drbg_hmac_reseed;

    dctx->generate = drbg_hmac_generate;

    dctx->uninstantiate = drbg_hmac_uninstantiate;

    hctx->hctx = HMAC_CTX_new();

    if (hctx->hctx == NULL)

        return -1;

    hctx->md = md;

    dctx->blocklength = M_EVP_MD_size(md);

    dctx->seedlen = M_EVP_MD_size(md);

    dctx->min_entropy = dctx->strength / 8;

    dctx->max_entropy = DRBG_MAX_LENGTH;

    dctx->min_nonce = dctx->min_entropy / 2;

    dctx->max_nonce = DRBG_MAX_LENGTH;

    dctx->max_pers = DRBG_MAX_LENGTH;

    dctx->max_adin = DRBG_MAX_LENGTH;

    dctx->max_request = 1 << 16;

    dctx->reseed_interval = 1 << 24;

    return 1;

}