/*

 * Copyright 2011-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdlib.h>

#include <string.h>

#include <openssl/crypto.h>

#include <openssl/err.h>

#include <openssl/rand.h>

#include <openssl/proverr.h>

#include "internal/thread_once.h"

#include "prov/providercommon.h"

#include "prov/implementations.h"

#include "prov/provider_ctx.h"

#include "prov/hmac_drbg.h"

#include "drbg_local.h"

static OSSL_FUNC_rand_newctx_fn drbg_hmac_new_wrapper;

static OSSL_FUNC_rand_freectx_fn drbg_hmac_free;

static OSSL_FUNC_rand_instantiate_fn drbg_hmac_instantiate_wrapper;

static OSSL_FUNC_rand_uninstantiate_fn drbg_hmac_uninstantiate_wrapper;

static OSSL_FUNC_rand_generate_fn drbg_hmac_generate_wrapper;

static OSSL_FUNC_rand_reseed_fn drbg_hmac_reseed_wrapper;

static OSSL_FUNC_rand_settable_ctx_params_fn drbg_hmac_settable_ctx_params;

static OSSL_FUNC_rand_set_ctx_params_fn drbg_hmac_set_ctx_params;

static OSSL_FUNC_rand_gettable_ctx_params_fn drbg_hmac_gettable_ctx_params;

static OSSL_FUNC_rand_get_ctx_params_fn drbg_hmac_get_ctx_params;

static OSSL_FUNC_rand_verify_zeroization_fn drbg_hmac_verify_zeroization;

/*

 * Called twice by SP800-90Ar1 10.1.2.2 HMAC_DRBG_Update_Process.

 *

 * hmac is an object that holds the input/output Key and Value (K and V).

 * inbyte is 0x00 on the first call and 0x01 on the second call.

 * in1, in2, in3 are optional inputs that can be NULL.

 * in1len, in2len, in3len are the lengths of the input buffers.

 *

 * The returned K,V is:

 *   hmac->K = HMAC(hmac->K, hmac->V || inbyte || [in1] || [in2] || [in3])

 *   hmac->V = HMAC(hmac->K, hmac->V)

 *

 * Returns zero if an error occurs otherwise it returns 1.

 */

static int do_hmac(PROV_DRBG_HMAC *hmac, unsigned char inbyte,

                   const unsigned char *in1, size_t in1len,

                   const unsigned char *in2, size_t in2len,

                   const unsigned char *in3, size_t in3len)

{

    EVP_MAC_CTX *ctx = hmac->ctx;

    if (!EVP_MAC_init(ctx, hmac->K, hmac->blocklen, NULL)

            /* K = HMAC(K, V || inbyte || [in1] || [in2] || [in3]) */

            || !EVP_MAC_update(ctx, hmac->V, hmac->blocklen)

            || !EVP_MAC_update(ctx, &inbyte, 1)

            || !(in1 == NULL || in1len == 0 || EVP_MAC_update(ctx, in1, in1len))

            || !(in2 == NULL || in2len == 0 || EVP_MAC_update(ctx, in2, in2len))

            || !(in3 == NULL || in3len == 0 || EVP_MAC_update(ctx, in3, in3len))

            || !EVP_MAC_final(ctx, hmac->K, NULL, sizeof(hmac->K)))

        return 0;

   /* V = HMAC(K, V) */

    return EVP_MAC_init(ctx, hmac->K, hmac->blocklen, NULL)

           && EVP_MAC_update(ctx, hmac->V, hmac->blocklen)

           && EVP_MAC_final(ctx, hmac->V, NULL, sizeof(hmac->V));

}

/*

 * SP800-90Ar1 10.1.2.2 HMAC_DRBG_Update_Process

 *

 *

 * Updates the drbg objects Key(K) and Value(V) using the following algorithm:

 *   K,V = do_hmac(hmac, 0, in1, in2, in3)

 *   if (any input is not NULL)

 *     K,V = do_hmac(hmac, 1, in1, in2, in3)

 *

 * where in1, in2, in3 are optional input buffers that can be NULL.

 *       in1len, in2len, in3len are the lengths of the input buffers.

 *

 * Returns zero if an error occurs otherwise it returns 1.

 */

static int drbg_hmac_update(PROV_DRBG_HMAC *hmac,

                            const unsigned char *in1, size_t in1len,

                            const unsigned char *in2, size_t in2len,

                            const unsigned char *in3, size_t in3len)

{

    /* (Steps 1-2) K = HMAC(K, V||0x00||provided_data). V = HMAC(K,V) */

    if (!do_hmac(hmac, 0x00, in1, in1len, in2, in2len, in3, in3len))

        return 0;

    /* (Step 3) If provided_data == NULL then return (K,V) */

    if (in1len == 0 && in2len == 0 && in3len == 0)

        return 1;

    /* (Steps 4-5) K = HMAC(K, V||0x01||provided_data). V = HMAC(K,V) */

    return do_hmac(hmac, 0x01, in1, in1len, in2, in2len, in3, in3len);

}

/*

 * SP800-90Ar1 10.1.2.3 HMAC_DRBG_Instantiate_Process:

 *

 * This sets the drbg Key (K) to all zeros, and Value (V) to all 1's.

 * and then calls (K,V) = drbg_hmac_update() with input parameters:

 *   ent = entropy data (Can be NULL) of length ent_len.

 *   nonce = nonce data (Can be NULL) of length nonce_len.

 *   pstr = personalization data (Can be NULL) of length pstr_len.

 *

 * Returns zero if an error occurs otherwise it returns 1.

 */

int ossl_drbg_hmac_init(PROV_DRBG_HMAC *hmac,

                        const unsigned char *ent, size_t ent_len,

                        const unsigned char *nonce, size_t nonce_len,

                        const unsigned char *pstr, size_t pstr_len)

{

    if (hmac->ctx == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MAC);

        return 0;

    }

    /* (Step 2) Key = 0x00 00...00 */

    memset(hmac->K, 0x00, hmac->blocklen);

    /* (Step 3) V = 0x01 01...01 */

    memset(hmac->V, 0x01, hmac->blocklen);

    /* (Step 4) (K,V) = HMAC_DRBG_Update(entropy||nonce||pers string, K, V) */

    return drbg_hmac_update(hmac, ent, ent_len, nonce, nonce_len, pstr,

                            pstr_len);

}

static int drbg_hmac_instantiate(PROV_DRBG *drbg,

                                 const unsigned char *ent, size_t ent_len,

                                 const unsigned char *nonce, size_t nonce_len,

                                 const unsigned char *pstr, size_t pstr_len)

{

    return ossl_drbg_hmac_init((PROV_DRBG_HMAC *)drbg->data, ent, ent_len,

                               nonce, nonce_len, pstr, pstr_len);

}

static int drbg_hmac_instantiate_wrapper(void *vdrbg, unsigned int strength,

                                         int prediction_resistance,

                                         const unsigned char *pstr,

                                         size_t pstr_len,

                                         const OSSL_PARAM params[])

{

    PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;

    if (!ossl_prov_is_running() || !drbg_hmac_set_ctx_params(drbg, params))

        return 0;

    return ossl_prov_drbg_instantiate(drbg, strength, prediction_resistance,

                                      pstr, pstr_len);

}

/*

 * SP800-90Ar1 10.1.2.4 HMAC_DRBG_Reseed_Process:

 *

 * Reseeds the drbg's Key (K) and Value (V) by calling

 * (K,V) = drbg_hmac_update() with the following input parameters:

 *   ent = entropy input data (Can be NULL) of length ent_len.

 *   adin = additional input data (Can be NULL) of length adin_len.

 *

 * Returns zero if an error occurs otherwise it returns 1.

 */

static int drbg_hmac_reseed(PROV_DRBG *drbg,

                            const unsigned char *ent, size_t ent_len,

                            const unsigned char *adin, size_t adin_len)

{

    PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;

    /* (Step 2) (K,V) = HMAC_DRBG_Update(entropy||additional_input, K, V) */

    return drbg_hmac_update(hmac, ent, ent_len, adin, adin_len, NULL, 0);

}

static int drbg_hmac_reseed_wrapper(void *vdrbg, int prediction_resistance,

                                    const unsigned char *ent, size_t ent_len,

                                    const unsigned char *adin, size_t adin_len)

{

    PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;

    return ossl_prov_drbg_reseed(drbg, prediction_resistance, ent, ent_len,

                                 adin, adin_len);

}

/*

 * SP800-90Ar1 10.1.2.5 HMAC_DRBG_Generate_Process:

 *

 * Generates pseudo random bytes and updates the internal K,V for the drbg.

 * out is a buffer to fill with outlen bytes of pseudo random data.

 * adin is an additional_input string of size adin_len that may be NULL.

 *

 * Returns zero if an error occurs otherwise it returns 1.

 */

int ossl_drbg_hmac_generate(PROV_DRBG_HMAC *hmac,

                            unsigned char *out, size_t outlen,

                            const unsigned char *adin, size_t adin_len)

{

    EVP_MAC_CTX *ctx = hmac->ctx;

    const unsigned char *temp = hmac->V;

    /* (Step 2) if adin != NULL then (K,V) = HMAC_DRBG_Update(adin, K, V) */

    if (adin != NULL

            && adin_len > 0

            && !drbg_hmac_update(hmac, adin, adin_len, NULL, 0, NULL, 0))

        return 0;

    /*

     * (Steps 3-5) temp = NULL

     *             while (len(temp) < outlen) {

     *                 V = HMAC(K, V)

     *                 temp = temp || V

     *             }

     */

    for (;;) {

        if (!EVP_MAC_init(ctx, hmac->K, hmac->blocklen, NULL)

            || !EVP_MAC_update(ctx, temp, hmac->blocklen))

            return 0;

        if (outlen > hmac->blocklen) {

            if (!EVP_MAC_final(ctx, out, NULL, outlen))

                return 0;

            temp = out;

        } else {

            if (!EVP_MAC_final(ctx, hmac->V, NULL, sizeof(hmac->V)))

                return 0;

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

            break;

        }

        out += hmac->blocklen;

        outlen -= hmac->blocklen;

    }

    /* (Step 6) (K,V) = HMAC_DRBG_Update(adin, K, V) */

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

        return 0;

    return 1;

}

static int drbg_hmac_generate(PROV_DRBG *drbg,

                              unsigned char *out, size_t outlen,

                              const unsigned char *adin, size_t adin_len)

{

    return ossl_drbg_hmac_generate((PROV_DRBG_HMAC *)drbg->data, out, outlen,

                                    adin, adin_len);

}

static int drbg_hmac_generate_wrapper(void *vdrbg,

     unsigned char *out, size_t outlen, unsigned int strength,

     int prediction_resistance, const unsigned char *adin, size_t adin_len)

{

    PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;

    return ossl_prov_drbg_generate(drbg, out, outlen, strength,

                                   prediction_resistance, adin, adin_len);

}

static int drbg_hmac_uninstantiate(PROV_DRBG *drbg)

{

    PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;

    OPENSSL_cleanse(hmac->K, sizeof(hmac->K));

    OPENSSL_cleanse(hmac->V, sizeof(hmac->V));

    return ossl_prov_drbg_uninstantiate(drbg);

}

static int drbg_hmac_uninstantiate_wrapper(void *vdrbg)

{

    return drbg_hmac_uninstantiate((PROV_DRBG *)vdrbg);

}

static int drbg_hmac_verify_zeroization(void *vdrbg)

{

    PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;

    PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;

    PROV_DRBG_VERYIFY_ZEROIZATION(hmac->K);

    PROV_DRBG_VERYIFY_ZEROIZATION(hmac->V);

    return 1;

}

static int drbg_hmac_new(PROV_DRBG *drbg)

{

    PROV_DRBG_HMAC *hmac;

    hmac = OPENSSL_secure_zalloc(sizeof(*hmac));

    if (hmac == NULL)

        return 0;

    drbg->data = hmac;

    /* See SP800-57 Part1 Rev4 5.6.1 Table 3 */

    drbg->max_entropylen = DRBG_MAX_LENGTH;

    drbg->max_noncelen = DRBG_MAX_LENGTH;

    drbg->max_perslen = DRBG_MAX_LENGTH;

    drbg->max_adinlen = DRBG_MAX_LENGTH;

    /* Maximum number of bits per request = 2^19  = 2^16 bytes */

    drbg->max_request = 1 << 16;

    return 1;

}

static void *drbg_hmac_new_wrapper(void *provctx, void *parent,

                                   const OSSL_DISPATCH *parent_dispatch)

{

    return ossl_rand_drbg_new(provctx, parent, parent_dispatch, &drbg_hmac_new,

                              &drbg_hmac_instantiate, &drbg_hmac_uninstantiate,

                              &drbg_hmac_reseed, &drbg_hmac_generate);

}

static void drbg_hmac_free(void *vdrbg)

{

    PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;

    PROV_DRBG_HMAC *hmac;

    if (drbg != NULL && (hmac = (PROV_DRBG_HMAC *)drbg->data) != NULL) {

        EVP_MAC_CTX_free(hmac->ctx);

        ossl_prov_digest_reset(&hmac->digest);

        OPENSSL_secure_clear_free(hmac, sizeof(*hmac));

    }

    ossl_rand_drbg_free(drbg);

}

static int drbg_hmac_get_ctx_params(void *vdrbg, OSSL_PARAM params[])

{

    PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;

    PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)drbg->data;

    const char *name;

    const EVP_MD *md;

    OSSL_PARAM *p;

    p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_MAC);

    if (p != NULL) {

        if (hmac->ctx == NULL)

            return 0;

        name = EVP_MAC_get0_name(EVP_MAC_CTX_get0_mac(hmac->ctx));

        if (!OSSL_PARAM_set_utf8_string(p, name))

            return 0;

    }

    p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_DIGEST);

    if (p != NULL) {

        md = ossl_prov_digest_md(&hmac->digest);

        if (md == NULL || !OSSL_PARAM_set_utf8_string(p, EVP_MD_get0_name(md)))

            return 0;

    }

    return ossl_drbg_get_ctx_params(drbg, params);

}

static const OSSL_PARAM *drbg_hmac_gettable_ctx_params(ossl_unused void *vctx,

                                                       ossl_unused void *p_ctx)

{

    static const OSSL_PARAM known_gettable_ctx_params[] = {

        OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_MAC, NULL, 0),

        OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_DIGEST, NULL, 0),

        OSSL_PARAM_DRBG_GETTABLE_CTX_COMMON,

        OSSL_PARAM_END

    };

    return known_gettable_ctx_params;

}

static int drbg_hmac_set_ctx_params(void *vctx, const OSSL_PARAM params[])

{

    PROV_DRBG *ctx = (PROV_DRBG *)vctx;

    PROV_DRBG_HMAC *hmac = (PROV_DRBG_HMAC *)ctx->data;

    OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);

    const EVP_MD *md;

    if (!ossl_prov_digest_load_from_params(&hmac->digest, params, libctx))

        return 0;

    md = ossl_prov_digest_md(&hmac->digest);

    if (md != NULL && !ossl_drbg_verify_digest(libctx, md))

        return 0;   /* Error already raised for us */

    if (!ossl_prov_macctx_load_from_params(&hmac->ctx, params,

                                           NULL, NULL, NULL, libctx))

        return 0;

    if (md != NULL && hmac->ctx != NULL) {

        /* These are taken from SP 800-90 10.1 Table 2 */

        hmac->blocklen = EVP_MD_get_size(md);

        /* See SP800-57 Part1 Rev4 5.6.1 Table 3 */

        ctx->strength = 64 * (int)(hmac->blocklen >> 3);

        if (ctx->strength > 256)

            ctx->strength = 256;

        ctx->seedlen = hmac->blocklen;

        ctx->min_entropylen = ctx->strength / 8;

        ctx->min_noncelen = ctx->min_entropylen / 2;

    }

    return ossl_drbg_set_ctx_params(ctx, params);

}

static const OSSL_PARAM *drbg_hmac_settable_ctx_params(ossl_unused void *vctx,

                                                       ossl_unused void *p_ctx)

{

    static const OSSL_PARAM known_settable_ctx_params[] = {

        OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_PROPERTIES, NULL, 0),

        OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_DIGEST, NULL, 0),

        OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_MAC, NULL, 0),

        OSSL_PARAM_DRBG_SETTABLE_CTX_COMMON,

        OSSL_PARAM_END

    };

    return known_settable_ctx_params;

}

const OSSL_DISPATCH ossl_drbg_ossl_hmac_functions[] = {

    { OSSL_FUNC_RAND_NEWCTX, (void(*)(void))drbg_hmac_new_wrapper },

    { OSSL_FUNC_RAND_FREECTX, (void(*)(void))drbg_hmac_free },

    { OSSL_FUNC_RAND_INSTANTIATE,

      (void(*)(void))drbg_hmac_instantiate_wrapper },

    { OSSL_FUNC_RAND_UNINSTANTIATE,

      (void(*)(void))drbg_hmac_uninstantiate_wrapper },

    { OSSL_FUNC_RAND_GENERATE, (void(*)(void))drbg_hmac_generate_wrapper },

    { OSSL_FUNC_RAND_RESEED, (void(*)(void))drbg_hmac_reseed_wrapper },

    { OSSL_FUNC_RAND_ENABLE_LOCKING, (void(*)(void))ossl_drbg_enable_locking },

    { OSSL_FUNC_RAND_LOCK, (void(*)(void))ossl_drbg_lock },

    { OSSL_FUNC_RAND_UNLOCK, (void(*)(void))ossl_drbg_unlock },

    { OSSL_FUNC_RAND_SETTABLE_CTX_PARAMS,

      (void(*)(void))drbg_hmac_settable_ctx_params },

    { OSSL_FUNC_RAND_SET_CTX_PARAMS, (void(*)(void))drbg_hmac_set_ctx_params },

    { OSSL_FUNC_RAND_GETTABLE_CTX_PARAMS,

      (void(*)(void))drbg_hmac_gettable_ctx_params },

    { OSSL_FUNC_RAND_GET_CTX_PARAMS, (void(*)(void))drbg_hmac_get_ctx_params },

    { OSSL_FUNC_RAND_VERIFY_ZEROIZATION,

      (void(*)(void))drbg_hmac_verify_zeroization },

    { OSSL_FUNC_RAND_GET_SEED, (void(*)(void))ossl_drbg_get_seed },

    { OSSL_FUNC_RAND_CLEAR_SEED, (void(*)(void))ossl_drbg_clear_seed },

    { 0, NULL }

};