/*

 * Copyright 2022-2024 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/kdf.h>

#include <openssl/proverr.h>

#include <openssl/core_names.h>

#include "prov/providercommon.h"

#include "prov/implementations.h"

#include "prov/hmac_drbg.h"

#include "prov/provider_ctx.h"

static OSSL_FUNC_kdf_newctx_fn hmac_drbg_kdf_new;

static OSSL_FUNC_kdf_dupctx_fn hmac_drbg_kdf_dup;

static OSSL_FUNC_kdf_freectx_fn hmac_drbg_kdf_free;

static OSSL_FUNC_kdf_reset_fn hmac_drbg_kdf_reset;

static OSSL_FUNC_kdf_derive_fn hmac_drbg_kdf_derive;

static OSSL_FUNC_kdf_settable_ctx_params_fn hmac_drbg_kdf_settable_ctx_params;

static OSSL_FUNC_kdf_set_ctx_params_fn hmac_drbg_kdf_set_ctx_params;

static OSSL_FUNC_kdf_gettable_ctx_params_fn hmac_drbg_kdf_gettable_ctx_params;

static OSSL_FUNC_kdf_get_ctx_params_fn hmac_drbg_kdf_get_ctx_params;

typedef struct {

    PROV_DRBG_HMAC base;

    void *provctx;

    unsigned char *entropy, *nonce;

    size_t entropylen, noncelen;

    int init;

} KDF_HMAC_DRBG;

static void *hmac_drbg_kdf_new(void *provctx)

{

    KDF_HMAC_DRBG *ctx;

    if (!ossl_prov_is_running())

        return NULL;

    ctx = OPENSSL_zalloc(sizeof(*ctx));

    if (ctx == NULL) {

        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    ctx->provctx = provctx;

    return ctx;

}

static void hmac_drbg_kdf_reset(void *vctx)

{

    KDF_HMAC_DRBG *ctx = (KDF_HMAC_DRBG *)vctx;

    PROV_DRBG_HMAC *drbg = &ctx->base;

    void *provctx = ctx->provctx;

    EVP_MAC_CTX_free(drbg->ctx);

    ossl_prov_digest_reset(&drbg->digest);

    OPENSSL_clear_free(ctx->entropy, ctx->entropylen);

    OPENSSL_clear_free(ctx->nonce, ctx->noncelen);

    OPENSSL_cleanse(ctx, sizeof(*ctx));

    ctx->provctx = provctx;

}

static void hmac_drbg_kdf_free(void *vctx)

{

    KDF_HMAC_DRBG *ctx = (KDF_HMAC_DRBG *)vctx;

    if (ctx != NULL) {

        hmac_drbg_kdf_reset(ctx);

        OPENSSL_free(ctx);

    }

}

static int ossl_drbg_hmac_dup(PROV_DRBG_HMAC *dst, const PROV_DRBG_HMAC *src) {

    if (src->ctx != NULL) {

        dst->ctx = EVP_MAC_CTX_dup(src->ctx);

        if (dst->ctx == NULL)

            return 0;

    }

    if (!ossl_prov_digest_copy(&dst->digest, &src->digest))

        return 0;

    memcpy(dst->K, src->K, sizeof(dst->K));

    memcpy(dst->V, src->V, sizeof(dst->V));

    dst->blocklen = src->blocklen;

    return 1;

}

static void *hmac_drbg_kdf_dup(void *vctx)

{

    const KDF_HMAC_DRBG *src = (const KDF_HMAC_DRBG *)vctx;

    KDF_HMAC_DRBG *dst;

    dst = hmac_drbg_kdf_new(src->provctx);

    if (dst != NULL) {

        if (!ossl_drbg_hmac_dup(&dst->base, &src->base)

                || !ossl_prov_memdup(src->entropy, src->entropylen,

                                     &dst->entropy , &dst->entropylen)

                || !ossl_prov_memdup(src->nonce, src->noncelen,

                                     &dst->nonce, &dst->noncelen))

            goto err;

        dst->init = src->init;

    }

    return dst;

 err:

    hmac_drbg_kdf_free(dst);

    return NULL;

}

static int hmac_drbg_kdf_derive(void *vctx, unsigned char *out, size_t outlen,

                                const OSSL_PARAM params[])

{

    KDF_HMAC_DRBG *ctx = (KDF_HMAC_DRBG *)vctx;

    PROV_DRBG_HMAC *drbg = &ctx->base;

    if (!ossl_prov_is_running()

            || !hmac_drbg_kdf_set_ctx_params(vctx, params))

        return 0;

    if (!ctx->init) {

        if (ctx->entropy == NULL

                || ctx->entropylen == 0

                || ctx->nonce == NULL

                || ctx->noncelen == 0

                || !ossl_drbg_hmac_init(drbg, ctx->entropy, ctx->entropylen,

                                        ctx->nonce, ctx->noncelen, NULL, 0))

            return 0;

        ctx->init = 1;

    }

    return ossl_drbg_hmac_generate(drbg, out, outlen, NULL, 0);

}

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

{

    KDF_HMAC_DRBG *hmac = (KDF_HMAC_DRBG *)vctx;

    PROV_DRBG_HMAC *drbg = &hmac->base;

    const char *name;

    const EVP_MD *md;

    OSSL_PARAM *p;

    p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_MAC);

    if (p != NULL) {

        if (drbg->ctx == NULL)

            return 0;

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

        if (!OSSL_PARAM_set_utf8_string(p, name))

            return 0;

    }

    p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_DIGEST);

    if (p != NULL) {

        md = ossl_prov_digest_md(&drbg->digest);

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

            return 0;

    }

    return 1;

}

static const OSSL_PARAM *hmac_drbg_kdf_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_KDF_PARAM_MAC, NULL, 0),

        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),

        OSSL_PARAM_END

    };

    return known_gettable_ctx_params;

}

static int hmac_drbg_kdf_set_ctx_params(void *vctx,

                                        const OSSL_PARAM params[])

{

    KDF_HMAC_DRBG *hmac = (KDF_HMAC_DRBG *)vctx;

    PROV_DRBG_HMAC *drbg = &hmac->base;

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

    const EVP_MD *md;

    const OSSL_PARAM *p;

    void *ptr = NULL;

    size_t size = 0;

    int md_size;

    if (ossl_param_is_empty(params))

        return 1;

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_HMACDRBG_ENTROPY);

    if (p != NULL) {

        if (!OSSL_PARAM_get_octet_string(p, &ptr, 0, &size))

            return 0;

        OPENSSL_free(hmac->entropy);

        hmac->entropy = ptr;

        hmac->entropylen = size;

        hmac->init = 0;

        ptr = NULL;

    }

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_HMACDRBG_NONCE);

    if (p != NULL) {

        if (!OSSL_PARAM_get_octet_string(p, &ptr, 0, &size))

            return 0;

        OPENSSL_free(hmac->nonce);

        hmac->nonce = ptr;

        hmac->noncelen = size;

        hmac->init = 0;

    }

    p = OSSL_PARAM_locate_const(params, OSSL_ALG_PARAM_DIGEST);

    if (p != NULL) {

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

            return 0;

        /* Confirm digest is allowed. Allow all digests that are not XOF */

        md = ossl_prov_digest_md(&drbg->digest);

        if (md != NULL) {

            if (EVP_MD_xof(md)) {

                ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED);

                return 0;

            }

            md_size = EVP_MD_get_size(md);

            if (md_size <= 0)

                return 0;

            drbg->blocklen = (size_t)md_size;

        }

        return ossl_prov_macctx_load_from_params(&drbg->ctx, params,

                                                 "HMAC", NULL, NULL, libctx);

    }

    return 1;

}

static const OSSL_PARAM *hmac_drbg_kdf_settable_ctx_params(

    ossl_unused void *vctx, ossl_unused void *p_ctx)

{

    static const OSSL_PARAM known_settable_ctx_params[] = {

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_HMACDRBG_ENTROPY, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_HMACDRBG_NONCE, NULL, 0),

        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),

        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),

        OSSL_PARAM_END

    };

    return known_settable_ctx_params;

}

const OSSL_DISPATCH ossl_kdf_hmac_drbg_functions[] = {

    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))hmac_drbg_kdf_new },

    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))hmac_drbg_kdf_free },

    { OSSL_FUNC_KDF_DUPCTX, (void(*)(void))hmac_drbg_kdf_dup },

    { OSSL_FUNC_KDF_RESET, (void(*)(void))hmac_drbg_kdf_reset },

    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))hmac_drbg_kdf_derive },

    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,

      (void(*)(void))hmac_drbg_kdf_settable_ctx_params },

    { OSSL_FUNC_KDF_SET_CTX_PARAMS,

      (void(*)(void))hmac_drbg_kdf_set_ctx_params },

    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,

      (void(*)(void))hmac_drbg_kdf_gettable_ctx_params },

    { OSSL_FUNC_KDF_GET_CTX_PARAMS,

      (void(*)(void))hmac_drbg_kdf_get_ctx_params },

    OSSL_DISPATCH_END

};