/*

 * Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved.

 * Copyright (c) 2019, Oracle and/or its affiliates.  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 "internal/e_os.h"

#include <openssl/core_names.h>

#include <openssl/core_dispatch.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#include <openssl/params.h>

#include <openssl/proverr.h>

#include "internal/packet.h"

#include "internal/der.h"

#include "internal/nelem.h"

#include "prov/provider_ctx.h"

#include "prov/providercommon.h"

#include "prov/implementations.h"

#include "prov/provider_util.h"

#include "prov/der_wrap.h"

#define X942KDF_MAX_INLEN (1 << 30)

static OSSL_FUNC_kdf_newctx_fn x942kdf_new;

static OSSL_FUNC_kdf_dupctx_fn x942kdf_dup;

static OSSL_FUNC_kdf_freectx_fn x942kdf_free;

static OSSL_FUNC_kdf_reset_fn x942kdf_reset;

static OSSL_FUNC_kdf_derive_fn x942kdf_derive;

static OSSL_FUNC_kdf_settable_ctx_params_fn x942kdf_settable_ctx_params;

static OSSL_FUNC_kdf_set_ctx_params_fn x942kdf_set_ctx_params;

static OSSL_FUNC_kdf_gettable_ctx_params_fn x942kdf_gettable_ctx_params;

static OSSL_FUNC_kdf_get_ctx_params_fn x942kdf_get_ctx_params;

typedef struct {

    void *provctx;

    PROV_DIGEST digest;

    unsigned char *secret;

    size_t secret_len;

    unsigned char *acvpinfo;

    size_t acvpinfo_len;

    unsigned char *partyuinfo, *partyvinfo, *supp_pubinfo, *supp_privinfo;

    size_t partyuinfo_len, partyvinfo_len, supp_pubinfo_len, supp_privinfo_len;

    size_t dkm_len;

    const unsigned char *cek_oid;

    size_t cek_oid_len;

    int use_keybits;

} KDF_X942;

/*

 * A table of allowed wrapping algorithms, oids and the associated output

 * lengths.

 * NOTE: RC2wrap and camellia128_wrap have been removed as there are no

 * corresponding ciphers for these operations.

 */

static const struct {

    const char *name;

    const unsigned char *oid;

    size_t oid_len;

    size_t keklen; /* size in bytes */

} kek_algs[] = {

    { "AES-128-WRAP", ossl_der_oid_id_aes128_wrap, DER_OID_SZ_id_aes128_wrap,

        16 },

    { "AES-192-WRAP", ossl_der_oid_id_aes192_wrap, DER_OID_SZ_id_aes192_wrap,

        24 },

    { "AES-256-WRAP", ossl_der_oid_id_aes256_wrap, DER_OID_SZ_id_aes256_wrap,

        32 },

#ifndef FIPS_MODULE

    { "DES3-WRAP", ossl_der_oid_id_alg_CMS3DESwrap,

        DER_OID_SZ_id_alg_CMS3DESwrap, 24 },

#endif

};

static int find_alg_id(OSSL_LIB_CTX *libctx, const char *algname,

    const char *propq, size_t *id)

{

    int ret = 1;

    size_t i;

    EVP_CIPHER *cipher;

    cipher = EVP_CIPHER_fetch(libctx, algname, propq);

    if (cipher != NULL) {

        for (i = 0; i < OSSL_NELEM(kek_algs); i++) {

            if (EVP_CIPHER_is_a(cipher, kek_algs[i].name)) {

                *id = i;

                goto end;

            }

        }

    }

    ret = 0;

    ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_CEK_ALG);

end:

    EVP_CIPHER_free(cipher);

    return ret;

}

static int DER_w_keyinfo(WPACKET *pkt,

    const unsigned char *der_oid, size_t der_oidlen,

    unsigned char **pcounter)

{

    return ossl_DER_w_begin_sequence(pkt, -1)

        /* Store the initial value of 1 into the counter */

        && ossl_DER_w_octet_string_uint32(pkt, -1, 1)

        /* Remember where we stored the counter in the buffer */

        && (pcounter == NULL

            || (*pcounter = WPACKET_get_curr(pkt)) != NULL)

        && ossl_DER_w_precompiled(pkt, -1, der_oid, der_oidlen)

        && ossl_DER_w_end_sequence(pkt, -1);

}

static int der_encode_sharedinfo(WPACKET *pkt, unsigned char *buf, size_t buflen,

    const unsigned char *der_oid, size_t der_oidlen,

    const unsigned char *acvp, size_t acvplen,

    const unsigned char *partyu, size_t partyulen,

    const unsigned char *partyv, size_t partyvlen,

    const unsigned char *supp_pub, size_t supp_publen,

    const unsigned char *supp_priv, size_t supp_privlen,

    uint32_t keylen_bits, unsigned char **pcounter)

{

    return (buf != NULL ? WPACKET_init_der(pkt, buf, buflen) : WPACKET_init_null_der(pkt))

        && ossl_DER_w_begin_sequence(pkt, -1)

        && (supp_priv == NULL

            || ossl_DER_w_octet_string(pkt, 3, supp_priv, supp_privlen))

        && (supp_pub == NULL

            || ossl_DER_w_octet_string(pkt, 2, supp_pub, supp_publen))

        && (keylen_bits == 0

            || ossl_DER_w_octet_string_uint32(pkt, 2, keylen_bits))

        && (partyv == NULL || ossl_DER_w_octet_string(pkt, 1, partyv, partyvlen))

        && (partyu == NULL || ossl_DER_w_octet_string(pkt, 0, partyu, partyulen))

        && (acvp == NULL || ossl_DER_w_precompiled(pkt, -1, acvp, acvplen))

        && DER_w_keyinfo(pkt, der_oid, der_oidlen, pcounter)

        && ossl_DER_w_end_sequence(pkt, -1)

        && WPACKET_finish(pkt);

}

/*

 * Encode the other info structure.

 *

 * The ANS X9.42-2003 standard uses OtherInfo:

 *

 *  OtherInfo ::= SEQUENCE {

 *      keyInfo KeySpecificInfo,

 *      partyUInfo [0] OCTET STRING OPTIONAL,

 *      partyVInfo [1] OCTET STRING OPTIONAL,

 *      suppPubInfo [2] OCTET STRING OPTIONAL,

 *      suppPrivInfo [3] OCTET STRING OPTIONAL

 *  }

 *

 *  KeySpecificInfo ::= SEQUENCE {

 *      algorithm OBJECT IDENTIFIER,

 *      counter OCTET STRING SIZE (4..4)

 *  }

 *

 *  RFC2631 Section 2.1.2 Contains the following definition for OtherInfo

 *

 *  OtherInfo ::= SEQUENCE {

 *      keyInfo KeySpecificInfo,

 *      partyAInfo [0] OCTET STRING OPTIONAL,

 *      suppPubInfo [2] OCTET STRING

 *  }

 *  Where suppPubInfo is the key length (in bits) (stored into 4 bytes)

 *

 * |keylen| is the length (in bytes) of the generated KEK. It is stored into

 *   suppPubInfo (in bits). It is ignored if the value is 0.

 * |cek_oid| The oid of the key wrapping algorithm.

 * |cek_oidlen| The length (in bytes) of the key wrapping algorithm oid,

 * |acvp| is the optional blob of DER data representing one or more of the

 *   OtherInfo fields related to |partyu|, |partyv|, |supp_pub| and |supp_priv|.

 *   This field should normally be NULL. If |acvp| is non NULL then |partyu|,

 *   |partyv|, |supp_pub| and |supp_priv| should all be NULL.

 * |acvp_len| is the |acvp| length (in bytes).

 * |partyu| is the optional public info contributed by the initiator.

 *   It can be NULL. (It is also used as the ukm by CMS).

 * |partyu_len| is the |partyu| length (in bytes).

 * |partyv| is the optional public info contributed by the responder.

 *   It can be NULL.

 * |partyv_len| is the |partyv| length (in bytes).

 * |supp_pub| is the optional additional, mutually-known public information.

 *   It can be NULL. |keylen| should be 0 if this is not NULL.

 * |supp_pub_len| is the |supp_pub| length (in bytes).

 * |supp_priv| is the optional additional, mutually-known private information.

 *   It can be NULL.

 * |supp_priv_len| is the |supp_priv| length (in bytes).

 * |der| is the returned encoded data. It must be freed by the caller.

 * |der_len| is the returned size of the encoded data.

 * |out_ctr| returns a pointer to the counter data which is embedded inside the

 *   encoded data. This allows the counter bytes to be updated without

 *   re-encoding.

 *

 * Returns: 1 if successfully encoded, or 0 otherwise.

 * Assumptions: |der|, |der_len| & |out_ctr| are not NULL.

 */

static int

x942_encode_otherinfo(size_t keylen,

    const unsigned char *cek_oid, size_t cek_oid_len,

    const unsigned char *acvp, size_t acvp_len,

    const unsigned char *partyu, size_t partyu_len,

    const unsigned char *partyv, size_t partyv_len,

    const unsigned char *supp_pub, size_t supp_pub_len,

    const unsigned char *supp_priv, size_t supp_priv_len,

    unsigned char **der, size_t *der_len,

    unsigned char **out_ctr)

{

    int ret = 0;

    unsigned char *pcounter = NULL, *der_buf = NULL;

    size_t der_buflen = 0;

    WPACKET pkt;

    uint32_t keylen_bits;

    /* keylenbits must fit into 4 bytes */

    if (keylen > 0xFFFFFF)

        return 0;

    keylen_bits = 8 * keylen;

    /* Calculate the size of the buffer */

    if (!der_encode_sharedinfo(&pkt, NULL, 0, cek_oid, cek_oid_len,

            acvp, acvp_len,

            partyu, partyu_len, partyv, partyv_len,

            supp_pub, supp_pub_len, supp_priv, supp_priv_len,

            keylen_bits, NULL)

        || !WPACKET_get_total_written(&pkt, &der_buflen))

        goto err;

    WPACKET_cleanup(&pkt);

    /* Alloc the buffer */

    der_buf = OPENSSL_zalloc(der_buflen);

    if (der_buf == NULL)

        goto err;

    /* Encode into the buffer */

    if (!der_encode_sharedinfo(&pkt, der_buf, der_buflen, cek_oid, cek_oid_len,

            acvp, acvp_len,

            partyu, partyu_len, partyv, partyv_len,

            supp_pub, supp_pub_len, supp_priv, supp_priv_len,

            keylen_bits, &pcounter))

        goto err;

    /*

     * Since we allocated the exact size required, the buffer should point to the

     * start of the allocated buffer at this point.

     */

    if (WPACKET_get_curr(&pkt) != der_buf)

        goto err;

    /*

     * The data for the DER encoded octet string of a 32 bit counter = 1

     * should be 04 04 00 00 00 01

     * So just check the header is correct and skip over it.

     * This counter will be incremented in the kdf update loop.

     */

    if (pcounter == NULL

        || pcounter[0] != 0x04

        || pcounter[1] != 0x04)

        goto err;

    *out_ctr = (pcounter + 2);

    *der = der_buf;

    *der_len = der_buflen;

    ret = 1;

err:

    WPACKET_cleanup(&pkt);

    return ret;

}

static int x942kdf_hash_kdm(const EVP_MD *kdf_md,

    const unsigned char *z, size_t z_len,

    const unsigned char *other, size_t other_len,

    unsigned char *ctr,

    unsigned char *derived_key, size_t derived_key_len)

{

    int ret = 0, hlen;

    size_t counter, out_len, len = derived_key_len;

    unsigned char mac[EVP_MAX_MD_SIZE];

    unsigned char *out = derived_key;

    EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;

    if (z_len > X942KDF_MAX_INLEN

        || other_len > X942KDF_MAX_INLEN

        || derived_key_len > X942KDF_MAX_INLEN

        || derived_key_len == 0) {

        ERR_raise(ERR_LIB_PROV, PROV_R_BAD_LENGTH);

        return 0;

    }

    hlen = EVP_MD_get_size(kdf_md);

    if (hlen <= 0)

        return 0;

    out_len = (size_t)hlen;

    ctx = EVP_MD_CTX_create();

    ctx_init = EVP_MD_CTX_create();

    if (ctx == NULL || ctx_init == NULL)

        goto end;

    if (!EVP_DigestInit(ctx_init, kdf_md))

        goto end;

    for (counter = 1;; counter++) {

        /* updating the ctr modifies 4 bytes in the 'other' buffer */

        ctr[0] = (unsigned char)((counter >> 24) & 0xff);

        ctr[1] = (unsigned char)((counter >> 16) & 0xff);

        ctr[2] = (unsigned char)((counter >> 8) & 0xff);

        ctr[3] = (unsigned char)(counter & 0xff);

        if (!EVP_MD_CTX_copy_ex(ctx, ctx_init)

            || !EVP_DigestUpdate(ctx, z, z_len)

            || !EVP_DigestUpdate(ctx, other, other_len))

            goto end;

        if (len >= out_len) {

            if (!EVP_DigestFinal_ex(ctx, out, NULL))

                goto end;

            out += out_len;

            len -= out_len;

            if (len == 0)

                break;

        } else {

            if (!EVP_DigestFinal_ex(ctx, mac, NULL))

                goto end;

            memcpy(out, mac, len);

            break;

        }

    }

    ret = 1;

end:

    EVP_MD_CTX_free(ctx);

    EVP_MD_CTX_free(ctx_init);

    OPENSSL_cleanse(mac, sizeof(mac));

    return ret;

}

static void *x942kdf_new(void *provctx)

{

    KDF_X942 *ctx;

    if (!ossl_prov_is_running())

        return NULL;

    if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)

        return NULL;

    ctx->provctx = provctx;

    ctx->use_keybits = 1;

    return ctx;

}

static void x942kdf_reset(void *vctx)

{

    KDF_X942 *ctx = (KDF_X942 *)vctx;

    void *provctx = ctx->provctx;

    ossl_prov_digest_reset(&ctx->digest);

    OPENSSL_clear_free(ctx->secret, ctx->secret_len);

    OPENSSL_clear_free(ctx->acvpinfo, ctx->acvpinfo_len);

    OPENSSL_clear_free(ctx->partyuinfo, ctx->partyuinfo_len);

    OPENSSL_clear_free(ctx->partyvinfo, ctx->partyvinfo_len);

    OPENSSL_clear_free(ctx->supp_pubinfo, ctx->supp_pubinfo_len);

    OPENSSL_clear_free(ctx->supp_privinfo, ctx->supp_privinfo_len);

    memset(ctx, 0, sizeof(*ctx));

    ctx->provctx = provctx;

    ctx->use_keybits = 1;

}

static void x942kdf_free(void *vctx)

{

    KDF_X942 *ctx = (KDF_X942 *)vctx;

    if (ctx != NULL) {

        x942kdf_reset(ctx);

        OPENSSL_free(ctx);

    }

}

static void *x942kdf_dup(void *vctx)

{

    const KDF_X942 *src = (const KDF_X942 *)vctx;

    KDF_X942 *dest;

    dest = x942kdf_new(src->provctx);

    if (dest != NULL) {

        if (!ossl_prov_memdup(src->secret, src->secret_len,

                &dest->secret, &dest->secret_len)

            || !ossl_prov_memdup(src->acvpinfo, src->acvpinfo_len,

                &dest->acvpinfo, &dest->acvpinfo_len)

            || !ossl_prov_memdup(src->partyuinfo, src->partyuinfo_len,

                &dest->partyuinfo, &dest->partyuinfo_len)

            || !ossl_prov_memdup(src->partyvinfo, src->partyvinfo_len,

                &dest->partyvinfo, &dest->partyvinfo_len)

            || !ossl_prov_memdup(src->supp_pubinfo, src->supp_pubinfo_len,

                &dest->supp_pubinfo,

                &dest->supp_pubinfo_len)

            || !ossl_prov_memdup(src->supp_privinfo, src->supp_privinfo_len,

                &dest->supp_privinfo,

                &dest->supp_privinfo_len)

            || !ossl_prov_digest_copy(&dest->digest, &src->digest))

            goto err;

        dest->cek_oid = src->cek_oid;

        dest->cek_oid_len = src->cek_oid_len;

        dest->dkm_len = src->dkm_len;

        dest->use_keybits = src->use_keybits;

    }

    return dest;

err:

    x942kdf_free(dest);

    return NULL;

}

static int x942kdf_set_buffer(unsigned char **out, size_t *out_len,

    const OSSL_PARAM *p)

{

    if (p->data_size == 0 || p->data == NULL)

        return 1;

    OPENSSL_free(*out);

    *out = NULL;

    return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);

}

static size_t x942kdf_size(KDF_X942 *ctx)

{

    int len;

    const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);

    if (md == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);

        return 0;

    }

    len = EVP_MD_get_size(md);

    return (len <= 0) ? 0 : (size_t)len;

}

static int x942kdf_derive(void *vctx, unsigned char *key, size_t keylen,

    const OSSL_PARAM params[])

{

    KDF_X942 *ctx = (KDF_X942 *)vctx;

    const EVP_MD *md;

    int ret = 0;

    unsigned char *ctr;

    unsigned char *der = NULL;

    size_t der_len = 0;

    if (!ossl_prov_is_running() || !x942kdf_set_ctx_params(ctx, params))

        return 0;

    /*

     * These 2 options encode to the same field so only one of them should be

     * active at once.

     */

    if (ctx->use_keybits && ctx->supp_pubinfo != NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_PUBINFO);

        return 0;

    }

    /*

     * If the blob of acvp data is used then the individual info fields that it

     * replaces should not also be defined.

     */

    if (ctx->acvpinfo != NULL

        && (ctx->partyuinfo != NULL

            || ctx->partyvinfo != NULL

            || ctx->supp_pubinfo != NULL

            || ctx->supp_privinfo != NULL)) {

        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DATA);

        return 0;

    }

    if (ctx->secret == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);

        return 0;

    }

    md = ossl_prov_digest_md(&ctx->digest);

    if (md == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);

        return 0;

    }

    if (ctx->cek_oid == NULL || ctx->cek_oid_len == 0) {

        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CEK_ALG);

        return 0;

    }

    if (ctx->partyuinfo != NULL && ctx->partyuinfo_len >= X942KDF_MAX_INLEN) {

        /*

         * Note the ukm length MUST be 512 bits if it is used.

         * For backwards compatibility the old check is being done.

         */

        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_UKM_LENGTH);

        return 0;

    }

    /* generate the otherinfo der */

    if (!x942_encode_otherinfo(ctx->use_keybits ? ctx->dkm_len : 0,

            ctx->cek_oid, ctx->cek_oid_len,

            ctx->acvpinfo, ctx->acvpinfo_len,

            ctx->partyuinfo, ctx->partyuinfo_len,

            ctx->partyvinfo, ctx->partyvinfo_len,

            ctx->supp_pubinfo, ctx->supp_pubinfo_len,

            ctx->supp_privinfo, ctx->supp_privinfo_len,

            &der, &der_len, &ctr)) {

        ERR_raise(ERR_LIB_PROV, PROV_R_BAD_ENCODING);

        return 0;

    }

    ret = x942kdf_hash_kdm(md, ctx->secret, ctx->secret_len,

        der, der_len, ctr, key, keylen);

    OPENSSL_free(der);

    return ret;

}

static int x942kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])

{

    const OSSL_PARAM *p, *pq;

    KDF_X942 *ctx = vctx;

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

    const char *propq = NULL;

    size_t id;

    if (params == NULL)

        return 1;

    if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))

        return 0;

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET);

    if (p == NULL)

        p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY);

    if (p != NULL && !x942kdf_set_buffer(&ctx->secret, &ctx->secret_len, p))

        return 0;

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_ACVPINFO);

    if (p != NULL

        && !x942kdf_set_buffer(&ctx->acvpinfo, &ctx->acvpinfo_len, p))

        return 0;

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_PARTYUINFO);

    if (p == NULL)

        p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_UKM);

    if (p != NULL

        && !x942kdf_set_buffer(&ctx->partyuinfo, &ctx->partyuinfo_len, p))

        return 0;

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_PARTYVINFO);

    if (p != NULL

        && !x942kdf_set_buffer(&ctx->partyvinfo, &ctx->partyvinfo_len, p))

        return 0;

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_USE_KEYBITS);

    if (p != NULL && !OSSL_PARAM_get_int(p, &ctx->use_keybits))

        return 0;

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_SUPP_PUBINFO);

    if (p != NULL) {

        if (!x942kdf_set_buffer(&ctx->supp_pubinfo, &ctx->supp_pubinfo_len, p))

            return 0;

        ctx->use_keybits = 0;

    }

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_X942_SUPP_PRIVINFO);

    if (p != NULL

        && !x942kdf_set_buffer(&ctx->supp_privinfo, &ctx->supp_privinfo_len, p))

        return 0;

    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CEK_ALG);

    if (p != NULL) {

        if (p->data_type != OSSL_PARAM_UTF8_STRING)

            return 0;

        pq = OSSL_PARAM_locate_const(params, OSSL_ALG_PARAM_PROPERTIES);

        /*

         * We already grab the properties during ossl_prov_digest_load_from_params()

         * so there is no need to check the validity again..

         */

        if (pq != NULL)

            propq = p->data;

        if (find_alg_id(provctx, p->data, propq, &id) == 0)

            return 0;

        ctx->cek_oid = kek_algs[id].oid;

        ctx->cek_oid_len = kek_algs[id].oid_len;

        ctx->dkm_len = kek_algs[id].keklen;

    }

    return 1;

}

static const OSSL_PARAM *x942kdf_settable_ctx_params(ossl_unused void *ctx,

    ossl_unused void *provctx)

{

    static const OSSL_PARAM known_settable_ctx_params[] = {

        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),

        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_UKM, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_ACVPINFO, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_PARTYUINFO, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_PARTYVINFO, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_SUPP_PUBINFO, NULL, 0),

        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_X942_SUPP_PRIVINFO, NULL, 0),

        OSSL_PARAM_int(OSSL_KDF_PARAM_X942_USE_KEYBITS, NULL),

        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CEK_ALG, NULL, 0),

        OSSL_PARAM_END

    };

    return known_settable_ctx_params;

}

static int x942kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])

{

    KDF_X942 *ctx = (KDF_X942 *)vctx;

    OSSL_PARAM *p;

    if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)

        return OSSL_PARAM_set_size_t(p, x942kdf_size(ctx));

    return -2;

}

static const OSSL_PARAM *x942kdf_gettable_ctx_params(ossl_unused void *ctx,

    ossl_unused void *provctx)

{

    static const OSSL_PARAM known_gettable_ctx_params[] = {

        OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),

        OSSL_PARAM_END

    };

    return known_gettable_ctx_params;

}

const OSSL_DISPATCH ossl_kdf_x942_kdf_functions[] = {

    { OSSL_FUNC_KDF_NEWCTX, (void (*)(void))x942kdf_new },

    { OSSL_FUNC_KDF_DUPCTX, (void (*)(void))x942kdf_dup },

    { OSSL_FUNC_KDF_FREECTX, (void (*)(void))x942kdf_free },

    { OSSL_FUNC_KDF_RESET, (void (*)(void))x942kdf_reset },

    { OSSL_FUNC_KDF_DERIVE, (void (*)(void))x942kdf_derive },

    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,

        (void (*)(void))x942kdf_settable_ctx_params },

    { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void (*)(void))x942kdf_set_ctx_params },

    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,

        (void (*)(void))x942kdf_gettable_ctx_params },

    { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void (*)(void))x942kdf_get_ctx_params },

    OSSL_DISPATCH_END

};