providers/common/kdfs/sskdf.c

   1 /*
   2  * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
   4  *
   5  * Licensed under the Apache License 2.0 (the "License").  You may not use
   6  * this file except in compliance with the License.  You can obtain a copy
   7  * in the file LICENSE in the source distribution or at
   8  * https://www.openssl.org/source/license.html
   9  */
  10
  11 /*
  12  * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
  13  * Section 4.1.
  14  *
  15  * The Single Step KDF algorithm is given by:
  16  *
  17  * Result(0) = empty bit string (i.e., the null string).
  18  * For i = 1 to reps, do the following:
  19  *   Increment counter by 1.
  20  *   Result(i) = Result(i - 1) || H(counter || Z || FixedInfo).
  21  * DKM = LeftmostBits(Result(reps), L))
  22  *
  23  * NOTES:
  24  *   Z is a shared secret required to produce the derived key material.
  25  *   counter is a 4 byte buffer.
  26  *   FixedInfo is a bit string containing context specific data.
  27  *   DKM is the output derived key material.
  28  *   L is the required size of the DKM.
  29  *   reps = [L / H_outputBits]
  30  *   H(x) is the auxiliary function that can be either a hash, HMAC or KMAC.
  31  *   H_outputBits is the length of the output of the auxiliary function H(x).
  32  *
  33  * Currently there is not a comprehensive list of test vectors for this
  34  * algorithm, especially for H(x) = HMAC and H(x) = KMAC.
  35  * Test vectors for H(x) = Hash are indirectly used by CAVS KAS tests.
  36  */
  37 #include <stdlib.h>
  38 #include <stdarg.h>
  39 #include <string.h>
  40 #include <openssl/hmac.h>
  41 #include <openssl/evp.h>
  42 #include <openssl/kdf.h>
  43 #include <openssl/core_names.h>
  44 #include <openssl/params.h>
  45 #include "internal/cryptlib.h"
  46 #include "internal/numbers.h"
  47 #include "internal/evp_int.h"
  48 #include "internal/provider_ctx.h"
  49 #include "internal/providercommonerr.h"
  50 #include "internal/provider_algs.h"
  51 #include "internal/provider_util.h"
  52
  53 typedef struct {
  54     void *provctx;
  55     EVP_MAC *mac;       /* H(x) = HMAC_hash OR H(x) = KMAC */
  56     PROV_DIGEST digest;
  57     unsigned char *secret;
  58     size_t secret_len;
  59     unsigned char *info;
  60     size_t info_len;
  61     unsigned char *salt;
  62     size_t salt_len;
  63     size_t out_len; /* optional KMAC parameter */
  64 } KDF_SSKDF;
  65
  66 #define SSKDF_MAX_INLEN (1<<30)
  67 #define SSKDF_KMAC128_DEFAULT_SALT_SIZE (168 - 4)
  68 #define SSKDF_KMAC256_DEFAULT_SALT_SIZE (136 - 4)
  69
  70 /* KMAC uses a Customisation string of 'KDF' */
  71 static const unsigned char kmac_custom_str[] = { 0x4B, 0x44, 0x46 };
  72
  73 static OSSL_OP_kdf_newctx_fn sskdf_new;
  74 static OSSL_OP_kdf_freectx_fn sskdf_free;
  75 static OSSL_OP_kdf_reset_fn sskdf_reset;
  76 static OSSL_OP_kdf_derive_fn sskdf_derive;
  77 static OSSL_OP_kdf_derive_fn x963kdf_derive;
  78 static OSSL_OP_kdf_settable_ctx_params_fn sskdf_settable_ctx_params;
  79 static OSSL_OP_kdf_set_ctx_params_fn sskdf_set_ctx_params;
  80 static OSSL_OP_kdf_gettable_ctx_params_fn sskdf_gettable_ctx_params;
  81 static OSSL_OP_kdf_get_ctx_params_fn sskdf_get_ctx_params;
  82
  83 /*
  84  * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
  85  * Section 4. One-Step Key Derivation using H(x) = hash(x)
  86  * Note: X9.63 also uses this code with the only difference being that the
  87  * counter is appended to the secret 'z'.
  88  * i.e.
  89  *   result[i] = Hash(counter || z || info) for One Step OR
  90  *   result[i] = Hash(z || counter || info) for X9.63.
  91  */
  92 static int SSKDF_hash_kdm(const EVP_MD *kdf_md,
  93                           const unsigned char *z, size_t z_len,
  94                           const unsigned char *info, size_t info_len,
  95                           unsigned int append_ctr,
  96                           unsigned char *derived_key, size_t derived_key_len)
  97 {
  98     int ret = 0, hlen;
  99     size_t counter, out_len, len = derived_key_len;
 100     unsigned char c[4];
 101     unsigned char mac[EVP_MAX_MD_SIZE];
 102     unsigned char *out = derived_key;
 103     EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
 104
 105     if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
 106             || derived_key_len > SSKDF_MAX_INLEN
 107             || derived_key_len == 0)
 108         return 0;
 109
 110     hlen = EVP_MD_size(kdf_md);
 111     if (hlen <= 0)
 112         return 0;
 113     out_len = (size_t)hlen;
 114
 115     ctx = EVP_MD_CTX_create();
 116     ctx_init = EVP_MD_CTX_create();
 117     if (ctx == NULL || ctx_init == NULL)
 118         goto end;
 119
 120     if (!EVP_DigestInit(ctx_init, kdf_md))
 121         goto end;
 122
 123     for (counter = 1;; counter++) {
 124         c[0] = (unsigned char)((counter >> 24) & 0xff);
 125         c[1] = (unsigned char)((counter >> 16) & 0xff);
 126         c[2] = (unsigned char)((counter >> 8) & 0xff);
 127         c[3] = (unsigned char)(counter & 0xff);
 128
 129         if (!(EVP_MD_CTX_copy_ex(ctx, ctx_init)
 130                 && (append_ctr || EVP_DigestUpdate(ctx, c, sizeof(c)))
 131                 && EVP_DigestUpdate(ctx, z, z_len)
 132                 && (!append_ctr || EVP_DigestUpdate(ctx, c, sizeof(c)))
 133                 && EVP_DigestUpdate(ctx, info, info_len)))
 134             goto end;
 135         if (len >= out_len) {
 136             if (!EVP_DigestFinal_ex(ctx, out, NULL))
 137                 goto end;
 138             out += out_len;
 139             len -= out_len;
 140             if (len == 0)
 141                 break;
 142         } else {
 143             if (!EVP_DigestFinal_ex(ctx, mac, NULL))
 144                 goto end;
 145             memcpy(out, mac, len);
 146             break;
 147         }
 148     }
 149     ret = 1;
 150 end:
 151     EVP_MD_CTX_destroy(ctx);
 152     EVP_MD_CTX_destroy(ctx_init);
 153     OPENSSL_cleanse(mac, sizeof(mac));
 154     return ret;
 155 }
 156
 157 static int kmac_init(EVP_MAC_CTX *ctx, const unsigned char *custom,
 158                      size_t custom_len, size_t kmac_out_len,
 159                      size_t derived_key_len, unsigned char **out)
 160 {
 161     OSSL_PARAM params[2];
 162
 163     /* Only KMAC has custom data - so return if not KMAC */
 164     if (custom == NULL)
 165         return 1;
 166
 167     params[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_CUSTOM,
 168                                                   (void *)custom, custom_len);
 169     params[1] = OSSL_PARAM_construct_end();
 170
 171     if (!EVP_MAC_CTX_set_params(ctx, params))
 172         return 0;
 173
 174     /* By default only do one iteration if kmac_out_len is not specified */
 175     if (kmac_out_len == 0)
 176         kmac_out_len = derived_key_len;
 177     /* otherwise check the size is valid */
 178     else if (!(kmac_out_len == derived_key_len
 179             || kmac_out_len == 20
 180             || kmac_out_len == 28
 181             || kmac_out_len == 32
 182             || kmac_out_len == 48
 183             || kmac_out_len == 64))
 184         return 0;
 185
 186     params[0] = OSSL_PARAM_construct_size_t(OSSL_MAC_PARAM_SIZE,
 187                                             &kmac_out_len);
 188
 189     if (EVP_MAC_CTX_set_params(ctx, params) <= 0)
 190         return 0;
 191
 192     /*
 193      * For kmac the output buffer can be larger than EVP_MAX_MD_SIZE: so
 194      * alloc a buffer for this case.
 195      */
 196     if (kmac_out_len > EVP_MAX_MD_SIZE) {
 197         *out = OPENSSL_zalloc(kmac_out_len);
 198         if (*out == NULL)
 199             return 0;
 200     }
 201     return 1;
 202 }
 203
 204 /*
 205  * Refer to https://csrc.nist.gov/publications/detail/sp/800-56c/rev-1/final
 206  * Section 4. One-Step Key Derivation using MAC: i.e either
 207  *     H(x) = HMAC-hash(salt, x) OR
 208  *     H(x) = KMAC#(salt, x, outbits, CustomString='KDF')
 209  */
 210 static int SSKDF_mac_kdm(EVP_MAC *kdf_mac, const EVP_MD *hmac_md,
 211                          const unsigned char *kmac_custom,
 212                          size_t kmac_custom_len, size_t kmac_out_len,
 213                          const unsigned char *salt, size_t salt_len,
 214                          const unsigned char *z, size_t z_len,
 215                          const unsigned char *info, size_t info_len,
 216                          unsigned char *derived_key, size_t derived_key_len)
 217 {
 218     int ret = 0;
 219     size_t counter, out_len, len;
 220     unsigned char c[4];
 221     unsigned char mac_buf[EVP_MAX_MD_SIZE];
 222     unsigned char *out = derived_key;
 223     EVP_MAC_CTX *ctx = NULL, *ctx_init = NULL;
 224     unsigned char *mac = mac_buf, *kmac_buffer = NULL;
 225     OSSL_PARAM params[3];
 226     size_t params_n = 0;
 227
 228     if (z_len > SSKDF_MAX_INLEN || info_len > SSKDF_MAX_INLEN
 229             || derived_key_len > SSKDF_MAX_INLEN
 230             || derived_key_len == 0)
 231         return 0;
 232
 233     ctx_init = EVP_MAC_CTX_new(kdf_mac);
 234     if (ctx_init == NULL)
 235         goto end;
 236
 237     if (hmac_md != NULL) {
 238         const char *mdname = EVP_MD_name(hmac_md);
 239         params[params_n++] =
 240             OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST,
 241                                              (char *)mdname, 0);
 242     }
 243     params[params_n++] =
 244         OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY, (void *)salt,
 245                                           salt_len);
 246     params[params_n] = OSSL_PARAM_construct_end();
 247
 248     if (!EVP_MAC_CTX_set_params(ctx_init, params))
 249         goto end;
 250
 251     if (!kmac_init(ctx_init, kmac_custom, kmac_custom_len, kmac_out_len,
 252                    derived_key_len, &kmac_buffer))
 253         goto end;
 254     if (kmac_buffer != NULL)
 255         mac = kmac_buffer;
 256
 257     if (!EVP_MAC_init(ctx_init))
 258         goto end;
 259
 260     out_len = EVP_MAC_size(ctx_init); /* output size */
 261     if (out_len <= 0)
 262         goto end;
 263     len = derived_key_len;
 264
 265     for (counter = 1;; counter++) {
 266         c[0] = (unsigned char)((counter >> 24) & 0xff);
 267         c[1] = (unsigned char)((counter >> 16) & 0xff);
 268         c[2] = (unsigned char)((counter >> 8) & 0xff);
 269         c[3] = (unsigned char)(counter & 0xff);
 270
 271         ctx = EVP_MAC_CTX_dup(ctx_init);
 272         if (!(ctx != NULL
 273                 && EVP_MAC_update(ctx, c, sizeof(c))
 274                 && EVP_MAC_update(ctx, z, z_len)
 275                 && EVP_MAC_update(ctx, info, info_len)))
 276             goto end;
 277         if (len >= out_len) {
 278             if (!EVP_MAC_final(ctx, out, NULL, len))
 279                 goto end;
 280             out += out_len;
 281             len -= out_len;
 282             if (len == 0)
 283                 break;
 284         } else {
 285             if (!EVP_MAC_final(ctx, mac, NULL, len))
 286                 goto end;
 287             memcpy(out, mac, len);
 288             break;
 289         }
 290         EVP_MAC_CTX_free(ctx);
 291         ctx = NULL;
 292     }
 293     ret = 1;
 294 end:
 295     if (kmac_buffer != NULL)
 296         OPENSSL_clear_free(kmac_buffer, kmac_out_len);
 297     else
 298         OPENSSL_cleanse(mac_buf, sizeof(mac_buf));
 299
 300     EVP_MAC_CTX_free(ctx);
 301     EVP_MAC_CTX_free(ctx_init);
 302     return ret;
 303 }
 304
 305 static void *sskdf_new(void *provctx)
 306 {
 307     KDF_SSKDF *ctx;
 308
 309     if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
 310         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 311     ctx->provctx = provctx;
 312     return ctx;
 313 }
 314
 315 static void sskdf_reset(void *vctx)
 316 {
 317     KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
 318
 319     ossl_prov_digest_reset(&ctx->digest);
 320     EVP_MAC_free(ctx->mac);
 321     OPENSSL_clear_free(ctx->secret, ctx->secret_len);
 322     OPENSSL_clear_free(ctx->info, ctx->info_len);
 323     OPENSSL_clear_free(ctx->salt, ctx->salt_len);
 324     memset(ctx, 0, sizeof(*ctx));
 325 }
 326
 327 static void sskdf_free(void *vctx)
 328 {
 329     KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
 330
 331     sskdf_reset(ctx);
 332     OPENSSL_free(ctx);
 333 }
 334
 335 static int sskdf_set_buffer(unsigned char **out, size_t *out_len,
 336                             const OSSL_PARAM *p)
 337 {
 338     if (p->data == NULL || p->data_size == 0)
 339         return 1;
 340     OPENSSL_free(*out);
 341     *out = NULL;
 342     return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
 343 }
 344
 345 static size_t sskdf_size(KDF_SSKDF *ctx)
 346 {
 347     int len;
 348     const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
 349
 350     if (md == NULL) {
 351         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
 352         return 0;
 353     }
 354     len = EVP_MD_size(md);
 355     return (len <= 0) ? 0 : (size_t)len;
 356 }
 357
 358 static int sskdf_derive(void *vctx, unsigned char *key, size_t keylen)
 359 {
 360     KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
 361     const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
 362
 363     if (ctx->secret == NULL) {
 364         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
 365         return 0;
 366     }
 367
 368     if (ctx->mac != NULL) {
 369         /* H(x) = KMAC or H(x) = HMAC */
 370         int ret;
 371         const unsigned char *custom = NULL;
 372         size_t custom_len = 0;
 373         const char *macname;
 374         int default_salt_len;
 375
 376         /*
 377          * TODO(3.0) investigate the necessity to have all these controls.
 378          * Why does KMAC require a salt length that's shorter than the MD
 379          * block size?
 380          */
 381         macname = EVP_MAC_name(ctx->mac);
 382         if (strcmp(macname, OSSL_MAC_NAME_HMAC) == 0) {
 383             /* H(x) = HMAC(x, salt, hash) */
 384             if (md == NULL) {
 385                 ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
 386                 return 0;
 387             }
 388             default_salt_len = EVP_MD_block_size(md);
 389             if (default_salt_len <= 0)
 390                 return 0;
 391         } else if (strcmp(macname, OSSL_MAC_NAME_KMAC128) == 0
 392                    || strcmp(macname, OSSL_MAC_NAME_KMAC256) == 0) {
 393             /* H(x) = KMACzzz(x, salt, custom) */
 394             custom = kmac_custom_str;
 395             custom_len = sizeof(kmac_custom_str);
 396             if (strcmp(macname, OSSL_MAC_NAME_KMAC128) == 0)
 397                 default_salt_len = SSKDF_KMAC128_DEFAULT_SALT_SIZE;
 398             else
 399                 default_salt_len = SSKDF_KMAC256_DEFAULT_SALT_SIZE;
 400         } else {
 401             ERR_raise(ERR_LIB_PROV, PROV_R_UNSUPPORTED_MAC_TYPE);
 402             return 0;
 403         }
 404         /* If no salt is set then use a default_salt of zeros */
 405         if (ctx->salt == NULL || ctx->salt_len <= 0) {
 406             ctx->salt = OPENSSL_zalloc(default_salt_len);
 407             if (ctx->salt == NULL) {
 408                 ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 409                 return 0;
 410             }
 411             ctx->salt_len = default_salt_len;
 412         }
 413         ret = SSKDF_mac_kdm(ctx->mac, md,
 414                             custom, custom_len, ctx->out_len,
 415                             ctx->salt, ctx->salt_len,
 416                             ctx->secret, ctx->secret_len,
 417                             ctx->info, ctx->info_len, key, keylen);
 418         return ret;
 419     } else {
 420         /* H(x) = hash */
 421         if (md == NULL) {
 422             ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
 423             return 0;
 424         }
 425         return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
 426                               ctx->info, ctx->info_len, 0, key, keylen);
 427     }
 428 }
 429
 430 static int x963kdf_derive(void *vctx, unsigned char *key, size_t keylen)
 431 {
 432     KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
 433     const EVP_MD *md = ossl_prov_digest_md(&ctx->digest);
 434
 435     if (ctx->secret == NULL) {
 436         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SECRET);
 437         return 0;
 438     }
 439
 440     if (ctx->mac != NULL) {
 441         ERR_raise(ERR_LIB_PROV, PROV_R_NOT_SUPPORTED);
 442         return 0;
 443     } else {
 444         /* H(x) = hash */
 445         if (md == NULL) {
 446             ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MESSAGE_DIGEST);
 447             return 0;
 448         }
 449         return SSKDF_hash_kdm(md, ctx->secret, ctx->secret_len,
 450                               ctx->info, ctx->info_len, 1, key, keylen);
 451     }
 452 }
 453
 454 static int sskdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 455 {
 456     const OSSL_PARAM *p;
 457     KDF_SSKDF *ctx = vctx;
 458     OPENSSL_CTX *provctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
 459     EVP_MAC *mac;
 460     size_t sz;
 461     const char *properties = NULL;
 462
 463     if (!ossl_prov_digest_load_from_params(&ctx->digest, params, provctx))
 464         return 0;
 465
 466     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MAC)) != NULL) {
 467         EVP_MAC_free(ctx->mac);
 468         ctx->mac = NULL;
 469
 470         mac = EVP_MAC_fetch(PROV_LIBRARY_CONTEXT_OF(ctx->provctx), p->data,
 471                             properties);
 472         if (mac == NULL)
 473             return 0;
 474         EVP_MAC_free(ctx->mac);
 475         ctx->mac = mac;
 476     }
 477
 478     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SECRET)) != NULL
 479         || (p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
 480         if (!sskdf_set_buffer(&ctx->secret, &ctx->secret_len, p))
 481             return 0;
 482
 483     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO)) != NULL)
 484         if (!sskdf_set_buffer(&ctx->info, &ctx->info_len, p))
 485             return 0;
 486
 487     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
 488         if (!sskdf_set_buffer(&ctx->salt, &ctx->salt_len, p))
 489             return 0;
 490
 491     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_MAC_SIZE))
 492         != NULL) {
 493         if (!OSSL_PARAM_get_size_t(p, &sz) || sz == 0)
 494             return 0;
 495         ctx->out_len = sz;
 496     }
 497     return 1;
 498 }
 499
 500 static const OSSL_PARAM *sskdf_settable_ctx_params(void)
 501 {
 502     static const OSSL_PARAM known_settable_ctx_params[] = {
 503         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SECRET, NULL, 0),
 504         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
 505         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
 506         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
 507         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
 508         OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
 509         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 510         OSSL_PARAM_size_t(OSSL_KDF_PARAM_MAC_SIZE, NULL),
 511         OSSL_PARAM_END
 512     };
 513     return known_settable_ctx_params;
 514 }
 515
 516 static int sskdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
 517 {
 518     KDF_SSKDF *ctx = (KDF_SSKDF *)vctx;
 519     OSSL_PARAM *p;
 520
 521     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 522         return OSSL_PARAM_set_size_t(p, sskdf_size(ctx));
 523     return -2;
 524 }
 525
 526 static const OSSL_PARAM *sskdf_gettable_ctx_params(void)
 527 {
 528     static const OSSL_PARAM known_gettable_ctx_params[] = {
 529         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 530         OSSL_PARAM_END
 531     };
 532     return known_gettable_ctx_params;
 533 }
 534
 535 const OSSL_DISPATCH kdf_sskdf_functions[] = {
 536     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
 537     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
 538     { OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
 539     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))sskdf_derive },
 540     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 541       (void(*)(void))sskdf_settable_ctx_params },
 542     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
 543     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 544       (void(*)(void))sskdf_gettable_ctx_params },
 545     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },
 546     { 0, NULL }
 547 };
 548
 549 const OSSL_DISPATCH kdf_x963_kdf_functions[] = {
 550     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))sskdf_new },
 551     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))sskdf_free },
 552     { OSSL_FUNC_KDF_RESET, (void(*)(void))sskdf_reset },
 553     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))x963kdf_derive },
 554     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 555       (void(*)(void))sskdf_settable_ctx_params },
 556     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))sskdf_set_ctx_params },
 557     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 558       (void(*)(void))sskdf_gettable_ctx_params },
 559     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))sskdf_get_ctx_params },
 560     { 0, NULL }
 561 };