providers/implementations/macs/kmac_prov.c

   1 /*
   2  * Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * See SP800-185 "Appendix A - KMAC, .... in Terms of Keccak[c]"
  12  *
  13  * Inputs are:
  14  *    K = Key                  (len(K) < 2^2040 bits)
  15  *    X = Input
  16  *    L = Output length        (0 <= L < 2^2040 bits)
  17  *    S = Customization String Default="" (len(S) < 2^2040 bits)
  18  *
  19  * KMAC128(K, X, L, S)
  20  * {
  21  *     newX = bytepad(encode_string(K), 168) ||  X || right_encode(L).
  22  *     T = bytepad(encode_string("KMAC") || encode_string(S), 168).
  23  *     return KECCAK[256](T || newX || 00, L).
  24  * }
  25  *
  26  * KMAC256(K, X, L, S)
  27  * {
  28  *     newX = bytepad(encode_string(K), 136) ||  X || right_encode(L).
  29  *     T = bytepad(encode_string("KMAC") || encode_string(S), 136).
  30  *     return KECCAK[512](T || newX || 00, L).
  31  * }
  32  *
  33  * KMAC128XOF(K, X, L, S)
  34  * {
  35  *     newX = bytepad(encode_string(K), 168) ||  X || right_encode(0).
  36  *     T = bytepad(encode_string("KMAC") || encode_string(S), 168).
  37  *     return KECCAK[256](T || newX || 00, L).
  38  * }
  39  *
  40  * KMAC256XOF(K, X, L, S)
  41  * {
  42  *     newX = bytepad(encode_string(K), 136) ||  X || right_encode(0).
  43  *     T = bytepad(encode_string("KMAC") || encode_string(S), 136).
  44  *     return KECCAK[512](T || newX || 00, L).
  45  * }
  46  *
  47  */
  48
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <openssl/core_dispatch.h>
  52 #include <openssl/core_names.h>
  53 #include <openssl/params.h>
  54 #include <openssl/evp.h>
  55 #include <openssl/err.h>
  56 #include <openssl/proverr.h>
  57
  58 #include "prov/implementations.h"
  59 #include "prov/provider_ctx.h"
  60 #include "prov/provider_util.h"
  61 #include "prov/providercommon.h"
  62 #include "internal/cryptlib.h" /* ossl_assert */
  63
  64 /*
  65  * Forward declaration of everything implemented here.  This is not strictly
  66  * necessary for the compiler, but provides an assurance that the signatures
  67  * of the functions in the dispatch table are correct.
  68  */
  69 static OSSL_FUNC_mac_newctx_fn kmac128_new;
  70 static OSSL_FUNC_mac_newctx_fn kmac256_new;
  71 static OSSL_FUNC_mac_dupctx_fn kmac_dup;
  72 static OSSL_FUNC_mac_freectx_fn kmac_free;
  73 static OSSL_FUNC_mac_gettable_ctx_params_fn kmac_gettable_ctx_params;
  74 static OSSL_FUNC_mac_get_ctx_params_fn kmac_get_ctx_params;
  75 static OSSL_FUNC_mac_settable_ctx_params_fn kmac_settable_ctx_params;
  76 static OSSL_FUNC_mac_set_ctx_params_fn kmac_set_ctx_params;
  77 static OSSL_FUNC_mac_init_fn kmac_init;
  78 static OSSL_FUNC_mac_update_fn kmac_update;
  79 static OSSL_FUNC_mac_final_fn kmac_final;
  80
  81 #define KMAC_MAX_BLOCKSIZE ((1600 - 128 * 2) / 8) /* 168 */
  82
  83 /*
  84  * Length encoding will be  a 1 byte size + length in bits (3 bytes max)
  85  * This gives a range of 0..0XFFFFFF bits = 2097151 bytes).
  86  */
  87 #define KMAC_MAX_OUTPUT_LEN (0xFFFFFF / 8)
  88 #define KMAC_MAX_ENCODED_HEADER_LEN (1 + 3)
  89
  90 /*
  91  * Restrict the maximum length of the customisation string.  This must not
  92  * exceed 64 bits = 8k bytes.
  93  */
  94 #define KMAC_MAX_CUSTOM 256
  95
  96 /* Maximum size of encoded custom string */
  97 #define KMAC_MAX_CUSTOM_ENCODED (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_HEADER_LEN)
  98
  99 /* Maximum key size in bytes = 256 (2048 bits) */
 100 #define KMAC_MAX_KEY 256
 101 #define KMAC_MIN_KEY 4
 102
 103 /*
 104  * Maximum Encoded Key size will be padded to a multiple of the blocksize
 105  * i.e KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN = 256 + 4
 106  * Padded to a multiple of KMAC_MAX_BLOCKSIZE
 107  */
 108 #define KMAC_MAX_KEY_ENCODED (KMAC_MAX_BLOCKSIZE * 2)
 109
 110 /* Fixed value of encode_string("KMAC") */
 111 static const unsigned char kmac_string[] = {
 112     0x01, 0x20, 0x4B, 0x4D, 0x41, 0x43
 113 };
 114
 115 #define KMAC_FLAG_XOF_MODE          1
 116
 117 struct kmac_data_st {
 118     void  *provctx;
 119     EVP_MD_CTX *ctx;
 120     PROV_DIGEST digest;
 121     size_t out_len;
 122     size_t key_len;
 123     size_t custom_len;
 124     /* If xof_mode = 1 then we use right_encode(0) */
 125     int xof_mode;
 126     /* key and custom are stored in encoded form */
 127     unsigned char key[KMAC_MAX_KEY_ENCODED];
 128     unsigned char custom[KMAC_MAX_CUSTOM_ENCODED];
 129 };
 130
 131 static int encode_string(unsigned char *out, size_t out_max_len, size_t *out_len,
 132                          const unsigned char *in, size_t in_len);
 133 static int right_encode(unsigned char *out, size_t out_max_len, size_t *out_len,
 134                         size_t bits);
 135 static int bytepad(unsigned char *out, size_t *out_len,
 136                    const unsigned char *in1, size_t in1_len,
 137                    const unsigned char *in2, size_t in2_len,
 138                    size_t w);
 139 static int kmac_bytepad_encode_key(unsigned char *out, size_t out_max_len,
 140                                    size_t *out_len,
 141                                    const unsigned char *in, size_t in_len,
 142                                    size_t w);
 143
 144 static void kmac_free(void *vmacctx)
 145 {
 146     struct kmac_data_st *kctx = vmacctx;
 147
 148     if (kctx != NULL) {
 149         EVP_MD_CTX_free(kctx->ctx);
 150         ossl_prov_digest_reset(&kctx->digest);
 151         OPENSSL_cleanse(kctx->key, kctx->key_len);
 152         OPENSSL_cleanse(kctx->custom, kctx->custom_len);
 153         OPENSSL_free(kctx);
 154     }
 155 }
 156
 157 /*
 158  * We have KMAC implemented as a hash, which we can use instead of
 159  * reimplementing the EVP functionality with direct use of
 160  * keccak_mac_init() and friends.
 161  */
 162 static struct kmac_data_st *kmac_new(void *provctx)
 163 {
 164     struct kmac_data_st *kctx;
 165
 166     if (!ossl_prov_is_running())
 167         return NULL;
 168
 169     if ((kctx = OPENSSL_zalloc(sizeof(*kctx))) == NULL
 170             || (kctx->ctx = EVP_MD_CTX_new()) == NULL) {
 171         kmac_free(kctx);
 172         return NULL;
 173     }
 174     kctx->provctx = provctx;
 175     return kctx;
 176 }
 177
 178 static void *kmac_fetch_new(void *provctx, const OSSL_PARAM *params)
 179 {
 180     struct kmac_data_st *kctx = kmac_new(provctx);
 181
 182     if (kctx == NULL)
 183         return 0;
 184     if (!ossl_prov_digest_load_from_params(&kctx->digest, params,
 185                                       PROV_LIBCTX_OF(provctx))) {
 186         kmac_free(kctx);
 187         return 0;
 188     }
 189
 190     kctx->out_len = EVP_MD_get_size(ossl_prov_digest_md(&kctx->digest));
 191     return kctx;
 192 }
 193
 194 static void *kmac128_new(void *provctx)
 195 {
 196     static const OSSL_PARAM kmac128_params[] = {
 197         OSSL_PARAM_utf8_string("digest", OSSL_DIGEST_NAME_KECCAK_KMAC128,
 198                                sizeof(OSSL_DIGEST_NAME_KECCAK_KMAC128)),
 199         OSSL_PARAM_END
 200     };
 201     return kmac_fetch_new(provctx, kmac128_params);
 202 }
 203
 204 static void *kmac256_new(void *provctx)
 205 {
 206     static const OSSL_PARAM kmac256_params[] = {
 207         OSSL_PARAM_utf8_string("digest", OSSL_DIGEST_NAME_KECCAK_KMAC256,
 208                                sizeof(OSSL_DIGEST_NAME_KECCAK_KMAC256)),
 209         OSSL_PARAM_END
 210     };
 211     return kmac_fetch_new(provctx, kmac256_params);
 212 }
 213
 214 static void *kmac_dup(void *vsrc)
 215 {
 216     struct kmac_data_st *src = vsrc;
 217     struct kmac_data_st *dst;
 218
 219     if (!ossl_prov_is_running())
 220         return NULL;
 221
 222     dst = kmac_new(src->provctx);
 223     if (dst == NULL)
 224         return NULL;
 225
 226     if (!EVP_MD_CTX_copy(dst->ctx, src->ctx)
 227         || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
 228         kmac_free(dst);
 229         return NULL;
 230     }
 231
 232     dst->out_len = src->out_len;
 233     dst->key_len = src->key_len;
 234     dst->custom_len = src->custom_len;
 235     dst->xof_mode = src->xof_mode;
 236     memcpy(dst->key, src->key, src->key_len);
 237     memcpy(dst->custom, src->custom, dst->custom_len);
 238
 239     return dst;
 240 }
 241
 242 static int kmac_setkey(struct kmac_data_st *kctx, const unsigned char *key,
 243                        size_t keylen)
 244 {
 245     const EVP_MD *digest = ossl_prov_digest_md(&kctx->digest);
 246     int w = EVP_MD_get_block_size(digest);
 247
 248     if (keylen < KMAC_MIN_KEY || keylen > KMAC_MAX_KEY) {
 249         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
 250         return 0;
 251     }
 252     if (w < 0) {
 253         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST_LENGTH);
 254         return 0;
 255     }
 256     if (!kmac_bytepad_encode_key(kctx->key, sizeof(kctx->key), &kctx->key_len,
 257                                  key, keylen, (size_t)w))
 258         return 0;
 259     return 1;
 260 }
 261
 262 /*
 263  * The init() assumes that any ctrl methods are set beforehand for
 264  * md, key and custom. Setting the fields afterwards will have no
 265  * effect on the output mac.
 266  */
 267 static int kmac_init(void *vmacctx, const unsigned char *key,
 268                      size_t keylen, const OSSL_PARAM params[])
 269 {
 270     struct kmac_data_st *kctx = vmacctx;
 271     EVP_MD_CTX *ctx = kctx->ctx;
 272     unsigned char *out;
 273     size_t out_len, block_len;
 274     int res, t;
 275
 276     if (!ossl_prov_is_running() || !kmac_set_ctx_params(kctx, params))
 277         return 0;
 278
 279     if (key != NULL) {
 280         if (!kmac_setkey(kctx, key, keylen))
 281             return 0;
 282     } else if (kctx->key_len == 0) {
 283         /* Check key has been set */
 284         ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
 285         return 0;
 286     }
 287     if (!EVP_DigestInit_ex(kctx->ctx, ossl_prov_digest_md(&kctx->digest),
 288                            NULL))
 289         return 0;
 290
 291     t = EVP_MD_get_block_size(ossl_prov_digest_md(&kctx->digest));
 292     if (t < 0) {
 293         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST_LENGTH);
 294         return 0;
 295     }
 296     block_len = t;
 297
 298     /* Set default custom string if it is not already set */
 299     if (kctx->custom_len == 0) {
 300         const OSSL_PARAM cparams[] = {
 301             OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, "", 0),
 302             OSSL_PARAM_END
 303         };
 304         (void)kmac_set_ctx_params(kctx, cparams);
 305     }
 306
 307     if (!bytepad(NULL, &out_len, kmac_string, sizeof(kmac_string),
 308                  kctx->custom, kctx->custom_len, block_len)) {
 309         ERR_raise(ERR_LIB_PROV, ERR_R_INTERNAL_ERROR);
 310         return 0;
 311     }
 312     out = OPENSSL_malloc(out_len);
 313     if (out == NULL) {
 314         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 315         return 0;
 316     }
 317     res = bytepad(out, NULL, kmac_string, sizeof(kmac_string),
 318                   kctx->custom, kctx->custom_len, block_len)
 319           && EVP_DigestUpdate(ctx, out, out_len)
 320           && EVP_DigestUpdate(ctx, kctx->key, kctx->key_len);
 321     OPENSSL_free(out);
 322     return res;
 323 }
 324
 325 static int kmac_update(void *vmacctx, const unsigned char *data,
 326                        size_t datalen)
 327 {
 328     struct kmac_data_st *kctx = vmacctx;
 329
 330     return EVP_DigestUpdate(kctx->ctx, data, datalen);
 331 }
 332
 333 static int kmac_final(void *vmacctx, unsigned char *out, size_t *outl,
 334                       size_t outsize)
 335 {
 336     struct kmac_data_st *kctx = vmacctx;
 337     EVP_MD_CTX *ctx = kctx->ctx;
 338     size_t lbits, len;
 339     unsigned char encoded_outlen[KMAC_MAX_ENCODED_HEADER_LEN];
 340     int ok;
 341
 342     if (!ossl_prov_is_running())
 343         return 0;
 344
 345     /* KMAC XOF mode sets the encoded length to 0 */
 346     lbits = (kctx->xof_mode ? 0 : (kctx->out_len * 8));
 347
 348     ok = right_encode(encoded_outlen, sizeof(encoded_outlen), &len, lbits)
 349         && EVP_DigestUpdate(ctx, encoded_outlen, len)
 350         && EVP_DigestFinalXOF(ctx, out, kctx->out_len);
 351     *outl = kctx->out_len;
 352     return ok;
 353 }
 354
 355 static const OSSL_PARAM known_gettable_ctx_params[] = {
 356     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
 357     OSSL_PARAM_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
 358     OSSL_PARAM_END
 359 };
 360 static const OSSL_PARAM *kmac_gettable_ctx_params(ossl_unused void *ctx,
 361                                                   ossl_unused void *provctx)
 362 {
 363     return known_gettable_ctx_params;
 364 }
 365
 366 static int kmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
 367 {
 368     struct kmac_data_st *kctx = vmacctx;
 369     OSSL_PARAM *p;
 370     int sz;
 371
 372     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
 373             && !OSSL_PARAM_set_size_t(p, kctx->out_len))
 374         return 0;
 375
 376     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL) {
 377         sz = EVP_MD_block_size(ossl_prov_digest_md(&kctx->digest));
 378         if (!OSSL_PARAM_set_int(p, sz))
 379             return 0;
 380     }
 381
 382     return 1;
 383 }
 384
 385 static const OSSL_PARAM known_settable_ctx_params[] = {
 386     OSSL_PARAM_int(OSSL_MAC_PARAM_XOF, NULL),
 387     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
 388     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
 389     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, NULL, 0),
 390     OSSL_PARAM_END
 391 };
 392 static const OSSL_PARAM *kmac_settable_ctx_params(ossl_unused void *ctx,
 393                                                   ossl_unused void *provctx)
 394 {
 395     return known_settable_ctx_params;
 396 }
 397
 398 /*
 399  * The following params can be set any time before final():
 400  *     - "outlen" or "size":    The requested output length.
 401  *     - "xof":                 If set, this indicates that right_encoded(0)
 402  *                              is part of the digested data, otherwise it
 403  *                              uses right_encoded(requested output length).
 404  *
 405  * All other params should be set before init().
 406  */
 407 static int kmac_set_ctx_params(void *vmacctx, const OSSL_PARAM *params)
 408 {
 409     struct kmac_data_st *kctx = vmacctx;
 410     const OSSL_PARAM *p;
 411
 412     if (params == NULL)
 413         return 1;
 414
 415     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_XOF)) != NULL
 416         && !OSSL_PARAM_get_int(p, &kctx->xof_mode))
 417         return 0;
 418     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_SIZE)) != NULL) {
 419         size_t sz = 0;
 420
 421         if (!OSSL_PARAM_get_size_t(p, &sz))
 422             return 0;
 423         if (sz > KMAC_MAX_OUTPUT_LEN) {
 424             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_OUTPUT_LENGTH);
 425             return 0;
 426         }
 427         kctx->out_len = sz;
 428     }
 429     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL
 430             && !kmac_setkey(kctx, p->data, p->data_size))
 431         return 0;
 432     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_CUSTOM))
 433         != NULL) {
 434         if (p->data_size > KMAC_MAX_CUSTOM) {
 435             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CUSTOM_LENGTH);
 436             return 0;
 437         }
 438         if (!encode_string(kctx->custom, sizeof(kctx->custom), &kctx->custom_len,
 439                            p->data, p->data_size))
 440             return 0;
 441     }
 442     return 1;
 443 }
 444
 445 /* Encoding/Padding Methods. */
 446
 447 /* Returns the number of bytes required to store 'bits' into a byte array */
 448 static unsigned int get_encode_size(size_t bits)
 449 {
 450     unsigned int cnt = 0, sz = sizeof(size_t);
 451
 452     while (bits && (cnt < sz)) {
 453         ++cnt;
 454         bits >>= 8;
 455     }
 456     /* If bits is zero 1 byte is required */
 457     if (cnt == 0)
 458         cnt = 1;
 459     return cnt;
 460 }
 461
 462 /*
 463  * Convert an integer into bytes . The number of bytes is appended
 464  * to the end of the buffer. Returns an array of bytes 'out' of size
 465  * *out_len.
 466  *
 467  * e.g if bits = 32, out[2] = { 0x20, 0x01 }
 468  */
 469 static int right_encode(unsigned char *out, size_t out_max_len, size_t *out_len,
 470                         size_t bits)
 471 {
 472     unsigned int len = get_encode_size(bits);
 473     int i;
 474
 475     if (len >= out_max_len) {
 476         ERR_raise(ERR_LIB_PROV, PROV_R_LENGTH_TOO_LARGE);
 477         return 0;
 478     }
 479
 480     /* MSB's are at the start of the bytes array */
 481     for (i = len - 1; i >= 0; --i) {
 482         out[i] = (unsigned char)(bits & 0xFF);
 483         bits >>= 8;
 484     }
 485     /* Tack the length onto the end */
 486     out[len] = (unsigned char)len;
 487
 488     /* The Returned length includes the tacked on byte */
 489     *out_len = len + 1;
 490     return 1;
 491 }
 492
 493 /*
 494  * Encodes a string with a left encoded length added. Note that the
 495  * in_len is converted to bits (*8).
 496  *
 497  * e.g- in="KMAC" gives out[6] = { 0x01, 0x20, 0x4B, 0x4D, 0x41, 0x43 }
 498  *                                 len   bits    K     M     A     C
 499  */
 500 static int encode_string(unsigned char *out, size_t out_max_len, size_t *out_len,
 501                          const unsigned char *in, size_t in_len)
 502 {
 503     if (in == NULL) {
 504         *out_len = 0;
 505     } else {
 506         size_t i, bits, len, sz;
 507
 508         bits = 8 * in_len;
 509         len = get_encode_size(bits);
 510         sz = 1 + len + in_len;
 511
 512         if (sz > out_max_len) {
 513             ERR_raise(ERR_LIB_PROV, PROV_R_LENGTH_TOO_LARGE);
 514             return 0;
 515         }
 516
 517         out[0] = (unsigned char)len;
 518         for (i = len; i > 0; --i) {
 519             out[i] = (bits & 0xFF);
 520             bits >>= 8;
 521         }
 522         memcpy(out + len + 1, in, in_len);
 523         *out_len = sz;
 524     }
 525     return 1;
 526 }
 527
 528 /*
 529  * Returns a zero padded encoding of the inputs in1 and an optional
 530  * in2 (can be NULL). The padded output must be a multiple of the blocksize 'w'.
 531  * The value of w is in bytes (< 256).
 532  *
 533  * The returned output is:
 534  *    zero_padded(multiple of w, (left_encode(w) || in1 [|| in2])
 535  */
 536 static int bytepad(unsigned char *out, size_t *out_len,
 537                    const unsigned char *in1, size_t in1_len,
 538                    const unsigned char *in2, size_t in2_len, size_t w)
 539 {
 540     int len;
 541     unsigned char *p = out;
 542     int sz = w;
 543
 544     if (out == NULL) {
 545         if (out_len == NULL) {
 546             ERR_raise(ERR_LIB_PROV, ERR_R_PASSED_NULL_PARAMETER);
 547             return 0;
 548         }
 549         sz = 2 + in1_len + (in2 != NULL ? in2_len : 0);
 550         *out_len = (sz + w - 1) / w * w;
 551         return 1;
 552     }
 553
 554     if (!ossl_assert(w <= 255))
 555         return 0;
 556
 557     /* Left encoded w */
 558     *p++ = 1;
 559     *p++ = (unsigned char)w;
 560     /* || in1 */
 561     memcpy(p, in1, in1_len);
 562     p += in1_len;
 563     /* [ || in2 ] */
 564     if (in2 != NULL && in2_len > 0) {
 565         memcpy(p, in2, in2_len);
 566         p += in2_len;
 567     }
 568     /* Figure out the pad size (divisible by w) */
 569     len = p - out;
 570     sz = (len + w - 1) / w * w;
 571     /* zero pad the end of the buffer */
 572     if (sz != len)
 573         memset(p, 0, sz - len);
 574     if (out_len != NULL)
 575         *out_len = sz;
 576     return 1;
 577 }
 578
 579 /* Returns out = bytepad(encode_string(in), w) */
 580 static int kmac_bytepad_encode_key(unsigned char *out, size_t out_max_len,
 581                                    size_t *out_len,
 582                                    const unsigned char *in, size_t in_len,
 583                                    size_t w)
 584 {
 585     unsigned char tmp[KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN];
 586     size_t tmp_len;
 587
 588     if (!encode_string(tmp, sizeof(tmp), &tmp_len, in, in_len))
 589         return 0;
 590     if (!bytepad(NULL, out_len, tmp, tmp_len, NULL, 0, w))
 591         return 0;
 592     if (!ossl_assert(*out_len <= out_max_len))
 593         return 0;
 594     return bytepad(out, NULL, tmp, tmp_len, NULL, 0, w);
 595 }
 596
 597 const OSSL_DISPATCH ossl_kmac128_functions[] = {
 598     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))kmac128_new },
 599     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))kmac_dup },
 600     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))kmac_free },
 601     { OSSL_FUNC_MAC_INIT, (void (*)(void))kmac_init },
 602     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))kmac_update },
 603     { OSSL_FUNC_MAC_FINAL, (void (*)(void))kmac_final },
 604     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
 605       (void (*)(void))kmac_gettable_ctx_params },
 606     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))kmac_get_ctx_params },
 607     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
 608       (void (*)(void))kmac_settable_ctx_params },
 609     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))kmac_set_ctx_params },
 610     { 0, NULL }
 611 };
 612
 613 const OSSL_DISPATCH ossl_kmac256_functions[] = {
 614     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))kmac256_new },
 615     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))kmac_dup },
 616     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))kmac_free },
 617     { OSSL_FUNC_MAC_INIT, (void (*)(void))kmac_init },
 618     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))kmac_update },
 619     { OSSL_FUNC_MAC_FINAL, (void (*)(void))kmac_final },
 620     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
 621       (void (*)(void))kmac_gettable_ctx_params },
 622     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))kmac_get_ctx_params },
 623     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
 624       (void (*)(void))kmac_settable_ctx_params },
 625     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))kmac_set_ctx_params },
 626     { 0, NULL }
 627 };