providers/implementations/macs/kmac_prov.c

   1 /*
   2  * Copyright 2018-2020 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
  57 #include "prov/providercommonerr.h"
  58 #include "prov/implementations.h"
  59 #include "prov/provider_ctx.h"
  60 #include "prov/provider_util.h"
  61 #include "prov/providercommon.h"
  62
  63 /*
  64  * Forward declaration of everything implemented here.  This is not strictly
  65  * necessary for the compiler, but provides an assurance that the signatures
  66  * of the functions in the dispatch table are correct.
  67  */
  68 static OSSL_FUNC_mac_newctx_fn kmac128_new;
  69 static OSSL_FUNC_mac_newctx_fn kmac256_new;
  70 static OSSL_FUNC_mac_dupctx_fn kmac_dup;
  71 static OSSL_FUNC_mac_freectx_fn kmac_free;
  72 static OSSL_FUNC_mac_gettable_ctx_params_fn kmac_gettable_ctx_params;
  73 static OSSL_FUNC_mac_get_ctx_params_fn kmac_get_ctx_params;
  74 static OSSL_FUNC_mac_settable_ctx_params_fn kmac_settable_ctx_params;
  75 static OSSL_FUNC_mac_set_ctx_params_fn kmac_set_ctx_params;
  76 static OSSL_FUNC_mac_size_fn kmac_size;
  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 #define KMAC_MIN_BLOCKSIZE ((1600 - 256*2) / 8) /* 136 */
  83
  84 /* Length encoding will be  a 1 byte size + length in bits (2 bytes max) */
  85 #define KMAC_MAX_ENCODED_HEADER_LEN 3
  86
  87 /*
  88  * Custom string max size is chosen such that:
  89  *   len(encoded_string(custom) + len(kmac_encoded_string) <= KMAC_MIN_BLOCKSIZE
  90  *   i.e: (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_LEN) + 6 <= 136
  91  */
  92 #define KMAC_MAX_CUSTOM 127
  93
  94 /* Maximum size of encoded custom string */
  95 #define KMAC_MAX_CUSTOM_ENCODED (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_HEADER_LEN)
  96
  97 /* Maximum key size in bytes = 2040 / 8 */
  98 #define KMAC_MAX_KEY 255
  99
 100 /*
 101  * Maximum Encoded Key size will be padded to a multiple of the blocksize
 102  * i.e KMAC_MAX_KEY + KMAC_MAX_ENCODED_LEN = 258
 103  * Padded to a multiple of KMAC_MAX_BLOCKSIZE
 104  */
 105 #define KMAC_MAX_KEY_ENCODED (KMAC_MAX_BLOCKSIZE * 2)
 106
 107 /* Fixed value of encode_string("KMAC") */
 108 static const unsigned char kmac_string[] = {
 109     0x01, 0x20, 0x4B, 0x4D, 0x41, 0x43
 110 };
 111
 112
 113 #define KMAC_FLAG_XOF_MODE          1
 114
 115 struct kmac_data_st {
 116     void  *provctx;
 117     EVP_MD_CTX *ctx;
 118     PROV_DIGEST digest;
 119     size_t out_len;
 120     int key_len;
 121     int custom_len;
 122     /* If xof_mode = 1 then we use right_encode(0) */
 123     int xof_mode;
 124     /* key and custom are stored in encoded form */
 125     unsigned char key[KMAC_MAX_KEY_ENCODED];
 126     unsigned char custom[KMAC_MAX_CUSTOM_ENCODED];
 127 };
 128
 129 static int encode_string(unsigned char *out, int *out_len,
 130                          const unsigned char *in, int in_len);
 131 static int right_encode(unsigned char *out, int *out_len, size_t bits);
 132 static int bytepad(unsigned char *out, int *out_len,
 133                    const unsigned char *in1, int in1_len,
 134                    const unsigned char *in2, int in2_len,
 135                    int w);
 136 static int kmac_bytepad_encode_key(unsigned char *out, int *out_len,
 137                                    const unsigned char *in, int in_len,
 138                                    int w);
 139
 140 static void kmac_free(void *vmacctx)
 141 {
 142     struct kmac_data_st *kctx = vmacctx;
 143
 144     if (kctx != NULL) {
 145         EVP_MD_CTX_free(kctx->ctx);
 146         ossl_prov_digest_reset(&kctx->digest);
 147         OPENSSL_cleanse(kctx->key, kctx->key_len);
 148         OPENSSL_cleanse(kctx->custom, kctx->custom_len);
 149         OPENSSL_free(kctx);
 150     }
 151 }
 152
 153 /*
 154  * We have KMAC implemented as a hash, which we can use instead of
 155  * reimplementing the EVP functionality with direct use of
 156  * keccak_mac_init() and friends.
 157  */
 158 static struct kmac_data_st *kmac_new(void *provctx)
 159 {
 160     struct kmac_data_st *kctx;
 161
 162     if (!ossl_prov_is_running())
 163         return NULL;
 164
 165     if ((kctx = OPENSSL_zalloc(sizeof(*kctx))) == NULL
 166             || (kctx->ctx = EVP_MD_CTX_new()) == NULL) {
 167         kmac_free(kctx);
 168         return NULL;
 169     }
 170     kctx->provctx = provctx;
 171     return kctx;
 172 }
 173
 174 static void *kmac_fetch_new(void *provctx, const OSSL_PARAM *params)
 175 {
 176     struct kmac_data_st *kctx = kmac_new(provctx);
 177
 178     if (kctx == NULL)
 179         return 0;
 180     if (!ossl_prov_digest_load_from_params(&kctx->digest, params,
 181                                       PROV_LIBRARY_CONTEXT_OF(provctx))) {
 182         kmac_free(kctx);
 183         return 0;
 184     }
 185
 186     kctx->out_len = EVP_MD_size(ossl_prov_digest_md(&kctx->digest));
 187     return kctx;
 188 }
 189
 190 static void *kmac128_new(void *provctx)
 191 {
 192     static const OSSL_PARAM kmac128_params[] = {
 193         OSSL_PARAM_utf8_string("digest", OSSL_DIGEST_NAME_KECCAK_KMAC128,
 194                                sizeof(OSSL_DIGEST_NAME_KECCAK_KMAC128)),
 195         OSSL_PARAM_END
 196     };
 197     return kmac_fetch_new(provctx, kmac128_params);
 198 }
 199
 200 static void *kmac256_new(void *provctx)
 201 {
 202     static const OSSL_PARAM kmac256_params[] = {
 203         OSSL_PARAM_utf8_string("digest", OSSL_DIGEST_NAME_KECCAK_KMAC256,
 204                                sizeof(OSSL_DIGEST_NAME_KECCAK_KMAC256)),
 205         OSSL_PARAM_END
 206     };
 207     return kmac_fetch_new(provctx, kmac256_params);
 208 }
 209
 210 static void *kmac_dup(void *vsrc)
 211 {
 212     struct kmac_data_st *src = vsrc;
 213     struct kmac_data_st *dst;
 214
 215     if (!ossl_prov_is_running())
 216         return NULL;
 217
 218     dst = kmac_new(src->provctx);
 219     if (dst == NULL)
 220         return NULL;
 221
 222     if (!EVP_MD_CTX_copy(dst->ctx, src->ctx)
 223         || !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
 224         kmac_free(dst);
 225         return NULL;
 226     }
 227
 228     dst->out_len = src->out_len;
 229     dst->key_len = src->key_len;
 230     dst->custom_len = src->custom_len;
 231     dst->xof_mode = src->xof_mode;
 232     memcpy(dst->key, src->key, src->key_len);
 233     memcpy(dst->custom, src->custom, dst->custom_len);
 234
 235     return dst;
 236 }
 237
 238 /*
 239  * The init() assumes that any ctrl methods are set beforehand for
 240  * md, key and custom. Setting the fields afterwards will have no
 241  * effect on the output mac.
 242  */
 243 static int kmac_init(void *vmacctx)
 244 {
 245     struct kmac_data_st *kctx = vmacctx;
 246     EVP_MD_CTX *ctx = kctx->ctx;
 247     unsigned char out[KMAC_MAX_BLOCKSIZE];
 248     int out_len, block_len;
 249
 250     if (!ossl_prov_is_running())
 251         return 0;
 252
 253     /* Check key has been set */
 254     if (kctx->key_len == 0) {
 255         EVPerr(EVP_F_KMAC_INIT, EVP_R_NO_KEY_SET);
 256         return 0;
 257     }
 258     if (!EVP_DigestInit_ex(kctx->ctx, ossl_prov_digest_md(&kctx->digest),
 259                            NULL))
 260         return 0;
 261
 262     block_len = EVP_MD_block_size(ossl_prov_digest_md(&kctx->digest));
 263     if (block_len < 0)
 264         return 0;
 265
 266     /* Set default custom string if it is not already set */
 267     if (kctx->custom_len == 0) {
 268         const OSSL_PARAM params[] = {
 269             OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, "", 0),
 270             OSSL_PARAM_END
 271         };
 272         (void)kmac_set_ctx_params(kctx, params);
 273     }
 274
 275     return bytepad(out, &out_len, kmac_string, sizeof(kmac_string),
 276                    kctx->custom, kctx->custom_len, block_len)
 277            && EVP_DigestUpdate(ctx, out, out_len)
 278            && EVP_DigestUpdate(ctx, kctx->key, kctx->key_len);
 279 }
 280
 281 static size_t kmac_size(void *vmacctx)
 282 {
 283     struct kmac_data_st *kctx = vmacctx;
 284
 285     return kctx->out_len;
 286 }
 287
 288 static int kmac_update(void *vmacctx, const unsigned char *data,
 289                        size_t datalen)
 290 {
 291     struct kmac_data_st *kctx = vmacctx;
 292
 293     return EVP_DigestUpdate(kctx->ctx, data, datalen);
 294 }
 295
 296 static int kmac_final(void *vmacctx, unsigned char *out, size_t *outl,
 297                       size_t outsize)
 298 {
 299     struct kmac_data_st *kctx = vmacctx;
 300     EVP_MD_CTX *ctx = kctx->ctx;
 301     int lbits, len;
 302     unsigned char encoded_outlen[KMAC_MAX_ENCODED_HEADER_LEN];
 303     int ok;
 304
 305     if (!ossl_prov_is_running())
 306         return 0;
 307
 308     /* KMAC XOF mode sets the encoded length to 0 */
 309     lbits = (kctx->xof_mode ? 0 : (kctx->out_len * 8));
 310
 311     ok = right_encode(encoded_outlen, &len, lbits)
 312         && EVP_DigestUpdate(ctx, encoded_outlen, len)
 313         && EVP_DigestFinalXOF(ctx, out, kctx->out_len);
 314     *outl = kctx->out_len;
 315     return ok;
 316 }
 317
 318 static const OSSL_PARAM known_gettable_ctx_params[] = {
 319     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
 320     OSSL_PARAM_END
 321 };
 322 static const OSSL_PARAM *kmac_gettable_ctx_params(ossl_unused void *provctx)
 323 {
 324     return known_gettable_ctx_params;
 325 }
 326
 327 static int kmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
 328 {
 329     OSSL_PARAM *p;
 330
 331     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL)
 332         return OSSL_PARAM_set_size_t(p, kmac_size(vmacctx));
 333
 334     return 1;
 335 }
 336
 337 static const OSSL_PARAM known_settable_ctx_params[] = {
 338     OSSL_PARAM_int(OSSL_MAC_PARAM_XOF, NULL),
 339     OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
 340     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
 341     OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, NULL, 0),
 342     OSSL_PARAM_END
 343 };
 344 static const OSSL_PARAM *kmac_settable_ctx_params(ossl_unused void *provctx)
 345 {
 346     return known_settable_ctx_params;
 347 }
 348
 349 /*
 350  * The following params can be set any time before final():
 351  *     - "outlen" or "size":    The requested output length.
 352  *     - "xof":                 If set, this indicates that right_encoded(0)
 353  *                              is part of the digested data, otherwise it
 354  *                              uses right_encoded(requested output length).
 355  *
 356  * All other params should be set before init().
 357  */
 358 static int kmac_set_ctx_params(void *vmacctx, const OSSL_PARAM *params)
 359 {
 360     struct kmac_data_st *kctx = vmacctx;
 361     const OSSL_PARAM *p;
 362     const EVP_MD *digest = ossl_prov_digest_md(&kctx->digest);
 363
 364     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_XOF)) != NULL
 365         && !OSSL_PARAM_get_int(p, &kctx->xof_mode))
 366         return 0;
 367     if (((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_SIZE)) != NULL)
 368         && !OSSL_PARAM_get_size_t(p, &kctx->out_len))
 369         return 0;
 370     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
 371         if (p->data_size < 4 || p->data_size > KMAC_MAX_KEY) {
 372             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
 373             return 0;
 374         }
 375         if (!kmac_bytepad_encode_key(kctx->key, &kctx->key_len,
 376                                      p->data, p->data_size,
 377                                      EVP_MD_block_size(digest)))
 378             return 0;
 379     }
 380     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_CUSTOM))
 381         != NULL) {
 382         if (p->data_size > KMAC_MAX_CUSTOM) {
 383             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CUSTOM_LENGTH);
 384             return 0;
 385         }
 386         if (!encode_string(kctx->custom, &kctx->custom_len,
 387                            p->data, p->data_size))
 388             return 0;
 389     }
 390     return 1;
 391 }
 392
 393 /*
 394  * Encoding/Padding Methods.
 395  */
 396
 397 /* Returns the number of bytes required to store 'bits' into a byte array */
 398 static unsigned int get_encode_size(size_t bits)
 399 {
 400     unsigned int cnt = 0, sz = sizeof(size_t);
 401
 402     while (bits && (cnt < sz)) {
 403         ++cnt;
 404         bits >>= 8;
 405     }
 406     /* If bits is zero 1 byte is required */
 407     if (cnt == 0)
 408         cnt = 1;
 409     return cnt;
 410 }
 411
 412 /*
 413  * Convert an integer into bytes . The number of bytes is appended
 414  * to the end of the buffer. Returns an array of bytes 'out' of size
 415  * *out_len.
 416  *
 417  * e.g if bits = 32, out[2] = { 0x20, 0x01 }
 418  *
 419  */
 420 static int right_encode(unsigned char *out, int *out_len, size_t bits)
 421 {
 422     unsigned int len = get_encode_size(bits);
 423     int i;
 424
 425     /* The length is constrained to a single byte: 2040/8 = 255 */
 426     if (len > 0xFF)
 427         return 0;
 428
 429     /* MSB's are at the start of the bytes array */
 430     for (i = len - 1; i >= 0; --i) {
 431         out[i] = (unsigned char)(bits & 0xFF);
 432         bits >>= 8;
 433     }
 434     /* Tack the length onto the end */
 435     out[len] = (unsigned char)len;
 436
 437     /* The Returned length includes the tacked on byte */
 438     *out_len = len + 1;
 439     return 1;
 440 }
 441
 442 /*
 443  * Encodes a string with a left encoded length added. Note that the
 444  * in_len is converted to bits (*8).
 445  *
 446  * e.g- in="KMAC" gives out[6] = { 0x01, 0x20, 0x4B, 0x4D, 0x41, 0x43 }
 447  *                                 len   bits    K     M     A     C
 448  */
 449 static int encode_string(unsigned char *out, int *out_len,
 450                          const unsigned char *in, int in_len)
 451 {
 452     if (in == NULL) {
 453         *out_len = 0;
 454     } else {
 455         int i, bits, len;
 456
 457         bits = 8 * in_len;
 458         len = get_encode_size(bits);
 459         if (len > 0xFF)
 460             return 0;
 461
 462         out[0] = len;
 463         for (i = len; i > 0; --i) {
 464             out[i] = (bits & 0xFF);
 465             bits >>= 8;
 466         }
 467         memcpy(out + len + 1, in, in_len);
 468         *out_len = (1 + len + in_len);
 469     }
 470     return 1;
 471 }
 472
 473 /*
 474  * Returns a zero padded encoding of the inputs in1 and an optional
 475  * in2 (can be NULL). The padded output must be a multiple of the blocksize 'w'.
 476  * The value of w is in bytes (< 256).
 477  *
 478  * The returned output is:
 479  *    zero_padded(multiple of w, (left_encode(w) || in1 [|| in2])
 480  */
 481 static int bytepad(unsigned char *out, int *out_len,
 482                    const unsigned char *in1, int in1_len,
 483                    const unsigned char *in2, int in2_len, int w)
 484 {
 485     int len;
 486     unsigned char *p = out;
 487     int sz = w;
 488
 489     /* Left encoded w */
 490     *p++ = 1;
 491     *p++ = w;
 492     /* || in1 */
 493     memcpy(p, in1, in1_len);
 494     p += in1_len;
 495     /* [ || in2 ] */
 496     if (in2 != NULL && in2_len > 0) {
 497         memcpy(p, in2, in2_len);
 498         p += in2_len;
 499     }
 500     /* Figure out the pad size (divisible by w) */
 501     len = p - out;
 502     while (len > sz) {
 503         sz += w;
 504     }
 505     /* zero pad the end of the buffer */
 506     memset(p, 0, sz - len);
 507     *out_len = sz;
 508     return 1;
 509 }
 510
 511 /*
 512  * Returns out = bytepad(encode_string(in), w)
 513  */
 514 static int kmac_bytepad_encode_key(unsigned char *out, int *out_len,
 515                                    const unsigned char *in, int in_len,
 516                                    int w)
 517 {
 518     unsigned char tmp[KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN];
 519     int tmp_len;
 520
 521     if (!encode_string(tmp, &tmp_len, in, in_len))
 522         return 0;
 523
 524     return bytepad(out, out_len, tmp, tmp_len, NULL, 0, w);
 525 }
 526
 527 const OSSL_DISPATCH kmac128_functions[] = {
 528     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))kmac128_new },
 529     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))kmac_dup },
 530     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))kmac_free },
 531     { OSSL_FUNC_MAC_INIT, (void (*)(void))kmac_init },
 532     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))kmac_update },
 533     { OSSL_FUNC_MAC_FINAL, (void (*)(void))kmac_final },
 534     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
 535       (void (*)(void))kmac_gettable_ctx_params },
 536     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))kmac_get_ctx_params },
 537     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
 538       (void (*)(void))kmac_settable_ctx_params },
 539     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))kmac_set_ctx_params },
 540     { 0, NULL }
 541 };
 542
 543 const OSSL_DISPATCH kmac256_functions[] = {
 544     { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))kmac256_new },
 545     { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))kmac_dup },
 546     { OSSL_FUNC_MAC_FREECTX, (void (*)(void))kmac_free },
 547     { OSSL_FUNC_MAC_INIT, (void (*)(void))kmac_init },
 548     { OSSL_FUNC_MAC_UPDATE, (void (*)(void))kmac_update },
 549     { OSSL_FUNC_MAC_FINAL, (void (*)(void))kmac_final },
 550     { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
 551       (void (*)(void))kmac_gettable_ctx_params },
 552     { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))kmac_get_ctx_params },
 553     { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
 554       (void (*)(void))kmac_settable_ctx_params },
 555     { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))kmac_set_ctx_params },
 556     { 0, NULL }
 557 };