crypto/openssl/engines/ccgost/gost_crypt.c

   1 /**********************************************************************
   2  *                          gost_crypt.c                              *
   3  *             Copyright (c) 2005-2006 Cryptocom LTD                  *
   4  *         This file is distributed under the same license as OpenSSL *
   5  *                                                                    *
   6  *       OpenSSL interface to GOST 28147-89 cipher functions          *
   7  *          Requires OpenSSL 0.9.9 for compilation                    *
   8  **********************************************************************/
   9 #include <string.h>
  10 #include "gost89.h"
  11 #include <openssl/rand.h>
  12 #include "e_gost_err.h"
  13 #include "gost_lcl.h"
  14
  15 #if !defined(CCGOST_DEBUG) && !defined(DEBUG)
  16 # ifndef NDEBUG
  17 #  define NDEBUG
  18 # endif
  19 #endif
  20 #include <assert.h>
  21
  22 static int gost_cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
  23                             const unsigned char *iv, int enc);
  24 static int gost_cipher_init_cpa(EVP_CIPHER_CTX *ctx, const unsigned char *key,
  25                                 const unsigned char *iv, int enc);
  26 /* Handles block of data in CFB mode */
  27 static int gost_cipher_do_cfb(EVP_CIPHER_CTX *ctx, unsigned char *out,
  28                               const unsigned char *in, size_t inl);
  29 /* Handles block of data in CNT mode */
  30 static int gost_cipher_do_cnt(EVP_CIPHER_CTX *ctx, unsigned char *out,
  31                               const unsigned char *in, size_t inl);
  32 /* Cleanup function */
  33 static int gost_cipher_cleanup(EVP_CIPHER_CTX *);
  34 /* set/get cipher parameters */
  35 static int gost89_set_asn1_parameters(EVP_CIPHER_CTX *ctx, ASN1_TYPE *params);
  36 static int gost89_get_asn1_parameters(EVP_CIPHER_CTX *ctx, ASN1_TYPE *params);
  37 /* Control function */
  38 static int gost_cipher_ctl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr);
  39
  40 EVP_CIPHER cipher_gost = {
  41     NID_id_Gost28147_89,
  42     1,                          /* block_size */
  43     32,                         /* key_size */
  44     8,                          /* iv_len */
  45     EVP_CIPH_CFB_MODE | EVP_CIPH_NO_PADDING |
  46         EVP_CIPH_CUSTOM_IV | EVP_CIPH_RAND_KEY | EVP_CIPH_ALWAYS_CALL_INIT,
  47     gost_cipher_init,
  48     gost_cipher_do_cfb,
  49     gost_cipher_cleanup,
  50     sizeof(struct ossl_gost_cipher_ctx), /* ctx_size */
  51     gost89_set_asn1_parameters,
  52     gost89_get_asn1_parameters,
  53     gost_cipher_ctl,
  54     NULL,
  55 };
  56
  57 EVP_CIPHER cipher_gost_cpacnt = {
  58     NID_gost89_cnt,
  59     1,                          /* block_size */
  60     32,                         /* key_size */
  61     8,                          /* iv_len */
  62     EVP_CIPH_OFB_MODE | EVP_CIPH_NO_PADDING |
  63         EVP_CIPH_CUSTOM_IV | EVP_CIPH_RAND_KEY | EVP_CIPH_ALWAYS_CALL_INIT,
  64     gost_cipher_init_cpa,
  65     gost_cipher_do_cnt,
  66     gost_cipher_cleanup,
  67     sizeof(struct ossl_gost_cipher_ctx), /* ctx_size */
  68     gost89_set_asn1_parameters,
  69     gost89_get_asn1_parameters,
  70     gost_cipher_ctl,
  71     NULL,
  72 };
  73
  74 /* Implementation of GOST 28147-89 in MAC (imitovstavka) mode */
  75 /* Init functions which set specific parameters */
  76 static int gost_imit_init_cpa(EVP_MD_CTX *ctx);
  77 /* process block of data */
  78 static int gost_imit_update(EVP_MD_CTX *ctx, const void *data, size_t count);
  79 /* Return computed value */
  80 static int gost_imit_final(EVP_MD_CTX *ctx, unsigned char *md);
  81 /* Copies context */
  82 static int gost_imit_copy(EVP_MD_CTX *to, const EVP_MD_CTX *from);
  83 static int gost_imit_cleanup(EVP_MD_CTX *ctx);
  84 /* Control function, knows how to set MAC key.*/
  85 static int gost_imit_ctrl(EVP_MD_CTX *ctx, int type, int arg, void *ptr);
  86
  87 EVP_MD imit_gost_cpa = {
  88     NID_id_Gost28147_89_MAC,
  89     NID_undef,
  90     4,
  91     0,
  92     gost_imit_init_cpa,
  93     gost_imit_update,
  94     gost_imit_final,
  95     gost_imit_copy,
  96     gost_imit_cleanup,
  97     NULL,
  98     NULL,
  99     {0, 0, 0, 0, 0},
 100     8,
 101     sizeof(struct ossl_gost_imit_ctx),
 102     gost_imit_ctrl
 103 };
 104
 105 /*
 106  * Correspondence between gost parameter OIDs and substitution blocks
 107  * NID field is filed by register_gost_NID function in engine.c
 108  * upon engine initialization
 109  */
 110
 111 struct gost_cipher_info gost_cipher_list[] = {
 112     /*- NID *//*
 113      * Subst block
 114      *//*
 115      * Key meshing
 116      */
 117     /*
 118      * {NID_id_GostR3411_94_CryptoProParamSet,&GostR3411_94_CryptoProParamSet,0},
 119      */
 120     {NID_id_Gost28147_89_cc, &GostR3411_94_CryptoProParamSet, 0},
 121     {NID_id_Gost28147_89_CryptoPro_A_ParamSet, &Gost28147_CryptoProParamSetA,
 122      1},
 123     {NID_id_Gost28147_89_CryptoPro_B_ParamSet, &Gost28147_CryptoProParamSetB,
 124      1},
 125     {NID_id_Gost28147_89_CryptoPro_C_ParamSet, &Gost28147_CryptoProParamSetC,
 126      1},
 127     {NID_id_Gost28147_89_CryptoPro_D_ParamSet, &Gost28147_CryptoProParamSetD,
 128      1},
 129     {NID_id_Gost28147_89_TestParamSet, &Gost28147_TestParamSet, 1},
 130     {NID_undef, NULL, 0}
 131 };
 132
 133 /*
 134  * get encryption parameters from crypto network settings FIXME For now we
 135  * use environment var CRYPT_PARAMS as place to store these settings.
 136  * Actually, it is better to use engine control command, read from
 137  * configuration file to set them
 138  */
 139 const struct gost_cipher_info *get_encryption_params(ASN1_OBJECT *obj)
 140 {
 141     int nid;
 142     struct gost_cipher_info *param;
 143     if (!obj) {
 144         const char *params = get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS);
 145         if (!params || !strlen(params))
 146             return &gost_cipher_list[1];
 147
 148         nid = OBJ_txt2nid(params);
 149         if (nid == NID_undef) {
 150             GOSTerr(GOST_F_GET_ENCRYPTION_PARAMS,
 151                     GOST_R_INVALID_CIPHER_PARAM_OID);
 152             return NULL;
 153         }
 154     } else {
 155         nid = OBJ_obj2nid(obj);
 156     }
 157     for (param = gost_cipher_list; param->sblock != NULL && param->nid != nid;
 158          param++) ;
 159     if (!param->sblock) {
 160         GOSTerr(GOST_F_GET_ENCRYPTION_PARAMS, GOST_R_INVALID_CIPHER_PARAMS);
 161         return NULL;
 162     }
 163     return param;
 164 }
 165
 166 /* Sets cipher param from paramset NID. */
 167 static int gost_cipher_set_param(struct ossl_gost_cipher_ctx *c, int nid)
 168 {
 169     const struct gost_cipher_info *param;
 170     param =
 171         get_encryption_params((nid == NID_undef ? NULL : OBJ_nid2obj(nid)));
 172     if (!param)
 173         return 0;
 174
 175     c->paramNID = param->nid;
 176     c->key_meshing = param->key_meshing;
 177     c->count = 0;
 178     gost_init(&(c->cctx), param->sblock);
 179     return 1;
 180 }
 181
 182 /* Initializes EVP_CIPHER_CTX by paramset NID */
 183 static int gost_cipher_init_param(EVP_CIPHER_CTX *ctx,
 184                                   const unsigned char *key,
 185                                   const unsigned char *iv, int enc,
 186                                   int paramNID, int mode)
 187 {
 188     struct ossl_gost_cipher_ctx *c = ctx->cipher_data;
 189     if (ctx->app_data == NULL) {
 190         if (!gost_cipher_set_param(c, paramNID))
 191             return 0;
 192         ctx->app_data = ctx->cipher_data;
 193     }
 194     if (key)
 195         gost_key(&(c->cctx), key);
 196     if (iv)
 197         memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 198     memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
 199     return 1;
 200 }
 201
 202 static int gost_cipher_init_cpa(EVP_CIPHER_CTX *ctx, const unsigned char *key,
 203                                 const unsigned char *iv, int enc)
 204 {
 205     struct ossl_gost_cipher_ctx *c = ctx->cipher_data;
 206     gost_init(&(c->cctx), &Gost28147_CryptoProParamSetA);
 207     c->key_meshing = 1;
 208     c->count = 0;
 209     if (key)
 210         gost_key(&(c->cctx), key);
 211     if (iv)
 212         memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 213     memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
 214     return 1;
 215 }
 216
 217 /* Initializes EVP_CIPHER_CTX with default values */
 218 int gost_cipher_init(EVP_CIPHER_CTX *ctx, const unsigned char *key,
 219                      const unsigned char *iv, int enc)
 220 {
 221     return gost_cipher_init_param(ctx, key, iv, enc, NID_undef,
 222                                   EVP_CIPH_CFB_MODE);
 223 }
 224
 225 /*
 226  * Wrapper around gostcrypt function from gost89.c which perform key meshing
 227  * when nesseccary
 228  */
 229 static void gost_crypt_mesh(void *ctx, unsigned char *iv, unsigned char *buf)
 230 {
 231     struct ossl_gost_cipher_ctx *c = ctx;
 232     assert(c->count % 8 == 0 && c->count <= 1024);
 233     if (c->key_meshing && c->count == 1024) {
 234         cryptopro_key_meshing(&(c->cctx), iv);
 235     }
 236     gostcrypt(&(c->cctx), iv, buf);
 237     c->count = c->count % 1024 + 8;
 238 }
 239
 240 static void gost_cnt_next(void *ctx, unsigned char *iv, unsigned char *buf)
 241 {
 242     struct ossl_gost_cipher_ctx *c = ctx;
 243     word32 g, go;
 244     unsigned char buf1[8];
 245     assert(c->count % 8 == 0 && c->count <= 1024);
 246     if (c->key_meshing && c->count == 1024) {
 247         cryptopro_key_meshing(&(c->cctx), iv);
 248     }
 249     if (c->count == 0) {
 250         gostcrypt(&(c->cctx), iv, buf1);
 251     } else {
 252         memcpy(buf1, iv, 8);
 253     }
 254     g = buf1[0] | (buf1[1] << 8) | (buf1[2] << 16) | ((word32) buf1[3] << 24);
 255     g += 0x01010101;
 256     buf1[0] = (unsigned char)(g & 0xff);
 257     buf1[1] = (unsigned char)((g >> 8) & 0xff);
 258     buf1[2] = (unsigned char)((g >> 16) & 0xff);
 259     buf1[3] = (unsigned char)((g >> 24) & 0xff);
 260     g = buf1[4] | (buf1[5] << 8) | (buf1[6] << 16) | ((word32) buf1[7] << 24);
 261     go = g;
 262     g += 0x01010104;
 263     if (go > g)                 /* overflow */
 264         g++;
 265     buf1[4] = (unsigned char)(g & 0xff);
 266     buf1[5] = (unsigned char)((g >> 8) & 0xff);
 267     buf1[6] = (unsigned char)((g >> 16) & 0xff);
 268     buf1[7] = (unsigned char)((g >> 24) & 0xff);
 269     memcpy(iv, buf1, 8);
 270     gostcrypt(&(c->cctx), buf1, buf);
 271     c->count = c->count % 1024 + 8;
 272 }
 273
 274 /* GOST encryption in CFB mode */
 275 int gost_cipher_do_cfb(EVP_CIPHER_CTX *ctx, unsigned char *out,
 276                        const unsigned char *in, size_t inl)
 277 {
 278     const unsigned char *in_ptr = in;
 279     unsigned char *out_ptr = out;
 280     size_t i = 0;
 281     size_t j = 0;
 282 /* process partial block if any */
 283     if (ctx->num) {
 284         for (j = ctx->num, i = 0; j < 8 && i < inl;
 285              j++, i++, in_ptr++, out_ptr++) {
 286             if (!ctx->encrypt)
 287                 ctx->buf[j + 8] = *in_ptr;
 288             *out_ptr = ctx->buf[j] ^ (*in_ptr);
 289             if (ctx->encrypt)
 290                 ctx->buf[j + 8] = *out_ptr;
 291         }
 292         if (j == 8) {
 293             memcpy(ctx->iv, ctx->buf + 8, 8);
 294             ctx->num = 0;
 295         } else {
 296             ctx->num = j;
 297             return 1;
 298         }
 299     }
 300
 301     for (; i + 8 < inl; i += 8, in_ptr += 8, out_ptr += 8) {
 302         /*
 303          * block cipher current iv
 304          */
 305         gost_crypt_mesh(ctx->cipher_data, ctx->iv, ctx->buf);
 306         /*
 307          * xor next block of input text with it and output it
 308          */
 309         /*
 310          * output this block
 311          */
 312         if (!ctx->encrypt)
 313             memcpy(ctx->iv, in_ptr, 8);
 314         for (j = 0; j < 8; j++) {
 315             out_ptr[j] = ctx->buf[j] ^ in_ptr[j];
 316         }
 317         /* Encrypt */
 318         /* Next iv is next block of cipher text */
 319         if (ctx->encrypt)
 320             memcpy(ctx->iv, out_ptr, 8);
 321     }
 322 /* Process rest of buffer */
 323     if (i < inl) {
 324         gost_crypt_mesh(ctx->cipher_data, ctx->iv, ctx->buf);
 325         if (!ctx->encrypt)
 326             memcpy(ctx->buf + 8, in_ptr, inl - i);
 327         for (j = 0; i < inl; j++, i++) {
 328             out_ptr[j] = ctx->buf[j] ^ in_ptr[j];
 329         }
 330         ctx->num = j;
 331         if (ctx->encrypt)
 332             memcpy(ctx->buf + 8, out_ptr, j);
 333     } else {
 334         ctx->num = 0;
 335     }
 336     return 1;
 337 }
 338
 339 static int gost_cipher_do_cnt(EVP_CIPHER_CTX *ctx, unsigned char *out,
 340                               const unsigned char *in, size_t inl)
 341 {
 342     const unsigned char *in_ptr = in;
 343     unsigned char *out_ptr = out;
 344     size_t i = 0;
 345     size_t j;
 346 /* process partial block if any */
 347     if (ctx->num) {
 348         for (j = ctx->num, i = 0; j < 8 && i < inl;
 349              j++, i++, in_ptr++, out_ptr++) {
 350             *out_ptr = ctx->buf[j] ^ (*in_ptr);
 351         }
 352         if (j == 8) {
 353             ctx->num = 0;
 354         } else {
 355             ctx->num = j;
 356             return 1;
 357         }
 358     }
 359
 360     for (; i + 8 < inl; i += 8, in_ptr += 8, out_ptr += 8) {
 361         /*
 362          * block cipher current iv
 363          */
 364         /* Encrypt */
 365         gost_cnt_next(ctx->cipher_data, ctx->iv, ctx->buf);
 366         /*
 367          * xor next block of input text with it and output it
 368          */
 369         /*
 370          * output this block
 371          */
 372         for (j = 0; j < 8; j++) {
 373             out_ptr[j] = ctx->buf[j] ^ in_ptr[j];
 374         }
 375     }
 376 /* Process rest of buffer */
 377     if (i < inl) {
 378         gost_cnt_next(ctx->cipher_data, ctx->iv, ctx->buf);
 379         for (j = 0; i < inl; j++, i++) {
 380             out_ptr[j] = ctx->buf[j] ^ in_ptr[j];
 381         }
 382         ctx->num = j;
 383     } else {
 384         ctx->num = 0;
 385     }
 386     return 1;
 387 }
 388
 389 /* Cleaning up of EVP_CIPHER_CTX */
 390 int gost_cipher_cleanup(EVP_CIPHER_CTX *ctx)
 391 {
 392     gost_destroy(&((struct ossl_gost_cipher_ctx *)ctx->cipher_data)->cctx);
 393     ctx->app_data = NULL;
 394     return 1;
 395 }
 396
 397 /* Control function for gost cipher */
 398 int gost_cipher_ctl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr)
 399 {
 400     switch (type) {
 401     case EVP_CTRL_RAND_KEY:
 402         {
 403             if (RAND_bytes((unsigned char *)ptr, ctx->key_len) <= 0) {
 404                 GOSTerr(GOST_F_GOST_CIPHER_CTL,
 405                         GOST_R_RANDOM_GENERATOR_ERROR);
 406                 return -1;
 407             }
 408             break;
 409         }
 410     case EVP_CTRL_PBE_PRF_NID:
 411         if (ptr) {
 412             *((int *)ptr) = NID_id_HMACGostR3411_94;
 413             return 1;
 414         } else {
 415             return 0;
 416         }
 417
 418     default:
 419         GOSTerr(GOST_F_GOST_CIPHER_CTL,
 420                 GOST_R_UNSUPPORTED_CIPHER_CTL_COMMAND);
 421         return -1;
 422     }
 423     return 1;
 424 }
 425
 426 /* Set cipher parameters from ASN1 structure */
 427 int gost89_set_asn1_parameters(EVP_CIPHER_CTX *ctx, ASN1_TYPE *params)
 428 {
 429     int len = 0;
 430     unsigned char *buf = NULL;
 431     unsigned char *p = NULL;
 432     struct ossl_gost_cipher_ctx *c = ctx->cipher_data;
 433     GOST_CIPHER_PARAMS *gcp = GOST_CIPHER_PARAMS_new();
 434     ASN1_OCTET_STRING *os = NULL;
 435     if (!gcp) {
 436         GOSTerr(GOST_F_GOST89_SET_ASN1_PARAMETERS, GOST_R_NO_MEMORY);
 437         return 0;
 438     }
 439     if (!ASN1_OCTET_STRING_set(gcp->iv, ctx->iv, ctx->cipher->iv_len)) {
 440         GOST_CIPHER_PARAMS_free(gcp);
 441         GOSTerr(GOST_F_GOST89_SET_ASN1_PARAMETERS, GOST_R_NO_MEMORY);
 442         return 0;
 443     }
 444     ASN1_OBJECT_free(gcp->enc_param_set);
 445     gcp->enc_param_set = OBJ_nid2obj(c->paramNID);
 446
 447     len = i2d_GOST_CIPHER_PARAMS(gcp, NULL);
 448     p = buf = (unsigned char *)OPENSSL_malloc(len);
 449     if (!buf) {
 450         GOST_CIPHER_PARAMS_free(gcp);
 451         GOSTerr(GOST_F_GOST89_SET_ASN1_PARAMETERS, GOST_R_NO_MEMORY);
 452         return 0;
 453     }
 454     i2d_GOST_CIPHER_PARAMS(gcp, &p);
 455     GOST_CIPHER_PARAMS_free(gcp);
 456
 457     os = ASN1_OCTET_STRING_new();
 458
 459     if (!os || !ASN1_OCTET_STRING_set(os, buf, len)) {
 460         OPENSSL_free(buf);
 461         GOSTerr(GOST_F_GOST89_SET_ASN1_PARAMETERS, GOST_R_NO_MEMORY);
 462         return 0;
 463     }
 464     OPENSSL_free(buf);
 465
 466     ASN1_TYPE_set(params, V_ASN1_SEQUENCE, os);
 467     return 1;
 468 }
 469
 470 /* Store parameters into ASN1 structure */
 471 int gost89_get_asn1_parameters(EVP_CIPHER_CTX *ctx, ASN1_TYPE *params)
 472 {
 473     int ret = -1;
 474     int len;
 475     GOST_CIPHER_PARAMS *gcp = NULL;
 476     unsigned char *p;
 477     struct ossl_gost_cipher_ctx *c = ctx->cipher_data;
 478     if (ASN1_TYPE_get(params) != V_ASN1_SEQUENCE) {
 479         return ret;
 480     }
 481
 482     p = params->value.sequence->data;
 483
 484     gcp = d2i_GOST_CIPHER_PARAMS(NULL, (const unsigned char **)&p,
 485                                  params->value.sequence->length);
 486
 487     len = gcp->iv->length;
 488     if (len != ctx->cipher->iv_len) {
 489         GOST_CIPHER_PARAMS_free(gcp);
 490         GOSTerr(GOST_F_GOST89_GET_ASN1_PARAMETERS, GOST_R_INVALID_IV_LENGTH);
 491         return -1;
 492     }
 493     if (!gost_cipher_set_param(c, OBJ_obj2nid(gcp->enc_param_set))) {
 494         GOST_CIPHER_PARAMS_free(gcp);
 495         return -1;
 496     }
 497     memcpy(ctx->oiv, gcp->iv->data, len);
 498
 499     GOST_CIPHER_PARAMS_free(gcp);
 500
 501     return 1;
 502 }
 503
 504 int gost_imit_init_cpa(EVP_MD_CTX *ctx)
 505 {
 506     struct ossl_gost_imit_ctx *c = ctx->md_data;
 507     memset(c->buffer, 0, sizeof(c->buffer));
 508     memset(c->partial_block, 0, sizeof(c->partial_block));
 509     c->count = 0;
 510     c->bytes_left = 0;
 511     c->key_meshing = 1;
 512     gost_init(&(c->cctx), &Gost28147_CryptoProParamSetA);
 513     return 1;
 514 }
 515
 516 static void mac_block_mesh(struct ossl_gost_imit_ctx *c,
 517                            const unsigned char *data)
 518 {
 519     unsigned char buffer[8];
 520     /*
 521      * We are using local buffer for iv because CryptoPro doesn't interpret
 522      * internal state of MAC algorithm as iv during keymeshing (but does
 523      * initialize internal state from iv in key transport
 524      */
 525     assert(c->count % 8 == 0 && c->count <= 1024);
 526     if (c->key_meshing && c->count == 1024) {
 527         cryptopro_key_meshing(&(c->cctx), buffer);
 528     }
 529     mac_block(&(c->cctx), c->buffer, data);
 530     c->count = c->count % 1024 + 8;
 531 }
 532
 533 int gost_imit_update(EVP_MD_CTX *ctx, const void *data, size_t count)
 534 {
 535     struct ossl_gost_imit_ctx *c = ctx->md_data;
 536     const unsigned char *p = data;
 537     size_t bytes = count, i;
 538     if (!(c->key_set)) {
 539         GOSTerr(GOST_F_GOST_IMIT_UPDATE, GOST_R_MAC_KEY_NOT_SET);
 540         return 0;
 541     }
 542     if (c->bytes_left) {
 543         for (i = c->bytes_left; i < 8 && bytes > 0; bytes--, i++, p++) {
 544             c->partial_block[i] = *p;
 545         }
 546         if (i == 8) {
 547             mac_block_mesh(c, c->partial_block);
 548         } else {
 549             c->bytes_left = i;
 550             return 1;
 551         }
 552     }
 553     while (bytes > 8) {
 554         mac_block_mesh(c, p);
 555         p += 8;
 556         bytes -= 8;
 557     }
 558     if (bytes > 0) {
 559         memcpy(c->partial_block, p, bytes);
 560     }
 561     c->bytes_left = bytes;
 562     return 1;
 563 }
 564
 565 int gost_imit_final(EVP_MD_CTX *ctx, unsigned char *md)
 566 {
 567     struct ossl_gost_imit_ctx *c = ctx->md_data;
 568     if (!c->key_set) {
 569         GOSTerr(GOST_F_GOST_IMIT_FINAL, GOST_R_MAC_KEY_NOT_SET);
 570         return 0;
 571     }
 572     if (c->count == 0 && c->bytes_left) {
 573         unsigned char buffer[8];
 574         memset(buffer, 0, 8);
 575         gost_imit_update(ctx, buffer, 8);
 576     }
 577     if (c->bytes_left) {
 578         int i;
 579         for (i = c->bytes_left; i < 8; i++) {
 580             c->partial_block[i] = 0;
 581         }
 582         mac_block_mesh(c, c->partial_block);
 583     }
 584     get_mac(c->buffer, 32, md);
 585     return 1;
 586 }
 587
 588 int gost_imit_ctrl(EVP_MD_CTX *ctx, int type, int arg, void *ptr)
 589 {
 590     switch (type) {
 591     case EVP_MD_CTRL_KEY_LEN:
 592         *((unsigned int *)(ptr)) = 32;
 593         return 1;
 594     case EVP_MD_CTRL_SET_KEY:
 595         {
 596             if (arg != 32) {
 597                 GOSTerr(GOST_F_GOST_IMIT_CTRL, GOST_R_INVALID_MAC_KEY_LENGTH);
 598                 return 0;
 599             }
 600
 601             gost_key(&(((struct ossl_gost_imit_ctx *)(ctx->md_data))->cctx),
 602                      ptr);
 603             ((struct ossl_gost_imit_ctx *)(ctx->md_data))->key_set = 1;
 604             return 1;
 605
 606         }
 607     default:
 608         return 0;
 609     }
 610 }
 611
 612 int gost_imit_copy(EVP_MD_CTX *to, const EVP_MD_CTX *from)
 613 {
 614     memcpy(to->md_data, from->md_data, sizeof(struct ossl_gost_imit_ctx));
 615     return 1;
 616 }
 617
 618 /* Clean up imit ctx */
 619 int gost_imit_cleanup(EVP_MD_CTX *ctx)
 620 {
 621     memset(ctx->md_data, 0, sizeof(struct ossl_gost_imit_ctx));
 622     return 1;
 623 }