gost_grasshopper_cipher.c

   1 /*
   2  * Maxim Tishkov 2016
   3  * This file is distributed under the same license as OpenSSL
   4  */
   5
   6 #if defined(__cplusplus)
   7 extern "C" {
   8 #endif
   9
  10 #include "gost_grasshopper_cipher.h"
  11 #include "gost_grasshopper_defines.h"
  12 #include "gost_grasshopper_math.h"
  13 #include "gost_grasshopper_core.h"
  14
  15 #include <openssl/evp.h>
  16 #include <openssl/rand.h>
  17 #include <openssl/err.h>
  18 #include <string.h>
  19
  20 #include "gost_lcl.h"
  21 #include "e_gost_err.h"
  22
  23     enum GRASSHOPPER_CIPHER_TYPE {
  24         GRASSHOPPER_CIPHER_ECB = 0,
  25         GRASSHOPPER_CIPHER_CBC,
  26         GRASSHOPPER_CIPHER_OFB,
  27         GRASSHOPPER_CIPHER_CFB,
  28         GRASSHOPPER_CIPHER_CTR,
  29         GRASSHOPPER_CIPHER_CTRACPKM,
  30     };
  31
  32     static EVP_CIPHER *gost_grasshopper_ciphers[6] = {
  33         [GRASSHOPPER_CIPHER_ECB] = NULL,
  34         [GRASSHOPPER_CIPHER_CBC] = NULL,
  35         [GRASSHOPPER_CIPHER_OFB] = NULL,
  36         [GRASSHOPPER_CIPHER_CFB] = NULL,
  37         [GRASSHOPPER_CIPHER_CTR] = NULL,
  38         [GRASSHOPPER_CIPHER_CTRACPKM] = NULL,
  39     };
  40
  41     static GRASSHOPPER_INLINE void
  42         gost_grasshopper_cipher_destroy_ofb(gost_grasshopper_cipher_ctx * c);
  43     static GRASSHOPPER_INLINE void
  44         gost_grasshopper_cipher_destroy_ctr(gost_grasshopper_cipher_ctx * c);
  45
  46     struct GRASSHOPPER_CIPHER_PARAMS {
  47         int nid;
  48         grasshopper_init_cipher_func init_cipher;
  49         grasshopper_do_cipher_func do_cipher;
  50         grasshopper_destroy_cipher_func destroy_cipher;
  51         int block_size;
  52         int ctx_size;
  53         int iv_size;
  54         bool padding;
  55     };
  56
  57     static struct GRASSHOPPER_CIPHER_PARAMS gost_cipher_params[6] = {
  58         [GRASSHOPPER_CIPHER_ECB] = {
  59                                     NID_grasshopper_ecb,
  60                                     gost_grasshopper_cipher_init_ecb,
  61                                     gost_grasshopper_cipher_do_ecb,
  62                                     NULL,
  63                                     16,
  64                                     sizeof(gost_grasshopper_cipher_ctx),
  65                                     0,
  66                                     true}
  67         ,
  68         [GRASSHOPPER_CIPHER_CBC] = {
  69                                     NID_grasshopper_cbc,
  70                                     gost_grasshopper_cipher_init_cbc,
  71                                     gost_grasshopper_cipher_do_cbc,
  72                                     NULL,
  73                                     16,
  74                                     sizeof(gost_grasshopper_cipher_ctx),
  75                                     16,
  76                                     true}
  77         ,
  78         [GRASSHOPPER_CIPHER_OFB] = {
  79                                     NID_grasshopper_ofb,
  80                                     gost_grasshopper_cipher_init_ofb,
  81                                     gost_grasshopper_cipher_do_ofb,
  82                                     gost_grasshopper_cipher_destroy_ofb,
  83                                     1,
  84                                     sizeof(gost_grasshopper_cipher_ctx_ofb),
  85                                     16,
  86                                     false}
  87         ,
  88         [GRASSHOPPER_CIPHER_CFB] = {
  89                                     NID_grasshopper_cfb,
  90                                     gost_grasshopper_cipher_init_cfb,
  91                                     gost_grasshopper_cipher_do_cfb,
  92                                     NULL,
  93                                     1,
  94                                     sizeof(gost_grasshopper_cipher_ctx),
  95                                     16,
  96                                     false}
  97         ,
  98         [GRASSHOPPER_CIPHER_CTR] = {
  99                                     NID_grasshopper_ctr,
 100                                     gost_grasshopper_cipher_init_ctr,
 101                                     gost_grasshopper_cipher_do_ctr,
 102                                     gost_grasshopper_cipher_destroy_ctr,
 103                                     1,
 104                                     sizeof(gost_grasshopper_cipher_ctx_ctr),
 105                                     /* IV size is set to match full block, to make it responsibility of
 106                                      * user to assign correct values (IV || 0), and to make naive context
 107                                      * copy possible (for software such as openssh) */
 108                                     16,
 109                                     false}
 110         ,
 111         [GRASSHOPPER_CIPHER_CTRACPKM] = {
 112                                          NID_id_tc26_cipher_gostr3412_2015_kuznyechik_ctracpkm,
 113                                          gost_grasshopper_cipher_init_ctracpkm,
 114                                          gost_grasshopper_cipher_do_ctracpkm,
 115                                          gost_grasshopper_cipher_destroy_ctr,
 116                                          1,
 117                                          sizeof
 118                                          (gost_grasshopper_cipher_ctx_ctr),
 119                                          16,
 120                                          false}
 121         ,
 122     };
 123
 124 /* first 256 bit of D from draft-irtf-cfrg-re-keying-12 */
 125     static const unsigned char ACPKM_D_2018[] = {
 126         0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /*  64 bit */
 127         0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 128 bit */
 128         0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
 129         0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 256 bit */
 130     };
 131
 132     static void acpkm_next(gost_grasshopper_cipher_ctx * c) {
 133         unsigned char newkey[GRASSHOPPER_KEY_SIZE];
 134         const int J = GRASSHOPPER_KEY_SIZE / GRASSHOPPER_BLOCK_SIZE;
 135         int n;
 136
 137         for (n = 0; n < J; n++) {
 138             const unsigned char *D_n =
 139                 &ACPKM_D_2018[n * GRASSHOPPER_BLOCK_SIZE];
 140
 141             grasshopper_encrypt_block(&c->encrypt_round_keys,
 142                                       (grasshopper_w128_t *) D_n,
 143                                       (grasshopper_w128_t *) & newkey[n *
 144                                                                       GRASSHOPPER_BLOCK_SIZE],
 145                                       &c->buffer);
 146         }
 147         gost_grasshopper_cipher_key(c, newkey);
 148     }
 149
 150 /* Set 256 bit  key into context */
 151     GRASSHOPPER_INLINE void
 152         gost_grasshopper_cipher_key(gost_grasshopper_cipher_ctx * c,
 153                                     const uint8_t *k) {
 154         int i;
 155         for (i = 0; i < 2; i++) {
 156             grasshopper_copy128(&c->key.k.k[i],
 157                                 (const grasshopper_w128_t *)(k + i * 16));
 158         }
 159         grasshopper_set_encrypt_key(&c->encrypt_round_keys, &c->key);
 160         grasshopper_set_decrypt_key(&c->decrypt_round_keys, &c->key);
 161     }
 162
 163 /* Cleans up key from context */
 164     GRASSHOPPER_INLINE void
 165         gost_grasshopper_cipher_destroy(gost_grasshopper_cipher_ctx * c) {
 166         int i;
 167         for (i = 0; i < 2; i++) {
 168             grasshopper_zero128(&c->key.k.k[i]);
 169         }
 170         for (i = 0; i < GRASSHOPPER_ROUND_KEYS_COUNT; i++) {
 171             grasshopper_zero128(&c->encrypt_round_keys.k[i]);
 172         }
 173         for (i = 0; i < GRASSHOPPER_ROUND_KEYS_COUNT; i++) {
 174             grasshopper_zero128(&c->decrypt_round_keys.k[i]);
 175         }
 176         grasshopper_zero128(&c->buffer);
 177     }
 178
 179     static GRASSHOPPER_INLINE void
 180         gost_grasshopper_cipher_destroy_ofb(gost_grasshopper_cipher_ctx * c) {
 181         gost_grasshopper_cipher_ctx_ofb *ctx =
 182             (gost_grasshopper_cipher_ctx_ofb *) c;
 183
 184         grasshopper_zero128(&ctx->buffer1);
 185     }
 186
 187     static GRASSHOPPER_INLINE void
 188         gost_grasshopper_cipher_destroy_ctr(gost_grasshopper_cipher_ctx * c) {
 189         gost_grasshopper_cipher_ctx_ctr *ctx =
 190             (gost_grasshopper_cipher_ctx_ctr *) c;
 191
 192         grasshopper_zero128(&ctx->partial_buffer);
 193     }
 194
 195     int gost_grasshopper_cipher_init(EVP_CIPHER_CTX *ctx,
 196                                      const unsigned char *key,
 197                                      const unsigned char *iv, int enc) {
 198         gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 199
 200         if (EVP_CIPHER_CTX_get_app_data(ctx) == NULL) {
 201             EVP_CIPHER_CTX_set_app_data(ctx,
 202                                         EVP_CIPHER_CTX_get_cipher_data(ctx));
 203         }
 204
 205         if (key != NULL) {
 206             gost_grasshopper_cipher_key(c, key);
 207         }
 208
 209         if (iv != NULL) {
 210             memcpy((unsigned char *)EVP_CIPHER_CTX_original_iv(ctx), iv,
 211                    EVP_CIPHER_CTX_iv_length(ctx));
 212         }
 213
 214         memcpy(EVP_CIPHER_CTX_iv_noconst(ctx),
 215                EVP_CIPHER_CTX_original_iv(ctx), EVP_CIPHER_CTX_iv_length(ctx));
 216
 217         grasshopper_zero128(&c->buffer);
 218
 219         return 1;
 220     }
 221
 222     GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ecb(EVP_CIPHER_CTX *ctx,
 223                                                             const unsigned char
 224                                                             *key,
 225                                                             const unsigned char
 226                                                             *iv, int enc) {
 227         gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 228         c->type = GRASSHOPPER_CIPHER_ECB;
 229         return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 230     }
 231
 232     GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_cbc(EVP_CIPHER_CTX *ctx,
 233                                                             const unsigned char
 234                                                             *key,
 235                                                             const unsigned char
 236                                                             *iv, int enc) {
 237         gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 238         c->type = GRASSHOPPER_CIPHER_CBC;
 239         return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 240     }
 241
 242     GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ofb(EVP_CIPHER_CTX *ctx,
 243                                                             const unsigned char
 244                                                             *key,
 245                                                             const unsigned char
 246                                                             *iv, int enc) {
 247         gost_grasshopper_cipher_ctx_ofb *c =
 248             EVP_CIPHER_CTX_get_cipher_data(ctx);
 249
 250         c->c.type = GRASSHOPPER_CIPHER_OFB;
 251
 252         grasshopper_zero128(&c->buffer1);
 253
 254         return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 255     }
 256
 257     GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_cfb(EVP_CIPHER_CTX *ctx,
 258                                                             const unsigned char
 259                                                             *key,
 260                                                             const unsigned char
 261                                                             *iv, int enc) {
 262         gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 263         c->type = GRASSHOPPER_CIPHER_CFB;
 264         return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 265     }
 266
 267     GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ctr(EVP_CIPHER_CTX *ctx,
 268                                                             const unsigned char
 269                                                             *key,
 270                                                             const unsigned char
 271                                                             *iv, int enc) {
 272         gost_grasshopper_cipher_ctx_ctr *c =
 273             EVP_CIPHER_CTX_get_cipher_data(ctx);
 274
 275         c->c.type = GRASSHOPPER_CIPHER_CTR;
 276         EVP_CIPHER_CTX_set_num(ctx, 0);
 277
 278         grasshopper_zero128(&c->partial_buffer);
 279
 280         return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 281     }
 282
 283     GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ctracpkm(EVP_CIPHER_CTX
 284                                                                  *ctx,
 285                                                                  const unsigned
 286                                                                  char *key,
 287                                                                  const unsigned
 288                                                                  char *iv,
 289                                                                  int enc) {
 290         gost_grasshopper_cipher_ctx_ctr *c =
 291             EVP_CIPHER_CTX_get_cipher_data(ctx);
 292
 293         /* NB: setting type makes EVP do_cipher callback useless */
 294         c->c.type = GRASSHOPPER_CIPHER_CTRACPKM;
 295         EVP_CIPHER_CTX_set_num(ctx, 0);
 296         c->section_size = 4096;
 297
 298         return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 299     }
 300
 301     GRASSHOPPER_INLINE int gost_grasshopper_cipher_do(EVP_CIPHER_CTX *ctx,
 302                                                       unsigned char *out,
 303                                                       const unsigned char *in,
 304                                                       size_t inl) {
 305         gost_grasshopper_cipher_ctx *c =
 306             (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 307         struct GRASSHOPPER_CIPHER_PARAMS *params = &gost_cipher_params[c->type];
 308
 309         return params->do_cipher(ctx, out, in, inl);
 310     }
 311
 312     int gost_grasshopper_cipher_do_ecb(EVP_CIPHER_CTX *ctx, unsigned char *out,
 313                                        const unsigned char *in, size_t inl) {
 314         gost_grasshopper_cipher_ctx *c =
 315             (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 316         bool encrypting = (bool) EVP_CIPHER_CTX_encrypting(ctx);
 317         const unsigned char *current_in = in;
 318         unsigned char *current_out = out;
 319         size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
 320         size_t i;
 321
 322         for (i = 0; i < blocks;
 323              i++, current_in += GRASSHOPPER_BLOCK_SIZE, current_out +=
 324              GRASSHOPPER_BLOCK_SIZE) {
 325             if (encrypting) {
 326                 grasshopper_encrypt_block(&c->encrypt_round_keys,
 327                                           (grasshopper_w128_t *) current_in,
 328                                           (grasshopper_w128_t *) current_out,
 329                                           &c->buffer);
 330             } else {
 331                 grasshopper_decrypt_block(&c->decrypt_round_keys,
 332                                           (grasshopper_w128_t *) current_in,
 333                                           (grasshopper_w128_t *) current_out,
 334                                           &c->buffer);
 335             }
 336         }
 337
 338         return 1;
 339     }
 340
 341     int gost_grasshopper_cipher_do_cbc(EVP_CIPHER_CTX *ctx, unsigned char *out,
 342                                        const unsigned char *in, size_t inl) {
 343         gost_grasshopper_cipher_ctx *c =
 344             (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 345         unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 346         bool encrypting = (bool) EVP_CIPHER_CTX_encrypting(ctx);
 347         const unsigned char *current_in = in;
 348         unsigned char *current_out = out;
 349         grasshopper_w128_t *currentInputBlock;
 350         grasshopper_w128_t *currentOutputBlock;
 351         size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
 352         size_t i;
 353         grasshopper_w128_t *currentBlock;
 354
 355         currentBlock = (grasshopper_w128_t *) iv;
 356
 357         for (i = 0; i < blocks;
 358              i++, current_in += GRASSHOPPER_BLOCK_SIZE, current_out +=
 359              GRASSHOPPER_BLOCK_SIZE) {
 360             currentInputBlock = (grasshopper_w128_t *) current_in;
 361             currentOutputBlock = (grasshopper_w128_t *) current_out;
 362             if (encrypting) {
 363                 grasshopper_append128(currentBlock, currentInputBlock);
 364                 grasshopper_encrypt_block(&c->encrypt_round_keys, currentBlock,
 365                                           currentOutputBlock, &c->buffer);
 366                 grasshopper_copy128(currentBlock, currentOutputBlock);
 367             } else {
 368                 grasshopper_decrypt_block(&c->decrypt_round_keys,
 369                                           currentInputBlock, currentOutputBlock,
 370                                           &c->buffer);
 371                 grasshopper_append128(currentOutputBlock, currentBlock);
 372                 grasshopper_copy128(currentBlock, currentInputBlock);
 373             }
 374         }
 375
 376         return 1;
 377     }
 378
 379     void inc_counter(unsigned char *counter, size_t counter_bytes) {
 380         unsigned char c;
 381         unsigned int n = counter_bytes;
 382
 383         do {
 384             --n;
 385             c = counter[n];
 386             ++c;
 387             counter[n] = c;
 388             if (c)
 389                 return;
 390         } while (n);
 391     }
 392
 393 /* increment counter (128-bit int) by 1 */
 394     static void ctr128_inc(unsigned char *counter) {
 395         inc_counter(counter, 16);
 396     }
 397
 398     int gost_grasshopper_cipher_do_ctr(EVP_CIPHER_CTX *ctx, unsigned char *out,
 399                                        const unsigned char *in, size_t inl) {
 400         gost_grasshopper_cipher_ctx_ctr *c =
 401             (gost_grasshopper_cipher_ctx_ctr *)
 402             EVP_CIPHER_CTX_get_cipher_data(ctx);
 403         unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 404         const unsigned char *current_in = in;
 405         unsigned char *current_out = out;
 406         grasshopper_w128_t *currentInputBlock;
 407         grasshopper_w128_t *currentOutputBlock;
 408         unsigned int n = EVP_CIPHER_CTX_num(ctx);
 409         size_t lasted;
 410         size_t i;
 411
 412         while (n && inl) {
 413             *(current_out++) = *(current_in++) ^ c->partial_buffer.b[n];
 414             --inl;
 415             n = (n + 1) % GRASSHOPPER_BLOCK_SIZE;
 416         }
 417         EVP_CIPHER_CTX_set_num(ctx, n);
 418         size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
 419
 420         grasshopper_w128_t *iv_buffer = (grasshopper_w128_t *) iv;
 421
 422         // full parts
 423         for (i = 0; i < blocks; i++) {
 424             currentInputBlock = (grasshopper_w128_t *) current_in;
 425             currentOutputBlock = (grasshopper_w128_t *) current_out;
 426             grasshopper_encrypt_block(&c->c.encrypt_round_keys, iv_buffer,
 427                                       currentOutputBlock, &c->c.buffer);
 428             grasshopper_append128(currentOutputBlock, currentInputBlock);
 429             ctr128_inc(iv_buffer->b);
 430             current_in += GRASSHOPPER_BLOCK_SIZE;
 431             current_out += GRASSHOPPER_BLOCK_SIZE;
 432         }
 433
 434         // last part
 435         lasted = inl - blocks * GRASSHOPPER_BLOCK_SIZE;
 436         if (lasted > 0) {
 437             currentInputBlock = (grasshopper_w128_t *) current_in;
 438             currentOutputBlock = (grasshopper_w128_t *) current_out;
 439             grasshopper_encrypt_block(&c->c.encrypt_round_keys, iv_buffer,
 440                                       &c->partial_buffer, &c->c.buffer);
 441             for (i = 0; i < lasted; i++) {
 442                 currentOutputBlock->b[i] =
 443                     c->partial_buffer.b[i] ^ currentInputBlock->b[i];
 444             }
 445             EVP_CIPHER_CTX_set_num(ctx, i);
 446             ctr128_inc(iv_buffer->b);
 447         }
 448
 449         return 1;
 450     }
 451
 452 #define GRASSHOPPER_BLOCK_MASK (GRASSHOPPER_BLOCK_SIZE - 1)
 453     static inline void apply_acpkm_grasshopper(gost_grasshopper_cipher_ctx_ctr *
 454                                                ctx, unsigned int *num) {
 455         if (!ctx->section_size || (*num < ctx->section_size))
 456             return;
 457         acpkm_next(&ctx->c);
 458         *num &= GRASSHOPPER_BLOCK_MASK;
 459     }
 460
 461 /* If meshing is not configured via ctrl (setting section_size)
 462  * this function works exactly like plain ctr */
 463     int gost_grasshopper_cipher_do_ctracpkm(EVP_CIPHER_CTX *ctx,
 464                                             unsigned char *out,
 465                                             const unsigned char *in,
 466                                             size_t inl) {
 467         gost_grasshopper_cipher_ctx_ctr *c =
 468             EVP_CIPHER_CTX_get_cipher_data(ctx);
 469         unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 470         unsigned int num = EVP_CIPHER_CTX_num(ctx);
 471
 472         while ((num & GRASSHOPPER_BLOCK_MASK) && inl) {
 473             *out++ = *in++ ^ c->partial_buffer.b[num & GRASSHOPPER_BLOCK_MASK];
 474             --inl;
 475             num++;
 476         }
 477         size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
 478         size_t i;
 479
 480         // full parts
 481         for (i = 0; i < blocks; i++) {
 482             apply_acpkm_grasshopper(c, &num);
 483             grasshopper_encrypt_block(&c->c.encrypt_round_keys,
 484                                       (grasshopper_w128_t *) iv,
 485                                       (grasshopper_w128_t *) out, &c->c.buffer);
 486             grasshopper_append128((grasshopper_w128_t *) out,
 487                                   (grasshopper_w128_t *) in);
 488             ctr128_inc(iv);
 489             in += GRASSHOPPER_BLOCK_SIZE;
 490             out += GRASSHOPPER_BLOCK_SIZE;
 491             num += GRASSHOPPER_BLOCK_SIZE;
 492         }
 493
 494         // last part
 495         size_t lasted = inl - blocks * GRASSHOPPER_BLOCK_SIZE;
 496         if (lasted > 0) {
 497             apply_acpkm_grasshopper(c, &num);
 498             grasshopper_encrypt_block(&c->c.encrypt_round_keys,
 499                                       (grasshopper_w128_t *) iv,
 500                                       &c->partial_buffer, &c->c.buffer);
 501             for (i = 0; i < lasted; i++)
 502                 out[i] = c->partial_buffer.b[i] ^ in[i];
 503             ctr128_inc(iv);
 504             num += lasted;
 505         }
 506         EVP_CIPHER_CTX_set_num(ctx, num);
 507
 508         return 1;
 509     }
 510
 511 /*
 512  * Fixed 128-bit IV implementation make shift regiser redundant.
 513  */
 514     static void gost_grasshopper_cnt_next(gost_grasshopper_cipher_ctx_ofb * ctx,
 515                                           grasshopper_w128_t * iv,
 516                                           grasshopper_w128_t * buf) {
 517         memcpy(&ctx->buffer1, iv, 16);
 518         grasshopper_encrypt_block(&ctx->c.encrypt_round_keys, &ctx->buffer1,
 519                                   buf, &ctx->c.buffer);
 520         memcpy(iv, buf, 16);
 521     }
 522
 523     int gost_grasshopper_cipher_do_ofb(EVP_CIPHER_CTX *ctx, unsigned char *out,
 524                                        const unsigned char *in, size_t inl) {
 525         gost_grasshopper_cipher_ctx_ofb *c =
 526             (gost_grasshopper_cipher_ctx_ofb *)
 527             EVP_CIPHER_CTX_get_cipher_data(ctx);
 528         const unsigned char *in_ptr = in;
 529         unsigned char *out_ptr = out;
 530         unsigned char *buf = EVP_CIPHER_CTX_buf_noconst(ctx);
 531         unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 532         int num = EVP_CIPHER_CTX_num(ctx);
 533         size_t i = 0;
 534         size_t j;
 535
 536         /* process partial block if any */
 537         if (num > 0) {
 538             for (j = (size_t)num, i = 0; j < GRASSHOPPER_BLOCK_SIZE && i < inl;
 539                  j++, i++, in_ptr++, out_ptr++) {
 540                 *out_ptr = buf[j] ^ (*in_ptr);
 541             }
 542             if (j == GRASSHOPPER_BLOCK_SIZE) {
 543                 EVP_CIPHER_CTX_set_num(ctx, 0);
 544             } else {
 545                 EVP_CIPHER_CTX_set_num(ctx, (int)j);
 546                 return 1;
 547             }
 548         }
 549
 550         for (; i + GRASSHOPPER_BLOCK_SIZE <
 551              inl;
 552              i += GRASSHOPPER_BLOCK_SIZE, in_ptr +=
 553              GRASSHOPPER_BLOCK_SIZE, out_ptr += GRASSHOPPER_BLOCK_SIZE) {
 554             /*
 555              * block cipher current iv
 556              */
 557             /* Encrypt */
 558             gost_grasshopper_cnt_next(c, (grasshopper_w128_t *) iv,
 559                                       (grasshopper_w128_t *) buf);
 560
 561             /*
 562              * xor next block of input text with it and output it
 563              */
 564             /*
 565              * output this block
 566              */
 567             for (j = 0; j < GRASSHOPPER_BLOCK_SIZE; j++) {
 568                 out_ptr[j] = buf[j] ^ in_ptr[j];
 569             }
 570         }
 571
 572         /* Process rest of buffer */
 573         if (i < inl) {
 574             gost_grasshopper_cnt_next(c, (grasshopper_w128_t *) iv,
 575                                       (grasshopper_w128_t *) buf);
 576             for (j = 0; i < inl; j++, i++) {
 577                 out_ptr[j] = buf[j] ^ in_ptr[j];
 578             }
 579             EVP_CIPHER_CTX_set_num(ctx, (int)j);
 580         } else {
 581             EVP_CIPHER_CTX_set_num(ctx, 0);
 582         }
 583
 584         return 1;
 585     }
 586
 587     int gost_grasshopper_cipher_do_cfb(EVP_CIPHER_CTX *ctx, unsigned char *out,
 588                                        const unsigned char *in, size_t inl) {
 589         gost_grasshopper_cipher_ctx *c =
 590             (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 591         const unsigned char *in_ptr = in;
 592         unsigned char *out_ptr = out;
 593         unsigned char *buf = EVP_CIPHER_CTX_buf_noconst(ctx);
 594         unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 595         bool encrypting = (bool) EVP_CIPHER_CTX_encrypting(ctx);
 596         int num = EVP_CIPHER_CTX_num(ctx);
 597         size_t i = 0;
 598         size_t j = 0;
 599
 600         /* process partial block if any */
 601         if (num > 0) {
 602             for (j = (size_t)num, i = 0; j < GRASSHOPPER_BLOCK_SIZE && i < inl;
 603                  j++, i++, in_ptr++, out_ptr++) {
 604                 if (!encrypting) {
 605                     buf[j + GRASSHOPPER_BLOCK_SIZE] = *in_ptr;
 606                 }
 607                 *out_ptr = buf[j] ^ (*in_ptr);
 608                 if (encrypting) {
 609                     buf[j + GRASSHOPPER_BLOCK_SIZE] = *out_ptr;
 610                 }
 611             }
 612             if (j == GRASSHOPPER_BLOCK_SIZE) {
 613                 memcpy(iv, buf + GRASSHOPPER_BLOCK_SIZE,
 614                        GRASSHOPPER_BLOCK_SIZE);
 615                 EVP_CIPHER_CTX_set_num(ctx, 0);
 616             } else {
 617                 EVP_CIPHER_CTX_set_num(ctx, (int)j);
 618                 return 1;
 619             }
 620         }
 621
 622         for (; i + GRASSHOPPER_BLOCK_SIZE <
 623              inl;
 624              i += GRASSHOPPER_BLOCK_SIZE, in_ptr +=
 625              GRASSHOPPER_BLOCK_SIZE, out_ptr += GRASSHOPPER_BLOCK_SIZE) {
 626             /*
 627              * block cipher current iv
 628              */
 629             grasshopper_encrypt_block(&c->encrypt_round_keys,
 630                                       (grasshopper_w128_t *) iv,
 631                                       (grasshopper_w128_t *) buf, &c->buffer);
 632             /*
 633              * xor next block of input text with it and output it
 634              */
 635             /*
 636              * output this block
 637              */
 638             if (!encrypting) {
 639                 memcpy(iv, in_ptr, GRASSHOPPER_BLOCK_SIZE);
 640             }
 641             for (j = 0; j < GRASSHOPPER_BLOCK_SIZE; j++) {
 642                 out_ptr[j] = buf[j] ^ in_ptr[j];
 643             }
 644             /* Encrypt */
 645             /* Next iv is next block of cipher text */
 646             if (encrypting) {
 647                 memcpy(iv, out_ptr, GRASSHOPPER_BLOCK_SIZE);
 648             }
 649         }
 650
 651         /* Process rest of buffer */
 652         if (i < inl) {
 653             grasshopper_encrypt_block(&c->encrypt_round_keys,
 654                                       (grasshopper_w128_t *) iv,
 655                                       (grasshopper_w128_t *) buf, &c->buffer);
 656             if (!encrypting) {
 657                 memcpy(buf + GRASSHOPPER_BLOCK_SIZE, in_ptr, inl - i);
 658             }
 659             for (j = 0; i < inl; j++, i++) {
 660                 out_ptr[j] = buf[j] ^ in_ptr[j];
 661             }
 662             EVP_CIPHER_CTX_set_num(ctx, (int)j);
 663             if (encrypting) {
 664                 memcpy(buf + GRASSHOPPER_BLOCK_SIZE, out_ptr, j);
 665             }
 666         } else {
 667             EVP_CIPHER_CTX_set_num(ctx, 0);
 668         }
 669
 670         return 1;
 671     }
 672
 673     int gost_grasshopper_cipher_cleanup(EVP_CIPHER_CTX *ctx) {
 674         gost_grasshopper_cipher_ctx *c =
 675             (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 676
 677         if (!c)
 678             return 1;
 679
 680         struct GRASSHOPPER_CIPHER_PARAMS *params = &gost_cipher_params[c->type];
 681
 682         gost_grasshopper_cipher_destroy(c);
 683         if (params->destroy_cipher != NULL) {
 684             params->destroy_cipher(c);
 685         }
 686
 687         EVP_CIPHER_CTX_set_app_data(ctx, NULL);
 688
 689         return 1;
 690     }
 691
 692     int gost_grasshopper_set_asn1_parameters(EVP_CIPHER_CTX *ctx,
 693                                              ASN1_TYPE *params) {
 694         int len = 0;
 695         unsigned char *buf = NULL;
 696         ASN1_OCTET_STRING *os = NULL;
 697
 698         os = ASN1_OCTET_STRING_new();
 699
 700         if (!os || !ASN1_OCTET_STRING_set(os, buf, len)) {
 701             OPENSSL_free(buf);
 702             GOSTerr(GOST_F_GOST_GRASSHOPPER_SET_ASN1_PARAMETERS,
 703                     ERR_R_MALLOC_FAILURE);
 704             return 0;
 705         }
 706         OPENSSL_free(buf);
 707
 708         ASN1_TYPE_set(params, V_ASN1_SEQUENCE, os);
 709         return 1;
 710     }
 711
 712     GRASSHOPPER_INLINE int gost_grasshopper_get_asn1_parameters(EVP_CIPHER_CTX
 713                                                                 *ctx,
 714                                                                 ASN1_TYPE
 715                                                                 *params) {
 716         int ret = -1;
 717
 718         if (ASN1_TYPE_get(params) != V_ASN1_SEQUENCE) {
 719             return ret;
 720         }
 721
 722         return 1;
 723     }
 724
 725     int gost_grasshopper_cipher_ctl(EVP_CIPHER_CTX *ctx, int type, int arg,
 726                                     void *ptr) {
 727         switch (type) {
 728         case EVP_CTRL_RAND_KEY:{
 729                 if (RAND_bytes
 730                     ((unsigned char *)ptr,
 731                      EVP_CIPHER_CTX_key_length(ctx)) <= 0) {
 732                     GOSTerr(GOST_F_GOST_GRASSHOPPER_CIPHER_CTL,
 733                             GOST_R_RNG_ERROR);
 734                     return -1;
 735                 }
 736                 break;
 737             }
 738         case EVP_CTRL_KEY_MESH:{
 739                 gost_grasshopper_cipher_ctx_ctr *c =
 740                     EVP_CIPHER_CTX_get_cipher_data(ctx);
 741                 if (c->c.type != GRASSHOPPER_CIPHER_CTRACPKM || !arg
 742                     || (arg % GRASSHOPPER_BLOCK_SIZE))
 743                     return -1;
 744                 c->section_size = arg;
 745                 break;
 746             }
 747         default:
 748             GOSTerr(GOST_F_GOST_GRASSHOPPER_CIPHER_CTL,
 749                     GOST_R_UNSUPPORTED_CIPHER_CTL_COMMAND);
 750             return -1;
 751         }
 752         return 1;
 753     }
 754
 755     GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_create(int
 756                                                                   cipher_type,
 757                                                                   int
 758                                                                   block_size) {
 759         return EVP_CIPHER_meth_new(cipher_type, block_size /* block_size */ ,
 760                                    GRASSHOPPER_KEY_SIZE /* key_size */ );
 761     }
 762
 763     const int cipher_gost_grasshopper_setup(EVP_CIPHER *cipher, uint8_t mode,
 764                                             int iv_size, bool padding) {
 765         return EVP_CIPHER_meth_set_iv_length(cipher, iv_size)
 766             && EVP_CIPHER_meth_set_flags(cipher,
 767                                          (unsigned long)(mode |
 768                                                          ((!padding) ?
 769                                                           EVP_CIPH_NO_PADDING :
 770                                                           0) | ((iv_size >
 771                                                                  0) ?
 772                                                                 EVP_CIPH_CUSTOM_IV
 773                                                                 : 0) |
 774                                                          EVP_CIPH_RAND_KEY |
 775                                                          EVP_CIPH_ALWAYS_CALL_INIT)
 776             )
 777             && EVP_CIPHER_meth_set_cleanup(cipher,
 778                                            gost_grasshopper_cipher_cleanup)
 779             && EVP_CIPHER_meth_set_set_asn1_params(cipher,
 780                                                    gost_grasshopper_set_asn1_parameters)
 781             && EVP_CIPHER_meth_set_get_asn1_params(cipher,
 782                                                    gost_grasshopper_get_asn1_parameters)
 783             && EVP_CIPHER_meth_set_ctrl(cipher, gost_grasshopper_cipher_ctl)
 784             && EVP_CIPHER_meth_set_do_cipher(cipher,
 785                                              gost_grasshopper_cipher_do);
 786     }
 787
 788     const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper(uint8_t mode,
 789                                                                  uint8_t num) {
 790         EVP_CIPHER **cipher;
 791         struct GRASSHOPPER_CIPHER_PARAMS *params;
 792
 793         cipher = &gost_grasshopper_ciphers[num];
 794
 795         if (*cipher == NULL) {
 796             params = &gost_cipher_params[num];
 797
 798             int nid = params->nid;
 799             grasshopper_init_cipher_func init_cipher = params->init_cipher;
 800             int block_size = params->block_size;
 801             int ctx_size = params->ctx_size;
 802             int iv_size = params->iv_size;
 803             bool padding = params->padding;
 804
 805             *cipher = cipher_gost_grasshopper_create(nid, block_size);
 806             if (*cipher == NULL) {
 807                 return NULL;
 808             }
 809
 810             if (!cipher_gost_grasshopper_setup(*cipher, mode, iv_size, padding)
 811                 || !EVP_CIPHER_meth_set_init(*cipher, init_cipher)
 812                 || !EVP_CIPHER_meth_set_impl_ctx_size(*cipher, ctx_size)) {
 813                 EVP_CIPHER_meth_free(*cipher);
 814                 *cipher = NULL;
 815             }
 816         }
 817
 818         return *cipher;
 819     }
 820
 821     const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_ecb() {
 822         return cipher_gost_grasshopper(EVP_CIPH_ECB_MODE,
 823                                        GRASSHOPPER_CIPHER_ECB);
 824     }
 825
 826     const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_cbc() {
 827         return cipher_gost_grasshopper(EVP_CIPH_CBC_MODE,
 828                                        GRASSHOPPER_CIPHER_CBC);
 829     }
 830
 831     const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_ofb() {
 832         return cipher_gost_grasshopper(EVP_CIPH_OFB_MODE,
 833                                        GRASSHOPPER_CIPHER_OFB);
 834     }
 835
 836     const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_cfb() {
 837         return cipher_gost_grasshopper(EVP_CIPH_CFB_MODE,
 838                                        GRASSHOPPER_CIPHER_CFB);
 839     }
 840
 841     const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_ctr() {
 842         return cipher_gost_grasshopper(EVP_CIPH_CTR_MODE,
 843                                        GRASSHOPPER_CIPHER_CTR);
 844     }
 845
 846     const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_ctracpkm() {
 847         return cipher_gost_grasshopper(EVP_CIPH_CTR_MODE,
 848                                        GRASSHOPPER_CIPHER_CTRACPKM);
 849     }
 850
 851     void cipher_gost_grasshopper_destroy(void) {
 852         EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_ECB]);
 853         gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_ECB] = NULL;
 854         EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CBC]);
 855         gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CBC] = NULL;
 856         EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_OFB]);
 857         gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_OFB] = NULL;
 858         EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CFB]);
 859         gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CFB] = NULL;
 860         EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CTR]);
 861         gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CTR] = NULL;
 862         EVP_CIPHER_meth_free(gost_grasshopper_ciphers
 863                              [GRASSHOPPER_CIPHER_CTRACPKM]);
 864         gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CTRACPKM] = NULL;
 865     }
 866
 867 #if defined(__cplusplus)
 868 }
 869 #endif