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