gost_grasshopper_cipher.c

   1 /*
   2  * Maxim Tishkov 2016
   3  * This file is distributed under the same license as OpenSSL
   4  */
   5
   6 #include "gost_grasshopper_cipher.h"
   7 #include "gost_grasshopper_defines.h"
   8 #include "gost_grasshopper_math.h"
   9 #include "gost_grasshopper_core.h"
  10
  11 #include <openssl/evp.h>
  12 #include <openssl/rand.h>
  13 #include <openssl/err.h>
  14 #include <string.h>
  15
  16 #include "gost_lcl.h"
  17 #include "e_gost_err.h"
  18
  19 enum GRASSHOPPER_CIPHER_TYPE {
  20     GRASSHOPPER_CIPHER_ECB = 0,
  21     GRASSHOPPER_CIPHER_CBC,
  22     GRASSHOPPER_CIPHER_OFB,
  23     GRASSHOPPER_CIPHER_CFB,
  24     GRASSHOPPER_CIPHER_CTR,
  25     GRASSHOPPER_CIPHER_CTRACPKM,
  26 };
  27
  28 static EVP_CIPHER *gost_grasshopper_ciphers[6] = {
  29     NULL, NULL, NULL, NULL, NULL, NULL,
  30 };
  31
  32 static GRASSHOPPER_INLINE void
  33 gost_grasshopper_cipher_destroy_ctr(gost_grasshopper_cipher_ctx * c);
  34
  35 struct GRASSHOPPER_CIPHER_PARAMS {
  36     int nid;
  37     grasshopper_init_cipher_func init_cipher;
  38     grasshopper_do_cipher_func do_cipher;
  39     grasshopper_destroy_cipher_func destroy_cipher;
  40     int block_size;
  41     int ctx_size;
  42     int iv_size;
  43     bool padding;
  44 };
  45
  46 static struct GRASSHOPPER_CIPHER_PARAMS gost_cipher_params[6] = {
  47  {
  48                                 NID_grasshopper_ecb,
  49                                 gost_grasshopper_cipher_init_ecb,
  50                                 gost_grasshopper_cipher_do_ecb,
  51                                 NULL,
  52                                 16,
  53                                 sizeof(gost_grasshopper_cipher_ctx),
  54                                 0,
  55                                 true}
  56     ,
  57     {
  58                                 NID_grasshopper_cbc,
  59                                 gost_grasshopper_cipher_init_cbc,
  60                                 gost_grasshopper_cipher_do_cbc,
  61                                 NULL,
  62                                 16,
  63                                 sizeof(gost_grasshopper_cipher_ctx),
  64                                 16,
  65                                 true}
  66     ,
  67     {
  68                                 NID_grasshopper_ofb,
  69                                 gost_grasshopper_cipher_init_ofb,
  70                                 gost_grasshopper_cipher_do_ofb,
  71                                 NULL,
  72                                 1,
  73                                 sizeof(gost_grasshopper_cipher_ctx),
  74                                 16,
  75                                 false}
  76     ,
  77     {
  78                                 NID_grasshopper_cfb,
  79                                 gost_grasshopper_cipher_init_cfb,
  80                                 gost_grasshopper_cipher_do_cfb,
  81                                 NULL,
  82                                 1,
  83                                 sizeof(gost_grasshopper_cipher_ctx),
  84                                 16,
  85                                 false}
  86     ,
  87     {
  88                                 NID_grasshopper_ctr,
  89                                 gost_grasshopper_cipher_init_ctr,
  90                                 gost_grasshopper_cipher_do_ctr,
  91                                 gost_grasshopper_cipher_destroy_ctr,
  92                                 1,
  93                                 sizeof(gost_grasshopper_cipher_ctx_ctr),
  94                                 /* IV size is set to match full block, to make it responsibility of
  95                                  * user to assign correct values (IV || 0), and to make naive context
  96                                  * copy possible (for software such as openssh) */
  97                                 16,
  98                                 false}
  99     ,
 100     {
 101                                      NID_id_tc26_cipher_gostr3412_2015_kuznyechik_ctracpkm,
 102                                      gost_grasshopper_cipher_init_ctracpkm,
 103                                      gost_grasshopper_cipher_do_ctracpkm,
 104                                      gost_grasshopper_cipher_destroy_ctr,
 105                                      1,
 106                                      sizeof(gost_grasshopper_cipher_ctx_ctr),
 107                                      16,
 108                                      false}
 109     ,
 110 };
 111
 112 /* first 256 bit of D from draft-irtf-cfrg-re-keying-12 */
 113 static const unsigned char ACPKM_D_2018[] = {
 114     0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, /*  64 bit */
 115     0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, /* 128 bit */
 116     0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
 117     0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, /* 256 bit */
 118 };
 119
 120 static void acpkm_next(gost_grasshopper_cipher_ctx * c)
 121 {
 122     unsigned char newkey[GRASSHOPPER_KEY_SIZE];
 123     const int J = GRASSHOPPER_KEY_SIZE / GRASSHOPPER_BLOCK_SIZE;
 124     int n;
 125
 126     for (n = 0; n < J; n++) {
 127         const unsigned char *D_n = &ACPKM_D_2018[n * GRASSHOPPER_BLOCK_SIZE];
 128
 129         grasshopper_encrypt_block(&c->encrypt_round_keys,
 130                                   (grasshopper_w128_t *) D_n,
 131                                   (grasshopper_w128_t *) & newkey[n *
 132                                                                   GRASSHOPPER_BLOCK_SIZE],
 133                                   &c->buffer);
 134     }
 135     gost_grasshopper_cipher_key(c, newkey);
 136 }
 137
 138 /* Set 256 bit  key into context */
 139 GRASSHOPPER_INLINE void
 140 gost_grasshopper_cipher_key(gost_grasshopper_cipher_ctx * c, const uint8_t *k)
 141 {
 142     int i;
 143     for (i = 0; i < 2; i++) {
 144         grasshopper_copy128(&c->key.k.k[i],
 145                             (const grasshopper_w128_t *)(k + i * 16));
 146     }
 147
 148     grasshopper_set_encrypt_key(&c->encrypt_round_keys, &c->key);
 149     grasshopper_set_decrypt_key(&c->decrypt_round_keys, &c->key);
 150 }
 151
 152 /* Set master 256-bit key to be used in TLSTREE calculation into context */
 153 GRASSHOPPER_INLINE void
 154 gost_grasshopper_master_key(gost_grasshopper_cipher_ctx * c, const uint8_t *k)
 155 {
 156     int i;
 157     for (i = 0; i < 2; i++) {
 158         grasshopper_copy128(&c->master_key.k.k[i],
 159                             (const grasshopper_w128_t *)(k + i * 16));
 160     }
 161 }
 162
 163 /* Cleans up key from context */
 164 GRASSHOPPER_INLINE void
 165 gost_grasshopper_cipher_destroy(gost_grasshopper_cipher_ctx * c)
 166 {
 167     int i;
 168     for (i = 0; i < 2; i++) {
 169         grasshopper_zero128(&c->key.k.k[i]);
 170         grasshopper_zero128(&c->master_key.k.k[i]);
 171     }
 172     for (i = 0; i < GRASSHOPPER_ROUND_KEYS_COUNT; i++) {
 173         grasshopper_zero128(&c->encrypt_round_keys.k[i]);
 174     }
 175     for (i = 0; i < GRASSHOPPER_ROUND_KEYS_COUNT; i++) {
 176         grasshopper_zero128(&c->decrypt_round_keys.k[i]);
 177     }
 178     grasshopper_zero128(&c->buffer);
 179 }
 180
 181 static GRASSHOPPER_INLINE void
 182 gost_grasshopper_cipher_destroy_ctr(gost_grasshopper_cipher_ctx * c)
 183 {
 184     gost_grasshopper_cipher_ctx_ctr *ctx =
 185         (gost_grasshopper_cipher_ctx_ctr *) c;
 186
 187     grasshopper_zero128(&ctx->partial_buffer);
 188 }
 189
 190 int gost_grasshopper_cipher_init(EVP_CIPHER_CTX *ctx,
 191                                  const unsigned char *key,
 192                                  const unsigned char *iv, int enc)
 193 {
 194     gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 195
 196     if (EVP_CIPHER_CTX_get_app_data(ctx) == NULL) {
 197         EVP_CIPHER_CTX_set_app_data(ctx, EVP_CIPHER_CTX_get_cipher_data(ctx));
 198     }
 199
 200     if (key != NULL) {
 201         gost_grasshopper_cipher_key(c, key);
 202         gost_grasshopper_master_key(c, key);
 203     }
 204
 205     if (iv != NULL) {
 206         memcpy((unsigned char *)EVP_CIPHER_CTX_original_iv(ctx), iv,
 207                EVP_CIPHER_CTX_iv_length(ctx));
 208     }
 209
 210     memcpy(EVP_CIPHER_CTX_iv_noconst(ctx),
 211            EVP_CIPHER_CTX_original_iv(ctx), EVP_CIPHER_CTX_iv_length(ctx));
 212
 213     grasshopper_zero128(&c->buffer);
 214
 215     return 1;
 216 }
 217
 218 GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ecb(EVP_CIPHER_CTX *ctx, const unsigned char
 219                                                         *key, const unsigned char
 220                                                         *iv, int enc)
 221 {
 222     gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 223     c->type = GRASSHOPPER_CIPHER_ECB;
 224     return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 225 }
 226
 227 GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_cbc(EVP_CIPHER_CTX *ctx, const unsigned char
 228                                                         *key, const unsigned char
 229                                                         *iv, int enc)
 230 {
 231     gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 232     c->type = GRASSHOPPER_CIPHER_CBC;
 233     return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 234 }
 235
 236 GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ofb(EVP_CIPHER_CTX *ctx, const unsigned char
 237                                                         *key, const unsigned char
 238                                                         *iv, int enc)
 239 {
 240     gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 241     c->type = GRASSHOPPER_CIPHER_OFB;
 242     return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 243 }
 244
 245 GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_cfb(EVP_CIPHER_CTX *ctx, const unsigned char
 246                                                         *key, const unsigned char
 247                                                         *iv, int enc)
 248 {
 249     gost_grasshopper_cipher_ctx *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 250     c->type = GRASSHOPPER_CIPHER_CFB;
 251     return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 252 }
 253
 254 GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ctr(EVP_CIPHER_CTX *ctx, const unsigned char
 255                                                         *key, const unsigned char
 256                                                         *iv, int enc)
 257 {
 258     gost_grasshopper_cipher_ctx_ctr *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 259
 260     c->c.type = GRASSHOPPER_CIPHER_CTR;
 261     EVP_CIPHER_CTX_set_num(ctx, 0);
 262
 263     grasshopper_zero128(&c->partial_buffer);
 264
 265     return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 266 }
 267
 268 GRASSHOPPER_INLINE int gost_grasshopper_cipher_init_ctracpkm(EVP_CIPHER_CTX
 269                                                              *ctx, const unsigned
 270                                                              char *key, const unsigned
 271                                                              char *iv, int enc)
 272 {
 273     gost_grasshopper_cipher_ctx_ctr *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 274
 275     /* NB: setting type makes EVP do_cipher callback useless */
 276     c->c.type = GRASSHOPPER_CIPHER_CTRACPKM;
 277     EVP_CIPHER_CTX_set_num(ctx, 0);
 278     c->section_size = 4096;
 279
 280     return gost_grasshopper_cipher_init(ctx, key, iv, enc);
 281 }
 282
 283 GRASSHOPPER_INLINE int gost_grasshopper_cipher_do(EVP_CIPHER_CTX *ctx,
 284                                                   unsigned char *out,
 285                                                   const unsigned char *in,
 286                                                   size_t inl)
 287 {
 288     gost_grasshopper_cipher_ctx *c =
 289         (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 290     struct GRASSHOPPER_CIPHER_PARAMS *params = &gost_cipher_params[c->type];
 291
 292     return params->do_cipher(ctx, out, in, inl);
 293 }
 294
 295 int gost_grasshopper_cipher_do_ecb(EVP_CIPHER_CTX *ctx, unsigned char *out,
 296                                    const unsigned char *in, size_t inl)
 297 {
 298     gost_grasshopper_cipher_ctx *c =
 299         (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 300     bool encrypting = (bool) EVP_CIPHER_CTX_encrypting(ctx);
 301     const unsigned char *current_in = in;
 302     unsigned char *current_out = out;
 303     size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
 304     size_t i;
 305
 306     for (i = 0; i < blocks;
 307          i++, current_in += GRASSHOPPER_BLOCK_SIZE, current_out +=
 308          GRASSHOPPER_BLOCK_SIZE) {
 309         if (encrypting) {
 310             grasshopper_encrypt_block(&c->encrypt_round_keys,
 311                                       (grasshopper_w128_t *) current_in,
 312                                       (grasshopper_w128_t *) current_out,
 313                                       &c->buffer);
 314         } else {
 315             grasshopper_decrypt_block(&c->decrypt_round_keys,
 316                                       (grasshopper_w128_t *) current_in,
 317                                       (grasshopper_w128_t *) current_out,
 318                                       &c->buffer);
 319         }
 320     }
 321
 322     return 1;
 323 }
 324
 325 int gost_grasshopper_cipher_do_cbc(EVP_CIPHER_CTX *ctx, unsigned char *out,
 326                                    const unsigned char *in, size_t inl)
 327 {
 328     gost_grasshopper_cipher_ctx *c =
 329         (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 330     unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 331     bool encrypting = (bool) EVP_CIPHER_CTX_encrypting(ctx);
 332     const unsigned char *current_in = in;
 333     unsigned char *current_out = out;
 334     grasshopper_w128_t *currentInputBlock;
 335     grasshopper_w128_t *currentOutputBlock;
 336     size_t blocks = inl / GRASSHOPPER_BLOCK_SIZE;
 337     size_t i;
 338     grasshopper_w128_t *currentBlock;
 339
 340     currentBlock = (grasshopper_w128_t *) iv;
 341
 342     for (i = 0; i < blocks;
 343          i++, current_in += GRASSHOPPER_BLOCK_SIZE, current_out +=
 344          GRASSHOPPER_BLOCK_SIZE) {
 345         currentInputBlock = (grasshopper_w128_t *) current_in;
 346         currentOutputBlock = (grasshopper_w128_t *) current_out;
 347         if (encrypting) {
 348             grasshopper_append128(currentBlock, currentInputBlock);
 349             grasshopper_encrypt_block(&c->encrypt_round_keys, currentBlock,
 350                                       currentOutputBlock, &c->buffer);
 351             grasshopper_copy128(currentBlock, currentOutputBlock);
 352         } else {
 353             grasshopper_w128_t tmp;
 354
 355             grasshopper_copy128(&tmp, currentInputBlock);
 356             grasshopper_decrypt_block(&c->decrypt_round_keys,
 357                                       currentInputBlock, currentOutputBlock,
 358                                       &c->buffer);
 359             grasshopper_append128(currentOutputBlock, currentBlock);
 360             grasshopper_copy128(currentBlock, &tmp);
 361         }
 362     }
 363
 364     return 1;
 365 }
 366
 367 void inc_counter(unsigned char *counter, size_t counter_bytes)
 368 {
 369     unsigned char c;
 370     unsigned int n = counter_bytes;
 371
 372     do {
 373         --n;
 374         c = counter[n];
 375         ++c;
 376         counter[n] = c;
 377         if (c)
 378             return;
 379     } while (n);
 380 }
 381
 382 /* increment counter (128-bit int) by 1 */
 383 static void ctr128_inc(unsigned char *counter)
 384 {
 385     inc_counter(counter, 16);
 386 }
 387
 388 int gost_grasshopper_cipher_do_ctr(EVP_CIPHER_CTX *ctx, unsigned char *out,
 389                                    const unsigned char *in, size_t inl)
 390 {
 391     gost_grasshopper_cipher_ctx_ctr *c = (gost_grasshopper_cipher_ctx_ctr *)
 392         EVP_CIPHER_CTX_get_cipher_data(ctx);
 393     unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 394     const unsigned char *current_in = in;
 395     unsigned char *current_out = out;
 396     grasshopper_w128_t *currentInputBlock;
 397     grasshopper_w128_t *currentOutputBlock;
 398     unsigned int n = EVP_CIPHER_CTX_num(ctx);
 399     size_t lasted;
 400     size_t i;
 401     size_t blocks;
 402     grasshopper_w128_t *iv_buffer;
 403     grasshopper_w128_t tmp;
 404
 405     while (n && inl) {
 406         *(current_out++) = *(current_in++) ^ c->partial_buffer.b[n];
 407         --inl;
 408         n = (n + 1) % GRASSHOPPER_BLOCK_SIZE;
 409     }
 410     EVP_CIPHER_CTX_set_num(ctx, n);
 411     blocks = inl / GRASSHOPPER_BLOCK_SIZE;
 412
 413     iv_buffer = (grasshopper_w128_t *) iv;
 414
 415     // full parts
 416     for (i = 0; i < blocks; i++) {
 417         currentInputBlock = (grasshopper_w128_t *) current_in;
 418         currentOutputBlock = (grasshopper_w128_t *) current_out;
 419         grasshopper_encrypt_block(&c->c.encrypt_round_keys, iv_buffer,
 420                                   &c->partial_buffer, &c->c.buffer);
 421         grasshopper_plus128(&tmp, &c->partial_buffer, currentInputBlock);
 422         grasshopper_copy128(currentOutputBlock, &tmp);
 423         ctr128_inc(iv_buffer->b);
 424         current_in += GRASSHOPPER_BLOCK_SIZE;
 425         current_out += GRASSHOPPER_BLOCK_SIZE;
 426     }
 427
 428     // last part
 429     lasted = inl - blocks * GRASSHOPPER_BLOCK_SIZE;
 430     if (lasted > 0) {
 431         currentInputBlock = (grasshopper_w128_t *) current_in;
 432         currentOutputBlock = (grasshopper_w128_t *) current_out;
 433         grasshopper_encrypt_block(&c->c.encrypt_round_keys, iv_buffer,
 434                                   &c->partial_buffer, &c->c.buffer);
 435         for (i = 0; i < lasted; i++) {
 436             currentOutputBlock->b[i] =
 437                 c->partial_buffer.b[i] ^ currentInputBlock->b[i];
 438         }
 439         EVP_CIPHER_CTX_set_num(ctx, i);
 440         ctr128_inc(iv_buffer->b);
 441     }
 442
 443     return 1;
 444 }
 445
 446 #define GRASSHOPPER_BLOCK_MASK (GRASSHOPPER_BLOCK_SIZE - 1)
 447 static inline void apply_acpkm_grasshopper(gost_grasshopper_cipher_ctx_ctr *
 448                                            ctx, unsigned int *num)
 449 {
 450     if (!ctx->section_size || (*num < ctx->section_size))
 451         return;
 452     acpkm_next(&ctx->c);
 453     *num &= GRASSHOPPER_BLOCK_MASK;
 454 }
 455
 456 /* If meshing is not configured via ctrl (setting section_size)
 457  * this function works exactly like plain ctr */
 458 int gost_grasshopper_cipher_do_ctracpkm(EVP_CIPHER_CTX *ctx,
 459                                         unsigned char *out,
 460                                         const unsigned char *in, size_t inl)
 461 {
 462     gost_grasshopper_cipher_ctx_ctr *c = EVP_CIPHER_CTX_get_cipher_data(ctx);
 463     unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 464     unsigned int num = EVP_CIPHER_CTX_num(ctx);
 465     size_t blocks, i, lasted;
 466     grasshopper_w128_t tmp;
 467
 468     while ((num & GRASSHOPPER_BLOCK_MASK) && inl) {
 469         *out++ = *in++ ^ c->partial_buffer.b[num & GRASSHOPPER_BLOCK_MASK];
 470         --inl;
 471         num++;
 472     }
 473     blocks = inl / GRASSHOPPER_BLOCK_SIZE;
 474
 475     // full parts
 476     for (i = 0; i < blocks; i++) {
 477         apply_acpkm_grasshopper(c, &num);
 478         grasshopper_encrypt_block(&c->c.encrypt_round_keys,
 479                                   (grasshopper_w128_t *) iv,
 480                                   (grasshopper_w128_t *) & c->partial_buffer,
 481                                   &c->c.buffer);
 482         grasshopper_plus128(&tmp, &c->partial_buffer,
 483                             (grasshopper_w128_t *) in);
 484         grasshopper_copy128((grasshopper_w128_t *) out, &tmp);
 485         ctr128_inc(iv);
 486         in += GRASSHOPPER_BLOCK_SIZE;
 487         out += GRASSHOPPER_BLOCK_SIZE;
 488         num += GRASSHOPPER_BLOCK_SIZE;
 489     }
 490
 491     // last part
 492     lasted = inl - blocks * GRASSHOPPER_BLOCK_SIZE;
 493     if (lasted > 0) {
 494         apply_acpkm_grasshopper(c, &num);
 495         grasshopper_encrypt_block(&c->c.encrypt_round_keys,
 496                                   (grasshopper_w128_t *) iv,
 497                                   &c->partial_buffer, &c->c.buffer);
 498         for (i = 0; i < lasted; i++)
 499             out[i] = c->partial_buffer.b[i] ^ in[i];
 500         ctr128_inc(iv);
 501         num += lasted;
 502     }
 503     EVP_CIPHER_CTX_set_num(ctx, num);
 504
 505     return 1;
 506 }
 507
 508 /*
 509  * Fixed 128-bit IV implementation make shift regiser redundant.
 510  */
 511 static void gost_grasshopper_cnt_next(gost_grasshopper_cipher_ctx * ctx,
 512                                       grasshopper_w128_t * iv,
 513                                       grasshopper_w128_t * buf)
 514 {
 515     grasshopper_w128_t tmp;
 516     memcpy(&tmp, iv, 16);
 517     grasshopper_encrypt_block(&ctx->encrypt_round_keys, &tmp,
 518                               buf, &ctx->buffer);
 519     memcpy(iv, buf, 16);
 520 }
 521
 522 int gost_grasshopper_cipher_do_ofb(EVP_CIPHER_CTX *ctx, unsigned char *out,
 523                                    const unsigned char *in, size_t inl)
 524 {
 525     gost_grasshopper_cipher_ctx *c = (gost_grasshopper_cipher_ctx *)
 526         EVP_CIPHER_CTX_get_cipher_data(ctx);
 527     const unsigned char *in_ptr = in;
 528     unsigned char *out_ptr = out;
 529     unsigned char *buf = EVP_CIPHER_CTX_buf_noconst(ctx);
 530     unsigned char *iv = EVP_CIPHER_CTX_iv_noconst(ctx);
 531     int num = EVP_CIPHER_CTX_num(ctx);
 532     size_t i = 0;
 533     size_t j;
 534
 535     /* process partial block if any */
 536     if (num > 0) {
 537         for (j = (size_t)num, i = 0; j < GRASSHOPPER_BLOCK_SIZE && i < inl;
 538              j++, i++, in_ptr++, out_ptr++) {
 539             *out_ptr = buf[j] ^ (*in_ptr);
 540         }
 541         if (j == GRASSHOPPER_BLOCK_SIZE) {
 542             EVP_CIPHER_CTX_set_num(ctx, 0);
 543         } else {
 544             EVP_CIPHER_CTX_set_num(ctx, (int)j);
 545             return 1;
 546         }
 547     }
 548
 549     for (; i + GRASSHOPPER_BLOCK_SIZE <
 550          inl;
 551          i += GRASSHOPPER_BLOCK_SIZE, in_ptr +=
 552          GRASSHOPPER_BLOCK_SIZE, out_ptr += GRASSHOPPER_BLOCK_SIZE) {
 553         /*
 554          * block cipher current iv
 555          */
 556         /* Encrypt */
 557         gost_grasshopper_cnt_next(c, (grasshopper_w128_t *) iv,
 558                                   (grasshopper_w128_t *) buf);
 559
 560         /*
 561          * xor next block of input text with it and output it
 562          */
 563         /*
 564          * output this block
 565          */
 566         for (j = 0; j < GRASSHOPPER_BLOCK_SIZE; j++) {
 567             out_ptr[j] = buf[j] ^ in_ptr[j];
 568         }
 569     }
 570
 571     /* Process rest of buffer */
 572     if (i < inl) {
 573         gost_grasshopper_cnt_next(c, (grasshopper_w128_t *) iv,
 574                                   (grasshopper_w128_t *) buf);
 575         for (j = 0; i < inl; j++, i++) {
 576             out_ptr[j] = buf[j] ^ in_ptr[j];
 577         }
 578         EVP_CIPHER_CTX_set_num(ctx, (int)j);
 579     } else {
 580         EVP_CIPHER_CTX_set_num(ctx, 0);
 581     }
 582
 583     return 1;
 584 }
 585
 586 int gost_grasshopper_cipher_do_cfb(EVP_CIPHER_CTX *ctx, unsigned char *out,
 587                                    const unsigned char *in, size_t inl)
 588 {
 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, GRASSHOPPER_BLOCK_SIZE);
 614             EVP_CIPHER_CTX_set_num(ctx, 0);
 615         } else {
 616             EVP_CIPHER_CTX_set_num(ctx, (int)j);
 617             return 1;
 618         }
 619     }
 620
 621     for (; i + GRASSHOPPER_BLOCK_SIZE <
 622          inl;
 623          i += GRASSHOPPER_BLOCK_SIZE, in_ptr +=
 624          GRASSHOPPER_BLOCK_SIZE, out_ptr += GRASSHOPPER_BLOCK_SIZE) {
 625         /*
 626          * block cipher current iv
 627          */
 628         grasshopper_encrypt_block(&c->encrypt_round_keys,
 629                                   (grasshopper_w128_t *) iv,
 630                                   (grasshopper_w128_t *) buf, &c->buffer);
 631         /*
 632          * xor next block of input text with it and output it
 633          */
 634         /*
 635          * output this block
 636          */
 637         if (!encrypting) {
 638             memcpy(iv, in_ptr, GRASSHOPPER_BLOCK_SIZE);
 639         }
 640         for (j = 0; j < GRASSHOPPER_BLOCK_SIZE; j++) {
 641             out_ptr[j] = buf[j] ^ in_ptr[j];
 642         }
 643         /* Encrypt */
 644         /* Next iv is next block of cipher text */
 645         if (encrypting) {
 646             memcpy(iv, out_ptr, GRASSHOPPER_BLOCK_SIZE);
 647         }
 648     }
 649
 650     /* Process rest of buffer */
 651     if (i < inl) {
 652         grasshopper_encrypt_block(&c->encrypt_round_keys,
 653                                   (grasshopper_w128_t *) iv,
 654                                   (grasshopper_w128_t *) buf, &c->buffer);
 655         if (!encrypting) {
 656             memcpy(buf + GRASSHOPPER_BLOCK_SIZE, in_ptr, inl - i);
 657         }
 658         for (j = 0; i < inl; j++, i++) {
 659             out_ptr[j] = buf[j] ^ in_ptr[j];
 660         }
 661         EVP_CIPHER_CTX_set_num(ctx, (int)j);
 662         if (encrypting) {
 663             memcpy(buf + GRASSHOPPER_BLOCK_SIZE, out_ptr, j);
 664         }
 665     } else {
 666         EVP_CIPHER_CTX_set_num(ctx, 0);
 667     }
 668
 669     return 1;
 670 }
 671
 672 int gost_grasshopper_cipher_cleanup(EVP_CIPHER_CTX *ctx)
 673 {
 674     struct GRASSHOPPER_CIPHER_PARAMS *params;
 675     gost_grasshopper_cipher_ctx *c =
 676         (gost_grasshopper_cipher_ctx *) EVP_CIPHER_CTX_get_cipher_data(ctx);
 677
 678     if (!c)
 679         return 1;
 680
 681     params = &gost_cipher_params[c->type];
 682
 683     gost_grasshopper_cipher_destroy(c);
 684     if (params->destroy_cipher != NULL) {
 685         params->destroy_cipher(c);
 686     }
 687
 688     EVP_CIPHER_CTX_set_app_data(ctx, NULL);
 689
 690     return 1;
 691 }
 692
 693 int gost_grasshopper_set_asn1_parameters(EVP_CIPHER_CTX *ctx, ASN1_TYPE *params)
 694 {
 695     int len = 0;
 696     unsigned char *buf = NULL;
 697     ASN1_OCTET_STRING *os = NULL;
 698
 699     os = ASN1_OCTET_STRING_new();
 700
 701     if (!os || !ASN1_OCTET_STRING_set(os, buf, len)) {
 702         ASN1_OCTET_STRING_free(os);
 703         OPENSSL_free(buf);
 704         GOSTerr(GOST_F_GOST_GRASSHOPPER_SET_ASN1_PARAMETERS,
 705                 ERR_R_MALLOC_FAILURE);
 706         return 0;
 707     }
 708     OPENSSL_free(buf);
 709
 710     ASN1_TYPE_set(params, V_ASN1_SEQUENCE, os);
 711     return 1;
 712 }
 713
 714 GRASSHOPPER_INLINE int gost_grasshopper_get_asn1_parameters(EVP_CIPHER_CTX
 715                                                             *ctx, ASN1_TYPE
 716                                                             *params)
 717 {
 718     int ret = -1;
 719
 720     if (ASN1_TYPE_get(params) != V_ASN1_SEQUENCE) {
 721         return ret;
 722     }
 723
 724     return 1;
 725 }
 726
 727 int gost_grasshopper_cipher_ctl(EVP_CIPHER_CTX *ctx, int type, int arg,
 728                                 void *ptr)
 729 {
 730     switch (type) {
 731     case EVP_CTRL_RAND_KEY:{
 732             if (RAND_bytes
 733                 ((unsigned char *)ptr, EVP_CIPHER_CTX_key_length(ctx)) <= 0) {
 734                 GOSTerr(GOST_F_GOST_GRASSHOPPER_CIPHER_CTL, GOST_R_RNG_ERROR);
 735                 return -1;
 736             }
 737             break;
 738         }
 739     case EVP_CTRL_KEY_MESH:{
 740             gost_grasshopper_cipher_ctx_ctr *c =
 741                 EVP_CIPHER_CTX_get_cipher_data(ctx);
 742             if (c->c.type != GRASSHOPPER_CIPHER_CTRACPKM || !arg
 743                 || (arg % GRASSHOPPER_BLOCK_SIZE))
 744                 return -1;
 745             c->section_size = arg;
 746             break;
 747         }
 748 #ifdef EVP_CTRL_TLS1_2_TLSTREE
 749     case EVP_CTRL_TLS1_2_TLSTREE:
 750         {
 751           unsigned char newkey[32];
 752           int mode = EVP_CIPHER_CTX_mode(ctx);
 753           static const unsigned char zeroseq[8];
 754           gost_grasshopper_cipher_ctx_ctr *ctr_ctx = NULL;
 755           gost_grasshopper_cipher_ctx *c = NULL;
 756
 757           unsigned char adjusted_iv[16];
 758           unsigned char seq[8];
 759           int j, carry;
 760           if (mode != EVP_CIPH_CTR_MODE)
 761             return -1;
 762
 763           ctr_ctx = (gost_grasshopper_cipher_ctx_ctr *)
 764             EVP_CIPHER_CTX_get_cipher_data(ctx);
 765           c = &(ctr_ctx->c);
 766
 767           memcpy(seq, ptr, 8);
 768           if (EVP_CIPHER_CTX_encrypting(ctx)) {
 769             /*
 770              * OpenSSL increments seq after mac calculation.
 771              * As we have Mac-Then-Encrypt, we need decrement it here on encryption
 772              * to derive the key correctly.
 773              * */
 774             if (memcmp(seq, zeroseq, 8) != 0)
 775             {
 776               for(j=7; j>=0; j--)
 777               {
 778                 if (seq[j] != 0) {seq[j]--; break;}
 779                 else seq[j]  = 0xFF;
 780               }
 781             }
 782           }
 783           if (gost_tlstree(NID_grasshopper_cbc, c->master_key.k.b, newkey,
 784                 (const unsigned char *)seq) > 0) {
 785             memset(adjusted_iv, 0, 16);
 786             memcpy(adjusted_iv, EVP_CIPHER_CTX_original_iv(ctx), 8);
 787             for(j=7,carry=0; j>=0; j--)
 788             {
 789               int adj_byte = adjusted_iv[j]+seq[j]+carry;
 790               carry = (adj_byte > 255) ? 1 : 0;
 791               adjusted_iv[j] = adj_byte & 0xFF;
 792             }
 793             EVP_CIPHER_CTX_set_num(ctx, 0);
 794             memcpy(EVP_CIPHER_CTX_iv_noconst(ctx), adjusted_iv, 16);
 795
 796             gost_grasshopper_cipher_key(c, newkey);
 797             return 1;
 798           }
 799         }
 800         return -1;
 801 #endif
 802     default:
 803         GOSTerr(GOST_F_GOST_GRASSHOPPER_CIPHER_CTL,
 804                 GOST_R_UNSUPPORTED_CIPHER_CTL_COMMAND);
 805         return -1;
 806     }
 807     return 1;
 808 }
 809
 810 GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_create(int
 811                                                               cipher_type, int
 812                                                               block_size)
 813 {
 814     return EVP_CIPHER_meth_new(cipher_type, block_size /* block_size */ ,
 815                                GRASSHOPPER_KEY_SIZE /* key_size */ );
 816 }
 817
 818 const int cipher_gost_grasshopper_setup(EVP_CIPHER *cipher, uint8_t mode,
 819                                         int iv_size, bool padding)
 820 {
 821     return EVP_CIPHER_meth_set_iv_length(cipher, iv_size)
 822         && EVP_CIPHER_meth_set_flags(cipher,
 823                                      (unsigned long)(mode |
 824                                                      ((!padding) ?
 825                                                       EVP_CIPH_NO_PADDING :
 826                                                       0) | ((iv_size >
 827                                                              0) ?
 828                                                             EVP_CIPH_CUSTOM_IV
 829                                                             : 0) |
 830                                                      EVP_CIPH_RAND_KEY |
 831                                                      EVP_CIPH_ALWAYS_CALL_INIT)
 832         )
 833         && EVP_CIPHER_meth_set_cleanup(cipher, gost_grasshopper_cipher_cleanup)
 834         && EVP_CIPHER_meth_set_set_asn1_params(cipher,
 835                                                gost_grasshopper_set_asn1_parameters)
 836         && EVP_CIPHER_meth_set_get_asn1_params(cipher,
 837                                                gost_grasshopper_get_asn1_parameters)
 838         && EVP_CIPHER_meth_set_ctrl(cipher, gost_grasshopper_cipher_ctl)
 839         && EVP_CIPHER_meth_set_do_cipher(cipher, gost_grasshopper_cipher_do);
 840 }
 841
 842 const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper(uint8_t mode,
 843                                                              uint8_t num)
 844 {
 845     EVP_CIPHER **cipher;
 846     struct GRASSHOPPER_CIPHER_PARAMS *params;
 847
 848     cipher = &gost_grasshopper_ciphers[num];
 849
 850     if (*cipher == NULL) {
 851         grasshopper_init_cipher_func init_cipher;
 852         int nid, block_size, ctx_size, iv_size;
 853         bool padding;
 854
 855         params = &gost_cipher_params[num];
 856
 857         nid = params->nid;
 858         init_cipher = params->init_cipher;
 859         block_size = params->block_size;
 860         ctx_size = params->ctx_size;
 861         iv_size = params->iv_size;
 862         padding = params->padding;
 863
 864         *cipher = cipher_gost_grasshopper_create(nid, block_size);
 865         if (*cipher == NULL) {
 866             return NULL;
 867         }
 868
 869         if (!cipher_gost_grasshopper_setup(*cipher, mode, iv_size, padding)
 870             || !EVP_CIPHER_meth_set_init(*cipher, init_cipher)
 871             || !EVP_CIPHER_meth_set_impl_ctx_size(*cipher, ctx_size)) {
 872             EVP_CIPHER_meth_free(*cipher);
 873             *cipher = NULL;
 874         }
 875     }
 876
 877     return *cipher;
 878 }
 879
 880 const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_ecb()
 881 {
 882     return cipher_gost_grasshopper(EVP_CIPH_ECB_MODE, GRASSHOPPER_CIPHER_ECB);
 883 }
 884
 885 const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_cbc()
 886 {
 887     return cipher_gost_grasshopper(EVP_CIPH_CBC_MODE, GRASSHOPPER_CIPHER_CBC);
 888 }
 889
 890 const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_ofb()
 891 {
 892     return cipher_gost_grasshopper(EVP_CIPH_OFB_MODE, GRASSHOPPER_CIPHER_OFB);
 893 }
 894
 895 const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_cfb()
 896 {
 897     return cipher_gost_grasshopper(EVP_CIPH_CFB_MODE, GRASSHOPPER_CIPHER_CFB);
 898 }
 899
 900 const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_ctr()
 901 {
 902     return cipher_gost_grasshopper(EVP_CIPH_CTR_MODE, GRASSHOPPER_CIPHER_CTR);
 903 }
 904
 905 const GRASSHOPPER_INLINE EVP_CIPHER *cipher_gost_grasshopper_ctracpkm()
 906 {
 907     return cipher_gost_grasshopper(EVP_CIPH_CTR_MODE,
 908                                    GRASSHOPPER_CIPHER_CTRACPKM);
 909 }
 910
 911 void cipher_gost_grasshopper_destroy(void)
 912 {
 913     EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_ECB]);
 914     gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_ECB] = NULL;
 915     EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CBC]);
 916     gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CBC] = NULL;
 917     EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_OFB]);
 918     gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_OFB] = NULL;
 919     EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CFB]);
 920     gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CFB] = NULL;
 921     EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CTR]);
 922     gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CTR] = NULL;
 923     EVP_CIPHER_meth_free(gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CTRACPKM]);
 924     gost_grasshopper_ciphers[GRASSHOPPER_CIPHER_CTRACPKM] = NULL;
 925 }