crypto/evp/evp_enc.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include <assert.h>
  12 #include "internal/cryptlib.h"
  13 #include <openssl/evp.h>
  14 #include <openssl/err.h>
  15 #include <openssl/rand.h>
  16 #include <openssl/engine.h>
  17 #include "internal/evp_int.h"
  18 #include "evp_locl.h"
  19
  20 int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *c)
  21 {
  22     if (c == NULL)
  23         return 1;
  24     if (c->cipher != NULL) {
  25         if (c->cipher->cleanup && !c->cipher->cleanup(c))
  26             return 0;
  27         /* Cleanse cipher context data */
  28         if (c->cipher_data && c->cipher->ctx_size)
  29             OPENSSL_cleanse(c->cipher_data, c->cipher->ctx_size);
  30     }
  31     OPENSSL_free(c->cipher_data);
  32 #ifndef OPENSSL_NO_ENGINE
  33     ENGINE_finish(c->engine);
  34 #endif
  35     memset(c, 0, sizeof(*c));
  36     return 1;
  37 }
  38
  39 EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void)
  40 {
  41     return OPENSSL_zalloc(sizeof(EVP_CIPHER_CTX));
  42 }
  43
  44 void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx)
  45 {
  46     EVP_CIPHER_CTX_reset(ctx);
  47     OPENSSL_free(ctx);
  48 }
  49
  50 int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
  51                    const unsigned char *key, const unsigned char *iv, int enc)
  52 {
  53     EVP_CIPHER_CTX_reset(ctx);
  54     return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, enc);
  55 }
  56
  57 int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
  58                       ENGINE *impl, const unsigned char *key,
  59                       const unsigned char *iv, int enc)
  60 {
  61     if (enc == -1)
  62         enc = ctx->encrypt;
  63     else {
  64         if (enc)
  65             enc = 1;
  66         ctx->encrypt = enc;
  67     }
  68 #ifndef OPENSSL_NO_ENGINE
  69     /*
  70      * Whether it's nice or not, "Inits" can be used on "Final"'d contexts so
  71      * this context may already have an ENGINE! Try to avoid releasing the
  72      * previous handle, re-querying for an ENGINE, and having a
  73      * reinitialisation, when it may all be unnecessary.
  74      */
  75     if (ctx->engine && ctx->cipher
  76         && (cipher == NULL || cipher->nid == ctx->cipher->nid))
  77         goto skip_to_init;
  78 #endif
  79     if (cipher) {
  80         /*
  81          * Ensure a context left lying around from last time is cleared (the
  82          * previous check attempted to avoid this if the same ENGINE and
  83          * EVP_CIPHER could be used).
  84          */
  85         if (ctx->cipher) {
  86             unsigned long flags = ctx->flags;
  87             EVP_CIPHER_CTX_reset(ctx);
  88             /* Restore encrypt and flags */
  89             ctx->encrypt = enc;
  90             ctx->flags = flags;
  91         }
  92 #ifndef OPENSSL_NO_ENGINE
  93         if (impl) {
  94             if (!ENGINE_init(impl)) {
  95                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
  96                 return 0;
  97             }
  98         } else
  99             /* Ask if an ENGINE is reserved for this job */
 100             impl = ENGINE_get_cipher_engine(cipher->nid);
 101         if (impl) {
 102             /* There's an ENGINE for this job ... (apparently) */
 103             const EVP_CIPHER *c = ENGINE_get_cipher(impl, cipher->nid);
 104             if (!c) {
 105                 /*
 106                  * One positive side-effect of US's export control history,
 107                  * is that we should at least be able to avoid using US
 108                  * misspellings of "initialisation"?
 109                  */
 110                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 111                 return 0;
 112             }
 113             /* We'll use the ENGINE's private cipher definition */
 114             cipher = c;
 115             /*
 116              * Store the ENGINE functional reference so we know 'cipher' came
 117              * from an ENGINE and we need to release it when done.
 118              */
 119             ctx->engine = impl;
 120         } else
 121             ctx->engine = NULL;
 122 #endif
 123
 124         ctx->cipher = cipher;
 125         if (ctx->cipher->ctx_size) {
 126             ctx->cipher_data = OPENSSL_zalloc(ctx->cipher->ctx_size);
 127             if (ctx->cipher_data == NULL) {
 128                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, ERR_R_MALLOC_FAILURE);
 129                 return 0;
 130             }
 131         } else {
 132             ctx->cipher_data = NULL;
 133         }
 134         ctx->key_len = cipher->key_len;
 135         /* Preserve wrap enable flag, zero everything else */
 136         ctx->flags &= EVP_CIPHER_CTX_FLAG_WRAP_ALLOW;
 137         if (ctx->cipher->flags & EVP_CIPH_CTRL_INIT) {
 138             if (!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_INIT, 0, NULL)) {
 139                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 140                 return 0;
 141             }
 142         }
 143     } else if (!ctx->cipher) {
 144         EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_NO_CIPHER_SET);
 145         return 0;
 146     }
 147 #ifndef OPENSSL_NO_ENGINE
 148  skip_to_init:
 149 #endif
 150     /* we assume block size is a power of 2 in *cryptUpdate */
 151     OPENSSL_assert(ctx->cipher->block_size == 1
 152                    || ctx->cipher->block_size == 8
 153                    || ctx->cipher->block_size == 16);
 154
 155     if (!(ctx->flags & EVP_CIPHER_CTX_FLAG_WRAP_ALLOW)
 156         && EVP_CIPHER_CTX_mode(ctx) == EVP_CIPH_WRAP_MODE) {
 157         EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_WRAP_MODE_NOT_ALLOWED);
 158         return 0;
 159     }
 160
 161     if (!(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ctx)) & EVP_CIPH_CUSTOM_IV)) {
 162         switch (EVP_CIPHER_CTX_mode(ctx)) {
 163
 164         case EVP_CIPH_STREAM_CIPHER:
 165         case EVP_CIPH_ECB_MODE:
 166             break;
 167
 168         case EVP_CIPH_CFB_MODE:
 169         case EVP_CIPH_OFB_MODE:
 170
 171             ctx->num = 0;
 172             /* fall-through */
 173
 174         case EVP_CIPH_CBC_MODE:
 175
 176             OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) <=
 177                            (int)sizeof(ctx->iv));
 178             if (iv)
 179                 memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 180             memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
 181             break;
 182
 183         case EVP_CIPH_CTR_MODE:
 184             ctx->num = 0;
 185             /* Don't reuse IV for CTR mode */
 186             if (iv)
 187                 memcpy(ctx->iv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 188             break;
 189
 190         default:
 191             return 0;
 192         }
 193     }
 194
 195     if (key || (ctx->cipher->flags & EVP_CIPH_ALWAYS_CALL_INIT)) {
 196         if (!ctx->cipher->init(ctx, key, iv, enc))
 197             return 0;
 198     }
 199     ctx->buf_len = 0;
 200     ctx->final_used = 0;
 201     ctx->block_mask = ctx->cipher->block_size - 1;
 202     return 1;
 203 }
 204
 205 int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 206                      const unsigned char *in, int inl)
 207 {
 208     if (ctx->encrypt)
 209         return EVP_EncryptUpdate(ctx, out, outl, in, inl);
 210     else
 211         return EVP_DecryptUpdate(ctx, out, outl, in, inl);
 212 }
 213
 214 int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 215 {
 216     if (ctx->encrypt)
 217         return EVP_EncryptFinal_ex(ctx, out, outl);
 218     else
 219         return EVP_DecryptFinal_ex(ctx, out, outl);
 220 }
 221
 222 int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 223 {
 224     if (ctx->encrypt)
 225         return EVP_EncryptFinal(ctx, out, outl);
 226     else
 227         return EVP_DecryptFinal(ctx, out, outl);
 228 }
 229
 230 int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 231                     const unsigned char *key, const unsigned char *iv)
 232 {
 233     return EVP_CipherInit(ctx, cipher, key, iv, 1);
 234 }
 235
 236 int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 237                        ENGINE *impl, const unsigned char *key,
 238                        const unsigned char *iv)
 239 {
 240     return EVP_CipherInit_ex(ctx, cipher, impl, key, iv, 1);
 241 }
 242
 243 int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 244                     const unsigned char *key, const unsigned char *iv)
 245 {
 246     return EVP_CipherInit(ctx, cipher, key, iv, 0);
 247 }
 248
 249 int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 250                        ENGINE *impl, const unsigned char *key,
 251                        const unsigned char *iv)
 252 {
 253     return EVP_CipherInit_ex(ctx, cipher, impl, key, iv, 0);
 254 }
 255
 256 /*
 257  * According to the letter of standard difference between pointers
 258  * is specified to be valid only within same object. This makes
 259  * it formally challenging to determine if input and output buffers
 260  * are not partially overlapping with standard pointer arithmetic.
 261  */
 262 #ifdef PTRDIFF_T
 263 # undef PTRDIFF_T
 264 #endif
 265 #if defined(OPENSSL_SYS_VMS) && __INITIAL_POINTER_SIZE==64
 266 /*
 267  * Then we have VMS that distinguishes itself by adhering to
 268  * sizeof(size_t)==4 even in 64-bit builds, which means that
 269  * difference between two pointers might be truncated to 32 bits.
 270  * In the context one can even wonder how comparison for
 271  * equality is implemented. To be on the safe side we adhere to
 272  * PTRDIFF_T even for comparison for equality.
 273  */
 274 # define PTRDIFF_T uint64_t
 275 #else
 276 # define PTRDIFF_T size_t
 277 #endif
 278
 279 int is_partially_overlapping(const void *ptr1, const void *ptr2, int len)
 280 {
 281     PTRDIFF_T diff = (PTRDIFF_T)ptr1-(PTRDIFF_T)ptr2;
 282     /*
 283      * Check for partially overlapping buffers. [Binary logical
 284      * operations are used instead of boolean to minimize number
 285      * of conditional branches.]
 286      */
 287     int overlapped = (len > 0) & (diff != 0) & ((diff < (PTRDIFF_T)len) |
 288                                                 (diff > (0 - (PTRDIFF_T)len)));
 289
 290     return overlapped;
 291 }
 292
 293 int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 294                       const unsigned char *in, int inl)
 295 {
 296     int i, j, bl;
 297
 298     bl = ctx->cipher->block_size;
 299
 300     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 301         /* If block size > 1 then the cipher will have to do this check */
 302         if (bl == 1 && is_partially_overlapping(out, in, inl)) {
 303             EVPerr(EVP_F_EVP_ENCRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 304             return 0;
 305         }
 306
 307         i = ctx->cipher->do_cipher(ctx, out, in, inl);
 308         if (i < 0)
 309             return 0;
 310         else
 311             *outl = i;
 312         return 1;
 313     }
 314
 315     if (inl <= 0) {
 316         *outl = 0;
 317         return inl == 0;
 318     }
 319     if (is_partially_overlapping(out + ctx->buf_len, in, inl)) {
 320         EVPerr(EVP_F_EVP_ENCRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 321         return 0;
 322     }
 323
 324     if (ctx->buf_len == 0 && (inl & (ctx->block_mask)) == 0) {
 325         if (ctx->cipher->do_cipher(ctx, out, in, inl)) {
 326             *outl = inl;
 327             return 1;
 328         } else {
 329             *outl = 0;
 330             return 0;
 331         }
 332     }
 333     i = ctx->buf_len;
 334     OPENSSL_assert(bl <= (int)sizeof(ctx->buf));
 335     if (i != 0) {
 336         if (bl - i > inl) {
 337             memcpy(&(ctx->buf[i]), in, inl);
 338             ctx->buf_len += inl;
 339             *outl = 0;
 340             return 1;
 341         } else {
 342             j = bl - i;
 343             memcpy(&(ctx->buf[i]), in, j);
 344             inl -= j;
 345             in += j;
 346             if (!ctx->cipher->do_cipher(ctx, out, ctx->buf, bl))
 347                 return 0;
 348             out += bl;
 349             *outl = bl;
 350         }
 351     } else
 352         *outl = 0;
 353     i = inl & (bl - 1);
 354     inl -= i;
 355     if (inl > 0) {
 356         if (!ctx->cipher->do_cipher(ctx, out, in, inl))
 357             return 0;
 358         *outl += inl;
 359     }
 360
 361     if (i != 0)
 362         memcpy(ctx->buf, &(in[inl]), i);
 363     ctx->buf_len = i;
 364     return 1;
 365 }
 366
 367 int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 368 {
 369     int ret;
 370     ret = EVP_EncryptFinal_ex(ctx, out, outl);
 371     return ret;
 372 }
 373
 374 int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 375 {
 376     int n, ret;
 377     unsigned int i, b, bl;
 378
 379     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 380         ret = ctx->cipher->do_cipher(ctx, out, NULL, 0);
 381         if (ret < 0)
 382             return 0;
 383         else
 384             *outl = ret;
 385         return 1;
 386     }
 387
 388     b = ctx->cipher->block_size;
 389     OPENSSL_assert(b <= sizeof ctx->buf);
 390     if (b == 1) {
 391         *outl = 0;
 392         return 1;
 393     }
 394     bl = ctx->buf_len;
 395     if (ctx->flags & EVP_CIPH_NO_PADDING) {
 396         if (bl) {
 397             EVPerr(EVP_F_EVP_ENCRYPTFINAL_EX,
 398                    EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
 399             return 0;
 400         }
 401         *outl = 0;
 402         return 1;
 403     }
 404
 405     n = b - bl;
 406     for (i = bl; i < b; i++)
 407         ctx->buf[i] = n;
 408     ret = ctx->cipher->do_cipher(ctx, out, ctx->buf, b);
 409
 410     if (ret)
 411         *outl = b;
 412
 413     return ret;
 414 }
 415
 416 int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 417                       const unsigned char *in, int inl)
 418 {
 419     int fix_len;
 420     unsigned int b;
 421
 422     b = ctx->cipher->block_size;
 423
 424     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 425         if (b == 1 && is_partially_overlapping(out, in, inl)) {
 426             EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 427             return 0;
 428         }
 429
 430         fix_len = ctx->cipher->do_cipher(ctx, out, in, inl);
 431         if (fix_len < 0) {
 432             *outl = 0;
 433             return 0;
 434         } else
 435             *outl = fix_len;
 436         return 1;
 437     }
 438
 439     if (inl <= 0) {
 440         *outl = 0;
 441         return inl == 0;
 442     }
 443
 444     if (ctx->flags & EVP_CIPH_NO_PADDING)
 445         return EVP_EncryptUpdate(ctx, out, outl, in, inl);
 446
 447     OPENSSL_assert(b <= sizeof ctx->final);
 448
 449     if (ctx->final_used) {
 450         /* see comment about PTRDIFF_T comparison above */
 451         if (((PTRDIFF_T)out == (PTRDIFF_T)in)
 452             || is_partially_overlapping(out, in, b)) {
 453             EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 454             return 0;
 455         }
 456         memcpy(out, ctx->final, b);
 457         out += b;
 458         fix_len = 1;
 459     } else
 460         fix_len = 0;
 461
 462     if (!EVP_EncryptUpdate(ctx, out, outl, in, inl))
 463         return 0;
 464
 465     /*
 466      * if we have 'decrypted' a multiple of block size, make sure we have a
 467      * copy of this last block
 468      */
 469     if (b > 1 && !ctx->buf_len) {
 470         *outl -= b;
 471         ctx->final_used = 1;
 472         memcpy(ctx->final, &out[*outl], b);
 473     } else
 474         ctx->final_used = 0;
 475
 476     if (fix_len)
 477         *outl += b;
 478
 479     return 1;
 480 }
 481
 482 int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 483 {
 484     int ret;
 485     ret = EVP_DecryptFinal_ex(ctx, out, outl);
 486     return ret;
 487 }
 488
 489 int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 490 {
 491     int i, n;
 492     unsigned int b;
 493     *outl = 0;
 494
 495     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 496         i = ctx->cipher->do_cipher(ctx, out, NULL, 0);
 497         if (i < 0)
 498             return 0;
 499         else
 500             *outl = i;
 501         return 1;
 502     }
 503
 504     b = ctx->cipher->block_size;
 505     if (ctx->flags & EVP_CIPH_NO_PADDING) {
 506         if (ctx->buf_len) {
 507             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,
 508                    EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
 509             return 0;
 510         }
 511         *outl = 0;
 512         return 1;
 513     }
 514     if (b > 1) {
 515         if (ctx->buf_len || !ctx->final_used) {
 516             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_WRONG_FINAL_BLOCK_LENGTH);
 517             return (0);
 518         }
 519         OPENSSL_assert(b <= sizeof ctx->final);
 520
 521         /*
 522          * The following assumes that the ciphertext has been authenticated.
 523          * Otherwise it provides a padding oracle.
 524          */
 525         n = ctx->final[b - 1];
 526         if (n == 0 || n > (int)b) {
 527             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_BAD_DECRYPT);
 528             return (0);
 529         }
 530         for (i = 0; i < n; i++) {
 531             if (ctx->final[--b] != n) {
 532                 EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_BAD_DECRYPT);
 533                 return (0);
 534             }
 535         }
 536         n = ctx->cipher->block_size - n;
 537         for (i = 0; i < n; i++)
 538             out[i] = ctx->final[i];
 539         *outl = n;
 540     } else
 541         *outl = 0;
 542     return (1);
 543 }
 544
 545 int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *c, int keylen)
 546 {
 547     if (c->cipher->flags & EVP_CIPH_CUSTOM_KEY_LENGTH)
 548         return EVP_CIPHER_CTX_ctrl(c, EVP_CTRL_SET_KEY_LENGTH, keylen, NULL);
 549     if (c->key_len == keylen)
 550         return 1;
 551     if ((keylen > 0) && (c->cipher->flags & EVP_CIPH_VARIABLE_LENGTH)) {
 552         c->key_len = keylen;
 553         return 1;
 554     }
 555     EVPerr(EVP_F_EVP_CIPHER_CTX_SET_KEY_LENGTH, EVP_R_INVALID_KEY_LENGTH);
 556     return 0;
 557 }
 558
 559 int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *ctx, int pad)
 560 {
 561     if (pad)
 562         ctx->flags &= ~EVP_CIPH_NO_PADDING;
 563     else
 564         ctx->flags |= EVP_CIPH_NO_PADDING;
 565     return 1;
 566 }
 567
 568 int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr)
 569 {
 570     int ret;
 571     if (!ctx->cipher) {
 572         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_NO_CIPHER_SET);
 573         return 0;
 574     }
 575
 576     if (!ctx->cipher->ctrl) {
 577         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_CTRL_NOT_IMPLEMENTED);
 578         return 0;
 579     }
 580
 581     ret = ctx->cipher->ctrl(ctx, type, arg, ptr);
 582     if (ret == -1) {
 583         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL,
 584                EVP_R_CTRL_OPERATION_NOT_IMPLEMENTED);
 585         return 0;
 586     }
 587     return ret;
 588 }
 589
 590 int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key)
 591 {
 592     if (ctx->cipher->flags & EVP_CIPH_RAND_KEY)
 593         return EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_RAND_KEY, 0, key);
 594     if (RAND_bytes(key, ctx->key_len) <= 0)
 595         return 0;
 596     return 1;
 597 }
 598
 599 int EVP_CIPHER_CTX_copy(EVP_CIPHER_CTX *out, const EVP_CIPHER_CTX *in)
 600 {
 601     if ((in == NULL) || (in->cipher == NULL)) {
 602         EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, EVP_R_INPUT_NOT_INITIALIZED);
 603         return 0;
 604     }
 605 #ifndef OPENSSL_NO_ENGINE
 606     /* Make sure it's safe to copy a cipher context using an ENGINE */
 607     if (in->engine && !ENGINE_init(in->engine)) {
 608         EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, ERR_R_ENGINE_LIB);
 609         return 0;
 610     }
 611 #endif
 612
 613     EVP_CIPHER_CTX_reset(out);
 614     memcpy(out, in, sizeof(*out));
 615
 616     if (in->cipher_data && in->cipher->ctx_size) {
 617         out->cipher_data = OPENSSL_malloc(in->cipher->ctx_size);
 618         if (out->cipher_data == NULL) {
 619             EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, ERR_R_MALLOC_FAILURE);
 620             return 0;
 621         }
 622         memcpy(out->cipher_data, in->cipher_data, in->cipher->ctx_size);
 623     }
 624
 625     if (in->cipher->flags & EVP_CIPH_CUSTOM_COPY)
 626         return in->cipher->ctrl((EVP_CIPHER_CTX *)in, EVP_CTRL_COPY, 0, out);
 627     return 1;
 628 }