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/rand_drbg.h>
  17 #include <openssl/engine.h>
  18 #include "internal/evp_int.h"
  19 #include "evp_locl.h"
  20
  21 int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *c)
  22 {
  23     if (c == NULL)
  24         return 1;
  25     if (c->cipher != NULL) {
  26         if (c->cipher->cleanup && !c->cipher->cleanup(c))
  27             return 0;
  28         /* Cleanse cipher context data */
  29         if (c->cipher_data && c->cipher->ctx_size)
  30             OPENSSL_cleanse(c->cipher_data, c->cipher->ctx_size);
  31     }
  32     OPENSSL_free(c->cipher_data);
  33 #ifndef OPENSSL_NO_ENGINE
  34     ENGINE_finish(c->engine);
  35 #endif
  36     memset(c, 0, sizeof(*c));
  37     return 1;
  38 }
  39
  40 EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void)
  41 {
  42     return OPENSSL_zalloc(sizeof(EVP_CIPHER_CTX));
  43 }
  44
  45 void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx)
  46 {
  47     EVP_CIPHER_CTX_reset(ctx);
  48     OPENSSL_free(ctx);
  49 }
  50
  51 int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
  52                    const unsigned char *key, const unsigned char *iv, int enc)
  53 {
  54     if (cipher != NULL)
  55         EVP_CIPHER_CTX_reset(ctx);
  56     return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, enc);
  57 }
  58
  59 int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
  60                       ENGINE *impl, const unsigned char *key,
  61                       const unsigned char *iv, int enc)
  62 {
  63     if (enc == -1)
  64         enc = ctx->encrypt;
  65     else {
  66         if (enc)
  67             enc = 1;
  68         ctx->encrypt = enc;
  69     }
  70 #ifndef OPENSSL_NO_ENGINE
  71     /*
  72      * Whether it's nice or not, "Inits" can be used on "Final"'d contexts so
  73      * this context may already have an ENGINE! Try to avoid releasing the
  74      * previous handle, re-querying for an ENGINE, and having a
  75      * reinitialisation, when it may all be unnecessary.
  76      */
  77     if (ctx->engine && ctx->cipher
  78         && (cipher == NULL || cipher->nid == ctx->cipher->nid))
  79         goto skip_to_init;
  80 #endif
  81     if (cipher) {
  82         /*
  83          * Ensure a context left lying around from last time is cleared (the
  84          * previous check attempted to avoid this if the same ENGINE and
  85          * EVP_CIPHER could be used).
  86          */
  87         if (ctx->cipher) {
  88             unsigned long flags = ctx->flags;
  89             EVP_CIPHER_CTX_reset(ctx);
  90             /* Restore encrypt and flags */
  91             ctx->encrypt = enc;
  92             ctx->flags = flags;
  93         }
  94 #ifndef OPENSSL_NO_ENGINE
  95         if (impl) {
  96             if (!ENGINE_init(impl)) {
  97                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
  98                 return 0;
  99             }
 100         } else
 101             /* Ask if an ENGINE is reserved for this job */
 102             impl = ENGINE_get_cipher_engine(cipher->nid);
 103         if (impl) {
 104             /* There's an ENGINE for this job ... (apparently) */
 105             const EVP_CIPHER *c = ENGINE_get_cipher(impl, cipher->nid);
 106             if (!c) {
 107                 /*
 108                  * One positive side-effect of US's export control history,
 109                  * is that we should at least be able to avoid using US
 110                  * misspellings of "initialisation"?
 111                  */
 112                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 113                 return 0;
 114             }
 115             /* We'll use the ENGINE's private cipher definition */
 116             cipher = c;
 117             /*
 118              * Store the ENGINE functional reference so we know 'cipher' came
 119              * from an ENGINE and we need to release it when done.
 120              */
 121             ctx->engine = impl;
 122         } else
 123             ctx->engine = NULL;
 124 #endif
 125
 126         ctx->cipher = cipher;
 127         if (ctx->cipher->ctx_size) {
 128             ctx->cipher_data = OPENSSL_zalloc(ctx->cipher->ctx_size);
 129             if (ctx->cipher_data == NULL) {
 130                 ctx->cipher = NULL;
 131                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, ERR_R_MALLOC_FAILURE);
 132                 return 0;
 133             }
 134         } else {
 135             ctx->cipher_data = NULL;
 136         }
 137         ctx->key_len = cipher->key_len;
 138         /* Preserve wrap enable flag, zero everything else */
 139         ctx->flags &= EVP_CIPHER_CTX_FLAG_WRAP_ALLOW;
 140         if (ctx->cipher->flags & EVP_CIPH_CTRL_INIT) {
 141             if (!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_INIT, 0, NULL)) {
 142                 ctx->cipher = NULL;
 143                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 144                 return 0;
 145             }
 146         }
 147     } else if (!ctx->cipher) {
 148         EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_NO_CIPHER_SET);
 149         return 0;
 150     }
 151 #ifndef OPENSSL_NO_ENGINE
 152  skip_to_init:
 153 #endif
 154     /* we assume block size is a power of 2 in *cryptUpdate */
 155     OPENSSL_assert(ctx->cipher->block_size == 1
 156                    || ctx->cipher->block_size == 8
 157                    || ctx->cipher->block_size == 16);
 158
 159     if (!(ctx->flags & EVP_CIPHER_CTX_FLAG_WRAP_ALLOW)
 160         && EVP_CIPHER_CTX_mode(ctx) == EVP_CIPH_WRAP_MODE) {
 161         EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_WRAP_MODE_NOT_ALLOWED);
 162         return 0;
 163     }
 164
 165     if (!(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ctx)) & EVP_CIPH_CUSTOM_IV)) {
 166         switch (EVP_CIPHER_CTX_mode(ctx)) {
 167
 168         case EVP_CIPH_STREAM_CIPHER:
 169         case EVP_CIPH_ECB_MODE:
 170             break;
 171
 172         case EVP_CIPH_CFB_MODE:
 173         case EVP_CIPH_OFB_MODE:
 174
 175             ctx->num = 0;
 176             /* fall-through */
 177
 178         case EVP_CIPH_CBC_MODE:
 179
 180             OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) <=
 181                            (int)sizeof(ctx->iv));
 182             if (iv)
 183                 memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 184             memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
 185             break;
 186
 187         case EVP_CIPH_CTR_MODE:
 188             ctx->num = 0;
 189             /* Don't reuse IV for CTR mode */
 190             if (iv)
 191                 memcpy(ctx->iv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 192             break;
 193
 194         default:
 195             return 0;
 196         }
 197     }
 198
 199     if (key || (ctx->cipher->flags & EVP_CIPH_ALWAYS_CALL_INIT)) {
 200         if (!ctx->cipher->init(ctx, key, iv, enc))
 201             return 0;
 202     }
 203     ctx->buf_len = 0;
 204     ctx->final_used = 0;
 205     ctx->block_mask = ctx->cipher->block_size - 1;
 206     return 1;
 207 }
 208
 209 int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 210                      const unsigned char *in, int inl)
 211 {
 212     if (ctx->encrypt)
 213         return EVP_EncryptUpdate(ctx, out, outl, in, inl);
 214     else
 215         return EVP_DecryptUpdate(ctx, out, outl, in, inl);
 216 }
 217
 218 int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 219 {
 220     if (ctx->encrypt)
 221         return EVP_EncryptFinal_ex(ctx, out, outl);
 222     else
 223         return EVP_DecryptFinal_ex(ctx, out, outl);
 224 }
 225
 226 int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 227 {
 228     if (ctx->encrypt)
 229         return EVP_EncryptFinal(ctx, out, outl);
 230     else
 231         return EVP_DecryptFinal(ctx, out, outl);
 232 }
 233
 234 int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 235                     const unsigned char *key, const unsigned char *iv)
 236 {
 237     return EVP_CipherInit(ctx, cipher, key, iv, 1);
 238 }
 239
 240 int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 241                        ENGINE *impl, const unsigned char *key,
 242                        const unsigned char *iv)
 243 {
 244     return EVP_CipherInit_ex(ctx, cipher, impl, key, iv, 1);
 245 }
 246
 247 int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 248                     const unsigned char *key, const unsigned char *iv)
 249 {
 250     return EVP_CipherInit(ctx, cipher, key, iv, 0);
 251 }
 252
 253 int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 254                        ENGINE *impl, const unsigned char *key,
 255                        const unsigned char *iv)
 256 {
 257     return EVP_CipherInit_ex(ctx, cipher, impl, key, iv, 0);
 258 }
 259
 260 /*
 261  * According to the letter of standard difference between pointers
 262  * is specified to be valid only within same object. This makes
 263  * it formally challenging to determine if input and output buffers
 264  * are not partially overlapping with standard pointer arithmetic.
 265  */
 266 #ifdef PTRDIFF_T
 267 # undef PTRDIFF_T
 268 #endif
 269 #if defined(OPENSSL_SYS_VMS) && __INITIAL_POINTER_SIZE==64
 270 /*
 271  * Then we have VMS that distinguishes itself by adhering to
 272  * sizeof(size_t)==4 even in 64-bit builds, which means that
 273  * difference between two pointers might be truncated to 32 bits.
 274  * In the context one can even wonder how comparison for
 275  * equality is implemented. To be on the safe side we adhere to
 276  * PTRDIFF_T even for comparison for equality.
 277  */
 278 # define PTRDIFF_T uint64_t
 279 #else
 280 # define PTRDIFF_T size_t
 281 #endif
 282
 283 int is_partially_overlapping(const void *ptr1, const void *ptr2, int len)
 284 {
 285     PTRDIFF_T diff = (PTRDIFF_T)ptr1-(PTRDIFF_T)ptr2;
 286     /*
 287      * Check for partially overlapping buffers. [Binary logical
 288      * operations are used instead of boolean to minimize number
 289      * of conditional branches.]
 290      */
 291     int overlapped = (len > 0) & (diff != 0) & ((diff < (PTRDIFF_T)len) |
 292                                                 (diff > (0 - (PTRDIFF_T)len)));
 293
 294     return overlapped;
 295 }
 296
 297 int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 298                       const unsigned char *in, int inl)
 299 {
 300     int i, j, bl, cmpl = inl;
 301
 302     if (EVP_CIPHER_CTX_test_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS))
 303         cmpl = (cmpl + 7) / 8;
 304
 305     bl = ctx->cipher->block_size;
 306
 307     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 308         /* If block size > 1 then the cipher will have to do this check */
 309         if (bl == 1 && is_partially_overlapping(out, in, cmpl)) {
 310             EVPerr(EVP_F_EVP_ENCRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 311             return 0;
 312         }
 313
 314         i = ctx->cipher->do_cipher(ctx, out, in, inl);
 315         if (i < 0)
 316             return 0;
 317         else
 318             *outl = i;
 319         return 1;
 320     }
 321
 322     if (inl <= 0) {
 323         *outl = 0;
 324         return inl == 0;
 325     }
 326     if (is_partially_overlapping(out + ctx->buf_len, in, cmpl)) {
 327         EVPerr(EVP_F_EVP_ENCRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 328         return 0;
 329     }
 330
 331     if (ctx->buf_len == 0 && (inl & (ctx->block_mask)) == 0) {
 332         if (ctx->cipher->do_cipher(ctx, out, in, inl)) {
 333             *outl = inl;
 334             return 1;
 335         } else {
 336             *outl = 0;
 337             return 0;
 338         }
 339     }
 340     i = ctx->buf_len;
 341     OPENSSL_assert(bl <= (int)sizeof(ctx->buf));
 342     if (i != 0) {
 343         if (bl - i > inl) {
 344             memcpy(&(ctx->buf[i]), in, inl);
 345             ctx->buf_len += inl;
 346             *outl = 0;
 347             return 1;
 348         } else {
 349             j = bl - i;
 350             memcpy(&(ctx->buf[i]), in, j);
 351             inl -= j;
 352             in += j;
 353             if (!ctx->cipher->do_cipher(ctx, out, ctx->buf, bl))
 354                 return 0;
 355             out += bl;
 356             *outl = bl;
 357         }
 358     } else
 359         *outl = 0;
 360     i = inl & (bl - 1);
 361     inl -= i;
 362     if (inl > 0) {
 363         if (!ctx->cipher->do_cipher(ctx, out, in, inl))
 364             return 0;
 365         *outl += inl;
 366     }
 367
 368     if (i != 0)
 369         memcpy(ctx->buf, &(in[inl]), i);
 370     ctx->buf_len = i;
 371     return 1;
 372 }
 373
 374 int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 375 {
 376     int ret;
 377     ret = EVP_EncryptFinal_ex(ctx, out, outl);
 378     return ret;
 379 }
 380
 381 int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 382 {
 383     int n, ret;
 384     unsigned int i, b, bl;
 385
 386     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 387         ret = ctx->cipher->do_cipher(ctx, out, NULL, 0);
 388         if (ret < 0)
 389             return 0;
 390         else
 391             *outl = ret;
 392         return 1;
 393     }
 394
 395     b = ctx->cipher->block_size;
 396     OPENSSL_assert(b <= sizeof(ctx->buf));
 397     if (b == 1) {
 398         *outl = 0;
 399         return 1;
 400     }
 401     bl = ctx->buf_len;
 402     if (ctx->flags & EVP_CIPH_NO_PADDING) {
 403         if (bl) {
 404             EVPerr(EVP_F_EVP_ENCRYPTFINAL_EX,
 405                    EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
 406             return 0;
 407         }
 408         *outl = 0;
 409         return 1;
 410     }
 411
 412     n = b - bl;
 413     for (i = bl; i < b; i++)
 414         ctx->buf[i] = n;
 415     ret = ctx->cipher->do_cipher(ctx, out, ctx->buf, b);
 416
 417     if (ret)
 418         *outl = b;
 419
 420     return ret;
 421 }
 422
 423 int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 424                       const unsigned char *in, int inl)
 425 {
 426     int fix_len, cmpl = inl;
 427     unsigned int b;
 428
 429     b = ctx->cipher->block_size;
 430
 431     if (EVP_CIPHER_CTX_test_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS))
 432         cmpl = (cmpl + 7) / 8;
 433
 434     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 435         if (b == 1 && is_partially_overlapping(out, in, cmpl)) {
 436             EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 437             return 0;
 438         }
 439
 440         fix_len = ctx->cipher->do_cipher(ctx, out, in, inl);
 441         if (fix_len < 0) {
 442             *outl = 0;
 443             return 0;
 444         } else
 445             *outl = fix_len;
 446         return 1;
 447     }
 448
 449     if (inl <= 0) {
 450         *outl = 0;
 451         return inl == 0;
 452     }
 453
 454     if (ctx->flags & EVP_CIPH_NO_PADDING)
 455         return EVP_EncryptUpdate(ctx, out, outl, in, inl);
 456
 457     OPENSSL_assert(b <= sizeof(ctx->final));
 458
 459     if (ctx->final_used) {
 460         /* see comment about PTRDIFF_T comparison above */
 461         if (((PTRDIFF_T)out == (PTRDIFF_T)in)
 462             || is_partially_overlapping(out, in, b)) {
 463             EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 464             return 0;
 465         }
 466         memcpy(out, ctx->final, b);
 467         out += b;
 468         fix_len = 1;
 469     } else
 470         fix_len = 0;
 471
 472     if (!EVP_EncryptUpdate(ctx, out, outl, in, inl))
 473         return 0;
 474
 475     /*
 476      * if we have 'decrypted' a multiple of block size, make sure we have a
 477      * copy of this last block
 478      */
 479     if (b > 1 && !ctx->buf_len) {
 480         *outl -= b;
 481         ctx->final_used = 1;
 482         memcpy(ctx->final, &out[*outl], b);
 483     } else
 484         ctx->final_used = 0;
 485
 486     if (fix_len)
 487         *outl += b;
 488
 489     return 1;
 490 }
 491
 492 int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 493 {
 494     int ret;
 495     ret = EVP_DecryptFinal_ex(ctx, out, outl);
 496     return ret;
 497 }
 498
 499 int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 500 {
 501     int i, n;
 502     unsigned int b;
 503     *outl = 0;
 504
 505     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 506         i = ctx->cipher->do_cipher(ctx, out, NULL, 0);
 507         if (i < 0)
 508             return 0;
 509         else
 510             *outl = i;
 511         return 1;
 512     }
 513
 514     b = ctx->cipher->block_size;
 515     if (ctx->flags & EVP_CIPH_NO_PADDING) {
 516         if (ctx->buf_len) {
 517             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,
 518                    EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
 519             return 0;
 520         }
 521         *outl = 0;
 522         return 1;
 523     }
 524     if (b > 1) {
 525         if (ctx->buf_len || !ctx->final_used) {
 526             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_WRONG_FINAL_BLOCK_LENGTH);
 527             return 0;
 528         }
 529         OPENSSL_assert(b <= sizeof(ctx->final));
 530
 531         /*
 532          * The following assumes that the ciphertext has been authenticated.
 533          * Otherwise it provides a padding oracle.
 534          */
 535         n = ctx->final[b - 1];
 536         if (n == 0 || n > (int)b) {
 537             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_BAD_DECRYPT);
 538             return 0;
 539         }
 540         for (i = 0; i < n; i++) {
 541             if (ctx->final[--b] != n) {
 542                 EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_BAD_DECRYPT);
 543                 return 0;
 544             }
 545         }
 546         n = ctx->cipher->block_size - n;
 547         for (i = 0; i < n; i++)
 548             out[i] = ctx->final[i];
 549         *outl = n;
 550     } else
 551         *outl = 0;
 552     return 1;
 553 }
 554
 555 int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *c, int keylen)
 556 {
 557     if (c->cipher->flags & EVP_CIPH_CUSTOM_KEY_LENGTH)
 558         return EVP_CIPHER_CTX_ctrl(c, EVP_CTRL_SET_KEY_LENGTH, keylen, NULL);
 559     if (c->key_len == keylen)
 560         return 1;
 561     if ((keylen > 0) && (c->cipher->flags & EVP_CIPH_VARIABLE_LENGTH)) {
 562         c->key_len = keylen;
 563         return 1;
 564     }
 565     EVPerr(EVP_F_EVP_CIPHER_CTX_SET_KEY_LENGTH, EVP_R_INVALID_KEY_LENGTH);
 566     return 0;
 567 }
 568
 569 int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *ctx, int pad)
 570 {
 571     if (pad)
 572         ctx->flags &= ~EVP_CIPH_NO_PADDING;
 573     else
 574         ctx->flags |= EVP_CIPH_NO_PADDING;
 575     return 1;
 576 }
 577
 578 int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr)
 579 {
 580     int ret;
 581
 582     if (!ctx->cipher) {
 583         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_NO_CIPHER_SET);
 584         return 0;
 585     }
 586
 587     if (!ctx->cipher->ctrl) {
 588         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_CTRL_NOT_IMPLEMENTED);
 589         return 0;
 590     }
 591
 592     ret = ctx->cipher->ctrl(ctx, type, arg, ptr);
 593     if (ret == -1) {
 594         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL,
 595                EVP_R_CTRL_OPERATION_NOT_IMPLEMENTED);
 596         return 0;
 597     }
 598     return ret;
 599 }
 600
 601 int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key)
 602 {
 603     if (ctx->cipher->flags & EVP_CIPH_RAND_KEY)
 604         return EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_RAND_KEY, 0, key);
 605     if (RAND_bytes(key, ctx->key_len) <= 0)
 606         return 0;
 607     return 1;
 608 }
 609
 610 int EVP_CIPHER_CTX_copy(EVP_CIPHER_CTX *out, const EVP_CIPHER_CTX *in)
 611 {
 612     if ((in == NULL) || (in->cipher == NULL)) {
 613         EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, EVP_R_INPUT_NOT_INITIALIZED);
 614         return 0;
 615     }
 616 #ifndef OPENSSL_NO_ENGINE
 617     /* Make sure it's safe to copy a cipher context using an ENGINE */
 618     if (in->engine && !ENGINE_init(in->engine)) {
 619         EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, ERR_R_ENGINE_LIB);
 620         return 0;
 621     }
 622 #endif
 623
 624     EVP_CIPHER_CTX_reset(out);
 625     memcpy(out, in, sizeof(*out));
 626
 627     if (in->cipher_data && in->cipher->ctx_size) {
 628         out->cipher_data = OPENSSL_malloc(in->cipher->ctx_size);
 629         if (out->cipher_data == NULL) {
 630             out->cipher = NULL;
 631             EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, ERR_R_MALLOC_FAILURE);
 632             return 0;
 633         }
 634         memcpy(out->cipher_data, in->cipher_data, in->cipher->ctx_size);
 635     }
 636
 637     if (in->cipher->flags & EVP_CIPH_CUSTOM_COPY)
 638         if (!in->cipher->ctrl((EVP_CIPHER_CTX *)in, EVP_CTRL_COPY, 0, out)) {
 639             out->cipher = NULL;
 640             EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, EVP_R_INITIALIZATION_ERROR);
 641             return 0;
 642         }
 643     return 1;
 644 }