crypto/evp/evp_enc.c

   1 /*
   2  * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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 <openssl/params.h>
  19 #include <openssl/core_names.h>
  20 #include "internal/evp_int.h"
  21 #include "internal/provider.h"
  22 #include "evp_locl.h"
  23
  24 int EVP_CIPHER_CTX_reset(EVP_CIPHER_CTX *ctx)
  25 {
  26     if (ctx == NULL)
  27         return 1;
  28
  29     if (ctx->cipher == NULL || ctx->cipher->prov == NULL)
  30         goto legacy;
  31
  32     if (ctx->provctx != NULL) {
  33         if (ctx->cipher->freectx != NULL)
  34             ctx->cipher->freectx(ctx->provctx);
  35         ctx->provctx = NULL;
  36     }
  37     if (ctx->fetched_cipher != NULL)
  38         EVP_CIPHER_meth_free(ctx->fetched_cipher);
  39     memset(ctx, 0, sizeof(*ctx));
  40
  41     return 1;
  42
  43     /* TODO(3.0): Remove legacy code below */
  44  legacy:
  45
  46     if (ctx->cipher != NULL) {
  47         if (ctx->cipher->cleanup && !ctx->cipher->cleanup(ctx))
  48             return 0;
  49         /* Cleanse cipher context data */
  50         if (ctx->cipher_data && ctx->cipher->ctx_size)
  51             OPENSSL_cleanse(ctx->cipher_data, ctx->cipher->ctx_size);
  52     }
  53     OPENSSL_free(ctx->cipher_data);
  54 #ifndef OPENSSL_NO_ENGINE
  55     ENGINE_finish(ctx->engine);
  56 #endif
  57     memset(ctx, 0, sizeof(*ctx));
  58     return 1;
  59 }
  60
  61 EVP_CIPHER_CTX *EVP_CIPHER_CTX_new(void)
  62 {
  63     return OPENSSL_zalloc(sizeof(EVP_CIPHER_CTX));
  64 }
  65
  66 void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *ctx)
  67 {
  68     EVP_CIPHER_CTX_reset(ctx);
  69     OPENSSL_free(ctx);
  70 }
  71
  72 int EVP_CipherInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
  73                    const unsigned char *key, const unsigned char *iv, int enc)
  74 {
  75     if (cipher != NULL)
  76         EVP_CIPHER_CTX_reset(ctx);
  77     return EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, enc);
  78 }
  79
  80 int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
  81                       ENGINE *impl, const unsigned char *key,
  82                       const unsigned char *iv, int enc)
  83 {
  84     EVP_CIPHER *provciph = NULL;
  85     ENGINE *tmpimpl = NULL;
  86     const EVP_CIPHER *tmpcipher;
  87
  88     /*
  89      * enc == 1 means we are encrypting.
  90      * enc == 0 means we are decrypting.
  91      * enc == -1 means, use the previously initialised value for encrypt/decrypt
  92      */
  93     if (enc == -1) {
  94         enc = ctx->encrypt;
  95     } else {
  96         if (enc)
  97             enc = 1;
  98         ctx->encrypt = enc;
  99     }
 100
 101     if (cipher == NULL && ctx->cipher == NULL) {
 102         EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_NO_CIPHER_SET);
 103         return 0;
 104     }
 105
 106     /* TODO(3.0): Legacy work around code below. Remove this */
 107
 108 #ifndef OPENSSL_NO_ENGINE
 109     /*
 110      * Whether it's nice or not, "Inits" can be used on "Final"'d contexts so
 111      * this context may already have an ENGINE! Try to avoid releasing the
 112      * previous handle, re-querying for an ENGINE, and having a
 113      * reinitialisation, when it may all be unnecessary.
 114      */
 115     if (ctx->engine && ctx->cipher
 116         && (cipher == NULL || cipher->nid == ctx->cipher->nid))
 117         goto skip_to_init;
 118
 119     if (cipher != NULL && impl == NULL) {
 120          /* Ask if an ENGINE is reserved for this job */
 121         tmpimpl = ENGINE_get_cipher_engine(cipher->nid);
 122     }
 123 #endif
 124
 125     /*
 126      * If there are engines involved then we should use legacy handling for now.
 127      */
 128     if (ctx->engine != NULL
 129             || impl != NULL
 130             || tmpimpl != NULL) {
 131         if (ctx->cipher == ctx->fetched_cipher)
 132             ctx->cipher = NULL;
 133         EVP_CIPHER_meth_free(ctx->fetched_cipher);
 134         ctx->fetched_cipher = NULL;
 135         goto legacy;
 136     }
 137
 138     tmpcipher = (cipher == NULL) ? ctx->cipher : cipher;
 139
 140     if (tmpcipher->prov == NULL) {
 141         switch(tmpcipher->nid) {
 142         case NID_aes_256_ecb:
 143         case NID_aes_192_ecb:
 144         case NID_aes_128_ecb:
 145         case NID_aes_256_cbc:
 146         case NID_aes_192_cbc:
 147         case NID_aes_128_cbc:
 148         case NID_aes_256_ofb128:
 149         case NID_aes_192_ofb128:
 150         case NID_aes_128_ofb128:
 151             break;
 152         default:
 153             goto legacy;
 154         }
 155     }
 156
 157     /*
 158      * Ensure a context left lying around from last time is cleared
 159      * (legacy code)
 160      */
 161     if (cipher != NULL && ctx->cipher != NULL) {
 162         OPENSSL_clear_free(ctx->cipher_data, ctx->cipher->ctx_size);
 163         ctx->cipher_data = NULL;
 164     }
 165
 166
 167     /* TODO(3.0): Start of non-legacy code below */
 168
 169     /* Ensure a context left lying around from last time is cleared */
 170     if (cipher != NULL && ctx->cipher != NULL) {
 171         unsigned long flags = ctx->flags;
 172
 173         EVP_CIPHER_CTX_reset(ctx);
 174         /* Restore encrypt and flags */
 175         ctx->encrypt = enc;
 176         ctx->flags = flags;
 177     }
 178
 179     if (cipher != NULL)
 180         ctx->cipher = cipher;
 181     else
 182         cipher = ctx->cipher;
 183
 184     if (cipher->prov == NULL) {
 185         provciph = EVP_CIPHER_fetch(NULL, OBJ_nid2sn(cipher->nid), "");
 186         if (provciph == NULL) {
 187             EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 188             return 0;
 189         }
 190         cipher = provciph;
 191         EVP_CIPHER_meth_free(ctx->fetched_cipher);
 192         ctx->fetched_cipher = provciph;
 193     }
 194
 195     ctx->cipher = cipher;
 196     if (ctx->provctx == NULL) {
 197         ctx->provctx = ctx->cipher->newctx();
 198         if (ctx->provctx == NULL) {
 199             EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 200             return 0;
 201         }
 202     }
 203
 204     if ((ctx->flags & EVP_CIPH_NO_PADDING) != 0) {
 205         /*
 206          * If this ctx was already set up for no padding then we need to tell
 207          * the new cipher about it.
 208          */
 209         if (!EVP_CIPHER_CTX_set_padding(ctx, 0))
 210             return 0;
 211     }
 212
 213     switch (EVP_CIPHER_mode(ctx->cipher)) {
 214     case EVP_CIPH_CFB_MODE:
 215     case EVP_CIPH_OFB_MODE:
 216     case EVP_CIPH_CBC_MODE:
 217         /* For these modes we remember the original IV for later use */
 218         if (!ossl_assert(EVP_CIPHER_CTX_iv_length(ctx) <= (int)sizeof(ctx->oiv))) {
 219             EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 220             return 0;
 221         }
 222         if (iv != NULL)
 223             memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 224     }
 225
 226     if (enc) {
 227         if (ctx->cipher->einit == NULL) {
 228             EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 229             return 0;
 230         }
 231
 232         return ctx->cipher->einit(ctx->provctx, key, iv);
 233     }
 234
 235     if (ctx->cipher->dinit == NULL) {
 236         EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 237         return 0;
 238     }
 239
 240     return ctx->cipher->dinit(ctx->provctx, key, iv);
 241
 242     /* TODO(3.0): Remove legacy code below */
 243  legacy:
 244
 245     if (cipher != NULL) {
 246         /*
 247          * Ensure a context left lying around from last time is cleared (we
 248          * previously attempted to avoid this if the same ENGINE and
 249          * EVP_CIPHER could be used).
 250          */
 251         if (ctx->cipher) {
 252             unsigned long flags = ctx->flags;
 253             EVP_CIPHER_CTX_reset(ctx);
 254             /* Restore encrypt and flags */
 255             ctx->encrypt = enc;
 256             ctx->flags = flags;
 257         }
 258 #ifndef OPENSSL_NO_ENGINE
 259         if (impl != NULL) {
 260             if (!ENGINE_init(impl)) {
 261                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 262                 return 0;
 263             }
 264         } else {
 265             impl = tmpimpl;
 266         }
 267         if (impl != NULL) {
 268             /* There's an ENGINE for this job ... (apparently) */
 269             const EVP_CIPHER *c = ENGINE_get_cipher(impl, cipher->nid);
 270
 271             if (c == NULL) {
 272                 /*
 273                  * One positive side-effect of US's export control history,
 274                  * is that we should at least be able to avoid using US
 275                  * misspellings of "initialisation"?
 276                  */
 277                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 278                 return 0;
 279             }
 280             /* We'll use the ENGINE's private cipher definition */
 281             cipher = c;
 282             /*
 283              * Store the ENGINE functional reference so we know 'cipher' came
 284              * from an ENGINE and we need to release it when done.
 285              */
 286             ctx->engine = impl;
 287         } else {
 288             ctx->engine = NULL;
 289         }
 290 #endif
 291
 292         ctx->cipher = cipher;
 293         if (ctx->cipher->ctx_size) {
 294             ctx->cipher_data = OPENSSL_zalloc(ctx->cipher->ctx_size);
 295             if (ctx->cipher_data == NULL) {
 296                 ctx->cipher = NULL;
 297                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, ERR_R_MALLOC_FAILURE);
 298                 return 0;
 299             }
 300         } else {
 301             ctx->cipher_data = NULL;
 302         }
 303         ctx->key_len = cipher->key_len;
 304         /* Preserve wrap enable flag, zero everything else */
 305         ctx->flags &= EVP_CIPHER_CTX_FLAG_WRAP_ALLOW;
 306         if (ctx->cipher->flags & EVP_CIPH_CTRL_INIT) {
 307             if (!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_INIT, 0, NULL)) {
 308                 ctx->cipher = NULL;
 309                 EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);
 310                 return 0;
 311             }
 312         }
 313     }
 314 #ifndef OPENSSL_NO_ENGINE
 315  skip_to_init:
 316 #endif
 317     /* we assume block size is a power of 2 in *cryptUpdate */
 318     OPENSSL_assert(ctx->cipher->block_size == 1
 319                    || ctx->cipher->block_size == 8
 320                    || ctx->cipher->block_size == 16);
 321
 322     if (!(ctx->flags & EVP_CIPHER_CTX_FLAG_WRAP_ALLOW)
 323         && EVP_CIPHER_CTX_mode(ctx) == EVP_CIPH_WRAP_MODE) {
 324         EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_WRAP_MODE_NOT_ALLOWED);
 325         return 0;
 326     }
 327
 328     if (!(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ctx)) & EVP_CIPH_CUSTOM_IV)) {
 329         switch (EVP_CIPHER_CTX_mode(ctx)) {
 330
 331         case EVP_CIPH_STREAM_CIPHER:
 332         case EVP_CIPH_ECB_MODE:
 333             break;
 334
 335         case EVP_CIPH_CFB_MODE:
 336         case EVP_CIPH_OFB_MODE:
 337
 338             ctx->num = 0;
 339             /* fall-through */
 340
 341         case EVP_CIPH_CBC_MODE:
 342
 343             OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) <=
 344                            (int)sizeof(ctx->iv));
 345             if (iv)
 346                 memcpy(ctx->oiv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 347             memcpy(ctx->iv, ctx->oiv, EVP_CIPHER_CTX_iv_length(ctx));
 348             break;
 349
 350         case EVP_CIPH_CTR_MODE:
 351             ctx->num = 0;
 352             /* Don't reuse IV for CTR mode */
 353             if (iv)
 354                 memcpy(ctx->iv, iv, EVP_CIPHER_CTX_iv_length(ctx));
 355             break;
 356
 357         default:
 358             return 0;
 359         }
 360     }
 361
 362     if (key || (ctx->cipher->flags & EVP_CIPH_ALWAYS_CALL_INIT)) {
 363         if (!ctx->cipher->init(ctx, key, iv, enc))
 364             return 0;
 365     }
 366     ctx->buf_len = 0;
 367     ctx->final_used = 0;
 368     ctx->block_mask = ctx->cipher->block_size - 1;
 369     return 1;
 370 }
 371
 372 int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 373                      const unsigned char *in, int inl)
 374 {
 375     if (ctx->encrypt)
 376         return EVP_EncryptUpdate(ctx, out, outl, in, inl);
 377     else
 378         return EVP_DecryptUpdate(ctx, out, outl, in, inl);
 379 }
 380
 381 int EVP_CipherFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 382 {
 383     if (ctx->encrypt)
 384         return EVP_EncryptFinal_ex(ctx, out, outl);
 385     else
 386         return EVP_DecryptFinal_ex(ctx, out, outl);
 387 }
 388
 389 int EVP_CipherFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 390 {
 391     if (ctx->encrypt)
 392         return EVP_EncryptFinal(ctx, out, outl);
 393     else
 394         return EVP_DecryptFinal(ctx, out, outl);
 395 }
 396
 397 int EVP_EncryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 398                     const unsigned char *key, const unsigned char *iv)
 399 {
 400     return EVP_CipherInit(ctx, cipher, key, iv, 1);
 401 }
 402
 403 int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 404                        ENGINE *impl, const unsigned char *key,
 405                        const unsigned char *iv)
 406 {
 407     return EVP_CipherInit_ex(ctx, cipher, impl, key, iv, 1);
 408 }
 409
 410 int EVP_DecryptInit(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 411                     const unsigned char *key, const unsigned char *iv)
 412 {
 413     return EVP_CipherInit(ctx, cipher, key, iv, 0);
 414 }
 415
 416 int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 417                        ENGINE *impl, const unsigned char *key,
 418                        const unsigned char *iv)
 419 {
 420     return EVP_CipherInit_ex(ctx, cipher, impl, key, iv, 0);
 421 }
 422
 423 /*
 424  * According to the letter of standard difference between pointers
 425  * is specified to be valid only within same object. This makes
 426  * it formally challenging to determine if input and output buffers
 427  * are not partially overlapping with standard pointer arithmetic.
 428  */
 429 #ifdef PTRDIFF_T
 430 # undef PTRDIFF_T
 431 #endif
 432 #if defined(OPENSSL_SYS_VMS) && __INITIAL_POINTER_SIZE==64
 433 /*
 434  * Then we have VMS that distinguishes itself by adhering to
 435  * sizeof(size_t)==4 even in 64-bit builds, which means that
 436  * difference between two pointers might be truncated to 32 bits.
 437  * In the context one can even wonder how comparison for
 438  * equality is implemented. To be on the safe side we adhere to
 439  * PTRDIFF_T even for comparison for equality.
 440  */
 441 # define PTRDIFF_T uint64_t
 442 #else
 443 # define PTRDIFF_T size_t
 444 #endif
 445
 446 int is_partially_overlapping(const void *ptr1, const void *ptr2, int len)
 447 {
 448     PTRDIFF_T diff = (PTRDIFF_T)ptr1-(PTRDIFF_T)ptr2;
 449     /*
 450      * Check for partially overlapping buffers. [Binary logical
 451      * operations are used instead of boolean to minimize number
 452      * of conditional branches.]
 453      */
 454     int overlapped = (len > 0) & (diff != 0) & ((diff < (PTRDIFF_T)len) |
 455                                                 (diff > (0 - (PTRDIFF_T)len)));
 456
 457     return overlapped;
 458 }
 459
 460 static int evp_EncryptDecryptUpdate(EVP_CIPHER_CTX *ctx,
 461                                     unsigned char *out, int *outl,
 462                                     const unsigned char *in, int inl)
 463 {
 464     int i, j, bl, cmpl = inl;
 465
 466     if (EVP_CIPHER_CTX_test_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS))
 467         cmpl = (cmpl + 7) / 8;
 468
 469     bl = ctx->cipher->block_size;
 470
 471     if (inl <= 0) {
 472         *outl = 0;
 473         return inl == 0;
 474     }
 475
 476     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 477         /* If block size > 1 then the cipher will have to do this check */
 478         if (bl == 1 && is_partially_overlapping(out, in, cmpl)) {
 479             EVPerr(EVP_F_EVP_ENCRYPTDECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 480             return 0;
 481         }
 482
 483         i = ctx->cipher->do_cipher(ctx, out, in, inl);
 484         if (i < 0)
 485             return 0;
 486         else
 487             *outl = i;
 488         return 1;
 489     }
 490
 491     if (is_partially_overlapping(out + ctx->buf_len, in, cmpl)) {
 492         EVPerr(EVP_F_EVP_ENCRYPTDECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 493         return 0;
 494     }
 495
 496     if (ctx->buf_len == 0 && (inl & (ctx->block_mask)) == 0) {
 497         if (ctx->cipher->do_cipher(ctx, out, in, inl)) {
 498             *outl = inl;
 499             return 1;
 500         } else {
 501             *outl = 0;
 502             return 0;
 503         }
 504     }
 505     i = ctx->buf_len;
 506     OPENSSL_assert(bl <= (int)sizeof(ctx->buf));
 507     if (i != 0) {
 508         if (bl - i > inl) {
 509             memcpy(&(ctx->buf[i]), in, inl);
 510             ctx->buf_len += inl;
 511             *outl = 0;
 512             return 1;
 513         } else {
 514             j = bl - i;
 515             memcpy(&(ctx->buf[i]), in, j);
 516             inl -= j;
 517             in += j;
 518             if (!ctx->cipher->do_cipher(ctx, out, ctx->buf, bl))
 519                 return 0;
 520             out += bl;
 521             *outl = bl;
 522         }
 523     } else
 524         *outl = 0;
 525     i = inl & (bl - 1);
 526     inl -= i;
 527     if (inl > 0) {
 528         if (!ctx->cipher->do_cipher(ctx, out, in, inl))
 529             return 0;
 530         *outl += inl;
 531     }
 532
 533     if (i != 0)
 534         memcpy(ctx->buf, &(in[inl]), i);
 535     ctx->buf_len = i;
 536     return 1;
 537 }
 538
 539
 540 int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 541                       const unsigned char *in, int inl)
 542 {
 543     int ret;
 544     size_t soutl;
 545
 546     /* Prevent accidental use of decryption context when encrypting */
 547     if (!ctx->encrypt) {
 548         EVPerr(EVP_F_EVP_ENCRYPTUPDATE, EVP_R_INVALID_OPERATION);
 549         return 0;
 550     }
 551
 552     if (ctx->cipher == NULL || ctx->cipher->prov == NULL)
 553         goto legacy;
 554
 555     if (ctx->cipher->cupdate == NULL) {
 556         EVPerr(EVP_F_EVP_ENCRYPTUPDATE, EVP_R_UPDATE_ERROR);
 557         return 0;
 558     }
 559     ret = ctx->cipher->cupdate(ctx->provctx, out, &soutl, in, (size_t)inl);
 560
 561     if (soutl > INT_MAX) {
 562         EVPerr(EVP_F_EVP_ENCRYPTUPDATE, EVP_R_UPDATE_ERROR);
 563         return 0;
 564     }
 565     *outl = soutl;
 566     return ret;
 567
 568     /* TODO(3.0): Remove legacy code below */
 569  legacy:
 570
 571     return evp_EncryptDecryptUpdate(ctx, out, outl, in, inl);
 572 }
 573
 574 int EVP_EncryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 575 {
 576     int ret;
 577     ret = EVP_EncryptFinal_ex(ctx, out, outl);
 578     return ret;
 579 }
 580
 581 int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 582 {
 583     int n, ret;
 584     unsigned int i, b, bl;
 585     size_t soutl;
 586
 587     /* Prevent accidental use of decryption context when encrypting */
 588     if (!ctx->encrypt) {
 589         EVPerr(EVP_F_EVP_ENCRYPTFINAL_EX, EVP_R_INVALID_OPERATION);
 590         return 0;
 591     }
 592
 593     if (ctx->cipher == NULL || ctx->cipher->prov == NULL)
 594         goto legacy;
 595
 596     if (ctx->cipher->cfinal == NULL) {
 597         EVPerr(EVP_F_EVP_ENCRYPTFINAL_EX, EVP_R_FINAL_ERROR);
 598         return 0;
 599     }
 600
 601     ret = ctx->cipher->cfinal(ctx->provctx, out, &soutl);
 602
 603     if (soutl > INT_MAX) {
 604         EVPerr(EVP_F_EVP_ENCRYPTFINAL_EX, EVP_R_FINAL_ERROR);
 605         return 0;
 606     }
 607     *outl = soutl;
 608
 609     return ret;
 610
 611     /* TODO(3.0): Remove legacy code below */
 612  legacy:
 613
 614     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 615         ret = ctx->cipher->do_cipher(ctx, out, NULL, 0);
 616         if (ret < 0)
 617             return 0;
 618         else
 619             *outl = ret;
 620         return 1;
 621     }
 622
 623     b = ctx->cipher->block_size;
 624     OPENSSL_assert(b <= sizeof(ctx->buf));
 625     if (b == 1) {
 626         *outl = 0;
 627         return 1;
 628     }
 629     bl = ctx->buf_len;
 630     if (ctx->flags & EVP_CIPH_NO_PADDING) {
 631         if (bl) {
 632             EVPerr(EVP_F_EVP_ENCRYPTFINAL_EX,
 633                    EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
 634             return 0;
 635         }
 636         *outl = 0;
 637         return 1;
 638     }
 639
 640     n = b - bl;
 641     for (i = bl; i < b; i++)
 642         ctx->buf[i] = n;
 643     ret = ctx->cipher->do_cipher(ctx, out, ctx->buf, b);
 644
 645     if (ret)
 646         *outl = b;
 647
 648     return ret;
 649 }
 650
 651 int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
 652                       const unsigned char *in, int inl)
 653 {
 654     int fix_len, cmpl = inl, ret;
 655     unsigned int b;
 656     size_t soutl;
 657
 658     /* Prevent accidental use of encryption context when decrypting */
 659     if (ctx->encrypt) {
 660         EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_INVALID_OPERATION);
 661         return 0;
 662     }
 663
 664     if (ctx->cipher == NULL || ctx->cipher->prov == NULL)
 665         goto legacy;
 666
 667     if (ctx->cipher->cupdate == NULL) {
 668         EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_UPDATE_ERROR);
 669         return 0;
 670     }
 671     ret = ctx->cipher->cupdate(ctx->provctx, out, &soutl, in, (size_t)inl);
 672
 673     if (ret) {
 674         if (soutl > INT_MAX) {
 675             EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_UPDATE_ERROR);
 676             return 0;
 677         }
 678         *outl = soutl;
 679     }
 680
 681     return ret;
 682
 683     /* TODO(3.0): Remove legacy code below */
 684  legacy:
 685
 686     b = ctx->cipher->block_size;
 687
 688     if (EVP_CIPHER_CTX_test_flags(ctx, EVP_CIPH_FLAG_LENGTH_BITS))
 689         cmpl = (cmpl + 7) / 8;
 690
 691     if (inl <= 0) {
 692         *outl = 0;
 693         return inl == 0;
 694     }
 695
 696     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 697         if (b == 1 && is_partially_overlapping(out, in, cmpl)) {
 698             EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 699             return 0;
 700         }
 701
 702         fix_len = ctx->cipher->do_cipher(ctx, out, in, inl);
 703         if (fix_len < 0) {
 704             *outl = 0;
 705             return 0;
 706         } else
 707             *outl = fix_len;
 708         return 1;
 709     }
 710
 711     if (ctx->flags & EVP_CIPH_NO_PADDING)
 712         return evp_EncryptDecryptUpdate(ctx, out, outl, in, inl);
 713
 714     OPENSSL_assert(b <= sizeof(ctx->final));
 715
 716     if (ctx->final_used) {
 717         /* see comment about PTRDIFF_T comparison above */
 718         if (((PTRDIFF_T)out == (PTRDIFF_T)in)
 719             || is_partially_overlapping(out, in, b)) {
 720             EVPerr(EVP_F_EVP_DECRYPTUPDATE, EVP_R_PARTIALLY_OVERLAPPING);
 721             return 0;
 722         }
 723         memcpy(out, ctx->final, b);
 724         out += b;
 725         fix_len = 1;
 726     } else
 727         fix_len = 0;
 728
 729     if (!evp_EncryptDecryptUpdate(ctx, out, outl, in, inl))
 730         return 0;
 731
 732     /*
 733      * if we have 'decrypted' a multiple of block size, make sure we have a
 734      * copy of this last block
 735      */
 736     if (b > 1 && !ctx->buf_len) {
 737         *outl -= b;
 738         ctx->final_used = 1;
 739         memcpy(ctx->final, &out[*outl], b);
 740     } else
 741         ctx->final_used = 0;
 742
 743     if (fix_len)
 744         *outl += b;
 745
 746     return 1;
 747 }
 748
 749 int EVP_DecryptFinal(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 750 {
 751     int ret;
 752     ret = EVP_DecryptFinal_ex(ctx, out, outl);
 753     return ret;
 754 }
 755
 756 int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl)
 757 {
 758     int i, n;
 759     unsigned int b;
 760     size_t soutl;
 761     int ret;
 762
 763     /* Prevent accidental use of encryption context when decrypting */
 764     if (ctx->encrypt) {
 765         EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_INVALID_OPERATION);
 766         return 0;
 767     }
 768
 769     if (ctx->cipher == NULL || ctx->cipher->prov == NULL)
 770         goto legacy;
 771
 772     if (ctx->cipher->cfinal == NULL) {
 773         EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_FINAL_ERROR);
 774         return 0;
 775     }
 776
 777     ret = ctx->cipher->cfinal(ctx->provctx, out, &soutl);
 778
 779     if (ret) {
 780         if (soutl > INT_MAX) {
 781             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_FINAL_ERROR);
 782             return 0;
 783         }
 784         *outl = soutl;
 785     }
 786
 787     return ret;
 788
 789     /* TODO(3.0): Remove legacy code below */
 790  legacy:
 791
 792     *outl = 0;
 793
 794     if (ctx->cipher->flags & EVP_CIPH_FLAG_CUSTOM_CIPHER) {
 795         i = ctx->cipher->do_cipher(ctx, out, NULL, 0);
 796         if (i < 0)
 797             return 0;
 798         else
 799             *outl = i;
 800         return 1;
 801     }
 802
 803     b = ctx->cipher->block_size;
 804     if (ctx->flags & EVP_CIPH_NO_PADDING) {
 805         if (ctx->buf_len) {
 806             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX,
 807                    EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH);
 808             return 0;
 809         }
 810         *outl = 0;
 811         return 1;
 812     }
 813     if (b > 1) {
 814         if (ctx->buf_len || !ctx->final_used) {
 815             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_WRONG_FINAL_BLOCK_LENGTH);
 816             return 0;
 817         }
 818         OPENSSL_assert(b <= sizeof(ctx->final));
 819
 820         /*
 821          * The following assumes that the ciphertext has been authenticated.
 822          * Otherwise it provides a padding oracle.
 823          */
 824         n = ctx->final[b - 1];
 825         if (n == 0 || n > (int)b) {
 826             EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_BAD_DECRYPT);
 827             return 0;
 828         }
 829         for (i = 0; i < n; i++) {
 830             if (ctx->final[--b] != n) {
 831                 EVPerr(EVP_F_EVP_DECRYPTFINAL_EX, EVP_R_BAD_DECRYPT);
 832                 return 0;
 833             }
 834         }
 835         n = ctx->cipher->block_size - n;
 836         for (i = 0; i < n; i++)
 837             out[i] = ctx->final[i];
 838         *outl = n;
 839     } else
 840         *outl = 0;
 841     return 1;
 842 }
 843
 844 int EVP_CIPHER_CTX_set_key_length(EVP_CIPHER_CTX *c, int keylen)
 845 {
 846     if (c->cipher->flags & EVP_CIPH_CUSTOM_KEY_LENGTH)
 847         return EVP_CIPHER_CTX_ctrl(c, EVP_CTRL_SET_KEY_LENGTH, keylen, NULL);
 848     if (EVP_CIPHER_CTX_key_length(c) == keylen)
 849         return 1;
 850     if ((keylen > 0) && (c->cipher->flags & EVP_CIPH_VARIABLE_LENGTH)) {
 851         c->key_len = keylen;
 852         return 1;
 853     }
 854     EVPerr(EVP_F_EVP_CIPHER_CTX_SET_KEY_LENGTH, EVP_R_INVALID_KEY_LENGTH);
 855     return 0;
 856 }
 857
 858 int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *ctx, int pad)
 859 {
 860     if (pad)
 861         ctx->flags &= ~EVP_CIPH_NO_PADDING;
 862     else
 863         ctx->flags |= EVP_CIPH_NO_PADDING;
 864
 865     if (ctx->cipher != NULL && ctx->cipher->prov != NULL) {
 866         OSSL_PARAM params[] = {
 867             OSSL_PARAM_int(OSSL_CIPHER_PARAM_PADDING, NULL),
 868             OSSL_PARAM_END
 869         };
 870
 871         params[0].data = &pad;
 872
 873         if (ctx->cipher->ctx_set_params == NULL) {
 874             EVPerr(EVP_F_EVP_CIPHER_CTX_SET_PADDING, EVP_R_CTRL_NOT_IMPLEMENTED);
 875             return 0;
 876         }
 877
 878         if (!ctx->cipher->ctx_set_params(ctx->provctx, params))
 879             return 0;
 880     }
 881
 882     return 1;
 883 }
 884
 885 int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr)
 886 {
 887     int ret;
 888
 889     if (!ctx->cipher) {
 890         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_NO_CIPHER_SET);
 891         return 0;
 892     }
 893
 894     if (!ctx->cipher->ctrl) {
 895         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL, EVP_R_CTRL_NOT_IMPLEMENTED);
 896         return 0;
 897     }
 898
 899     ret = ctx->cipher->ctrl(ctx, type, arg, ptr);
 900     if (ret == -1) {
 901         EVPerr(EVP_F_EVP_CIPHER_CTX_CTRL,
 902                EVP_R_CTRL_OPERATION_NOT_IMPLEMENTED);
 903         return 0;
 904     }
 905     return ret;
 906 }
 907
 908 int EVP_CIPHER_CTX_rand_key(EVP_CIPHER_CTX *ctx, unsigned char *key)
 909 {
 910     if (ctx->cipher->flags & EVP_CIPH_RAND_KEY)
 911         return EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_RAND_KEY, 0, key);
 912     if (RAND_priv_bytes(key, ctx->key_len) <= 0)
 913         return 0;
 914     return 1;
 915 }
 916
 917 int EVP_CIPHER_CTX_copy(EVP_CIPHER_CTX *out, const EVP_CIPHER_CTX *in)
 918 {
 919     if ((in == NULL) || (in->cipher == NULL)) {
 920         EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, EVP_R_INPUT_NOT_INITIALIZED);
 921         return 0;
 922     }
 923
 924     if (in->cipher->prov == NULL)
 925         goto legacy;
 926
 927     if (in->cipher->dupctx == NULL) {
 928         EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, EVP_R_NOT_ABLE_TO_COPY_CTX);
 929         return 0;
 930     }
 931
 932     EVP_CIPHER_CTX_reset(out);
 933
 934     *out = *in;
 935     out->provctx = NULL;
 936
 937     if (in->fetched_cipher != NULL && !EVP_CIPHER_upref(in->fetched_cipher)) {
 938         out->fetched_cipher = NULL;
 939         return 0;
 940     }
 941
 942     out->provctx = in->cipher->dupctx(in->provctx);
 943     if (out->provctx == NULL) {
 944         EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, EVP_R_NOT_ABLE_TO_COPY_CTX);
 945         return 0;
 946     }
 947
 948     return 1;
 949
 950     /* TODO(3.0): Remove legacy code below */
 951  legacy:
 952
 953 #ifndef OPENSSL_NO_ENGINE
 954     /* Make sure it's safe to copy a cipher context using an ENGINE */
 955     if (in->engine && !ENGINE_init(in->engine)) {
 956         EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, ERR_R_ENGINE_LIB);
 957         return 0;
 958     }
 959 #endif
 960
 961     EVP_CIPHER_CTX_reset(out);
 962     memcpy(out, in, sizeof(*out));
 963
 964     if (in->cipher_data && in->cipher->ctx_size) {
 965         out->cipher_data = OPENSSL_malloc(in->cipher->ctx_size);
 966         if (out->cipher_data == NULL) {
 967             out->cipher = NULL;
 968             EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, ERR_R_MALLOC_FAILURE);
 969             return 0;
 970         }
 971         memcpy(out->cipher_data, in->cipher_data, in->cipher->ctx_size);
 972     }
 973
 974     if (in->cipher->flags & EVP_CIPH_CUSTOM_COPY)
 975         if (!in->cipher->ctrl((EVP_CIPHER_CTX *)in, EVP_CTRL_COPY, 0, out)) {
 976             out->cipher = NULL;
 977             EVPerr(EVP_F_EVP_CIPHER_CTX_COPY, EVP_R_INITIALIZATION_ERROR);
 978             return 0;
 979         }
 980     return 1;
 981 }
 982
 983 static void *evp_cipher_from_dispatch(int nid, const OSSL_DISPATCH *fns,
 984                                       OSSL_PROVIDER *prov)
 985 {
 986     EVP_CIPHER *cipher = NULL;
 987     int fnciphcnt = 0, fnctxcnt = 0;
 988
 989     if ((cipher = EVP_CIPHER_meth_new(nid, 0, 0)) == NULL)
 990         return NULL;
 991
 992     for (; fns->function_id != 0; fns++) {
 993         switch (fns->function_id) {
 994         case OSSL_FUNC_CIPHER_NEWCTX:
 995             if (cipher->newctx != NULL)
 996                 break;
 997             cipher->newctx = OSSL_get_OP_cipher_newctx(fns);
 998             fnctxcnt++;
 999             break;
1000         case OSSL_FUNC_CIPHER_ENCRYPT_INIT:
1001             if (cipher->einit != NULL)
1002                 break;
1003             cipher->einit = OSSL_get_OP_cipher_encrypt_init(fns);
1004             fnciphcnt++;
1005             break;
1006         case OSSL_FUNC_CIPHER_DECRYPT_INIT:
1007             if (cipher->dinit != NULL)
1008                 break;
1009             cipher->dinit = OSSL_get_OP_cipher_decrypt_init(fns);
1010             fnciphcnt++;
1011             break;
1012         case OSSL_FUNC_CIPHER_UPDATE:
1013             if (cipher->cupdate != NULL)
1014                 break;
1015             cipher->cupdate = OSSL_get_OP_cipher_update(fns);
1016             fnciphcnt++;
1017             break;
1018         case OSSL_FUNC_CIPHER_FINAL:
1019             if (cipher->cfinal != NULL)
1020                 break;
1021             cipher->cfinal = OSSL_get_OP_cipher_final(fns);
1022             fnciphcnt++;
1023             break;
1024         case OSSL_FUNC_CIPHER_CIPHER:
1025             if (cipher->ccipher != NULL)
1026                 break;
1027             cipher->ccipher = OSSL_get_OP_cipher_cipher(fns);
1028             break;
1029         case OSSL_FUNC_CIPHER_FREECTX:
1030             if (cipher->freectx != NULL)
1031                 break;
1032             cipher->freectx = OSSL_get_OP_cipher_freectx(fns);
1033             fnctxcnt++;
1034             break;
1035         case OSSL_FUNC_CIPHER_DUPCTX:
1036             if (cipher->dupctx != NULL)
1037                 break;
1038             cipher->dupctx = OSSL_get_OP_cipher_dupctx(fns);
1039             break;
1040         case OSSL_FUNC_CIPHER_KEY_LENGTH:
1041             if (cipher->key_length != NULL)
1042                 break;
1043             cipher->key_length = OSSL_get_OP_cipher_key_length(fns);
1044             break;
1045         case OSSL_FUNC_CIPHER_IV_LENGTH:
1046             if (cipher->iv_length != NULL)
1047                 break;
1048             cipher->iv_length = OSSL_get_OP_cipher_iv_length(fns);
1049             break;
1050         case OSSL_FUNC_CIPHER_BLOCK_SIZE:
1051             if (cipher->blocksize != NULL)
1052                 break;
1053             cipher->blocksize = OSSL_get_OP_cipher_block_size(fns);
1054             break;
1055         case OSSL_FUNC_CIPHER_GET_PARAMS:
1056             if (cipher->get_params != NULL)
1057                 break;
1058             cipher->get_params = OSSL_get_OP_cipher_get_params(fns);
1059             break;
1060         case OSSL_FUNC_CIPHER_CTX_GET_PARAMS:
1061             if (cipher->ctx_get_params != NULL)
1062                 break;
1063             cipher->ctx_get_params = OSSL_get_OP_cipher_ctx_get_params(fns);
1064             break;
1065         case OSSL_FUNC_CIPHER_CTX_SET_PARAMS:
1066             if (cipher->ctx_set_params != NULL)
1067                 break;
1068             cipher->ctx_set_params = OSSL_get_OP_cipher_ctx_set_params(fns);
1069             break;
1070         }
1071     }
1072     if ((fnciphcnt != 0 && fnciphcnt != 3 && fnciphcnt != 4)
1073             || (fnciphcnt == 0 && cipher->ccipher == NULL)
1074             || fnctxcnt != 2) {
1075         /*
1076          * In order to be a consistent set of functions we must have at least
1077          * a complete set of "encrypt" functions, or a complete set of "decrypt"
1078          * functions, or a single "cipher" function. In all cases we need a
1079          * complete set of context management functions
1080          */
1081         EVP_CIPHER_meth_free(cipher);
1082         EVPerr(EVP_F_EVP_CIPHER_FROM_DISPATCH, EVP_R_INVALID_PROVIDER_FUNCTIONS);
1083         return NULL;
1084     }
1085     cipher->prov = prov;
1086     if (prov != NULL)
1087         ossl_provider_upref(prov);
1088
1089     return cipher;
1090 }
1091
1092 static int evp_cipher_upref(void *cipher)
1093 {
1094     return EVP_CIPHER_upref(cipher);
1095 }
1096
1097 static void evp_cipher_free(void *cipher)
1098 {
1099     EVP_CIPHER_meth_free(cipher);
1100 }
1101
1102 static int evp_cipher_nid(void *vcipher)
1103 {
1104     EVP_CIPHER *cipher = vcipher;
1105
1106     return cipher->nid;
1107 }
1108
1109 EVP_CIPHER *EVP_CIPHER_fetch(OPENSSL_CTX *ctx, const char *algorithm,
1110                              const char *properties)
1111 {
1112     return evp_generic_fetch(ctx, OSSL_OP_CIPHER, algorithm, properties,
1113                              evp_cipher_from_dispatch, evp_cipher_upref,
1114                              evp_cipher_free, evp_cipher_nid);
1115 }