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