lib/libcrypto/evp/bio_enc.c

   1 /* $OpenBSD: bio_enc.c,v 1.19 2015/09/10 15:56:25 jsing Exp $ */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58
  59 #include <errno.h>
  60 #include <stdio.h>
  61 #include <string.h>
  62
  63 #include <openssl/buffer.h>
  64 #include <openssl/evp.h>
  65
  66 static int enc_write(BIO *h, const char *buf, int num);
  67 static int enc_read(BIO *h, char *buf, int size);
  68 /*static int enc_puts(BIO *h, const char *str); */
  69 /*static int enc_gets(BIO *h, char *str, int size); */
  70 static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
  71 static int enc_new(BIO *h);
  72 static int enc_free(BIO *data);
  73 static long enc_callback_ctrl(BIO *h, int cmd, bio_info_cb *fps);
  74 #define ENC_BLOCK_SIZE  (1024*4)
  75 #define BUF_OFFSET      (EVP_MAX_BLOCK_LENGTH*2)
  76
  77 typedef struct enc_struct {
  78         int buf_len;
  79         int buf_off;
  80         int cont;               /* <= 0 when finished */
  81         int finished;
  82         int ok;                 /* bad decrypt */
  83         EVP_CIPHER_CTX cipher;
  84         /* buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate
  85          * can return up to a block more data than is presented to it
  86          */
  87         char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2];
  88 } BIO_ENC_CTX;
  89
  90 static BIO_METHOD methods_enc = {
  91         .type = BIO_TYPE_CIPHER,
  92         .name = "cipher",
  93         .bwrite = enc_write,
  94         .bread = enc_read,
  95         .ctrl = enc_ctrl,
  96         .create = enc_new,
  97         .destroy = enc_free,
  98         .callback_ctrl = enc_callback_ctrl
  99 };
 100
 101 BIO_METHOD *
 102 BIO_f_cipher(void)
 103 {
 104         return (&methods_enc);
 105 }
 106
 107 static int
 108 enc_new(BIO *bi)
 109 {
 110         BIO_ENC_CTX *ctx;
 111
 112         ctx = malloc(sizeof(BIO_ENC_CTX));
 113         if (ctx == NULL)
 114                 return (0);
 115         EVP_CIPHER_CTX_init(&ctx->cipher);
 116
 117         ctx->buf_len = 0;
 118         ctx->buf_off = 0;
 119         ctx->cont = 1;
 120         ctx->finished = 0;
 121         ctx->ok = 1;
 122
 123         bi->init = 0;
 124         bi->ptr = (char *)ctx;
 125         bi->flags = 0;
 126         return (1);
 127 }
 128
 129 static int
 130 enc_free(BIO *a)
 131 {
 132         BIO_ENC_CTX *b;
 133
 134         if (a == NULL)
 135                 return (0);
 136         b = (BIO_ENC_CTX *)a->ptr;
 137         EVP_CIPHER_CTX_cleanup(&(b->cipher));
 138         explicit_bzero(a->ptr, sizeof(BIO_ENC_CTX));
 139         free(a->ptr);
 140         a->ptr = NULL;
 141         a->init = 0;
 142         a->flags = 0;
 143         return (1);
 144 }
 145
 146 static int
 147 enc_read(BIO *b, char *out, int outl)
 148 {
 149         int ret = 0, i;
 150         BIO_ENC_CTX *ctx;
 151
 152         if (out == NULL)
 153                 return (0);
 154         ctx = (BIO_ENC_CTX *)b->ptr;
 155
 156         if ((ctx == NULL) || (b->next_bio == NULL))
 157                 return (0);
 158
 159         /* First check if there are bytes decoded/encoded */
 160         if (ctx->buf_len > 0) {
 161                 i = ctx->buf_len - ctx->buf_off;
 162                 if (i > outl)
 163                         i = outl;
 164                 memcpy(out, &(ctx->buf[ctx->buf_off]), i);
 165                 ret = i;
 166                 out += i;
 167                 outl -= i;
 168                 ctx->buf_off += i;
 169                 if (ctx->buf_len == ctx->buf_off) {
 170                         ctx->buf_len = 0;
 171                         ctx->buf_off = 0;
 172                 }
 173         }
 174
 175         /* At this point, we have room of outl bytes and an empty
 176          * buffer, so we should read in some more. */
 177
 178         while (outl > 0) {
 179                 if (ctx->cont <= 0)
 180                         break;
 181
 182                 /* read in at IV offset, read the EVP_Cipher
 183                  * documentation about why */
 184                 i = BIO_read(b->next_bio, &(ctx->buf[BUF_OFFSET]), ENC_BLOCK_SIZE);
 185
 186                 if (i <= 0) {
 187                         /* Should be continue next time we are called? */
 188                         if (!BIO_should_retry(b->next_bio)) {
 189                                 ctx->cont = i;
 190                                 i = EVP_CipherFinal_ex(&(ctx->cipher),
 191                                     (unsigned char *)ctx->buf,
 192                                     &(ctx->buf_len));
 193                                 ctx->ok = i;
 194                                 ctx->buf_off = 0;
 195                         } else {
 196                                 ret = (ret == 0) ? i : ret;
 197                                 break;
 198                         }
 199                 } else {
 200                         EVP_CipherUpdate(&(ctx->cipher),
 201                             (unsigned char *)ctx->buf, &ctx->buf_len,
 202                             (unsigned char *)&(ctx->buf[BUF_OFFSET]), i);
 203                         ctx->cont = 1;
 204                         /* Note: it is possible for EVP_CipherUpdate to
 205                          * decrypt zero bytes because this is or looks like
 206                          * the final block: if this happens we should retry
 207                          * and either read more data or decrypt the final
 208                          * block
 209                          */
 210                         if (ctx->buf_len == 0)
 211                                 continue;
 212                 }
 213
 214                 if (ctx->buf_len <= outl)
 215                         i = ctx->buf_len;
 216                 else
 217                         i = outl;
 218                 if (i <= 0)
 219                         break;
 220                 memcpy(out, ctx->buf, i);
 221                 ret += i;
 222                 ctx->buf_off = i;
 223                 outl -= i;
 224                 out += i;
 225         }
 226
 227         BIO_clear_retry_flags(b);
 228         BIO_copy_next_retry(b);
 229         return ((ret == 0) ? ctx->cont : ret);
 230 }
 231
 232 static int
 233 enc_write(BIO *b, const char *in, int inl)
 234 {
 235         int ret = 0, n, i;
 236         BIO_ENC_CTX *ctx;
 237
 238         ctx = (BIO_ENC_CTX *)b->ptr;
 239         ret = inl;
 240
 241         BIO_clear_retry_flags(b);
 242         n = ctx->buf_len - ctx->buf_off;
 243         while (n > 0) {
 244                 i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
 245                 if (i <= 0) {
 246                         BIO_copy_next_retry(b);
 247                         return (i);
 248                 }
 249                 ctx->buf_off += i;
 250                 n -= i;
 251         }
 252         /* at this point all pending data has been written */
 253
 254         if ((in == NULL) || (inl <= 0))
 255                 return (0);
 256
 257         ctx->buf_off = 0;
 258         while (inl > 0) {
 259                 n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;
 260                 EVP_CipherUpdate(&(ctx->cipher),
 261                     (unsigned char *)ctx->buf, &ctx->buf_len,
 262                     (unsigned char *)in, n);
 263                 inl -= n;
 264                 in += n;
 265
 266                 ctx->buf_off = 0;
 267                 n = ctx->buf_len;
 268                 while (n > 0) {
 269                         i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
 270                         if (i <= 0) {
 271                                 BIO_copy_next_retry(b);
 272                                 return (ret == inl) ? i : ret - inl;
 273                         }
 274                         n -= i;
 275                         ctx->buf_off += i;
 276                 }
 277                 ctx->buf_len = 0;
 278                 ctx->buf_off = 0;
 279         }
 280         BIO_copy_next_retry(b);
 281         return (ret);
 282 }
 283
 284 static long
 285 enc_ctrl(BIO *b, int cmd, long num, void *ptr)
 286 {
 287         BIO *dbio;
 288         BIO_ENC_CTX *ctx, *dctx;
 289         long ret = 1;
 290         int i;
 291         EVP_CIPHER_CTX **c_ctx;
 292
 293         ctx = (BIO_ENC_CTX *)b->ptr;
 294
 295         switch (cmd) {
 296         case BIO_CTRL_RESET:
 297                 ctx->ok = 1;
 298                 ctx->finished = 0;
 299                 EVP_CipherInit_ex(&(ctx->cipher), NULL, NULL, NULL, NULL,
 300                     ctx->cipher.encrypt);
 301                 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 302                 break;
 303         case BIO_CTRL_EOF:      /* More to read */
 304                 if (ctx->cont <= 0)
 305                         ret = 1;
 306                 else
 307                         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 308                 break;
 309         case BIO_CTRL_WPENDING:
 310                 ret = ctx->buf_len - ctx->buf_off;
 311                 if (ret <= 0)
 312                         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 313                 break;
 314         case BIO_CTRL_PENDING: /* More to read in buffer */
 315                 ret = ctx->buf_len - ctx->buf_off;
 316                 if (ret <= 0)
 317                         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 318                 break;
 319         case BIO_CTRL_FLUSH:
 320                 /* do a final write */
 321 again:
 322                 while (ctx->buf_len != ctx->buf_off) {
 323                         i = enc_write(b, NULL, 0);
 324                         if (i < 0)
 325                                 return i;
 326                 }
 327
 328                 if (!ctx->finished) {
 329                         ctx->finished = 1;
 330                         ctx->buf_off = 0;
 331                         ret = EVP_CipherFinal_ex(&(ctx->cipher),
 332                             (unsigned char *)ctx->buf,
 333                             &(ctx->buf_len));
 334                         ctx->ok = (int)ret;
 335                         if (ret <= 0)
 336                                 break;
 337
 338                         /* push out the bytes */
 339                         goto again;
 340                 }
 341
 342                 /* Finally flush the underlying BIO */
 343                 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 344                 break;
 345         case BIO_C_GET_CIPHER_STATUS:
 346                 ret = (long)ctx->ok;
 347                 break;
 348         case BIO_C_DO_STATE_MACHINE:
 349                 BIO_clear_retry_flags(b);
 350                 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 351                 BIO_copy_next_retry(b);
 352                 break;
 353         case BIO_C_GET_CIPHER_CTX:
 354                 c_ctx = (EVP_CIPHER_CTX **)ptr;
 355                 (*c_ctx) = &(ctx->cipher);
 356                 b->init = 1;
 357                 break;
 358         case BIO_CTRL_DUP:
 359                 dbio = (BIO *)ptr;
 360                 dctx = (BIO_ENC_CTX *)dbio->ptr;
 361                 EVP_CIPHER_CTX_init(&dctx->cipher);
 362                 ret = EVP_CIPHER_CTX_copy(&dctx->cipher, &ctx->cipher);
 363                 if (ret)
 364                         dbio->init = 1;
 365                 break;
 366         default:
 367                 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 368                 break;
 369         }
 370         return (ret);
 371 }
 372
 373 static long
 374 enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
 375 {
 376         long ret = 1;
 377
 378         if (b->next_bio == NULL)
 379                 return (0);
 380         switch (cmd) {
 381         default:
 382                 ret = BIO_callback_ctrl(b->next_bio, cmd, fp);
 383                 break;
 384         }
 385         return (ret);
 386 }
 387
 388 /*
 389 void BIO_set_cipher_ctx(b,c)
 390 BIO *b;
 391 EVP_CIPHER_ctx *c;
 392         {
 393         if (b == NULL) return;
 394
 395         if ((b->callback != NULL) &&
 396                 (b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,0L) <= 0))
 397                 return;
 398
 399         b->init=1;
 400         ctx=(BIO_ENC_CTX *)b->ptr;
 401         memcpy(ctx->cipher,c,sizeof(EVP_CIPHER_CTX));
 402
 403         if (b->callback != NULL)
 404                 b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,1L);
 405         }
 406 */
 407
 408 void
 409 BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
 410     const unsigned char *i, int e)
 411 {
 412         BIO_ENC_CTX *ctx;
 413
 414         if (b == NULL)
 415                 return;
 416
 417         if ((b->callback != NULL) &&
 418             (b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 0L) <= 0))
 419                 return;
 420
 421         b->init = 1;
 422         ctx = (BIO_ENC_CTX *)b->ptr;
 423         EVP_CipherInit_ex(&(ctx->cipher), c, NULL, k, i, e);
 424
 425         if (b->callback != NULL)
 426                 b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);
 427 }