crypto/evp/bio_enc.c

   1 /* crypto/evp/bio_enc.c */
   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 <stdio.h>
  60 #include <errno.h>
  61 #include "cryptlib.h"
  62 #include <openssl/buffer.h>
  63 #include <openssl/evp.h>
  64
  65 static int enc_write(BIO *h, const char *buf, int num);
  66 static int enc_read(BIO *h, char *buf, int size);
  67 /*
  68  * static int enc_puts(BIO *h, const char *str);
  69  */
  70 /*
  71  * static int enc_gets(BIO *h, char *str, int size);
  72  */
  73 static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
  74 static int enc_new(BIO *h);
  75 static int enc_free(BIO *data);
  76 static long enc_callback_ctrl(BIO *h, int cmd, bio_info_cb *fps);
  77 #define ENC_BLOCK_SIZE  (1024*4)
  78 #define BUF_OFFSET      (EVP_MAX_BLOCK_LENGTH*2)
  79
  80 typedef struct enc_struct {
  81     int buf_len;
  82     int buf_off;
  83     int cont;                   /* <= 0 when finished */
  84     int finished;
  85     int ok;                     /* bad decrypt */
  86     EVP_CIPHER_CTX cipher;
  87     /*
  88      * buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate can return
  89      * up to a block more data than is presented to it
  90      */
  91     char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2];
  92 } BIO_ENC_CTX;
  93
  94 static BIO_METHOD methods_enc = {
  95     BIO_TYPE_CIPHER, "cipher",
  96     enc_write,
  97     enc_read,
  98     NULL,                       /* enc_puts, */
  99     NULL,                       /* enc_gets, */
 100     enc_ctrl,
 101     enc_new,
 102     enc_free,
 103     enc_callback_ctrl,
 104 };
 105
 106 BIO_METHOD *BIO_f_cipher(void)
 107 {
 108     return (&methods_enc);
 109 }
 110
 111 static int enc_new(BIO *bi)
 112 {
 113     BIO_ENC_CTX *ctx;
 114
 115     ctx = (BIO_ENC_CTX *)OPENSSL_malloc(sizeof(BIO_ENC_CTX));
 116     if (ctx == NULL)
 117         return (0);
 118     EVP_CIPHER_CTX_init(&ctx->cipher);
 119
 120     ctx->buf_len = 0;
 121     ctx->buf_off = 0;
 122     ctx->cont = 1;
 123     ctx->finished = 0;
 124     ctx->ok = 1;
 125
 126     bi->init = 0;
 127     bi->ptr = (char *)ctx;
 128     bi->flags = 0;
 129     return (1);
 130 }
 131
 132 static int enc_free(BIO *a)
 133 {
 134     BIO_ENC_CTX *b;
 135
 136     if (a == NULL)
 137         return (0);
 138     b = (BIO_ENC_CTX *)a->ptr;
 139     EVP_CIPHER_CTX_cleanup(&(b->cipher));
 140     OPENSSL_cleanse(a->ptr, sizeof(BIO_ENC_CTX));
 141     OPENSSL_free(a->ptr);
 142     a->ptr = NULL;
 143     a->init = 0;
 144     a->flags = 0;
 145     return (1);
 146 }
 147
 148 static int enc_read(BIO *b, char *out, int outl)
 149 {
 150     int ret = 0, i;
 151     BIO_ENC_CTX *ctx;
 152
 153     if (out == NULL)
 154         return (0);
 155     ctx = (BIO_ENC_CTX *)b->ptr;
 156
 157     if ((ctx == NULL) || (b->next_bio == NULL))
 158         return (0);
 159
 160     /* First check if there are bytes decoded/encoded */
 161     if (ctx->buf_len > 0) {
 162         i = ctx->buf_len - ctx->buf_off;
 163         if (i > outl)
 164             i = outl;
 165         memcpy(out, &(ctx->buf[ctx->buf_off]), i);
 166         ret = i;
 167         out += i;
 168         outl -= i;
 169         ctx->buf_off += i;
 170         if (ctx->buf_len == ctx->buf_off) {
 171             ctx->buf_len = 0;
 172             ctx->buf_off = 0;
 173         }
 174     }
 175
 176     /*
 177      * At this point, we have room of outl bytes and an empty buffer, so we
 178      * should read in some more.
 179      */
 180
 181     while (outl > 0) {
 182         if (ctx->cont <= 0)
 183             break;
 184
 185         /*
 186          * read in at IV offset, read the EVP_Cipher documentation about why
 187          */
 188         i = BIO_read(b->next_bio, &(ctx->buf[BUF_OFFSET]), ENC_BLOCK_SIZE);
 189
 190         if (i <= 0) {
 191             /* Should be continue next time we are called? */
 192             if (!BIO_should_retry(b->next_bio)) {
 193                 ctx->cont = i;
 194                 i = EVP_CipherFinal_ex(&(ctx->cipher),
 195                                        (unsigned char *)ctx->buf,
 196                                        &(ctx->buf_len));
 197                 ctx->ok = i;
 198                 ctx->buf_off = 0;
 199             } else {
 200                 ret = (ret == 0) ? i : ret;
 201                 break;
 202             }
 203         } else {
 204             EVP_CipherUpdate(&(ctx->cipher),
 205                              (unsigned char *)ctx->buf, &ctx->buf_len,
 206                              (unsigned char *)&(ctx->buf[BUF_OFFSET]), i);
 207             ctx->cont = 1;
 208             /*
 209              * Note: it is possible for EVP_CipherUpdate to decrypt zero
 210              * bytes because this is or looks like the final block: if this
 211              * happens we should retry and either read more data or decrypt
 212              * the final block
 213              */
 214             if (ctx->buf_len == 0)
 215                 continue;
 216         }
 217
 218         if (ctx->buf_len <= outl)
 219             i = ctx->buf_len;
 220         else
 221             i = outl;
 222         if (i <= 0)
 223             break;
 224         memcpy(out, ctx->buf, i);
 225         ret += i;
 226         ctx->buf_off = i;
 227         outl -= i;
 228         out += i;
 229     }
 230
 231     BIO_clear_retry_flags(b);
 232     BIO_copy_next_retry(b);
 233     return ((ret == 0) ? ctx->cont : ret);
 234 }
 235
 236 static int enc_write(BIO *b, const char *in, int inl)
 237 {
 238     int ret = 0, n, i;
 239     BIO_ENC_CTX *ctx;
 240
 241     ctx = (BIO_ENC_CTX *)b->ptr;
 242     ret = inl;
 243
 244     BIO_clear_retry_flags(b);
 245     n = ctx->buf_len - ctx->buf_off;
 246     while (n > 0) {
 247         i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
 248         if (i <= 0) {
 249             BIO_copy_next_retry(b);
 250             return (i);
 251         }
 252         ctx->buf_off += i;
 253         n -= i;
 254     }
 255     /* at this point all pending data has been written */
 256
 257     if ((in == NULL) || (inl <= 0))
 258         return (0);
 259
 260     ctx->buf_off = 0;
 261     while (inl > 0) {
 262         n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;
 263         EVP_CipherUpdate(&(ctx->cipher),
 264                          (unsigned char *)ctx->buf, &ctx->buf_len,
 265                          (unsigned char *)in, n);
 266         inl -= n;
 267         in += n;
 268
 269         ctx->buf_off = 0;
 270         n = ctx->buf_len;
 271         while (n > 0) {
 272             i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
 273             if (i <= 0) {
 274                 BIO_copy_next_retry(b);
 275                 return (ret == inl) ? i : ret - inl;
 276             }
 277             n -= i;
 278             ctx->buf_off += i;
 279         }
 280         ctx->buf_len = 0;
 281         ctx->buf_off = 0;
 282     }
 283     BIO_copy_next_retry(b);
 284     return (ret);
 285 }
 286
 287 static long enc_ctrl(BIO *b, int cmd, long num, void *ptr)
 288 {
 289     BIO *dbio;
 290     BIO_ENC_CTX *ctx, *dctx;
 291     long ret = 1;
 292     int i;
 293     EVP_CIPHER_CTX **c_ctx;
 294
 295     ctx = (BIO_ENC_CTX *)b->ptr;
 296
 297     switch (cmd) {
 298     case BIO_CTRL_RESET:
 299         ctx->ok = 1;
 300         ctx->finished = 0;
 301         EVP_CipherInit_ex(&(ctx->cipher), NULL, NULL, NULL, NULL,
 302                           ctx->cipher.encrypt);
 303         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 304         break;
 305     case BIO_CTRL_EOF:         /* More to read */
 306         if (ctx->cont <= 0)
 307             ret = 1;
 308         else
 309             ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 310         break;
 311     case BIO_CTRL_WPENDING:
 312         ret = ctx->buf_len - ctx->buf_off;
 313         if (ret <= 0)
 314             ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 315         break;
 316     case BIO_CTRL_PENDING:     /* More to read in buffer */
 317         ret = ctx->buf_len - ctx->buf_off;
 318         if (ret <= 0)
 319             ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 320         break;
 321     case BIO_CTRL_FLUSH:
 322         /* do a final write */
 323  again:
 324         while (ctx->buf_len != ctx->buf_off) {
 325             i = enc_write(b, NULL, 0);
 326             if (i < 0)
 327                 return i;
 328         }
 329
 330         if (!ctx->finished) {
 331             ctx->finished = 1;
 332             ctx->buf_off = 0;
 333             ret = EVP_CipherFinal_ex(&(ctx->cipher),
 334                                      (unsigned char *)ctx->buf,
 335                                      &(ctx->buf_len));
 336             ctx->ok = (int)ret;
 337             if (ret <= 0)
 338                 break;
 339
 340             /* push out the bytes */
 341             goto again;
 342         }
 343
 344         /* Finally flush the underlying BIO */
 345         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 346         break;
 347     case BIO_C_GET_CIPHER_STATUS:
 348         ret = (long)ctx->ok;
 349         break;
 350     case BIO_C_DO_STATE_MACHINE:
 351         BIO_clear_retry_flags(b);
 352         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 353         BIO_copy_next_retry(b);
 354         break;
 355     case BIO_C_GET_CIPHER_CTX:
 356         c_ctx = (EVP_CIPHER_CTX **)ptr;
 357         (*c_ctx) = &(ctx->cipher);
 358         b->init = 1;
 359         break;
 360     case BIO_CTRL_DUP:
 361         dbio = (BIO *)ptr;
 362         dctx = (BIO_ENC_CTX *)dbio->ptr;
 363         EVP_CIPHER_CTX_init(&dctx->cipher);
 364         ret = EVP_CIPHER_CTX_copy(&dctx->cipher, &ctx->cipher);
 365         if (ret)
 366             dbio->init = 1;
 367         break;
 368     default:
 369         ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
 370         break;
 371     }
 372     return (ret);
 373 }
 374
 375 static long enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
 376 {
 377     long ret = 1;
 378
 379     if (b->next_bio == NULL)
 380         return (0);
 381     switch (cmd) {
 382     default:
 383         ret = BIO_callback_ctrl(b->next_bio, cmd, fp);
 384         break;
 385     }
 386     return (ret);
 387 }
 388
 389 /*-
 390 void BIO_set_cipher_ctx(b,c)
 391 BIO *b;
 392 EVP_CIPHER_ctx *c;
 393         {
 394         if (b == NULL) return;
 395
 396         if ((b->callback != NULL) &&
 397                 (b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,0L) <= 0))
 398                 return;
 399
 400         b->init=1;
 401         ctx=(BIO_ENC_CTX *)b->ptr;
 402         memcpy(ctx->cipher,c,sizeof(EVP_CIPHER_CTX));
 403
 404         if (b->callback != NULL)
 405                 b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,1L);
 406         }
 407 */
 408
 409 void 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) <=
 419          0))
 420         return;
 421
 422     b->init = 1;
 423     ctx = (BIO_ENC_CTX *)b->ptr;
 424     EVP_CipherInit_ex(&(ctx->cipher), c, NULL, k, i, e);
 425
 426     if (b->callback != NULL)
 427         b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);
 428 }