crypto/des/enc_read.c

   1 /* crypto/des/enc_read.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 "internal/cryptlib.h"
  62 #include "des_locl.h"
  63
  64 /* This has some uglies in it but it works - even over sockets. */
  65 /*
  66  * extern int errno;
  67  */
  68 OPENSSL_IMPLEMENT_GLOBAL(int, DES_rw_mode, DES_PCBC_MODE)
  69
  70 /*-
  71  * WARNINGS:
  72  *
  73  *  -  The data format used by DES_enc_write() and DES_enc_read()
  74  *     has a cryptographic weakness: When asked to write more
  75  *     than MAXWRITE bytes, DES_enc_write will split the data
  76  *     into several chunks that are all encrypted
  77  *     using the same IV.  So don't use these functions unless you
  78  *     are sure you know what you do (in which case you might
  79  *     not want to use them anyway).
  80  *
  81  *  -  This code cannot handle non-blocking sockets.
  82  *
  83  *  -  This function uses an internal state and thus cannot be
  84  *     used on multiple files.
  85  */
  86 int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched,
  87                  DES_cblock *iv)
  88 {
  89 #if defined(OPENSSL_NO_POSIX_IO)
  90     return (0);
  91 #else
  92     /* data to be unencrypted */
  93     int net_num = 0;
  94     static unsigned char *net = NULL;
  95     /*
  96      * extra unencrypted data for when a block of 100 comes in but is
  97      * des_read one byte at a time.
  98      */
  99     static unsigned char *unnet = NULL;
 100     static int unnet_start = 0;
 101     static int unnet_left = 0;
 102     static unsigned char *tmpbuf = NULL;
 103     int i;
 104     long num = 0, rnum;
 105     unsigned char *p;
 106
 107     if (tmpbuf == NULL) {
 108         tmpbuf = OPENSSL_malloc(BSIZE);
 109         if (tmpbuf == NULL)
 110             return (-1);
 111     }
 112     if (net == NULL) {
 113         net = OPENSSL_malloc(BSIZE);
 114         if (net == NULL)
 115             return (-1);
 116     }
 117     if (unnet == NULL) {
 118         unnet = OPENSSL_malloc(BSIZE);
 119         if (unnet == NULL)
 120             return (-1);
 121     }
 122     /* left over data from last decrypt */
 123     if (unnet_left != 0) {
 124         if (unnet_left < len) {
 125             /*
 126              * we still still need more data but will return with the number
 127              * of bytes we have - should always check the return value
 128              */
 129             memcpy(buf, &(unnet[unnet_start]), unnet_left);
 130             /*
 131              * eay 26/08/92 I had the next 2 lines reversed :-(
 132              */
 133             i = unnet_left;
 134             unnet_start = unnet_left = 0;
 135         } else {
 136             memcpy(buf, &(unnet[unnet_start]), len);
 137             unnet_start += len;
 138             unnet_left -= len;
 139             i = len;
 140         }
 141         return (i);
 142     }
 143
 144     /* We need to get more data. */
 145     if (len > MAXWRITE)
 146         len = MAXWRITE;
 147
 148     /* first - get the length */
 149     while (net_num < HDRSIZE) {
 150 # ifndef OPENSSL_SYS_WIN32
 151         i = read(fd, (void *)&(net[net_num]), HDRSIZE - net_num);
 152 # else
 153         i = _read(fd, (void *)&(net[net_num]), HDRSIZE - net_num);
 154 # endif
 155 # ifdef EINTR
 156         if ((i == -1) && (errno == EINTR))
 157             continue;
 158 # endif
 159         if (i <= 0)
 160             return (0);
 161         net_num += i;
 162     }
 163
 164     /* we now have at net_num bytes in net */
 165     p = net;
 166     /* num=0;  */
 167     n2l(p, num);
 168     /*
 169      * num should be rounded up to the next group of eight we make sure that
 170      * we have read a multiple of 8 bytes from the net.
 171      */
 172     if ((num > MAXWRITE) || (num < 0)) /* error */
 173         return (-1);
 174     rnum = (num < 8) ? 8 : ((num + 7) / 8 * 8);
 175
 176     net_num = 0;
 177     while (net_num < rnum) {
 178 # ifndef OPENSSL_SYS_WIN32
 179         i = read(fd, (void *)&(net[net_num]), rnum - net_num);
 180 # else
 181         i = _read(fd, (void *)&(net[net_num]), rnum - net_num);
 182 # endif
 183 # ifdef EINTR
 184         if ((i == -1) && (errno == EINTR))
 185             continue;
 186 # endif
 187         if (i <= 0)
 188             return (0);
 189         net_num += i;
 190     }
 191
 192     /* Check if there will be data left over. */
 193     if (len < num) {
 194         if (DES_rw_mode & DES_PCBC_MODE)
 195             DES_pcbc_encrypt(net, unnet, num, sched, iv, DES_DECRYPT);
 196         else
 197             DES_cbc_encrypt(net, unnet, num, sched, iv, DES_DECRYPT);
 198         memcpy(buf, unnet, len);
 199         unnet_start = len;
 200         unnet_left = num - len;
 201
 202         /*
 203          * The following line is done because we return num as the number of
 204          * bytes read.
 205          */
 206         num = len;
 207     } else {
 208         /*-
 209          * >output is a multiple of 8 byes, if len < rnum
 210          * >we must be careful.  The user must be aware that this
 211          * >routine will write more bytes than he asked for.
 212          * >The length of the buffer must be correct.
 213          * FIXED - Should be ok now 18-9-90 - eay */
 214         if (len < rnum) {
 215
 216             if (DES_rw_mode & DES_PCBC_MODE)
 217                 DES_pcbc_encrypt(net, tmpbuf, num, sched, iv, DES_DECRYPT);
 218             else
 219                 DES_cbc_encrypt(net, tmpbuf, num, sched, iv, DES_DECRYPT);
 220
 221             /*
 222              * eay 26/08/92 fix a bug that returned more bytes than you asked
 223              * for (returned len bytes :-(
 224              */
 225             memcpy(buf, tmpbuf, num);
 226         } else {
 227             if (DES_rw_mode & DES_PCBC_MODE)
 228                 DES_pcbc_encrypt(net, buf, num, sched, iv, DES_DECRYPT);
 229             else
 230                 DES_cbc_encrypt(net, buf, num, sched, iv, DES_DECRYPT);
 231         }
 232     }
 233     return num;
 234 #endif                          /* OPENSSL_NO_POSIX_IO */
 235 }