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