crypto/heimdal-0.6.3/lib/des/enc_read.c

   1 /* crypto/des/enc_read.c */
   2 /* Copyright (C) 1995-1997 Eric Young (eay@mincom.oz.au)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@mincom.oz.au).
   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@mincom.oz.au).
  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@mincom.oz.au)"
  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@mincom.oz.au)"
  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 "des_locl.h"
  62
  63 /* This has some uglies in it but it works - even over sockets. */
  64 /*extern int errno;*/
  65 int des_rw_mode=DES_PCBC_MODE;
  66
  67 int des_enc_read(fd, buf, len, sched, iv)
  68 int fd;
  69 char *buf;
  70 int len;
  71 des_key_schedule sched;
  72 des_cblock (*iv);
  73         {
  74         /* data to be unencrypted */
  75         int net_num=0;
  76         static unsigned char *net=NULL;
  77         /* extra unencrypted data
  78          * for when a block of 100 comes in but is des_read one byte at
  79          * a time. */
  80         static char *unnet=NULL;
  81         static int unnet_start=0;
  82         static int unnet_left=0;
  83         static char *tmpbuf=NULL;
  84         int i;
  85         long num=0,rnum;
  86         unsigned char *p;
  87
  88         if (tmpbuf == NULL)
  89                 {
  90                 tmpbuf=(char *)malloc(des_BSIZE);
  91                 if (tmpbuf == NULL) return(-1);
  92                 }
  93         if (net == NULL)
  94                 {
  95                 net=(unsigned char *)malloc(des_BSIZE);
  96                 if (net == NULL) return(-1);
  97                 }
  98         if (unnet == NULL)
  99                 {
 100                 unnet=(char *)malloc(des_BSIZE);
 101                 if (unnet == NULL) return(-1);
 102                 }
 103         /* left over data from last decrypt */
 104         if (unnet_left != 0)
 105                 {
 106                 if (unnet_left < len)
 107                         {
 108                         /* we still still need more data but will return
 109                          * with the number of bytes we have - should always
 110                          * check the return value */
 111                         memcpy(buf,&(unnet[unnet_start]),
 112                                 (unsigned int)unnet_left);
 113                         /* eay 26/08/92 I had the next 2 lines
 114                          * reversed :-( */
 115                         i=unnet_left;
 116                         unnet_start=unnet_left=0;
 117                         }
 118                 else
 119                         {
 120                         memcpy(buf,&(unnet[unnet_start]),(unsigned int)len);
 121                         unnet_start+=len;
 122                         unnet_left-=len;
 123                         i=len;
 124                         }
 125                 return(i);
 126                 }
 127
 128         /* We need to get more data. */
 129         if (len > MAXWRITE) len=MAXWRITE;
 130
 131         /* first - get the length */
 132         while (net_num < HDRSIZE)
 133                 {
 134                 i=read(fd,&(net[net_num]),(unsigned int)HDRSIZE-net_num);
 135                 if ((i == -1) && (errno == EINTR)) continue;
 136                 if (i <= 0) return(0);
 137                 net_num+=i;
 138                 }
 139
 140         /* we now have at net_num bytes in net */
 141         p=net;
 142         /* num=0;  */
 143         n2l(p,num);
 144         /* num should be rounded up to the next group of eight
 145          * we make sure that we have read a multiple of 8 bytes from the net.
 146          */
 147         if ((num > MAXWRITE) || (num < 0)) /* error */
 148                 return(-1);
 149         rnum=(num < 8)?8:((num+7)/8*8);
 150
 151         net_num=0;
 152         while (net_num < rnum)
 153                 {
 154                 i=read(fd,&(net[net_num]),(unsigned int)rnum-net_num);
 155                 if ((i == -1) && (errno == EINTR)) continue;
 156                 if (i <= 0) return(0);
 157                 net_num+=i;
 158                 }
 159
 160         /* Check if there will be data left over. */
 161         if (len < num)
 162                 {
 163                 if (des_rw_mode & DES_PCBC_MODE)
 164                         des_pcbc_encrypt((des_cblock *)net,(des_cblock *)unnet,
 165                                 num,sched,iv,DES_DECRYPT);
 166                 else
 167                         des_cbc_encrypt((des_cblock *)net,(des_cblock *)unnet,
 168                                 num,sched,iv,DES_DECRYPT);
 169                 memcpy(buf,unnet,(unsigned int)len);
 170                 unnet_start=len;
 171                 unnet_left=(int)num-len;
 172
 173                 /* The following line is done because we return num
 174                  * as the number of bytes read. */
 175                 num=len;
 176                 }
 177         else
 178                 {
 179                 /* >output is a multiple of 8 byes, if len < rnum
 180                  * >we must be careful.  The user must be aware that this
 181                  * >routine will write more bytes than he asked for.
 182                  * >The length of the buffer must be correct.
 183                  * FIXED - Should be ok now 18-9-90 - eay */
 184                 if (len < rnum)
 185                         {
 186
 187                         if (des_rw_mode & DES_PCBC_MODE)
 188                                 des_pcbc_encrypt((des_cblock *)net,
 189                                         (des_cblock *)tmpbuf,
 190                                         num,sched,iv,DES_DECRYPT);
 191                         else
 192                                 des_cbc_encrypt((des_cblock *)net,
 193                                         (des_cblock *)tmpbuf,
 194                                         num,sched,iv,DES_DECRYPT);
 195
 196                         /* eay 26/08/92 fix a bug that returned more
 197                          * bytes than you asked for (returned len bytes :-( */
 198                         memcpy(buf,tmpbuf,(unsigned int)num);
 199                         }
 200                 else
 201                         {
 202                         if (des_rw_mode & DES_PCBC_MODE)
 203                                 des_pcbc_encrypt((des_cblock *)net,
 204                                         (des_cblock *)buf,num,sched,iv,
 205                                         DES_DECRYPT);
 206                         else
 207                                 des_cbc_encrypt((des_cblock *)net,
 208                                         (des_cblock *)buf,num,sched,iv,
 209                                         DES_DECRYPT);
 210                         }
 211                 }
 212         return((int)num);
 213         }
 214