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