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;*/ 66OPENSSL_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 87int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched, 88 DES_cblock *iv) 89 { 90 /* data to be unencrypted */ 91 int net_num=0; 92 static unsigned char *net=NULL; 93 /* extra unencrypted data 94 * for when a block of 100 comes in but is des_read one byte at 95 * a time. */ 96 static unsigned char *unnet=NULL; 97 static int unnet_start=0; 98 static int unnet_left=0; 99 static unsigned char *tmpbuf=NULL; 100 int i; 101 long num=0,rnum; 102 unsigned char *p; 103 104 if (tmpbuf == NULL) 105 { 106 tmpbuf=OPENSSL_malloc(BSIZE); 107 if (tmpbuf == NULL) return(-1); 108 } 109 if (net == NULL) 110 { 111 net=OPENSSL_malloc(BSIZE); 112 if (net == NULL) return(-1); 113 } 114 if (unnet == NULL) 115 { 116 unnet=OPENSSL_malloc(BSIZE); 117 if (unnet == NULL) return(-1); 118 } 119 /* left over data from last decrypt */ 120 if (unnet_left != 0) 121 { 122 if (unnet_left < len) 123 { 124 /* we still still need more data but will return 125 * with the number of bytes we have - should always 126 * check the return value */ 127 memcpy(buf,&(unnet[unnet_start]), 128 unnet_left); 129 /* eay 26/08/92 I had the next 2 lines 130 * reversed :-( */ 131 i=unnet_left; 132 unnet_start=unnet_left=0; 133 } 134 else 135 { 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) len=MAXWRITE; 146 147 /* first - get the length */ 148 while (net_num < HDRSIZE) 149 { 150#ifndef _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)) continue; 157#endif 158 if (i <= 0) return(0); 159 net_num+=i; 160 } 161 162 /* we now have at net_num bytes in net */ 163 p=net; 164 /* num=0; */ 165 n2l(p,num); 166 /* num should be rounded up to the next group of eight 167 * we make sure that we have read a multiple of 8 bytes from the net. 168 */ 169 if ((num > MAXWRITE) || (num < 0)) /* error */ 170 return(-1); 171 rnum=(num < 8)?8:((num+7)/8*8); 172 173 net_num=0; 174 while (net_num < rnum) 175 { 176 i=read(fd,(void *)&(net[net_num]),rnum-net_num); 177#ifdef EINTR 178 if ((i == -1) && (errno == EINTR)) continue; 179#endif 180 if (i <= 0) return(0); 181 net_num+=i; 182 } 183 184 /* Check if there will be data left over. */ 185 if (len < num) 186 { 187 if (DES_rw_mode & DES_PCBC_MODE) 188 DES_pcbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT); 189 else 190 DES_cbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT); 191 memcpy(buf,unnet,len); 192 unnet_start=len; 193 unnet_left=num-len; 194 195 /* The following line is done because we return num 196 * as the number of bytes read. */ 197 num=len; 198 } 199 else 200 { 201 /* >output is a multiple of 8 byes, if len < rnum 202 * >we must be careful. The user must be aware that this 203 * >routine will write more bytes than he asked for. 204 * >The length of the buffer must be correct. 205 * FIXED - Should be ok now 18-9-90 - eay */ 206 if (len < rnum) 207 { 208 209 if (DES_rw_mode & DES_PCBC_MODE) 210 DES_pcbc_encrypt(net,tmpbuf,num,sched,iv, 211 DES_DECRYPT); 212 else 213 DES_cbc_encrypt(net,tmpbuf,num,sched,iv, 214 DES_DECRYPT); 215 216 /* eay 26/08/92 fix a bug that returned more 217 * bytes than you asked for (returned len bytes :-( */ 218 memcpy(buf,tmpbuf,num); 219 } 220 else 221 { 222 if (DES_rw_mode & DES_PCBC_MODE) 223 DES_pcbc_encrypt(net,buf,num,sched,iv, 224 DES_DECRYPT); 225 else 226 DES_cbc_encrypt(net,buf,num,sched,iv, 227 DES_DECRYPT); 228 } 229 } 230 return num; 231 } 232 233