1 /* crypto/des/enc_read.c */ 2 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay (at) 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 (at) 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 (at) 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 (at) 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 #ifndef OPENSSL_SYS_WIN32 154 i=read(fd,(void *)&(net[net_num]),HDRSIZE-net_num); 155 #else 156 i=_read(fd,(void *)&(net[net_num]),HDRSIZE-net_num); 157 #endif 158 #ifdef EINTR 159 if ((i == -1) && (errno == EINTR)) continue; 160 #endif 161 if (i <= 0) return(0); 162 net_num+=i; 163 } 164 165 /* we now have at net_num bytes in net */ 166 p=net; 167 /* num=0; */ 168 n2l(p,num); 169 /* num should be rounded up to the next group of eight 170 * we make sure that 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 { 179 #ifndef OPENSSL_SYS_WIN32 180 i=read(fd,(void *)&(net[net_num]),rnum-net_num); 181 #else 182 i=_read(fd,(void *)&(net[net_num]),rnum-net_num); 183 #endif 184 #ifdef EINTR 185 if ((i == -1) && (errno == EINTR)) continue; 186 #endif 187 if (i <= 0) return(0); 188 net_num+=i; 189 } 190 191 /* Check if there will be data left over. */ 192 if (len < num) 193 { 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 /* The following line is done because we return num 203 * as the number of bytes read. */ 204 num=len; 205 } 206 else 207 { 208 /* >output is a multiple of 8 byes, if len < rnum 209 * >we must be careful. The user must be aware that this 210 * >routine will write more bytes than he asked for. 211 * >The length of the buffer must be correct. 212 * FIXED - Should be ok now 18-9-90 - eay */ 213 if (len < rnum) 214 { 215 216 if (DES_rw_mode & DES_PCBC_MODE) 217 DES_pcbc_encrypt(net,tmpbuf,num,sched,iv, 218 DES_DECRYPT); 219 else 220 DES_cbc_encrypt(net,tmpbuf,num,sched,iv, 221 DES_DECRYPT); 222 223 /* eay 26/08/92 fix a bug that returned more 224 * bytes than you asked for (returned len bytes :-( */ 225 memcpy(buf,tmpbuf,num); 226 } 227 else 228 { 229 if (DES_rw_mode & DES_PCBC_MODE) 230 DES_pcbc_encrypt(net,buf,num,sched,iv, 231 DES_DECRYPT); 232 else 233 DES_cbc_encrypt(net,buf,num,sched,iv, 234 DES_DECRYPT); 235 } 236 } 237 return num; 238 #endif /* OPENSSL_NO_POSIX_IO */ 239 } 240 241
