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 } 227 228