enc_read.c revision 280304
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/* 66 * extern int errno; 67 */ 68OPENSSL_IMPLEMENT_GLOBAL(int, DES_rw_mode, DES_PCBC_MODE) 69 70/*- 71 * WARNINGS: 72 * 73 * - The data format used by DES_enc_write() and DES_enc_read() 74 * has a cryptographic weakness: When asked to write more 75 * than MAXWRITE bytes, DES_enc_write will split the data 76 * into several chunks that are all encrypted 77 * using the same IV. So don't use these functions unless you 78 * are sure you know what you do (in which case you might 79 * not want to use them anyway). 80 * 81 * - This code cannot handle non-blocking sockets. 82 * 83 * - This function uses an internal state and thus cannot be 84 * used on multiple files. 85 */ 86int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched, 87 DES_cblock *iv) 88{ 89#if defined(OPENSSL_NO_POSIX_IO) 90 return (0); 91#else 92 /* data to be unencrypted */ 93 int net_num = 0; 94 static unsigned char *net = NULL; 95 /* 96 * extra unencrypted data for when a block of 100 comes in but is 97 * des_read one byte at a time. 98 */ 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 tmpbuf = OPENSSL_malloc(BSIZE); 109 if (tmpbuf == NULL) 110 return (-1); 111 } 112 if (net == NULL) { 113 net = OPENSSL_malloc(BSIZE); 114 if (net == NULL) 115 return (-1); 116 } 117 if (unnet == NULL) { 118 unnet = OPENSSL_malloc(BSIZE); 119 if (unnet == NULL) 120 return (-1); 121 } 122 /* left over data from last decrypt */ 123 if (unnet_left != 0) { 124 if (unnet_left < len) { 125 /* 126 * we still still need more data but will return with the number 127 * of bytes we have - should always check the return value 128 */ 129 memcpy(buf, &(unnet[unnet_start]), unnet_left); 130 /* 131 * eay 26/08/92 I had the next 2 lines reversed :-( 132 */ 133 i = unnet_left; 134 unnet_start = unnet_left = 0; 135 } else { 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) 146 len = MAXWRITE; 147 148 /* first - get the length */ 149 while (net_num < HDRSIZE) { 150# ifndef OPENSSL_SYS_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)) 157 continue; 158# endif 159 if (i <= 0) 160 return (0); 161 net_num += i; 162 } 163 164 /* we now have at net_num bytes in net */ 165 p = net; 166 /* num=0; */ 167 n2l(p, num); 168 /* 169 * num should be rounded up to the next group of eight we make sure that 170 * 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# ifndef OPENSSL_SYS_WIN32 179 i = read(fd, (void *)&(net[net_num]), rnum - net_num); 180# else 181 i = _read(fd, (void *)&(net[net_num]), rnum - net_num); 182# endif 183# ifdef EINTR 184 if ((i == -1) && (errno == EINTR)) 185 continue; 186# endif 187 if (i <= 0) 188 return (0); 189 net_num += i; 190 } 191 192 /* Check if there will be data left over. */ 193 if (len < num) { 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 /* 203 * The following line is done because we return num as the number of 204 * bytes read. 205 */ 206 num = len; 207 } else { 208 /*- 209 * >output is a multiple of 8 byes, if len < rnum 210 * >we must be careful. The user must be aware that this 211 * >routine will write more bytes than he asked for. 212 * >The length of the buffer must be correct. 213 * FIXED - Should be ok now 18-9-90 - eay */ 214 if (len < rnum) { 215 216 if (DES_rw_mode & DES_PCBC_MODE) 217 DES_pcbc_encrypt(net, tmpbuf, num, sched, iv, DES_DECRYPT); 218 else 219 DES_cbc_encrypt(net, tmpbuf, num, sched, iv, DES_DECRYPT); 220 221 /* 222 * eay 26/08/92 fix a bug that returned more bytes than you asked 223 * for (returned len bytes :-( 224 */ 225 memcpy(buf, tmpbuf, num); 226 } else { 227 if (DES_rw_mode & DES_PCBC_MODE) 228 DES_pcbc_encrypt(net, buf, num, sched, iv, DES_DECRYPT); 229 else 230 DES_cbc_encrypt(net, buf, num, sched, iv, DES_DECRYPT); 231 } 232 } 233 return num; 234#endif /* OPENSSL_NO_POSIX_IO */ 235} 236