enc_read.c 7.38 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240
/* crypto/des/enc_read.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include <errno.h>
#include "cryptlib.h"
#include "des_locl.h"

/* This has some uglies in it but it works - even over sockets. */
/*extern int errno;*/
OPENSSL_IMPLEMENT_GLOBAL(int,DES_rw_mode,DES_PCBC_MODE)


/*
 * WARNINGS:
 *
 *  -  The data format used by DES_enc_write() and DES_enc_read()
 *     has a cryptographic weakness: When asked to write more
 *     than MAXWRITE bytes, DES_enc_write will split the data
 *     into several chunks that are all encrypted
 *     using the same IV.  So don't use these functions unless you
 *     are sure you know what you do (in which case you might
 *     not want to use them anyway).
 *
 *  -  This code cannot handle non-blocking sockets.
 *
 *  -  This function uses an internal state and thus cannot be
 *     used on multiple files.
 */


int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched,
		 DES_cblock *iv)
	{
#if defined(OPENSSL_NO_POSIX_IO)
	return(0);
#else
	/* data to be unencrypted */
	int net_num=0;
	static unsigned char *net=NULL;
	/* extra unencrypted data 
	 * for when a block of 100 comes in but is des_read one byte at
	 * a time. */
	static unsigned char *unnet=NULL;
	static int unnet_start=0;
	static int unnet_left=0;
	static unsigned char *tmpbuf=NULL;
	int i;
	long num=0,rnum;
	unsigned char *p;

	if (tmpbuf == NULL)
		{
		tmpbuf=OPENSSL_malloc(BSIZE);
		if (tmpbuf == NULL) return(-1);
		}
	if (net == NULL)
		{
		net=OPENSSL_malloc(BSIZE);
		if (net == NULL) return(-1);
		}
	if (unnet == NULL)
		{
		unnet=OPENSSL_malloc(BSIZE);
		if (unnet == NULL) return(-1);
		}
	/* left over data from last decrypt */
	if (unnet_left != 0)
		{
		if (unnet_left < len)
			{
			/* we still still need more data but will return
			 * with the number of bytes we have - should always
			 * check the return value */
			memcpy(buf,&(unnet[unnet_start]),
			       unnet_left);
			/* eay 26/08/92 I had the next 2 lines
			 * reversed :-( */
			i=unnet_left;
			unnet_start=unnet_left=0;
			}
		else
			{
			memcpy(buf,&(unnet[unnet_start]),len);
			unnet_start+=len;
			unnet_left-=len;
			i=len;
			}
		return(i);
		}

	/* We need to get more data. */
	if (len > MAXWRITE) len=MAXWRITE;

	/* first - get the length */
	while (net_num < HDRSIZE) 
		{
#ifndef OPENSSL_SYS_WIN32
		i=read(fd,(void *)&(net[net_num]),HDRSIZE-net_num);
#else
		i=_read(fd,(void *)&(net[net_num]),HDRSIZE-net_num);
#endif
#ifdef EINTR
		if ((i == -1) && (errno == EINTR)) continue;
#endif
		if (i <= 0) return(0);
		net_num+=i;
		}

	/* we now have at net_num bytes in net */
	p=net;
	/* num=0;  */
	n2l(p,num);
	/* num should be rounded up to the next group of eight
	 * we make sure that we have read a multiple of 8 bytes from the net.
	 */
	if ((num > MAXWRITE) || (num < 0)) /* error */
		return(-1);
	rnum=(num < 8)?8:((num+7)/8*8);

	net_num=0;
	while (net_num < rnum)
		{
#ifndef OPENSSL_SYS_WIN32
		i=read(fd,(void *)&(net[net_num]),rnum-net_num);
#else
		i=_read(fd,(void *)&(net[net_num]),rnum-net_num);
#endif
#ifdef EINTR
		if ((i == -1) && (errno == EINTR)) continue;
#endif
		if (i <= 0) return(0);
		net_num+=i;
		}

	/* Check if there will be data left over. */
	if (len < num)
		{
		if (DES_rw_mode & DES_PCBC_MODE)
			DES_pcbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
		else
			DES_cbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
		memcpy(buf,unnet,len);
		unnet_start=len;
		unnet_left=num-len;

		/* The following line is done because we return num
		 * as the number of bytes read. */
		num=len;
		}
	else
		{
		/* >output is a multiple of 8 byes, if len < rnum
		 * >we must be careful.  The user must be aware that this
		 * >routine will write more bytes than he asked for.
		 * >The length of the buffer must be correct.
		 * FIXED - Should be ok now 18-9-90 - eay */
		if (len < rnum)
			{

			if (DES_rw_mode & DES_PCBC_MODE)
				DES_pcbc_encrypt(net,tmpbuf,num,sched,iv,
						 DES_DECRYPT);
			else
				DES_cbc_encrypt(net,tmpbuf,num,sched,iv,
						DES_DECRYPT);

			/* eay 26/08/92 fix a bug that returned more
			 * bytes than you asked for (returned len bytes :-( */
			memcpy(buf,tmpbuf,num);
			}
		else
			{
			if (DES_rw_mode & DES_PCBC_MODE)
				DES_pcbc_encrypt(net,buf,num,sched,iv,
						 DES_DECRYPT);
			else
				DES_cbc_encrypt(net,buf,num,sched,iv,
						DES_DECRYPT);
			}
		}
	return num;
#endif /* OPENSSL_NO_POSIX_IO */
	}