1 /* $OpenBSD: enc_read.c,v 1.15 2015/02/12 03:54:07 jsing Exp $ */
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 <errno.h>
60 #include <stdio.h>
61
62 #include <openssl/opensslconf.h>
63
64 #include "des_locl.h"
65
66 /* This has some uglies in it but it works - even over sockets. */
67 /*extern int errno;*/
68 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 */
86
87
DES_enc_read(int fd,void * buf,int len,DES_key_schedule * sched,DES_cblock * iv)88 int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched,
89 DES_cblock *iv)
90 {
91 /* data to be unencrypted */
92 int net_num=0;
93 static unsigned char *net=NULL;
94 /* extra unencrypted data
95 * for when a block of 100 comes in but is des_read one byte at
96 * a time. */
97 static unsigned char *unnet=NULL;
98 static int unnet_start=0;
99 static int unnet_left=0;
100 static unsigned char *tmpbuf=NULL;
101 int i;
102 long num=0,rnum;
103 unsigned char *p;
104
105 if (tmpbuf == NULL)
106 {
107 tmpbuf=malloc(BSIZE);
108 if (tmpbuf == NULL) return(-1);
109 }
110 if (net == NULL)
111 {
112 net=malloc(BSIZE);
113 if (net == NULL) return(-1);
114 }
115 if (unnet == NULL)
116 {
117 unnet=malloc(BSIZE);
118 if (unnet == NULL) return(-1);
119 }
120 /* left over data from last decrypt */
121 if (unnet_left != 0)
122 {
123 if (unnet_left < len)
124 {
125 /* we still still need more data but will return
126 * with the number of bytes we have - should always
127 * check the return value */
128 memcpy(buf,&(unnet[unnet_start]),
129 unnet_left);
130 /* eay 26/08/92 I had the next 2 lines
131 * reversed :-( */
132 i=unnet_left;
133 unnet_start=unnet_left=0;
134 }
135 else
136 {
137 memcpy(buf,&(unnet[unnet_start]),len);
138 unnet_start+=len;
139 unnet_left-=len;
140 i=len;
141 }
142 return(i);
143 }
144
145 /* We need to get more data. */
146 if (len > MAXWRITE) len=MAXWRITE;
147
148 /* first - get the length */
149 while (net_num < HDRSIZE)
150 {
151 i=read(fd,(void *)&(net[net_num]),HDRSIZE-net_num);
152 #ifdef EINTR
153 if ((i == -1) && (errno == EINTR)) continue;
154 #endif
155 if (i <= 0) return(0);
156 net_num+=i;
157 }
158
159 /* we now have at net_num bytes in net */
160 p=net;
161 /* num=0; */
162 n2l(p,num);
163 /* num should be rounded up to the next group of eight
164 * we make sure that we have read a multiple of 8 bytes from the net.
165 */
166 if ((num > MAXWRITE) || (num < 0)) /* error */
167 return(-1);
168 rnum=(num < 8)?8:((num+7)/8*8);
169
170 net_num=0;
171 while (net_num < rnum)
172 {
173 i=read(fd,(void *)&(net[net_num]),rnum-net_num);
174 #ifdef EINTR
175 if ((i == -1) && (errno == EINTR)) continue;
176 #endif
177 if (i <= 0) return(0);
178 net_num+=i;
179 }
180
181 /* Check if there will be data left over. */
182 if (len < num)
183 {
184 if (DES_rw_mode & DES_PCBC_MODE)
185 DES_pcbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
186 else
187 DES_cbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
188 memcpy(buf,unnet,len);
189 unnet_start=len;
190 unnet_left=num-len;
191
192 /* The following line is done because we return num
193 * as the number of bytes read. */
194 num=len;
195 }
196 else
197 {
198 /* >output is a multiple of 8 byes, if len < rnum
199 * >we must be careful. The user must be aware that this
200 * >routine will write more bytes than he asked for.
201 * >The length of the buffer must be correct.
202 * FIXED - Should be ok now 18-9-90 - eay */
203 if (len < rnum)
204 {
205
206 if (DES_rw_mode & DES_PCBC_MODE)
207 DES_pcbc_encrypt(net,tmpbuf,num,sched,iv,
208 DES_DECRYPT);
209 else
210 DES_cbc_encrypt(net,tmpbuf,num,sched,iv,
211 DES_DECRYPT);
212
213 /* eay 26/08/92 fix a bug that returned more
214 * bytes than you asked for (returned len bytes :-( */
215 memcpy(buf,tmpbuf,num);
216 }
217 else
218 {
219 if (DES_rw_mode & DES_PCBC_MODE)
220 DES_pcbc_encrypt(net,buf,num,sched,iv,
221 DES_DECRYPT);
222 else
223 DES_cbc_encrypt(net,buf,num,sched,iv,
224 DES_DECRYPT);
225 }
226 }
227 return num;
228 }
229
230