des_enc_read(fd,buf,len,sched,iv)1 /* crypto/des/enc_read.c */
2 /* Copyright (C) 1995-1997 Eric Young (eay@mincom.oz.au)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@mincom.oz.au).
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@mincom.oz.au).
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@mincom.oz.au)"
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@mincom.oz.au)"
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 int des_enc_read(fd, buf, len, sched, iv)
68 int fd;
69 char *buf;
70 int len;
71 des_key_schedule sched;
72 des_cblock (*iv);
73 {
74 /* data to be unencrypted */
75 int net_num=0;
76 static unsigned char *net=NULL;
77 /* extra unencrypted data
78 * for when a block of 100 comes in but is des_read one byte at
79 * a time. */
80 static char *unnet=NULL;
81 static int unnet_start=0;
82 static int unnet_left=0;
83 static char *tmpbuf=NULL;
84 int i;
85 long num=0,rnum;
86 unsigned char *p;
87
88 if (tmpbuf == NULL)
89 {
90 tmpbuf=(char *)malloc(BSIZE);
91 if (tmpbuf == NULL) return(-1);
92 }
93 if (net == NULL)
94 {
95 net=(unsigned char *)malloc(BSIZE);
96 if (net == NULL) return(-1);
97 }
98 if (unnet == NULL)
99 {
100 unnet=(char *)malloc(BSIZE);
101 if (unnet == NULL) return(-1);
102 }
103 /* left over data from last decrypt */
104 if (unnet_left != 0)
105 {
106 if (unnet_left < len)
107 {
108 /* we still still need more data but will return
109 * with the number of bytes we have - should always
110 * check the return value */
111 memcpy(buf,&(unnet[unnet_start]),
112 (unsigned int)unnet_left);
113 /* eay 26/08/92 I had the next 2 lines
114 * reversed :-( */
115 i=unnet_left;
116 unnet_start=unnet_left=0;
117 }
118 else
119 {
120 memcpy(buf,&(unnet[unnet_start]),(unsigned int)len);
121 unnet_start+=len;
122 unnet_left-=len;
123 i=len;
124 }
125 return(i);
126 }
127
128 /* We need to get more data. */
129 if (len > MAXWRITE) len=MAXWRITE;
130
131 /* first - get the length */
132 while (net_num < HDRSIZE)
133 {
134 i=read(fd,&(net[net_num]),(unsigned int)HDRSIZE-net_num);
135 if ((i == -1) && (errno == EINTR)) continue;
136 if (i <= 0) return(0);
137 net_num+=i;
138 }
139
140 /* we now have at net_num bytes in net */
141 p=net;
142 /* num=0; */
143 n2l(p,num);
144 /* num should be rounded up to the next group of eight
145 * we make sure that we have read a multiple of 8 bytes from the net.
146 */
147 if ((num > MAXWRITE) || (num < 0)) /* error */
148 return(-1);
149 rnum=(num < 8)?8:((num+7)/8*8);
150
151 net_num=0;
152 while (net_num < rnum)
153 {
154 i=read(fd,&(net[net_num]),(unsigned int)rnum-net_num);
155 if ((i == -1) && (errno == EINTR)) continue;
156 if (i <= 0) return(0);
157 net_num+=i;
158 }
159
160 /* Check if there will be data left over. */
161 if (len < num)
162 {
163 if (des_rw_mode & DES_PCBC_MODE)
164 des_pcbc_encrypt((des_cblock *)net,(des_cblock *)unnet,
165 num,sched,iv,DES_DECRYPT);
166 else
167 des_cbc_encrypt((des_cblock *)net,(des_cblock *)unnet,
168 num,sched,iv,DES_DECRYPT);
169 memcpy(buf,unnet,(unsigned int)len);
170 unnet_start=len;
171 unnet_left=(int)num-len;
172
173 /* The following line is done because we return num
174 * as the number of bytes read. */
175 num=len;
176 }
177 else
178 {
179 /* >output is a multiple of 8 byes, if len < rnum
180 * >we must be careful. The user must be aware that this
181 * >routine will write more bytes than he asked for.
182 * >The length of the buffer must be correct.
183 * FIXED - Should be ok now 18-9-90 - eay */
184 if (len < rnum)
185 {
186
187 if (des_rw_mode & DES_PCBC_MODE)
188 des_pcbc_encrypt((des_cblock *)net,
189 (des_cblock *)tmpbuf,
190 num,sched,iv,DES_DECRYPT);
191 else
192 des_cbc_encrypt((des_cblock *)net,
193 (des_cblock *)tmpbuf,
194 num,sched,iv,DES_DECRYPT);
195
196 /* eay 26/08/92 fix a bug that returned more
197 * bytes than you asked for (returned len bytes :-( */
198 memcpy(buf,tmpbuf,(unsigned int)num);
199 }
200 else
201 {
202 if (des_rw_mode & DES_PCBC_MODE)
203 des_pcbc_encrypt((des_cblock *)net,
204 (des_cblock *)buf,num,sched,iv,
205 DES_DECRYPT);
206 else
207 des_cbc_encrypt((des_cblock *)net,
208 (des_cblock *)buf,num,sched,iv,
209 DES_DECRYPT);
210 }
211 }
212 return((int)num);
213 }
214
215