1 /* crypto/des/enc_read.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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)"
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
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.]
64 /* This has some uglies in it but it works - even over sockets. */
66 int des_rw_mode=DES_PCBC_MODE;
72 * - The data format used by des_enc_write() and des_enc_read()
73 * has a cryptographic weakness: When asked to write more
74 * than MAXWRITE bytes, des_enc_write will split the data
75 * into several chunks that are all encrypted
76 * using the same IV. So don't use these functions unless you
77 * are sure you know what you do (in which case you might
78 * not want to use them anyway).
80 * - This code cannot handle non-blocking sockets.
82 * - This function uses an internal state and thus cannot be
83 * used on multiple files.
87 int des_enc_read(fd, buf, len, sched, iv)
91 des_key_schedule sched;
94 /* data to be unencrypted */
96 static unsigned char *net=NULL;
97 /* extra unencrypted data
98 * for when a block of 100 comes in but is des_read one byte at
100 static char *unnet=NULL;
101 static int unnet_start=0;
102 static int unnet_left=0;
103 static char *tmpbuf=NULL;
110 tmpbuf=(char *)Malloc(BSIZE);
111 if (tmpbuf == NULL) return(-1);
115 net=(unsigned char *)Malloc(BSIZE);
116 if (net == NULL) return(-1);
120 unnet=(char *)Malloc(BSIZE);
121 if (unnet == NULL) return(-1);
123 /* left over data from last decrypt */
126 if (unnet_left < len)
128 /* we still still need more data but will return
129 * with the number of bytes we have - should always
130 * check the return value */
131 memcpy(buf,&(unnet[unnet_start]),
132 (unsigned int)unnet_left);
133 /* eay 26/08/92 I had the next 2 lines
136 unnet_start=unnet_left=0;
140 memcpy(buf,&(unnet[unnet_start]),(unsigned int)len);
148 /* We need to get more data. */
149 if (len > MAXWRITE) len=MAXWRITE;
151 /* first - get the length */
152 while (net_num < HDRSIZE)
154 i=read(fd,&(net[net_num]),(unsigned int)HDRSIZE-net_num);
156 if ((i == -1) && (errno == EINTR)) continue;
158 if (i <= 0) return(0);
162 /* we now have at net_num bytes in net */
166 /* num should be rounded up to the next group of eight
167 * we make sure that we have read a multiple of 8 bytes from the net.
169 if ((num > MAXWRITE) || (num < 0)) /* error */
171 rnum=(num < 8)?8:((num+7)/8*8);
174 while (net_num < rnum)
176 i=read(fd,&(net[net_num]),(unsigned int)rnum-net_num);
178 if ((i == -1) && (errno == EINTR)) continue;
180 if (i <= 0) return(0);
184 /* Check if there will be data left over. */
187 if (des_rw_mode & DES_PCBC_MODE)
188 des_pcbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
190 des_cbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
191 memcpy(buf,unnet,(unsigned int)len);
193 unnet_left=(int)num-len;
195 /* The following line is done because we return num
196 * as the number of bytes read. */
201 /* >output is a multiple of 8 byes, if len < rnum
202 * >we must be careful. The user must be aware that this
203 * >routine will write more bytes than he asked for.
204 * >The length of the buffer must be correct.
205 * FIXED - Should be ok now 18-9-90 - eay */
209 if (des_rw_mode & DES_PCBC_MODE)
210 des_pcbc_encrypt(net,tmpbuf,num,sched,iv,
213 des_cbc_encrypt(net,tmpbuf,num,sched,iv,
216 /* eay 26/08/92 fix a bug that returned more
217 * bytes than you asked for (returned len bytes :-( */
218 memcpy(buf,tmpbuf,(unsigned int)num);
222 if (des_rw_mode & DES_PCBC_MODE)
223 des_pcbc_encrypt(net,buf,num,sched,iv,
226 des_cbc_encrypt(net,buf,num,sched,iv,