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
|
/*
* $Source$
* $Author$
*
* Copyright 1985, 1986, 1987, 1988, 1990 by the Massachusetts Institute
* of Technology.
* All Rights Reserved.
*
* These routines perform encryption and decryption using the DES
* private key algorithm, or else a subset of it -- fewer inner loops.
* (AUTH_DES_ITER defaults to 16, may be less.)
*
* Under U.S. law, this software may not be exported outside the US
* without license from the U.S. Commerce department.
*
* These routines form the library interface to the DES facilities.
*
* Originally written 8/85 by Steve Miller, MIT Project Athena.
*
* Export of this software from the United States of America is assumed
* to require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
*/
#if !defined(lint) && !defined(SABER)
static char rcsid_enc_dec_c[] =
"$Id$";
#endif /* !lint & !SABER */
#include <krb5/krb5.h>
#include <krb5/ext-proto.h>
#include <krb5/crc-32.h>
#include "des_int.h"
#ifdef DEBUG
#include <stdio.h>
extern int mit_des_debug;
#endif
/*
* This routine performs DES cipher-block-chaining operation, either
* encrypting from cleartext to ciphertext, if encrypt != 0 or
* decrypting from ciphertext to cleartext, if encrypt == 0.
*
* The key schedule is passed as an arg, as well as the cleartext or
* ciphertext. The cleartext and ciphertext should be in host order.
*
* NOTE-- the output is ALWAYS an multiple of 8 bytes long. If not
* enough space was provided, your program will get trashed.
*
* For encryption, the cleartext string is null padded, at the end, to
* an integral multiple of eight bytes.
*
* For decryption, the ciphertext will be used in integral multiples
* of 8 bytes, but only the first "length" bytes returned into the
* cleartext.
*/
krb5_error_code
mit_des_cbc_encrypt(in,out,length,key,iv,encrypt)
krb5_octet *in; /* >= length bytes of input text */
krb5_octet *out; /* >= length bytes of output text */
register long length; /* in bytes */
mit_des_key_schedule key; /* precomputed key schedule */
krb5_octet *iv; /* 8 bytes of ivec */
int encrypt; /* 0 ==> decrypt, else encrypt */
{
int mit_des_ecb_encrypt();
register unsigned long *input = (unsigned long *) in;
register unsigned long *output = (unsigned long *) out;
register unsigned long *ivec = (unsigned long *) iv;
unsigned long i,j;
unsigned long t_input[2];
unsigned long t_output[2];
unsigned char *t_in_p;
unsigned long xor_0, xor_1;
t_in_p = (unsigned char *) t_input;
if (encrypt) {
#ifdef MUSTALIGN
if ((long) ivec & 3) {
memcpy((char *)&t_output[0], (char *)ivec++, sizeof(t_output[0]));
memcpy((char *)&t_output[1], (char *)ivec, sizeof(t_output[1]));
}
else
#endif
{
t_output[0] = *ivec++;
t_output[1] = *ivec;
}
for (i = 0; length > 0; i++, length -= 8) {
/* get input */
#ifdef MUSTALIGN
if ((long) input & 3) {
memcpy((char *)&t_input[0],(char *)input++,sizeof(t_input[0]));
memcpy((char *)&t_input[1],(char *)input++,sizeof(t_input[1]));
}
else
#endif
{
t_input[0] = *input++;
t_input[1] = *input++;
}
/* zero pad */
if (length < 8)
for (j = length; j <= 7; j++)
*(t_in_p+j)= 0;
#ifdef DEBUG
if (mit_des_debug)
mit_des_debug_print("clear",length,t_input[0],t_input[1]);
#endif
/* do the xor for cbc into the temp */
t_input[0] ^= t_output[0];
t_input[1] ^= t_output[1];
/* encrypt */
(void) mit_des_ecb_encrypt(t_input,t_output,key,encrypt);
/* copy temp output and save it for cbc */
#ifdef MUSTALIGN
if ((long) output & 3) {
memcpy((char *)output++,(char *)&t_output[0],
sizeof(t_output[0]));
memcpy((char *)output++,(char *)&t_output[1],
sizeof(t_output[1]));
}
else
#endif
{
*output++ = t_output[0];
*output++ = t_output[1];
}
#ifdef DEBUG
if (mit_des_debug) {
mit_des_debug_print("xor'ed",i,t_input[0],t_input[1]);
mit_des_debug_print("cipher",i,t_output[0],t_output[1]);
}
#endif
}
return 0;
}
else {
/* decrypt */
#ifdef MUSTALIGN
if ((long) ivec & 3) {
memcpy((char *)&xor_0,(char *)ivec++,sizeof(xor_0));
memcpy((char *)&xor_1,(char *)ivec,sizeof(xor_1));
}
else
#endif
{
xor_0 = *ivec++;
xor_1 = *ivec;
}
for (i = 0; length > 0; i++, length -= 8) {
/* get input */
#ifdef MUSTALIGN
if ((long) input & 3) {
memcpy((char *)&t_input[0],(char *)input++,sizeof(t_input[0]));
memcpy((char *)&t_input[1],(char *)input++,sizeof(t_input[0]));
}
else
#endif
{
t_input[0] = *input++;
t_input[1] = *input++;
}
/* no padding for decrypt */
#ifdef DEBUG
if (mit_des_debug)
mit_des_debug_print("cipher",i,t_input[0],t_input[1]);
#else
#ifdef lint
i = i;
#endif
#endif
/* encrypt */
(void) mit_des_ecb_encrypt(t_input,t_output,key,encrypt);
#ifdef DEBUG
if (mit_des_debug)
mit_des_debug_print("out pre xor",i,t_output[0],t_output[1]);
#endif
/* do the xor for cbc into the output */
t_output[0] ^= xor_0;
t_output[1] ^= xor_1;
/* copy temp output */
#ifdef MUSTALIGN
if ((long) output & 3) {
memcpy((char *)output++,(char *)&t_output[0],
sizeof(t_output[0]));
memcpy((char *)output++,(char *)&t_output[1],
sizeof(t_output[1]));
}
else
#endif
{
*output++ = t_output[0];
*output++ = t_output[1];
}
/* save xor value for next round */
xor_0 = t_input[0];
xor_1 = t_input[1];
#ifdef DEBUG
if (mit_des_debug)
mit_des_debug_print("clear",i,t_output[0],t_output[1]);
#endif
}
return 0;
}
}
|
