1 /*
2 * pppcrypt.c - PPP/DES linkage for MS-CHAP and EAP SRP-SHA1
3 *
4 * Extracted from chap_ms.c by James Carlson.
5 *
6 * Copyright (c) 1995 Eric Rosenquist. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. The name(s) of the authors of this software must not be used to
21 * endorse or promote products derived from this software without
22 * prior written permission.
23 *
24 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
25 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
26 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
27 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
28 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
29 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
30 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
31 */
32
33 #include <errno.h>
34 #include "pppd.h"
35 #include "pppcrypt.h"
36
37 static u_char
Get7Bits(input,startBit)38 Get7Bits(input, startBit)
39 u_char *input;
40 int startBit;
41 {
42 unsigned int word;
43
44 word = (unsigned)input[startBit / 8] << 8;
45 word |= (unsigned)input[startBit / 8 + 1];
46
47 word >>= 15 - (startBit % 8 + 7);
48
49 return word & 0xFE;
50 }
51
52 static void
MakeKey(key,des_key)53 MakeKey(key, des_key)
54 u_char *key; /* IN 56 bit DES key missing parity bits */
55 u_char *des_key; /* OUT 64 bit DES key with parity bits added */
56 {
57 des_key[0] = Get7Bits(key, 0);
58 des_key[1] = Get7Bits(key, 7);
59 des_key[2] = Get7Bits(key, 14);
60 des_key[3] = Get7Bits(key, 21);
61 des_key[4] = Get7Bits(key, 28);
62 des_key[5] = Get7Bits(key, 35);
63 des_key[6] = Get7Bits(key, 42);
64 des_key[7] = Get7Bits(key, 49);
65
66 #ifndef USE_CRYPT
67 des_set_odd_parity((des_cblock *)des_key);
68 #endif
69 }
70
71 #ifdef USE_CRYPT
72 /*
73 * in == 8-byte string (expanded version of the 56-bit key)
74 * out == 64-byte string where each byte is either 1 or 0
75 * Note that the low-order "bit" is always ignored by by setkey()
76 */
77 static void
Expand(in,out)78 Expand(in, out)
79 u_char *in;
80 u_char *out;
81 {
82 int j, c;
83 int i;
84
85 for (i = 0; i < 64; in++){
86 c = *in;
87 for (j = 7; j >= 0; j--)
88 *out++ = (c >> j) & 01;
89 i += 8;
90 }
91 }
92
93 /* The inverse of Expand
94 */
95 static void
Collapse(in,out)96 Collapse(in, out)
97 u_char *in;
98 u_char *out;
99 {
100 int j;
101 int i;
102 unsigned int c;
103
104 for (i = 0; i < 64; i += 8, out++) {
105 c = 0;
106 for (j = 7; j >= 0; j--, in++)
107 c |= *in << j;
108 *out = c & 0xff;
109 }
110 }
111
112 bool
DesSetkey(key)113 DesSetkey(key)
114 u_char *key;
115 {
116 u_char des_key[8];
117 u_char crypt_key[66];
118
119 MakeKey(key, des_key);
120 Expand(des_key, crypt_key);
121 errno = 0;
122 setkey((const char *)crypt_key);
123 if (errno != 0)
124 return (0);
125 return (1);
126 }
127
128 bool
DesEncrypt(clear,cipher)129 DesEncrypt(clear, cipher)
130 u_char *clear; /* IN 8 octets */
131 u_char *cipher; /* OUT 8 octets */
132 {
133 u_char des_input[66];
134
135 Expand(clear, des_input);
136 errno = 0;
137 encrypt((char *)des_input, 0);
138 if (errno != 0)
139 return (0);
140 Collapse(des_input, cipher);
141 return (1);
142 }
143
144 bool
DesDecrypt(cipher,clear)145 DesDecrypt(cipher, clear)
146 u_char *cipher; /* IN 8 octets */
147 u_char *clear; /* OUT 8 octets */
148 {
149 u_char des_input[66];
150
151 Expand(cipher, des_input);
152 errno = 0;
153 encrypt((char *)des_input, 1);
154 if (errno != 0)
155 return (0);
156 Collapse(des_input, clear);
157 return (1);
158 }
159
160 #else /* USE_CRYPT */
161 static des_key_schedule key_schedule;
162
163 bool
DesSetkey(key)164 DesSetkey(key)
165 u_char *key;
166 {
167 des_cblock des_key;
168 MakeKey(key, des_key);
169 des_set_key(&des_key, key_schedule);
170 return (1);
171 }
172
173 bool
DesEncrypt(clear,cipher)174 DesEncrypt(clear, cipher)
175 u_char *clear; /* IN 8 octets */
176 u_char *cipher; /* OUT 8 octets */
177 {
178 des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher,
179 key_schedule, 1);
180 return (1);
181 }
182
183 bool
DesDecrypt(cipher,clear)184 DesDecrypt(cipher, clear)
185 u_char *cipher; /* IN 8 octets */
186 u_char *clear; /* OUT 8 octets */
187 {
188 des_ecb_encrypt((des_cblock *)cipher, (des_cblock *)clear,
189 key_schedule, 0);
190 return (1);
191 }
192
193 #endif /* USE_CRYPT */
194