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
|
/* One way encryption based on MD5 sum.
Copyright (C) 1996, 1997, 1999, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* warmenhoven took this file and made it work with the md5.[ch] we
* already had. isn't that lovely. people should just use linux or
* freebsd, crypt works properly on those systems. i hate solaris */
#if HAVE_CONFIG_H
# include "config.h"
#endif
#if HAVE_STRING_H
# include <string.h>
#elif HAVE_STRINGS_H
# include <strings.h>
#endif
#include <stdlib.h>
#include "yahoo_util.h"
/* Define our magic string to mark salt for MD5 "encryption"
replacement. This is meant to be the same as for other MD5 based
encryption implementations. */
static const char md5_salt_prefix[] = "$1$";
/* Table with characters for base64 transformation. */
static const char b64t[65] =
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
char *yahoo_crypt(char *key, char *salt)
{
char *buffer = NULL;
int buflen = 0;
int needed = 3 + strlen (salt) + 1 + 26 + 1;
mir_md5_byte_t alt_result[16];
mir_md5_state_t ctx;
mir_md5_state_t alt_ctx;
int salt_len;
int key_len;
int cnt;
char *cp;
if (buflen < needed) {
buflen = needed;
if ((buffer = (char*)realloc(buffer, buflen)) == NULL)
return NULL;
}
/* Find beginning of salt string. The prefix should normally always
be present. Just in case it is not. */
if (strncmp (md5_salt_prefix, salt, sizeof (md5_salt_prefix) - 1) == 0)
/* Skip salt prefix. */
salt += sizeof (md5_salt_prefix) - 1;
salt_len = (int)MIN (strcspn (salt, "$"), 8);
key_len = (int)strlen (key);
/* Prepare for the real work. */
mir_md5_init(&ctx);
/* Add the key string. */
mir_md5_append(&ctx, (mir_md5_byte_t *)key, (int)key_len);
/* Because the SALT argument need not always have the salt prefix we
add it separately. */
mir_md5_append(&ctx, (mir_md5_byte_t *)md5_salt_prefix, sizeof (md5_salt_prefix) - 1);
/* The last part is the salt string. This must be at most 8
characters and it ends at the first `$' character (for
compatibility which existing solutions). */
mir_md5_append(&ctx, (mir_md5_byte_t *)salt, (int)salt_len);
/* Compute alternate MD5 sum with input KEY, SALT, and KEY. The
final result will be added to the first context. */
mir_md5_init(&alt_ctx);
/* Add key. */
mir_md5_append(&alt_ctx, (mir_md5_byte_t *)key, key_len);
/* Add salt. */
mir_md5_append(&alt_ctx, (mir_md5_byte_t *)salt, salt_len);
/* Add key again. */
mir_md5_append(&alt_ctx, (mir_md5_byte_t *)key, key_len);
/* Now get result of this (16 bytes) and add it to the other
context. */
mir_md5_finish(&alt_ctx, alt_result);
/* Add for any character in the key one byte of the alternate sum. */
for (cnt = key_len; cnt > 16; cnt -= 16)
mir_md5_append(&ctx, alt_result, 16);
mir_md5_append(&ctx, alt_result, cnt);
/* For the following code we need a NUL byte. */
alt_result[0] = '\0';
/* The original implementation now does something weird: for every 1
bit in the key the first 0 is added to the buffer, for every 0
bit the first character of the key. This does not seem to be
what was intended but we have to follow this to be compatible. */
for (cnt = key_len; cnt > 0; cnt >>= 1)
mir_md5_append(&ctx, (cnt & 1) != 0 ? alt_result : (mir_md5_byte_t *)key, 1);
/* Create intermediate result. */
mir_md5_finish(&ctx, alt_result);
/* Now comes another weirdness. In fear of password crackers here
comes a quite long loop which just processes the output of the
previous round again. We cannot ignore this here. */
for (cnt = 0; cnt < 1000; ++cnt) {
/* New context. */
mir_md5_init(&ctx);
/* Add key or last result. */
if ((cnt & 1) != 0)
mir_md5_append(&ctx, (mir_md5_byte_t *)key, key_len);
else
mir_md5_append(&ctx, alt_result, 16);
/* Add salt for numbers not divisible by 3. */
if (cnt % 3 != 0)
mir_md5_append(&ctx, (mir_md5_byte_t *)salt, salt_len);
/* Add key for numbers not divisible by 7. */
if (cnt % 7 != 0)
mir_md5_append(&ctx, (mir_md5_byte_t *)key, key_len);
/* Add key or last result. */
if ((cnt & 1) != 0)
mir_md5_append(&ctx, alt_result, 16);
else
mir_md5_append(&ctx, (mir_md5_byte_t *)key, key_len);
/* Create intermediate result. */
mir_md5_finish(&ctx, alt_result);
}
/* Now we can construct the result string. It consists of three
parts. */
strncpy(buffer, md5_salt_prefix, MAX (0, buflen));
cp = buffer + strlen(buffer);
buflen -= sizeof (md5_salt_prefix);
strncpy(cp, salt, MIN (buflen, salt_len));
cp = cp + strlen(cp);
buflen -= MIN (buflen, salt_len);
if (buflen > 0) {
*cp++ = '$';
--buflen;
}
#define b64_from_24bit(B2, B1, B0, N) \
do { \
unsigned int w = ((B2) << 16) | ((B1) << 8) | (B0); \
int n = (N); \
while (n-- > 0 && buflen > 0) { \
*cp++ = b64t[w & 0x3f]; \
--buflen; \
w >>= 6; \
}\
} while (0)
b64_from_24bit (alt_result[0], alt_result[6], alt_result[12], 4);
b64_from_24bit (alt_result[1], alt_result[7], alt_result[13], 4);
b64_from_24bit (alt_result[2], alt_result[8], alt_result[14], 4);
b64_from_24bit (alt_result[3], alt_result[9], alt_result[15], 4);
b64_from_24bit (alt_result[4], alt_result[10], alt_result[5], 4);
b64_from_24bit (0, 0, alt_result[11], 2);
if (buflen <= 0) {
FREE(buffer);
} else
*cp = '\0'; /* Terminate the string. */
/* Clear the buffer for the intermediate result so that people
attaching to processes or reading core dumps cannot get any
information. We do it in this way to clear correct_words[]
inside the MD5 implementation as well. */
mir_md5_init(&ctx);
mir_md5_finish(&ctx, alt_result);
memset (&ctx, '\0', sizeof (ctx));
memset (&alt_ctx, '\0', sizeof (alt_ctx));
return buffer;
}
|
