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
|
#include "includes.h"
#ifdef SKEY
RCSID("$OpenBSD: auth-skey.c,v 1.7 2000/06/20 01:39:38 markus Exp $");
#include "ssh.h"
#include "packet.h"
#include <openssl/sha.h>
/* from %OpenBSD: skeylogin.c,v 1.32 1999/08/16 14:46:56 millert Exp % */
/*
* try skey authentication,
* return 1 on success, 0 on failure, -1 if skey is not available
*/
int
auth_skey_password(struct passwd * pw, const char *password)
{
if (strncasecmp(password, "s/key", 5) == 0) {
char *skeyinfo = skey_keyinfo(pw->pw_name);
if (skeyinfo == NULL) {
debug("generating fake skeyinfo for %.100s.",
pw->pw_name);
skeyinfo = skey_fake_keyinfo(pw->pw_name);
}
if (skeyinfo != NULL)
packet_send_debug(skeyinfo);
/* Try again. */
return 0;
} else if (skey_haskey(pw->pw_name) == 0 &&
skey_passcheck(pw->pw_name, (char *) password) != -1) {
/* Authentication succeeded. */
return 1;
}
/* Fall back to ordinary passwd authentication. */
return -1;
}
/* from %OpenBSD: skeylogin.c,v 1.32 1999/08/16 14:46:56 millert Exp % */
#define ROUND(x) (((x)[0] << 24) + (((x)[1]) << 16) + (((x)[2]) << 8) + \
((x)[3]))
/*
* hash_collapse()
*/
static u_int32_t
hash_collapse(s)
u_char *s;
{
int len, target;
u_int32_t i;
if ((strlen(s) % sizeof(u_int32_t)) == 0)
target = strlen(s); /* Multiple of 4 */
else
target = strlen(s) - (strlen(s) % sizeof(u_int32_t));
for (i = 0, len = 0; len < target; len += 4)
i ^= ROUND(s + len);
return i;
}
char *
skey_fake_keyinfo(char *username)
{
int i;
u_int ptr;
u_char hseed[SKEY_MAX_SEED_LEN], flg = 1, *up;
char pbuf[SKEY_MAX_PW_LEN+1];
static char skeyprompt[SKEY_MAX_CHALLENGE+1];
char *secret = NULL;
size_t secretlen = 0;
SHA_CTX ctx;
char *p, *u;
/*
* Base first 4 chars of seed on hostname.
* Add some filler for short hostnames if necessary.
*/
if (gethostname(pbuf, sizeof(pbuf)) == -1)
*(p = pbuf) = '.';
else
for (p = pbuf; *p && isalnum(*p); p++)
if (isalpha(*p) && isupper(*p))
*p = tolower(*p);
if (*p && pbuf - p < 4)
(void)strncpy(p, "asjd", 4 - (pbuf - p));
pbuf[4] = '\0';
/* Hash the username if possible */
up = malloc(SHA_DIGEST_LENGTH);
if (up != NULL) {
struct stat sb;
time_t t;
int fd;
SHA1_Init(&ctx);
SHA1_Update(&ctx, username, strlen(username));
SHA1_Final(up, &ctx);
/* Collapse the hash */
ptr = hash_collapse(up);
memset(up, 0, strlen(up));
/* See if the random file's there, else use ctime */
if ((fd = open(_SKEY_RAND_FILE_PATH_, O_RDONLY)) != -1
&& fstat(fd, &sb) == 0 &&
sb.st_size > (off_t)SKEY_MAX_SEED_LEN &&
lseek(fd, ptr % (sb.st_size - SKEY_MAX_SEED_LEN),
SEEK_SET) != -1 && read(fd, hseed,
SKEY_MAX_SEED_LEN) == SKEY_MAX_SEED_LEN) {
close(fd);
fd = -1;
secret = hseed;
secretlen = SKEY_MAX_SEED_LEN;
flg = 0;
} else if (!stat(_PATH_MEM, &sb) || !stat("/", &sb)) {
t = sb.st_ctime;
secret = ctime(&t);
secretlen = strlen(secret);
flg = 0;
}
if (fd != -1)
close(fd);
}
/* Put that in your pipe and smoke it */
if (flg == 0) {
/* Hash secret value with username */
SHA1_Init(&ctx);
SHA1_Update(&ctx, secret, secretlen);
SHA1_Update(&ctx, username, strlen(username));
SHA1_Final(up, &ctx);
/* Zero out */
memset(secret, 0, secretlen);
/* Now hash the hash */
SHA1_Init(&ctx);
SHA1_Update(&ctx, up, strlen(up));
SHA1_Final(up, &ctx);
ptr = hash_collapse(up + 4);
for (i = 4; i < 9; i++) {
pbuf[i] = (ptr % 10) + '0';
ptr /= 10;
}
pbuf[i] = '\0';
/* Sequence number */
ptr = ((up[2] + up[3]) % 99) + 1;
memset(up, 0, SHA_DIGEST_LENGTH); /* SHA1 specific */
free(up);
(void)snprintf(skeyprompt, sizeof skeyprompt,
"otp-%.*s %d %.*s",
SKEY_MAX_HASHNAME_LEN,
skey_get_algorithm(),
ptr, SKEY_MAX_SEED_LEN,
pbuf);
} else {
/* Base last 8 chars of seed on username */
u = username;
i = 8;
p = &pbuf[4];
do {
if (*u == 0) {
/* Pad remainder with zeros */
while (--i >= 0)
*p++ = '0';
break;
}
*p++ = (*u++ % 10) + '0';
} while (--i != 0);
pbuf[12] = '\0';
(void)snprintf(skeyprompt, sizeof skeyprompt,
"otp-%.*s %d %.*s",
SKEY_MAX_HASHNAME_LEN,
skey_get_algorithm(),
99, SKEY_MAX_SEED_LEN, pbuf);
}
return skeyprompt;
}
#endif /* SKEY */
|
