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
|
/*
auth-kerberos.c
Dug Song <dugsong@UMICH.EDU>
Kerberos v4 authentication and ticket-passing routines.
$Id: auth-krb4.c,v 1.2 1999/11/08 04:49:41 damien Exp $
*/
#include "includes.h"
#include "packet.h"
#include "xmalloc.h"
#include "ssh.h"
#ifdef KRB4
int ssh_tf_init(uid_t uid)
{
extern char *ticket;
char *tkt_root = TKT_ROOT;
struct stat st;
int fd;
/* Set unique ticket string manually since we're still root. */
ticket = xmalloc(MAXPATHLEN);
#ifdef AFS
if (lstat("/ticket", &st) != -1)
tkt_root = "/ticket/";
#endif /* AFS */
snprintf(ticket, MAXPATHLEN, "%s%d_%d", tkt_root, uid, getpid());
(void) krb_set_tkt_string(ticket);
/* Make sure we own this ticket file, and we created it. */
if (lstat(ticket, &st) == -1 && errno == ENOENT) {
/* good, no ticket file exists. create it. */
if ((fd = open(ticket, O_RDWR|O_CREAT|O_EXCL, 0600)) != -1) {
close(fd);
return 1;
}
}
else {
/* file exists. make sure server_user owns it (e.g. just passed ticket),
and that it isn't a symlink, and that it is mode 600. */
if (st.st_mode == (S_IFREG|S_IRUSR|S_IWUSR) && st.st_uid == uid)
return 1;
}
/* Failure. */
log("WARNING: bad ticket file %s", ticket);
return 0;
}
int auth_krb4(const char *server_user, KTEXT auth, char **client)
{
AUTH_DAT adat = { 0 };
KTEXT_ST reply;
char instance[INST_SZ];
int r, s;
u_int cksum;
Key_schedule schedule;
struct sockaddr_in local, foreign;
s = packet_get_connection_in();
r = sizeof(local);
memset(&local, 0, sizeof(local));
if (getsockname(s, (struct sockaddr *) &local, &r) < 0)
debug("getsockname failed: %.100s", strerror(errno));
r = sizeof(foreign);
memset(&foreign, 0, sizeof(foreign));
if (getpeername(s, (struct sockaddr *)&foreign, &r) < 0)
debug("getpeername failed: %.100s", strerror(errno));
instance[0] = '*'; instance[1] = 0;
/* Get the encrypted request, challenge, and session key. */
if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, 0, &adat, ""))) {
packet_send_debug("Kerberos V4 krb_rd_req: %.100s", krb_err_txt[r]);
return 0;
}
des_key_sched((des_cblock *)adat.session, schedule);
*client = xmalloc(MAX_K_NAME_SZ);
(void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname,
*adat.pinst ? "." : "", adat.pinst, adat.prealm);
/* Check ~/.klogin authorization now. */
if (kuserok(&adat, (char *)server_user) != KSUCCESS) {
packet_send_debug("Kerberos V4 .klogin authorization failed!");
log("Kerberos V4 .klogin authorization failed for %s to account %s",
*client, server_user);
return 0;
}
/* Increment the checksum, and return it encrypted with the session key. */
cksum = adat.checksum + 1;
cksum = htonl(cksum);
/* If we can't successfully encrypt the checksum, we send back an empty
message, admitting our failure. */
if ((r = krb_mk_priv((u_char *)&cksum, reply.dat, sizeof(cksum)+1,
schedule, &adat.session, &local, &foreign)) < 0) {
packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]);
reply.dat[0] = 0;
reply.length = 0;
}
else
reply.length = r;
/* Clear session key. */
memset(&adat.session, 0, sizeof(&adat.session));
packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE);
packet_put_string((char *) reply.dat, reply.length);
packet_send();
packet_write_wait();
return 1;
}
#endif /* KRB4 */
#ifdef AFS
int auth_kerberos_tgt(struct passwd *pw, const char *string)
{
CREDENTIALS creds;
extern char *ticket;
int r;
if (!radix_to_creds(string, &creds)) {
log("Protocol error decoding Kerberos V4 tgt");
packet_send_debug("Protocol error decoding Kerberos V4 tgt");
goto auth_kerberos_tgt_failure;
}
if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
strlcpy(creds.service, "krbtgt", sizeof creds.service);
if (strcmp(creds.service, "krbtgt")) {
log("Kerberos V4 tgt (%s%s%s@%s) rejected for uid %d",
creds.pname, creds.pinst[0] ? "." : "", creds.pinst, creds.realm,
pw->pw_uid);
packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for uid %d",
creds.pname, creds.pinst[0] ? "." : "", creds.pinst,
creds.realm, pw->pw_uid);
goto auth_kerberos_tgt_failure;
}
if (!ssh_tf_init(pw->pw_uid) ||
(r = in_tkt(creds.pname, creds.pinst)) ||
(r = save_credentials(creds.service, creds.instance, creds.realm,
creds.session, creds.lifetime, creds.kvno,
&creds.ticket_st, creds.issue_date))) {
xfree(ticket);
ticket = NULL;
packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials");
goto auth_kerberos_tgt_failure;
}
/* Successful authentication, passed all checks. */
chown(ticket, pw->pw_uid, pw->pw_gid);
packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)",
creds.service, creds.instance, creds.realm,
creds.pname, creds.pinst[0] ? "." : "",
creds.pinst, creds.realm);
packet_start(SSH_SMSG_SUCCESS);
packet_send();
packet_write_wait();
return 1;
auth_kerberos_tgt_failure:
memset(&creds, 0, sizeof(creds));
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
return 0;
}
int auth_afs_token(struct passwd *pw, const char *token_string)
{
CREDENTIALS creds;
uid_t uid = pw->pw_uid;
if (!radix_to_creds(token_string, &creds)) {
log("Protocol error decoding AFS token");
packet_send_debug("Protocol error decoding AFS token");
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
return 0;
}
if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
strlcpy(creds.service, "afs", sizeof creds.service);
if (strncmp(creds.pname, "AFS ID ", 7) == 0)
uid = atoi(creds.pname + 7);
if (kafs_settoken(creds.realm, uid, &creds)) {
log("AFS token (%s@%s) rejected for uid %d", creds.pname,
creds.realm, uid);
packet_send_debug("AFS token (%s@%s) rejected for uid %d", creds.pname,
creds.realm, uid);
packet_start(SSH_SMSG_FAILURE);
packet_send();
packet_write_wait();
return 0;
}
packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service,
creds.realm, creds.pname, creds.realm);
packet_start(SSH_SMSG_SUCCESS);
packet_send();
packet_write_wait();
return 1;
}
#endif /* AFS */
|
