2 * Copyright (c) 1999 Dug Song. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 RCSID("$OpenBSD: auth-krb4.c,v 1.23 2001/01/22 08:15:00 markus Exp $");
43 extern ServerOptions options;
46 * try krb4 authentication,
47 * return 1 on success, 0 on failure, -1 if krb4 is not available
51 auth_krb4_password(struct passwd * pw, const char *password)
57 char localhost[MAXHOSTNAMELEN];
63 * Try Kerberos password authentication only for non-root
64 * users and only if Kerberos is installed.
66 if (pw->pw_uid != 0 && krb_get_lrealm(realm, 1) == KSUCCESS) {
68 /* Set up our ticket file. */
69 if (!krb4_init(pw->pw_uid)) {
70 log("Couldn't initialize Kerberos ticket file for %s!",
72 goto kerberos_auth_failure;
74 /* Try to get TGT using our password. */
75 r = krb_get_pw_in_tkt((char *) pw->pw_name, "",
76 realm, "krbtgt", realm,
77 DEFAULT_TKT_LIFE, (char *) password);
79 packet_send_debug("Kerberos V4 password "
80 "authentication for %s failed: %s",
81 pw->pw_name, krb_err_txt[r]);
82 goto kerberos_auth_failure;
84 /* Successful authentication. */
85 chown(tkt_string(), pw->pw_uid, pw->pw_gid);
88 * Now that we have a TGT, try to get a local
89 * "rcmd" ticket to ensure that we are not talking
90 * to a bogus Kerberos server.
92 (void) gethostname(localhost, sizeof(localhost));
93 (void) strlcpy(phost, (char *) krb_get_phost(localhost),
95 r = krb_mk_req(&tkt, KRB4_SERVICE_NAME, phost, realm, 33);
98 if (!(hp = gethostbyname(localhost))) {
99 log("Couldn't get local host address!");
100 goto kerberos_auth_failure;
102 memmove((void *) &faddr, (void *) hp->h_addr,
105 /* Verify our "rcmd" ticket. */
106 r = krb_rd_req(&tkt, KRB4_SERVICE_NAME, phost,
108 if (r == RD_AP_UNDEC) {
110 * Probably didn't have a srvtab on
111 * localhost. Disallow login.
113 log("Kerberos V4 TGT for %s unverifiable, "
114 "no srvtab installed? krb_rd_req: %s",
115 pw->pw_name, krb_err_txt[r]);
116 goto kerberos_auth_failure;
117 } else if (r != KSUCCESS) {
118 log("Kerberos V4 %s ticket unverifiable: %s",
119 KRB4_SERVICE_NAME, krb_err_txt[r]);
120 goto kerberos_auth_failure;
122 } else if (r == KDC_PR_UNKNOWN) {
124 * Disallow login if no rcmd service exists, and
127 log("Kerberos V4 TGT for %s unverifiable: %s; %s.%s "
128 "not registered, or srvtab is wrong?", pw->pw_name,
129 krb_err_txt[r], KRB4_SERVICE_NAME, phost);
130 goto kerberos_auth_failure;
133 * TGT is bad, forget it. Possibly spoofed!
135 packet_send_debug("WARNING: Kerberos V4 TGT "
136 "possibly spoofed for %s: %s",
137 pw->pw_name, krb_err_txt[r]);
138 goto kerberos_auth_failure;
141 /* Authentication succeeded. */
144 kerberos_auth_failure:
145 krb4_cleanup_proc(NULL);
147 if (!options.kerberos_or_local_passwd)
150 /* Logging in as root or no local Kerberos realm. */
151 packet_send_debug("Unable to authenticate to Kerberos.");
153 /* Fall back to ordinary passwd authentication. */
158 krb4_cleanup_proc(void *ignore)
160 debug("krb4_cleanup_proc called");
171 static int cleanup_registered = 0;
172 const char *tkt_root = TKT_ROOT;
177 /* Set unique ticket string manually since we're still root. */
178 ticket = xmalloc(MAXPATHLEN);
180 if (lstat("/ticket", &st) != -1)
181 tkt_root = "/ticket/";
183 snprintf(ticket, MAXPATHLEN, "%s%u_%d", tkt_root, uid, getpid());
184 (void) krb_set_tkt_string(ticket);
186 /* Register ticket cleanup in case of fatal error. */
187 if (!cleanup_registered) {
188 fatal_add_cleanup(krb4_cleanup_proc, NULL);
189 cleanup_registered = 1;
191 /* Try to create our ticket file. */
192 if ((fd = mkstemp(ticket)) != -1) {
196 /* Ticket file exists - make sure user owns it (just passed ticket). */
197 if (lstat(ticket, &st) != -1) {
198 if (st.st_mode == (S_IFREG | S_IRUSR | S_IWUSR) &&
202 /* Failure - cancel cleanup function, leaving bad ticket for inspection. */
203 log("WARNING: bad ticket file %s", ticket);
204 fatal_remove_cleanup(krb4_cleanup_proc, NULL);
205 cleanup_registered = 0;
213 auth_krb4(const char *server_user, KTEXT auth, char **client)
217 char instance[INST_SZ];
221 Key_schedule schedule;
222 struct sockaddr_in local, foreign;
224 s = packet_get_connection_in();
226 slen = sizeof(local);
227 memset(&local, 0, sizeof(local));
228 if (getsockname(s, (struct sockaddr *) & local, &slen) < 0)
229 debug("getsockname failed: %.100s", strerror(errno));
230 slen = sizeof(foreign);
231 memset(&foreign, 0, sizeof(foreign));
232 if (getpeername(s, (struct sockaddr *) & foreign, &slen) < 0) {
233 debug("getpeername failed: %.100s", strerror(errno));
239 /* Get the encrypted request, challenge, and session key. */
240 if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, 0, &adat, ""))) {
241 packet_send_debug("Kerberos V4 krb_rd_req: %.100s", krb_err_txt[r]);
244 des_key_sched((des_cblock *) adat.session, schedule);
246 *client = xmalloc(MAX_K_NAME_SZ);
247 (void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname,
248 *adat.pinst ? "." : "", adat.pinst, adat.prealm);
250 /* Check ~/.klogin authorization now. */
251 if (kuserok(&adat, (char *) server_user) != KSUCCESS) {
252 packet_send_debug("Kerberos V4 .klogin authorization failed!");
253 log("Kerberos V4 .klogin authorization failed for %s to account %s",
254 *client, server_user);
258 /* Increment the checksum, and return it encrypted with the
260 cksum = adat.checksum + 1;
261 cksum = htonl(cksum);
263 /* If we can't successfully encrypt the checksum, we send back an
264 empty message, admitting our failure. */
265 if ((r = krb_mk_priv((u_char *) & cksum, reply.dat, sizeof(cksum) + 1,
266 schedule, &adat.session, &local, &foreign)) < 0) {
267 packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]);
273 /* Clear session key. */
274 memset(&adat.session, 0, sizeof(&adat.session));
276 packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE);
277 packet_put_string((char *) reply.dat, reply.length);
286 auth_kerberos_tgt(struct passwd *pw, const char *string)
291 goto auth_kerberos_tgt_failure;
292 if (!radix_to_creds(string, &creds)) {
293 log("Protocol error decoding Kerberos V4 tgt");
294 packet_send_debug("Protocol error decoding Kerberos V4 tgt");
295 goto auth_kerberos_tgt_failure;
297 if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
298 strlcpy(creds.service, "krbtgt", sizeof creds.service);
300 if (strcmp(creds.service, "krbtgt")) {
301 log("Kerberos V4 tgt (%s%s%s@%s) rejected for %s", creds.pname,
302 creds.pinst[0] ? "." : "", creds.pinst, creds.realm,
304 packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for %s",
305 creds.pname, creds.pinst[0] ? "." : "", creds.pinst,
306 creds.realm, pw->pw_name);
307 goto auth_kerberos_tgt_failure;
309 if (!krb4_init(pw->pw_uid))
310 goto auth_kerberos_tgt_failure;
312 if (in_tkt(creds.pname, creds.pinst) != KSUCCESS)
313 goto auth_kerberos_tgt_failure;
315 if (save_credentials(creds.service, creds.instance, creds.realm,
316 creds.session, creds.lifetime, creds.kvno,
317 &creds.ticket_st, creds.issue_date) != KSUCCESS) {
318 packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials");
319 goto auth_kerberos_tgt_failure;
321 /* Successful authentication, passed all checks. */
322 chown(tkt_string(), pw->pw_uid, pw->pw_gid);
324 packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)",
325 creds.service, creds.instance, creds.realm, creds.pname,
326 creds.pinst[0] ? "." : "", creds.pinst, creds.realm);
327 memset(&creds, 0, sizeof(creds));
328 packet_start(SSH_SMSG_SUCCESS);
333 auth_kerberos_tgt_failure:
334 krb4_cleanup_proc(NULL);
335 memset(&creds, 0, sizeof(creds));
336 packet_start(SSH_SMSG_FAILURE);
343 auth_afs_token(struct passwd *pw, const char *token_string)
349 /* XXX fake protocol error */
350 packet_send_debug("Protocol error decoding AFS token");
351 packet_start(SSH_SMSG_FAILURE);
356 if (!radix_to_creds(token_string, &creds)) {
357 log("Protocol error decoding AFS token");
358 packet_send_debug("Protocol error decoding AFS token");
359 packet_start(SSH_SMSG_FAILURE);
364 if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
365 strlcpy(creds.service, "afs", sizeof creds.service);
367 if (strncmp(creds.pname, "AFS ID ", 7) == 0)
368 uid = atoi(creds.pname + 7);
372 if (kafs_settoken(creds.realm, uid, &creds)) {
373 log("AFS token (%s@%s) rejected for %s", creds.pname, creds.realm,
375 packet_send_debug("AFS token (%s@%s) rejected for %s", creds.pname,
376 creds.realm, pw->pw_name);
377 memset(&creds, 0, sizeof(creds));
378 packet_start(SSH_SMSG_FAILURE);
383 packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service,
384 creds.realm, creds.pname, creds.realm);
385 memset(&creds, 0, sizeof(creds));
386 packet_start(SSH_SMSG_SUCCESS);