1 /*
2  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 
7 /*
8  * kdc/do_tgs_req.c
9  *
10  * Copyright 1990,1991,2001 by the Massachusetts Institute of Technology.
11  * All Rights Reserved.
12  *
13  * Export of this software from the United States of America may
14  *   require a specific license from the United States Government.
15  *   It is the responsibility of any person or organization contemplating
16  *   export to obtain such a license before exporting.
17  *
18  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
19  * distribute this software and its documentation for any purpose and
20  * without fee is hereby granted, provided that the above copyright
21  * notice appear in all copies and that both that copyright notice and
22  * this permission notice appear in supporting documentation, and that
23  * the name of M.I.T. not be used in advertising or publicity pertaining
24  * to distribution of the software without specific, written prior
25  * permission.  Furthermore if you modify this software you must label
26  * your software as modified software and not distribute it in such a
27  * fashion that it might be confused with the original M.I.T. software.
28  * M.I.T. makes no representations about the suitability of
29  * this software for any purpose.  It is provided "as is" without express
30  * or implied warranty.
31  *
32  *
33  * KDC Routines to deal with TGS_REQ's
34  */
35 
36 #include "k5-int.h"
37 #include "com_err.h"
38 
39 #include <syslog.h>
40 #ifdef HAVE_NETINET_IN_H
41 #include <sys/types.h>
42 #include <netinet/in.h>
43 #ifndef hpux
44 #include <arpa/inet.h>
45 #endif
46 #endif
47 
48 #include "kdc_util.h"
49 #include "policy.h"
50 #include "extern.h"
51 #include "adm_proto.h"
52 
53 extern krb5_error_code setup_server_realm(krb5_principal);
54 
55 static void find_alternate_tgs (krb5_kdc_req *, krb5_db_entry *,
56 				krb5_boolean *, int *,
57 		   		const krb5_fulladdr *from, char *cname);
58 
59 static krb5_error_code prepare_error_tgs (krb5_kdc_req *, krb5_ticket *,
60 					  int, const char *, krb5_data **,
61 					  const char *);
62 
63 /*ARGSUSED*/
64 krb5_error_code
65 process_tgs_req(krb5_data *pkt, const krb5_fulladdr *from,
66 		krb5_data **response)
67 {
68     krb5_keyblock * subkey;
69     krb5_kdc_req *request = 0;
70     krb5_db_entry server;
71     krb5_kdc_rep reply;
72     krb5_enc_kdc_rep_part reply_encpart;
73     krb5_ticket ticket_reply, *header_ticket = 0;
74     int st_idx = 0;
75     krb5_enc_tkt_part enc_tkt_reply;
76     krb5_transited enc_tkt_transited;
77     int newtransited = 0;
78     krb5_error_code retval = 0;
79     int nprincs = 0;
80     krb5_boolean more;
81     krb5_timestamp kdc_time, authtime=0;
82     krb5_keyblock session_key;
83     krb5_timestamp until, rtime;
84     krb5_keyblock encrypting_key;
85     krb5_key_data  *server_key;
86     char *cname = 0, *sname = 0, *tmp = 0;
87     const char *fromstring = 0;
88     krb5_last_req_entry *nolrarray[2], nolrentry;
89 /*    krb5_address *noaddrarray[1]; */
90     krb5_enctype useenctype;
91     int	errcode, errcode2;
92     register int i;
93     int firstpass = 1;
94     const char	*status = 0;
95     char ktypestr[128];
96     char rep_etypestr[128];
97     char fromstringbuf[70];
98     long long tmp_server_times, tmp_realm_times;
99 
100     (void) memset(&encrypting_key, 0, sizeof(krb5_keyblock));
101     (void) memset(&session_key, 0, sizeof(krb5_keyblock));
102 
103     retval = decode_krb5_tgs_req(pkt, &request);
104     if (retval)
105 	return retval;
106 
107     ktypes2str(ktypestr, sizeof(ktypestr),
108 	       request->nktypes, request->ktype);
109     /*
110      * setup_server_realm() sets up the global realm-specific data pointer.
111      */
112     if ((retval = setup_server_realm(request->server)))
113 	return retval;
114 
115     fromstring = inet_ntop(ADDRTYPE2FAMILY(from->address->addrtype),
116 			   from->address->contents,
117 			   fromstringbuf, sizeof(fromstringbuf));
118     if (!fromstring)
119 	fromstring = "<unknown>";
120 
121     if ((errcode = krb5_unparse_name(kdc_context, request->server, &sname))) {
122 	status = "UNPARSING SERVER";
123 	goto cleanup;
124     }
125     limit_string(sname);
126 
127    /* errcode = kdc_process_tgs_req(request, from, pkt, &req_authdat); */
128     errcode = kdc_process_tgs_req(request, from, pkt, &header_ticket, &subkey);
129 
130     if (header_ticket && header_ticket->enc_part2 &&
131 	(errcode2 = krb5_unparse_name(kdc_context,
132 				      header_ticket->enc_part2->client,
133 				      &cname))) {
134 	status = "UNPARSING CLIENT";
135 	errcode = errcode2;
136 	goto cleanup;
137     }
138     limit_string(cname);
139 
140     if (errcode) {
141 	status = "PROCESS_TGS";
142 	goto cleanup;
143     }
144 
145     if (!header_ticket) {
146 	errcode = KRB5_NO_TKT_SUPPLIED;	/* XXX? */
147 	status="UNEXPECTED NULL in header_ticket";
148 	goto cleanup;
149     }
150 
151     /*
152      * We've already dealt with the AP_REQ authentication, so we can
153      * use header_ticket freely.  The encrypted part (if any) has been
154      * decrypted with the session key.
155      */
156 
157     authtime = header_ticket->enc_part2->times.authtime;
158 
159     /* XXX make sure server here has the proper realm...taken from AP_REQ
160        header? */
161 
162     nprincs = 1;
163     if ((errcode = krb5_db_get_principal(kdc_context, request->server, &server,
164 					&nprincs, &more))) {
165 	status = "LOOKING_UP_SERVER";
166 	nprincs = 0;
167 	goto cleanup;
168     }
169 tgt_again:
170     if (more) {
171 	status = "NON_UNIQUE_PRINCIPAL";
172 	errcode = KRB5KDC_ERR_PRINCIPAL_NOT_UNIQUE;
173 	goto cleanup;
174     } else if (nprincs != 1) {
175 	/*
176 	 * might be a request for a TGT for some other realm; we
177 	 * should do our best to find such a TGS in this db
178 	 */
179 	if (firstpass && krb5_is_tgs_principal(request->server) == TRUE) {
180 	    if (krb5_princ_size(kdc_context, request->server) == 2) {
181 		krb5_data *server_1 =
182 		    krb5_princ_component(kdc_context, request->server, 1);
183 		krb5_data *tgs_1 =
184 		    krb5_princ_component(kdc_context, tgs_server, 1);
185 
186 		if (!tgs_1 || server_1->length != tgs_1->length ||
187 		    memcmp(server_1->data, tgs_1->data, tgs_1->length)) {
188 		    krb5_db_free_principal(kdc_context, &server, nprincs);
189 		    find_alternate_tgs(request, &server, &more, &nprincs,
190 				      from, cname);
191 		    firstpass = 0;
192 		    goto tgt_again;
193 		}
194 	    }
195 	}
196 	krb5_db_free_principal(kdc_context, &server, nprincs);
197 	status = "UNKNOWN_SERVER";
198 	errcode = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
199 	goto cleanup;
200     }
201 
202     if ((errcode = krb5_timeofday(kdc_context, &kdc_time))) {
203 	status = "TIME_OF_DAY";
204 	goto cleanup;
205     }
206 
207     if ((retval = validate_tgs_request(request, server, header_ticket,
208 				      kdc_time, &status))) {
209 	if (!status)
210 	    status = "UNKNOWN_REASON";
211 	errcode = retval + ERROR_TABLE_BASE_krb5;
212 	goto cleanup;
213     }
214 
215     /*
216      * We pick the session keytype here....
217      *
218      * Some special care needs to be taken in the user-to-user
219      * case, since we don't know what keytypes the application server
220      * which is doing user-to-user authentication can support.  We
221      * know that it at least must be able to support the encryption
222      * type of the session key in the TGT, since otherwise it won't be
223      * able to decrypt the U2U ticket!  So we use that in preference
224      * to anything else.
225      */
226     useenctype = 0;
227     if (isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) {
228 	krb5_keyblock *	st_sealing_key;
229 	krb5_kvno 	st_srv_kvno;
230 	krb5_enctype	etype;
231 
232 	/*
233 	 * Get the key for the second ticket, and decrypt it.
234 	 */
235 	if ((errcode = kdc_get_server_key(request->second_ticket[st_idx],
236 					 &st_sealing_key,
237 					 &st_srv_kvno))) {
238 	    status = "2ND_TKT_SERVER";
239 	    goto cleanup;
240 	}
241 	errcode = krb5_decrypt_tkt_part(kdc_context, st_sealing_key,
242 				       request->second_ticket[st_idx]);
243 	krb5_free_keyblock(kdc_context, st_sealing_key);
244 	if (errcode) {
245 	    status = "2ND_TKT_DECRYPT";
246 	    goto cleanup;
247 	}
248 
249 	etype = request->second_ticket[st_idx]->enc_part2->session->enctype;
250 	if (!krb5_c_valid_enctype(etype)) {
251 	    status = "BAD_ETYPE_IN_2ND_TKT";
252 	    errcode = KRB5KDC_ERR_ETYPE_NOSUPP;
253 	    goto cleanup;
254 	}
255 
256 	for (i = 0; i < request->nktypes; i++) {
257 	    if (request->ktype[i] == etype) {
258 		useenctype = etype;
259 		break;
260 	    }
261 	}
262     }
263 
264     /*
265      * Select the keytype for the ticket session key.
266      */
267     if ((useenctype == 0) &&
268 	(useenctype = select_session_keytype(kdc_context, &server,
269 					     request->nktypes,
270 					     request->ktype)) == 0) {
271 	/* unsupported ktype */
272 	status = "BAD_ENCRYPTION_TYPE";
273 	errcode = KRB5KDC_ERR_ETYPE_NOSUPP;
274 	goto cleanup;
275     }
276 
277     errcode = krb5_c_make_random_key(kdc_context, useenctype, &session_key);
278 
279     if (errcode) {
280 	/* random key failed */
281 	status = "RANDOM_KEY_FAILED";
282 	goto cleanup;
283     }
284 
285     ticket_reply.server = request->server; /* XXX careful for realm... */
286 
287     enc_tkt_reply.flags = 0;
288     enc_tkt_reply.times.starttime = 0;
289 
290     /*
291      * Fix header_ticket's starttime; if it's zero, fill in the
292      * authtime's value.
293      */
294     if (!(header_ticket->enc_part2->times.starttime))
295 	header_ticket->enc_part2->times.starttime =
296 	    header_ticket->enc_part2->times.authtime;
297 
298     /* don't use new addresses unless forwarded, see below */
299 
300     enc_tkt_reply.caddrs = header_ticket->enc_part2->caddrs;
301     /* noaddrarray[0] = 0; */
302     reply_encpart.caddrs = 0;		/* optional...don't put it in */
303 
304     /* It should be noted that local policy may affect the  */
305     /* processing of any of these flags.  For example, some */
306     /* realms may refuse to issue renewable tickets         */
307 
308     if (isflagset(request->kdc_options, KDC_OPT_FORWARDABLE))
309 	setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDABLE);
310 
311     if (isflagset(request->kdc_options, KDC_OPT_FORWARDED)) {
312 	setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDED);
313 
314 	/* include new addresses in ticket & reply */
315 
316 	enc_tkt_reply.caddrs = request->addresses;
317 	reply_encpart.caddrs = request->addresses;
318     }
319     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_FORWARDED))
320 	setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDED);
321 
322     if (isflagset(request->kdc_options, KDC_OPT_PROXIABLE))
323 	setflag(enc_tkt_reply.flags, TKT_FLG_PROXIABLE);
324 
325     if (isflagset(request->kdc_options, KDC_OPT_PROXY)) {
326 	setflag(enc_tkt_reply.flags, TKT_FLG_PROXY);
327 
328 	/* include new addresses in ticket & reply */
329 
330 	enc_tkt_reply.caddrs = request->addresses;
331 	reply_encpart.caddrs = request->addresses;
332     }
333 
334     if (isflagset(request->kdc_options, KDC_OPT_ALLOW_POSTDATE))
335 	setflag(enc_tkt_reply.flags, TKT_FLG_MAY_POSTDATE);
336 
337     if (isflagset(request->kdc_options, KDC_OPT_POSTDATED)) {
338 	setflag(enc_tkt_reply.flags, TKT_FLG_POSTDATED);
339 	setflag(enc_tkt_reply.flags, TKT_FLG_INVALID);
340 	enc_tkt_reply.times.starttime = request->from;
341     } else
342 	enc_tkt_reply.times.starttime = kdc_time;
343 
344     if (isflagset(request->kdc_options, KDC_OPT_VALIDATE)) {
345 	/* BEWARE of allocation hanging off of ticket & enc_part2, it belongs
346 	   to the caller */
347 	ticket_reply = *(header_ticket);
348 	enc_tkt_reply = *(header_ticket->enc_part2);
349 	clear(enc_tkt_reply.flags, TKT_FLG_INVALID);
350     }
351 
352     if (isflagset(request->kdc_options, KDC_OPT_RENEW)) {
353 	krb5_deltat old_life;
354 
355 	/* BEWARE of allocation hanging off of ticket & enc_part2, it belongs
356 	   to the caller */
357 	ticket_reply = *(header_ticket);
358 	enc_tkt_reply = *(header_ticket->enc_part2);
359 
360 	old_life = enc_tkt_reply.times.endtime - enc_tkt_reply.times.starttime;
361 
362 	enc_tkt_reply.times.starttime = kdc_time;
363 	enc_tkt_reply.times.endtime =
364 	    min(header_ticket->enc_part2->times.renew_till,
365 		kdc_time + old_life);
366     } else {
367 	/* not a renew request */
368 	enc_tkt_reply.times.starttime = kdc_time;
369 	until = (request->till == 0) ? kdc_infinity : request->till;
370 
371 	/* SUNW */
372         tmp_server_times = (long long) enc_tkt_reply.times.starttime
373 	  + server.max_life;
374 
375         tmp_realm_times = (long long) enc_tkt_reply.times.starttime
376 	  + max_life_for_realm;
377 
378         enc_tkt_reply.times.endtime =
379   	  min(until,
380 	    min(tmp_server_times,
381 		min(tmp_realm_times,
382 			min(header_ticket->enc_part2->times.endtime,
383 			    KRB5_KDB_EXPIRATION)))); /* SUNW */
384 /*
385 	enc_tkt_reply.times.endtime =
386 	    min(until, min(enc_tkt_reply.times.starttime + server.max_life,
387 			   min(enc_tkt_reply.times.starttime + max_life_for_realm,
388 			       min(header_ticket->enc_part2->times.endtime)));
389 */
390 	if (isflagset(request->kdc_options, KDC_OPT_RENEWABLE_OK) &&
391 	    (enc_tkt_reply.times.endtime < request->till) &&
392 	    isflagset(header_ticket->enc_part2->flags,
393 		  TKT_FLG_RENEWABLE)) {
394 	    setflag(request->kdc_options, KDC_OPT_RENEWABLE);
395 	    request->rtime =
396 		min(request->till,
397 		    min(KRB5_KDB_EXPIRATION,
398 		    header_ticket->enc_part2->times.renew_till));
399 	}
400     }
401     rtime = (request->rtime == 0) ? kdc_infinity : request->rtime;
402 
403     if (isflagset(request->kdc_options, KDC_OPT_RENEWABLE)) {
404 	/* already checked above in policy check to reject request for a
405 	   renewable ticket using a non-renewable ticket */
406 	setflag(enc_tkt_reply.flags, TKT_FLG_RENEWABLE);
407 	tmp_realm_times =  (long long) enc_tkt_reply.times.starttime +
408 		min(server.max_renewable_life,max_renewable_life_for_realm);
409 	enc_tkt_reply.times.renew_till =
410 	    min(rtime,
411 		min(header_ticket->enc_part2->times.renew_till,
412 				min (tmp_realm_times, KRB5_KDB_EXPIRATION)));
413     } else {
414 	enc_tkt_reply.times.renew_till = 0;
415     }
416 
417     /*
418      * Set authtime to be the same as header_ticket's
419      */
420     enc_tkt_reply.times.authtime = header_ticket->enc_part2->times.authtime;
421 
422     /*
423      * Propagate the preauthentication flags through to the returned ticket.
424      */
425     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_PRE_AUTH))
426 	setflag(enc_tkt_reply.flags, TKT_FLG_PRE_AUTH);
427 
428     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_HW_AUTH))
429 	setflag(enc_tkt_reply.flags, TKT_FLG_HW_AUTH);
430 
431     /* starttime is optional, and treated as authtime if not present.
432        so we can nuke it if it matches */
433     if (enc_tkt_reply.times.starttime == enc_tkt_reply.times.authtime)
434 	enc_tkt_reply.times.starttime = 0;
435 
436     /* assemble any authorization data */
437     if (request->authorization_data.ciphertext.data) {
438 	krb5_data scratch;
439 
440 	scratch.length = request->authorization_data.ciphertext.length;
441 	if (!(scratch.data =
442 	      malloc(request->authorization_data.ciphertext.length))) {
443 	    status = "AUTH_NOMEM";
444 	    errcode = ENOMEM;
445 	    goto cleanup;
446 	}
447 
448 	if ((errcode = krb5_c_decrypt(kdc_context,
449 				      header_ticket->enc_part2->session,
450 				      KRB5_KEYUSAGE_TGS_REQ_AD_SESSKEY,
451 				      0, &request->authorization_data,
452 				      &scratch))) {
453 	    status = "AUTH_ENCRYPT_FAIL";
454 	    free(scratch.data);
455 	    goto cleanup;
456 	}
457 
458 	/* scratch now has the authorization data, so we decode it */
459 	errcode = decode_krb5_authdata(&scratch, &(request->unenc_authdata));
460 	free(scratch.data);
461 	if (errcode) {
462 	    status = "AUTH_DECODE";
463 	    goto cleanup;
464 	}
465 
466 	if ((errcode =
467 	     concat_authorization_data(request->unenc_authdata,
468 				       header_ticket->enc_part2->authorization_data,
469 				       &enc_tkt_reply.authorization_data))) {
470 	    status = "CONCAT_AUTH";
471 	    goto cleanup;
472 	}
473     } else
474 	enc_tkt_reply.authorization_data =
475 	    header_ticket->enc_part2->authorization_data;
476 
477     enc_tkt_reply.session = &session_key;
478     enc_tkt_reply.client = header_ticket->enc_part2->client;
479     enc_tkt_reply.transited.tr_type = KRB5_DOMAIN_X500_COMPRESS;
480     enc_tkt_reply.transited.tr_contents = empty_string; /* equivalent of "" */
481 
482     /*
483      * Only add the realm of the presented tgt to the transited list if
484      * it is different than the local realm (cross-realm) and it is different
485      * than the realm of the client (since the realm of the client is already
486      * implicitly part of the transited list and should not be explicitly
487      * listed).
488      */
489 
490     /* realm compare is like strcmp, but knows how to deal with these args */
491     if (realm_compare(header_ticket->server, tgs_server) ||
492 	realm_compare(header_ticket->server, enc_tkt_reply.client)) {
493 	/* tgt issued by local realm or issued by realm of client */
494 	enc_tkt_reply.transited = header_ticket->enc_part2->transited;
495     } else {
496 	/* tgt issued by some other realm and not the realm of the client */
497 	/* assemble new transited field into allocated storage */
498 	if (header_ticket->enc_part2->transited.tr_type !=
499 	    KRB5_DOMAIN_X500_COMPRESS) {
500 	    status = "BAD_TRTYPE";
501 	    errcode = KRB5KDC_ERR_TRTYPE_NOSUPP;
502 	    goto cleanup;
503 	}
504 	enc_tkt_transited.tr_type = KRB5_DOMAIN_X500_COMPRESS;
505 	enc_tkt_transited.magic = 0;
506 	enc_tkt_transited.tr_contents.magic = 0;
507 	enc_tkt_transited.tr_contents.data = 0;
508 	enc_tkt_transited.tr_contents.length = 0;
509 	enc_tkt_reply.transited = enc_tkt_transited;
510 	if ((errcode =
511 	     add_to_transited(&header_ticket->enc_part2->transited.tr_contents,
512 			      &enc_tkt_reply.transited.tr_contents,
513 			      header_ticket->server,
514 			      enc_tkt_reply.client,
515 			      request->server))) {
516 	    status = "ADD_TR_FAIL";
517 	    goto cleanup;
518 	}
519 	newtransited = 1;
520     }
521     if (!isflagset (request->kdc_options, KDC_OPT_DISABLE_TRANSITED_CHECK)) {
522 	unsigned int tlen;
523 	char *tdots;
524 
525 	errcode = krb5_check_transited_list (kdc_context,
526 					     &enc_tkt_reply.transited.tr_contents,
527 					     krb5_princ_realm (kdc_context, header_ticket->enc_part2->client),
528 					     krb5_princ_realm (kdc_context, request->server));
529 	tlen = enc_tkt_reply.transited.tr_contents.length;
530 	tdots = tlen > 125 ? "..." : "";
531 	tlen = tlen > 125 ? 125 : tlen;
532 
533 	if (errcode == 0) {
534 	    setflag (enc_tkt_reply.flags, TKT_FLG_TRANSIT_POLICY_CHECKED);
535 	} else if (errcode == KRB5KRB_AP_ERR_ILL_CR_TKT)
536 	    krb5_klog_syslog (LOG_INFO,
537 			      "bad realm transit path from '%s' to '%s' "
538 			      "via '%.*s%s'",
539 			      cname ? cname : "<unknown client>",
540 			      sname ? sname : "<unknown server>",
541 			      tlen,
542 			      enc_tkt_reply.transited.tr_contents.data,
543 			      tdots);
544 	else {
545 	    const char *emsg = krb5_get_error_message(kdc_context, errcode);
546 	    krb5_klog_syslog (LOG_ERR,
547 			      "unexpected error checking transit from "
548 			      "'%s' to '%s' via '%.*s%s': %s",
549 			      cname ? cname : "<unknown client>",
550 			      sname ? sname : "<unknown server>",
551 			      tlen,
552 			      enc_tkt_reply.transited.tr_contents.data,
553 			      tdots, emsg);
554 	    krb5_free_error_message(kdc_context, emsg);
555 	}
556     } else
557 	krb5_klog_syslog (LOG_INFO, "not checking transit path");
558     if (reject_bad_transit
559 	&& !isflagset (enc_tkt_reply.flags, TKT_FLG_TRANSIT_POLICY_CHECKED)) {
560 	errcode = KRB5KDC_ERR_POLICY;
561 	status = "BAD_TRANSIT";
562 	goto cleanup;
563     }
564 
565     ticket_reply.enc_part2 = &enc_tkt_reply;
566 
567     /*
568      * If we are doing user-to-user authentication, then make sure
569      * that the client for the second ticket matches the request
570      * server, and then encrypt the ticket using the session key of
571      * the second ticket.
572      */
573     if (isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) {
574 	/*
575 	 * Make sure the client for the second ticket matches
576 	 * requested server.
577 	 */
578 	krb5_enc_tkt_part *t2enc = request->second_ticket[st_idx]->enc_part2;
579 	krb5_principal client2 = t2enc->client;
580 	if (!krb5_principal_compare(kdc_context, request->server, client2)) {
581 		if ((errcode = krb5_unparse_name(kdc_context, client2, &tmp)))
582 			tmp = 0;
583 		if (tmp != NULL)
584 		    limit_string(tmp);
585 		audit_krb5kdc_tgs_req_2ndtktmm(
586 			(struct in_addr *)from->address->contents,
587 			(in_port_t)from->port,
588 			0, cname, sname);
589 		krb5_klog_syslog(LOG_INFO,
590 				 "TGS_REQ %s: 2ND_TKT_MISMATCH: "
591 				 "authtime %d, %s for %s, 2nd tkt client %s",
592 				 fromstring, authtime,
593 				 cname ? cname : "<unknown client>",
594 				 sname ? sname : "<unknown server>",
595 				 tmp ? tmp : "<unknown>");
596 		errcode = KRB5KDC_ERR_SERVER_NOMATCH;
597 		goto cleanup;
598 	}
599 
600 	ticket_reply.enc_part.kvno = 0;
601 	ticket_reply.enc_part.enctype = t2enc->session->enctype;
602 	if ((errcode = krb5_encrypt_tkt_part(kdc_context, t2enc->session,
603 					     &ticket_reply))) {
604 	    status = "2ND_TKT_ENCRYPT";
605 	    goto cleanup;
606 	}
607 	st_idx++;
608     } else {
609 	/*
610 	 * Find the server key
611 	 */
612 	if ((errcode = krb5_dbe_find_enctype(kdc_context, &server,
613 					     -1, /* ignore keytype */
614 					     -1, /* Ignore salttype */
615 					     0,		/* Get highest kvno */
616 					     &server_key))) {
617 	    status = "FINDING_SERVER_KEY";
618 	    goto cleanup;
619 	}
620 	/* convert server.key into a real key (it may be encrypted
621 	 *        in the database) */
622 	if ((errcode = krb5_dbekd_decrypt_key_data(kdc_context,
623 						   &master_keyblock,
624 						   server_key, &encrypting_key,
625 						   NULL))) {
626 	    status = "DECRYPT_SERVER_KEY";
627 	    goto cleanup;
628 	}
629 	errcode = krb5_encrypt_tkt_part(kdc_context, &encrypting_key,
630 					&ticket_reply);
631 	krb5_free_keyblock_contents(kdc_context, &encrypting_key);
632 	if (errcode) {
633 	    status = "TKT_ENCRYPT";
634 	    goto cleanup;
635 	}
636 	ticket_reply.enc_part.kvno = server_key->key_data_kvno;
637     }
638 
639     /* Start assembling the response */
640     reply.msg_type = KRB5_TGS_REP;
641     reply.padata = 0;		/* always */
642     reply.client = header_ticket->enc_part2->client;
643     reply.enc_part.kvno = 0;		/* We are using the session key */
644     reply.ticket = &ticket_reply;
645 
646     reply_encpart.session = &session_key;
647     reply_encpart.nonce = request->nonce;
648 
649     /* copy the time fields EXCEPT for authtime; its location
650        is used for ktime */
651     reply_encpart.times = enc_tkt_reply.times;
652     reply_encpart.times.authtime = header_ticket->enc_part2->times.authtime;
653 
654     /* starttime is optional, and treated as authtime if not present.
655        so we can nuke it if it matches */
656     if (enc_tkt_reply.times.starttime == enc_tkt_reply.times.authtime)
657 	enc_tkt_reply.times.starttime = 0;
658 
659     nolrentry.lr_type = KRB5_LRQ_NONE;
660     nolrentry.value = 0;
661     nolrarray[0] = &nolrentry;
662     nolrarray[1] = 0;
663     reply_encpart.last_req = nolrarray;	/* not available for TGS reqs */
664     reply_encpart.key_exp = 0;		/* ditto */
665     reply_encpart.flags = enc_tkt_reply.flags;
666     reply_encpart.server = ticket_reply.server;
667 
668     /* use the session key in the ticket, unless there's a subsession key
669        in the AP_REQ */
670 
671     reply.enc_part.enctype = subkey ? subkey->enctype :
672 		    header_ticket->enc_part2->session->enctype;
673     errcode = krb5_encode_kdc_rep(kdc_context, KRB5_TGS_REP, &reply_encpart,
674 				  subkey ? 1 : 0,
675 				  subkey ? subkey :
676 				  header_ticket->enc_part2->session,
677 				  &reply, response);
678     if (errcode) {
679 	status = "ENCODE_KDC_REP";
680     } else {
681 	status = "ISSUE";
682     }
683 
684     if (ticket_reply.enc_part.ciphertext.data) {
685      memset(ticket_reply.enc_part.ciphertext.data, 0,
686 	   ticket_reply.enc_part.ciphertext.length);
687     free(ticket_reply.enc_part.ciphertext.data);
688 	ticket_reply.enc_part.ciphertext.data = NULL;
689     }
690     /* these parts are left on as a courtesy from krb5_encode_kdc_rep so we
691        can use them in raw form if needed.  But, we don't... */
692     if (reply.enc_part.ciphertext.data) {
693      memset(reply.enc_part.ciphertext.data, 0,
694 	   reply.enc_part.ciphertext.length);
695     free(reply.enc_part.ciphertext.data);
696 	reply.enc_part.ciphertext.data = NULL;
697     }
698 
699 cleanup:
700     if (status) {
701 	const char * emsg = NULL;
702 	    audit_krb5kdc_tgs_req((struct in_addr *)from->address->contents,
703 				(in_port_t)from->port, 0,
704 				cname ? cname : "<unknown client>",
705 				sname ? sname : "<unknown client>",
706 				errcode);
707 	if (!errcode)
708 	    rep_etypes2str(rep_etypestr, sizeof(rep_etypestr), &reply);
709 	if (errcode)
710 	    emsg = krb5_get_error_message (kdc_context, errcode);
711 	krb5_klog_syslog(LOG_INFO,
712 			 "TGS_REQ (%s) %s: %s: authtime %d, "
713 			 "%s%s %s for %s%s%s",
714 			 ktypestr,
715 			 fromstring, status, authtime,
716 			 !errcode ? rep_etypestr : "",
717 			 !errcode ? "," : "",
718 			 cname ? cname : "<unknown client>",
719 			 sname ? sname : "<unknown server>",
720 			 errcode ? ", " : "",
721 			 errcode ? emsg : "");
722 	if (errcode)
723 	    krb5_free_error_message (kdc_context, emsg);
724     }
725 
726     if (errcode) {
727         int got_err = 0;
728 	if (status == 0) {
729 	    status = krb5_get_error_message (kdc_context, errcode);
730 	    got_err = 1;
731 	}
732 	errcode -= ERROR_TABLE_BASE_krb5;
733 	if (errcode < 0 || errcode > 128)
734 	    errcode = KRB_ERR_GENERIC;
735 
736 	retval = prepare_error_tgs(request, header_ticket, errcode,
737 				   fromstring, response, status);
738 	if (got_err) {
739 	    krb5_free_error_message (kdc_context, status);
740 	    status = 0;
741 	}
742     }
743 
744     if (header_ticket)
745 	krb5_free_ticket(kdc_context, header_ticket);
746     if (request)
747 	krb5_free_kdc_req(kdc_context, request);
748     if (cname)
749 	free(cname);
750     if (sname)
751 	free(sname);
752     if (nprincs)
753 	krb5_db_free_principal(kdc_context, &server, 1);
754     if (session_key.contents)
755 	krb5_free_keyblock_contents(kdc_context, &session_key);
756     if (newtransited)
757 	free(enc_tkt_reply.transited.tr_contents.data);
758 
759     return retval;
760 }
761 
762 static krb5_error_code
763 prepare_error_tgs (krb5_kdc_req *request, krb5_ticket *ticket, int error,
764 		   const char *ident, krb5_data **response, const char *status)
765 {
766     krb5_error errpkt;
767     krb5_error_code retval;
768     krb5_data *scratch;
769 
770     errpkt.ctime = request->nonce;
771     errpkt.cusec = 0;
772 
773     if ((retval = krb5_us_timeofday(kdc_context, &errpkt.stime,
774 				    &errpkt.susec)))
775 	return(retval);
776     errpkt.error = error;
777     errpkt.server = request->server;
778     if (ticket && ticket->enc_part2)
779 	errpkt.client = ticket->enc_part2->client;
780     else
781 	errpkt.client = 0;
782     errpkt.text.length = strlen(status) + 1;
783     if (!(errpkt.text.data = malloc(errpkt.text.length)))
784 	return ENOMEM;
785     (void) strcpy(errpkt.text.data, status);
786 
787     if (!(scratch = (krb5_data *)malloc(sizeof(*scratch)))) {
788 	free(errpkt.text.data);
789 	return ENOMEM;
790     }
791     errpkt.e_data.length = 0;
792     errpkt.e_data.data = 0;
793 
794     retval = krb5_mk_error(kdc_context, &errpkt, scratch);
795     free(errpkt.text.data);
796     if (retval)
797 	free(scratch);
798     else
799 	*response = scratch;
800 
801     return retval;
802 }
803 
804 /*
805  * The request seems to be for a ticket-granting service somewhere else,
806  * but we don't have a ticket for the final TGS.  Try to give the requestor
807  * some intermediate realm.
808  */
809 static void
810 find_alternate_tgs(krb5_kdc_req *request, krb5_db_entry *server,
811 		   krb5_boolean *more, int *nprincs,
812 		   const krb5_fulladdr *from, char *cname)
813 {
814     krb5_error_code retval;
815     krb5_principal *plist, *pl2;
816     krb5_data tmp;
817 
818     *nprincs = 0;
819     *more = FALSE;
820 
821     /*
822      * Call to krb5_princ_component is normally not safe but is so
823      * here only because find_alternate_tgs() is only called from
824      * somewhere that has already checked the number of components in
825      * the principal.
826      */
827     if ((retval = krb5_walk_realm_tree(kdc_context,
828 		      krb5_princ_realm(kdc_context, request->server),
829 		      krb5_princ_component(kdc_context, request->server, 1),
830 				      &plist, KRB5_REALM_BRANCH_CHAR)))
831 	return;
832 
833     /* move to the end */
834     for (pl2 = plist; *pl2; pl2++);
835 
836     /* the first entry in this array is for krbtgt/local@local, so we
837        ignore it */
838     while (--pl2 > plist) {
839 	*nprincs = 1;
840 	tmp = *krb5_princ_realm(kdc_context, *pl2);
841 	krb5_princ_set_realm(kdc_context, *pl2,
842 			     krb5_princ_realm(kdc_context, tgs_server));
843 	retval = krb5_db_get_principal(kdc_context, *pl2, server, nprincs, more);
844 	krb5_princ_set_realm(kdc_context, *pl2, &tmp);
845 	if (retval) {
846 	    *nprincs = 0;
847 	    *more = FALSE;
848 	    krb5_free_realm_tree(kdc_context, plist);
849 	    return;
850 	}
851 	if (*more) {
852 	    krb5_db_free_principal(kdc_context, server, *nprincs);
853 	    continue;
854 	} else if (*nprincs == 1) {
855 	    /* Found it! */
856 	    krb5_principal tmpprinc;
857 	    char *sname;
858 
859 	    tmp = *krb5_princ_realm(kdc_context, *pl2);
860 	    krb5_princ_set_realm(kdc_context, *pl2,
861 				 krb5_princ_realm(kdc_context, tgs_server));
862 	    if ((retval = krb5_copy_principal(kdc_context, *pl2, &tmpprinc))) {
863 		krb5_db_free_principal(kdc_context, server, *nprincs);
864 		krb5_princ_set_realm(kdc_context, *pl2, &tmp);
865 		continue;
866 	    }
867 	    krb5_princ_set_realm(kdc_context, *pl2, &tmp);
868 
869 	    krb5_free_principal(kdc_context, request->server);
870 	    request->server = tmpprinc;
871 	    if (krb5_unparse_name(kdc_context, request->server, &sname)) {
872 
873 		audit_krb5kdc_tgs_req_alt_tgt(
874 			(struct in_addr *)from->address->contents,
875 			(in_port_t)from->port,
876 			0, cname, "<unparseable>", 0);
877 		krb5_klog_syslog(LOG_INFO,
878 		       "TGS_REQ: issuing alternate <un-unparseable> TGT");
879 	    } else {
880 		limit_string(sname);
881 		audit_krb5kdc_tgs_req_alt_tgt(
882 			(struct in_addr *)from->address->contents,
883 			(in_port_t)from->port,
884 			0, cname, sname, 0);
885 		krb5_klog_syslog(LOG_INFO,
886 		       "TGS_REQ: issuing TGT %s", sname);
887 		free(sname);
888 	    }
889 	    return;
890 	}
891 	krb5_db_free_principal(kdc_context, server, *nprincs);
892 	continue;
893     }
894 
895     *nprincs = 0;
896     *more = FALSE;
897     krb5_free_realm_tree(kdc_context, plist);
898     return;
899 }
900