xref: /titanic_44/usr/src/cmd/krb5/krb5kdc/do_tgs_req.c (revision 4a634bb80136cc001d14ab96addd9915105e5223)
1 /*
2  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 #pragma ident	"%Z%%M%	%I%	%E% SMI"
7 
8 /*
9  * kdc/do_tgs_req.c
10  *
11  * Copyright 1990,1991,2001 by the Massachusetts Institute of Technology.
12  * All Rights Reserved.
13  *
14  * Export of this software from the United States of America may
15  *   require a specific license from the United States Government.
16  *   It is the responsibility of any person or organization contemplating
17  *   export to obtain such a license before exporting.
18  *
19  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
20  * distribute this software and its documentation for any purpose and
21  * without fee is hereby granted, provided that the above copyright
22  * notice appear in all copies and that both that copyright notice and
23  * this permission notice appear in supporting documentation, and that
24  * the name of M.I.T. not be used in advertising or publicity pertaining
25  * to distribution of the software without specific, written prior
26  * permission.  Furthermore if you modify this software you must label
27  * your software as modified software and not distribute it in such a
28  * fashion that it might be confused with the original M.I.T. software.
29  * M.I.T. makes no representations about the suitability of
30  * this software for any purpose.  It is provided "as is" without express
31  * or implied warranty.
32  *
33  *
34  * KDC Routines to deal with TGS_REQ's
35  */
36 
37 #define NEED_SOCKETS
38 #include "k5-int.h"
39 #include "com_err.h"
40 
41 #include <syslog.h>
42 #ifdef HAVE_NETINET_IN_H
43 #include <sys/types.h>
44 #include <netinet/in.h>
45 #ifndef hpux
46 #include <arpa/inet.h>
47 #endif
48 #endif
49 
50 #include "kdc_util.h"
51 #include "policy.h"
52 #include "extern.h"
53 #include "adm_proto.h"
54 
55 extern krb5_error_code setup_server_realm(krb5_principal);
56 
57 static void find_alternate_tgs (krb5_kdc_req *, krb5_db_entry *,
58 				krb5_boolean *, int *,
59 		   		const krb5_fulladdr *from, char *cname);
60 
61 static krb5_error_code prepare_error_tgs (krb5_kdc_req *, krb5_ticket *,
62 					  int, const char *, krb5_data **,
63 					  const char *);
64 
65 /*ARGSUSED*/
66 krb5_error_code
67 process_tgs_req(krb5_data *pkt, const krb5_fulladdr *from,
68 		krb5_data **response)
69 {
70     krb5_keyblock * subkey;
71     krb5_kdc_req *request = 0;
72     krb5_db_entry server;
73     krb5_kdc_rep reply;
74     krb5_enc_kdc_rep_part reply_encpart;
75     krb5_ticket ticket_reply, *header_ticket = 0;
76     int st_idx = 0;
77     krb5_enc_tkt_part enc_tkt_reply;
78     krb5_transited enc_tkt_transited;
79     int newtransited = 0;
80     krb5_error_code retval = 0;
81     int nprincs = 0;
82     krb5_boolean more;
83     krb5_timestamp kdc_time, authtime=0;
84     krb5_keyblock session_key;
85     krb5_timestamp until, rtime;
86     krb5_keyblock encrypting_key;
87     krb5_key_data  *server_key;
88     char *cname = 0, *sname = 0, *tmp = 0;
89     const char *fromstring = 0;
90     krb5_last_req_entry *nolrarray[2], nolrentry;
91 /*    krb5_address *noaddrarray[1]; */
92     krb5_enctype useenctype;
93     int	errcode, errcode2;
94     register int i;
95     int firstpass = 1;
96     const char	*status = 0;
97     char ktypestr[128];
98     char rep_etypestr[128];
99     char fromstringbuf[70];
100     long long tmp_server_times, tmp_realm_times;
101 
102     (void) memset(&encrypting_key, 0, sizeof(krb5_keyblock));
103     (void) memset(&session_key, 0, sizeof(krb5_keyblock));
104 
105     retval = decode_krb5_tgs_req(pkt, &request);
106     if (retval)
107 	return retval;
108 
109     ktypes2str(ktypestr, sizeof(ktypestr),
110 	       request->nktypes, request->ktype);
111     /*
112      * setup_server_realm() sets up the global realm-specific data pointer.
113      */
114     if ((retval = setup_server_realm(request->server)))
115 	return retval;
116 
117     fromstring = inet_ntop(ADDRTYPE2FAMILY(from->address->addrtype),
118 			   from->address->contents,
119 			   fromstringbuf, sizeof(fromstringbuf));
120     if (!fromstring)
121 	fromstring = "<unknown>";
122 
123     if ((errcode = krb5_unparse_name(kdc_context, request->server, &sname))) {
124 	status = "UNPARSING SERVER";
125 	goto cleanup;
126     }
127     limit_string(sname);
128 
129    /* errcode = kdc_process_tgs_req(request, from, pkt, &req_authdat); */
130     errcode = kdc_process_tgs_req(request, from, pkt, &header_ticket, &subkey);
131 
132     if (header_ticket && header_ticket->enc_part2 &&
133 	(errcode2 = krb5_unparse_name(kdc_context,
134 				      header_ticket->enc_part2->client,
135 				      &cname))) {
136 	status = "UNPARSING CLIENT";
137 	errcode = errcode2;
138 	goto cleanup;
139     }
140     limit_string(cname);
141 
142     if (errcode) {
143 	status = "PROCESS_TGS";
144 	goto cleanup;
145     }
146 
147     if (!header_ticket) {
148 	errcode = KRB5_NO_TKT_SUPPLIED;	/* XXX? */
149 	status="UNEXPECTED NULL in header_ticket";
150 	goto cleanup;
151     }
152 
153     /*
154      * We've already dealt with the AP_REQ authentication, so we can
155      * use header_ticket freely.  The encrypted part (if any) has been
156      * decrypted with the session key.
157      */
158 
159     authtime = header_ticket->enc_part2->times.authtime;
160 
161     /* XXX make sure server here has the proper realm...taken from AP_REQ
162        header? */
163 
164     nprincs = 1;
165     if ((errcode = krb5_db_get_principal(kdc_context, request->server, &server,
166 					&nprincs, &more))) {
167 	status = "LOOKING_UP_SERVER";
168 	nprincs = 0;
169 	goto cleanup;
170     }
171 tgt_again:
172     if (more) {
173 	status = "NON_UNIQUE_PRINCIPAL";
174 	errcode = KRB5KDC_ERR_PRINCIPAL_NOT_UNIQUE;
175 	goto cleanup;
176     } else if (nprincs != 1) {
177 	/*
178 	 * might be a request for a TGT for some other realm; we
179 	 * should do our best to find such a TGS in this db
180 	 */
181 	if (firstpass && krb5_is_tgs_principal(request->server) == TRUE) {
182 	    if (krb5_princ_size(kdc_context, request->server) == 2) {
183 		krb5_data *server_1 =
184 		    krb5_princ_component(kdc_context, request->server, 1);
185 		krb5_data *tgs_1 =
186 		    krb5_princ_component(kdc_context, tgs_server, 1);
187 
188 		if (!tgs_1 || server_1->length != tgs_1->length ||
189 		    memcmp(server_1->data, tgs_1->data, tgs_1->length)) {
190 		    krb5_db_free_principal(kdc_context, &server, nprincs);
191 		    find_alternate_tgs(request, &server, &more, &nprincs,
192 				      from, cname);
193 		    firstpass = 0;
194 		    goto tgt_again;
195 		}
196 	    }
197 	}
198 	krb5_db_free_principal(kdc_context, &server, nprincs);
199 	status = "UNKNOWN_SERVER";
200 	errcode = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
201 	goto cleanup;
202     }
203 
204     if ((errcode = krb5_timeofday(kdc_context, &kdc_time))) {
205 	status = "TIME_OF_DAY";
206 	goto cleanup;
207     }
208 
209     if ((retval = validate_tgs_request(request, server, header_ticket,
210 				      kdc_time, &status))) {
211 	if (!status)
212 	    status = "UNKNOWN_REASON";
213 	errcode = retval + ERROR_TABLE_BASE_krb5;
214 	goto cleanup;
215     }
216 
217     /*
218      * We pick the session keytype here....
219      *
220      * Some special care needs to be taken in the user-to-user
221      * case, since we don't know what keytypes the application server
222      * which is doing user-to-user authentication can support.  We
223      * know that it at least must be able to support the encryption
224      * type of the session key in the TGT, since otherwise it won't be
225      * able to decrypt the U2U ticket!  So we use that in preference
226      * to anything else.
227      */
228     useenctype = 0;
229     if (isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) {
230 	krb5_keyblock *	st_sealing_key;
231 	krb5_kvno 	st_srv_kvno;
232 	krb5_enctype	etype;
233 
234 	/*
235 	 * Get the key for the second ticket, and decrypt it.
236 	 */
237 	if ((errcode = kdc_get_server_key(request->second_ticket[st_idx],
238 					 &st_sealing_key,
239 					 &st_srv_kvno))) {
240 	    status = "2ND_TKT_SERVER";
241 	    goto cleanup;
242 	}
243 	errcode = krb5_decrypt_tkt_part(kdc_context, st_sealing_key,
244 				       request->second_ticket[st_idx]);
245 	krb5_free_keyblock(kdc_context, st_sealing_key);
246 	if (errcode) {
247 	    status = "2ND_TKT_DECRYPT";
248 	    goto cleanup;
249 	}
250 
251 	etype = request->second_ticket[st_idx]->enc_part2->session->enctype;
252 	if (!krb5_c_valid_enctype(etype)) {
253 	    status = "BAD_ETYPE_IN_2ND_TKT";
254 	    errcode = KRB5KDC_ERR_ETYPE_NOSUPP;
255 	    goto cleanup;
256 	}
257 
258 	for (i = 0; i < request->nktypes; i++) {
259 	    if (request->ktype[i] == etype) {
260 		useenctype = etype;
261 		break;
262 	    }
263 	}
264     }
265 
266     /*
267      * Select the keytype for the ticket session key.
268      */
269     if ((useenctype == 0) &&
270 	(useenctype = select_session_keytype(kdc_context, &server,
271 					     request->nktypes,
272 					     request->ktype)) == 0) {
273 	/* unsupported ktype */
274 	status = "BAD_ENCRYPTION_TYPE";
275 	errcode = KRB5KDC_ERR_ETYPE_NOSUPP;
276 	goto cleanup;
277     }
278 
279     errcode = krb5_c_make_random_key(kdc_context, useenctype, &session_key);
280 
281     if (errcode) {
282 	/* random key failed */
283 	status = "RANDOM_KEY_FAILED";
284 	goto cleanup;
285     }
286 
287     ticket_reply.server = request->server; /* XXX careful for realm... */
288 
289     enc_tkt_reply.flags = 0;
290     enc_tkt_reply.times.starttime = 0;
291 
292     /*
293      * Fix header_ticket's starttime; if it's zero, fill in the
294      * authtime's value.
295      */
296     if (!(header_ticket->enc_part2->times.starttime))
297 	header_ticket->enc_part2->times.starttime =
298 	    header_ticket->enc_part2->times.authtime;
299 
300     /* don't use new addresses unless forwarded, see below */
301 
302     enc_tkt_reply.caddrs = header_ticket->enc_part2->caddrs;
303     /* noaddrarray[0] = 0; */
304     reply_encpart.caddrs = 0;		/* optional...don't put it in */
305 
306     /* It should be noted that local policy may affect the  */
307     /* processing of any of these flags.  For example, some */
308     /* realms may refuse to issue renewable tickets         */
309 
310     if (isflagset(request->kdc_options, KDC_OPT_FORWARDABLE))
311 	setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDABLE);
312 
313     if (isflagset(request->kdc_options, KDC_OPT_FORWARDED)) {
314 	setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDED);
315 
316 	/* include new addresses in ticket & reply */
317 
318 	enc_tkt_reply.caddrs = request->addresses;
319 	reply_encpart.caddrs = request->addresses;
320     }
321     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_FORWARDED))
322 	setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDED);
323 
324     if (isflagset(request->kdc_options, KDC_OPT_PROXIABLE))
325 	setflag(enc_tkt_reply.flags, TKT_FLG_PROXIABLE);
326 
327     if (isflagset(request->kdc_options, KDC_OPT_PROXY)) {
328 	setflag(enc_tkt_reply.flags, TKT_FLG_PROXY);
329 
330 	/* include new addresses in ticket & reply */
331 
332 	enc_tkt_reply.caddrs = request->addresses;
333 	reply_encpart.caddrs = request->addresses;
334     }
335 
336     if (isflagset(request->kdc_options, KDC_OPT_ALLOW_POSTDATE))
337 	setflag(enc_tkt_reply.flags, TKT_FLG_MAY_POSTDATE);
338 
339     if (isflagset(request->kdc_options, KDC_OPT_POSTDATED)) {
340 	setflag(enc_tkt_reply.flags, TKT_FLG_POSTDATED);
341 	setflag(enc_tkt_reply.flags, TKT_FLG_INVALID);
342 	enc_tkt_reply.times.starttime = request->from;
343     } else
344 	enc_tkt_reply.times.starttime = kdc_time;
345 
346     if (isflagset(request->kdc_options, KDC_OPT_VALIDATE)) {
347 	/* BEWARE of allocation hanging off of ticket & enc_part2, it belongs
348 	   to the caller */
349 	ticket_reply = *(header_ticket);
350 	enc_tkt_reply = *(header_ticket->enc_part2);
351 	clear(enc_tkt_reply.flags, TKT_FLG_INVALID);
352     }
353 
354     if (isflagset(request->kdc_options, KDC_OPT_RENEW)) {
355 	krb5_deltat old_life;
356 
357 	/* BEWARE of allocation hanging off of ticket & enc_part2, it belongs
358 	   to the caller */
359 	ticket_reply = *(header_ticket);
360 	enc_tkt_reply = *(header_ticket->enc_part2);
361 
362 	old_life = enc_tkt_reply.times.endtime - enc_tkt_reply.times.starttime;
363 
364 	enc_tkt_reply.times.starttime = kdc_time;
365 	enc_tkt_reply.times.endtime =
366 	    min(header_ticket->enc_part2->times.renew_till,
367 		kdc_time + old_life);
368     } else {
369 	/* not a renew request */
370 	enc_tkt_reply.times.starttime = kdc_time;
371 	until = (request->till == 0) ? kdc_infinity : request->till;
372 
373 	/* SUNW */
374         tmp_server_times = (long long) enc_tkt_reply.times.starttime
375 	  + server.max_life;
376 
377         tmp_realm_times = (long long) enc_tkt_reply.times.starttime
378 	  + max_life_for_realm;
379 
380         enc_tkt_reply.times.endtime =
381   	  min(until,
382 	    min(tmp_server_times,
383 		min(tmp_realm_times,
384 			min(header_ticket->enc_part2->times.endtime,
385 			    KRB5_KDB_EXPIRATION)))); /* SUNW */
386 /*
387 	enc_tkt_reply.times.endtime =
388 	    min(until, min(enc_tkt_reply.times.starttime + server.max_life,
389 			   min(enc_tkt_reply.times.starttime + max_life_for_realm,
390 			       min(header_ticket->enc_part2->times.endtime)));
391 */
392 	if (isflagset(request->kdc_options, KDC_OPT_RENEWABLE_OK) &&
393 	    (enc_tkt_reply.times.endtime < request->till) &&
394 	    isflagset(header_ticket->enc_part2->flags,
395 		  TKT_FLG_RENEWABLE)) {
396 	    setflag(request->kdc_options, KDC_OPT_RENEWABLE);
397 	    request->rtime =
398 		min(request->till,
399 		    min(KRB5_KDB_EXPIRATION,
400 		    header_ticket->enc_part2->times.renew_till));
401 	}
402     }
403     rtime = (request->rtime == 0) ? kdc_infinity : request->rtime;
404 
405     if (isflagset(request->kdc_options, KDC_OPT_RENEWABLE)) {
406 	/* already checked above in policy check to reject request for a
407 	   renewable ticket using a non-renewable ticket */
408 	setflag(enc_tkt_reply.flags, TKT_FLG_RENEWABLE);
409 	tmp_realm_times =  (long long) enc_tkt_reply.times.starttime +
410 		min(server.max_renewable_life,max_renewable_life_for_realm);
411 	enc_tkt_reply.times.renew_till =
412 	    min(rtime,
413 		min(header_ticket->enc_part2->times.renew_till,
414 				min (tmp_realm_times, KRB5_KDB_EXPIRATION)));
415     } else {
416 	enc_tkt_reply.times.renew_till = 0;
417     }
418 
419     /*
420      * Set authtime to be the same as header_ticket's
421      */
422     enc_tkt_reply.times.authtime = header_ticket->enc_part2->times.authtime;
423 
424     /*
425      * Propagate the preauthentication flags through to the returned ticket.
426      */
427     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_PRE_AUTH))
428 	setflag(enc_tkt_reply.flags, TKT_FLG_PRE_AUTH);
429 
430     if (isflagset(header_ticket->enc_part2->flags, TKT_FLG_HW_AUTH))
431 	setflag(enc_tkt_reply.flags, TKT_FLG_HW_AUTH);
432 
433     /* starttime is optional, and treated as authtime if not present.
434        so we can nuke it if it matches */
435     if (enc_tkt_reply.times.starttime == enc_tkt_reply.times.authtime)
436 	enc_tkt_reply.times.starttime = 0;
437 
438     /* assemble any authorization data */
439     if (request->authorization_data.ciphertext.data) {
440 	krb5_data scratch;
441 
442 	scratch.length = request->authorization_data.ciphertext.length;
443 	if (!(scratch.data =
444 	      malloc(request->authorization_data.ciphertext.length))) {
445 	    status = "AUTH_NOMEM";
446 	    errcode = ENOMEM;
447 	    goto cleanup;
448 	}
449 
450 	if ((errcode = krb5_c_decrypt(kdc_context,
451 				      header_ticket->enc_part2->session,
452 				      KRB5_KEYUSAGE_TGS_REQ_AD_SESSKEY,
453 				      0, &request->authorization_data,
454 				      &scratch))) {
455 	    status = "AUTH_ENCRYPT_FAIL";
456 	    free(scratch.data);
457 	    goto cleanup;
458 	}
459 
460 	/* scratch now has the authorization data, so we decode it */
461 	errcode = decode_krb5_authdata(&scratch, &(request->unenc_authdata));
462 	free(scratch.data);
463 	if (errcode) {
464 	    status = "AUTH_DECODE";
465 	    goto cleanup;
466 	}
467 
468 	if ((errcode =
469 	     concat_authorization_data(request->unenc_authdata,
470 				       header_ticket->enc_part2->authorization_data,
471 				       &enc_tkt_reply.authorization_data))) {
472 	    status = "CONCAT_AUTH";
473 	    goto cleanup;
474 	}
475     } else
476 	enc_tkt_reply.authorization_data =
477 	    header_ticket->enc_part2->authorization_data;
478 
479     enc_tkt_reply.session = &session_key;
480     enc_tkt_reply.client = header_ticket->enc_part2->client;
481     enc_tkt_reply.transited.tr_type = KRB5_DOMAIN_X500_COMPRESS;
482     enc_tkt_reply.transited.tr_contents = empty_string; /* equivalent of "" */
483 
484     /*
485      * Only add the realm of the presented tgt to the transited list if
486      * it is different than the local realm (cross-realm) and it is different
487      * than the realm of the client (since the realm of the client is already
488      * implicitly part of the transited list and should not be explicitly
489      * listed).
490      */
491 
492     /* realm compare is like strcmp, but knows how to deal with these args */
493     if (realm_compare(header_ticket->server, tgs_server) ||
494 	realm_compare(header_ticket->server, enc_tkt_reply.client)) {
495 	/* tgt issued by local realm or issued by realm of client */
496 	enc_tkt_reply.transited = header_ticket->enc_part2->transited;
497     } else {
498 	/* tgt issued by some other realm and not the realm of the client */
499 	/* assemble new transited field into allocated storage */
500 	if (header_ticket->enc_part2->transited.tr_type !=
501 	    KRB5_DOMAIN_X500_COMPRESS) {
502 	    status = "BAD_TRTYPE";
503 	    errcode = KRB5KDC_ERR_TRTYPE_NOSUPP;
504 	    goto cleanup;
505 	}
506 	enc_tkt_transited.tr_type = KRB5_DOMAIN_X500_COMPRESS;
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 	    krb5_klog_syslog (LOG_ERR,
546 			      "unexpected error checking transit from "
547 			      "'%s' to '%s' via '%.*s%s': %s",
548 			      cname ? cname : "<unknown client>",
549 			      sname ? sname : "<unknown server>",
550 			      tlen,
551 			      enc_tkt_reply.transited.tr_contents.data,
552 			      tdots, error_message (errcode));
553     } else
554 	krb5_klog_syslog (LOG_INFO, "not checking transit path");
555     if (reject_bad_transit
556 	&& !isflagset (enc_tkt_reply.flags, TKT_FLG_TRANSIT_POLICY_CHECKED)) {
557 	errcode = KRB5KDC_ERR_POLICY;
558 	status = "BAD_TRANSIT";
559 	goto cleanup;
560     }
561 
562     ticket_reply.enc_part2 = &enc_tkt_reply;
563 
564     /*
565      * If we are doing user-to-user authentication, then make sure
566      * that the client for the second ticket matches the request
567      * server, and then encrypt the ticket using the session key of
568      * the second ticket.
569      */
570     if (isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) {
571 	/*
572 	 * Make sure the client for the second ticket matches
573 	 * requested server.
574 	 */
575 	krb5_enc_tkt_part *t2enc = request->second_ticket[st_idx]->enc_part2;
576 	krb5_principal client2 = t2enc->client;
577 	if (!krb5_principal_compare(kdc_context, request->server, client2)) {
578 		if ((errcode = krb5_unparse_name(kdc_context, client2, &tmp)))
579 			tmp = 0;
580 		if (tmp != NULL)
581 			limit_string(tmp);
582 		audit_krb5kdc_tgs_req_2ndtktmm(
583 			(struct in_addr *)from->address->contents,
584 			(in_port_t)from->port,
585 			0, cname, sname);
586 		krb5_klog_syslog(LOG_INFO,
587 				 "TGS_REQ %s: 2ND_TKT_MISMATCH: "
588 				 "authtime %d, %s for %s, 2nd tkt client %s",
589 				 fromstring, authtime,
590 				 cname ? cname : "<unknown client>",
591 				 sname ? sname : "<unknown server>",
592 				 tmp ? tmp : "<unknown>");
593 		errcode = KRB5KDC_ERR_SERVER_NOMATCH;
594 		goto cleanup;
595 	}
596 
597 	ticket_reply.enc_part.kvno = 0;
598 	ticket_reply.enc_part.enctype = t2enc->session->enctype;
599 	if ((errcode = krb5_encrypt_tkt_part(kdc_context, t2enc->session,
600 					     &ticket_reply))) {
601 	    status = "2ND_TKT_ENCRYPT";
602 	    goto cleanup;
603 	}
604 	st_idx++;
605     } else {
606 	/*
607 	 * Find the server key
608 	 */
609 	if ((errcode = krb5_dbe_find_enctype(kdc_context, &server,
610 					     -1, /* ignore keytype */
611 					     -1, /* Ignore salttype */
612 					     0,		/* Get highest kvno */
613 					     &server_key))) {
614 	    status = "FINDING_SERVER_KEY";
615 	    goto cleanup;
616 	}
617 	/* convert server.key into a real key (it may be encrypted
618 	 *        in the database) */
619 	if ((errcode = krb5_dbekd_decrypt_key_data(kdc_context,
620 						   &master_keyblock,
621 						   server_key, &encrypting_key,
622 						   NULL))) {
623 	    status = "DECRYPT_SERVER_KEY";
624 	    goto cleanup;
625 	}
626 	errcode = krb5_encrypt_tkt_part(kdc_context, &encrypting_key,
627 					&ticket_reply);
628 	krb5_free_keyblock_contents(kdc_context, &encrypting_key);
629 	if (errcode) {
630 	    status = "TKT_ENCRYPT";
631 	    goto cleanup;
632 	}
633 	ticket_reply.enc_part.kvno = server_key->key_data_kvno;
634     }
635 
636     /* Start assembling the response */
637     reply.msg_type = KRB5_TGS_REP;
638     reply.padata = 0;		/* always */
639     reply.client = header_ticket->enc_part2->client;
640     reply.enc_part.kvno = 0;		/* We are using the session key */
641     reply.ticket = &ticket_reply;
642 
643     reply_encpart.session = &session_key;
644     reply_encpart.nonce = request->nonce;
645 
646     /* copy the time fields EXCEPT for authtime; its location
647        is used for ktime */
648     reply_encpart.times = enc_tkt_reply.times;
649     reply_encpart.times.authtime = header_ticket->enc_part2->times.authtime;
650 
651     /* starttime is optional, and treated as authtime if not present.
652        so we can nuke it if it matches */
653     if (enc_tkt_reply.times.starttime == enc_tkt_reply.times.authtime)
654 	enc_tkt_reply.times.starttime = 0;
655 
656     nolrentry.lr_type = KRB5_LRQ_NONE;
657     nolrentry.value = 0;
658     nolrarray[0] = &nolrentry;
659     nolrarray[1] = 0;
660     reply_encpart.last_req = nolrarray;	/* not available for TGS reqs */
661     reply_encpart.key_exp = 0;		/* ditto */
662     reply_encpart.flags = enc_tkt_reply.flags;
663     reply_encpart.server = ticket_reply.server;
664 
665     /* use the session key in the ticket, unless there's a subsession key
666        in the AP_REQ */
667 
668     reply.enc_part.enctype = subkey ? subkey->enctype :
669 		    header_ticket->enc_part2->session->enctype;
670     errcode = krb5_encode_kdc_rep(kdc_context, KRB5_TGS_REP, &reply_encpart,
671 				  subkey ? 1 : 0,
672 				  subkey ? subkey :
673 				  header_ticket->enc_part2->session,
674 				  &reply, response);
675     if (errcode) {
676 	status = "ENCODE_KDC_REP";
677     } else {
678 	status = "ISSUE";
679     }
680 
681     if (ticket_reply.enc_part.ciphertext.data) {
682      memset(ticket_reply.enc_part.ciphertext.data, 0,
683 	   ticket_reply.enc_part.ciphertext.length);
684     free(ticket_reply.enc_part.ciphertext.data);
685 	ticket_reply.enc_part.ciphertext.data = NULL;
686     }
687     /* these parts are left on as a courtesy from krb5_encode_kdc_rep so we
688        can use them in raw form if needed.  But, we don't... */
689     if (reply.enc_part.ciphertext.data) {
690      memset(reply.enc_part.ciphertext.data, 0,
691 	   reply.enc_part.ciphertext.length);
692     free(reply.enc_part.ciphertext.data);
693 	reply.enc_part.ciphertext.data = NULL;
694     }
695 
696 cleanup:
697     if (status) {
698 	    audit_krb5kdc_tgs_req((struct in_addr *)from->address->contents,
699 				(in_port_t)from->port, 0,
700 				cname ? cname : "<unknown client>",
701 				sname ? sname : "<unknown client>",
702 				errcode);
703 	if (!errcode)
704 	    rep_etypes2str(rep_etypestr, sizeof(rep_etypestr), &reply);
705         krb5_klog_syslog(LOG_INFO,
706 			 "TGS_REQ (%s) %s: %s: authtime %d, "
707 			 "%s%s %s for %s%s%s",
708 			 ktypestr,
709 			 fromstring, status, authtime,
710 			 !errcode ? rep_etypestr : "",
711 			 !errcode ? "," : "",
712 			 cname ? cname : "<unknown client>",
713 			 sname ? sname : "<unknown server>",
714 			 errcode ? ", " : "",
715 			 errcode ? error_message(errcode) : "");
716     }
717 
718     if (errcode) {
719 	if (status == 0)
720 	    status = error_message (errcode);
721 	errcode -= ERROR_TABLE_BASE_krb5;
722 	if (errcode < 0 || errcode > 128)
723 	    errcode = KRB_ERR_GENERIC;
724 
725 	retval = prepare_error_tgs(request, header_ticket, errcode,
726 				   fromstring, response, status);
727     }
728 
729     if (header_ticket)
730 	krb5_free_ticket(kdc_context, header_ticket);
731     if (request)
732 	krb5_free_kdc_req(kdc_context, request);
733     if (cname)
734 	free(cname);
735     if (sname)
736 	free(sname);
737     if (nprincs)
738 	krb5_db_free_principal(kdc_context, &server, 1);
739     if (session_key.contents)
740 	krb5_free_keyblock_contents(kdc_context, &session_key);
741     if (newtransited)
742 	free(enc_tkt_reply.transited.tr_contents.data);
743 
744     return retval;
745 }
746 
747 static krb5_error_code
748 prepare_error_tgs (krb5_kdc_req *request, krb5_ticket *ticket, int error,
749 		   const char *ident, krb5_data **response, const char *status)
750 {
751     krb5_error errpkt;
752     krb5_error_code retval;
753     krb5_data *scratch;
754 
755     errpkt.ctime = request->nonce;
756     errpkt.cusec = 0;
757 
758     if ((retval = krb5_us_timeofday(kdc_context, &errpkt.stime,
759 				    &errpkt.susec)))
760 	return(retval);
761     errpkt.error = error;
762     errpkt.server = request->server;
763     if (ticket && ticket->enc_part2)
764 	errpkt.client = ticket->enc_part2->client;
765     else
766 	errpkt.client = 0;
767     errpkt.text.length = strlen(status) + 1;
768     if (!(errpkt.text.data = malloc(errpkt.text.length)))
769 	return ENOMEM;
770     (void) strcpy(errpkt.text.data, status);
771 
772     if (!(scratch = (krb5_data *)malloc(sizeof(*scratch)))) {
773 	free(errpkt.text.data);
774 	return ENOMEM;
775     }
776     errpkt.e_data.length = 0;
777     errpkt.e_data.data = 0;
778 
779     retval = krb5_mk_error(kdc_context, &errpkt, scratch);
780     free(errpkt.text.data);
781     if (retval)
782 	free(scratch);
783     else
784 	*response = scratch;
785 
786     return retval;
787 }
788 
789 /*
790  * The request seems to be for a ticket-granting service somewhere else,
791  * but we don't have a ticket for the final TGS.  Try to give the requestor
792  * some intermediate realm.
793  */
794 static void
795 find_alternate_tgs(krb5_kdc_req *request, krb5_db_entry *server,
796 		   krb5_boolean *more, int *nprincs,
797 		   const krb5_fulladdr *from, char *cname)
798 {
799     krb5_error_code retval;
800     krb5_principal *plist, *pl2;
801     krb5_data tmp;
802 
803     *nprincs = 0;
804     *more = FALSE;
805 
806     /*
807      * Call to krb5_princ_component is normally not safe but is so
808      * here only because find_alternate_tgs() is only called from
809      * somewhere that has already checked the number of components in
810      * the principal.
811      */
812     if ((retval = krb5_walk_realm_tree(kdc_context,
813 		      krb5_princ_realm(kdc_context, request->server),
814 		      krb5_princ_component(kdc_context, request->server, 1),
815 				      &plist, KRB5_REALM_BRANCH_CHAR)))
816 	return;
817 
818     /* move to the end */
819     for (pl2 = plist; *pl2; pl2++);
820 
821     /* the first entry in this array is for krbtgt/local@local, so we
822        ignore it */
823     while (--pl2 > plist) {
824 	*nprincs = 1;
825 	tmp = *krb5_princ_realm(kdc_context, *pl2);
826 	krb5_princ_set_realm(kdc_context, *pl2,
827 			     krb5_princ_realm(kdc_context, tgs_server));
828 	retval = krb5_db_get_principal(kdc_context, *pl2, server, nprincs, more);
829 	krb5_princ_set_realm(kdc_context, *pl2, &tmp);
830 	if (retval) {
831 	    *nprincs = 0;
832 	    *more = FALSE;
833 	    krb5_free_realm_tree(kdc_context, plist);
834 	    return;
835 	}
836 	if (*more) {
837 	    krb5_db_free_principal(kdc_context, server, *nprincs);
838 	    continue;
839 	} else if (*nprincs == 1) {
840 	    /* Found it! */
841 	    krb5_principal tmpprinc;
842 	    char *sname;
843 
844 	    tmp = *krb5_princ_realm(kdc_context, *pl2);
845 	    krb5_princ_set_realm(kdc_context, *pl2,
846 				 krb5_princ_realm(kdc_context, tgs_server));
847 	    if ((retval = krb5_copy_principal(kdc_context, *pl2, &tmpprinc))) {
848 		krb5_db_free_principal(kdc_context, server, *nprincs);
849 		krb5_princ_set_realm(kdc_context, *pl2, &tmp);
850 		continue;
851 	    }
852 	    krb5_princ_set_realm(kdc_context, *pl2, &tmp);
853 
854 	    krb5_free_principal(kdc_context, request->server);
855 	    request->server = tmpprinc;
856 	    if (krb5_unparse_name(kdc_context, request->server, &sname)) {
857 
858 		audit_krb5kdc_tgs_req_alt_tgt(
859 			(struct in_addr *)from->address->contents,
860 			(in_port_t)from->port,
861 			0, cname, "<unparseable>", 0);
862 		krb5_klog_syslog(LOG_INFO,
863 		       "TGS_REQ: issuing alternate <un-unparseable> TGT");
864 	    } else {
865 		limit_string(sname);
866 		audit_krb5kdc_tgs_req_alt_tgt(
867 			(struct in_addr *)from->address->contents,
868 			(in_port_t)from->port,
869 			0, cname, sname, 0);
870 		krb5_klog_syslog(LOG_INFO,
871 		       "TGS_REQ: issuing TGT %s", sname);
872 		free(sname);
873 	    }
874 	    return;
875 	}
876 	krb5_db_free_principal(kdc_context, server, *nprincs);
877 	continue;
878     }
879 
880     *nprincs = 0;
881     *more = FALSE;
882     krb5_free_realm_tree(kdc_context, plist);
883     return;
884 }
885