1 /* $NetBSD: rd_req.c,v 1.3 2023/06/19 21:41:44 christos Exp $ */
2
3
4 /*
5 * Copyright (c) 1997 - 2007 Kungliga Tekniska Högskolan
6 * (Royal Institute of Technology, Stockholm, Sweden).
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * 3. Neither the name of the Institute nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #include "krb5_locl.h"
38
39 static krb5_error_code
decrypt_tkt_enc_part(krb5_context context,krb5_keyblock * key,EncryptedData * enc_part,EncTicketPart * decr_part)40 decrypt_tkt_enc_part (krb5_context context,
41 krb5_keyblock *key,
42 EncryptedData *enc_part,
43 EncTicketPart *decr_part)
44 {
45 krb5_error_code ret;
46 krb5_data plain;
47 size_t len;
48 krb5_crypto crypto;
49
50 ret = krb5_crypto_init(context, key, 0, &crypto);
51 if (ret)
52 return ret;
53 ret = krb5_decrypt_EncryptedData (context,
54 crypto,
55 KRB5_KU_TICKET,
56 enc_part,
57 &plain);
58 krb5_crypto_destroy(context, crypto);
59 if (ret)
60 return ret;
61
62 ret = decode_EncTicketPart(plain.data, plain.length, decr_part, &len);
63 if (ret)
64 krb5_set_error_message(context, ret,
65 N_("Failed to decode encrypted "
66 "ticket part", ""));
67 krb5_data_free (&plain);
68 return ret;
69 }
70
71 static krb5_error_code
decrypt_authenticator(krb5_context context,EncryptionKey * key,EncryptedData * enc_part,Authenticator * authenticator,krb5_key_usage usage)72 decrypt_authenticator (krb5_context context,
73 EncryptionKey *key,
74 EncryptedData *enc_part,
75 Authenticator *authenticator,
76 krb5_key_usage usage)
77 {
78 krb5_error_code ret;
79 krb5_data plain;
80 size_t len;
81 krb5_crypto crypto;
82
83 ret = krb5_crypto_init(context, key, 0, &crypto);
84 if (ret)
85 return ret;
86 ret = krb5_decrypt_EncryptedData (context,
87 crypto,
88 usage /* KRB5_KU_AP_REQ_AUTH */,
89 enc_part,
90 &plain);
91 /* for backwards compatibility, also try the old usage */
92 if (ret && usage == KRB5_KU_TGS_REQ_AUTH)
93 ret = krb5_decrypt_EncryptedData (context,
94 crypto,
95 KRB5_KU_AP_REQ_AUTH,
96 enc_part,
97 &plain);
98 krb5_crypto_destroy(context, crypto);
99 if (ret)
100 return ret;
101
102 ret = decode_Authenticator(plain.data, plain.length,
103 authenticator, &len);
104 krb5_data_free (&plain);
105 return ret;
106 }
107
108 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_decode_ap_req(krb5_context context,const krb5_data * inbuf,krb5_ap_req * ap_req)109 krb5_decode_ap_req(krb5_context context,
110 const krb5_data *inbuf,
111 krb5_ap_req *ap_req)
112 {
113 krb5_error_code ret;
114 size_t len;
115 ret = decode_AP_REQ(inbuf->data, inbuf->length, ap_req, &len);
116 if (ret)
117 return ret;
118 if (ap_req->pvno != 5){
119 free_AP_REQ(ap_req);
120 krb5_clear_error_message (context);
121 return KRB5KRB_AP_ERR_BADVERSION;
122 }
123 if (ap_req->msg_type != krb_ap_req){
124 free_AP_REQ(ap_req);
125 krb5_clear_error_message (context);
126 return KRB5KRB_AP_ERR_MSG_TYPE;
127 }
128 if (ap_req->ticket.tkt_vno != 5){
129 free_AP_REQ(ap_req);
130 krb5_clear_error_message (context);
131 return KRB5KRB_AP_ERR_BADVERSION;
132 }
133 return 0;
134 }
135
136 static krb5_error_code
check_transited(krb5_context context,Ticket * ticket,EncTicketPart * enc)137 check_transited(krb5_context context, Ticket *ticket, EncTicketPart *enc)
138 {
139 char **realms;
140 unsigned int num_realms, n;
141 krb5_error_code ret;
142
143 /*
144 * Windows 2000 and 2003 uses this inside their TGT so it's normaly
145 * not seen by others, however, samba4 joined with a Windows AD as
146 * a Domain Controller gets exposed to this.
147 */
148 if(enc->transited.tr_type == 0 && enc->transited.contents.length == 0)
149 return 0;
150
151 if(enc->transited.tr_type != DOMAIN_X500_COMPRESS)
152 return KRB5KDC_ERR_TRTYPE_NOSUPP;
153
154 if(enc->transited.contents.length == 0)
155 return 0;
156
157 ret = krb5_domain_x500_decode(context, enc->transited.contents,
158 &realms, &num_realms,
159 enc->crealm,
160 ticket->realm);
161 if(ret)
162 return ret;
163 ret = krb5_check_transited(context, enc->crealm,
164 ticket->realm,
165 realms, num_realms, NULL);
166 for (n = 0; n < num_realms; n++)
167 free(realms[n]);
168 free(realms);
169 return ret;
170 }
171
172 static krb5_error_code
find_etypelist(krb5_context context,krb5_auth_context auth_context,EtypeList * etypes)173 find_etypelist(krb5_context context,
174 krb5_auth_context auth_context,
175 EtypeList *etypes)
176 {
177 krb5_error_code ret;
178 krb5_data data;
179
180 ret = _krb5_get_ad(context, auth_context->authenticator->authorization_data, NULL, KRB5_AUTHDATA_GSS_API_ETYPE_NEGOTIATION, &data);
181 if (ret)
182 return 0;
183
184 ret = decode_EtypeList(data.data, data.length, etypes, NULL);
185 krb5_data_free(&data);
186 if (ret)
187 krb5_clear_error_message(context);
188
189 return ret;
190 }
191
192 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_decrypt_ticket(krb5_context context,Ticket * ticket,krb5_keyblock * key,EncTicketPart * out,krb5_flags flags)193 krb5_decrypt_ticket(krb5_context context,
194 Ticket *ticket,
195 krb5_keyblock *key,
196 EncTicketPart *out,
197 krb5_flags flags)
198 {
199 EncTicketPart t;
200 krb5_error_code ret;
201 ret = decrypt_tkt_enc_part (context, key, &ticket->enc_part, &t);
202 if (ret)
203 return ret;
204
205 {
206 krb5_timestamp now;
207 time_t start = t.authtime;
208
209 krb5_timeofday (context, &now);
210 if(t.starttime)
211 start = *t.starttime;
212 if(start - now > context->max_skew
213 || (t.flags.invalid
214 && !(flags & KRB5_VERIFY_AP_REQ_IGNORE_INVALID))) {
215 free_EncTicketPart(&t);
216 krb5_clear_error_message (context);
217 return KRB5KRB_AP_ERR_TKT_NYV;
218 }
219 if(now - t.endtime > context->max_skew) {
220 free_EncTicketPart(&t);
221 krb5_clear_error_message (context);
222 return KRB5KRB_AP_ERR_TKT_EXPIRED;
223 }
224
225 if(!t.flags.transited_policy_checked) {
226 ret = check_transited(context, ticket, &t);
227 if(ret) {
228 free_EncTicketPart(&t);
229 return ret;
230 }
231 }
232 }
233
234 if(out)
235 *out = t;
236 else
237 free_EncTicketPart(&t);
238 return 0;
239 }
240
241 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_verify_authenticator_checksum(krb5_context context,krb5_auth_context ac,void * data,size_t len)242 krb5_verify_authenticator_checksum(krb5_context context,
243 krb5_auth_context ac,
244 void *data,
245 size_t len)
246 {
247 krb5_error_code ret;
248 krb5_keyblock *key = NULL;
249 krb5_authenticator authenticator;
250 krb5_crypto crypto;
251
252 ret = krb5_auth_con_getauthenticator(context, ac, &authenticator);
253 if (ret)
254 return ret;
255 if (authenticator->cksum == NULL) {
256 ret = -17;
257 goto out;
258 }
259 ret = krb5_auth_con_getkey(context, ac, &key);
260 if (ret)
261 goto out;
262 ret = krb5_crypto_init(context, key, 0, &crypto);
263 if (ret)
264 goto out;
265 ret = krb5_verify_checksum(context, crypto,
266 KRB5_KU_AP_REQ_AUTH_CKSUM,
267 data, len, authenticator->cksum);
268 krb5_crypto_destroy(context, crypto);
269 out:
270 krb5_free_authenticator(context, &authenticator);
271 krb5_free_keyblock(context, key);
272 return ret;
273 }
274
275
276 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_verify_ap_req(krb5_context context,krb5_auth_context * auth_context,krb5_ap_req * ap_req,krb5_const_principal server,krb5_keyblock * keyblock,krb5_flags flags,krb5_flags * ap_req_options,krb5_ticket ** ticket)277 krb5_verify_ap_req(krb5_context context,
278 krb5_auth_context *auth_context,
279 krb5_ap_req *ap_req,
280 krb5_const_principal server,
281 krb5_keyblock *keyblock,
282 krb5_flags flags,
283 krb5_flags *ap_req_options,
284 krb5_ticket **ticket)
285 {
286 return krb5_verify_ap_req2 (context,
287 auth_context,
288 ap_req,
289 server,
290 keyblock,
291 flags,
292 ap_req_options,
293 ticket,
294 KRB5_KU_AP_REQ_AUTH);
295 }
296
297 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_verify_ap_req2(krb5_context context,krb5_auth_context * auth_context,krb5_ap_req * ap_req,krb5_const_principal server,krb5_keyblock * keyblock,krb5_flags flags,krb5_flags * ap_req_options,krb5_ticket ** ticket,krb5_key_usage usage)298 krb5_verify_ap_req2(krb5_context context,
299 krb5_auth_context *auth_context,
300 krb5_ap_req *ap_req,
301 krb5_const_principal server,
302 krb5_keyblock *keyblock,
303 krb5_flags flags,
304 krb5_flags *ap_req_options,
305 krb5_ticket **ticket,
306 krb5_key_usage usage)
307 {
308 krb5_ticket *t;
309 krb5_auth_context ac;
310 krb5_error_code ret;
311 EtypeList etypes;
312
313 memset(&etypes, 0, sizeof(etypes));
314
315 if (ticket)
316 *ticket = NULL;
317
318 if (auth_context && *auth_context) {
319 ac = *auth_context;
320 } else {
321 ret = krb5_auth_con_init (context, &ac);
322 if (ret)
323 return ret;
324 }
325
326 t = calloc(1, sizeof(*t));
327 if (t == NULL) {
328 ret = krb5_enomem(context);
329 goto out;
330 }
331
332 if (ap_req->ap_options.use_session_key && ac->keyblock){
333 ret = krb5_decrypt_ticket(context, &ap_req->ticket,
334 ac->keyblock,
335 &t->ticket,
336 flags);
337 krb5_free_keyblock(context, ac->keyblock);
338 ac->keyblock = NULL;
339 }else
340 ret = krb5_decrypt_ticket(context, &ap_req->ticket,
341 keyblock,
342 &t->ticket,
343 flags);
344
345 if(ret)
346 goto out;
347
348 ret = _krb5_principalname2krb5_principal(context,
349 &t->server,
350 ap_req->ticket.sname,
351 ap_req->ticket.realm);
352 if (ret) goto out;
353 ret = _krb5_principalname2krb5_principal(context,
354 &t->client,
355 t->ticket.cname,
356 t->ticket.crealm);
357 if (ret) goto out;
358
359 ret = decrypt_authenticator (context,
360 &t->ticket.key,
361 &ap_req->authenticator,
362 ac->authenticator,
363 usage);
364 if (ret)
365 goto out;
366
367 {
368 krb5_principal p1, p2;
369 krb5_boolean res;
370
371 _krb5_principalname2krb5_principal(context,
372 &p1,
373 ac->authenticator->cname,
374 ac->authenticator->crealm);
375 _krb5_principalname2krb5_principal(context,
376 &p2,
377 t->ticket.cname,
378 t->ticket.crealm);
379 res = krb5_principal_compare (context, p1, p2);
380 krb5_free_principal (context, p1);
381 krb5_free_principal (context, p2);
382 if (!res) {
383 ret = KRB5KRB_AP_ERR_BADMATCH;
384 krb5_clear_error_message (context);
385 goto out;
386 }
387 }
388
389 /* check addresses */
390
391 if (t->ticket.caddr
392 && ac->remote_address
393 && !krb5_address_search (context,
394 ac->remote_address,
395 t->ticket.caddr)) {
396 ret = KRB5KRB_AP_ERR_BADADDR;
397 krb5_clear_error_message (context);
398 goto out;
399 }
400
401 /* check timestamp in authenticator */
402 {
403 krb5_timestamp now;
404
405 krb5_timeofday (context, &now);
406
407 if (labs(ac->authenticator->ctime - now) > context->max_skew) {
408 ret = KRB5KRB_AP_ERR_SKEW;
409 krb5_clear_error_message (context);
410 goto out;
411 }
412 }
413
414 if (ac->authenticator->seq_number)
415 krb5_auth_con_setremoteseqnumber(context, ac,
416 *ac->authenticator->seq_number);
417
418 /* XXX - Xor sequence numbers */
419
420 if (ac->authenticator->subkey) {
421 ret = krb5_auth_con_setremotesubkey(context, ac,
422 ac->authenticator->subkey);
423 if (ret)
424 goto out;
425 }
426
427 ret = find_etypelist(context, ac, &etypes);
428 if (ret)
429 goto out;
430
431 ac->keytype = ETYPE_NULL;
432
433 if (etypes.val) {
434 size_t i;
435
436 for (i = 0; i < etypes.len; i++) {
437 if (krb5_enctype_valid(context, etypes.val[i]) == 0) {
438 ac->keytype = etypes.val[i];
439 break;
440 }
441 }
442 }
443
444 /* save key */
445 ret = krb5_copy_keyblock(context, &t->ticket.key, &ac->keyblock);
446 if (ret) goto out;
447
448 if (ap_req_options) {
449 *ap_req_options = 0;
450 if (ac->keytype != (krb5_enctype)ETYPE_NULL)
451 *ap_req_options |= AP_OPTS_USE_SUBKEY;
452 if (ap_req->ap_options.use_session_key)
453 *ap_req_options |= AP_OPTS_USE_SESSION_KEY;
454 if (ap_req->ap_options.mutual_required)
455 *ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
456 }
457
458 if(ticket)
459 *ticket = t;
460 else
461 krb5_free_ticket (context, t);
462 if (auth_context) {
463 if (*auth_context == NULL)
464 *auth_context = ac;
465 } else
466 krb5_auth_con_free (context, ac);
467 free_EtypeList(&etypes);
468 return 0;
469 out:
470 free_EtypeList(&etypes);
471 if (t)
472 krb5_free_ticket (context, t);
473 if (auth_context == NULL || *auth_context == NULL)
474 krb5_auth_con_free (context, ac);
475 return ret;
476 }
477
478 /*
479 *
480 */
481
482 struct krb5_rd_req_in_ctx_data {
483 krb5_keytab keytab;
484 krb5_keyblock *keyblock;
485 krb5_boolean check_pac;
486 };
487
488 struct krb5_rd_req_out_ctx_data {
489 krb5_keyblock *keyblock;
490 krb5_flags ap_req_options;
491 krb5_ticket *ticket;
492 krb5_principal server;
493 };
494
495 /**
496 * Allocate a krb5_rd_req_in_ctx as an input parameter to
497 * krb5_rd_req_ctx(). The caller should free the context with
498 * krb5_rd_req_in_ctx_free() when done with the context.
499 *
500 * @param context Keberos 5 context.
501 * @param ctx in ctx to krb5_rd_req_ctx().
502 *
503 * @return Kerberos 5 error code, see krb5_get_error_message().
504 *
505 * @ingroup krb5_auth
506 */
507
508 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_in_ctx_alloc(krb5_context context,krb5_rd_req_in_ctx * ctx)509 krb5_rd_req_in_ctx_alloc(krb5_context context, krb5_rd_req_in_ctx *ctx)
510 {
511 *ctx = calloc(1, sizeof(**ctx));
512 if (*ctx == NULL)
513 return krb5_enomem(context);
514 (*ctx)->check_pac = (context->flags & KRB5_CTX_F_CHECK_PAC) ? 1 : 0;
515 return 0;
516 }
517
518 /**
519 * Set the keytab that krb5_rd_req_ctx() will use.
520 *
521 * @param context Keberos 5 context.
522 * @param in in ctx to krb5_rd_req_ctx().
523 * @param keytab keytab that krb5_rd_req_ctx() will use, only copy the
524 * pointer, so the caller must free they keytab after
525 * krb5_rd_req_in_ctx_free() is called.
526 *
527 * @return Kerberos 5 error code, see krb5_get_error_message().
528 *
529 * @ingroup krb5_auth
530 */
531
532 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_in_set_keytab(krb5_context context,krb5_rd_req_in_ctx in,krb5_keytab keytab)533 krb5_rd_req_in_set_keytab(krb5_context context,
534 krb5_rd_req_in_ctx in,
535 krb5_keytab keytab)
536 {
537 in->keytab = keytab;
538 return 0;
539 }
540
541 /**
542 * Set if krb5_rq_red() is going to check the Windows PAC or not
543 *
544 * @param context Keberos 5 context.
545 * @param in krb5_rd_req_in_ctx to check the option on.
546 * @param flag flag to select if to check the pac (TRUE) or not (FALSE).
547 *
548 * @return Kerberos 5 error code, see krb5_get_error_message().
549 *
550 * @ingroup krb5_auth
551 */
552
553 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_in_set_pac_check(krb5_context context,krb5_rd_req_in_ctx in,krb5_boolean flag)554 krb5_rd_req_in_set_pac_check(krb5_context context,
555 krb5_rd_req_in_ctx in,
556 krb5_boolean flag)
557 {
558 in->check_pac = flag;
559 return 0;
560 }
561
562
563 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_in_set_keyblock(krb5_context context,krb5_rd_req_in_ctx in,krb5_keyblock * keyblock)564 krb5_rd_req_in_set_keyblock(krb5_context context,
565 krb5_rd_req_in_ctx in,
566 krb5_keyblock *keyblock)
567 {
568 in->keyblock = keyblock; /* XXX should make copy */
569 return 0;
570 }
571
572 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_out_get_ap_req_options(krb5_context context,krb5_rd_req_out_ctx out,krb5_flags * ap_req_options)573 krb5_rd_req_out_get_ap_req_options(krb5_context context,
574 krb5_rd_req_out_ctx out,
575 krb5_flags *ap_req_options)
576 {
577 *ap_req_options = out->ap_req_options;
578 return 0;
579 }
580
581 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_out_get_ticket(krb5_context context,krb5_rd_req_out_ctx out,krb5_ticket ** ticket)582 krb5_rd_req_out_get_ticket(krb5_context context,
583 krb5_rd_req_out_ctx out,
584 krb5_ticket **ticket)
585 {
586 return krb5_copy_ticket(context, out->ticket, ticket);
587 }
588
589 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_out_get_keyblock(krb5_context context,krb5_rd_req_out_ctx out,krb5_keyblock ** keyblock)590 krb5_rd_req_out_get_keyblock(krb5_context context,
591 krb5_rd_req_out_ctx out,
592 krb5_keyblock **keyblock)
593 {
594 return krb5_copy_keyblock(context, out->keyblock, keyblock);
595 }
596
597 /**
598 * Get the principal that was used in the request from the
599 * client. Might not match whats in the ticket if krb5_rd_req_ctx()
600 * searched in the keytab for a matching key.
601 *
602 * @param context a Kerberos 5 context.
603 * @param out a krb5_rd_req_out_ctx from krb5_rd_req_ctx().
604 * @param principal return principal, free with krb5_free_principal().
605 *
606 * @ingroup krb5_auth
607 */
608
609 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_out_get_server(krb5_context context,krb5_rd_req_out_ctx out,krb5_principal * principal)610 krb5_rd_req_out_get_server(krb5_context context,
611 krb5_rd_req_out_ctx out,
612 krb5_principal *principal)
613 {
614 return krb5_copy_principal(context, out->server, principal);
615 }
616
617 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_rd_req_in_ctx_free(krb5_context context,krb5_rd_req_in_ctx ctx)618 krb5_rd_req_in_ctx_free(krb5_context context, krb5_rd_req_in_ctx ctx)
619 {
620 free(ctx);
621 }
622
623 /**
624 * Free the krb5_rd_req_out_ctx.
625 *
626 * @param context Keberos 5 context.
627 * @param ctx krb5_rd_req_out_ctx context to free.
628 *
629 * @ingroup krb5_auth
630 */
631
632 KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_rd_req_out_ctx_free(krb5_context context,krb5_rd_req_out_ctx ctx)633 krb5_rd_req_out_ctx_free(krb5_context context, krb5_rd_req_out_ctx ctx)
634 {
635 if (ctx->ticket)
636 krb5_free_ticket(context, ctx->ticket);
637 if (ctx->keyblock)
638 krb5_free_keyblock(context, ctx->keyblock);
639 if (ctx->server)
640 krb5_free_principal(context, ctx->server);
641 free(ctx);
642 }
643
644 /**
645 * Process an AP_REQ message.
646 *
647 * @param context Kerberos 5 context.
648 * @param auth_context authentication context of the peer.
649 * @param inbuf the AP_REQ message, obtained for example with krb5_read_message().
650 * @param server server principal.
651 * @param keytab server keytab.
652 * @param ap_req_options set to the AP_REQ options. See the AP_OPTS_* defines.
653 * @param ticket on success, set to the authenticated client credentials.
654 * Must be deallocated with krb5_free_ticket(). If not
655 * interested, pass a NULL value.
656 *
657 * @return 0 to indicate success. Otherwise a Kerberos error code is
658 * returned, see krb5_get_error_message().
659 */
660 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req(krb5_context context,krb5_auth_context * auth_context,const krb5_data * inbuf,krb5_const_principal server,krb5_keytab keytab,krb5_flags * ap_req_options,krb5_ticket ** ticket)661 krb5_rd_req(krb5_context context,
662 krb5_auth_context *auth_context,
663 const krb5_data *inbuf,
664 krb5_const_principal server,
665 krb5_keytab keytab,
666 krb5_flags *ap_req_options,
667 krb5_ticket **ticket)
668 {
669 krb5_error_code ret;
670 krb5_rd_req_in_ctx in;
671 krb5_rd_req_out_ctx out;
672
673 ret = krb5_rd_req_in_ctx_alloc(context, &in);
674 if (ret)
675 return ret;
676
677 ret = krb5_rd_req_in_set_keytab(context, in, keytab);
678 if (ret) {
679 krb5_rd_req_in_ctx_free(context, in);
680 return ret;
681 }
682
683 ret = krb5_rd_req_ctx(context, auth_context, inbuf, server, in, &out);
684 krb5_rd_req_in_ctx_free(context, in);
685 if (ret)
686 return ret;
687
688 if (ap_req_options)
689 *ap_req_options = out->ap_req_options;
690 if (ticket) {
691 ret = krb5_copy_ticket(context, out->ticket, ticket);
692 if (ret)
693 goto out;
694 }
695
696 out:
697 krb5_rd_req_out_ctx_free(context, out);
698 return ret;
699 }
700
701 /*
702 *
703 */
704
705 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_with_keyblock(krb5_context context,krb5_auth_context * auth_context,const krb5_data * inbuf,krb5_const_principal server,krb5_keyblock * keyblock,krb5_flags * ap_req_options,krb5_ticket ** ticket)706 krb5_rd_req_with_keyblock(krb5_context context,
707 krb5_auth_context *auth_context,
708 const krb5_data *inbuf,
709 krb5_const_principal server,
710 krb5_keyblock *keyblock,
711 krb5_flags *ap_req_options,
712 krb5_ticket **ticket)
713 {
714 krb5_error_code ret;
715 krb5_rd_req_in_ctx in;
716 krb5_rd_req_out_ctx out;
717
718 ret = krb5_rd_req_in_ctx_alloc(context, &in);
719 if (ret)
720 return ret;
721
722 ret = krb5_rd_req_in_set_keyblock(context, in, keyblock);
723 if (ret) {
724 krb5_rd_req_in_ctx_free(context, in);
725 return ret;
726 }
727
728 ret = krb5_rd_req_ctx(context, auth_context, inbuf, server, in, &out);
729 krb5_rd_req_in_ctx_free(context, in);
730 if (ret)
731 return ret;
732
733 if (ap_req_options)
734 *ap_req_options = out->ap_req_options;
735 if (ticket) {
736 ret = krb5_copy_ticket(context, out->ticket, ticket);
737 if (ret)
738 goto out;
739 }
740
741 out:
742 krb5_rd_req_out_ctx_free(context, out);
743 return ret;
744 }
745
746 /*
747 *
748 */
749
750 static krb5_error_code
get_key_from_keytab(krb5_context context,krb5_ap_req * ap_req,krb5_const_principal server,krb5_keytab keytab,krb5_keyblock ** out_key)751 get_key_from_keytab(krb5_context context,
752 krb5_ap_req *ap_req,
753 krb5_const_principal server,
754 krb5_keytab keytab,
755 krb5_keyblock **out_key)
756 {
757 krb5_keytab_entry entry;
758 krb5_error_code ret;
759 int kvno;
760 krb5_keytab real_keytab;
761
762 if(keytab == NULL)
763 krb5_kt_default(context, &real_keytab);
764 else
765 real_keytab = keytab;
766
767 if (ap_req->ticket.enc_part.kvno)
768 kvno = *ap_req->ticket.enc_part.kvno;
769 else
770 kvno = 0;
771
772 ret = krb5_kt_get_entry (context,
773 real_keytab,
774 server,
775 kvno,
776 ap_req->ticket.enc_part.etype,
777 &entry);
778 if(ret == 0) {
779 ret = krb5_copy_keyblock(context, &entry.keyblock, out_key);
780 krb5_kt_free_entry(context, &entry);
781 }
782 if(keytab == NULL)
783 krb5_kt_close(context, real_keytab);
784
785 return ret;
786 }
787
788 /**
789 * The core server function that verify application authentication
790 * requests from clients.
791 *
792 * @param context Keberos 5 context.
793 * @param auth_context the authentication context, can be NULL, then
794 * default values for the authentication context will used.
795 * @param inbuf the (AP-REQ) authentication buffer
796 *
797 * @param server the server to authenticate to. If NULL the function
798 * will try to find any available credential in the keytab
799 * that will verify the reply. The function will prefer the
800 * server specified in the AP-REQ, but if
801 * there is no mach, it will try all keytab entries for a
802 * match. This has serious performance issues for large keytabs.
803 *
804 * @param inctx control the behavior of the function, if NULL, the
805 * default behavior is used.
806 * @param outctx the return outctx, free with krb5_rd_req_out_ctx_free().
807 * @return Kerberos 5 error code, see krb5_get_error_message().
808 *
809 * @ingroup krb5_auth
810 */
811
812 KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_ctx(krb5_context context,krb5_auth_context * auth_context,const krb5_data * inbuf,krb5_const_principal server,krb5_rd_req_in_ctx inctx,krb5_rd_req_out_ctx * outctx)813 krb5_rd_req_ctx(krb5_context context,
814 krb5_auth_context *auth_context,
815 const krb5_data *inbuf,
816 krb5_const_principal server,
817 krb5_rd_req_in_ctx inctx,
818 krb5_rd_req_out_ctx *outctx)
819 {
820 krb5_error_code ret;
821 krb5_ap_req ap_req;
822 krb5_rd_req_out_ctx o = NULL;
823 krb5_keytab id = NULL, keytab = NULL;
824 krb5_principal service = NULL;
825
826 *outctx = NULL;
827
828 o = calloc(1, sizeof(*o));
829 if (o == NULL)
830 return krb5_enomem(context);
831
832 if (*auth_context == NULL) {
833 ret = krb5_auth_con_init(context, auth_context);
834 if (ret)
835 goto out;
836 }
837
838 ret = krb5_decode_ap_req(context, inbuf, &ap_req);
839 if(ret)
840 goto out;
841
842 /* Save the principal that was in the request */
843 ret = _krb5_principalname2krb5_principal(context,
844 &o->server,
845 ap_req.ticket.sname,
846 ap_req.ticket.realm);
847 if (ret)
848 goto out;
849
850 if (ap_req.ap_options.use_session_key &&
851 (*auth_context)->keyblock == NULL) {
852 ret = KRB5KRB_AP_ERR_NOKEY;
853 krb5_set_error_message(context, ret,
854 N_("krb5_rd_req: user to user auth "
855 "without session key given", ""));
856 goto out;
857 }
858
859 if (inctx && inctx->keytab)
860 id = inctx->keytab;
861
862 if((*auth_context)->keyblock){
863 ret = krb5_copy_keyblock(context,
864 (*auth_context)->keyblock,
865 &o->keyblock);
866 if (ret)
867 goto out;
868 } else if(inctx && inctx->keyblock){
869 ret = krb5_copy_keyblock(context,
870 inctx->keyblock,
871 &o->keyblock);
872 if (ret)
873 goto out;
874 } else {
875
876 if(id == NULL) {
877 krb5_kt_default(context, &keytab);
878 id = keytab;
879 }
880 if (id == NULL)
881 goto out;
882
883 if (server == NULL) {
884 ret = _krb5_principalname2krb5_principal(context,
885 &service,
886 ap_req.ticket.sname,
887 ap_req.ticket.realm);
888 if (ret)
889 goto out;
890 server = service;
891 }
892
893 ret = get_key_from_keytab(context,
894 &ap_req,
895 server,
896 id,
897 &o->keyblock);
898 if (ret) {
899 /* If caller specified a server, fail. */
900 if (service == NULL && (context->flags & KRB5_CTX_F_RD_REQ_IGNORE) == 0)
901 goto out;
902 /* Otherwise, fall back to iterating over the keytab. This
903 * have serious performace issues for larger keytab.
904 */
905 o->keyblock = NULL;
906 }
907 }
908
909 if (o->keyblock) {
910 /*
911 * We got an exact keymatch, use that.
912 */
913
914 ret = krb5_verify_ap_req2(context,
915 auth_context,
916 &ap_req,
917 server,
918 o->keyblock,
919 0,
920 &o->ap_req_options,
921 &o->ticket,
922 KRB5_KU_AP_REQ_AUTH);
923
924 if (ret)
925 goto out;
926
927 } else {
928 /*
929 * Interate over keytab to find a key that can decrypt the request.
930 */
931
932 krb5_keytab_entry entry;
933 krb5_kt_cursor cursor;
934 int done = 0, kvno = 0;
935
936 memset(&cursor, 0, sizeof(cursor));
937
938 if (ap_req.ticket.enc_part.kvno)
939 kvno = *ap_req.ticket.enc_part.kvno;
940
941 ret = krb5_kt_start_seq_get(context, id, &cursor);
942 if (ret)
943 goto out;
944
945 done = 0;
946 while (!done) {
947 krb5_principal p;
948
949 ret = krb5_kt_next_entry(context, id, &entry, &cursor);
950 if (ret) {
951 _krb5_kt_principal_not_found(context, ret, id, o->server,
952 ap_req.ticket.enc_part.etype,
953 kvno);
954 break;
955 }
956
957 if (entry.keyblock.keytype != ap_req.ticket.enc_part.etype) {
958 krb5_kt_free_entry (context, &entry);
959 continue;
960 }
961
962 ret = krb5_verify_ap_req2(context,
963 auth_context,
964 &ap_req,
965 server,
966 &entry.keyblock,
967 0,
968 &o->ap_req_options,
969 &o->ticket,
970 KRB5_KU_AP_REQ_AUTH);
971 if (ret) {
972 krb5_kt_free_entry (context, &entry);
973 continue;
974 }
975
976 /*
977 * Found a match, save the keyblock for PAC processing,
978 * and update the service principal in the ticket to match
979 * whatever is in the keytab.
980 */
981
982 ret = krb5_copy_keyblock(context,
983 &entry.keyblock,
984 &o->keyblock);
985 if (ret) {
986 krb5_kt_free_entry (context, &entry);
987 break;
988 }
989
990 ret = krb5_copy_principal(context, entry.principal, &p);
991 if (ret) {
992 krb5_kt_free_entry (context, &entry);
993 break;
994 }
995 krb5_free_principal(context, o->ticket->server);
996 o->ticket->server = p;
997
998 krb5_kt_free_entry (context, &entry);
999
1000 done = 1;
1001 }
1002 krb5_kt_end_seq_get (context, id, &cursor);
1003 if (ret)
1004 goto out;
1005 }
1006
1007 /* If there is a PAC, verify its server signature */
1008 if (inctx == NULL || inctx->check_pac) {
1009 krb5_pac pac;
1010 krb5_data data;
1011
1012 ret = krb5_ticket_get_authorization_data_type(context,
1013 o->ticket,
1014 KRB5_AUTHDATA_WIN2K_PAC,
1015 &data);
1016 if (ret == 0) {
1017 ret = krb5_pac_parse(context, data.data, data.length, &pac);
1018 krb5_data_free(&data);
1019 if (ret)
1020 goto out;
1021
1022 ret = krb5_pac_verify(context,
1023 pac,
1024 o->ticket->ticket.authtime,
1025 o->ticket->client,
1026 o->keyblock,
1027 NULL);
1028 krb5_pac_free(context, pac);
1029 if (ret)
1030 goto out;
1031 } else
1032 ret = 0;
1033 }
1034 out:
1035
1036 if (ret || outctx == NULL) {
1037 krb5_rd_req_out_ctx_free(context, o);
1038 } else
1039 *outctx = o;
1040
1041 free_AP_REQ(&ap_req);
1042
1043 if (service)
1044 krb5_free_principal(context, service);
1045
1046 if (keytab)
1047 krb5_kt_close(context, keytab);
1048
1049 return ret;
1050 }
1051