source: trunk/server/source4/kdc/kpasswdd.c@ 709

Last change on this file since 709 was 414, checked in by Herwig Bauernfeind, 16 years ago

Samba 3.5.0: Initial import
File size: 18.8 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3
4 kpasswd Server implementation
5
6 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
7 Copyright (C) Andrew Tridgell 2005
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>.
21*/
22
23#include "includes.h"
24#include "smbd/service_task.h"
25#include "lib/events/events.h"
26#include "lib/socket/socket.h"
27#include "system/network.h"
28#include "../lib/util/dlinklist.h"
29#include "lib/ldb/include/ldb.h"
30#include "auth/gensec/gensec.h"
31#include "auth/credentials/credentials.h"
32#include "auth/credentials/credentials_krb5.h"
33#include "auth/auth.h"
34#include "dsdb/samdb/samdb.h"
35#include "rpc_server/dcerpc_server.h"
36#include "rpc_server/samr/proto.h"
37#include "libcli/security/security.h"
38#include "param/param.h"
39#include "kdc/kdc.h"
40
41/* TODO: remove all SAMBA4_INTERNAL_HEIMDAL stuff from this file */
42#ifdef SAMBA4_INTERNAL_HEIMDAL
43#include "heimdal_build/kpasswdd-glue.h"
44#endif
45
46/* hold information about one kdc socket */
47struct kpasswd_socket {
48 struct socket_context *sock;
49 struct kdc_server *kdc;
50 struct tevent_fd *fde;
51
52 /* a queue of outgoing replies that have been deferred */
53 struct kdc_reply *send_queue;
54};
55
56/* Return true if there is a valid error packet formed in the error_blob */
57static bool kpasswdd_make_error_reply(struct kdc_server *kdc,
58 TALLOC_CTX *mem_ctx,
59 uint16_t result_code,
60 const char *error_string,
61 DATA_BLOB *error_blob)
62{
63 char *error_string_utf8;
64 size_t len;
65
66 DEBUG(result_code ? 3 : 10, ("kpasswdd: %s\n", error_string));
67
68 if (!push_utf8_talloc(mem_ctx, &error_string_utf8, error_string, &len)) {
69 return false;
70 }
71
72 *error_blob = data_blob_talloc(mem_ctx, NULL, 2 + len + 1);
73 if (!error_blob->data) {
74 return false;
75 }
76 RSSVAL(error_blob->data, 0, result_code);
77 memcpy(error_blob->data + 2, error_string_utf8, len + 1);
78 return true;
79}
80
81/* Return true if there is a valid error packet formed in the error_blob */
82static bool kpasswdd_make_unauth_error_reply(struct kdc_server *kdc,
83 TALLOC_CTX *mem_ctx,
84 uint16_t result_code,
85 const char *error_string,
86 DATA_BLOB *error_blob)
87{
88 bool ret;
89 int kret;
90 DATA_BLOB error_bytes;
91 krb5_data k5_error_bytes, k5_error_blob;
92 ret = kpasswdd_make_error_reply(kdc, mem_ctx, result_code, error_string,
93 &error_bytes);
94 if (!ret) {
95 return false;
96 }
97 k5_error_bytes.data = error_bytes.data;
98 k5_error_bytes.length = error_bytes.length;
99 kret = krb5_mk_error(kdc->smb_krb5_context->krb5_context,
100 result_code, NULL, &k5_error_bytes,
101 NULL, NULL, NULL, NULL, &k5_error_blob);
102 if (kret) {
103 return false;
104 }
105 *error_blob = data_blob_talloc(mem_ctx, k5_error_blob.data, k5_error_blob.length);
106 krb5_data_free(&k5_error_blob);
107 if (!error_blob->data) {
108 return false;
109 }
110 return true;
111}
112
113static bool kpasswd_make_pwchange_reply(struct kdc_server *kdc,
114 TALLOC_CTX *mem_ctx,
115 NTSTATUS status,
116 enum samr_RejectReason reject_reason,
117 struct samr_DomInfo1 *dominfo,
118 DATA_BLOB *error_blob)
119{
120 if (NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_USER)) {
121 return kpasswdd_make_error_reply(kdc, mem_ctx,
122 KRB5_KPASSWD_ACCESSDENIED,
123 "No such user when changing password",
124 error_blob);
125 }
126 if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
127 return kpasswdd_make_error_reply(kdc, mem_ctx,
128 KRB5_KPASSWD_ACCESSDENIED,
129 "Not permitted to change password",
130 error_blob);
131 }
132 if (dominfo && NT_STATUS_EQUAL(status, NT_STATUS_PASSWORD_RESTRICTION)) {
133 const char *reject_string;
134 switch (reject_reason) {
135 case SAMR_REJECT_TOO_SHORT:
136 reject_string = talloc_asprintf(mem_ctx, "Password too short, password must be at least %d characters long",
137 dominfo->min_password_length);
138 break;
139 case SAMR_REJECT_COMPLEXITY:
140 reject_string = "Password does not meet complexity requirements";
141 break;
142 case SAMR_REJECT_IN_HISTORY:
143 reject_string = "Password is already in password history";
144 break;
145 case SAMR_REJECT_OTHER:
146 default:
147 reject_string = talloc_asprintf(mem_ctx, "Password must be at least %d characters long, and cannot match any of your %d previous passwords",
148 dominfo->min_password_length, dominfo->password_history_length);
149 break;
150 }
151 return kpasswdd_make_error_reply(kdc, mem_ctx,
152 KRB5_KPASSWD_SOFTERROR,
153 reject_string,
154 error_blob);
155 }
156 if (!NT_STATUS_IS_OK(status)) {
157 return kpasswdd_make_error_reply(kdc, mem_ctx,
158 KRB5_KPASSWD_HARDERROR,
159 talloc_asprintf(mem_ctx, "failed to set password: %s", nt_errstr(status)),
160 error_blob);
161
162 }
163 return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SUCCESS,
164 "Password changed",
165 error_blob);
166}
167
168/*
169 A user password change
170
171 Return true if there is a valid error packet (or sucess) formed in
172 the error_blob
173*/
174static bool kpasswdd_change_password(struct kdc_server *kdc,
175 TALLOC_CTX *mem_ctx,
176 struct auth_session_info *session_info,
177 const DATA_BLOB *password,
178 DATA_BLOB *reply)
179{
180 NTSTATUS status;
181 enum samr_RejectReason reject_reason;
182 struct samr_DomInfo1 *dominfo;
183 struct ldb_context *samdb;
184
185 samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, system_session(mem_ctx, kdc->task->lp_ctx));
186 if (!samdb) {
187 return kpasswdd_make_error_reply(kdc, mem_ctx,
188 KRB5_KPASSWD_HARDERROR,
189 "Failed to open samdb",
190 reply);
191 }
192
193 DEBUG(3, ("Changing password of %s\\%s (%s)\n",
194 session_info->server_info->domain_name,
195 session_info->server_info->account_name,
196 dom_sid_string(mem_ctx, session_info->security_token->user_sid)));
197
198 /* User password change */
199 status = samdb_set_password_sid(samdb, mem_ctx,
200 session_info->security_token->user_sid,
201 password, NULL, NULL,
202 true, /* this is a user password change */
203 &reject_reason,
204 &dominfo);
205 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
206 status,
207 reject_reason,
208 dominfo,
209 reply);
210
211}
212
213static bool kpasswd_process_request(struct kdc_server *kdc,
214 TALLOC_CTX *mem_ctx,
215 struct gensec_security *gensec_security,
216 uint16_t version,
217 DATA_BLOB *input,
218 DATA_BLOB *reply)
219{
220 struct auth_session_info *session_info;
221 size_t pw_len;
222
223 if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security,
224 &session_info))) {
225 return kpasswdd_make_error_reply(kdc, mem_ctx,
226 KRB5_KPASSWD_HARDERROR,
227 "gensec_session_info failed!",
228 reply);
229 }
230
231 switch (version) {
232 case KRB5_KPASSWD_VERS_CHANGEPW:
233 {
234 DATA_BLOB password;
235 if (!convert_string_talloc_convenience(mem_ctx, lp_iconv_convenience(kdc->task->lp_ctx),
236 CH_UTF8, CH_UTF16,
237 (const char *)input->data,
238 input->length,
239 (void **)&password.data, &pw_len, false)) {
240 return false;
241 }
242 password.length = pw_len;
243
244 return kpasswdd_change_password(kdc, mem_ctx, session_info,
245 &password, reply);
246 break;
247 }
248 case KRB5_KPASSWD_VERS_SETPW:
249 {
250 NTSTATUS status;
251 enum samr_RejectReason reject_reason = SAMR_REJECT_OTHER;
252 struct samr_DomInfo1 *dominfo = NULL;
253 struct ldb_context *samdb;
254 struct ldb_message *msg;
255 krb5_context context = kdc->smb_krb5_context->krb5_context;
256
257 ChangePasswdDataMS chpw;
258 DATA_BLOB password;
259
260 krb5_principal principal;
261 char *set_password_on_princ;
262 struct ldb_dn *set_password_on_dn;
263
264 size_t len;
265 int ret;
266
267 msg = ldb_msg_new(mem_ctx);
268 if (!msg) {
269 return false;
270 }
271
272 ret = decode_ChangePasswdDataMS(input->data, input->length,
273 &chpw, &len);
274 if (ret) {
275 return kpasswdd_make_error_reply(kdc, mem_ctx,
276 KRB5_KPASSWD_MALFORMED,
277 "failed to decode password change structure",
278 reply);
279 }
280
281 if (!convert_string_talloc_convenience(mem_ctx, lp_iconv_convenience(kdc->task->lp_ctx),
282 CH_UTF8, CH_UTF16,
283 (const char *)chpw.newpasswd.data,
284 chpw.newpasswd.length,
285 (void **)&password.data, &pw_len, false)) {
286 free_ChangePasswdDataMS(&chpw);
287 return false;
288 }
289
290 password.length = pw_len;
291
292 if ((chpw.targname && !chpw.targrealm)
293 || (!chpw.targname && chpw.targrealm)) {
294 return kpasswdd_make_error_reply(kdc, mem_ctx,
295 KRB5_KPASSWD_MALFORMED,
296 "Realm and principal must be both present, or neither present",
297 reply);
298 }
299 if (chpw.targname && chpw.targrealm) {
300#ifdef SAMBA4_INTERNAL_HEIMDAL
301 if (_krb5_principalname2krb5_principal(kdc->smb_krb5_context->krb5_context,
302 &principal, *chpw.targname,
303 *chpw.targrealm) != 0) {
304 free_ChangePasswdDataMS(&chpw);
305 return kpasswdd_make_error_reply(kdc, mem_ctx,
306 KRB5_KPASSWD_MALFORMED,
307 "failed to extract principal to set",
308 reply);
309
310 }
311#else /* SAMBA4_INTERNAL_HEIMDAL */
312 return kpasswdd_make_error_reply(kdc, mem_ctx,
313 KRB5_KPASSWD_BAD_VERSION,
314 "Operation Not Implemented",
315 reply);
316#endif /* SAMBA4_INTERNAL_HEIMDAL */
317 } else {
318 free_ChangePasswdDataMS(&chpw);
319 return kpasswdd_change_password(kdc, mem_ctx, session_info,
320 &password, reply);
321 }
322 free_ChangePasswdDataMS(&chpw);
323
324 if (krb5_unparse_name(context, principal, &set_password_on_princ) != 0) {
325 krb5_free_principal(context, principal);
326 return kpasswdd_make_error_reply(kdc, mem_ctx,
327 KRB5_KPASSWD_MALFORMED,
328 "krb5_unparse_name failed!",
329 reply);
330 }
331
332 krb5_free_principal(context, principal);
333
334 samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, session_info);
335 if (!samdb) {
336 return kpasswdd_make_error_reply(kdc, mem_ctx,
337 KRB5_KPASSWD_HARDERROR,
338 "Unable to open database!",
339 reply);
340 }
341
342 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
343 session_info->server_info->domain_name,
344 session_info->server_info->account_name,
345 dom_sid_string(mem_ctx, session_info->security_token->user_sid),
346 set_password_on_princ));
347 ret = ldb_transaction_start(samdb);
348 if (ret) {
349 status = NT_STATUS_TRANSACTION_ABORTED;
350 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
351 status,
352 SAMR_REJECT_OTHER,
353 NULL,
354 reply);
355 }
356
357 status = crack_user_principal_name(samdb, mem_ctx,
358 set_password_on_princ,
359 &set_password_on_dn, NULL);
360 free(set_password_on_princ);
361 if (!NT_STATUS_IS_OK(status)) {
362 ldb_transaction_cancel(samdb);
363 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
364 status,
365 SAMR_REJECT_OTHER,
366 NULL,
367 reply);
368 }
369
370 msg = ldb_msg_new(mem_ctx);
371 if (msg == NULL) {
372 ldb_transaction_cancel(samdb);
373 status = NT_STATUS_NO_MEMORY;
374 } else {
375 msg->dn = ldb_dn_copy(msg, set_password_on_dn);
376 if (!msg->dn) {
377 status = NT_STATUS_NO_MEMORY;
378 }
379 }
380
381 if (NT_STATUS_IS_OK(status)) {
382 /* Admin password set */
383 status = samdb_set_password(samdb, mem_ctx,
384 set_password_on_dn, NULL,
385 msg, &password, NULL, NULL,
386 false, /* this is not a user password change */
387 &reject_reason, &dominfo);
388 }
389
390 if (NT_STATUS_IS_OK(status)) {
391 /* modify the samdb record */
392 ret = samdb_replace(samdb, mem_ctx, msg);
393 if (ret != 0) {
394 DEBUG(2,("Failed to modify record to set password on %s: %s\n",
395 ldb_dn_get_linearized(msg->dn),
396 ldb_errstring(samdb)));
397 status = NT_STATUS_ACCESS_DENIED;
398 }
399 }
400 if (NT_STATUS_IS_OK(status)) {
401 ret = ldb_transaction_commit(samdb);
402 if (ret != 0) {
403 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
404 ldb_dn_get_linearized(msg->dn),
405 ldb_errstring(samdb)));
406 status = NT_STATUS_TRANSACTION_ABORTED;
407 }
408 } else {
409 ldb_transaction_cancel(samdb);
410 }
411 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
412 status,
413 reject_reason,
414 dominfo,
415 reply);
416 }
417 default:
418 return kpasswdd_make_error_reply(kdc, mem_ctx,
419 KRB5_KPASSWD_BAD_VERSION,
420 talloc_asprintf(mem_ctx,
421 "Protocol version %u not supported",
422 version),
423 reply);
424 }
425 return true;
426}
427
428bool kpasswdd_process(struct kdc_server *kdc,
429 TALLOC_CTX *mem_ctx,
430 DATA_BLOB *input,
431 DATA_BLOB *reply,
432 struct socket_address *peer_addr,
433 struct socket_address *my_addr,
434 int datagram_reply)
435{
436 bool ret;
437 const uint16_t header_len = 6;
438 uint16_t len;
439 uint16_t ap_req_len;
440 uint16_t krb_priv_len;
441 uint16_t version;
442 NTSTATUS nt_status;
443 DATA_BLOB ap_req, krb_priv_req;
444 DATA_BLOB krb_priv_rep = data_blob(NULL, 0);
445 DATA_BLOB ap_rep = data_blob(NULL, 0);
446 DATA_BLOB kpasswd_req, kpasswd_rep;
447 struct cli_credentials *server_credentials;
448 struct gensec_security *gensec_security;
449 TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
450
451 char *keytab_name;
452
453 if (!tmp_ctx) {
454 return false;
455 }
456
457 /* Be parinoid. We need to ensure we don't just let the
458 * caller lead us into a buffer overflow */
459 if (input->length <= header_len) {
460 talloc_free(tmp_ctx);
461 return false;
462 }
463
464 len = RSVAL(input->data, 0);
465 if (input->length != len) {
466 talloc_free(tmp_ctx);
467 return false;
468 }
469
470 /* There are two different versions of this protocol so far,
471 * plus others in the standards pipe. Fortunetly they all
472 * take a very similar framing */
473 version = RSVAL(input->data, 2);
474 ap_req_len = RSVAL(input->data, 4);
475 if ((ap_req_len >= len) || (ap_req_len + header_len) >= len) {
476 talloc_free(tmp_ctx);
477 return false;
478 }
479
480 krb_priv_len = len - ap_req_len;
481 ap_req = data_blob_const(&input->data[header_len], ap_req_len);
482 krb_priv_req = data_blob_const(&input->data[header_len + ap_req_len], krb_priv_len);
483
484 server_credentials = cli_credentials_init(tmp_ctx);
485 if (!server_credentials) {
486 DEBUG(1, ("Failed to init server credentials\n"));
487 return false;
488 }
489
490 /* We want the credentials subsystem to use the krb5 context
491 * we already have, rather than a new context */
492 cli_credentials_set_krb5_context(server_credentials, kdc->smb_krb5_context);
493 cli_credentials_set_conf(server_credentials, kdc->task->lp_ctx);
494
495 keytab_name = talloc_asprintf(server_credentials, "HDB:samba4&%p", kdc->hdb_samba4_context);
496
497 cli_credentials_set_username(server_credentials, "kadmin/changepw", CRED_SPECIFIED);
498 ret = cli_credentials_set_keytab_name(server_credentials, kdc->task->event_ctx, kdc->task->lp_ctx, keytab_name, CRED_SPECIFIED);
499 if (ret != 0) {
500 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
501 KRB5_KPASSWD_HARDERROR,
502 talloc_asprintf(mem_ctx,
503 "Failed to obtain server credentials for kadmin/changepw: %s\n",
504 nt_errstr(nt_status)),
505 &krb_priv_rep);
506 ap_rep.length = 0;
507 if (ret) {
508 goto reply;
509 }
510 talloc_free(tmp_ctx);
511 return ret;
512 }
513
514 /* We don't strictly need to call this wrapper, and could call
515 * gensec_server_start directly, as we have no need for NTLM
516 * and we have a PAC, but this ensures that the wrapper can be
517 * safely extended for other helpful things in future */
518 nt_status = samba_server_gensec_start(tmp_ctx, kdc->task->event_ctx,
519 kdc->task->msg_ctx,
520 kdc->task->lp_ctx,
521 server_credentials,
522 "kpasswd",
523 &gensec_security);
524 if (!NT_STATUS_IS_OK(nt_status)) {
525 talloc_free(tmp_ctx);
526 return false;
527 }
528
529 /* The kerberos PRIV packets include these addresses. MIT
530 * clients check that they are present */
531#if 0
532 /* Skip this part for now, it breaks with a NetAPP filer and
533 * in any case where the client address is behind NAT. If
534 * older MIT clients need this, we might have to insert more
535 * complex code */
536
537 nt_status = gensec_set_peer_addr(gensec_security, peer_addr);
538 if (!NT_STATUS_IS_OK(nt_status)) {
539 talloc_free(tmp_ctx);
540 return false;
541 }
542#endif
543
544 nt_status = gensec_set_my_addr(gensec_security, my_addr);
545 if (!NT_STATUS_IS_OK(nt_status)) {
546 talloc_free(tmp_ctx);
547 return false;
548 }
549
550 /* We want the GENSEC wrap calls to generate PRIV tokens */
551 gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
552
553 nt_status = gensec_start_mech_by_name(gensec_security, "krb5");
554 if (!NT_STATUS_IS_OK(nt_status)) {
555 talloc_free(tmp_ctx);
556 return false;
557 }
558
559 /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
560 nt_status = gensec_update(gensec_security, tmp_ctx, ap_req, &ap_rep);
561 if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
562
563 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
564 KRB5_KPASSWD_HARDERROR,
565 talloc_asprintf(mem_ctx,
566 "gensec_update failed: %s",
567 nt_errstr(nt_status)),
568 &krb_priv_rep);
569 ap_rep.length = 0;
570 if (ret) {
571 goto reply;
572 }
573 talloc_free(tmp_ctx);
574 return ret;
575 }
576
577 /* Extract the data from the KRB-PRIV half of the message */
578 nt_status = gensec_unwrap(gensec_security, tmp_ctx, &krb_priv_req, &kpasswd_req);
579 if (!NT_STATUS_IS_OK(nt_status)) {
580 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
581 KRB5_KPASSWD_HARDERROR,
582 talloc_asprintf(mem_ctx,
583 "gensec_unwrap failed: %s",
584 nt_errstr(nt_status)),
585 &krb_priv_rep);
586 ap_rep.length = 0;
587 if (ret) {
588 goto reply;
589 }
590 talloc_free(tmp_ctx);
591 return ret;
592 }
593
594 /* Figure out something to do with it (probably changing a password...) */
595 ret = kpasswd_process_request(kdc, tmp_ctx,
596 gensec_security,
597 version,
598 &kpasswd_req, &kpasswd_rep);
599 if (!ret) {
600 /* Argh! */
601 return false;
602 }
603
604 /* And wrap up the reply: This ensures that the error message
605 * or success can be verified by the client */
606 nt_status = gensec_wrap(gensec_security, tmp_ctx,
607 &kpasswd_rep, &krb_priv_rep);
608 if (!NT_STATUS_IS_OK(nt_status)) {
609 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
610 KRB5_KPASSWD_HARDERROR,
611 talloc_asprintf(mem_ctx,
612 "gensec_wrap failed: %s",
613 nt_errstr(nt_status)),
614 &krb_priv_rep);
615 ap_rep.length = 0;
616 if (ret) {
617 goto reply;
618 }
619 talloc_free(tmp_ctx);
620 return ret;
621 }
622
623reply:
624 *reply = data_blob_talloc(mem_ctx, NULL, krb_priv_rep.length + ap_rep.length + header_len);
625 if (!reply->data) {
626 return false;
627 }
628
629 RSSVAL(reply->data, 0, reply->length);
630 RSSVAL(reply->data, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
631 RSSVAL(reply->data, 4, ap_rep.length);
632 memcpy(reply->data + header_len,
633 ap_rep.data,
634 ap_rep.length);
635 memcpy(reply->data + header_len + ap_rep.length,
636 krb_priv_rep.data,
637 krb_priv_rep.length);
638
639 talloc_free(tmp_ctx);
640 return ret;
641}
642
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