2 Unix SMB/CIFS implementation.
4 kpasswd Server implementation
6 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
7 Copyright (C) Andrew Tridgell 2005
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.
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.
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/>.
24 #include "smbd/service_task.h"
25 #include "lib/events/events.h"
26 #include "lib/socket/socket.h"
28 #include "system/network.h"
29 #include "lib/util/dlinklist.h"
30 #include "lib/ldb/include/ldb.h"
31 #include "heimdal/lib/krb5/krb5_locl.h"
32 #include "heimdal/lib/krb5/krb5-private.h"
33 #include "auth/gensec/gensec.h"
34 #include "auth/credentials/credentials.h"
35 #include "auth/credentials/credentials_krb5.h"
36 #include "auth/auth.h"
37 #include "dsdb/samdb/samdb.h"
38 #include "rpc_server/dcerpc_server.h"
39 #include "rpc_server/samr/proto.h"
40 #include "libcli/security/security.h"
42 /* hold information about one kdc socket */
43 struct kpasswd_socket {
44 struct socket_context *sock;
45 struct kdc_server *kdc;
48 /* a queue of outgoing replies that have been deferred */
49 struct kdc_reply *send_queue;
52 /* Return true if there is a valid error packet formed in the error_blob */
53 static BOOL kpasswdd_make_error_reply(struct kdc_server *kdc,
56 const char *error_string,
57 DATA_BLOB *error_blob)
59 char *error_string_utf8;
62 DEBUG(result_code ? 3 : 10, ("kpasswdd: %s\n", error_string));
64 len = push_utf8_talloc(mem_ctx, &error_string_utf8, error_string);
69 *error_blob = data_blob_talloc(mem_ctx, NULL, 2 + len + 1);
70 if (!error_blob->data) {
73 RSSVAL(error_blob->data, 0, result_code);
74 memcpy(error_blob->data + 2, error_string_utf8, len + 1);
78 /* Return true if there is a valid error packet formed in the error_blob */
79 static BOOL kpasswdd_make_unauth_error_reply(struct kdc_server *kdc,
82 const char *error_string,
83 DATA_BLOB *error_blob)
87 DATA_BLOB error_bytes;
88 krb5_data k5_error_bytes, k5_error_blob;
89 ret = kpasswdd_make_error_reply(kdc, mem_ctx, result_code, error_string,
94 k5_error_bytes.data = error_bytes.data;
95 k5_error_bytes.length = error_bytes.length;
96 kret = krb5_mk_error(kdc->smb_krb5_context->krb5_context,
97 result_code, NULL, &k5_error_bytes,
98 NULL, NULL, NULL, NULL, &k5_error_blob);
102 *error_blob = data_blob_talloc(mem_ctx, k5_error_blob.data, k5_error_blob.length);
103 krb5_data_free(&k5_error_blob);
104 if (!error_blob->data) {
110 static BOOL kpasswd_make_pwchange_reply(struct kdc_server *kdc,
113 enum samr_RejectReason reject_reason,
114 struct samr_DomInfo1 *dominfo,
115 DATA_BLOB *error_blob)
117 if (NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_USER)) {
118 return kpasswdd_make_error_reply(kdc, mem_ctx,
119 KRB5_KPASSWD_ACCESSDENIED,
120 "No such user when changing password",
123 if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
124 return kpasswdd_make_error_reply(kdc, mem_ctx,
125 KRB5_KPASSWD_ACCESSDENIED,
126 "Not permitted to change password",
129 if (dominfo && NT_STATUS_EQUAL(status, NT_STATUS_PASSWORD_RESTRICTION)) {
130 const char *reject_string;
131 switch (reject_reason) {
132 case SAMR_REJECT_TOO_SHORT:
133 reject_string = talloc_asprintf(mem_ctx, "Password too short, password must be at least %d characters long",
134 dominfo->min_password_length);
136 case SAMR_REJECT_COMPLEXITY:
137 reject_string = "Password does not meet complexity requirements";
139 case SAMR_REJECT_IN_HISTORY:
140 reject_string = "Password is already in password history";
142 case SAMR_REJECT_OTHER:
144 reject_string = talloc_asprintf(mem_ctx, "Password must be at least %d characters long, and cannot match any of your %d previous passwords",
145 dominfo->min_password_length, dominfo->password_history_length);
148 return kpasswdd_make_error_reply(kdc, mem_ctx,
149 KRB5_KPASSWD_SOFTERROR,
153 if (!NT_STATUS_IS_OK(status)) {
154 return kpasswdd_make_error_reply(kdc, mem_ctx,
155 KRB5_KPASSWD_HARDERROR,
156 talloc_asprintf(mem_ctx, "failed to set password: %s", nt_errstr(status)),
160 return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SUCCESS,
166 A user password change
168 Return true if there is a valid error packet (or sucess) formed in
171 static BOOL kpasswdd_change_password(struct kdc_server *kdc,
173 struct auth_session_info *session_info,
174 const char *password,
178 enum samr_RejectReason reject_reason;
179 struct samr_DomInfo1 *dominfo;
180 struct ldb_context *samdb;
182 samdb = samdb_connect(mem_ctx, system_session(mem_ctx));
184 return kpasswdd_make_error_reply(kdc, mem_ctx,
185 KRB5_KPASSWD_HARDERROR,
186 "Failed to open samdb",
190 DEBUG(3, ("Changing password of %s\\%s (%s)\n",
191 session_info->server_info->domain_name,
192 session_info->server_info->account_name,
193 dom_sid_string(mem_ctx, session_info->security_token->user_sid)));
195 /* User password change */
196 status = samdb_set_password_sid(samdb, mem_ctx,
197 session_info->security_token->user_sid,
198 password, NULL, NULL,
199 True, /* this is a user password change */
200 True, /* run restriction tests */
203 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
211 static BOOL kpasswd_process_request(struct kdc_server *kdc,
213 struct gensec_security *gensec_security,
218 struct auth_session_info *session_info;
219 if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security,
221 return kpasswdd_make_error_reply(kdc, mem_ctx,
222 KRB5_KPASSWD_HARDERROR,
223 "gensec_session_info failed!",
228 case KRB5_KPASSWD_VERS_CHANGEPW:
230 char *password = talloc_strndup(mem_ctx, (const char *)input->data, input->length);
234 return kpasswdd_change_password(kdc, mem_ctx, session_info,
238 case KRB5_KPASSWD_VERS_SETPW:
241 enum samr_RejectReason reject_reason = SAMR_REJECT_OTHER;
242 struct samr_DomInfo1 *dominfo = NULL;
243 struct ldb_context *samdb;
244 struct ldb_message *msg;
245 krb5_context context = kdc->smb_krb5_context->krb5_context;
247 ChangePasswdDataMS chpw;
250 krb5_principal principal;
251 char *set_password_on_princ;
252 struct ldb_dn *set_password_on_dn;
257 msg = ldb_msg_new(mem_ctx);
262 ret = decode_ChangePasswdDataMS(input->data, input->length,
265 return kpasswdd_make_error_reply(kdc, mem_ctx,
266 KRB5_KPASSWD_MALFORMED,
267 "failed to decode password change structure",
271 password = talloc_strndup(mem_ctx, chpw.newpasswd.data,
272 chpw.newpasswd.length);
274 free_ChangePasswdDataMS(&chpw);
277 if ((chpw.targname && !chpw.targrealm)
278 || (!chpw.targname && chpw.targrealm)) {
279 return kpasswdd_make_error_reply(kdc, mem_ctx,
280 KRB5_KPASSWD_MALFORMED,
281 "Realm and principal must be both present, or neither present",
284 if (chpw.targname && chpw.targrealm) {
285 if (_krb5_principalname2krb5_principal(kdc->smb_krb5_context->krb5_context,
286 &principal, *chpw.targname,
287 *chpw.targrealm) != 0) {
288 free_ChangePasswdDataMS(&chpw);
289 return kpasswdd_make_error_reply(kdc, mem_ctx,
290 KRB5_KPASSWD_MALFORMED,
291 "failed to extract principal to set",
296 free_ChangePasswdDataMS(&chpw);
297 return kpasswdd_change_password(kdc, mem_ctx, session_info,
300 free_ChangePasswdDataMS(&chpw);
302 if (krb5_unparse_name(context, principal, &set_password_on_princ) != 0) {
303 krb5_free_principal(context, principal);
304 return kpasswdd_make_error_reply(kdc, mem_ctx,
305 KRB5_KPASSWD_MALFORMED,
306 "krb5_unparse_name failed!",
310 krb5_free_principal(context, principal);
312 samdb = samdb_connect(mem_ctx, session_info);
314 return kpasswdd_make_error_reply(kdc, mem_ctx,
315 KRB5_KPASSWD_HARDERROR,
316 "Unable to open database!",
320 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
321 session_info->server_info->domain_name,
322 session_info->server_info->account_name,
323 dom_sid_string(mem_ctx, session_info->security_token->user_sid),
324 set_password_on_princ));
325 ret = ldb_transaction_start(samdb);
327 status = NT_STATUS_TRANSACTION_ABORTED;
328 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
335 status = crack_user_principal_name(samdb, mem_ctx,
336 set_password_on_princ,
337 &set_password_on_dn, NULL);
338 free(set_password_on_princ);
339 if (!NT_STATUS_IS_OK(status)) {
340 ldb_transaction_cancel(samdb);
341 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
348 msg = ldb_msg_new(mem_ctx);
350 ldb_transaction_cancel(samdb);
351 status = NT_STATUS_NO_MEMORY;
353 msg->dn = ldb_dn_copy(msg, set_password_on_dn);
355 status = NT_STATUS_NO_MEMORY;
359 if (NT_STATUS_IS_OK(status)) {
360 /* Admin password set */
361 status = samdb_set_password(samdb, mem_ctx,
362 set_password_on_dn, NULL,
363 msg, password, NULL, NULL,
364 False, /* this is not a user password change */
365 True, /* run restriction tests */
366 &reject_reason, &dominfo);
369 if (NT_STATUS_IS_OK(status)) {
370 /* modify the samdb record */
371 ret = samdb_replace(samdb, mem_ctx, msg);
373 DEBUG(2,("Failed to modify record to set password on %s: %s\n",
374 ldb_dn_get_linearized(msg->dn),
375 ldb_errstring(samdb)));
376 status = NT_STATUS_ACCESS_DENIED;
379 if (NT_STATUS_IS_OK(status)) {
380 ret = ldb_transaction_commit(samdb);
382 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
383 ldb_dn_get_linearized(msg->dn),
384 ldb_errstring(samdb)));
385 status = NT_STATUS_TRANSACTION_ABORTED;
388 ldb_transaction_cancel(samdb);
390 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
397 return kpasswdd_make_error_reply(kdc, mem_ctx,
398 KRB5_KPASSWD_BAD_VERSION,
399 talloc_asprintf(mem_ctx,
400 "Protocol version %u not supported",
407 BOOL kpasswdd_process(struct kdc_server *kdc,
411 struct socket_address *peer_addr,
412 struct socket_address *my_addr,
416 const uint16_t header_len = 6;
419 uint16_t krb_priv_len;
422 DATA_BLOB ap_req, krb_priv_req;
423 DATA_BLOB krb_priv_rep = data_blob(NULL, 0);
424 DATA_BLOB ap_rep = data_blob(NULL, 0);
425 DATA_BLOB kpasswd_req, kpasswd_rep;
426 struct cli_credentials *server_credentials;
427 struct gensec_security *gensec_security;
428 TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
434 /* Be parinoid. We need to ensure we don't just let the
435 * caller lead us into a buffer overflow */
436 if (input->length <= header_len) {
437 talloc_free(tmp_ctx);
441 len = RSVAL(input->data, 0);
442 if (input->length != len) {
443 talloc_free(tmp_ctx);
447 /* There are two different versions of this protocol so far,
448 * plus others in the standards pipe. Fortunetly they all
449 * take a very similar framing */
450 version = RSVAL(input->data, 2);
451 ap_req_len = RSVAL(input->data, 4);
452 if ((ap_req_len >= len) || (ap_req_len + header_len) >= len) {
453 talloc_free(tmp_ctx);
457 krb_priv_len = len - ap_req_len;
458 ap_req = data_blob_const(&input->data[header_len], ap_req_len);
459 krb_priv_req = data_blob_const(&input->data[header_len + ap_req_len], krb_priv_len);
461 nt_status = gensec_server_start(tmp_ctx, kdc->task->event_ctx, kdc->task->msg_ctx, &gensec_security);
462 if (!NT_STATUS_IS_OK(nt_status)) {
463 talloc_free(tmp_ctx);
467 server_credentials = cli_credentials_init(tmp_ctx);
468 if (!server_credentials) {
469 DEBUG(1, ("Failed to init server credentials\n"));
473 /* We want the credentials subsystem to use the krb5 context
474 * we already have, rather than a new context */
475 cli_credentials_set_krb5_context(server_credentials, kdc->smb_krb5_context);
476 cli_credentials_set_conf(server_credentials);
477 nt_status = cli_credentials_set_stored_principal(server_credentials, "kadmin/changepw");
478 if (!NT_STATUS_IS_OK(nt_status)) {
479 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
480 KRB5_KPASSWD_HARDERROR,
481 talloc_asprintf(mem_ctx,
482 "Failed to obtain server credentials for kadmin/changepw: %s\n",
483 nt_errstr(nt_status)),
489 talloc_free(tmp_ctx);
493 nt_status = gensec_set_credentials(gensec_security, server_credentials);
494 if (!NT_STATUS_IS_OK(nt_status)) {
495 talloc_free(tmp_ctx);
499 /* The kerberos PRIV packets include these addresses. MIT
500 * clients check that they are present */
501 nt_status = gensec_set_peer_addr(gensec_security, peer_addr);
502 if (!NT_STATUS_IS_OK(nt_status)) {
503 talloc_free(tmp_ctx);
506 nt_status = gensec_set_my_addr(gensec_security, my_addr);
507 if (!NT_STATUS_IS_OK(nt_status)) {
508 talloc_free(tmp_ctx);
512 /* We want the GENSEC wrap calls to generate PRIV tokens */
513 gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
515 nt_status = gensec_start_mech_by_name(gensec_security, "krb5");
516 if (!NT_STATUS_IS_OK(nt_status)) {
517 talloc_free(tmp_ctx);
521 /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
522 nt_status = gensec_update(gensec_security, tmp_ctx, ap_req, &ap_rep);
523 if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
525 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
526 KRB5_KPASSWD_HARDERROR,
527 talloc_asprintf(mem_ctx,
528 "gensec_update failed: %s",
529 nt_errstr(nt_status)),
535 talloc_free(tmp_ctx);
539 /* Extract the data from the KRB-PRIV half of the message */
540 nt_status = gensec_unwrap(gensec_security, tmp_ctx, &krb_priv_req, &kpasswd_req);
541 if (!NT_STATUS_IS_OK(nt_status)) {
542 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
543 KRB5_KPASSWD_HARDERROR,
544 talloc_asprintf(mem_ctx,
545 "gensec_unwrap failed: %s",
546 nt_errstr(nt_status)),
552 talloc_free(tmp_ctx);
556 /* Figure out something to do with it (probably changing a password...) */
557 ret = kpasswd_process_request(kdc, tmp_ctx,
560 &kpasswd_req, &kpasswd_rep);
566 /* And wrap up the reply: This ensures that the error message
567 * or success can be verified by the client */
568 nt_status = gensec_wrap(gensec_security, tmp_ctx,
569 &kpasswd_rep, &krb_priv_rep);
570 if (!NT_STATUS_IS_OK(nt_status)) {
571 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
572 KRB5_KPASSWD_HARDERROR,
573 talloc_asprintf(mem_ctx,
574 "gensec_wrap failed: %s",
575 nt_errstr(nt_status)),
581 talloc_free(tmp_ctx);
586 *reply = data_blob_talloc(mem_ctx, NULL, krb_priv_rep.length + ap_rep.length + header_len);
591 RSSVAL(reply->data, 0, reply->length);
592 RSSVAL(reply->data, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
593 RSSVAL(reply->data, 4, ap_rep.length);
594 memcpy(reply->data + header_len,
597 memcpy(reply->data + header_len + ap_rep.length,
599 krb_priv_rep.length);
601 talloc_free(tmp_ctx);