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"
27 #include "lib/tsocket/tsocket.h"
28 #include "system/network.h"
29 #include "../lib/util/dlinklist.h"
30 #include "lib/ldb/include/ldb.h"
31 #include "auth/gensec/gensec.h"
32 #include "auth/credentials/credentials.h"
33 #include "auth/credentials/credentials_krb5.h"
34 #include "auth/auth.h"
35 #include "dsdb/samdb/samdb.h"
36 #include "../lib/util/util_ldb.h"
37 #include "rpc_server/dcerpc_server.h"
38 #include "rpc_server/samr/proto.h"
39 #include "libcli/security/security.h"
40 #include "param/param.h"
41 #include "kdc/kdc-glue.h"
43 /* Return true if there is a valid error packet formed in the error_blob */
44 static bool kpasswdd_make_error_reply(struct kdc_server
*kdc
,
47 const char *error_string
,
48 DATA_BLOB
*error_blob
)
50 char *error_string_utf8
;
53 DEBUG(result_code
? 3 : 10, ("kpasswdd: %s\n", error_string
));
55 if (!push_utf8_talloc(mem_ctx
, &error_string_utf8
, error_string
, &len
)) {
59 *error_blob
= data_blob_talloc(mem_ctx
, NULL
, 2 + len
+ 1);
60 if (!error_blob
->data
) {
63 RSSVAL(error_blob
->data
, 0, result_code
);
64 memcpy(error_blob
->data
+ 2, error_string_utf8
, len
+ 1);
68 /* Return true if there is a valid error packet formed in the error_blob */
69 static bool kpasswdd_make_unauth_error_reply(struct kdc_server
*kdc
,
72 const char *error_string
,
73 DATA_BLOB
*error_blob
)
77 DATA_BLOB error_bytes
;
78 krb5_data k5_error_bytes
, k5_error_blob
;
79 ret
= kpasswdd_make_error_reply(kdc
, mem_ctx
, result_code
, error_string
,
84 k5_error_bytes
.data
= error_bytes
.data
;
85 k5_error_bytes
.length
= error_bytes
.length
;
86 kret
= krb5_mk_error(kdc
->smb_krb5_context
->krb5_context
,
87 result_code
, NULL
, &k5_error_bytes
,
88 NULL
, NULL
, NULL
, NULL
, &k5_error_blob
);
92 *error_blob
= data_blob_talloc(mem_ctx
, k5_error_blob
.data
, k5_error_blob
.length
);
93 krb5_data_free(&k5_error_blob
);
94 if (!error_blob
->data
) {
100 static bool kpasswd_make_pwchange_reply(struct kdc_server
*kdc
,
103 enum samPwdChangeReason reject_reason
,
104 struct samr_DomInfo1
*dominfo
,
105 DATA_BLOB
*error_blob
)
107 if (NT_STATUS_EQUAL(status
, NT_STATUS_NO_SUCH_USER
)) {
108 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
109 KRB5_KPASSWD_ACCESSDENIED
,
110 "No such user when changing password",
113 if (NT_STATUS_EQUAL(status
, NT_STATUS_ACCESS_DENIED
)) {
114 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
115 KRB5_KPASSWD_ACCESSDENIED
,
116 "Not permitted to change password",
119 if (dominfo
&& NT_STATUS_EQUAL(status
, NT_STATUS_PASSWORD_RESTRICTION
)) {
120 const char *reject_string
;
121 switch (reject_reason
) {
122 case SAM_PWD_CHANGE_PASSWORD_TOO_SHORT
:
123 reject_string
= talloc_asprintf(mem_ctx
, "Password too short, password must be at least %d characters long",
124 dominfo
->min_password_length
);
126 case SAM_PWD_CHANGE_NOT_COMPLEX
:
127 reject_string
= "Password does not meet complexity requirements";
129 case SAM_PWD_CHANGE_PWD_IN_HISTORY
:
130 reject_string
= "Password is already in password history";
133 reject_string
= talloc_asprintf(mem_ctx
, "Password must be at least %d characters long, and cannot match any of your %d previous passwords",
134 dominfo
->min_password_length
, dominfo
->password_history_length
);
137 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
138 KRB5_KPASSWD_SOFTERROR
,
142 if (!NT_STATUS_IS_OK(status
)) {
143 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
144 KRB5_KPASSWD_HARDERROR
,
145 talloc_asprintf(mem_ctx
, "failed to set password: %s", nt_errstr(status
)),
149 return kpasswdd_make_error_reply(kdc
, mem_ctx
, KRB5_KPASSWD_SUCCESS
,
155 A user password change
157 Return true if there is a valid error packet (or success) formed in
160 static bool kpasswdd_change_password(struct kdc_server
*kdc
,
162 struct auth_session_info
*session_info
,
163 const DATA_BLOB
*password
,
167 enum samPwdChangeReason reject_reason
;
168 struct samr_DomInfo1
*dominfo
;
169 struct samr_Password
*oldLmHash
, *oldNtHash
;
170 struct ldb_context
*samdb
;
171 const char * const attrs
[] = { "dBCSPwd", "unicodePwd", NULL
};
172 struct ldb_message
**res
;
175 /* Fetch the old hashes to get the old password in order to perform
176 * the password change operation. Naturally it would be much better to
177 * have a password hash from an authentication around but this doesn't
178 * seem to be the case here. */
179 ret
= gendb_search(kdc
->samdb
, mem_ctx
, NULL
, &res
, attrs
,
180 "(&(objectClass=user)(sAMAccountName=%s))",
181 session_info
->server_info
->account_name
);
183 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
184 KRB5_KPASSWD_ACCESSDENIED
,
185 "No such user when changing password",
189 status
= samdb_result_passwords(mem_ctx
, kdc
->task
->lp_ctx
, res
[0],
190 &oldLmHash
, &oldNtHash
);
191 if (!NT_STATUS_IS_OK(status
)) {
192 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
193 KRB5_KPASSWD_ACCESSDENIED
,
194 "Not permitted to change password",
198 /* Start a SAM with user privileges for the password change */
199 samdb
= samdb_connect(mem_ctx
, kdc
->task
->event_ctx
, kdc
->task
->lp_ctx
,
202 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
203 KRB5_KPASSWD_HARDERROR
,
204 "Failed to open samdb",
208 DEBUG(3, ("Changing password of %s\\%s (%s)\n",
209 session_info
->server_info
->domain_name
,
210 session_info
->server_info
->account_name
,
211 dom_sid_string(mem_ctx
, &session_info
->security_token
->sids
[PRIMARY_USER_SID_INDEX
])));
213 /* Performs the password change */
214 status
= samdb_set_password_sid(samdb
, mem_ctx
,
215 &session_info
->security_token
->sids
[PRIMARY_USER_SID_INDEX
],
216 password
, NULL
, NULL
,
217 oldLmHash
, oldNtHash
, /* this is a user password change */
220 return kpasswd_make_pwchange_reply(kdc
, mem_ctx
,
228 static bool kpasswd_process_request(struct kdc_server
*kdc
,
230 struct gensec_security
*gensec_security
,
235 struct auth_session_info
*session_info
;
238 if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security
,
240 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
241 KRB5_KPASSWD_HARDERROR
,
242 "gensec_session_info failed!",
247 case KRB5_KPASSWD_VERS_CHANGEPW
:
250 if (!convert_string_talloc_convenience(mem_ctx
, lpcfg_iconv_convenience(kdc
->task
->lp_ctx
),
252 (const char *)input
->data
,
254 (void **)&password
.data
, &pw_len
, false)) {
257 password
.length
= pw_len
;
259 return kpasswdd_change_password(kdc
, mem_ctx
, session_info
,
262 case KRB5_KPASSWD_VERS_SETPW
:
265 enum samPwdChangeReason reject_reason
= SAM_PWD_CHANGE_NO_ERROR
;
266 struct samr_DomInfo1
*dominfo
= NULL
;
267 struct ldb_context
*samdb
;
268 krb5_context context
= kdc
->smb_krb5_context
->krb5_context
;
270 ChangePasswdDataMS chpw
;
273 krb5_principal principal
;
274 char *set_password_on_princ
;
275 struct ldb_dn
*set_password_on_dn
;
276 bool service_principal_name
= false;
281 ret
= decode_ChangePasswdDataMS(input
->data
, input
->length
,
284 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
285 KRB5_KPASSWD_MALFORMED
,
286 "failed to decode password change structure",
290 if (!convert_string_talloc_convenience(mem_ctx
, lpcfg_iconv_convenience(kdc
->task
->lp_ctx
),
292 (const char *)chpw
.newpasswd
.data
,
293 chpw
.newpasswd
.length
,
294 (void **)&password
.data
, &pw_len
, false)) {
295 free_ChangePasswdDataMS(&chpw
);
299 password
.length
= pw_len
;
301 if ((chpw
.targname
&& !chpw
.targrealm
)
302 || (!chpw
.targname
&& chpw
.targrealm
)) {
303 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
304 KRB5_KPASSWD_MALFORMED
,
305 "Realm and principal must be both present, or neither present",
308 if (chpw
.targname
&& chpw
.targrealm
) {
309 krb5_build_principal_ext(kdc
->smb_krb5_context
->krb5_context
,
310 &principal
, strlen(*chpw
.targrealm
), *chpw
.targrealm
, 0);
311 if (copy_PrincipalName(chpw
.targname
, &principal
->name
)) {
312 free_ChangePasswdDataMS(&chpw
);
313 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
314 KRB5_KPASSWD_MALFORMED
,
315 "failed to extract principal to set",
319 free_ChangePasswdDataMS(&chpw
);
320 return kpasswdd_change_password(kdc
, mem_ctx
, session_info
,
323 free_ChangePasswdDataMS(&chpw
);
325 if (principal
->name
.name_string
.len
>= 2) {
326 service_principal_name
= true;
328 /* We use this, rather than 'no realm' flag,
329 * as we don't want to accept a password
330 * change on a principal from another realm */
332 if (krb5_unparse_name_short(context
, principal
, &set_password_on_princ
) != 0) {
333 krb5_free_principal(context
, principal
);
334 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
335 KRB5_KPASSWD_MALFORMED
,
336 "krb5_unparse_name failed!",
340 if (krb5_unparse_name(context
, principal
, &set_password_on_princ
) != 0) {
341 krb5_free_principal(context
, principal
);
342 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
343 KRB5_KPASSWD_MALFORMED
,
344 "krb5_unparse_name failed!",
348 krb5_free_principal(context
, principal
);
350 samdb
= samdb_connect(mem_ctx
, kdc
->task
->event_ctx
, kdc
->task
->lp_ctx
, session_info
, 0);
352 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
353 KRB5_KPASSWD_HARDERROR
,
354 "Unable to open database!",
358 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
359 session_info
->server_info
->domain_name
,
360 session_info
->server_info
->account_name
,
361 dom_sid_string(mem_ctx
, &session_info
->security_token
->sids
[PRIMARY_USER_SID_INDEX
]),
362 set_password_on_princ
));
363 ret
= ldb_transaction_start(samdb
);
364 if (ret
!= LDB_SUCCESS
) {
365 status
= NT_STATUS_TRANSACTION_ABORTED
;
366 return kpasswd_make_pwchange_reply(kdc
, mem_ctx
,
368 SAM_PWD_CHANGE_NO_ERROR
,
373 if (service_principal_name
) {
374 status
= crack_service_principal_name(samdb
, mem_ctx
,
375 set_password_on_princ
,
376 &set_password_on_dn
, NULL
);
378 status
= crack_user_principal_name(samdb
, mem_ctx
,
379 set_password_on_princ
,
380 &set_password_on_dn
, NULL
);
382 free(set_password_on_princ
);
383 if (!NT_STATUS_IS_OK(status
)) {
384 ldb_transaction_cancel(samdb
);
385 return kpasswd_make_pwchange_reply(kdc
, mem_ctx
,
387 SAM_PWD_CHANGE_NO_ERROR
,
392 if (NT_STATUS_IS_OK(status
)) {
393 /* Admin password set */
394 status
= samdb_set_password(samdb
, mem_ctx
,
395 set_password_on_dn
, NULL
,
396 &password
, NULL
, NULL
,
397 NULL
, NULL
, /* this is not a user password change */
398 &reject_reason
, &dominfo
);
401 if (NT_STATUS_IS_OK(status
)) {
402 ret
= ldb_transaction_commit(samdb
);
403 if (ret
!= LDB_SUCCESS
) {
404 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
405 ldb_dn_get_linearized(set_password_on_dn
),
406 ldb_errstring(samdb
)));
407 status
= NT_STATUS_TRANSACTION_ABORTED
;
410 ldb_transaction_cancel(samdb
);
412 return kpasswd_make_pwchange_reply(kdc
, mem_ctx
,
419 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
420 KRB5_KPASSWD_BAD_VERSION
,
421 talloc_asprintf(mem_ctx
,
422 "Protocol version %u not supported",
428 enum kdc_process_ret
kpasswdd_process(struct kdc_server
*kdc
,
432 struct tsocket_address
*peer_addr
,
433 struct tsocket_address
*my_addr
,
437 const uint16_t header_len
= 6;
440 uint16_t krb_priv_len
;
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
);
454 return KDC_PROCESS_FAILED
;
458 talloc_free(tmp_ctx
);
459 return KDC_PROCESS_PROXY
;
462 /* Be parinoid. We need to ensure we don't just let the
463 * caller lead us into a buffer overflow */
464 if (input
->length
<= header_len
) {
465 talloc_free(tmp_ctx
);
466 return KDC_PROCESS_FAILED
;
469 len
= RSVAL(input
->data
, 0);
470 if (input
->length
!= len
) {
471 talloc_free(tmp_ctx
);
472 return KDC_PROCESS_FAILED
;
475 /* There are two different versions of this protocol so far,
476 * plus others in the standards pipe. Fortunetly they all
477 * take a very similar framing */
478 version
= RSVAL(input
->data
, 2);
479 ap_req_len
= RSVAL(input
->data
, 4);
480 if ((ap_req_len
>= len
) || (ap_req_len
+ header_len
) >= len
) {
481 talloc_free(tmp_ctx
);
482 return KDC_PROCESS_FAILED
;
485 krb_priv_len
= len
- ap_req_len
;
486 ap_req
= data_blob_const(&input
->data
[header_len
], ap_req_len
);
487 krb_priv_req
= data_blob_const(&input
->data
[header_len
+ ap_req_len
], krb_priv_len
);
489 server_credentials
= cli_credentials_init(tmp_ctx
);
490 if (!server_credentials
) {
491 DEBUG(1, ("Failed to init server credentials\n"));
492 talloc_free(tmp_ctx
);
493 return KDC_PROCESS_FAILED
;
496 /* We want the credentials subsystem to use the krb5 context
497 * we already have, rather than a new context */
498 cli_credentials_set_krb5_context(server_credentials
, kdc
->smb_krb5_context
);
499 cli_credentials_set_conf(server_credentials
, kdc
->task
->lp_ctx
);
501 keytab_name
= talloc_asprintf(server_credentials
, "HDB:samba4&%p", kdc
->base_ctx
);
503 cli_credentials_set_username(server_credentials
, "kadmin/changepw", CRED_SPECIFIED
);
504 ret
= cli_credentials_set_keytab_name(server_credentials
, kdc
->task
->lp_ctx
, keytab_name
, CRED_SPECIFIED
);
506 ret
= kpasswdd_make_unauth_error_reply(kdc
, mem_ctx
,
507 KRB5_KPASSWD_HARDERROR
,
508 talloc_asprintf(mem_ctx
,
509 "Failed to obtain server credentials for kadmin/changepw: %s\n",
510 nt_errstr(nt_status
)),
516 talloc_free(tmp_ctx
);
520 /* We don't strictly need to call this wrapper, and could call
521 * gensec_server_start directly, as we have no need for NTLM
522 * and we have a PAC, but this ensures that the wrapper can be
523 * safely extended for other helpful things in future */
524 nt_status
= samba_server_gensec_start(tmp_ctx
, kdc
->task
->event_ctx
,
530 if (!NT_STATUS_IS_OK(nt_status
)) {
531 talloc_free(tmp_ctx
);
532 return KDC_PROCESS_FAILED
;
535 /* The kerberos PRIV packets include these addresses. MIT
536 * clients check that they are present */
538 /* Skip this part for now, it breaks with a NetAPP filer and
539 * in any case where the client address is behind NAT. If
540 * older MIT clients need this, we might have to insert more
543 nt_status
= gensec_set_local_address(gensec_security
, peer_addr
);
544 if (!NT_STATUS_IS_OK(nt_status
)) {
545 talloc_free(tmp_ctx
);
546 return KDC_PROCESS_FAILED
;
550 nt_status
= gensec_set_local_address(gensec_security
, my_addr
);
551 if (!NT_STATUS_IS_OK(nt_status
)) {
552 talloc_free(tmp_ctx
);
553 return KDC_PROCESS_FAILED
;
556 /* We want the GENSEC wrap calls to generate PRIV tokens */
557 gensec_want_feature(gensec_security
, GENSEC_FEATURE_SEAL
);
559 nt_status
= gensec_start_mech_by_name(gensec_security
, "krb5");
560 if (!NT_STATUS_IS_OK(nt_status
)) {
561 talloc_free(tmp_ctx
);
562 return KDC_PROCESS_FAILED
;
565 /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
566 nt_status
= gensec_update(gensec_security
, tmp_ctx
, ap_req
, &ap_rep
);
567 if (!NT_STATUS_IS_OK(nt_status
) && !NT_STATUS_EQUAL(nt_status
, NT_STATUS_MORE_PROCESSING_REQUIRED
)) {
569 ret
= kpasswdd_make_unauth_error_reply(kdc
, mem_ctx
,
570 KRB5_KPASSWD_HARDERROR
,
571 talloc_asprintf(mem_ctx
,
572 "gensec_update failed: %s",
573 nt_errstr(nt_status
)),
579 talloc_free(tmp_ctx
);
580 return KDC_PROCESS_FAILED
;
583 /* Extract the data from the KRB-PRIV half of the message */
584 nt_status
= gensec_unwrap(gensec_security
, tmp_ctx
, &krb_priv_req
, &kpasswd_req
);
585 if (!NT_STATUS_IS_OK(nt_status
)) {
586 ret
= kpasswdd_make_unauth_error_reply(kdc
, mem_ctx
,
587 KRB5_KPASSWD_HARDERROR
,
588 talloc_asprintf(mem_ctx
,
589 "gensec_unwrap failed: %s",
590 nt_errstr(nt_status
)),
596 talloc_free(tmp_ctx
);
597 return KDC_PROCESS_FAILED
;
600 /* Figure out something to do with it (probably changing a password...) */
601 ret
= kpasswd_process_request(kdc
, tmp_ctx
,
604 &kpasswd_req
, &kpasswd_rep
);
607 talloc_free(tmp_ctx
);
608 return KDC_PROCESS_FAILED
;
611 /* And wrap up the reply: This ensures that the error message
612 * or success can be verified by the client */
613 nt_status
= gensec_wrap(gensec_security
, tmp_ctx
,
614 &kpasswd_rep
, &krb_priv_rep
);
615 if (!NT_STATUS_IS_OK(nt_status
)) {
616 ret
= kpasswdd_make_unauth_error_reply(kdc
, mem_ctx
,
617 KRB5_KPASSWD_HARDERROR
,
618 talloc_asprintf(mem_ctx
,
619 "gensec_wrap failed: %s",
620 nt_errstr(nt_status
)),
626 talloc_free(tmp_ctx
);
627 return KDC_PROCESS_FAILED
;
631 *reply
= data_blob_talloc(mem_ctx
, NULL
, krb_priv_rep
.length
+ ap_rep
.length
+ header_len
);
633 talloc_free(tmp_ctx
);
634 return KDC_PROCESS_FAILED
;
637 RSSVAL(reply
->data
, 0, reply
->length
);
638 RSSVAL(reply
->data
, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
639 RSSVAL(reply
->data
, 4, ap_rep
.length
);
640 memcpy(reply
->data
+ header_len
,
643 memcpy(reply
->data
+ header_len
+ ap_rep
.length
,
645 krb_priv_rep
.length
);
647 talloc_free(tmp_ctx
);
648 return KDC_PROCESS_OK
;