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 "auth/gensec/gensec.h"
26 #include "auth/credentials/credentials.h"
27 #include "auth/auth.h"
28 #include "dsdb/samdb/samdb.h"
29 #include "../lib/util/util_ldb.h"
30 #include "libcli/security/security.h"
31 #include "param/param.h"
32 #include "kdc/kdc-glue.h"
33 #include "dsdb/common/util.h"
35 /* Return true if there is a valid error packet formed in the error_blob */
36 static bool kpasswdd_make_error_reply(struct kdc_server
*kdc
,
39 const char *error_string
,
40 DATA_BLOB
*error_blob
)
42 char *error_string_utf8
;
45 DEBUG(result_code
? 3 : 10, ("kpasswdd: %s\n", error_string
));
47 if (!push_utf8_talloc(mem_ctx
, &error_string_utf8
, error_string
, &len
)) {
51 *error_blob
= data_blob_talloc(mem_ctx
, NULL
, 2 + len
+ 1);
52 if (!error_blob
->data
) {
55 RSSVAL(error_blob
->data
, 0, result_code
);
56 memcpy(error_blob
->data
+ 2, error_string_utf8
, len
+ 1);
60 /* Return true if there is a valid error packet formed in the error_blob */
61 static bool kpasswdd_make_unauth_error_reply(struct kdc_server
*kdc
,
64 const char *error_string
,
65 DATA_BLOB
*error_blob
)
69 DATA_BLOB error_bytes
;
70 krb5_data k5_error_bytes
, k5_error_blob
;
71 ret
= kpasswdd_make_error_reply(kdc
, mem_ctx
, result_code
, error_string
,
76 k5_error_bytes
.data
= error_bytes
.data
;
77 k5_error_bytes
.length
= error_bytes
.length
;
78 kret
= krb5_mk_error(kdc
->smb_krb5_context
->krb5_context
,
79 result_code
, NULL
, &k5_error_bytes
,
80 NULL
, NULL
, NULL
, NULL
, &k5_error_blob
);
84 *error_blob
= data_blob_talloc(mem_ctx
, k5_error_blob
.data
, k5_error_blob
.length
);
85 krb5_data_free(&k5_error_blob
);
86 if (!error_blob
->data
) {
92 static bool kpasswd_make_pwchange_reply(struct kdc_server
*kdc
,
95 enum samPwdChangeReason reject_reason
,
96 struct samr_DomInfo1
*dominfo
,
97 DATA_BLOB
*error_blob
)
99 if (NT_STATUS_EQUAL(status
, NT_STATUS_NO_SUCH_USER
)) {
100 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
101 KRB5_KPASSWD_ACCESSDENIED
,
102 "No such user when changing password",
105 if (NT_STATUS_EQUAL(status
, NT_STATUS_ACCESS_DENIED
)) {
106 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
107 KRB5_KPASSWD_ACCESSDENIED
,
108 "Not permitted to change password",
111 if (dominfo
&& NT_STATUS_EQUAL(status
, NT_STATUS_PASSWORD_RESTRICTION
)) {
112 const char *reject_string
;
113 switch (reject_reason
) {
114 case SAM_PWD_CHANGE_PASSWORD_TOO_SHORT
:
115 reject_string
= talloc_asprintf(mem_ctx
, "Password too short, password must be at least %d characters long.",
116 dominfo
->min_password_length
);
118 case SAM_PWD_CHANGE_NOT_COMPLEX
:
119 reject_string
= "Password does not meet complexity requirements";
121 case SAM_PWD_CHANGE_PWD_IN_HISTORY
:
122 reject_string
= talloc_asprintf(mem_ctx
, "Password is already in password history. New password must not match any of your %d previous passwords.",
123 dominfo
->password_history_length
);
126 reject_string
= "Password change rejected, password changes may not be permitted on this account, or the minimum password age may not have elapsed.";
129 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
130 KRB5_KPASSWD_SOFTERROR
,
134 if (!NT_STATUS_IS_OK(status
)) {
135 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
136 KRB5_KPASSWD_HARDERROR
,
137 talloc_asprintf(mem_ctx
, "failed to set password: %s", nt_errstr(status
)),
141 return kpasswdd_make_error_reply(kdc
, mem_ctx
, KRB5_KPASSWD_SUCCESS
,
147 A user password change
149 Return true if there is a valid error packet (or success) formed in
152 static bool kpasswdd_change_password(struct kdc_server
*kdc
,
154 struct auth_session_info
*session_info
,
155 const DATA_BLOB
*password
,
159 enum samPwdChangeReason reject_reason
;
160 struct samr_DomInfo1
*dominfo
;
161 struct samr_Password
*oldLmHash
, *oldNtHash
;
162 struct ldb_context
*samdb
;
163 const char * const attrs
[] = { "dBCSPwd", "unicodePwd", NULL
};
164 struct ldb_message
*msg
;
167 /* Fetch the old hashes to get the old password in order to perform
168 * the password change operation. Naturally it would be much better to
169 * have a password hash from an authentication around but this doesn't
170 * seem to be the case here. */
171 ret
= dsdb_search_one(kdc
->samdb
, mem_ctx
, &msg
, ldb_get_default_basedn(kdc
->samdb
),
174 DSDB_SEARCH_NO_GLOBAL_CATALOG
,
175 "(&(objectClass=user)(sAMAccountName=%s))",
176 session_info
->info
->account_name
);
177 if (ret
!= LDB_SUCCESS
) {
178 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
179 KRB5_KPASSWD_ACCESSDENIED
,
180 "No such user when changing password",
184 status
= samdb_result_passwords(mem_ctx
, kdc
->task
->lp_ctx
, msg
,
185 &oldLmHash
, &oldNtHash
);
186 if (!NT_STATUS_IS_OK(status
)) {
187 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
188 KRB5_KPASSWD_ACCESSDENIED
,
189 "Not permitted to change password",
193 /* Start a SAM with user privileges for the password change */
194 samdb
= samdb_connect(mem_ctx
, kdc
->task
->event_ctx
, kdc
->task
->lp_ctx
,
197 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
198 KRB5_KPASSWD_HARDERROR
,
199 "Failed to open samdb",
203 DEBUG(3, ("Changing password of %s\\%s (%s)\n",
204 session_info
->info
->domain_name
,
205 session_info
->info
->account_name
,
206 dom_sid_string(mem_ctx
, &session_info
->security_token
->sids
[PRIMARY_USER_SID_INDEX
])));
208 /* Performs the password change */
209 status
= samdb_set_password_sid(samdb
, mem_ctx
,
210 &session_info
->security_token
->sids
[PRIMARY_USER_SID_INDEX
],
211 password
, NULL
, NULL
,
212 oldLmHash
, oldNtHash
, /* this is a user password change */
215 return kpasswd_make_pwchange_reply(kdc
, mem_ctx
,
223 static bool kpasswd_process_request(struct kdc_server
*kdc
,
225 struct gensec_security
*gensec_security
,
230 struct auth_session_info
*session_info
;
233 if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security
,
236 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
237 KRB5_KPASSWD_HARDERROR
,
238 "gensec_session_info failed!",
243 case KRB5_KPASSWD_VERS_CHANGEPW
:
246 if (!convert_string_talloc_handle(mem_ctx
, lpcfg_iconv_handle(kdc
->task
->lp_ctx
),
248 (const char *)input
->data
,
250 (void **)&password
.data
, &pw_len
)) {
253 password
.length
= pw_len
;
255 return kpasswdd_change_password(kdc
, mem_ctx
, session_info
,
258 case KRB5_KPASSWD_VERS_SETPW
:
261 enum samPwdChangeReason reject_reason
= SAM_PWD_CHANGE_NO_ERROR
;
262 struct samr_DomInfo1
*dominfo
= NULL
;
263 struct ldb_context
*samdb
;
264 krb5_context context
= kdc
->smb_krb5_context
->krb5_context
;
266 ChangePasswdDataMS chpw
;
269 krb5_principal principal
;
270 char *set_password_on_princ
;
271 struct ldb_dn
*set_password_on_dn
;
272 bool service_principal_name
= false;
277 ret
= decode_ChangePasswdDataMS(input
->data
, input
->length
,
280 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
281 KRB5_KPASSWD_MALFORMED
,
282 "failed to decode password change structure",
286 if (!convert_string_talloc_handle(mem_ctx
, lpcfg_iconv_handle(kdc
->task
->lp_ctx
),
288 (const char *)chpw
.newpasswd
.data
,
289 chpw
.newpasswd
.length
,
290 (void **)&password
.data
, &pw_len
)) {
291 free_ChangePasswdDataMS(&chpw
);
295 password
.length
= pw_len
;
297 if ((chpw
.targname
&& !chpw
.targrealm
)
298 || (!chpw
.targname
&& chpw
.targrealm
)) {
299 free_ChangePasswdDataMS(&chpw
);
300 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
301 KRB5_KPASSWD_MALFORMED
,
302 "Realm and principal must be both present, or neither present",
305 if (chpw
.targname
&& chpw
.targrealm
) {
306 ret
= krb5_build_principal_ext(kdc
->smb_krb5_context
->krb5_context
,
308 strlen(*chpw
.targrealm
),
311 free_ChangePasswdDataMS(&chpw
);
312 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
313 KRB5_KPASSWD_MALFORMED
,
314 "failed to get principal",
317 if (copy_PrincipalName(chpw
.targname
, &principal
->name
)) {
318 free_ChangePasswdDataMS(&chpw
);
319 krb5_free_principal(context
, principal
);
320 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
321 KRB5_KPASSWD_MALFORMED
,
322 "failed to extract principal to set",
326 free_ChangePasswdDataMS(&chpw
);
327 return kpasswdd_change_password(kdc
, mem_ctx
, session_info
,
330 free_ChangePasswdDataMS(&chpw
);
332 if (principal
->name
.name_string
.len
>= 2) {
333 service_principal_name
= true;
335 /* We use this, rather than 'no realm' flag,
336 * as we don't want to accept a password
337 * change on a principal from another realm */
339 if (krb5_unparse_name_short(context
, principal
, &set_password_on_princ
) != 0) {
340 krb5_free_principal(context
, principal
);
341 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
342 KRB5_KPASSWD_MALFORMED
,
343 "krb5_unparse_name failed!",
347 if (krb5_unparse_name(context
, principal
, &set_password_on_princ
) != 0) {
348 krb5_free_principal(context
, principal
);
349 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
350 KRB5_KPASSWD_MALFORMED
,
351 "krb5_unparse_name failed!",
355 krb5_free_principal(context
, principal
);
357 samdb
= samdb_connect(mem_ctx
, kdc
->task
->event_ctx
, kdc
->task
->lp_ctx
, session_info
, 0);
359 free(set_password_on_princ
);
360 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
361 KRB5_KPASSWD_HARDERROR
,
362 "Unable to open database!",
366 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
367 session_info
->info
->domain_name
,
368 session_info
->info
->account_name
,
369 dom_sid_string(mem_ctx
, &session_info
->security_token
->sids
[PRIMARY_USER_SID_INDEX
]),
370 set_password_on_princ
));
371 ret
= ldb_transaction_start(samdb
);
372 if (ret
!= LDB_SUCCESS
) {
373 free(set_password_on_princ
);
374 status
= NT_STATUS_TRANSACTION_ABORTED
;
375 return kpasswd_make_pwchange_reply(kdc
, mem_ctx
,
377 SAM_PWD_CHANGE_NO_ERROR
,
382 if (service_principal_name
) {
383 status
= crack_service_principal_name(samdb
, mem_ctx
,
384 set_password_on_princ
,
385 &set_password_on_dn
, NULL
);
387 status
= crack_user_principal_name(samdb
, mem_ctx
,
388 set_password_on_princ
,
389 &set_password_on_dn
, NULL
);
391 free(set_password_on_princ
);
392 if (!NT_STATUS_IS_OK(status
)) {
393 ldb_transaction_cancel(samdb
);
394 return kpasswd_make_pwchange_reply(kdc
, mem_ctx
,
396 SAM_PWD_CHANGE_NO_ERROR
,
401 if (NT_STATUS_IS_OK(status
)) {
402 /* Admin password set */
403 status
= samdb_set_password(samdb
, mem_ctx
,
404 set_password_on_dn
, NULL
,
405 &password
, NULL
, NULL
,
406 NULL
, NULL
, /* this is not a user password change */
407 &reject_reason
, &dominfo
);
410 if (NT_STATUS_IS_OK(status
)) {
411 ret
= ldb_transaction_commit(samdb
);
412 if (ret
!= LDB_SUCCESS
) {
413 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
414 ldb_dn_get_linearized(set_password_on_dn
),
415 ldb_errstring(samdb
)));
416 status
= NT_STATUS_TRANSACTION_ABORTED
;
419 ldb_transaction_cancel(samdb
);
421 return kpasswd_make_pwchange_reply(kdc
, mem_ctx
,
428 return kpasswdd_make_error_reply(kdc
, mem_ctx
,
429 KRB5_KPASSWD_BAD_VERSION
,
430 talloc_asprintf(mem_ctx
,
431 "Protocol version %u not supported",
437 enum kdc_process_ret
kpasswdd_process(struct kdc_server
*kdc
,
441 struct tsocket_address
*peer_addr
,
442 struct tsocket_address
*my_addr
,
446 const uint16_t header_len
= 6;
449 uint16_t krb_priv_len
;
452 DATA_BLOB ap_req
, krb_priv_req
;
453 DATA_BLOB krb_priv_rep
= data_blob(NULL
, 0);
454 DATA_BLOB ap_rep
= data_blob(NULL
, 0);
455 DATA_BLOB kpasswd_req
, kpasswd_rep
;
456 struct cli_credentials
*server_credentials
;
457 struct gensec_security
*gensec_security
;
458 TALLOC_CTX
*tmp_ctx
= talloc_new(mem_ctx
);
463 return KDC_PROCESS_FAILED
;
467 talloc_free(tmp_ctx
);
468 return KDC_PROCESS_PROXY
;
471 /* Be parinoid. We need to ensure we don't just let the
472 * caller lead us into a buffer overflow */
473 if (input
->length
<= header_len
) {
474 talloc_free(tmp_ctx
);
475 return KDC_PROCESS_FAILED
;
478 len
= RSVAL(input
->data
, 0);
479 if (input
->length
!= len
) {
480 talloc_free(tmp_ctx
);
481 return KDC_PROCESS_FAILED
;
484 /* There are two different versions of this protocol so far,
485 * plus others in the standards pipe. Fortunetly they all
486 * take a very similar framing */
487 version
= RSVAL(input
->data
, 2);
488 ap_req_len
= RSVAL(input
->data
, 4);
489 if ((ap_req_len
>= len
) || (ap_req_len
+ header_len
) >= len
) {
490 talloc_free(tmp_ctx
);
491 return KDC_PROCESS_FAILED
;
494 krb_priv_len
= len
- ap_req_len
;
495 ap_req
= data_blob_const(&input
->data
[header_len
], ap_req_len
);
496 krb_priv_req
= data_blob_const(&input
->data
[header_len
+ ap_req_len
], krb_priv_len
);
498 server_credentials
= cli_credentials_init(tmp_ctx
);
499 if (!server_credentials
) {
500 DEBUG(1, ("Failed to init server credentials\n"));
501 talloc_free(tmp_ctx
);
502 return KDC_PROCESS_FAILED
;
505 /* We want the credentials subsystem to use the krb5 context
506 * we already have, rather than a new context */
507 cli_credentials_set_krb5_context(server_credentials
, kdc
->smb_krb5_context
);
508 cli_credentials_set_conf(server_credentials
, kdc
->task
->lp_ctx
);
510 keytab_name
= talloc_asprintf(server_credentials
, "HDB:samba4&%p", kdc
->base_ctx
);
512 cli_credentials_set_username(server_credentials
, "kadmin/changepw", CRED_SPECIFIED
);
513 ret
= cli_credentials_set_keytab_name(server_credentials
, kdc
->task
->lp_ctx
, keytab_name
, CRED_SPECIFIED
);
515 ret
= kpasswdd_make_unauth_error_reply(kdc
, mem_ctx
,
516 KRB5_KPASSWD_HARDERROR
,
517 talloc_asprintf(mem_ctx
,
518 "Failed to obtain server credentials for kadmin/changepw!"),
524 talloc_free(tmp_ctx
);
528 /* We don't strictly need to call this wrapper, and could call
529 * gensec_server_start directly, as we have no need for NTLM
530 * and we have a PAC, but this ensures that the wrapper can be
531 * safely extended for other helpful things in future */
532 nt_status
= samba_server_gensec_start(tmp_ctx
, kdc
->task
->event_ctx
,
538 if (!NT_STATUS_IS_OK(nt_status
)) {
539 talloc_free(tmp_ctx
);
540 return KDC_PROCESS_FAILED
;
543 /* The kerberos PRIV packets include these addresses. MIT
544 * clients check that they are present */
546 /* Skip this part for now, it breaks with a NetAPP filer and
547 * in any case where the client address is behind NAT. If
548 * older MIT clients need this, we might have to insert more
551 nt_status
= gensec_set_local_address(gensec_security
, peer_addr
);
552 if (!NT_STATUS_IS_OK(nt_status
)) {
553 talloc_free(tmp_ctx
);
554 return KDC_PROCESS_FAILED
;
558 nt_status
= gensec_set_local_address(gensec_security
, my_addr
);
559 if (!NT_STATUS_IS_OK(nt_status
)) {
560 talloc_free(tmp_ctx
);
561 return KDC_PROCESS_FAILED
;
564 /* We want the GENSEC wrap calls to generate PRIV tokens */
565 gensec_want_feature(gensec_security
, GENSEC_FEATURE_SEAL
);
567 nt_status
= gensec_start_mech_by_name(gensec_security
, "krb5");
568 if (!NT_STATUS_IS_OK(nt_status
)) {
569 talloc_free(tmp_ctx
);
570 return KDC_PROCESS_FAILED
;
573 /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
574 nt_status
= gensec_update_ev(gensec_security
, tmp_ctx
, kdc
->task
->event_ctx
, ap_req
, &ap_rep
);
575 if (!NT_STATUS_IS_OK(nt_status
) && !NT_STATUS_EQUAL(nt_status
, NT_STATUS_MORE_PROCESSING_REQUIRED
)) {
577 ret
= kpasswdd_make_unauth_error_reply(kdc
, mem_ctx
,
578 KRB5_KPASSWD_HARDERROR
,
579 talloc_asprintf(mem_ctx
,
580 "gensec_update failed: %s",
581 nt_errstr(nt_status
)),
587 talloc_free(tmp_ctx
);
588 return KDC_PROCESS_FAILED
;
591 /* Extract the data from the KRB-PRIV half of the message */
592 nt_status
= gensec_unwrap(gensec_security
, tmp_ctx
, &krb_priv_req
, &kpasswd_req
);
593 if (!NT_STATUS_IS_OK(nt_status
)) {
594 ret
= kpasswdd_make_unauth_error_reply(kdc
, mem_ctx
,
595 KRB5_KPASSWD_HARDERROR
,
596 talloc_asprintf(mem_ctx
,
597 "gensec_unwrap failed: %s",
598 nt_errstr(nt_status
)),
604 talloc_free(tmp_ctx
);
605 return KDC_PROCESS_FAILED
;
608 /* Figure out something to do with it (probably changing a password...) */
609 ret
= kpasswd_process_request(kdc
, tmp_ctx
,
612 &kpasswd_req
, &kpasswd_rep
);
615 talloc_free(tmp_ctx
);
616 return KDC_PROCESS_FAILED
;
619 /* And wrap up the reply: This ensures that the error message
620 * or success can be verified by the client */
621 nt_status
= gensec_wrap(gensec_security
, tmp_ctx
,
622 &kpasswd_rep
, &krb_priv_rep
);
623 if (!NT_STATUS_IS_OK(nt_status
)) {
624 ret
= kpasswdd_make_unauth_error_reply(kdc
, mem_ctx
,
625 KRB5_KPASSWD_HARDERROR
,
626 talloc_asprintf(mem_ctx
,
627 "gensec_wrap failed: %s",
628 nt_errstr(nt_status
)),
634 talloc_free(tmp_ctx
);
635 return KDC_PROCESS_FAILED
;
639 *reply
= data_blob_talloc(mem_ctx
, NULL
, krb_priv_rep
.length
+ ap_rep
.length
+ header_len
);
641 talloc_free(tmp_ctx
);
642 return KDC_PROCESS_FAILED
;
645 RSSVAL(reply
->data
, 0, reply
->length
);
646 RSSVAL(reply
->data
, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
647 RSSVAL(reply
->data
, 4, ap_rep
.length
);
648 memcpy(reply
->data
+ header_len
,
651 memcpy(reply
->data
+ header_len
+ ap_rep
.length
,
653 krb_priv_rep
.length
);
655 talloc_free(tmp_ctx
);
656 return KDC_PROCESS_OK
;