735cafa5249115e241745bd8434fee384a81141a
[tprouty/samba.git] / source / libads / krb5_setpw.c
1 /* 
2    Unix SMB/CIFS implementation.
3    krb5 set password implementation
4    Copyright (C) Andrew Tridgell 2001
5    Copyright (C) Remus Koos 2001 (remuskoos@yahoo.com)
6    
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 3 of the License, or
10    (at your option) any later version.
11    
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16    
17    You should have received a copy of the GNU General Public License
18    along with this program; if not, write to the Free Software
19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22 #include "includes.h"
23
24 #ifdef HAVE_KRB5
25
26 #define DEFAULT_KPASSWD_PORT    464
27
28 #define KRB5_KPASSWD_VERS_CHANGEPW              1
29
30 #define KRB5_KPASSWD_VERS_SETPW                 0xff80
31 #define KRB5_KPASSWD_VERS_SETPW_ALT             2
32
33 #define KRB5_KPASSWD_SUCCESS                    0
34 #define KRB5_KPASSWD_MALFORMED                  1
35 #define KRB5_KPASSWD_HARDERROR                  2
36 #define KRB5_KPASSWD_AUTHERROR                  3
37 #define KRB5_KPASSWD_SOFTERROR                  4
38 #define KRB5_KPASSWD_ACCESSDENIED               5
39 #define KRB5_KPASSWD_BAD_VERSION                6
40 #define KRB5_KPASSWD_INITIAL_FLAG_NEEDED        7
41
42 /* Those are defined by kerberos-set-passwd-02.txt and are probably 
43  * not supported by M$ implementation */
44 #define KRB5_KPASSWD_POLICY_REJECT              8
45 #define KRB5_KPASSWD_BAD_PRINCIPAL              9
46 #define KRB5_KPASSWD_ETYPE_NOSUPP               10
47
48 /*
49  * we've got to be able to distinguish KRB_ERRORs from other
50  * requests - valid response for CHPW v2 replies.
51  */
52
53 #define krb5_is_krb_error(packet) \
54         ( packet && packet->length && (((char *)packet->data)[0] == 0x7e || ((char *)packet->data)[0] == 0x5e))
55
56 /* This implements kerberos password change protocol as specified in 
57  * kerb-chg-password-02.txt and kerberos-set-passwd-02.txt
58  * as well as microsoft version of the protocol 
59  * as specified in kerberos-set-passwd-00.txt
60  */
61 static DATA_BLOB encode_krb5_setpw(const char *principal, const char *password)
62 {
63         char* princ_part1 = NULL;
64         char* princ_part2 = NULL;
65         char* realm = NULL;
66         char* c;
67         char* princ;
68
69         ASN1_DATA req;
70         DATA_BLOB ret;
71
72
73         princ = SMB_STRDUP(principal);
74
75         if ((c = strchr_m(princ, '/')) == NULL) {
76                 c = princ; 
77         } else {
78                 *c = '\0';
79                 c++;
80                 princ_part1 = princ;
81         }
82
83         princ_part2 = c;
84
85         if ((c = strchr_m(c, '@')) != NULL) {
86                 *c = '\0';
87                 c++;
88                 realm = c;
89         } else {
90                 /* We must have a realm component. */
91                 return data_blob_null;
92         }
93
94         memset(&req, 0, sizeof(req));
95         
96         asn1_push_tag(&req, ASN1_SEQUENCE(0));
97         asn1_push_tag(&req, ASN1_CONTEXT(0));
98         asn1_write_OctetString(&req, password, strlen(password));
99         asn1_pop_tag(&req);
100
101         asn1_push_tag(&req, ASN1_CONTEXT(1));
102         asn1_push_tag(&req, ASN1_SEQUENCE(0));
103
104         asn1_push_tag(&req, ASN1_CONTEXT(0));
105         asn1_write_Integer(&req, 1);
106         asn1_pop_tag(&req);
107
108         asn1_push_tag(&req, ASN1_CONTEXT(1));
109         asn1_push_tag(&req, ASN1_SEQUENCE(0));
110
111         if (princ_part1) {
112                 asn1_write_GeneralString(&req, princ_part1);
113         }
114         
115         asn1_write_GeneralString(&req, princ_part2);
116         asn1_pop_tag(&req);
117         asn1_pop_tag(&req);
118         asn1_pop_tag(&req);
119         asn1_pop_tag(&req);
120
121         asn1_push_tag(&req, ASN1_CONTEXT(2));
122         asn1_write_GeneralString(&req, realm);
123         asn1_pop_tag(&req);
124         asn1_pop_tag(&req);
125
126         ret = data_blob(req.data, req.length);
127         asn1_free(&req);
128
129         free(princ);
130
131         return ret;
132 }       
133
134 static krb5_error_code build_kpasswd_request(uint16 pversion,
135                                            krb5_context context,
136                                            krb5_auth_context auth_context,
137                                            krb5_data *ap_req,
138                                            const char *princ,
139                                            const char *passwd,
140                                            BOOL use_tcp,
141                                            krb5_data *packet)
142 {
143         krb5_error_code ret;
144         krb5_data cipherpw;
145         krb5_data encoded_setpw;
146         krb5_replay_data replay;
147         char *p, *msg_start;
148         DATA_BLOB setpw;
149         unsigned int msg_length;
150
151         ret = krb5_auth_con_setflags(context,
152                                      auth_context,KRB5_AUTH_CONTEXT_DO_SEQUENCE);
153         if (ret) {
154                 DEBUG(1,("krb5_auth_con_setflags failed (%s)\n",
155                          error_message(ret)));
156                 return ret;
157         }
158
159         /* handle protocol differences in chpw and setpw */
160         if (pversion  == KRB5_KPASSWD_VERS_CHANGEPW)
161                 setpw = data_blob(passwd, strlen(passwd));
162         else if (pversion == KRB5_KPASSWD_VERS_SETPW ||
163                  pversion == KRB5_KPASSWD_VERS_SETPW_ALT)
164                 setpw = encode_krb5_setpw(princ, passwd);
165         else
166                 return EINVAL;
167
168         if (setpw.data == NULL || setpw.length == 0) {
169                 return EINVAL;
170         }
171
172         encoded_setpw.data = (char *)setpw.data;
173         encoded_setpw.length = setpw.length;
174
175         ret = krb5_mk_priv(context, auth_context,
176                            &encoded_setpw, &cipherpw, &replay);
177         
178         data_blob_free(&setpw);         /*from 'encode_krb5_setpw(...)' */
179         
180         if (ret) {
181                 DEBUG(1,("krb5_mk_priv failed (%s)\n", error_message(ret)));
182                 return ret;
183         }
184
185         packet->data = (char *)SMB_MALLOC(ap_req->length + cipherpw.length + (use_tcp ? 10 : 6 ));
186         if (!packet->data)
187                 return -1;
188
189
190
191         /* see the RFC for details */
192
193         msg_start = p = ((char *)packet->data) + (use_tcp ? 4 : 0);
194         p += 2;
195         RSSVAL(p, 0, pversion);
196         p += 2;
197         RSSVAL(p, 0, ap_req->length);
198         p += 2;
199         memcpy(p, ap_req->data, ap_req->length);
200         p += ap_req->length;
201         memcpy(p, cipherpw.data, cipherpw.length);
202         p += cipherpw.length;
203         packet->length = PTR_DIFF(p,packet->data);
204         msg_length = PTR_DIFF(p,msg_start);
205
206         if (use_tcp) {
207                 RSIVAL(packet->data, 0, msg_length);
208         }
209         RSSVAL(msg_start, 0, msg_length);
210         
211         free(cipherpw.data);    /* from 'krb5_mk_priv(...)' */
212
213         return 0;
214 }
215
216 static const struct kpasswd_errors {
217         int result_code;
218         const char *error_string;
219 } kpasswd_errors[] = {
220         {KRB5_KPASSWD_MALFORMED, "Malformed request error"},
221         {KRB5_KPASSWD_HARDERROR, "Server error"},
222         {KRB5_KPASSWD_AUTHERROR, "Authentication error"},
223         {KRB5_KPASSWD_SOFTERROR, "Password change rejected"},
224         {KRB5_KPASSWD_ACCESSDENIED, "Client does not have proper authorization"},
225         {KRB5_KPASSWD_BAD_VERSION, "Protocol version not supported"},
226         {KRB5_KPASSWD_INITIAL_FLAG_NEEDED, "Authorization ticket must have initial flag set"},
227         {KRB5_KPASSWD_POLICY_REJECT, "Password rejected due to policy requirements"},
228         {KRB5_KPASSWD_BAD_PRINCIPAL, "Target principal does not exist"},
229         {KRB5_KPASSWD_ETYPE_NOSUPP, "Unsupported encryption type"},
230         {0, NULL}
231 };
232
233 static krb5_error_code setpw_result_code_string(krb5_context context,
234                                                 int result_code,
235                                                 const char **code_string)
236 {
237         unsigned int idx = 0;
238
239         while (kpasswd_errors[idx].error_string != NULL) {
240                 if (kpasswd_errors[idx].result_code == 
241                     result_code) {
242                         *code_string = kpasswd_errors[idx].error_string;
243                         return 0;
244                 }
245                 idx++;
246         }
247         *code_string = "Password change failed";
248         return (0);
249 }
250
251  krb5_error_code kpasswd_err_to_krb5_err(krb5_error_code res_code) 
252 {
253         switch(res_code) {
254                 case KRB5_KPASSWD_ACCESSDENIED:
255                         return KRB5KDC_ERR_BADOPTION;
256                 case KRB5_KPASSWD_INITIAL_FLAG_NEEDED:
257                         return KRB5KDC_ERR_BADOPTION;
258                         /* return KV5M_ALT_METHOD; MIT-only define */
259                 case KRB5_KPASSWD_ETYPE_NOSUPP:
260                         return KRB5KDC_ERR_ETYPE_NOSUPP;
261                 case KRB5_KPASSWD_BAD_PRINCIPAL:
262                         return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
263                 case KRB5_KPASSWD_POLICY_REJECT:
264                 case KRB5_KPASSWD_SOFTERROR:
265                         return KRB5KDC_ERR_POLICY;
266                 default:
267                         return KRB5KRB_ERR_GENERIC;
268         }
269 }
270 static krb5_error_code parse_setpw_reply(krb5_context context,
271                                          BOOL use_tcp,
272                                          krb5_auth_context auth_context,
273                                          krb5_data *packet)
274 {
275         krb5_data ap_rep;
276         char *p;
277         int vnum, ret, res_code;
278         krb5_data cipherresult;
279         krb5_data clearresult;
280         krb5_ap_rep_enc_part *ap_rep_enc;
281         krb5_replay_data replay;
282         unsigned int msg_length = packet->length;
283
284
285         if (packet->length < (use_tcp ? 8 : 4)) {
286                 return KRB5KRB_AP_ERR_MODIFIED;
287         }
288         
289         p = packet->data;
290         /*
291         ** see if it is an error
292         */
293         if (krb5_is_krb_error(packet)) {
294
295                 ret = handle_krberror_packet(context, packet);
296                 if (ret) {
297                         return ret;
298                 }
299         }
300
301         
302         /* tcp... */
303         if (use_tcp) {
304                 msg_length -= 4;
305                 if (RIVAL(p, 0) != msg_length) {
306                         DEBUG(1,("Bad TCP packet length (%d/%d) from kpasswd server\n",
307                         RIVAL(p, 0), msg_length));
308                         return KRB5KRB_AP_ERR_MODIFIED;
309                 }
310
311                 p += 4;
312         }
313         
314         if (RSVAL(p, 0) != msg_length) {
315                 DEBUG(1,("Bad packet length (%d/%d) from kpasswd server\n",
316                          RSVAL(p, 0), msg_length));
317                 return KRB5KRB_AP_ERR_MODIFIED;
318         }
319
320         p += 2;
321
322         vnum = RSVAL(p, 0); p += 2;
323
324         /* FIXME: According to standard there is only one type of reply */      
325         if (vnum != KRB5_KPASSWD_VERS_SETPW && 
326             vnum != KRB5_KPASSWD_VERS_SETPW_ALT && 
327             vnum != KRB5_KPASSWD_VERS_CHANGEPW) {
328                 DEBUG(1,("Bad vnum (%d) from kpasswd server\n", vnum));
329                 return KRB5KDC_ERR_BAD_PVNO;
330         }
331         
332         ap_rep.length = RSVAL(p, 0); p += 2;
333         
334         if (p + ap_rep.length >= (char *)packet->data + packet->length) {
335                 DEBUG(1,("ptr beyond end of packet from kpasswd server\n"));
336                 return KRB5KRB_AP_ERR_MODIFIED;
337         }
338         
339         if (ap_rep.length == 0) {
340                 DEBUG(1,("got unencrypted setpw result?!\n"));
341                 return KRB5KRB_AP_ERR_MODIFIED;
342         }
343
344         /* verify ap_rep */
345         ap_rep.data = p;
346         p += ap_rep.length;
347         
348         ret = krb5_rd_rep(context, auth_context, &ap_rep, &ap_rep_enc);
349         if (ret) {
350                 DEBUG(1,("failed to rd setpw reply (%s)\n", error_message(ret)));
351                 return KRB5KRB_AP_ERR_MODIFIED;
352         }
353         
354         krb5_free_ap_rep_enc_part(context, ap_rep_enc);
355         
356         cipherresult.data = p;
357         cipherresult.length = ((char *)packet->data + packet->length) - p;
358                 
359         ret = krb5_rd_priv(context, auth_context, &cipherresult, &clearresult,
360                            &replay);
361         if (ret) {
362                 DEBUG(1,("failed to decrypt setpw reply (%s)\n", error_message(ret)));
363                 return KRB5KRB_AP_ERR_MODIFIED;
364         }
365
366         if (clearresult.length < 2) {
367                 free(clearresult.data);
368                 ret = KRB5KRB_AP_ERR_MODIFIED;
369                 return KRB5KRB_AP_ERR_MODIFIED;
370         }
371         
372         p = clearresult.data;
373         
374         res_code = RSVAL(p, 0);
375         
376         free(clearresult.data);
377
378         if ((res_code < KRB5_KPASSWD_SUCCESS) || 
379             (res_code > KRB5_KPASSWD_ETYPE_NOSUPP)) {
380                 return KRB5KRB_AP_ERR_MODIFIED;
381         }
382
383         if (res_code == KRB5_KPASSWD_SUCCESS) {
384                 return 0;
385         } else {
386                 const char *errstr;
387                 setpw_result_code_string(context, res_code, &errstr);
388                 DEBUG(1, ("Error changing password: %s (%d)\n", errstr, res_code));
389
390                 return kpasswd_err_to_krb5_err(res_code);
391         }
392 }
393
394 static ADS_STATUS do_krb5_kpasswd_request(krb5_context context,
395                                           const char *kdc_host,
396                                           uint16 pversion,
397                                           krb5_creds *credsp,
398                                           const char *princ,
399                                           const char *newpw)
400 {
401         krb5_auth_context auth_context = NULL;
402         krb5_data ap_req, chpw_req, chpw_rep;
403         int ret, sock;
404         socklen_t addr_len;
405         struct sockaddr remote_addr, local_addr;
406         struct in_addr *addr = interpret_addr2(kdc_host);
407         krb5_address local_kaddr, remote_kaddr;
408         BOOL    use_tcp = False;
409
410
411         ret = krb5_mk_req_extended(context, &auth_context, AP_OPTS_USE_SUBKEY,
412                                    NULL, credsp, &ap_req);
413         if (ret) {
414                 DEBUG(1,("krb5_mk_req_extended failed (%s)\n", error_message(ret)));
415                 return ADS_ERROR_KRB5(ret);
416         }
417
418         do {
419
420                 if (!use_tcp) {
421
422                         sock = open_udp_socket(kdc_host, DEFAULT_KPASSWD_PORT);
423
424                 } else {
425
426                         sock = open_socket_out(SOCK_STREAM, addr, DEFAULT_KPASSWD_PORT, 
427                                                LONG_CONNECT_TIMEOUT);
428                 }
429
430                 if (sock == -1) {
431                         int rc = errno;
432                         SAFE_FREE(ap_req.data);
433                         krb5_auth_con_free(context, auth_context);
434                         DEBUG(1,("failed to open kpasswd socket to %s (%s)\n", 
435                                  kdc_host, strerror(errno)));
436                         return ADS_ERROR_SYSTEM(rc);
437                 }
438                 
439                 addr_len = sizeof(remote_addr);
440                 getpeername(sock, &remote_addr, &addr_len);
441                 addr_len = sizeof(local_addr);
442                 getsockname(sock, &local_addr, &addr_len);
443                 
444                 setup_kaddr(&remote_kaddr, &remote_addr);
445                 setup_kaddr(&local_kaddr, &local_addr);
446         
447                 ret = krb5_auth_con_setaddrs(context, auth_context, &local_kaddr, NULL);
448                 if (ret) {
449                         close(sock);
450                         SAFE_FREE(ap_req.data);
451                         krb5_auth_con_free(context, auth_context);
452                         DEBUG(1,("krb5_auth_con_setaddrs failed (%s)\n", error_message(ret)));
453                         return ADS_ERROR_KRB5(ret);
454                 }
455         
456                 ret = build_kpasswd_request(pversion, context, auth_context, &ap_req,
457                                           princ, newpw, use_tcp, &chpw_req);
458                 if (ret) {
459                         close(sock);
460                         SAFE_FREE(ap_req.data);
461                         krb5_auth_con_free(context, auth_context);
462                         DEBUG(1,("build_setpw_request failed (%s)\n", error_message(ret)));
463                         return ADS_ERROR_KRB5(ret);
464                 }
465
466                 ret = write(sock, chpw_req.data, chpw_req.length); 
467
468                 if (ret != chpw_req.length) {
469                         close(sock);
470                         SAFE_FREE(chpw_req.data);
471                         SAFE_FREE(ap_req.data);
472                         krb5_auth_con_free(context, auth_context);
473                         DEBUG(1,("send of chpw failed (%s)\n", strerror(errno)));
474                         return ADS_ERROR_SYSTEM(errno);
475                 }
476         
477                 SAFE_FREE(chpw_req.data);
478         
479                 chpw_rep.length = 1500;
480                 chpw_rep.data = (char *) SMB_MALLOC(chpw_rep.length);
481                 if (!chpw_rep.data) {
482                         close(sock);
483                         SAFE_FREE(ap_req.data);
484                         krb5_auth_con_free(context, auth_context);
485                         DEBUG(1,("send of chpw failed (%s)\n", strerror(errno)));
486                         errno = ENOMEM;
487                         return ADS_ERROR_SYSTEM(errno);
488                 }
489         
490                 ret = read(sock, chpw_rep.data, chpw_rep.length);
491                 if (ret < 0) {
492                         close(sock);
493                         SAFE_FREE(chpw_rep.data);
494                         SAFE_FREE(ap_req.data);
495                         krb5_auth_con_free(context, auth_context);
496                         DEBUG(1,("recv of chpw reply failed (%s)\n", strerror(errno)));
497                         return ADS_ERROR_SYSTEM(errno);
498                 }
499         
500                 close(sock);
501                 chpw_rep.length = ret;
502         
503                 ret = krb5_auth_con_setaddrs(context, auth_context, NULL,&remote_kaddr);
504                 if (ret) {
505                         SAFE_FREE(chpw_rep.data);
506                         SAFE_FREE(ap_req.data);
507                         krb5_auth_con_free(context, auth_context);
508                         DEBUG(1,("krb5_auth_con_setaddrs on reply failed (%s)\n", 
509                                  error_message(ret)));
510                         return ADS_ERROR_KRB5(ret);
511                 }
512         
513                 ret = parse_setpw_reply(context, use_tcp, auth_context, &chpw_rep);
514                 SAFE_FREE(chpw_rep.data);
515         
516                 if (ret) {
517                         
518                         if (ret == KRB5KRB_ERR_RESPONSE_TOO_BIG && !use_tcp) {
519                                 DEBUG(5, ("Trying setpw with TCP!!!\n"));
520                                 use_tcp = True;
521                                 continue;
522                         }
523
524                         SAFE_FREE(ap_req.data);
525                         krb5_auth_con_free(context, auth_context);
526                         DEBUG(1,("parse_setpw_reply failed (%s)\n", 
527                                  error_message(ret)));
528                         return ADS_ERROR_KRB5(ret);
529                 }
530         
531                 SAFE_FREE(ap_req.data);
532                 krb5_auth_con_free(context, auth_context);
533         } while ( ret );
534
535         return ADS_SUCCESS;
536 }
537
538 ADS_STATUS ads_krb5_set_password(const char *kdc_host, const char *princ, 
539                                  const char *newpw, int time_offset)
540 {
541
542         ADS_STATUS aret;
543         krb5_error_code ret = 0;
544         krb5_context context = NULL;
545         krb5_principal principal = NULL;
546         char *princ_name = NULL;
547         char *realm = NULL;
548         krb5_creds creds, *credsp = NULL;
549 #if KRB5_PRINC_REALM_RETURNS_REALM
550         krb5_realm orig_realm;
551 #else
552         krb5_data orig_realm;
553 #endif
554         krb5_ccache ccache = NULL;
555
556         ZERO_STRUCT(creds);
557         
558         initialize_krb5_error_table();
559         ret = krb5_init_context(&context);
560         if (ret) {
561                 DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret)));
562                 return ADS_ERROR_KRB5(ret);
563         }
564         
565         if (time_offset != 0) {
566                 krb5_set_real_time(context, time(NULL) + time_offset, 0);
567         }
568
569         ret = krb5_cc_default(context, &ccache);
570         if (ret) {
571                 krb5_free_context(context);
572                 DEBUG(1,("Failed to get default creds (%s)\n", error_message(ret)));
573                 return ADS_ERROR_KRB5(ret);
574         }
575
576         realm = strchr_m(princ, '@');
577         if (!realm) {
578                 krb5_cc_close(context, ccache);
579                 krb5_free_context(context);
580                 DEBUG(1,("Failed to get realm\n"));
581                 return ADS_ERROR_KRB5(-1);
582         }
583         realm++;
584
585         asprintf(&princ_name, "kadmin/changepw@%s", realm);
586         ret = smb_krb5_parse_name(context, princ_name, &creds.server);
587         if (ret) {
588                 krb5_cc_close(context, ccache);
589                 krb5_free_context(context);
590                 DEBUG(1,("Failed to parse kadmin/changepw (%s)\n", error_message(ret)));
591                 return ADS_ERROR_KRB5(ret);
592         }
593
594         /* parse the principal we got as a function argument */
595         ret = smb_krb5_parse_name(context, princ, &principal);
596         if (ret) {
597                 krb5_cc_close(context, ccache);
598                 krb5_free_principal(context, creds.server);
599                 krb5_free_context(context);
600                 DEBUG(1,("Failed to parse %s (%s)\n", princ_name, error_message(ret)));
601                 free(princ_name);
602                 return ADS_ERROR_KRB5(ret);
603         }
604
605         free(princ_name);
606
607         /* The creds.server principal takes ownership of this memory.
608                 Remember to set back to original value before freeing. */
609         orig_realm = *krb5_princ_realm(context, creds.server);
610         krb5_princ_set_realm(context, creds.server, krb5_princ_realm(context, principal));
611         
612         ret = krb5_cc_get_principal(context, ccache, &creds.client);
613         if (ret) {
614                 krb5_cc_close(context, ccache);
615                 krb5_princ_set_realm(context, creds.server, &orig_realm);
616                 krb5_free_principal(context, creds.server);
617                 krb5_free_principal(context, principal);
618                 krb5_free_context(context);
619                 DEBUG(1,("Failed to get principal from ccache (%s)\n", 
620                          error_message(ret)));
621                 return ADS_ERROR_KRB5(ret);
622         }
623         
624         ret = krb5_get_credentials(context, 0, ccache, &creds, &credsp); 
625         if (ret) {
626                 krb5_cc_close(context, ccache);
627                 krb5_free_principal(context, creds.client);
628                 krb5_princ_set_realm(context, creds.server, &orig_realm);
629                 krb5_free_principal(context, creds.server);
630                 krb5_free_principal(context, principal);
631                 krb5_free_context(context);
632                 DEBUG(1,("krb5_get_credentials failed (%s)\n", error_message(ret)));
633                 return ADS_ERROR_KRB5(ret);
634         }
635         
636         /* we might have to call krb5_free_creds(...) from now on ... */
637
638         aret = do_krb5_kpasswd_request(context, kdc_host,
639                                        KRB5_KPASSWD_VERS_SETPW,
640                                        credsp, princ, newpw);
641
642         krb5_free_creds(context, credsp);
643         krb5_free_principal(context, creds.client);
644         krb5_princ_set_realm(context, creds.server, &orig_realm);
645         krb5_free_principal(context, creds.server);
646         krb5_free_principal(context, principal);
647         krb5_cc_close(context, ccache);
648         krb5_free_context(context);
649
650         return aret;
651 }
652
653 /*
654   we use a prompter to avoid a crash bug in the kerberos libs when 
655   dealing with empty passwords
656   this prompter is just a string copy ...
657 */
658 static krb5_error_code 
659 kerb_prompter(krb5_context ctx, void *data,
660                const char *name,
661                const char *banner,
662                int num_prompts,
663                krb5_prompt prompts[])
664 {
665         if (num_prompts == 0) return 0;
666
667         memset(prompts[0].reply->data, 0, prompts[0].reply->length);
668         if (prompts[0].reply->length > 0) {
669                 if (data) {
670                         strncpy(prompts[0].reply->data,
671                                 (const char *)data,
672                                 prompts[0].reply->length-1);
673                         prompts[0].reply->length = strlen(prompts[0].reply->data);
674                 } else {
675                         prompts[0].reply->length = 0;
676                 }
677         }
678         return 0;
679 }
680
681 static ADS_STATUS ads_krb5_chg_password(const char *kdc_host,
682                                         const char *principal,
683                                         const char *oldpw, 
684                                         const char *newpw, 
685                                         int time_offset)
686 {
687     ADS_STATUS aret;
688     krb5_error_code ret;
689     krb5_context context = NULL;
690     krb5_principal princ;
691     krb5_get_init_creds_opt opts;
692     krb5_creds creds;
693     char *chpw_princ = NULL, *password;
694
695     initialize_krb5_error_table();
696     ret = krb5_init_context(&context);
697     if (ret) {
698         DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret)));
699         return ADS_ERROR_KRB5(ret);
700     }
701
702     if ((ret = smb_krb5_parse_name(context, principal,
703                                     &princ))) {
704         krb5_free_context(context);
705         DEBUG(1,("Failed to parse %s (%s)\n", principal, error_message(ret)));
706         return ADS_ERROR_KRB5(ret);
707     }
708
709     krb5_get_init_creds_opt_init(&opts);
710     krb5_get_init_creds_opt_set_tkt_life(&opts, 5*60);
711     krb5_get_init_creds_opt_set_renew_life(&opts, 0);
712     krb5_get_init_creds_opt_set_forwardable(&opts, 0);
713     krb5_get_init_creds_opt_set_proxiable(&opts, 0);
714
715     /* We have to obtain an INITIAL changepw ticket for changing password */
716     asprintf(&chpw_princ, "kadmin/changepw@%s",
717                                 (char *) krb5_princ_realm(context, princ));
718     password = SMB_STRDUP(oldpw);
719     ret = krb5_get_init_creds_password(context, &creds, princ, password,
720                                            kerb_prompter, NULL, 
721                                            0, chpw_princ, &opts);
722     SAFE_FREE(chpw_princ);
723     SAFE_FREE(password);
724
725     if (ret) {
726       if (ret == KRB5KRB_AP_ERR_BAD_INTEGRITY)
727         DEBUG(1,("Password incorrect while getting initial ticket"));
728       else
729         DEBUG(1,("krb5_get_init_creds_password failed (%s)\n", error_message(ret)));
730
731         krb5_free_principal(context, princ);
732         krb5_free_context(context);
733         return ADS_ERROR_KRB5(ret);
734     }
735
736     aret = do_krb5_kpasswd_request(context, kdc_host,
737                                    KRB5_KPASSWD_VERS_CHANGEPW,
738                                    &creds, principal, newpw);
739
740     krb5_free_principal(context, princ);
741     krb5_free_context(context);
742
743     return aret;
744 }
745
746
747 ADS_STATUS kerberos_set_password(const char *kpasswd_server, 
748                                  const char *auth_principal, const char *auth_password,
749                                  const char *target_principal, const char *new_password,
750                                  int time_offset)
751 {
752     int ret;
753
754     if ((ret = kerberos_kinit_password(auth_principal, auth_password, time_offset, NULL))) {
755         DEBUG(1,("Failed kinit for principal %s (%s)\n", auth_principal, error_message(ret)));
756         return ADS_ERROR_KRB5(ret);
757     }
758
759     if (!strcmp(auth_principal, target_principal))
760         return ads_krb5_chg_password(kpasswd_server, target_principal,
761                                      auth_password, new_password, time_offset);
762     else
763         return ads_krb5_set_password(kpasswd_server, target_principal,
764                                      new_password, time_offset);
765 }
766
767
768 /**
769  * Set the machine account password
770  * @param ads connection to ads server
771  * @param hostname machine whose password is being set
772  * @param password new password
773  * @return status of password change
774  **/
775 ADS_STATUS ads_set_machine_password(ADS_STRUCT *ads,
776                                     const char *machine_account,
777                                     const char *password)
778 {
779         ADS_STATUS status;
780         char *principal = NULL; 
781
782         /*
783           we need to use the '$' form of the name here (the machine account name), 
784           as otherwise the server might end up setting the password for a user
785           instead
786          */
787         asprintf(&principal, "%s@%s", machine_account, ads->config.realm);
788         
789         status = ads_krb5_set_password(ads->auth.kdc_server, principal, 
790                                        password, ads->auth.time_offset);
791         
792         free(principal);
793
794         return status;
795 }
796
797
798
799 #endif