r1243: Fix so this compiles with Heimdal (in Heimdal krb5_kt_cursor is a struct not...
[samba.git] / source3 / libads / kerberos_keytab.c
1 /*
2    Unix SMB/CIFS implementation.
3    kerberos keytab utility library
4    Copyright (C) Andrew Tridgell 2001
5    Copyright (C) Remus Koos 2001
6    Copyright (C) Luke Howard 2003
7    Copyright (C) Jim McDonough (jmcd@us.ibm.com) 2003
8    Copyright (C) Guenther Deschner 2003
9    Copyright (C) Rakesh Patel 2004
10    Copyright (C) Dan Perry 2004
11    Copyright (C) Jeremy Allison 2004
12
13    This program is free software; you can redistribute it and/or modify
14    it under the terms of the GNU General Public License as published by
15    the Free Software Foundation; either version 2 of the License, or
16    (at your option) any later version.
17
18    This program is distributed in the hope that it will be useful,
19    but WITHOUT ANY WARRANTY; without even the implied warranty of
20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21    GNU General Public License for more details.
22
23    You should have received a copy of the GNU General Public License
24    along with this program; if not, write to the Free Software
25    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 */
27
28 #include "includes.h"
29
30 #ifdef HAVE_KRB5
31
32 /**********************************************************************
33  Adds a single service principal, i.e. 'host' to the system keytab
34 ***********************************************************************/
35
36 int ads_keytab_add_entry(ADS_STRUCT *ads, const char *srvPrinc)
37 {
38         krb5_error_code ret = 0;
39         krb5_context context = NULL;
40         krb5_keytab keytab = NULL;
41         krb5_kt_cursor cursor;
42         krb5_keytab_entry kt_entry;
43         krb5_principal princ = NULL;
44         krb5_data password;
45         krb5_enctype *enctypes = NULL;
46         krb5_kvno kvno;
47
48         char *principal = NULL;
49         char *princ_s = NULL;
50         char *password_s = NULL;
51 #ifndef MAX_KEYTAB_NAME_LEN
52 #define MAX_KEYTAB_NAME_LEN 1100
53 #endif
54         char keytab_name[MAX_KEYTAB_NAME_LEN];          /* This MAX_NAME_LEN is a constant defined in krb5.h */
55         fstring my_fqdn;
56         int i;
57         char *ktprinc = NULL;
58
59         ZERO_STRUCT(kt_entry);
60         ZERO_STRUCT(cursor);
61
62         initialize_krb5_error_table();
63         ret = krb5_init_context(&context);
64         if (ret) {
65                 DEBUG(1,("ads_keytab_add_entry: could not krb5_init_context: %s\n",error_message(ret)));
66                 return -1;
67         }
68 #ifdef HAVE_WRFILE_KEYTAB       /* MIT */
69         keytab_name[0] = 'W';
70         keytab_name[1] = 'R';
71         ret = krb5_kt_default_name(context, (char *) &keytab_name[2], MAX_KEYTAB_NAME_LEN - 4);
72 #else                           /* Heimdal */
73         ret = krb5_kt_default_name(context, (char *) &keytab_name[0], MAX_KEYTAB_NAME_LEN - 2);
74 #endif
75         if (ret) {
76                 DEBUG(1,("ads_keytab_add_entry: krb5_kt_default_name failed (%s)\n", error_message(ret)));
77                 goto out;
78         }
79         DEBUG(2,("ads_keytab_add_entry: Using default system keytab: %s\n", (char *) &keytab_name));
80         ret = krb5_kt_resolve(context, (char *) &keytab_name, &keytab);
81         if (ret) {
82                 DEBUG(1,("ads_keytab_add_entry: krb5_kt_resolve failed (%s)\n", error_message(ret)));
83                 goto out;
84         }
85
86         /* retrieve the password */
87         if (!secrets_init()) {
88                 DEBUG(1,("ads_keytab_add_entry: secrets_init failed\n"));
89                 ret = -1;
90                 goto out;
91         }
92         password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
93         if (!password_s) {
94                 DEBUG(1,("ads_keytab_add_entry: failed to fetch machine password\n"));
95                 ret = -1;
96                 goto out;
97         }
98         password.data = password_s;
99         password.length = strlen(password_s);
100
101         /* Construct our principal */
102         name_to_fqdn(my_fqdn, global_myname());
103         strlower_m(my_fqdn);
104         asprintf(&princ_s, "%s/%s@%s", srvPrinc, my_fqdn, lp_realm());
105
106         ret = krb5_parse_name(context, princ_s, &princ);
107         if (ret) {
108                 DEBUG(1,("ads_keytab_add_entry: krb5_parse_name(%s) failed (%s)\n", princ_s, error_message(ret)));
109                 goto out;
110         }
111
112         kvno = (krb5_kvno) ads_get_kvno(ads, global_myname());
113         if (kvno == -1) {       /* -1 indicates failure, everything else is OK */
114                 DEBUG(1,("ads_keytab_add_entry: ads_get_kvno failed to determine the system's kvno.\n"));
115                 ret = -1;
116                 goto out;
117         }
118
119         /* Seek and delete old keytab entries */
120         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
121         if (ret != KRB5_KT_END && ret != ENOENT ) {
122                 DEBUG(3,("ads_keytab_add_entry: Will try to delete old keytab entries\n"));
123                 while(!krb5_kt_next_entry(context, keytab, &kt_entry, &cursor)) {
124                         BOOL compare_ok = False;
125
126                         ret = krb5_unparse_name(context, kt_entry.principal, &ktprinc);
127                         if (ret) {
128                                 DEBUG(1,("ads_keytab_add_entry: krb5_unparse_name failed (%s)\n", error_message(ret)));
129                                 goto out;
130                         }
131
132                         /*---------------------------------------------------------------------------
133                          * Save the entries with kvno - 1.   This is what microsoft does
134                          * to allow people with existing sessions that have kvno - 1 to still
135                          * work.   Otherwise, when the password for the machine changes, all
136                          * kerberizied sessions will 'break' until either the client reboots or
137                          * the client's session key expires and they get a new session ticket
138                          * with the new kvno.
139                          */
140
141 #ifdef HAVE_KRB5_KT_COMPARE
142                         compare_ok = ((krb5_kt_compare(context, &kt_entry, princ, 0, 0) == True) && (kt_entry.vno != kvno - 1));
143 #else
144                         compare_ok = ((strcmp(ktprinc, princ_s) == 0) && (kt_entry.vno != kvno - 1));
145 #endif
146                         krb5_free_unparsed_name(context, ktprinc);
147                         ktprinc = NULL;
148
149                         if (compare_ok) {
150                                 DEBUG(3,("ads_keytab_add_entry: Found old entry for principal: %s (kvno %d) - trying to remove it.\n",
151                                         princ_s, kt_entry.vno));
152                                 ret = krb5_kt_end_seq_get(context, keytab, &cursor);
153                                 ZERO_STRUCT(cursor);
154                                 if (ret) {
155                                         DEBUG(1,("ads_keytab_add_entry: krb5_kt_end_seq_get() failed (%s)\n",
156                                                 error_message(ret)));
157                                         goto out;
158                                 }
159                                 ret = krb5_kt_remove_entry(context, keytab, &kt_entry);
160                                 if (ret) {
161                                         DEBUG(1,("ads_keytab_add_entry: krb5_kt_remove_entry failed (%s)\n",
162                                                 error_message(ret)));
163                                         goto out;
164                                 }
165                                 ret = krb5_kt_start_seq_get(context, keytab, &cursor);
166                                 if (ret) {
167                                         DEBUG(1,("ads_keytab_add_entry: krb5_kt_start_seq failed (%s)\n",
168                                                 error_message(ret)));
169                                         goto out;
170                                 }
171                                 ret = smb_krb5_kt_free_entry(context, &kt_entry);
172                                 ZERO_STRUCT(kt_entry);
173                                 if (ret) {
174                                         DEBUG(1,("ads_keytab_add_entry: krb5_kt_remove_entry failed (%s)\n",
175                                                 error_message(ret)));
176                                         goto out;
177                                 }
178                                 continue;
179                         }
180
181                         /* Not a match, just free this entry and continue. */
182                         ret = smb_krb5_kt_free_entry(context, &kt_entry);
183                         ZERO_STRUCT(kt_entry);
184                         if (ret) {
185                                 DEBUG(1,("ads_keytab_add_entry: smb_krb5_kt_free_entry failed (%s)\n", error_message(ret)));
186                                 goto out;
187                         }
188                 }
189
190                 ret = krb5_kt_end_seq_get(context, keytab, &cursor);
191                 ZERO_STRUCT(cursor);
192                 if (ret) {
193                         DEBUG(1,("ads_keytab_add_entry: krb5_kt_end_seq_get failed (%s)\n",error_message(ret)));
194                         goto out;
195                 }
196         }
197
198         /* Ensure we don't double free. */
199         ZERO_STRUCT(kt_entry);
200         ZERO_STRUCT(cursor);
201
202         /* If we get here, we have deleted all the old entries with kvno's not equal to the current kvno-1. */
203
204         ret = get_kerberos_allowed_etypes(context,&enctypes);
205         if (ret) {
206                 DEBUG(1,("ads_keytab_add_entry: get_kerberos_allowed_etypes failed (%s)\n",error_message(ret)));
207                 goto out;
208         }
209
210         /* Now add keytab entries for all encryption types */
211         for (i = 0; enctypes[i]; i++) {
212                 krb5_keyblock *keyp;
213
214 #if !defined(HAVE_KRB5_KEYTAB_ENTRY_KEY) && !defined(HAVE_KRB5_KEYTAB_ENTRY_KEYBLOCK)
215 #error krb5_keytab_entry has no key or keyblock member
216 #endif
217 #ifdef HAVE_KRB5_KEYTAB_ENTRY_KEY               /* MIT */
218                 keyp = &kt_entry.key;
219 #endif
220 #ifdef HAVE_KRB5_KEYTAB_ENTRY_KEYBLOCK          /* Heimdal */
221                 keyp = &kt_entry.keyblock;
222 #endif
223                 if (create_kerberos_key_from_string(context, princ, &password, keyp, enctypes[i])) {
224                         continue;
225                 }
226
227                 kt_entry.principal = princ;
228                 kt_entry.vno       = kvno;
229
230                 DEBUG(3,("ads_keytab_add_entry: adding keytab entry for (%s) with encryption type (%d) and version (%d)\n",
231                         princ_s, enctypes[i], kt_entry.vno));
232                 ret = krb5_kt_add_entry(context, keytab, &kt_entry);
233                 krb5_free_keyblock_contents(context, keyp);
234                 ZERO_STRUCT(kt_entry);
235                 if (ret) {
236                         DEBUG(1,("ads_keytab_add_entry: adding entry to keytab failed (%s)\n", error_message(ret)));
237                         goto out;
238                 }
239         }
240
241         krb5_kt_close(context, keytab);
242         keytab = NULL; /* Done with keytab now. No double free. */
243
244         /* Update the LDAP with the SPN */
245         DEBUG(3,("ads_keytab_add_entry: Attempting to add/update '%s'\n", princ_s));
246         if (!ADS_ERR_OK(ads_add_service_principal_name(ads, global_myname(), srvPrinc))) {
247                 DEBUG(1,("ads_keytab_add_entry: ads_add_service_principcal_name failed.\n"));
248                 goto out;
249         }
250
251 out:
252
253         SAFE_FREE(principal);
254         SAFE_FREE(password_s);
255         SAFE_FREE(princ_s);
256
257         {
258                 krb5_keytab_entry zero_kt_entry;
259                 ZERO_STRUCT(zero_kt_entry);
260                 if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
261                         smb_krb5_kt_free_entry(context, &kt_entry);
262                 }
263         }
264         if (princ) {
265                 krb5_free_principal(context, princ);
266         }
267         if (enctypes) {
268                 free_kerberos_etypes(context, enctypes);
269         }
270
271         {
272                 krb5_kt_cursor zero_csr;
273                 ZERO_STRUCT(zero_csr);
274                 if ((memcmp(&cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
275                         krb5_kt_end_seq_get(context, keytab, &cursor);  
276                 }
277         }
278         if (keytab) {
279                 krb5_kt_close(context, keytab);
280         }
281         if (context) {
282                 krb5_free_context(context);
283         }
284         return (int)ret;
285 }
286
287 /**********************************************************************
288  Flushes all entries from the system keytab.
289 ***********************************************************************/
290
291 int ads_keytab_flush(ADS_STRUCT *ads)
292 {
293         krb5_error_code ret = 0;
294         krb5_context context = NULL;
295         krb5_keytab keytab = NULL;
296         krb5_kt_cursor cursor;
297         krb5_keytab_entry kt_entry;
298         krb5_kvno kvno;
299         char keytab_name[MAX_KEYTAB_NAME_LEN];
300
301         ZERO_STRUCT(kt_entry);
302         ZERO_STRUCT(cursor);
303
304         initialize_krb5_error_table();
305         ret = krb5_init_context(&context);
306         if (ret) {
307                 DEBUG(1,("ads_keytab_flush: could not krb5_init_context: %s\n",error_message(ret)));
308                 return ret;
309         }
310 #ifdef HAVE_WRFILE_KEYTAB
311         keytab_name[0] = 'W';
312         keytab_name[1] = 'R';
313         ret = krb5_kt_default_name(context, (char *) &keytab_name[2], MAX_KEYTAB_NAME_LEN - 4);
314 #else
315         ret = krb5_kt_default_name(context, (char *) &keytab_name[0], MAX_KEYTAB_NAME_LEN - 2);
316 #endif
317         if (ret) {
318                 DEBUG(1,("ads_keytab_flush: krb5_kt_default failed (%s)\n", error_message(ret)));
319                 goto out;
320         }
321         DEBUG(3,("ads_keytab_flush: Using default keytab: %s\n", (char *) &keytab_name));
322         ret = krb5_kt_resolve(context, (char *) &keytab_name, &keytab);
323         if (ret) {
324                 DEBUG(1,("ads_keytab_flush: krb5_kt_default failed (%s)\n", error_message(ret)));
325                 goto out;
326         }
327         ret = krb5_kt_resolve(context, (char *) &keytab_name, &keytab);
328         if (ret) {
329                 DEBUG(1,("ads_keytab_flush: krb5_kt_default failed (%s)\n", error_message(ret)));
330                 goto out;
331         }
332
333         kvno = (krb5_kvno) ads_get_kvno(ads, global_myname());
334         if (kvno == -1) {       /* -1 indicates a failure */
335                 DEBUG(1,("ads_keytab_flush: Error determining the system's kvno.\n"));
336                 goto out;
337         }
338
339         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
340         if (ret != KRB5_KT_END && ret != ENOENT) {
341                 while (!krb5_kt_next_entry(context, keytab, &kt_entry, &cursor)) {
342                         ret = krb5_kt_end_seq_get(context, keytab, &cursor);
343                         ZERO_STRUCT(cursor);
344                         if (ret) {
345                                 DEBUG(1,("ads_keytab_flush: krb5_kt_end_seq_get() failed (%s)\n",error_message(ret)));
346                                 goto out;
347                         }
348                         ret = krb5_kt_remove_entry(context, keytab, &kt_entry);
349                         if (ret) {
350                                 DEBUG(1,("ads_keytab_flush: krb5_kt_remove_entry failed (%s)\n",error_message(ret)));
351                                 goto out;
352                         }
353                         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
354                         if (ret) {
355                                 DEBUG(1,("ads_keytab_flush: krb5_kt_start_seq failed (%s)\n",error_message(ret)));
356                                 goto out;
357                         }
358                         ret = smb_krb5_kt_free_entry(context, &kt_entry);
359                         ZERO_STRUCT(kt_entry);
360                         if (ret) {
361                                 DEBUG(1,("ads_keytab_flush: krb5_kt_remove_entry failed (%s)\n",error_message(ret)));
362                                 goto out;
363                         }
364                 }
365         }
366
367         /* Ensure we don't double free. */
368         ZERO_STRUCT(kt_entry);
369         ZERO_STRUCT(cursor);
370
371         if (!ADS_ERR_OK(ads_clear_service_principal_names(ads, global_myname()))) {
372                 DEBUG(1,("ads_keytab_flush: Error while clearing service principal listings in LDAP.\n"));
373                 goto out;
374         }
375
376 out:
377
378         {
379                 krb5_keytab_entry zero_kt_entry;
380                 ZERO_STRUCT(zero_kt_entry);
381                 if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
382                         smb_krb5_kt_free_entry(context, &kt_entry);
383                 }
384         }
385         {
386                 krb5_kt_cursor zero_csr;
387                 ZERO_STRUCT(zero_csr);
388                 if ((memcmp(&cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
389                         krb5_kt_end_seq_get(context, keytab, &cursor);  
390                 }
391         }
392         if (keytab) {
393                 krb5_kt_close(context, keytab);
394         }
395         if (context) {
396                 krb5_free_context(context);
397         }
398         return ret;
399 }
400
401 /**********************************************************************
402  Adds all the required service principals to the system keytab.
403 ***********************************************************************/
404
405 int ads_keytab_create_default(ADS_STRUCT *ads)
406 {
407         krb5_error_code ret = 0;
408         krb5_context context = NULL;
409         krb5_keytab keytab = NULL;
410         krb5_kt_cursor cursor;
411         krb5_keytab_entry kt_entry;
412         krb5_kvno kvno;
413         int i, found = 0;
414         char **oldEntries = NULL;
415
416         ret = ads_keytab_add_entry(ads, "host");
417         if (ret) {
418                 DEBUG(1,("ads_keytab_create_default: ads_keytab_add_entry failed while adding 'host'.\n"));
419                 return ret;
420         }
421         ret = ads_keytab_add_entry(ads, "cifs");
422         if (ret) {
423                 DEBUG(1,("ads_keytab_create_default: ads_keytab_add_entry failed while adding 'cifs'.\n"));
424                 return ret;
425         }
426
427         kvno = (krb5_kvno) ads_get_kvno(ads, global_myname());
428         if (kvno == -1) {
429                 DEBUG(1,("ads_keytab_create_default: ads_get_kvno failed to determine the system's kvno.\n"));
430                 return -1;
431         }
432
433         DEBUG(3,("ads_keytab_create_default: Searching for keytab entries to preserve and update.\n"));
434         /* Now loop through the keytab and update any other existing entries... */
435
436         ZERO_STRUCT(kt_entry);
437         ZERO_STRUCT(cursor);
438
439         initialize_krb5_error_table();
440         ret = krb5_init_context(&context);
441         if (ret) {
442                 DEBUG(1,("ads_keytab_create_default: could not krb5_init_context: %s\n",error_message(ret)));
443                 return ret;
444         }
445         ret = krb5_kt_default(context, &keytab);
446         if (ret) {
447                 DEBUG(1,("ads_keytab_create_default: krb5_kt_default failed (%s)\n",error_message(ret)));
448                 goto done;
449         }
450
451         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
452         if (ret != KRB5_KT_END && ret != ENOENT ) {
453                 while ((ret = krb5_kt_next_entry(context, keytab, &kt_entry, &cursor)) == 0) {
454                         smb_krb5_kt_free_entry(context, &kt_entry);
455                         ZERO_STRUCT(kt_entry);
456                         found++;
457                 }
458         }
459         krb5_kt_end_seq_get(context, keytab, &cursor);
460         ZERO_STRUCT(cursor);
461
462         /*
463          * Hmmm. There is no "rewind" function for the keytab. This means we have a race condition
464          * where someone else could add entries after we've counted them. Re-open asap to minimise
465          * the race. JRA.
466          */
467         
468         DEBUG(3, ("ads_keytab_create_default: Found %d entries in the keytab.\n", found));
469         if (!found) {
470                 goto done;
471         }
472         oldEntries = (char **) malloc(found * sizeof(char *));
473         if (!oldEntries) {
474                 DEBUG(1,("ads_keytab_create_default: Failed to allocate space to store the old keytab entries (malloc failed?).\n"));
475                 ret = -1;
476                 goto done;
477         }
478         memset(oldEntries, '\0', found * sizeof(char *));
479
480         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
481         if (ret != KRB5_KT_END && ret != ENOENT ) {
482                 while ((ret = krb5_kt_next_entry(context, keytab, &kt_entry, &cursor)) == 0) {
483                         if (kt_entry.vno != kvno) {
484                                 char *ktprinc = NULL;
485                                 char *p;
486
487                                 /* This returns a malloc'ed string in ktprinc. */
488                                 ret = krb5_unparse_name(context, kt_entry.principal, &ktprinc);
489                                 if (ret) {
490                                         DEBUG(1,("krb5_unparse_name failed (%s)\n", error_message(ret)));
491                                         goto done;
492                                 }
493                                 /*
494                                  * From looking at the krb5 source they don't seem to take locale
495                                  * or mb strings into account. Maybe this is because they assume utf8 ?
496                                  * In this case we may need to convert from utf8 to mb charset here ? JRA.
497                                  */
498                                 p = strchr_m(ktprinc, '/');
499                                 if (p) {
500                                         *p = '\0';
501                                 }
502                                 for (i = 0; i < found; i++) {
503                                         if (!oldEntries[i]) {
504                                                 oldEntries[i] = ktprinc;
505                                                 break;
506                                         }
507                                         if (!strcmp(oldEntries[i], ktprinc)) {
508                                                 krb5_free_unparsed_name(context, ktprinc);
509                                                 break;
510                                         }
511                                 }
512                                 if (i == found) {
513                                         krb5_free_unparsed_name(context, ktprinc);
514                                 }
515                         }
516                         smb_krb5_kt_free_entry(context, &kt_entry);
517                         ZERO_STRUCT(kt_entry);
518                 }
519                 for (i = 0; oldEntries[i]; i++) {
520                         ret |= ads_keytab_add_entry(ads, oldEntries[i]);
521                         krb5_free_unparsed_name(context, oldEntries[i]);
522                 }
523                 krb5_kt_end_seq_get(context, keytab, &cursor);
524         }
525         ZERO_STRUCT(cursor);
526
527 done:
528
529         SAFE_FREE(oldEntries);
530
531         {
532                 krb5_keytab_entry zero_kt_entry;
533                 ZERO_STRUCT(zero_kt_entry);
534                 if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
535                         smb_krb5_kt_free_entry(context, &kt_entry);
536                 }
537         }
538         {
539                 krb5_kt_cursor zero_csr;
540                 ZERO_STRUCT(zero_csr);
541                 if ((memcmp(&cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) && keytab) {
542                         krb5_kt_end_seq_get(context, keytab, &cursor);  
543                 }
544         }
545         if (keytab) {
546                 krb5_kt_close(context, keytab);
547         }
548         if (context) {
549                 krb5_free_context(context);
550         }
551         return ret;
552 }
553 #endif /* HAVE_KRB5 */