1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-userdb.c User database abstraction
3 *
4 * Copyright (C) 2003, 2004 Red Hat, Inc.
5 *
6 * Licensed under the Academic Free License version 2.1
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 *
22 */
23 #include <config.h>
24 #define DBUS_USERDB_INCLUDES_PRIVATE 1
25 #include "dbus-userdb.h"
26 #include "dbus-hash.h"
27 #include "dbus-test.h"
28 #include "dbus-internals.h"
29 #include "dbus-protocol.h"
30 #include "dbus-credentials.h"
31 #include <string.h>
32
33 /**
34 * @addtogroup DBusInternalsUtils
35 * @{
36 */
37
38 /**
39 * Frees the given #DBusUserInfo's members with _dbus_user_info_free()
40 * and also calls dbus_free() on the block itself
41 *
42 * @param info the info
43 */
44 void
_dbus_user_info_free_allocated(DBusUserInfo * info)45 _dbus_user_info_free_allocated (DBusUserInfo *info)
46 {
47 if (info == NULL) /* hash table will pass NULL */
48 return;
49
50 _dbus_user_info_free (info);
51 dbus_free (info);
52 }
53
54 /**
55 * Frees the given #DBusGroupInfo's members with _dbus_group_info_free()
56 * and also calls dbus_free() on the block itself
57 *
58 * @param info the info
59 */
60 void
_dbus_group_info_free_allocated(DBusGroupInfo * info)61 _dbus_group_info_free_allocated (DBusGroupInfo *info)
62 {
63 if (info == NULL) /* hash table will pass NULL */
64 return;
65
66 _dbus_group_info_free (info);
67 dbus_free (info);
68 }
69
70 /**
71 * Frees the members of info
72 * (but not info itself)
73 * @param info the user info struct
74 */
75 void
_dbus_user_info_free(DBusUserInfo * info)76 _dbus_user_info_free (DBusUserInfo *info)
77 {
78 dbus_free (info->group_ids);
79 dbus_free (info->username);
80 dbus_free (info->homedir);
81 }
82
83 /**
84 * Frees the members of info (but not info itself).
85 *
86 * @param info the group info
87 */
88 void
_dbus_group_info_free(DBusGroupInfo * info)89 _dbus_group_info_free (DBusGroupInfo *info)
90 {
91 dbus_free (info->groupname);
92 }
93
94 /**
95 * Checks if a given string is actually a number
96 * and converts it if it is
97 *
98 * @param str the string to check
99 * @param num the memory location of the unsigned long to fill in
100 * @returns TRUE if str is a number and num is filled in
101 */
102 dbus_bool_t
_dbus_is_a_number(const DBusString * str,unsigned long * num)103 _dbus_is_a_number (const DBusString *str,
104 unsigned long *num)
105 {
106 int end;
107
108 if (_dbus_string_parse_uint (str, 0, num, &end) &&
109 end == _dbus_string_get_length (str))
110 return TRUE;
111 else
112 return FALSE;
113 }
114
115 /**
116 * Looks up a uid or username in the user database. Only one of name
117 * or UID can be provided. There are wrapper functions for this that
118 * are better to use, this one does no locking or anything on the
119 * database and otherwise sort of sucks.
120 *
121 * @param db the database
122 * @param uid the user ID or #DBUS_UID_UNSET
123 * @param username username or #NULL
124 * @param error error to fill in
125 * @returns the entry in the database
126 */
127 DBusUserInfo*
_dbus_user_database_lookup(DBusUserDatabase * db,dbus_uid_t uid,const DBusString * username,DBusError * error)128 _dbus_user_database_lookup (DBusUserDatabase *db,
129 dbus_uid_t uid,
130 const DBusString *username,
131 DBusError *error)
132 {
133 DBusUserInfo *info;
134
135 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
136 _dbus_assert (uid != DBUS_UID_UNSET || username != NULL);
137
138 /* See if the username is really a number */
139 if (uid == DBUS_UID_UNSET)
140 {
141 unsigned long n;
142
143 if (_dbus_is_a_number (username, &n))
144 uid = n;
145 }
146
147 #ifdef DBUS_ENABLE_USERDB_CACHE
148 if (uid != DBUS_UID_UNSET)
149 info = _dbus_hash_table_lookup_uintptr (db->users, uid);
150 else
151 info = _dbus_hash_table_lookup_string (db->users_by_name, _dbus_string_get_const_data (username));
152
153 if (info)
154 {
155 _dbus_verbose ("Using cache for UID "DBUS_UID_FORMAT" information\n",
156 info->uid);
157 return info;
158 }
159 else
160 #else
161 if (1)
162 #endif
163 {
164 if (uid != DBUS_UID_UNSET)
165 _dbus_verbose ("No cache for UID "DBUS_UID_FORMAT"\n",
166 uid);
167 else
168 _dbus_verbose ("No cache for user \"%s\"\n",
169 _dbus_string_get_const_data (username));
170
171 info = dbus_new0 (DBusUserInfo, 1);
172 if (info == NULL)
173 {
174 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
175 return NULL;
176 }
177
178 if (uid != DBUS_UID_UNSET)
179 {
180 if (!_dbus_user_info_fill_uid (info, uid, error))
181 {
182 _DBUS_ASSERT_ERROR_IS_SET (error);
183 _dbus_user_info_free_allocated (info);
184 return NULL;
185 }
186 }
187 else
188 {
189 if (!_dbus_user_info_fill (info, username, error))
190 {
191 _DBUS_ASSERT_ERROR_IS_SET (error);
192 _dbus_user_info_free_allocated (info);
193 return NULL;
194 }
195 }
196
197 /* be sure we don't use these after here */
198 uid = DBUS_UID_UNSET;
199 username = NULL;
200
201 /* insert into hash */
202 if (!_dbus_hash_table_insert_uintptr (db->users, info->uid, info))
203 {
204 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
205 _dbus_user_info_free_allocated (info);
206 return NULL;
207 }
208
209 if (!_dbus_hash_table_insert_string (db->users_by_name,
210 info->username,
211 info))
212 {
213 _dbus_hash_table_remove_uintptr (db->users, info->uid);
214 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
215 return NULL;
216 }
217
218 return info;
219 }
220 }
221
222 static dbus_bool_t database_locked = FALSE;
223 static DBusUserDatabase *system_db = NULL;
224 static DBusString process_username;
225 static DBusString process_homedir;
226
227 static void
shutdown_system_db(void * data)228 shutdown_system_db (void *data)
229 {
230 if (system_db != NULL)
231 _dbus_user_database_unref (system_db);
232 system_db = NULL;
233 _dbus_string_free (&process_username);
234 _dbus_string_free (&process_homedir);
235 }
236
237 static dbus_bool_t
init_system_db(void)238 init_system_db (void)
239 {
240 _dbus_assert (database_locked);
241
242 if (system_db == NULL)
243 {
244 DBusError error = DBUS_ERROR_INIT;
245 const DBusUserInfo *info;
246
247 system_db = _dbus_user_database_new ();
248 if (system_db == NULL)
249 return FALSE;
250
251 if (!_dbus_user_database_get_uid (system_db,
252 _dbus_getuid (),
253 &info,
254 &error))
255 {
256 _dbus_user_database_unref (system_db);
257 system_db = NULL;
258
259 if (dbus_error_has_name (&error, DBUS_ERROR_NO_MEMORY))
260 {
261 dbus_error_free (&error);
262 return FALSE;
263 }
264 else
265 {
266 /* This really should not happen. */
267 _dbus_warn ("Could not get password database information for UID of current process: %s\n",
268 error.message);
269 dbus_error_free (&error);
270 return FALSE;
271 }
272 }
273
274 if (!_dbus_string_init (&process_username))
275 {
276 _dbus_user_database_unref (system_db);
277 system_db = NULL;
278 return FALSE;
279 }
280
281 if (!_dbus_string_init (&process_homedir))
282 {
283 _dbus_string_free (&process_username);
284 _dbus_user_database_unref (system_db);
285 system_db = NULL;
286 return FALSE;
287 }
288
289 if (!_dbus_string_append (&process_username,
290 info->username) ||
291 !_dbus_string_append (&process_homedir,
292 info->homedir) ||
293 !_dbus_register_shutdown_func (shutdown_system_db, NULL))
294 {
295 _dbus_string_free (&process_username);
296 _dbus_string_free (&process_homedir);
297 _dbus_user_database_unref (system_db);
298 system_db = NULL;
299 return FALSE;
300 }
301 }
302
303 return TRUE;
304 }
305
306 /**
307 * Locks global system user database.
308 */
309 void
_dbus_user_database_lock_system(void)310 _dbus_user_database_lock_system (void)
311 {
312 _DBUS_LOCK (system_users);
313 database_locked = TRUE;
314 }
315
316 /**
317 * Unlocks global system user database.
318 */
319 void
_dbus_user_database_unlock_system(void)320 _dbus_user_database_unlock_system (void)
321 {
322 database_locked = FALSE;
323 _DBUS_UNLOCK (system_users);
324 }
325
326 /**
327 * Gets the system global user database;
328 * must be called with lock held (_dbus_user_database_lock_system()).
329 *
330 * @returns the database or #NULL if no memory
331 */
332 DBusUserDatabase*
_dbus_user_database_get_system(void)333 _dbus_user_database_get_system (void)
334 {
335 _dbus_assert (database_locked);
336
337 init_system_db ();
338
339 return system_db;
340 }
341
342 /**
343 * Flushes the system global user database;
344 */
345 void
_dbus_user_database_flush_system(void)346 _dbus_user_database_flush_system (void)
347 {
348 _dbus_user_database_lock_system ();
349
350 if (system_db != NULL)
351 _dbus_user_database_flush (system_db);
352
353 _dbus_user_database_unlock_system ();
354 }
355
356 /**
357 * Gets username of user owning current process. The returned string
358 * is valid until dbus_shutdown() is called.
359 *
360 * @param username place to store pointer to username
361 * @returns #FALSE if no memory
362 */
363 dbus_bool_t
_dbus_username_from_current_process(const DBusString ** username)364 _dbus_username_from_current_process (const DBusString **username)
365 {
366 _dbus_user_database_lock_system ();
367 if (!init_system_db ())
368 {
369 _dbus_user_database_unlock_system ();
370 return FALSE;
371 }
372 *username = &process_username;
373 _dbus_user_database_unlock_system ();
374
375 return TRUE;
376 }
377
378 /**
379 * Gets homedir of user owning current process. The returned string
380 * is valid until dbus_shutdown() is called.
381 *
382 * @param homedir place to store pointer to homedir
383 * @returns #FALSE if no memory
384 */
385 dbus_bool_t
_dbus_homedir_from_current_process(const DBusString ** homedir)386 _dbus_homedir_from_current_process (const DBusString **homedir)
387 {
388 _dbus_user_database_lock_system ();
389 if (!init_system_db ())
390 {
391 _dbus_user_database_unlock_system ();
392 return FALSE;
393 }
394 *homedir = &process_homedir;
395 _dbus_user_database_unlock_system ();
396
397 return TRUE;
398 }
399
400 /**
401 * Gets the home directory for the given user.
402 *
403 * @param username the username
404 * @param homedir string to append home directory to
405 * @returns #TRUE if user existed and we appended their homedir
406 */
407 dbus_bool_t
_dbus_homedir_from_username(const DBusString * username,DBusString * homedir)408 _dbus_homedir_from_username (const DBusString *username,
409 DBusString *homedir)
410 {
411 DBusUserDatabase *db;
412 const DBusUserInfo *info;
413 _dbus_user_database_lock_system ();
414
415 db = _dbus_user_database_get_system ();
416 if (db == NULL)
417 {
418 _dbus_user_database_unlock_system ();
419 return FALSE;
420 }
421
422 if (!_dbus_user_database_get_username (db, username,
423 &info, NULL))
424 {
425 _dbus_user_database_unlock_system ();
426 return FALSE;
427 }
428
429 if (!_dbus_string_append (homedir, info->homedir))
430 {
431 _dbus_user_database_unlock_system ();
432 return FALSE;
433 }
434
435 _dbus_user_database_unlock_system ();
436 return TRUE;
437 }
438
439 /**
440 * Gets the home directory for the given user.
441 *
442 * @param uid the uid
443 * @param homedir string to append home directory to
444 * @returns #TRUE if user existed and we appended their homedir
445 */
446 dbus_bool_t
_dbus_homedir_from_uid(dbus_uid_t uid,DBusString * homedir)447 _dbus_homedir_from_uid (dbus_uid_t uid,
448 DBusString *homedir)
449 {
450 DBusUserDatabase *db;
451 const DBusUserInfo *info;
452 _dbus_user_database_lock_system ();
453
454 db = _dbus_user_database_get_system ();
455 if (db == NULL)
456 {
457 _dbus_user_database_unlock_system ();
458 return FALSE;
459 }
460
461 if (!_dbus_user_database_get_uid (db, uid,
462 &info, NULL))
463 {
464 _dbus_user_database_unlock_system ();
465 return FALSE;
466 }
467
468 if (!_dbus_string_append (homedir, info->homedir))
469 {
470 _dbus_user_database_unlock_system ();
471 return FALSE;
472 }
473
474 _dbus_user_database_unlock_system ();
475 return TRUE;
476 }
477
478 /**
479 * Adds the credentials corresponding to the given username.
480 *
481 * Used among other purposes to parses a desired identity provided
482 * from a client in the auth protocol. On UNIX this means parsing a
483 * UID, on Windows probably parsing an SID string.
484 *
485 * @todo this is broken because it treats OOM and parse error
486 * the same way. Needs a #DBusError.
487 *
488 * @param credentials credentials to fill in
489 * @param username the username
490 * @returns #TRUE if the username existed and we got some credentials
491 */
492 dbus_bool_t
_dbus_credentials_add_from_user(DBusCredentials * credentials,const DBusString * username)493 _dbus_credentials_add_from_user (DBusCredentials *credentials,
494 const DBusString *username)
495 {
496 DBusUserDatabase *db;
497 const DBusUserInfo *info;
498
499 _dbus_user_database_lock_system ();
500
501 db = _dbus_user_database_get_system ();
502 if (db == NULL)
503 {
504 _dbus_user_database_unlock_system ();
505 return FALSE;
506 }
507
508 if (!_dbus_user_database_get_username (db, username,
509 &info, NULL))
510 {
511 _dbus_user_database_unlock_system ();
512 return FALSE;
513 }
514
515 if (!_dbus_credentials_add_unix_uid(credentials, info->uid))
516 {
517 _dbus_user_database_unlock_system ();
518 return FALSE;
519 }
520
521 _dbus_user_database_unlock_system ();
522 return TRUE;
523 }
524
525 /**
526 * Creates a new user database object used to look up and
527 * cache user information.
528 * @returns new database, or #NULL on out of memory
529 */
530 DBusUserDatabase*
_dbus_user_database_new(void)531 _dbus_user_database_new (void)
532 {
533 DBusUserDatabase *db;
534
535 db = dbus_new0 (DBusUserDatabase, 1);
536 if (db == NULL)
537 return NULL;
538
539 db->refcount = 1;
540
541 db->users = _dbus_hash_table_new (DBUS_HASH_UINTPTR,
542 NULL, (DBusFreeFunction) _dbus_user_info_free_allocated);
543
544 if (db->users == NULL)
545 goto failed;
546
547 db->groups = _dbus_hash_table_new (DBUS_HASH_UINTPTR,
548 NULL, (DBusFreeFunction) _dbus_group_info_free_allocated);
549
550 if (db->groups == NULL)
551 goto failed;
552
553 db->users_by_name = _dbus_hash_table_new (DBUS_HASH_STRING,
554 NULL, NULL);
555 if (db->users_by_name == NULL)
556 goto failed;
557
558 db->groups_by_name = _dbus_hash_table_new (DBUS_HASH_STRING,
559 NULL, NULL);
560 if (db->groups_by_name == NULL)
561 goto failed;
562
563 return db;
564
565 failed:
566 _dbus_user_database_unref (db);
567 return NULL;
568 }
569
570 /**
571 * Flush all information out of the user database.
572 */
573 void
_dbus_user_database_flush(DBusUserDatabase * db)574 _dbus_user_database_flush (DBusUserDatabase *db)
575 {
576 _dbus_hash_table_remove_all(db->users_by_name);
577 _dbus_hash_table_remove_all(db->groups_by_name);
578 _dbus_hash_table_remove_all(db->users);
579 _dbus_hash_table_remove_all(db->groups);
580 }
581
582 #ifdef DBUS_BUILD_TESTS
583 /**
584 * Increments refcount of user database.
585 * @param db the database
586 * @returns the database
587 */
588 DBusUserDatabase *
_dbus_user_database_ref(DBusUserDatabase * db)589 _dbus_user_database_ref (DBusUserDatabase *db)
590 {
591 _dbus_assert (db->refcount > 0);
592
593 db->refcount += 1;
594
595 return db;
596 }
597 #endif /* DBUS_BUILD_TESTS */
598
599 /**
600 * Decrements refcount of user database.
601 * @param db the database
602 */
603 void
_dbus_user_database_unref(DBusUserDatabase * db)604 _dbus_user_database_unref (DBusUserDatabase *db)
605 {
606 _dbus_assert (db->refcount > 0);
607
608 db->refcount -= 1;
609 if (db->refcount == 0)
610 {
611 if (db->users)
612 _dbus_hash_table_unref (db->users);
613
614 if (db->groups)
615 _dbus_hash_table_unref (db->groups);
616
617 if (db->users_by_name)
618 _dbus_hash_table_unref (db->users_by_name);
619
620 if (db->groups_by_name)
621 _dbus_hash_table_unref (db->groups_by_name);
622
623 dbus_free (db);
624 }
625 }
626
627 /**
628 * Gets the user information for the given UID,
629 * returned user info should not be freed.
630 *
631 * @param db user database
632 * @param uid the user ID
633 * @param info return location for const ref to user info
634 * @param error error location
635 * @returns #FALSE if error is set
636 */
637 dbus_bool_t
_dbus_user_database_get_uid(DBusUserDatabase * db,dbus_uid_t uid,const DBusUserInfo ** info,DBusError * error)638 _dbus_user_database_get_uid (DBusUserDatabase *db,
639 dbus_uid_t uid,
640 const DBusUserInfo **info,
641 DBusError *error)
642 {
643 *info = _dbus_user_database_lookup (db, uid, NULL, error);
644 return *info != NULL;
645 }
646
647 /**
648 * Gets the user information for the given username.
649 *
650 * @param db user database
651 * @param username the user name
652 * @param info return location for const ref to user info
653 * @param error error location
654 * @returns #FALSE if error is set
655 */
656 dbus_bool_t
_dbus_user_database_get_username(DBusUserDatabase * db,const DBusString * username,const DBusUserInfo ** info,DBusError * error)657 _dbus_user_database_get_username (DBusUserDatabase *db,
658 const DBusString *username,
659 const DBusUserInfo **info,
660 DBusError *error)
661 {
662 *info = _dbus_user_database_lookup (db, DBUS_UID_UNSET, username, error);
663 return *info != NULL;
664 }
665
666 /** @} */
667
668 /* Tests in dbus-userdb-util.c */
669