1 /* -*- mode: C; c-file-style: "gnu" -*- */
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 *
22 */
23 #define DBUS_USERDB_INCLUDES_PRIVATE 1
24 #include "dbus-userdb.h"
25 #include "dbus-hash.h"
26 #include "dbus-test.h"
27 #include "dbus-internals.h"
28 #include "dbus-protocol.h"
29 #include <string.h>
30
31 /**
32 * @addtogroup DBusInternalsUtils
33 * @{
34 */
35
36 /**
37 * Frees the given #DBusUserInfo's members with _dbus_user_info_free()
38 * and also calls dbus_free() on the block itself
39 *
40 * @param info the info
41 */
42 void
_dbus_user_info_free_allocated(DBusUserInfo * info)43 _dbus_user_info_free_allocated (DBusUserInfo *info)
44 {
45 if (info == NULL) /* hash table will pass NULL */
46 return;
47
48 _dbus_user_info_free (info);
49 dbus_free (info);
50 }
51
52 /**
53 * Frees the given #DBusGroupInfo's members with _dbus_group_info_free()
54 * and also calls dbus_free() on the block itself
55 *
56 * @param info the info
57 */
58 void
_dbus_group_info_free_allocated(DBusGroupInfo * info)59 _dbus_group_info_free_allocated (DBusGroupInfo *info)
60 {
61 if (info == NULL) /* hash table will pass NULL */
62 return;
63
64 _dbus_group_info_free (info);
65 dbus_free (info);
66 }
67
68 /**
69 * Checks if a given string is actually a number
70 * and converts it if it is
71 *
72 * @param str the string to check
73 * @param num the memory location of the unsigned long to fill in
74 * @returns TRUE if str is a number and num is filled in
75 */
76 dbus_bool_t
_dbus_is_a_number(const DBusString * str,unsigned long * num)77 _dbus_is_a_number (const DBusString *str,
78 unsigned long *num)
79 {
80 int end;
81
82 if (_dbus_string_parse_int (str, 0, num, &end) &&
83 end == _dbus_string_get_length (str))
84 return TRUE;
85 else
86 return FALSE;
87 }
88
89 /**
90 * Looks up a uid or username in the user database. Only one of name
91 * or UID can be provided. There are wrapper functions for this that
92 * are better to use, this one does no locking or anything on the
93 * database and otherwise sort of sucks.
94 *
95 * @param db the database
96 * @param uid the user ID or #DBUS_UID_UNSET
97 * @param username username or #NULL
98 * @param error error to fill in
99 * @returns the entry in the database
100 */
101 DBusUserInfo*
_dbus_user_database_lookup(DBusUserDatabase * db,dbus_uid_t uid,const DBusString * username,DBusError * error)102 _dbus_user_database_lookup (DBusUserDatabase *db,
103 dbus_uid_t uid,
104 const DBusString *username,
105 DBusError *error)
106 {
107 DBusUserInfo *info;
108
109 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
110 _dbus_assert (uid != DBUS_UID_UNSET || username != NULL);
111
112 /* See if the username is really a number */
113 if (uid == DBUS_UID_UNSET)
114 {
115 unsigned long n;
116
117 if (_dbus_is_a_number (username, &n))
118 uid = n;
119 }
120
121 if (uid != DBUS_UID_UNSET)
122 info = _dbus_hash_table_lookup_ulong (db->users, uid);
123 else
124 info = _dbus_hash_table_lookup_string (db->users_by_name, _dbus_string_get_const_data (username));
125
126 if (info)
127 {
128 _dbus_verbose ("Using cache for UID "DBUS_UID_FORMAT" information\n",
129 info->uid);
130 return info;
131 }
132 else
133 {
134 if (uid != DBUS_UID_UNSET)
135 _dbus_verbose ("No cache for UID "DBUS_UID_FORMAT"\n",
136 uid);
137 else
138 _dbus_verbose ("No cache for user \"%s\"\n",
139 _dbus_string_get_const_data (username));
140
141 info = dbus_new0 (DBusUserInfo, 1);
142 if (info == NULL)
143 {
144 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
145 return NULL;
146 }
147
148 if (uid != DBUS_UID_UNSET)
149 {
150 if (!_dbus_user_info_fill_uid (info, uid, error))
151 {
152 _DBUS_ASSERT_ERROR_IS_SET (error);
153 _dbus_user_info_free_allocated (info);
154 return NULL;
155 }
156 }
157 else
158 {
159 if (!_dbus_user_info_fill (info, username, error))
160 {
161 _DBUS_ASSERT_ERROR_IS_SET (error);
162 _dbus_user_info_free_allocated (info);
163 return NULL;
164 }
165 }
166
167 /* be sure we don't use these after here */
168 uid = DBUS_UID_UNSET;
169 username = NULL;
170
171 /* insert into hash */
172 if (!_dbus_hash_table_insert_ulong (db->users, info->uid, info))
173 {
174 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
175 _dbus_user_info_free_allocated (info);
176 return NULL;
177 }
178
179 if (!_dbus_hash_table_insert_string (db->users_by_name,
180 info->username,
181 info))
182 {
183 _dbus_hash_table_remove_ulong (db->users, info->uid);
184 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
185 return NULL;
186 }
187
188 return info;
189 }
190 }
191
192 _DBUS_DEFINE_GLOBAL_LOCK(system_users);
193 static dbus_bool_t database_locked = FALSE;
194 static DBusUserDatabase *system_db = NULL;
195 static DBusString process_username;
196 static DBusString process_homedir;
197
198 static void
shutdown_system_db(void * data)199 shutdown_system_db (void *data)
200 {
201 _dbus_user_database_unref (system_db);
202 system_db = NULL;
203 _dbus_string_free (&process_username);
204 _dbus_string_free (&process_homedir);
205 }
206
207 static dbus_bool_t
init_system_db(void)208 init_system_db (void)
209 {
210 _dbus_assert (database_locked);
211
212 if (system_db == NULL)
213 {
214 DBusError error;
215 const DBusUserInfo *info;
216
217 system_db = _dbus_user_database_new ();
218 if (system_db == NULL)
219 return FALSE;
220
221 dbus_error_init (&error);
222
223 if (!_dbus_user_database_get_uid (system_db,
224 _dbus_getuid (),
225 &info,
226 &error))
227 {
228 _dbus_user_database_unref (system_db);
229 system_db = NULL;
230
231 if (dbus_error_has_name (&error, DBUS_ERROR_NO_MEMORY))
232 {
233 dbus_error_free (&error);
234 return FALSE;
235 }
236 else
237 {
238 /* This really should not happen. */
239 _dbus_warn ("Could not get password database information for UID of current process: %s\n",
240 error.message);
241 dbus_error_free (&error);
242 return FALSE;
243 }
244 }
245
246 if (!_dbus_string_init (&process_username))
247 {
248 _dbus_user_database_unref (system_db);
249 system_db = NULL;
250 return FALSE;
251 }
252
253 if (!_dbus_string_init (&process_homedir))
254 {
255 _dbus_string_free (&process_username);
256 _dbus_user_database_unref (system_db);
257 system_db = NULL;
258 return FALSE;
259 }
260
261 if (!_dbus_string_append (&process_username,
262 info->username) ||
263 !_dbus_string_append (&process_homedir,
264 info->homedir) ||
265 !_dbus_register_shutdown_func (shutdown_system_db, NULL))
266 {
267 _dbus_string_free (&process_username);
268 _dbus_string_free (&process_homedir);
269 _dbus_user_database_unref (system_db);
270 system_db = NULL;
271 return FALSE;
272 }
273 }
274
275 return TRUE;
276 }
277
278 /**
279 * Locks global system user database.
280 */
281 void
_dbus_user_database_lock_system(void)282 _dbus_user_database_lock_system (void)
283 {
284 _DBUS_LOCK (system_users);
285 database_locked = TRUE;
286 }
287
288 /**
289 * Unlocks global system user database.
290 */
291 void
_dbus_user_database_unlock_system(void)292 _dbus_user_database_unlock_system (void)
293 {
294 database_locked = FALSE;
295 _DBUS_UNLOCK (system_users);
296 }
297
298 /**
299 * Gets the system global user database;
300 * must be called with lock held (_dbus_user_database_lock_system()).
301 *
302 * @returns the database or #NULL if no memory
303 */
304 DBusUserDatabase*
_dbus_user_database_get_system(void)305 _dbus_user_database_get_system (void)
306 {
307 _dbus_assert (database_locked);
308
309 init_system_db ();
310
311 return system_db;
312 }
313
314 /**
315 * Gets username of user owning current process. The returned string
316 * is valid until dbus_shutdown() is called.
317 *
318 * @param username place to store pointer to username
319 * @returns #FALSE if no memory
320 */
321 dbus_bool_t
_dbus_username_from_current_process(const DBusString ** username)322 _dbus_username_from_current_process (const DBusString **username)
323 {
324 _dbus_user_database_lock_system ();
325 if (!init_system_db ())
326 {
327 _dbus_user_database_unlock_system ();
328 return FALSE;
329 }
330 *username = &process_username;
331 _dbus_user_database_unlock_system ();
332
333 return TRUE;
334 }
335
336 /**
337 * Gets homedir of user owning current process. The returned string
338 * is valid until dbus_shutdown() is called.
339 *
340 * @param homedir place to store pointer to homedir
341 * @returns #FALSE if no memory
342 */
343 dbus_bool_t
_dbus_homedir_from_current_process(const DBusString ** homedir)344 _dbus_homedir_from_current_process (const DBusString **homedir)
345 {
346 _dbus_user_database_lock_system ();
347 if (!init_system_db ())
348 {
349 _dbus_user_database_unlock_system ();
350 return FALSE;
351 }
352 *homedir = &process_homedir;
353 _dbus_user_database_unlock_system ();
354
355 return TRUE;
356 }
357
358 /**
359 * Gets the home directory for the given user.
360 *
361 * @param username the username
362 * @param homedir string to append home directory to
363 * @returns #TRUE if user existed and we appended their homedir
364 */
365 dbus_bool_t
_dbus_homedir_from_username(const DBusString * username,DBusString * homedir)366 _dbus_homedir_from_username (const DBusString *username,
367 DBusString *homedir)
368 {
369 DBusUserDatabase *db;
370 const DBusUserInfo *info;
371 _dbus_user_database_lock_system ();
372
373 db = _dbus_user_database_get_system ();
374 if (db == NULL)
375 {
376 _dbus_user_database_unlock_system ();
377 return FALSE;
378 }
379
380 if (!_dbus_user_database_get_username (db, username,
381 &info, NULL))
382 {
383 _dbus_user_database_unlock_system ();
384 return FALSE;
385 }
386
387 if (!_dbus_string_append (homedir, info->homedir))
388 {
389 _dbus_user_database_unlock_system ();
390 return FALSE;
391 }
392
393 _dbus_user_database_unlock_system ();
394 return TRUE;
395 }
396
397 /**
398 * Gets the credentials corresponding to the given username.
399 *
400 * @param username the username
401 * @param credentials credentials to fill in
402 * @returns #TRUE if the username existed and we got some credentials
403 */
404 dbus_bool_t
_dbus_credentials_from_username(const DBusString * username,DBusCredentials * credentials)405 _dbus_credentials_from_username (const DBusString *username,
406 DBusCredentials *credentials)
407 {
408 DBusUserDatabase *db;
409 const DBusUserInfo *info;
410 _dbus_user_database_lock_system ();
411
412 db = _dbus_user_database_get_system ();
413 if (db == NULL)
414 {
415 _dbus_user_database_unlock_system ();
416 return FALSE;
417 }
418
419 if (!_dbus_user_database_get_username (db, username,
420 &info, NULL))
421 {
422 _dbus_user_database_unlock_system ();
423 return FALSE;
424 }
425
426 credentials->pid = DBUS_PID_UNSET;
427 credentials->uid = info->uid;
428 credentials->gid = info->primary_gid;
429
430 _dbus_user_database_unlock_system ();
431 return TRUE;
432 }
433
434 /**
435 * Creates a new user database object used to look up and
436 * cache user information.
437 * @returns new database, or #NULL on out of memory
438 */
439 DBusUserDatabase*
_dbus_user_database_new(void)440 _dbus_user_database_new (void)
441 {
442 DBusUserDatabase *db;
443
444 db = dbus_new0 (DBusUserDatabase, 1);
445 if (db == NULL)
446 return NULL;
447
448 db->refcount = 1;
449
450 db->users = _dbus_hash_table_new (DBUS_HASH_ULONG,
451 NULL, (DBusFreeFunction) _dbus_user_info_free_allocated);
452
453 if (db->users == NULL)
454 goto failed;
455
456 db->groups = _dbus_hash_table_new (DBUS_HASH_ULONG,
457 NULL, (DBusFreeFunction) _dbus_group_info_free_allocated);
458
459 if (db->groups == NULL)
460 goto failed;
461
462 db->users_by_name = _dbus_hash_table_new (DBUS_HASH_STRING,
463 NULL, NULL);
464 if (db->users_by_name == NULL)
465 goto failed;
466
467 db->groups_by_name = _dbus_hash_table_new (DBUS_HASH_STRING,
468 NULL, NULL);
469 if (db->groups_by_name == NULL)
470 goto failed;
471
472 return db;
473
474 failed:
475 _dbus_user_database_unref (db);
476 return NULL;
477 }
478
479 /**
480 * Flush all information out of the user database.
481 */
482 void
_dbus_user_database_flush(DBusUserDatabase * db)483 _dbus_user_database_flush (DBusUserDatabase *db)
484 {
485 _dbus_hash_table_remove_all(db->users_by_name);
486 _dbus_hash_table_remove_all(db->groups_by_name);
487 _dbus_hash_table_remove_all(db->users);
488 _dbus_hash_table_remove_all(db->groups);
489 }
490
491 #ifdef DBUS_BUILD_TESTS
492 /**
493 * Increments refcount of user database.
494 * @param db the database
495 * @returns the database
496 */
497 DBusUserDatabase *
_dbus_user_database_ref(DBusUserDatabase * db)498 _dbus_user_database_ref (DBusUserDatabase *db)
499 {
500 _dbus_assert (db->refcount > 0);
501
502 db->refcount += 1;
503
504 return db;
505 }
506 #endif /* DBUS_BUILD_TESTS */
507
508 /**
509 * Decrements refcount of user database.
510 * @param db the database
511 */
512 void
_dbus_user_database_unref(DBusUserDatabase * db)513 _dbus_user_database_unref (DBusUserDatabase *db)
514 {
515 _dbus_assert (db->refcount > 0);
516
517 db->refcount -= 1;
518 if (db->refcount == 0)
519 {
520 if (db->users)
521 _dbus_hash_table_unref (db->users);
522
523 if (db->groups)
524 _dbus_hash_table_unref (db->groups);
525
526 if (db->users_by_name)
527 _dbus_hash_table_unref (db->users_by_name);
528
529 if (db->groups_by_name)
530 _dbus_hash_table_unref (db->groups_by_name);
531
532 dbus_free (db);
533 }
534 }
535
536 /**
537 * Gets the user information for the given UID,
538 * returned user info should not be freed.
539 *
540 * @param db user database
541 * @param uid the user ID
542 * @param info return location for const ref to user info
543 * @param error error location
544 * @returns #FALSE if error is set
545 */
546 dbus_bool_t
_dbus_user_database_get_uid(DBusUserDatabase * db,dbus_uid_t uid,const DBusUserInfo ** info,DBusError * error)547 _dbus_user_database_get_uid (DBusUserDatabase *db,
548 dbus_uid_t uid,
549 const DBusUserInfo **info,
550 DBusError *error)
551 {
552 *info = _dbus_user_database_lookup (db, uid, NULL, error);
553 return *info != NULL;
554 }
555
556 /**
557 * Gets the user information for the given username.
558 *
559 * @param db user database
560 * @param username the user name
561 * @param info return location for const ref to user info
562 * @param error error location
563 * @returns #FALSE if error is set
564 */
565 dbus_bool_t
_dbus_user_database_get_username(DBusUserDatabase * db,const DBusString * username,const DBusUserInfo ** info,DBusError * error)566 _dbus_user_database_get_username (DBusUserDatabase *db,
567 const DBusString *username,
568 const DBusUserInfo **info,
569 DBusError *error)
570 {
571 *info = _dbus_user_database_lookup (db, DBUS_UID_UNSET, username, error);
572 return *info != NULL;
573 }
574
575 /** @} */
576
577 /* Tests in dbus-userdb-util.c */
578