D-Bus  1.14.10
dbus-userdb.c
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 /* It isn't obvious from its name, but this file is part of the Unix
34  * system-dependent part of libdbus. Windows has a parallel
35  * implementation of some of it in dbus-sysdeps-win.c. */
36 #if defined(DBUS_WIN) || !defined(DBUS_UNIX)
37 #error "This file only makes sense on Unix OSs"
38 #endif
39 
45 static DBusUserInfo *
46 _dbus_user_info_ref (DBusUserInfo *info)
47 {
48  _dbus_assert (info->refcount > 0);
49  _dbus_assert (info->refcount < SIZE_MAX);
50  info->refcount++;
51  return info;
52 }
53 
61 void
63 {
64  if (info == NULL) /* hash table will pass NULL */
65  return;
66 
67  _dbus_assert (info->refcount > 0);
68  _dbus_assert (info->refcount < SIZE_MAX);
69 
70  if (--info->refcount > 0)
71  return;
72 
73  _dbus_user_info_free (info);
74  dbus_free (info);
75 }
76 
84 void
86 {
87  if (info == NULL) /* hash table will pass NULL */
88  return;
89 
90  _dbus_assert (info->refcount > 0);
91  _dbus_assert (info->refcount < SIZE_MAX);
92 
93  if (--info->refcount > 0)
94  return;
95 
96  _dbus_group_info_free (info);
97  dbus_free (info);
98 }
99 
105 void
107 {
108  dbus_free (info->group_ids);
109  dbus_free (info->username);
110  dbus_free (info->homedir);
111 }
112 
118 void
120 {
121  dbus_free (info->groupname);
122 }
123 
134  unsigned long *num)
135 {
136  int end;
137 
138  if (_dbus_string_parse_uint (str, 0, num, &end) &&
139  end == _dbus_string_get_length (str))
140  return TRUE;
141  else
142  return FALSE;
143 }
144 
157 const DBusUserInfo *
158 _dbus_user_database_lookup (DBusUserDatabase *db,
159  dbus_uid_t uid,
160  const DBusString *username,
161  DBusError *error)
162 {
163  DBusUserInfo *info;
164 
165  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
166  _dbus_assert (uid != DBUS_UID_UNSET || username != NULL);
167 
168  /* See if the username is really a number */
169  if (uid == DBUS_UID_UNSET)
170  {
171  unsigned long n;
172 
173  if (_dbus_is_a_number (username, &n))
174  uid = n;
175  }
176 
177  if (uid != DBUS_UID_UNSET)
178  info = _dbus_hash_table_lookup_uintptr (db->users, uid);
179  else
180  info = _dbus_hash_table_lookup_string (db->users_by_name, _dbus_string_get_const_data (username));
181 
182  if (info)
183  {
184  _dbus_verbose ("Using cache for UID "DBUS_UID_FORMAT" information\n",
185  info->uid);
186  return info;
187  }
188  else
189  {
190  if (uid != DBUS_UID_UNSET)
191  _dbus_verbose ("No cache for UID "DBUS_UID_FORMAT"\n",
192  uid);
193  else
194  _dbus_verbose ("No cache for user \"%s\"\n",
195  _dbus_string_get_const_data (username));
196 
197  info = dbus_new0 (DBusUserInfo, 1);
198  if (info == NULL)
199  {
201  return NULL;
202  }
203  info->refcount = 1;
204 
205  if (uid != DBUS_UID_UNSET)
206  {
207  if (!_dbus_user_info_fill_uid (info, uid, error))
208  {
209  _DBUS_ASSERT_ERROR_IS_SET (error);
210  _dbus_user_info_unref (info);
211  return NULL;
212  }
213  }
214  else
215  {
216  if (!_dbus_user_info_fill (info, username, error))
217  {
218  _DBUS_ASSERT_ERROR_IS_SET (error);
219  _dbus_user_info_unref (info);
220  return NULL;
221  }
222  }
223 
224  /* be sure we don't use these after here */
225  uid = DBUS_UID_UNSET;
226  username = NULL;
227 
228  /* insert into hash */
229  if (_dbus_hash_table_insert_uintptr (db->users, info->uid, info))
230  {
231  _dbus_user_info_ref (info);
232  }
233  else
234  {
236  _dbus_user_info_unref (info);
237  return NULL;
238  }
239 
240  if (_dbus_hash_table_insert_string (db->users_by_name,
241  info->username,
242  info))
243  {
244  _dbus_user_info_ref (info);
245  }
246  else
247  {
248  _dbus_hash_table_remove_uintptr (db->users, info->uid);
250  _dbus_user_info_unref (info);
251  return NULL;
252  }
253 
254  _dbus_user_info_unref (info);
255 
256  /* Return a borrowed pointer to the DBusUserInfo owned by the
257  * hash tables */
258  return info;
259  }
260 }
261 
262 /* Protected by _DBUS_LOCK_system_users */
263 static dbus_bool_t database_locked = FALSE;
264 static DBusUserDatabase *system_db = NULL;
265 static DBusString process_username;
266 static DBusString process_homedir;
267 
268 static void
269 shutdown_system_db (void *data)
270 {
271  if (system_db != NULL)
272  _dbus_user_database_unref (system_db);
273  system_db = NULL;
274  _dbus_string_free (&process_username);
275  _dbus_string_free (&process_homedir);
276 }
277 
278 static dbus_bool_t
279 init_system_db (void)
280 {
281  _dbus_assert (database_locked);
282 
283  if (system_db == NULL)
284  {
285  DBusError error = DBUS_ERROR_INIT;
286  const DBusUserInfo *info;
287 
288  system_db = _dbus_user_database_new ();
289  if (system_db == NULL)
290  return FALSE;
291 
292  if (!_dbus_user_database_get_uid (system_db,
293  _dbus_getuid (),
294  &info,
295  &error))
296  {
297  _dbus_user_database_unref (system_db);
298  system_db = NULL;
299 
301  {
302  dbus_error_free (&error);
303  return FALSE;
304  }
305  else
306  {
307  /* This really should not happen. */
308  _dbus_warn ("Could not get password database information for UID of current process: %s",
309  error.message);
310  dbus_error_free (&error);
311  return FALSE;
312  }
313  }
314 
315  if (!_dbus_string_init (&process_username))
316  {
317  _dbus_user_database_unref (system_db);
318  system_db = NULL;
319  return FALSE;
320  }
321 
322  if (!_dbus_string_init (&process_homedir))
323  {
324  _dbus_string_free (&process_username);
325  _dbus_user_database_unref (system_db);
326  system_db = NULL;
327  return FALSE;
328  }
329 
330  if (!_dbus_string_append (&process_username,
331  info->username) ||
332  !_dbus_string_append (&process_homedir,
333  info->homedir) ||
334  !_dbus_register_shutdown_func (shutdown_system_db, NULL))
335  {
336  _dbus_string_free (&process_username);
337  _dbus_string_free (&process_homedir);
338  _dbus_user_database_unref (system_db);
339  system_db = NULL;
340  return FALSE;
341  }
342  }
343 
344  return TRUE;
345 }
346 
352 {
353  if (_DBUS_LOCK (system_users))
354  {
355  database_locked = TRUE;
356  return TRUE;
357  }
358  else
359  {
360  return FALSE;
361  }
362 }
363 
367 void
369 {
370  database_locked = FALSE;
371  _DBUS_UNLOCK (system_users);
372 }
373 
380 DBusUserDatabase*
382 {
383  _dbus_assert (database_locked);
384 
385  init_system_db ();
386 
387  return system_db;
388 }
389 
393 void
395 {
397  {
398  /* nothing to flush */
399  return;
400  }
401 
402  if (system_db != NULL)
403  _dbus_user_database_flush (system_db);
404 
406 }
407 
417 {
419  return FALSE;
420 
421  if (!init_system_db ())
422  {
424  return FALSE;
425  }
426  *username = &process_username;
428 
429  return TRUE;
430 }
431 
441 {
443  return FALSE;
444 
445  if (!init_system_db ())
446  {
448  return FALSE;
449  }
450  *homedir = &process_homedir;
452 
453  return TRUE;
454 }
455 
465  DBusString *homedir)
466 {
467  DBusUserDatabase *db;
468  const DBusUserInfo *info;
469 
470  if (uid == _dbus_getuid () && uid == _dbus_geteuid ())
471  {
472  const char *from_environment;
473 
474  from_environment = _dbus_getenv ("HOME");
475 
476  if (from_environment != NULL)
477  return _dbus_string_append (homedir, from_environment);
478  }
479 
480  /* FIXME: this can't distinguish ENOMEM from other errors */
482  return FALSE;
483 
485  if (db == NULL)
486  {
488  return FALSE;
489  }
490 
491  if (!_dbus_user_database_get_uid (db, uid,
492  &info, NULL))
493  {
495  return FALSE;
496  }
497 
498  if (!_dbus_string_append (homedir, info->homedir))
499  {
501  return FALSE;
502  }
503 
505  return TRUE;
506 }
507 
524  const DBusString *username,
525  DBusCredentialsAddFlags flags,
526  DBusError *error)
527 {
528  DBusUserDatabase *db;
529  const DBusUserInfo *info;
530  unsigned long uid = DBUS_UID_UNSET;
531 
532  /* Fast-path for the common case: if the "username" is all-numeric,
533  * then it's a Unix uid. This is true regardless of whether that uid
534  * exists in NSS or /etc/passwd or equivalent. */
535  if (_dbus_is_a_number (username, &uid))
536  {
537  _DBUS_STATIC_ASSERT (sizeof (uid) == sizeof (dbus_uid_t));
538 
539  if (_dbus_credentials_add_unix_uid (credentials, uid))
540  {
541  return TRUE;
542  }
543  else
544  {
545  _DBUS_SET_OOM (error);
546  return FALSE;
547  }
548  }
549 
550  /* If we aren't allowed to look in NSS or /etc/passwd, fail now. */
551  if (!(flags & DBUS_CREDENTIALS_ADD_FLAGS_USER_DATABASE))
552  {
554  "Expected a numeric Unix uid");
555  return FALSE;
556  }
557 
559  {
560  _DBUS_SET_OOM (error);
561  return FALSE;
562  }
563 
565  if (db == NULL)
566  {
568  _DBUS_SET_OOM (error);
569  return FALSE;
570  }
571 
572  if (!_dbus_user_database_get_username (db, username,
573  &info, error))
574  {
576  return FALSE;
577  }
578 
579  if (!_dbus_credentials_add_unix_uid(credentials, info->uid))
580  {
582  _DBUS_SET_OOM (error);
583  return FALSE;
584  }
585 
587  return TRUE;
588 }
589 
595 DBusUserDatabase*
597 {
598  DBusUserDatabase *db;
599 
600  db = dbus_new0 (DBusUserDatabase, 1);
601  if (db == NULL)
602  return NULL;
603 
604  db->refcount = 1;
605 
608 
609  if (db->users == NULL)
610  goto failed;
611 
614 
615  if (db->groups == NULL)
616  goto failed;
617 
618  db->users_by_name = _dbus_hash_table_new (DBUS_HASH_STRING,
620  if (db->users_by_name == NULL)
621  goto failed;
622 
623  db->groups_by_name = _dbus_hash_table_new (DBUS_HASH_STRING,
625  if (db->groups_by_name == NULL)
626  goto failed;
627 
628  return db;
629 
630  failed:
632  return NULL;
633 }
634 
638 void
639 _dbus_user_database_flush (DBusUserDatabase *db)
640 {
641  _dbus_hash_table_remove_all(db->users_by_name);
642  _dbus_hash_table_remove_all(db->groups_by_name);
643  _dbus_hash_table_remove_all(db->users);
644  _dbus_hash_table_remove_all(db->groups);
645 }
646 
647 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
653 DBusUserDatabase *
654 _dbus_user_database_ref (DBusUserDatabase *db)
655 {
656  _dbus_assert (db->refcount > 0);
657 
658  db->refcount += 1;
659 
660  return db;
661 }
662 #endif /* DBUS_ENABLE_EMBEDDED_TESTS */
663 
668 void
669 _dbus_user_database_unref (DBusUserDatabase *db)
670 {
671  _dbus_assert (db->refcount > 0);
672 
673  db->refcount -= 1;
674  if (db->refcount == 0)
675  {
676  if (db->users)
677  _dbus_hash_table_unref (db->users);
678 
679  if (db->groups)
680  _dbus_hash_table_unref (db->groups);
681 
682  if (db->users_by_name)
683  _dbus_hash_table_unref (db->users_by_name);
684 
685  if (db->groups_by_name)
686  _dbus_hash_table_unref (db->groups_by_name);
687 
688  dbus_free (db);
689  }
690 }
691 
703 _dbus_user_database_get_uid (DBusUserDatabase *db,
704  dbus_uid_t uid,
705  const DBusUserInfo **info,
706  DBusError *error)
707 {
708  *info = _dbus_user_database_lookup (db, uid, NULL, error);
709  return *info != NULL;
710 }
711 
722 _dbus_user_database_get_username (DBusUserDatabase *db,
723  const DBusString *username,
724  const DBusUserInfo **info,
725  DBusError *error)
726 {
727  *info = _dbus_user_database_lookup (db, DBUS_UID_UNSET, username, error);
728  return *info != NULL;
729 }
730 
733 /* Tests in dbus-userdb-util.c */
dbus_bool_t _dbus_credentials_add_unix_uid(DBusCredentials *credentials, dbus_uid_t uid)
Add a UNIX user ID to the credentials.
#define DBUS_ERROR_INIT
Expands to a suitable initializer for a DBusError on the stack.
Definition: dbus-errors.h:62
dbus_bool_t dbus_error_has_name(const DBusError *error, const char *name)
Checks whether the error is set and has the given name.
Definition: dbus-errors.c:302
void dbus_set_error(DBusError *error, const char *name, const char *format,...)
Assigns an error name and message to a DBusError.
Definition: dbus-errors.c:354
void dbus_error_free(DBusError *error)
Frees an error that's been set (or just initialized), then reinitializes the error as in dbus_error_i...
Definition: dbus-errors.c:211
dbus_bool_t _dbus_hash_table_remove_uintptr(DBusHashTable *table, uintptr_t key)
Removes the hash entry for the given key.
Definition: dbus-hash.c:1242
dbus_bool_t _dbus_hash_table_insert_string(DBusHashTable *table, char *key, void *value)
Creates a hash entry with the given key and value.
Definition: dbus-hash.c:1277
void * _dbus_hash_table_lookup_uintptr(DBusHashTable *table, uintptr_t key)
Looks up the value for a given integer in a hash table of type DBUS_HASH_UINTPTR.
Definition: dbus-hash.c:1162
void _dbus_hash_table_unref(DBusHashTable *table)
Decrements the reference count for a hash table, freeing the hash table if the count reaches zero.
Definition: dbus-hash.c:367
DBusHashTable * _dbus_hash_table_new(DBusHashType type, DBusFreeFunction key_free_function, DBusFreeFunction value_free_function)
Constructs a new hash table.
Definition: dbus-hash.c:291
void * _dbus_hash_table_lookup_string(DBusHashTable *table, const char *key)
Looks up the value for a given string in a hash table of type DBUS_HASH_STRING.
Definition: dbus-hash.c:1112
void _dbus_hash_table_remove_all(DBusHashTable *table)
Removed all entries from a hash table.
Definition: dbus-hash.c:424
dbus_bool_t _dbus_hash_table_insert_uintptr(DBusHashTable *table, uintptr_t key, void *value)
Creates a hash entry with the given key and value.
Definition: dbus-hash.c:1352
@ DBUS_HASH_UINTPTR
Hash keys are integer capable to hold a pointer.
Definition: dbus-hash.h:71
@ DBUS_HASH_STRING
Hash keys are strings.
Definition: dbus-hash.h:69
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
dbus_bool_t _dbus_user_database_lock_system(void)
Locks global system user database.
Definition: dbus-userdb.c:351
dbus_bool_t _dbus_homedir_from_current_process(const DBusString **homedir)
Gets homedir of user owning current process.
Definition: dbus-userdb.c:440
#define _DBUS_UNLOCK(name)
Unlocks a global lock.
DBusUserDatabase * _dbus_user_database_new(void)
Creates a new user database object used to look up and cache user information.
Definition: dbus-userdb.c:596
#define _DBUS_LOCK(name)
Locks a global lock, initializing it first if necessary.
void _dbus_user_database_unlock_system(void)
Unlocks global system user database.
Definition: dbus-userdb.c:368
void _dbus_user_database_unref(DBusUserDatabase *db)
Decrements refcount of user database.
Definition: dbus-userdb.c:669
const DBusUserInfo * _dbus_user_database_lookup(DBusUserDatabase *db, dbus_uid_t uid, const DBusString *username, DBusError *error)
Looks up a uid or username in the user database.
Definition: dbus-userdb.c:158
dbus_bool_t _dbus_credentials_add_from_user(DBusCredentials *credentials, const DBusString *username, DBusCredentialsAddFlags flags, DBusError *error)
Adds the credentials corresponding to the given username.
Definition: dbus-userdb.c:523
dbus_bool_t _dbus_user_database_get_uid(DBusUserDatabase *db, dbus_uid_t uid, const DBusUserInfo **info, DBusError *error)
Gets the user information for the given UID, returned user info should not be freed.
Definition: dbus-userdb.c:703
void _dbus_user_database_flush_system(void)
Flushes the system global user database;.
Definition: dbus-userdb.c:394
DBusUserDatabase * _dbus_user_database_get_system(void)
Gets the system global user database; must be called with lock held (_dbus_user_database_lock_system(...
Definition: dbus-userdb.c:381
void _dbus_group_info_unref(DBusGroupInfo *info)
Decrements the reference count.
Definition: dbus-userdb.c:85
void _dbus_user_info_unref(DBusUserInfo *info)
Decrements the reference count.
Definition: dbus-userdb.c:62
dbus_bool_t _dbus_username_from_current_process(const DBusString **username)
Gets username of user owning current process.
Definition: dbus-userdb.c:416
void _dbus_user_info_free(DBusUserInfo *info)
Frees the members of info (but not info itself)
Definition: dbus-userdb.c:106
void _dbus_user_database_flush(DBusUserDatabase *db)
Flush all information out of the user database.
Definition: dbus-userdb.c:639
dbus_bool_t _dbus_homedir_from_uid(dbus_uid_t uid, DBusString *homedir)
Gets the home directory for the given user.
Definition: dbus-userdb.c:464
void _dbus_warn(const char *format,...)
Prints a warning message to stderr.
void _dbus_group_info_free(DBusGroupInfo *info)
Frees the members of info (but not info itself).
Definition: dbus-userdb.c:119
dbus_bool_t _dbus_user_database_get_username(DBusUserDatabase *db, const DBusString *username, const DBusUserInfo **info, DBusError *error)
Gets the user information for the given username.
Definition: dbus-userdb.c:722
dbus_bool_t _dbus_is_a_number(const DBusString *str, unsigned long *num)
Checks if a given string is actually a number and converts it if it is.
Definition: dbus-userdb.c:133
#define NULL
A null pointer, defined appropriately for C or C++.
#define TRUE
Expands to "1".
#define FALSE
Expands to "0".
DBUS_PRIVATE_EXPORT dbus_bool_t _dbus_register_shutdown_func(DBusShutdownFunction function, void *data)
Register a cleanup function to be called exactly once the next time dbus_shutdown() is called.
Definition: dbus-memory.c:801
void(* DBusFreeFunction)(void *memory)
The type of a function which frees a block of memory.
Definition: dbus-memory.h:63
void dbus_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:692
#define dbus_new0(type, count)
Safe macro for using dbus_malloc0().
Definition: dbus-memory.h:58
#define DBUS_ERROR_NO_MEMORY
There was not enough memory to complete an operation.
#define DBUS_ERROR_INVALID_ARGS
Invalid arguments passed to a method call.
dbus_bool_t _dbus_string_append(DBusString *str, const char *buffer)
Appends a nul-terminated C-style string to a DBusString.
Definition: dbus-string.c:966
dbus_bool_t _dbus_string_init(DBusString *str)
Initializes a string.
Definition: dbus-string.c:182
void _dbus_string_free(DBusString *str)
Frees a string created by _dbus_string_init(), and fills it with the same contents as #_DBUS_STRING_I...
Definition: dbus-string.c:278
DBUS_PRIVATE_EXPORT dbus_bool_t _dbus_string_parse_uint(const DBusString *str, int start, unsigned long *value_return, int *end_return)
Parses an unsigned integer contained in a DBusString.
Definition: dbus-sysdeps.c:483
dbus_bool_t _dbus_user_info_fill(DBusUserInfo *info, const DBusString *username, DBusError *error)
Gets user info for the given username.
dbus_uid_t _dbus_geteuid(void)
Gets our effective UID.
dbus_bool_t _dbus_user_info_fill_uid(DBusUserInfo *info, dbus_uid_t uid, DBusError *error)
Gets user info for the given user ID.
unsigned long dbus_uid_t
A user ID.
Definition: dbus-sysdeps.h:137
#define DBUS_UID_UNSET
an invalid UID used to represent an uninitialized dbus_uid_t field
Definition: dbus-sysdeps.h:144
const char * _dbus_getenv(const char *varname)
Wrapper for getenv().
Definition: dbus-sysdeps.c:195
dbus_uid_t _dbus_getuid(void)
Gets our UID.
#define DBUS_UID_FORMAT
an appropriate printf format for dbus_uid_t
Definition: dbus-sysdeps.h:151
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:35
Object representing an exception.
Definition: dbus-errors.h:49
const char * message
public error message field
Definition: dbus-errors.h:51
Information about a UNIX group.
char * groupname
Group name.
size_t refcount
Reference count.
Information about a UNIX user.
dbus_uid_t uid
UID.
char * homedir
Home directory.
dbus_gid_t * group_ids
Groups IDs, including above primary group.
size_t refcount
Reference count.
char * username
Username.