D-Bus 1.15.12
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 * SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later
7 *
8 * Licensed under the Academic Free License version 2.1
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 *
24 */
25#include <config.h>
26#define DBUS_USERDB_INCLUDES_PRIVATE 1
27#include "dbus-userdb.h"
28#include "dbus-hash.h"
29#include "dbus-test.h"
30#include "dbus-internals.h"
31#include "dbus-protocol.h"
32#include "dbus-credentials.h"
33#include <string.h>
34
35/* It isn't obvious from its name, but this file is part of the Unix
36 * system-dependent part of libdbus. Windows has a parallel
37 * implementation of some of it in dbus-sysdeps-win.c. */
38#if defined(DBUS_WIN) || !defined(DBUS_UNIX)
39#error "This file only makes sense on Unix OSs"
40#endif
41
47static DBusUserInfo *
48_dbus_user_info_ref (DBusUserInfo *info)
49{
50 _dbus_assert (info->refcount > 0);
51 _dbus_assert (info->refcount < SIZE_MAX);
52 info->refcount++;
53 return info;
54}
55
63void
65{
66 if (info == NULL) /* hash table will pass NULL */
67 return;
68
69 _dbus_assert (info->refcount > 0);
70 _dbus_assert (info->refcount < SIZE_MAX);
71
72 if (--info->refcount > 0)
73 return;
74
76 dbus_free (info);
77}
78
86void
88{
89 if (info == NULL) /* hash table will pass NULL */
90 return;
91
92 _dbus_assert (info->refcount > 0);
93 _dbus_assert (info->refcount < SIZE_MAX);
94
95 if (--info->refcount > 0)
96 return;
97
99 dbus_free (info);
100}
101
107void
109{
110 dbus_free (info->group_ids);
111 dbus_free (info->username);
112 dbus_free (info->homedir);
113}
114
120void
125
134dbus_bool_t
136 unsigned long *num)
137{
138 int end;
139
140 if (_dbus_string_parse_uint (str, 0, num, &end) &&
141 end == _dbus_string_get_length (str))
142 return TRUE;
143 else
144 return FALSE;
145}
146
159const DBusUserInfo *
160_dbus_user_database_lookup (DBusUserDatabase *db,
161 dbus_uid_t uid,
162 const DBusString *username,
163 DBusError *error)
164{
165 DBusUserInfo *info;
166
167 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
168 _dbus_assert (uid != DBUS_UID_UNSET || username != NULL);
169
170 /* See if the username is really a number */
171 if (uid == DBUS_UID_UNSET)
172 {
173 unsigned long n;
174
175 if (_dbus_is_a_number (username, &n))
176 uid = n;
177 }
178
179 if (uid != DBUS_UID_UNSET)
180 info = _dbus_hash_table_lookup_uintptr (db->users, uid);
181 else
182 info = _dbus_hash_table_lookup_string (db->users_by_name, _dbus_string_get_const_data (username));
183
184 if (info)
185 {
186 _dbus_verbose ("Using cache for UID "DBUS_UID_FORMAT" information\n",
187 info->uid);
188 return info;
189 }
190 else
191 {
192 if (uid != DBUS_UID_UNSET)
193 _dbus_verbose ("No cache for UID "DBUS_UID_FORMAT"\n",
194 uid);
195 else
196 _dbus_verbose ("No cache for user \"%s\"\n",
197 _dbus_string_get_const_data (username));
198
199 info = dbus_new0 (DBusUserInfo, 1);
200 if (info == NULL)
201 {
203 return NULL;
204 }
205 info->refcount = 1;
206
207 if (uid != DBUS_UID_UNSET)
208 {
209 if (!_dbus_user_info_fill_uid (info, uid, error))
210 {
211 _DBUS_ASSERT_ERROR_IS_SET (error);
213 return NULL;
214 }
215 }
216 else
217 {
218 if (!_dbus_user_info_fill (info, username, error))
219 {
220 _DBUS_ASSERT_ERROR_IS_SET (error);
222 return NULL;
223 }
224 }
225
226 /* be sure we don't use these after here */
227 uid = DBUS_UID_UNSET;
228 username = NULL;
229
230 /* insert into hash */
231 if (_dbus_hash_table_insert_uintptr (db->users, info->uid, info))
232 {
233 _dbus_user_info_ref (info);
234 }
235 else
236 {
239 return NULL;
240 }
241
242 if (_dbus_hash_table_insert_string (db->users_by_name,
243 info->username,
244 info))
245 {
246 _dbus_user_info_ref (info);
247 }
248 else
249 {
250 _dbus_hash_table_remove_uintptr (db->users, info->uid);
253 return NULL;
254 }
255
257
258 /* Return a borrowed pointer to the DBusUserInfo owned by the
259 * hash tables */
260 return info;
261 }
262}
263
264/* Protected by _DBUS_LOCK_system_users */
265static dbus_bool_t database_locked = FALSE;
266static DBusUserDatabase *system_db = NULL;
267static DBusString process_username;
268static DBusString process_homedir;
269
270static void
271shutdown_system_db (void *data)
272{
273 if (system_db != NULL)
274 _dbus_user_database_unref (system_db);
275 system_db = NULL;
276 _dbus_string_free (&process_username);
277 _dbus_string_free (&process_homedir);
278}
279
280static dbus_bool_t
281init_system_db (void)
282{
283 _dbus_assert (database_locked);
284
285 if (system_db == NULL)
286 {
288 const DBusUserInfo *info;
289
290 system_db = _dbus_user_database_new ();
291 if (system_db == NULL)
292 return FALSE;
293
294 if (!_dbus_user_database_get_uid (system_db,
295 _dbus_getuid (),
296 &info,
297 &error))
298 {
299 _dbus_user_database_unref (system_db);
300 system_db = NULL;
301
303 {
304 dbus_error_free (&error);
305 return FALSE;
306 }
307 else
308 {
309 /* This really should not happen. */
310 _dbus_warn ("Could not get password database information for UID of current process: %s",
311 error.message);
312 dbus_error_free (&error);
313 return FALSE;
314 }
315 }
316
317 if (!_dbus_string_init (&process_username))
318 {
319 _dbus_user_database_unref (system_db);
320 system_db = NULL;
321 return FALSE;
322 }
323
324 if (!_dbus_string_init (&process_homedir))
325 {
326 _dbus_string_free (&process_username);
327 _dbus_user_database_unref (system_db);
328 system_db = NULL;
329 return FALSE;
330 }
331
332 if (!_dbus_string_append (&process_username,
333 info->username) ||
334 !_dbus_string_append (&process_homedir,
335 info->homedir) ||
336 !_dbus_register_shutdown_func (shutdown_system_db, NULL))
337 {
338 _dbus_string_free (&process_username);
339 _dbus_string_free (&process_homedir);
340 _dbus_user_database_unref (system_db);
341 system_db = NULL;
342 return FALSE;
343 }
344 }
345
346 return TRUE;
347}
348
352dbus_bool_t
354{
355 if (_DBUS_LOCK (system_users))
356 {
357 database_locked = TRUE;
358 return TRUE;
359 }
360 else
361 {
362 return FALSE;
363 }
364}
365
369void
371{
372 database_locked = FALSE;
373 _DBUS_UNLOCK (system_users);
374}
375
382DBusUserDatabase*
384{
385 _dbus_assert (database_locked);
386
387 init_system_db ();
388
389 return system_db;
390}
391
395void
397{
399 {
400 /* nothing to flush */
401 return;
402 }
403
404 if (system_db != NULL)
405 _dbus_user_database_flush (system_db);
406
408}
409
417dbus_bool_t
419{
421 return FALSE;
422
423 if (!init_system_db ())
424 {
426 return FALSE;
427 }
428 *username = &process_username;
430
431 return TRUE;
432}
433
441dbus_bool_t
443{
445 return FALSE;
446
447 if (!init_system_db ())
448 {
450 return FALSE;
451 }
452 *homedir = &process_homedir;
454
455 return TRUE;
456}
457
465dbus_bool_t
467 DBusString *homedir)
468{
469 DBusUserDatabase *db;
470 const DBusUserInfo *info;
471
472 if (uid == _dbus_getuid () && uid == _dbus_geteuid ())
473 {
474 const char *from_environment;
475
476 from_environment = _dbus_getenv ("HOME");
477
478 if (from_environment != NULL)
479 return _dbus_string_append (homedir, from_environment);
480 }
481
482 /* FIXME: this can't distinguish ENOMEM from other errors */
484 return FALSE;
485
487 if (db == NULL)
488 {
490 return FALSE;
491 }
492
493 if (!_dbus_user_database_get_uid (db, uid,
494 &info, NULL))
495 {
497 return FALSE;
498 }
499
500 if (!_dbus_string_append (homedir, info->homedir))
501 {
503 return FALSE;
504 }
505
507 return TRUE;
508}
509
524dbus_bool_t
526 const DBusString *username,
527 DBusCredentialsAddFlags flags,
528 DBusError *error)
529{
530 DBusUserDatabase *db;
531 const DBusUserInfo *info;
532 unsigned long uid = DBUS_UID_UNSET;
533
534 /* Fast-path for the common case: if the "username" is all-numeric,
535 * then it's a Unix uid. This is true regardless of whether that uid
536 * exists in NSS or /etc/passwd or equivalent. */
537 if (_dbus_is_a_number (username, &uid))
538 {
539 _DBUS_STATIC_ASSERT (sizeof (uid) == sizeof (dbus_uid_t));
540
541 if (_dbus_credentials_add_unix_uid (credentials, uid))
542 {
543 return TRUE;
544 }
545 else
546 {
547 _DBUS_SET_OOM (error);
548 return FALSE;
549 }
550 }
551
552 /* If we aren't allowed to look in NSS or /etc/passwd, fail now. */
553 if (!(flags & DBUS_CREDENTIALS_ADD_FLAGS_USER_DATABASE))
554 {
556 "Expected a numeric Unix uid");
557 return FALSE;
558 }
559
561 {
562 _DBUS_SET_OOM (error);
563 return FALSE;
564 }
565
567 if (db == NULL)
568 {
570 _DBUS_SET_OOM (error);
571 return FALSE;
572 }
573
574 if (!_dbus_user_database_get_username (db, username,
575 &info, error))
576 {
578 return FALSE;
579 }
580
581 if (!_dbus_credentials_add_unix_uid(credentials, info->uid))
582 {
584 _DBUS_SET_OOM (error);
585 return FALSE;
586 }
587
589 return TRUE;
590}
591
597DBusUserDatabase*
599{
600 DBusUserDatabase *db;
601
602 db = dbus_new0 (DBusUserDatabase, 1);
603 if (db == NULL)
604 return NULL;
605
606 db->refcount = 1;
607
610
611 if (db->users == NULL)
612 goto failed;
613
616
617 if (db->groups == NULL)
618 goto failed;
619
620 db->users_by_name = _dbus_hash_table_new (DBUS_HASH_STRING,
622 if (db->users_by_name == NULL)
623 goto failed;
624
625 db->groups_by_name = _dbus_hash_table_new (DBUS_HASH_STRING,
627 if (db->groups_by_name == NULL)
628 goto failed;
629
630 return db;
631
632 failed:
634 return NULL;
635}
636
640void
641_dbus_user_database_flush (DBusUserDatabase *db)
642{
643 _dbus_hash_table_remove_all(db->users_by_name);
644 _dbus_hash_table_remove_all(db->groups_by_name);
646 _dbus_hash_table_remove_all(db->groups);
647}
648
649#ifdef DBUS_ENABLE_EMBEDDED_TESTS
655DBusUserDatabase *
656_dbus_user_database_ref (DBusUserDatabase *db)
657{
658 _dbus_assert (db->refcount > 0);
659
660 db->refcount += 1;
661
662 return db;
663}
664#endif /* DBUS_ENABLE_EMBEDDED_TESTS */
665
670void
671_dbus_user_database_unref (DBusUserDatabase *db)
672{
673 _dbus_assert (db->refcount > 0);
674
675 db->refcount -= 1;
676 if (db->refcount == 0)
677 {
678 if (db->users)
679 _dbus_hash_table_unref (db->users);
680
681 if (db->groups)
682 _dbus_hash_table_unref (db->groups);
683
684 if (db->users_by_name)
685 _dbus_hash_table_unref (db->users_by_name);
686
687 if (db->groups_by_name)
688 _dbus_hash_table_unref (db->groups_by_name);
689
690 dbus_free (db);
691 }
692}
693
704dbus_bool_t
705_dbus_user_database_get_uid (DBusUserDatabase *db,
706 dbus_uid_t uid,
707 const DBusUserInfo **info,
708 DBusError *error)
709{
710 *info = _dbus_user_database_lookup (db, uid, NULL, error);
711 return *info != NULL;
712}
713
723dbus_bool_t
725 const DBusString *username,
726 const DBusUserInfo **info,
727 DBusError *error)
728{
729 *info = _dbus_user_database_lookup (db, DBUS_UID_UNSET, username, error);
730 return *info != NULL;
731}
732
735/* 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:64
dbus_bool_t dbus_error_has_name(const DBusError *error, const char *name)
Checks whether the error is set and has the given name.
void dbus_set_error(DBusError *error, const char *name, const char *format,...)
Assigns an error name and message to a DBusError.
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...
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:1243
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:1278
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:1163
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:368
DBusHashTable * _dbus_hash_table_new(DBusHashType type, DBusFreeFunction key_free_function, DBusFreeFunction value_free_function)
Constructs a new hash table.
Definition dbus-hash.c:292
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:1113
void _dbus_hash_table_remove_all(DBusHashTable *table)
Removed all entries from a hash table.
Definition dbus-hash.c:425
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:1353
@ 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.
dbus_bool_t _dbus_homedir_from_current_process(const DBusString **homedir)
Gets homedir of user owning current process.
#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.
#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.
void _dbus_user_database_unref(DBusUserDatabase *db)
Decrements refcount of user database.
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.
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.
void _dbus_user_database_flush_system(void)
Flushes the system global user database;.
void _dbus_group_info_unref(DBusGroupInfo *info)
Decrements the reference count.
Definition dbus-userdb.c:87
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.
void _dbus_user_info_unref(DBusUserInfo *info)
Decrements the reference count.
Definition dbus-userdb.c:64
dbus_bool_t _dbus_username_from_current_process(const DBusString **username)
Gets username of user owning current process.
void _dbus_user_info_free(DBusUserInfo *info)
Frees the members of info (but not info itself)
void _dbus_user_database_flush(DBusUserDatabase *db)
Flush all information out of the user database.
dbus_bool_t _dbus_homedir_from_uid(dbus_uid_t uid, DBusString *homedir)
Gets the home directory for the given user.
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).
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.
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.
DBusUserDatabase * _dbus_user_database_get_system(void)
Gets the system global user database; must be called with lock held (_dbus_user_database_lock_system(...
#define NULL
A null pointer, defined appropriately for C or C++.
Definition dbus-macros.h:51
#define TRUE
Expands to "1".
Definition dbus-macros.h:41
#define FALSE
Expands to "0".
Definition dbus-macros.h:44
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.
void(* DBusFreeFunction)(void *memory)
The type of a function which frees a block of memory.
Definition dbus-memory.h:65
void dbus_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
#define dbus_new0(type, count)
Safe macro for using dbus_malloc0().
Definition dbus-memory.h:60
#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.
dbus_bool_t _dbus_string_init(DBusString *str)
Initializes a string.
void _dbus_string_free(DBusString *str)
Frees a string created by _dbus_string_init(), and fills it with the same contents as _DBUS_STRING_IN...
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.
int _dbus_string_get_length(const DBusString *str)
Gets the length of a string (not including nul termination).
const char * _dbus_string_get_const_data(const DBusString *str)
Gets the raw character buffer from a const string.
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.
#define DBUS_UID_UNSET
an invalid UID used to represent an uninitialized dbus_uid_t field
const char * _dbus_getenv(const char *varname)
Wrapper for getenv().
dbus_uid_t _dbus_getuid(void)
Gets our UID.
#define DBUS_UID_FORMAT
an appropriate printf format for dbus_uid_t
Object representing an exception.
Definition dbus-errors.h:51
const char * message
public error message field
Definition dbus-errors.h:53
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.