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 */
44void
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 */
60void
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 */
75void
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 */
88void
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 */
102dbus_bool_t
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 */
127DBusUserInfo*
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
222static dbus_bool_t database_locked = FALSE;
223static DBusUserDatabase *system_db = NULL;
224static DBusString process_username;
225static DBusString process_homedir;
226
227static void
228shutdown_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
237static dbus_bool_t
238init_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 */
309void
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 */
319void
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 */
332DBusUserDatabase*
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 */
345void
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 */
363dbus_bool_t
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 */
385dbus_bool_t
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 */
407dbus_bool_t
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 */
446dbus_bool_t
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 */
492dbus_bool_t
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 */
530DBusUserDatabase*
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 */
573void
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 */
588DBusUserDatabase *
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 */
603void
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 */
637dbus_bool_t
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 */
656dbus_bool_t
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