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dbus-keyring.c

00001 /* -*- mode: C; c-file-style: "gnu" -*- */
00002 /* dbus-keyring.c Store secret cookies in your homedir
00003  *
00004  * Copyright (C) 2003  Red Hat Inc.
00005  *
00006  * Licensed under the Academic Free License version 1.2
00007  * 
00008  * This program is free software; you can redistribute it and/or modify
00009  * it under the terms of the GNU General Public License as published by
00010  * the Free Software Foundation; either version 2 of the License, or
00011  * (at your option) any later version.
00012  *
00013  * This program is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016  * GNU General Public License for more details.
00017  * 
00018  * You should have received a copy of the GNU General Public License
00019  * along with this program; if not, write to the Free Software
00020  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00021  *
00022  */
00023 
00024 #include "dbus-keyring.h"
00025 #include "dbus-userdb.h"
00026 #include <dbus/dbus-string.h>
00027 #include <dbus/dbus-list.h>
00028 #include <dbus/dbus-sysdeps.h>
00029 
00066 #define NEW_KEY_TIMEOUT_SECONDS     (60*5)
00067 
00072 #define EXPIRE_KEYS_TIMEOUT_SECONDS (NEW_KEY_TIMEOUT_SECONDS + (60*2))
00073 
00076 #define MAX_TIME_TRAVEL_SECONDS (60*5)
00077 
00082 #ifdef DBUS_BUILD_TESTS
00083 #define MAX_KEYS_IN_FILE 10
00084 #else
00085 #define MAX_KEYS_IN_FILE 256
00086 #endif
00087 
00091 typedef struct
00092 {
00093   dbus_int32_t id; 
00095   long creation_time; 
00100   DBusString secret; 
00102 } DBusKey;
00103 
00110 struct DBusKeyring
00111 {
00112   int refcount;             
00113   DBusString username;      
00114   DBusString directory;     
00115   DBusString filename;      
00116   DBusString filename_lock; 
00117   DBusKey *keys; 
00118   int n_keys;    
00119 };
00120 
00121 static DBusKeyring*
00122 _dbus_keyring_new (void)
00123 {
00124   DBusKeyring *keyring;
00125 
00126   keyring = dbus_new0 (DBusKeyring, 1);
00127   if (keyring == NULL)
00128     goto out_0;
00129   
00130   if (!_dbus_string_init (&keyring->directory))
00131     goto out_1;
00132 
00133   if (!_dbus_string_init (&keyring->filename))
00134     goto out_2;
00135 
00136   if (!_dbus_string_init (&keyring->filename_lock))
00137     goto out_3;
00138 
00139   if (!_dbus_string_init (&keyring->username))
00140     goto out_4;
00141   
00142   keyring->refcount = 1;
00143   keyring->keys = NULL;
00144   keyring->n_keys = 0;
00145 
00146   return keyring;
00147 
00148  out_4:
00149   _dbus_string_free (&keyring->filename_lock);
00150  out_3:
00151   _dbus_string_free (&keyring->filename);
00152  out_2:
00153   _dbus_string_free (&keyring->directory);
00154  out_1:
00155   dbus_free (keyring);
00156  out_0:
00157   return NULL;
00158 }
00159 
00160 static void
00161 free_keys (DBusKey *keys,
00162            int      n_keys)
00163 {
00164   int i;
00165 
00166   /* should be safe for args NULL, 0 */
00167   
00168   i = 0;
00169   while (i < n_keys)
00170     {
00171       _dbus_string_free (&keys[i].secret);
00172       ++i;
00173     }
00174 
00175   dbus_free (keys);
00176 }
00177 
00178 /* Our locking scheme is highly unreliable.  However, there is
00179  * unfortunately no reliable locking scheme in user home directories;
00180  * between bugs in Linux NFS, people using Tru64 or other total crap
00181  * NFS, AFS, random-file-system-of-the-week, and so forth, fcntl() in
00182  * homedirs simply generates tons of bug reports. This has been
00183  * learned through hard experience with GConf, unfortunately.
00184  *
00185  * This bad hack might work better for the kind of lock we have here,
00186  * which we don't expect to hold for any length of time.  Crashing
00187  * while we hold it should be unlikely, and timing out such that we
00188  * delete a stale lock should also be unlikely except when the
00189  * filesystem is running really slowly.  Stuff might break in corner
00190  * cases but as long as it's not a security-level breakage it should
00191  * be OK.
00192  */
00193 
00195 #define MAX_LOCK_TIMEOUTS 32
00196 
00197 #define LOCK_TIMEOUT_MILLISECONDS 250
00198 
00199 static dbus_bool_t
00200 _dbus_keyring_lock (DBusKeyring *keyring)
00201 {
00202   int n_timeouts;
00203   
00204   n_timeouts = 0;
00205   while (n_timeouts < MAX_LOCK_TIMEOUTS)
00206     {
00207       DBusError error;
00208 
00209       dbus_error_init (&error);
00210       if (_dbus_create_file_exclusively (&keyring->filename_lock,
00211                                          &error))
00212         break;
00213 
00214       _dbus_verbose ("Did not get lock file, sleeping %d milliseconds (%s)\n",
00215                      LOCK_TIMEOUT_MILLISECONDS, error.message);
00216       dbus_error_free (&error);
00217 
00218       _dbus_sleep_milliseconds (LOCK_TIMEOUT_MILLISECONDS);
00219       
00220       ++n_timeouts;
00221     }
00222 
00223   if (n_timeouts == MAX_LOCK_TIMEOUTS)
00224     {
00225       DBusError error;
00226       
00227       _dbus_verbose ("Lock file timed out %d times, assuming stale\n",
00228                      n_timeouts);
00229 
00230       dbus_error_init (&error);
00231 
00232       if (!_dbus_delete_file (&keyring->filename_lock, &error))
00233         {
00234           _dbus_verbose ("Couldn't delete old lock file: %s\n",
00235                          error.message);
00236           dbus_error_free (&error);
00237           return FALSE;
00238         }
00239 
00240       if (!_dbus_create_file_exclusively (&keyring->filename_lock,
00241                                           &error))
00242         {
00243           _dbus_verbose ("Couldn't create lock file after deleting stale one: %s\n",
00244                          error.message);
00245           dbus_error_free (&error);
00246           return FALSE;
00247         }
00248     }
00249   
00250   return TRUE;
00251 }
00252 
00253 static void
00254 _dbus_keyring_unlock (DBusKeyring *keyring)
00255 {
00256   DBusError error;
00257   dbus_error_init (&error);
00258   if (!_dbus_delete_file (&keyring->filename_lock, &error))
00259     {
00260       _dbus_warn ("Failed to delete lock file: %s\n",
00261                   error.message);
00262       dbus_error_free (&error);
00263     }
00264 }
00265 
00266 static DBusKey*
00267 find_key_by_id (DBusKey *keys,
00268                 int      n_keys,
00269                 int      id)
00270 {
00271   int i;
00272 
00273   i = 0;
00274   while (i < n_keys)
00275     {
00276       if (keys[i].id == id)
00277         return &keys[i];
00278       
00279       ++i;
00280     }
00281 
00282   return NULL;
00283 }
00284 
00285 static dbus_bool_t
00286 add_new_key (DBusKey  **keys_p,
00287              int       *n_keys_p,
00288              DBusError *error)
00289 {
00290   DBusKey *new;
00291   DBusString bytes;
00292   int id;
00293   unsigned long timestamp;
00294   const unsigned char *s;
00295   dbus_bool_t retval;
00296   DBusKey *keys;
00297   int n_keys;
00298 
00299   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00300   
00301   if (!_dbus_string_init (&bytes))
00302     {
00303       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00304       return FALSE;
00305     }
00306 
00307   keys = *keys_p;
00308   n_keys = *n_keys_p;
00309   retval = FALSE;
00310       
00311   /* Generate an integer ID and then the actual key. */
00312  retry:
00313       
00314   if (!_dbus_generate_random_bytes (&bytes, 4))
00315     {
00316       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00317       goto out;
00318     }
00319 
00320   s = (const unsigned char*) _dbus_string_get_const_data (&bytes);
00321       
00322   id = s[0] | (s[1] << 8) | (s[2] << 16) | (s[3] << 24);
00323   if (id < 0)
00324     id = - id;
00325   _dbus_assert (id >= 0);
00326 
00327   if (find_key_by_id (keys, n_keys, id) != NULL)
00328     {
00329       _dbus_string_set_length (&bytes, 0);
00330       _dbus_verbose ("Key ID %d already existed, trying another one\n",
00331                      id);
00332       goto retry;
00333     }
00334 
00335   _dbus_verbose ("Creating key with ID %d\n", id);
00336       
00337 #define KEY_LENGTH_BYTES 24
00338   _dbus_string_set_length (&bytes, 0);
00339   if (!_dbus_generate_random_bytes (&bytes, KEY_LENGTH_BYTES))
00340     {
00341       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00342       goto out;
00343     }
00344 
00345   new = dbus_realloc (keys, sizeof (DBusKey) * (n_keys + 1));
00346   if (new == NULL)
00347     {
00348       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00349       goto out;
00350     }
00351 
00352   keys = new;
00353   *keys_p = keys; /* otherwise *keys_p ends up invalid */
00354   n_keys += 1;
00355 
00356   if (!_dbus_string_init (&keys[n_keys-1].secret))
00357     {
00358       n_keys -= 1; /* we don't want to free the one we didn't init */
00359       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00360       goto out;
00361     }
00362 
00363   _dbus_get_current_time (&timestamp, NULL);
00364       
00365   keys[n_keys-1].id = id;
00366   keys[n_keys-1].creation_time = timestamp;
00367   if (!_dbus_string_move (&bytes, 0,
00368                           &keys[n_keys-1].secret,
00369                           0))
00370     {
00371       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00372       _dbus_string_free (&keys[n_keys-1].secret);
00373       n_keys -= 1;
00374       goto out;
00375     }
00376   
00377   retval = TRUE;
00378   
00379  out:
00380   *n_keys_p = n_keys;
00381   
00382   _dbus_string_free (&bytes);
00383   return retval;
00384 }
00385 
00400 static dbus_bool_t
00401 _dbus_keyring_reload (DBusKeyring *keyring,
00402                       dbus_bool_t  add_new,
00403                       DBusError   *error)
00404 {
00405   DBusString contents;
00406   DBusString line;
00407   dbus_bool_t retval;
00408   dbus_bool_t have_lock;
00409   DBusKey *keys;
00410   int n_keys;
00411   int i;
00412   long now;
00413   DBusError tmp_error;
00414 
00415   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00416   
00417   if (!_dbus_string_init (&contents))
00418     {
00419       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00420       return FALSE;
00421     }
00422 
00423   if (!_dbus_string_init (&line))
00424     {
00425       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00426       _dbus_string_free (&contents);
00427       return FALSE;
00428     }
00429 
00430   keys = NULL;
00431   n_keys = 0;
00432   retval = FALSE;
00433   have_lock = FALSE;
00434 
00435   _dbus_get_current_time (&now, NULL);
00436   
00437   if (add_new)
00438     {
00439       if (!_dbus_keyring_lock (keyring))
00440         {
00441           dbus_set_error (error, DBUS_ERROR_FAILED,
00442                           "Could not lock keyring file to add to it");
00443           goto out;
00444         }
00445 
00446       have_lock = TRUE;
00447     }
00448 
00449   dbus_error_init (&tmp_error);
00450   if (!_dbus_file_get_contents (&contents, 
00451                                 &keyring->filename,
00452                                 &tmp_error))
00453     {
00454       _dbus_verbose ("Failed to load keyring file: %s\n",
00455                      tmp_error.message);
00456       /* continue with empty keyring file, so we recreate it */
00457       dbus_error_free (&tmp_error);
00458     }
00459 
00460   if (!_dbus_string_validate_ascii (&contents, 0,
00461                                     _dbus_string_get_length (&contents)))
00462     {
00463       _dbus_warn ("Secret keyring file contains non-ASCII! Ignoring existing contents\n");
00464       _dbus_string_set_length (&contents, 0);
00465     }
00466 
00467   /* FIXME this is badly inefficient for large keyring files
00468    * (not that large keyring files exist outside of test suites)
00469    */
00470   while (_dbus_string_pop_line (&contents, &line))
00471     {
00472       int next;
00473       long val;
00474       int id;
00475       long timestamp;
00476       int len;
00477       DBusKey *new;
00478 
00479       /* Don't load more than the max. */
00480       if (n_keys >= (add_new ? MAX_KEYS_IN_FILE : MAX_KEYS_IN_FILE - 1))
00481         break;
00482       
00483       next = 0;
00484       if (!_dbus_string_parse_int (&line, 0, &val, &next))
00485         {
00486           _dbus_verbose ("could not parse secret key ID at start of line\n");
00487           continue;
00488         }
00489 
00490       if (val > _DBUS_INT_MAX || val < 0)
00491         {
00492           _dbus_verbose ("invalid secret key ID at start of line\n");
00493           continue;
00494         }
00495       
00496       id = val;
00497 
00498       _dbus_string_skip_blank (&line, next, &next);
00499       
00500       if (!_dbus_string_parse_int (&line, next, &timestamp, &next))
00501         {
00502           _dbus_verbose ("could not parse secret key timestamp\n");
00503           continue;
00504         }
00505 
00506       if (timestamp < 0 ||
00507           (now + MAX_TIME_TRAVEL_SECONDS) < timestamp ||
00508           (now - EXPIRE_KEYS_TIMEOUT_SECONDS) > timestamp)
00509         {
00510           _dbus_verbose ("dropping/ignoring %ld-seconds old key with timestamp %ld as current time is %ld\n",
00511                          now - timestamp, timestamp, now);
00512           continue;
00513         }
00514       
00515       _dbus_string_skip_blank (&line, next, &next);
00516 
00517       len = _dbus_string_get_length (&line);
00518 
00519       if ((len - next) == 0)
00520         {
00521           _dbus_verbose ("no secret key after ID and timestamp\n");
00522           continue;
00523         }
00524       
00525       /* We have all three parts */
00526       new = dbus_realloc (keys, sizeof (DBusKey) * (n_keys + 1));
00527       if (new == NULL)
00528         {
00529           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00530           goto out;
00531         }
00532 
00533       keys = new;
00534       n_keys += 1;
00535 
00536       if (!_dbus_string_init (&keys[n_keys-1].secret))
00537         {
00538           n_keys -= 1; /* we don't want to free the one we didn't init */
00539           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00540           goto out;
00541         }
00542       
00543       keys[n_keys-1].id = id;
00544       keys[n_keys-1].creation_time = timestamp;
00545       if (!_dbus_string_hex_decode (&line, next,
00546                                     &keys[n_keys-1].secret,
00547                                     0))
00548         {
00549           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00550           goto out;
00551         }
00552     }
00553 
00554   _dbus_verbose ("Successfully loaded %d existing keys\n",
00555                  n_keys);
00556 
00557   if (add_new)
00558     {
00559       if (!add_new_key (&keys, &n_keys, error))
00560         {
00561           _dbus_verbose ("Failed to generate new key: %s\n",
00562                          error ? "(unknown)" : error->message);
00563           goto out;
00564         }
00565 
00566       _dbus_string_set_length (&contents, 0);
00567 
00568       i = 0;
00569       while (i < n_keys)
00570         {
00571           if (!_dbus_string_append_int (&contents,
00572                                         keys[i].id))
00573             goto nomem;
00574 
00575           if (!_dbus_string_append_byte (&contents, ' '))
00576             goto nomem;
00577 
00578           if (!_dbus_string_append_int (&contents,
00579                                         keys[i].creation_time))
00580             goto nomem;
00581 
00582           if (!_dbus_string_append_byte (&contents, ' '))
00583             goto nomem;
00584 
00585           if (!_dbus_string_hex_encode (&keys[i].secret, 0,
00586                                         &contents,
00587                                         _dbus_string_get_length (&contents)))
00588             goto nomem;
00589 
00590           if (!_dbus_string_append_byte (&contents, '\n'))
00591             goto nomem;          
00592           
00593           ++i;
00594           continue;
00595 
00596         nomem:
00597           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00598           goto out;
00599         }
00600       
00601       if (!_dbus_string_save_to_file (&contents, &keyring->filename,
00602                                       error))
00603         goto out;
00604     }
00605 
00606   if (keyring->keys)
00607     free_keys (keyring->keys, keyring->n_keys);
00608   keyring->keys = keys;
00609   keyring->n_keys = n_keys;
00610   keys = NULL;
00611   n_keys = 0;
00612   
00613   retval = TRUE;  
00614   
00615  out:
00616   if (have_lock)
00617     _dbus_keyring_unlock (keyring);
00618   
00619   if (! ((retval == TRUE && (error == NULL || error->name == NULL)) ||
00620          (retval == FALSE && (error == NULL || error->name != NULL))))
00621     {
00622       if (error && error->name)
00623         _dbus_verbose ("error is %s: %s\n", error->name, error->message);
00624       _dbus_warn ("returning %d but error pointer %p name %s\n",
00625                   retval, error, error->name ? error->name : "(none)");
00626       _dbus_assert_not_reached ("didn't handle errors properly");
00627     }
00628   
00629   if (keys != NULL)
00630     {
00631       i = 0;
00632       while (i < n_keys)
00633         {
00634           _dbus_string_zero (&keys[i].secret);
00635           _dbus_string_free (&keys[i].secret);
00636           ++i;
00637         }
00638 
00639       dbus_free (keys);
00640     }
00641   
00642   _dbus_string_free (&contents);
00643   _dbus_string_free (&line);
00644 
00645   return retval;
00646 }
00647  /* end of internals */
00649 
00661 void
00662 _dbus_keyring_ref (DBusKeyring *keyring)
00663 {
00664   keyring->refcount += 1;
00665 }
00666 
00673 void
00674 _dbus_keyring_unref (DBusKeyring *keyring)
00675 {
00676   keyring->refcount -= 1;
00677 
00678   if (keyring->refcount == 0)
00679     {
00680       _dbus_string_free (&keyring->username);
00681       _dbus_string_free (&keyring->filename);
00682       _dbus_string_free (&keyring->filename_lock);
00683       _dbus_string_free (&keyring->directory);
00684       free_keys (keyring->keys, keyring->n_keys);
00685       dbus_free (keyring);      
00686     }
00687 }
00688 
00699 DBusKeyring*
00700 _dbus_keyring_new_homedir (const DBusString *username,
00701                            const DBusString *context,
00702                            DBusError        *error)
00703 {
00704   DBusString homedir;
00705   DBusKeyring *keyring;
00706   dbus_bool_t error_set;
00707   DBusString dotdir;
00708   DBusError tmp_error;
00709 
00710   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00711   
00712   keyring = NULL;
00713   error_set = FALSE;
00714   
00715   if (!_dbus_string_init (&homedir))
00716     {
00717       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00718       return FALSE;
00719     }
00720 
00721   _dbus_string_init_const (&dotdir, ".dbus-keyrings");
00722   
00723   if (username == NULL)
00724     {
00725       const DBusString *const_homedir;
00726 
00727       if (!_dbus_username_from_current_process (&username) ||
00728           !_dbus_homedir_from_current_process (&const_homedir))
00729         goto failed;
00730 
00731       if (!_dbus_string_copy (const_homedir, 0,
00732                               &homedir, 0))
00733         goto failed;
00734     }
00735   else
00736     {
00737       if (!_dbus_homedir_from_username (username, &homedir))
00738         goto failed;
00739     }
00740 
00741 #ifdef DBUS_BUILD_TESTS
00742  {
00743    const char *override;
00744 
00745    override = _dbus_getenv ("DBUS_TEST_HOMEDIR");
00746    if (override != NULL && *override != '\0')
00747      {
00748        _dbus_string_set_length (&homedir, 0);
00749        if (!_dbus_string_append (&homedir, override))
00750          _dbus_assert_not_reached ("no memory");
00751 
00752        _dbus_verbose ("Using fake homedir for testing: %s\n",
00753                       _dbus_string_get_const_data (&homedir));
00754      }
00755    else
00756      {
00757        static dbus_bool_t already_warned = FALSE;
00758        if (!already_warned)
00759          {
00760            _dbus_warn ("Using your real home directory for testing, set DBUS_TEST_HOMEDIR to avoid\n");
00761            already_warned = TRUE;
00762          }
00763      }
00764  }
00765 #endif
00766   
00767   _dbus_assert (username != NULL);    
00768   
00769   keyring = _dbus_keyring_new ();
00770   if (keyring == NULL)
00771     goto failed;
00772 
00773   /* should have been validated already, but paranoia check here */
00774   if (!_dbus_keyring_validate_context (context))
00775     {
00776       error_set = TRUE;
00777       dbus_set_error_const (error,
00778                             DBUS_ERROR_FAILED,
00779                             "Invalid context in keyring creation");
00780       goto failed;
00781     }
00782 
00783   if (!_dbus_string_copy (username, 0,
00784                           &keyring->username, 0))
00785     goto failed;
00786   
00787   if (!_dbus_string_copy (&homedir, 0,
00788                           &keyring->directory, 0))
00789     goto failed;
00790   
00791   if (!_dbus_concat_dir_and_file (&keyring->directory,
00792                                   &dotdir))
00793     goto failed;
00794 
00795   if (!_dbus_string_copy (&keyring->directory, 0,
00796                           &keyring->filename, 0))
00797     goto failed;
00798 
00799   if (!_dbus_concat_dir_and_file (&keyring->filename,
00800                                   context))
00801     goto failed;
00802 
00803   if (!_dbus_string_copy (&keyring->filename, 0,
00804                           &keyring->filename_lock, 0))
00805     goto failed;
00806 
00807   if (!_dbus_string_append (&keyring->filename_lock, ".lock"))
00808     goto failed;
00809 
00810   dbus_error_init (&tmp_error);
00811   if (!_dbus_keyring_reload (keyring, FALSE, &tmp_error))
00812     {
00813       _dbus_verbose ("didn't load an existing keyring: %s\n",
00814                      tmp_error.message);
00815       dbus_error_free (&tmp_error);
00816     }
00817   
00818   /* We don't fail fatally if we can't create the directory,
00819    * but the keyring will probably always be empty
00820    * unless someone else manages to create it
00821    */
00822   dbus_error_init (&tmp_error);
00823   if (!_dbus_create_directory (&keyring->directory,
00824                                &tmp_error))
00825     {
00826       _dbus_verbose ("Creating keyring directory: %s\n",
00827                      tmp_error.message);
00828       dbus_error_free (&tmp_error);
00829     }
00830 
00831   _dbus_string_free (&homedir);
00832   
00833   return keyring;
00834   
00835  failed:
00836   if (!error_set)
00837     dbus_set_error_const (error,
00838                           DBUS_ERROR_NO_MEMORY,
00839                           NULL);
00840   if (keyring)
00841     _dbus_keyring_unref (keyring);
00842   _dbus_string_free (&homedir);
00843   return FALSE;
00844 
00845 }
00846 
00859 dbus_bool_t
00860 _dbus_keyring_validate_context (const DBusString *context)
00861 {
00862   if (_dbus_string_get_length (context) == 0)
00863     {
00864       _dbus_verbose ("context is zero-length\n");
00865       return FALSE;
00866     }
00867 
00868   if (!_dbus_string_validate_ascii (context, 0,
00869                                     _dbus_string_get_length (context)))
00870     {
00871       _dbus_verbose ("context not valid ascii\n");
00872       return FALSE;
00873     }
00874   
00875   /* no directory separators */  
00876   if (_dbus_string_find (context, 0, "/", NULL))
00877     {
00878       _dbus_verbose ("context contains a slash\n");
00879       return FALSE;
00880     }
00881 
00882   if (_dbus_string_find (context, 0, "\\", NULL))
00883     {
00884       _dbus_verbose ("context contains a backslash\n");
00885       return FALSE;
00886     }
00887 
00888   /* prevent attempts to use dotfiles or ".." or ".lock"
00889    * all of which might allow some kind of attack
00890    */
00891   if (_dbus_string_find (context, 0, ".", NULL))
00892     {
00893       _dbus_verbose ("context contains a dot\n");
00894       return FALSE;
00895     }
00896 
00897   /* no spaces/tabs, those are used for separators in the protocol */
00898   if (_dbus_string_find_blank (context, 0, NULL))
00899     {
00900       _dbus_verbose ("context contains a blank\n");
00901       return FALSE;
00902     }
00903 
00904   if (_dbus_string_find (context, 0, "\n", NULL))
00905     {
00906       _dbus_verbose ("context contains a newline\n");
00907       return FALSE;
00908     }
00909 
00910   if (_dbus_string_find (context, 0, "\r", NULL))
00911     {
00912       _dbus_verbose ("context contains a carriage return\n");
00913       return FALSE;
00914     }
00915   
00916   return TRUE;
00917 }
00918 
00919 static DBusKey*
00920 find_recent_key (DBusKeyring *keyring)
00921 {
00922   int i;
00923   long tv_sec, tv_usec;
00924 
00925   _dbus_get_current_time (&tv_sec, &tv_usec);
00926   
00927   i = 0;
00928   while (i < keyring->n_keys)
00929     {
00930       DBusKey *key = &keyring->keys[i];
00931 
00932       _dbus_verbose ("Key %d is %ld seconds old\n",
00933                      i, tv_sec - key->creation_time);
00934       
00935       if ((tv_sec - NEW_KEY_TIMEOUT_SECONDS) < key->creation_time)
00936         return key;
00937       
00938       ++i;
00939     }
00940 
00941   return NULL;
00942 }
00943 
00955 int
00956 _dbus_keyring_get_best_key (DBusKeyring  *keyring,
00957                             DBusError    *error)
00958 {
00959   DBusKey *key;
00960 
00961   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00962   
00963   key = find_recent_key (keyring);
00964   if (key)
00965     return key->id;
00966 
00967   /* All our keys are too old, or we've never loaded the
00968    * keyring. Create a new one.
00969    */
00970   if (!_dbus_keyring_reload (keyring, TRUE,
00971                              error))
00972     return -1;
00973 
00974   key = find_recent_key (keyring);
00975   if (key)
00976     return key->id;
00977   else
00978     {
00979       dbus_set_error_const (error,
00980                             DBUS_ERROR_FAILED,
00981                             "No recent-enough key found in keyring, and unable to create a new key");
00982       return -1;
00983     }
00984 }
00985 
00994 dbus_bool_t
00995 _dbus_keyring_is_for_user (DBusKeyring       *keyring,
00996                            const DBusString  *username)
00997 {
00998   return _dbus_string_equal (&keyring->username,
00999                              username);
01000 }
01001 
01013 dbus_bool_t
01014 _dbus_keyring_get_hex_key (DBusKeyring       *keyring,
01015                            int                key_id,
01016                            DBusString        *hex_key)
01017 {
01018   DBusKey *key;
01019 
01020   key = find_key_by_id (keyring->keys,
01021                         keyring->n_keys,
01022                         key_id);
01023   if (key == NULL)
01024     return TRUE; /* had enough memory, so TRUE */
01025 
01026   return _dbus_string_hex_encode (&key->secret, 0,
01027                                   hex_key,
01028                                   _dbus_string_get_length (hex_key));
01029 }
01030  /* end of exposed API */
01032 
01033 #ifdef DBUS_BUILD_TESTS
01034 #include "dbus-test.h"
01035 #include <stdio.h>
01036 
01037 dbus_bool_t
01038 _dbus_keyring_test (void)
01039 {
01040   DBusString context;
01041   DBusKeyring *ring1;
01042   DBusKeyring *ring2;
01043   int id;
01044   DBusError error;
01045   int i;
01046 
01047   ring1 = NULL;
01048   ring2 = NULL;
01049   
01050   /* Context validation */
01051   
01052   _dbus_string_init_const (&context, "foo");
01053   _dbus_assert (_dbus_keyring_validate_context (&context));
01054   _dbus_string_init_const (&context, "org_freedesktop_blah");
01055   _dbus_assert (_dbus_keyring_validate_context (&context));
01056   
01057   _dbus_string_init_const (&context, "");
01058   _dbus_assert (!_dbus_keyring_validate_context (&context));
01059   _dbus_string_init_const (&context, ".foo");
01060   _dbus_assert (!_dbus_keyring_validate_context (&context));
01061   _dbus_string_init_const (&context, "bar.foo");
01062   _dbus_assert (!_dbus_keyring_validate_context (&context));
01063   _dbus_string_init_const (&context, "bar/foo");
01064   _dbus_assert (!_dbus_keyring_validate_context (&context));
01065   _dbus_string_init_const (&context, "bar\\foo");
01066   _dbus_assert (!_dbus_keyring_validate_context (&context));
01067   _dbus_string_init_const (&context, "foo\xfa\xf0");
01068   _dbus_assert (!_dbus_keyring_validate_context (&context));
01069   _dbus_string_init_const (&context, "foo\x80");
01070   _dbus_assert (!_dbus_keyring_validate_context (&context));
01071   _dbus_string_init_const (&context, "foo\x7f");
01072   _dbus_assert (_dbus_keyring_validate_context (&context));
01073   _dbus_string_init_const (&context, "foo bar");
01074   _dbus_assert (!_dbus_keyring_validate_context (&context));
01075   
01076   if (!_dbus_string_init (&context))
01077     _dbus_assert_not_reached ("no memory");
01078   if (!_dbus_string_append_byte (&context, '\0'))
01079     _dbus_assert_not_reached ("no memory");
01080   _dbus_assert (!_dbus_keyring_validate_context (&context));
01081   _dbus_string_free (&context);
01082 
01083   /* Now verify that if we create a key in keyring 1,
01084    * it is properly loaded in keyring 2
01085    */
01086 
01087   _dbus_string_init_const (&context, "org_freedesktop_dbus_testsuite");
01088   dbus_error_init (&error);
01089   ring1 = _dbus_keyring_new_homedir (NULL, &context,
01090                                      &error);
01091   _dbus_assert (ring1);
01092   _dbus_assert (error.name == NULL);
01093 
01094   id = _dbus_keyring_get_best_key (ring1, &error);
01095   if (id < 0)
01096     {
01097       fprintf (stderr, "Could not load keyring: %s\n", error.message);
01098       dbus_error_free (&error);
01099       goto failure;
01100     }
01101 
01102   ring2 = _dbus_keyring_new_homedir (NULL, &context, &error);
01103   _dbus_assert (ring2);
01104   _dbus_assert (error.name == NULL);
01105   
01106   if (ring1->n_keys != ring2->n_keys)
01107     {
01108       fprintf (stderr, "Different number of keys in keyrings\n");
01109       goto failure;
01110     }
01111 
01112   /* We guarantee we load and save keeping keys in a fixed
01113    * order
01114    */
01115   i = 0;
01116   while (i < ring1->n_keys)
01117     {
01118       if (ring1->keys[i].id != ring2->keys[i].id)
01119         {
01120           fprintf (stderr, "Keyring 1 has first key ID %d and keyring 2 has %d\n",
01121                    ring1->keys[i].id, ring2->keys[i].id);
01122           goto failure;
01123         }      
01124 
01125       if (ring1->keys[i].creation_time != ring2->keys[i].creation_time)
01126         {
01127           fprintf (stderr, "Keyring 1 has first key time %ld and keyring 2 has %ld\n",
01128                    ring1->keys[i].creation_time, ring2->keys[i].creation_time);
01129           goto failure;
01130         }
01131 
01132       if (!_dbus_string_equal (&ring1->keys[i].secret,
01133                                &ring2->keys[i].secret))
01134         {
01135           fprintf (stderr, "Keyrings 1 and 2 have different secrets for same ID/timestamp\n");
01136           goto failure;
01137         }
01138       
01139       ++i;
01140     }
01141 
01142   printf (" %d keys in test\n", ring1->n_keys);
01143 
01144   /* Test ref/unref */
01145   _dbus_keyring_ref (ring1);
01146   _dbus_keyring_ref (ring2);
01147   _dbus_keyring_unref (ring1);
01148   _dbus_keyring_unref (ring2);
01149 
01150 
01151   /* really unref */
01152   _dbus_keyring_unref (ring1);
01153   _dbus_keyring_unref (ring2);
01154   
01155   return TRUE;
01156 
01157  failure:
01158   if (ring1)
01159     _dbus_keyring_unref (ring1);
01160   if (ring2)
01161     _dbus_keyring_unref (ring2);
01162 
01163   return FALSE;
01164 }
01165 
01166 #endif /* DBUS_BUILD_TESTS */
01167      

Generated on Tue Feb 10 18:14:03 2004 for D-BUS by doxygen 1.3.5