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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 2.0
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       int end;
00478       DBusKey *new;
00479 
00480       /* Don't load more than the max. */
00481       if (n_keys >= (add_new ? MAX_KEYS_IN_FILE : MAX_KEYS_IN_FILE - 1))
00482         break;
00483       
00484       next = 0;
00485       if (!_dbus_string_parse_int (&line, 0, &val, &next))
00486         {
00487           _dbus_verbose ("could not parse secret key ID at start of line\n");
00488           continue;
00489         }
00490 
00491       if (val > _DBUS_INT_MAX || val < 0)
00492         {
00493           _dbus_verbose ("invalid secret key ID at start of line\n");
00494           continue;
00495         }
00496       
00497       id = val;
00498 
00499       _dbus_string_skip_blank (&line, next, &next);
00500       
00501       if (!_dbus_string_parse_int (&line, next, &timestamp, &next))
00502         {
00503           _dbus_verbose ("could not parse secret key timestamp\n");
00504           continue;
00505         }
00506 
00507       if (timestamp < 0 ||
00508           (now + MAX_TIME_TRAVEL_SECONDS) < timestamp ||
00509           (now - EXPIRE_KEYS_TIMEOUT_SECONDS) > timestamp)
00510         {
00511           _dbus_verbose ("dropping/ignoring %ld-seconds old key with timestamp %ld as current time is %ld\n",
00512                          now - timestamp, timestamp, now);
00513           continue;
00514         }
00515       
00516       _dbus_string_skip_blank (&line, next, &next);
00517 
00518       len = _dbus_string_get_length (&line);
00519 
00520       if ((len - next) == 0)
00521         {
00522           _dbus_verbose ("no secret key after ID and timestamp\n");
00523           continue;
00524         }
00525       
00526       /* We have all three parts */
00527       new = dbus_realloc (keys, sizeof (DBusKey) * (n_keys + 1));
00528       if (new == NULL)
00529         {
00530           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00531           goto out;
00532         }
00533 
00534       keys = new;
00535       n_keys += 1;
00536 
00537       if (!_dbus_string_init (&keys[n_keys-1].secret))
00538         {
00539           n_keys -= 1; /* we don't want to free the one we didn't init */
00540           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00541           goto out;
00542         }
00543       
00544       keys[n_keys-1].id = id;
00545       keys[n_keys-1].creation_time = timestamp;
00546       if (!_dbus_string_hex_decode (&line, next, &end,
00547                                     &keys[n_keys-1].secret, 0))
00548         {
00549           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00550           goto out;
00551         }
00552 
00553       if (_dbus_string_get_length (&line) != end)
00554         {
00555           _dbus_verbose ("invalid hex encoding in keyring file\n");
00556           _dbus_string_free (&keys[n_keys - 1].secret);
00557           n_keys -= 1;
00558           continue;
00559         }
00560     }
00561 
00562   _dbus_verbose ("Successfully loaded %d existing keys\n",
00563                  n_keys);
00564 
00565   if (add_new)
00566     {
00567       if (!add_new_key (&keys, &n_keys, error))
00568         {
00569           _dbus_verbose ("Failed to generate new key: %s\n",
00570                          error ? "(unknown)" : error->message);
00571           goto out;
00572         }
00573 
00574       _dbus_string_set_length (&contents, 0);
00575 
00576       i = 0;
00577       while (i < n_keys)
00578         {
00579           if (!_dbus_string_append_int (&contents,
00580                                         keys[i].id))
00581             goto nomem;
00582 
00583           if (!_dbus_string_append_byte (&contents, ' '))
00584             goto nomem;
00585 
00586           if (!_dbus_string_append_int (&contents,
00587                                         keys[i].creation_time))
00588             goto nomem;
00589 
00590           if (!_dbus_string_append_byte (&contents, ' '))
00591             goto nomem;
00592 
00593           if (!_dbus_string_hex_encode (&keys[i].secret, 0,
00594                                         &contents,
00595                                         _dbus_string_get_length (&contents)))
00596             goto nomem;
00597 
00598           if (!_dbus_string_append_byte (&contents, '\n'))
00599             goto nomem;          
00600           
00601           ++i;
00602           continue;
00603 
00604         nomem:
00605           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00606           goto out;
00607         }
00608       
00609       if (!_dbus_string_save_to_file (&contents, &keyring->filename,
00610                                       error))
00611         goto out;
00612     }
00613 
00614   if (keyring->keys)
00615     free_keys (keyring->keys, keyring->n_keys);
00616   keyring->keys = keys;
00617   keyring->n_keys = n_keys;
00618   keys = NULL;
00619   n_keys = 0;
00620   
00621   retval = TRUE;  
00622   
00623  out:
00624   if (have_lock)
00625     _dbus_keyring_unlock (keyring);
00626   
00627   if (! ((retval == TRUE && (error == NULL || error->name == NULL)) ||
00628          (retval == FALSE && (error == NULL || error->name != NULL))))
00629     {
00630       if (error && error->name)
00631         _dbus_verbose ("error is %s: %s\n", error->name, error->message);
00632       _dbus_warn ("returning %d but error pointer %p name %s\n",
00633                   retval, error, error->name ? error->name : "(none)");
00634       _dbus_assert_not_reached ("didn't handle errors properly");
00635     }
00636   
00637   if (keys != NULL)
00638     {
00639       i = 0;
00640       while (i < n_keys)
00641         {
00642           _dbus_string_zero (&keys[i].secret);
00643           _dbus_string_free (&keys[i].secret);
00644           ++i;
00645         }
00646 
00647       dbus_free (keys);
00648     }
00649   
00650   _dbus_string_free (&contents);
00651   _dbus_string_free (&line);
00652 
00653   return retval;
00654 }
00655  /* end of internals */
00657 
00670 DBusKeyring *
00671 _dbus_keyring_ref (DBusKeyring *keyring)
00672 {
00673   keyring->refcount += 1;
00674 
00675   return keyring;
00676 }
00677 
00684 void
00685 _dbus_keyring_unref (DBusKeyring *keyring)
00686 {
00687   keyring->refcount -= 1;
00688 
00689   if (keyring->refcount == 0)
00690     {
00691       _dbus_string_free (&keyring->username);
00692       _dbus_string_free (&keyring->filename);
00693       _dbus_string_free (&keyring->filename_lock);
00694       _dbus_string_free (&keyring->directory);
00695       free_keys (keyring->keys, keyring->n_keys);
00696       dbus_free (keyring);      
00697     }
00698 }
00699 
00710 DBusKeyring*
00711 _dbus_keyring_new_homedir (const DBusString *username,
00712                            const DBusString *context,
00713                            DBusError        *error)
00714 {
00715   DBusString homedir;
00716   DBusKeyring *keyring;
00717   dbus_bool_t error_set;
00718   DBusString dotdir;
00719   DBusError tmp_error;
00720 
00721   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00722   
00723   keyring = NULL;
00724   error_set = FALSE;
00725   
00726   if (!_dbus_string_init (&homedir))
00727     {
00728       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00729       return FALSE;
00730     }
00731 
00732   _dbus_string_init_const (&dotdir, ".dbus-keyrings");
00733   
00734   if (username == NULL)
00735     {
00736       const DBusString *const_homedir;
00737 
00738       if (!_dbus_username_from_current_process (&username) ||
00739           !_dbus_homedir_from_current_process (&const_homedir))
00740         goto failed;
00741 
00742       if (!_dbus_string_copy (const_homedir, 0,
00743                               &homedir, 0))
00744         goto failed;
00745     }
00746   else
00747     {
00748       if (!_dbus_homedir_from_username (username, &homedir))
00749         goto failed;
00750     }
00751 
00752 #ifdef DBUS_BUILD_TESTS
00753  {
00754    const char *override;
00755 
00756    override = _dbus_getenv ("DBUS_TEST_HOMEDIR");
00757    if (override != NULL && *override != '\0')
00758      {
00759        _dbus_string_set_length (&homedir, 0);
00760        if (!_dbus_string_append (&homedir, override))
00761          _dbus_assert_not_reached ("no memory");
00762 
00763        _dbus_verbose ("Using fake homedir for testing: %s\n",
00764                       _dbus_string_get_const_data (&homedir));
00765      }
00766    else
00767      {
00768        static dbus_bool_t already_warned = FALSE;
00769        if (!already_warned)
00770          {
00771            _dbus_warn ("Using your real home directory for testing, set DBUS_TEST_HOMEDIR to avoid\n");
00772            already_warned = TRUE;
00773          }
00774      }
00775  }
00776 #endif
00777   
00778   _dbus_assert (username != NULL);    
00779   
00780   keyring = _dbus_keyring_new ();
00781   if (keyring == NULL)
00782     goto failed;
00783 
00784   /* should have been validated already, but paranoia check here */
00785   if (!_dbus_keyring_validate_context (context))
00786     {
00787       error_set = TRUE;
00788       dbus_set_error_const (error,
00789                             DBUS_ERROR_FAILED,
00790                             "Invalid context in keyring creation");
00791       goto failed;
00792     }
00793 
00794   if (!_dbus_string_copy (username, 0,
00795                           &keyring->username, 0))
00796     goto failed;
00797   
00798   if (!_dbus_string_copy (&homedir, 0,
00799                           &keyring->directory, 0))
00800     goto failed;
00801   
00802   if (!_dbus_concat_dir_and_file (&keyring->directory,
00803                                   &dotdir))
00804     goto failed;
00805 
00806   if (!_dbus_string_copy (&keyring->directory, 0,
00807                           &keyring->filename, 0))
00808     goto failed;
00809 
00810   if (!_dbus_concat_dir_and_file (&keyring->filename,
00811                                   context))
00812     goto failed;
00813 
00814   if (!_dbus_string_copy (&keyring->filename, 0,
00815                           &keyring->filename_lock, 0))
00816     goto failed;
00817 
00818   if (!_dbus_string_append (&keyring->filename_lock, ".lock"))
00819     goto failed;
00820 
00821   dbus_error_init (&tmp_error);
00822   if (!_dbus_keyring_reload (keyring, FALSE, &tmp_error))
00823     {
00824       _dbus_verbose ("didn't load an existing keyring: %s\n",
00825                      tmp_error.message);
00826       dbus_error_free (&tmp_error);
00827     }
00828   
00829   /* We don't fail fatally if we can't create the directory,
00830    * but the keyring will probably always be empty
00831    * unless someone else manages to create it
00832    */
00833   dbus_error_init (&tmp_error);
00834   if (!_dbus_create_directory (&keyring->directory,
00835                                &tmp_error))
00836     {
00837       _dbus_verbose ("Creating keyring directory: %s\n",
00838                      tmp_error.message);
00839       dbus_error_free (&tmp_error);
00840     }
00841 
00842   _dbus_string_free (&homedir);
00843   
00844   return keyring;
00845   
00846  failed:
00847   if (!error_set)
00848     dbus_set_error_const (error,
00849                           DBUS_ERROR_NO_MEMORY,
00850                           NULL);
00851   if (keyring)
00852     _dbus_keyring_unref (keyring);
00853   _dbus_string_free (&homedir);
00854   return FALSE;
00855 
00856 }
00857 
00870 dbus_bool_t
00871 _dbus_keyring_validate_context (const DBusString *context)
00872 {
00873   if (_dbus_string_get_length (context) == 0)
00874     {
00875       _dbus_verbose ("context is zero-length\n");
00876       return FALSE;
00877     }
00878 
00879   if (!_dbus_string_validate_ascii (context, 0,
00880                                     _dbus_string_get_length (context)))
00881     {
00882       _dbus_verbose ("context not valid ascii\n");
00883       return FALSE;
00884     }
00885   
00886   /* no directory separators */  
00887   if (_dbus_string_find (context, 0, "/", NULL))
00888     {
00889       _dbus_verbose ("context contains a slash\n");
00890       return FALSE;
00891     }
00892 
00893   if (_dbus_string_find (context, 0, "\\", NULL))
00894     {
00895       _dbus_verbose ("context contains a backslash\n");
00896       return FALSE;
00897     }
00898 
00899   /* prevent attempts to use dotfiles or ".." or ".lock"
00900    * all of which might allow some kind of attack
00901    */
00902   if (_dbus_string_find (context, 0, ".", NULL))
00903     {
00904       _dbus_verbose ("context contains a dot\n");
00905       return FALSE;
00906     }
00907 
00908   /* no spaces/tabs, those are used for separators in the protocol */
00909   if (_dbus_string_find_blank (context, 0, NULL))
00910     {
00911       _dbus_verbose ("context contains a blank\n");
00912       return FALSE;
00913     }
00914 
00915   if (_dbus_string_find (context, 0, "\n", NULL))
00916     {
00917       _dbus_verbose ("context contains a newline\n");
00918       return FALSE;
00919     }
00920 
00921   if (_dbus_string_find (context, 0, "\r", NULL))
00922     {
00923       _dbus_verbose ("context contains a carriage return\n");
00924       return FALSE;
00925     }
00926   
00927   return TRUE;
00928 }
00929 
00930 static DBusKey*
00931 find_recent_key (DBusKeyring *keyring)
00932 {
00933   int i;
00934   long tv_sec, tv_usec;
00935 
00936   _dbus_get_current_time (&tv_sec, &tv_usec);
00937   
00938   i = 0;
00939   while (i < keyring->n_keys)
00940     {
00941       DBusKey *key = &keyring->keys[i];
00942 
00943       _dbus_verbose ("Key %d is %ld seconds old\n",
00944                      i, tv_sec - key->creation_time);
00945       
00946       if ((tv_sec - NEW_KEY_TIMEOUT_SECONDS) < key->creation_time)
00947         return key;
00948       
00949       ++i;
00950     }
00951 
00952   return NULL;
00953 }
00954 
00966 int
00967 _dbus_keyring_get_best_key (DBusKeyring  *keyring,
00968                             DBusError    *error)
00969 {
00970   DBusKey *key;
00971 
00972   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00973   
00974   key = find_recent_key (keyring);
00975   if (key)
00976     return key->id;
00977 
00978   /* All our keys are too old, or we've never loaded the
00979    * keyring. Create a new one.
00980    */
00981   if (!_dbus_keyring_reload (keyring, TRUE,
00982                              error))
00983     return -1;
00984 
00985   key = find_recent_key (keyring);
00986   if (key)
00987     return key->id;
00988   else
00989     {
00990       dbus_set_error_const (error,
00991                             DBUS_ERROR_FAILED,
00992                             "No recent-enough key found in keyring, and unable to create a new key");
00993       return -1;
00994     }
00995 }
00996 
01005 dbus_bool_t
01006 _dbus_keyring_is_for_user (DBusKeyring       *keyring,
01007                            const DBusString  *username)
01008 {
01009   return _dbus_string_equal (&keyring->username,
01010                              username);
01011 }
01012 
01024 dbus_bool_t
01025 _dbus_keyring_get_hex_key (DBusKeyring       *keyring,
01026                            int                key_id,
01027                            DBusString        *hex_key)
01028 {
01029   DBusKey *key;
01030 
01031   key = find_key_by_id (keyring->keys,
01032                         keyring->n_keys,
01033                         key_id);
01034   if (key == NULL)
01035     return TRUE; /* had enough memory, so TRUE */
01036 
01037   return _dbus_string_hex_encode (&key->secret, 0,
01038                                   hex_key,
01039                                   _dbus_string_get_length (hex_key));
01040 }
01041  /* end of exposed API */
01043 
01044 #ifdef DBUS_BUILD_TESTS
01045 #include "dbus-test.h"
01046 #include <stdio.h>
01047 
01048 dbus_bool_t
01049 _dbus_keyring_test (void)
01050 {
01051   DBusString context;
01052   DBusKeyring *ring1;
01053   DBusKeyring *ring2;
01054   int id;
01055   DBusError error;
01056   int i;
01057 
01058   ring1 = NULL;
01059   ring2 = NULL;
01060   
01061   /* Context validation */
01062   
01063   _dbus_string_init_const (&context, "foo");
01064   _dbus_assert (_dbus_keyring_validate_context (&context));
01065   _dbus_string_init_const (&context, "org_freedesktop_blah");
01066   _dbus_assert (_dbus_keyring_validate_context (&context));
01067   
01068   _dbus_string_init_const (&context, "");
01069   _dbus_assert (!_dbus_keyring_validate_context (&context));
01070   _dbus_string_init_const (&context, ".foo");
01071   _dbus_assert (!_dbus_keyring_validate_context (&context));
01072   _dbus_string_init_const (&context, "bar.foo");
01073   _dbus_assert (!_dbus_keyring_validate_context (&context));
01074   _dbus_string_init_const (&context, "bar/foo");
01075   _dbus_assert (!_dbus_keyring_validate_context (&context));
01076   _dbus_string_init_const (&context, "bar\\foo");
01077   _dbus_assert (!_dbus_keyring_validate_context (&context));
01078   _dbus_string_init_const (&context, "foo\xfa\xf0");
01079   _dbus_assert (!_dbus_keyring_validate_context (&context));
01080   _dbus_string_init_const (&context, "foo\x80");
01081   _dbus_assert (!_dbus_keyring_validate_context (&context));
01082   _dbus_string_init_const (&context, "foo\x7f");
01083   _dbus_assert (_dbus_keyring_validate_context (&context));
01084   _dbus_string_init_const (&context, "foo bar");
01085   _dbus_assert (!_dbus_keyring_validate_context (&context));
01086   
01087   if (!_dbus_string_init (&context))
01088     _dbus_assert_not_reached ("no memory");
01089   if (!_dbus_string_append_byte (&context, '\0'))
01090     _dbus_assert_not_reached ("no memory");
01091   _dbus_assert (!_dbus_keyring_validate_context (&context));
01092   _dbus_string_free (&context);
01093 
01094   /* Now verify that if we create a key in keyring 1,
01095    * it is properly loaded in keyring 2
01096    */
01097 
01098   _dbus_string_init_const (&context, "org_freedesktop_dbus_testsuite");
01099   dbus_error_init (&error);
01100   ring1 = _dbus_keyring_new_homedir (NULL, &context,
01101                                      &error);
01102   _dbus_assert (ring1);
01103   _dbus_assert (error.name == NULL);
01104 
01105   id = _dbus_keyring_get_best_key (ring1, &error);
01106   if (id < 0)
01107     {
01108       fprintf (stderr, "Could not load keyring: %s\n", error.message);
01109       dbus_error_free (&error);
01110       goto failure;
01111     }
01112 
01113   ring2 = _dbus_keyring_new_homedir (NULL, &context, &error);
01114   _dbus_assert (ring2);
01115   _dbus_assert (error.name == NULL);
01116   
01117   if (ring1->n_keys != ring2->n_keys)
01118     {
01119       fprintf (stderr, "Different number of keys in keyrings\n");
01120       goto failure;
01121     }
01122 
01123   /* We guarantee we load and save keeping keys in a fixed
01124    * order
01125    */
01126   i = 0;
01127   while (i < ring1->n_keys)
01128     {
01129       if (ring1->keys[i].id != ring2->keys[i].id)
01130         {
01131           fprintf (stderr, "Keyring 1 has first key ID %d and keyring 2 has %d\n",
01132                    ring1->keys[i].id, ring2->keys[i].id);
01133           goto failure;
01134         }      
01135 
01136       if (ring1->keys[i].creation_time != ring2->keys[i].creation_time)
01137         {
01138           fprintf (stderr, "Keyring 1 has first key time %ld and keyring 2 has %ld\n",
01139                    ring1->keys[i].creation_time, ring2->keys[i].creation_time);
01140           goto failure;
01141         }
01142 
01143       if (!_dbus_string_equal (&ring1->keys[i].secret,
01144                                &ring2->keys[i].secret))
01145         {
01146           fprintf (stderr, "Keyrings 1 and 2 have different secrets for same ID/timestamp\n");
01147           goto failure;
01148         }
01149       
01150       ++i;
01151     }
01152 
01153   printf (" %d keys in test\n", ring1->n_keys);
01154 
01155   /* Test ref/unref */
01156   _dbus_keyring_ref (ring1);
01157   _dbus_keyring_ref (ring2);
01158   _dbus_keyring_unref (ring1);
01159   _dbus_keyring_unref (ring2);
01160 
01161 
01162   /* really unref */
01163   _dbus_keyring_unref (ring1);
01164   _dbus_keyring_unref (ring2);
01165   
01166   return TRUE;
01167 
01168  failure:
01169   if (ring1)
01170     _dbus_keyring_unref (ring1);
01171   if (ring2)
01172     _dbus_keyring_unref (ring2);
01173 
01174   return FALSE;
01175 }
01176 
01177 #endif /* DBUS_BUILD_TESTS */
01178      

Generated on Wed Jun 9 05:01:25 2004 for D-BUS by doxygen1.2.15