dbus-keyring.c

00001 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
00002 /* dbus-keyring.c Store secret cookies in your homedir
00003  *
00004  * Copyright (C) 2003, 2004  Red Hat Inc.
00005  *
00006  * Licensed under the Academic Free License version 2.1
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-protocol.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 directory;     
00114   DBusString filename;      
00115   DBusString filename_lock; 
00116   DBusKey *keys; 
00117   int n_keys;    
00118   DBusCredentials *credentials; 
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   keyring->refcount = 1;
00140   keyring->keys = NULL;
00141   keyring->n_keys = 0;
00142 
00143   return keyring;
00144 
00145   /*  out_4: */
00146   _dbus_string_free (&keyring->filename_lock);
00147  out_3:
00148   _dbus_string_free (&keyring->filename);
00149  out_2:
00150   _dbus_string_free (&keyring->directory);
00151  out_1:
00152   dbus_free (keyring);
00153  out_0:
00154   return NULL;
00155 }
00156 
00157 static void
00158 free_keys (DBusKey *keys,
00159            int      n_keys)
00160 {
00161   int i;
00162 
00163   /* should be safe for args NULL, 0 */
00164   
00165   i = 0;
00166   while (i < n_keys)
00167     {
00168       _dbus_string_free (&keys[i].secret);
00169       ++i;
00170     }
00171 
00172   dbus_free (keys);
00173 }
00174 
00175 /* Our locking scheme is highly unreliable.  However, there is
00176  * unfortunately no reliable locking scheme in user home directories;
00177  * between bugs in Linux NFS, people using Tru64 or other total crap
00178  * NFS, AFS, random-file-system-of-the-week, and so forth, fcntl() in
00179  * homedirs simply generates tons of bug reports. This has been
00180  * learned through hard experience with GConf, unfortunately.
00181  *
00182  * This bad hack might work better for the kind of lock we have here,
00183  * which we don't expect to hold for any length of time.  Crashing
00184  * while we hold it should be unlikely, and timing out such that we
00185  * delete a stale lock should also be unlikely except when the
00186  * filesystem is running really slowly.  Stuff might break in corner
00187  * cases but as long as it's not a security-level breakage it should
00188  * be OK.
00189  */
00190 
00192 #define MAX_LOCK_TIMEOUTS 32
00193 
00194 #define LOCK_TIMEOUT_MILLISECONDS 250
00195 
00196 static dbus_bool_t
00197 _dbus_keyring_lock (DBusKeyring *keyring)
00198 {
00199   int n_timeouts;
00200   
00201   n_timeouts = 0;
00202   while (n_timeouts < MAX_LOCK_TIMEOUTS)
00203     {
00204       DBusError error = DBUS_ERROR_INIT;
00205 
00206       if (_dbus_create_file_exclusively (&keyring->filename_lock,
00207                                          &error))
00208         break;
00209 
00210       _dbus_verbose ("Did not get lock file, sleeping %d milliseconds (%s)\n",
00211                      LOCK_TIMEOUT_MILLISECONDS, error.message);
00212       dbus_error_free (&error);
00213 
00214       _dbus_sleep_milliseconds (LOCK_TIMEOUT_MILLISECONDS);
00215       
00216       ++n_timeouts;
00217     }
00218 
00219   if (n_timeouts == MAX_LOCK_TIMEOUTS)
00220     {
00221       DBusError error = DBUS_ERROR_INIT;
00222 
00223       _dbus_verbose ("Lock file timed out %d times, assuming stale\n",
00224                      n_timeouts);
00225 
00226       if (!_dbus_delete_file (&keyring->filename_lock, &error))
00227         {
00228           _dbus_verbose ("Couldn't delete old lock file: %s\n",
00229                          error.message);
00230           dbus_error_free (&error);
00231           return FALSE;
00232         }
00233 
00234       if (!_dbus_create_file_exclusively (&keyring->filename_lock,
00235                                           &error))
00236         {
00237           _dbus_verbose ("Couldn't create lock file after deleting stale one: %s\n",
00238                          error.message);
00239           dbus_error_free (&error);
00240           return FALSE;
00241         }
00242     }
00243   
00244   return TRUE;
00245 }
00246 
00247 static void
00248 _dbus_keyring_unlock (DBusKeyring *keyring)
00249 {
00250   DBusError error = DBUS_ERROR_INIT;
00251 
00252   if (!_dbus_delete_file (&keyring->filename_lock, &error))
00253     {
00254       _dbus_warn ("Failed to delete lock file: %s\n",
00255                   error.message);
00256       dbus_error_free (&error);
00257     }
00258 }
00259 
00260 static DBusKey*
00261 find_key_by_id (DBusKey *keys,
00262                 int      n_keys,
00263                 int      id)
00264 {
00265   int i;
00266 
00267   i = 0;
00268   while (i < n_keys)
00269     {
00270       if (keys[i].id == id)
00271         return &keys[i];
00272       
00273       ++i;
00274     }
00275 
00276   return NULL;
00277 }
00278 
00279 static dbus_bool_t
00280 add_new_key (DBusKey  **keys_p,
00281              int       *n_keys_p,
00282              DBusError *error)
00283 {
00284   DBusKey *new;
00285   DBusString bytes;
00286   int id;
00287   long timestamp;
00288   const unsigned char *s;
00289   dbus_bool_t retval;
00290   DBusKey *keys;
00291   int n_keys;
00292 
00293   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00294   
00295   if (!_dbus_string_init (&bytes))
00296     {
00297       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00298       return FALSE;
00299     }
00300 
00301   keys = *keys_p;
00302   n_keys = *n_keys_p;
00303   retval = FALSE;
00304       
00305   /* Generate an integer ID and then the actual key. */
00306  retry:
00307       
00308   if (!_dbus_generate_random_bytes (&bytes, 4))
00309     {
00310       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00311       goto out;
00312     }
00313 
00314   s = (const unsigned char*) _dbus_string_get_const_data (&bytes);
00315       
00316   id = s[0] | (s[1] << 8) | (s[2] << 16) | (s[3] << 24);
00317   if (id < 0)
00318     id = - id;
00319   _dbus_assert (id >= 0);
00320 
00321   if (find_key_by_id (keys, n_keys, id) != NULL)
00322     {
00323       _dbus_string_set_length (&bytes, 0);
00324       _dbus_verbose ("Key ID %d already existed, trying another one\n",
00325                      id);
00326       goto retry;
00327     }
00328 
00329   _dbus_verbose ("Creating key with ID %d\n", id);
00330       
00331 #define KEY_LENGTH_BYTES 24
00332   _dbus_string_set_length (&bytes, 0);
00333   if (!_dbus_generate_random_bytes (&bytes, KEY_LENGTH_BYTES))
00334     {
00335       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00336       goto out;
00337     }
00338 
00339   new = dbus_realloc (keys, sizeof (DBusKey) * (n_keys + 1));
00340   if (new == NULL)
00341     {
00342       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00343       goto out;
00344     }
00345 
00346   keys = new;
00347   *keys_p = keys; /* otherwise *keys_p ends up invalid */
00348   n_keys += 1;
00349 
00350   if (!_dbus_string_init (&keys[n_keys-1].secret))
00351     {
00352       n_keys -= 1; /* we don't want to free the one we didn't init */
00353       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00354       goto out;
00355     }
00356 
00357   _dbus_get_current_time (&timestamp, NULL);
00358       
00359   keys[n_keys-1].id = id;
00360   keys[n_keys-1].creation_time = timestamp;
00361   if (!_dbus_string_move (&bytes, 0,
00362                           &keys[n_keys-1].secret,
00363                           0))
00364     {
00365       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00366       _dbus_string_free (&keys[n_keys-1].secret);
00367       n_keys -= 1;
00368       goto out;
00369     }
00370   
00371   retval = TRUE;
00372   
00373  out:
00374   *n_keys_p = n_keys;
00375   
00376   _dbus_string_free (&bytes);
00377   return retval;
00378 }
00379 
00394 static dbus_bool_t
00395 _dbus_keyring_reload (DBusKeyring *keyring,
00396                       dbus_bool_t  add_new,
00397                       DBusError   *error)
00398 {
00399   DBusString contents;
00400   DBusString line;
00401   dbus_bool_t retval;
00402   dbus_bool_t have_lock;
00403   DBusKey *keys;
00404   int n_keys;
00405   int i;
00406   long now;
00407   DBusError tmp_error;
00408 
00409   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00410   
00411   if (!_dbus_check_dir_is_private_to_user (&keyring->directory, error))
00412     return FALSE;
00413     
00414   if (!_dbus_string_init (&contents))
00415     {
00416       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00417       return FALSE;
00418     }
00419 
00420   if (!_dbus_string_init (&line))
00421     {
00422       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00423       _dbus_string_free (&contents);
00424       return FALSE;
00425     }
00426    
00427   keys = NULL;
00428   n_keys = 0;
00429   retval = FALSE;
00430   have_lock = FALSE;
00431 
00432   _dbus_get_current_time (&now, NULL);
00433   
00434   if (add_new)
00435     {
00436       if (!_dbus_keyring_lock (keyring))
00437         {
00438           dbus_set_error (error, DBUS_ERROR_FAILED,
00439                           "Could not lock keyring file to add to it");
00440           goto out;
00441         }
00442 
00443       have_lock = TRUE;
00444     }
00445 
00446   dbus_error_init (&tmp_error);
00447   if (!_dbus_file_get_contents (&contents, 
00448                                 &keyring->filename,
00449                                 &tmp_error))
00450     {
00451       _dbus_verbose ("Failed to load keyring file: %s\n",
00452                      tmp_error.message);
00453       /* continue with empty keyring file, so we recreate it */
00454       dbus_error_free (&tmp_error);
00455     }
00456 
00457   if (!_dbus_string_validate_ascii (&contents, 0,
00458                                     _dbus_string_get_length (&contents)))
00459     {
00460       _dbus_warn ("Secret keyring file contains non-ASCII! Ignoring existing contents\n");
00461       _dbus_string_set_length (&contents, 0);
00462     }
00463 
00464   /* FIXME this is badly inefficient for large keyring files
00465    * (not that large keyring files exist outside of test suites)
00466    */
00467   while (_dbus_string_pop_line (&contents, &line))
00468     {
00469       int next;
00470       long val;
00471       int id;
00472       long timestamp;
00473       int len;
00474       int end;
00475       DBusKey *new;
00476 
00477       /* Don't load more than the max. */
00478       if (n_keys >= (add_new ? MAX_KEYS_IN_FILE - 1 : MAX_KEYS_IN_FILE))
00479         break;
00480       
00481       next = 0;
00482       if (!_dbus_string_parse_int (&line, 0, &val, &next))
00483         {
00484           _dbus_verbose ("could not parse secret key ID at start of line\n");
00485           continue;
00486         }
00487 
00488       if (val > _DBUS_INT32_MAX || val < 0)
00489         {
00490           _dbus_verbose ("invalid secret key ID at start of line\n");
00491           continue;
00492         }
00493       
00494       id = val;
00495 
00496       _dbus_string_skip_blank (&line, next, &next);
00497       
00498       if (!_dbus_string_parse_int (&line, next, &timestamp, &next))
00499         {
00500           _dbus_verbose ("could not parse secret key timestamp\n");
00501           continue;
00502         }
00503 
00504       if (timestamp < 0 ||
00505           (now + MAX_TIME_TRAVEL_SECONDS) < timestamp ||
00506           (now - EXPIRE_KEYS_TIMEOUT_SECONDS) > timestamp)
00507         {
00508           _dbus_verbose ("dropping/ignoring %ld-seconds old key with timestamp %ld as current time is %ld\n",
00509                          now - timestamp, timestamp, now);
00510           continue;
00511         }
00512       
00513       _dbus_string_skip_blank (&line, next, &next);
00514 
00515       len = _dbus_string_get_length (&line);
00516 
00517       if ((len - next) == 0)
00518         {
00519           _dbus_verbose ("no secret key after ID and timestamp\n");
00520           continue;
00521         }
00522       
00523       /* We have all three parts */
00524       new = dbus_realloc (keys, sizeof (DBusKey) * (n_keys + 1));
00525       if (new == NULL)
00526         {
00527           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00528           goto out;
00529         }
00530 
00531       keys = new;
00532       n_keys += 1;
00533 
00534       if (!_dbus_string_init (&keys[n_keys-1].secret))
00535         {
00536           n_keys -= 1; /* we don't want to free the one we didn't init */
00537           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00538           goto out;
00539         }
00540       
00541       keys[n_keys-1].id = id;
00542       keys[n_keys-1].creation_time = timestamp;
00543       if (!_dbus_string_hex_decode (&line, next, &end,
00544                                     &keys[n_keys-1].secret, 0))
00545         {
00546           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00547           goto out;
00548         }
00549 
00550       if (_dbus_string_get_length (&line) != end)
00551         {
00552           _dbus_verbose ("invalid hex encoding in keyring file\n");
00553           _dbus_string_free (&keys[n_keys - 1].secret);
00554           n_keys -= 1;
00555           continue;
00556         }
00557     }
00558 
00559   _dbus_verbose ("Successfully loaded %d existing keys\n",
00560                  n_keys);
00561 
00562   if (add_new)
00563     {
00564       if (!add_new_key (&keys, &n_keys, error))
00565         {
00566           _dbus_verbose ("Failed to generate new key: %s\n",
00567                          error ? error->message : "(unknown)");
00568           goto out;
00569         }
00570 
00571       _dbus_string_set_length (&contents, 0);
00572 
00573       i = 0;
00574       while (i < n_keys)
00575         {
00576           if (!_dbus_string_append_int (&contents,
00577                                         keys[i].id))
00578             goto nomem;
00579 
00580           if (!_dbus_string_append_byte (&contents, ' '))
00581             goto nomem;
00582 
00583           if (!_dbus_string_append_int (&contents,
00584                                         keys[i].creation_time))
00585             goto nomem;
00586 
00587           if (!_dbus_string_append_byte (&contents, ' '))
00588             goto nomem;
00589 
00590           if (!_dbus_string_hex_encode (&keys[i].secret, 0,
00591                                         &contents,
00592                                         _dbus_string_get_length (&contents)))
00593             goto nomem;
00594 
00595           if (!_dbus_string_append_byte (&contents, '\n'))
00596             goto nomem;          
00597           
00598           ++i;
00599           continue;
00600 
00601         nomem:
00602           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00603           goto out;
00604         }
00605       
00606       if (!_dbus_string_save_to_file (&contents, &keyring->filename,
00607                                       error))
00608         goto out;
00609     }
00610 
00611   if (keyring->keys)
00612     free_keys (keyring->keys, keyring->n_keys);
00613   keyring->keys = keys;
00614   keyring->n_keys = n_keys;
00615   keys = NULL;
00616   n_keys = 0;
00617   
00618   retval = TRUE;  
00619   
00620  out:
00621   if (have_lock)
00622     _dbus_keyring_unlock (keyring);
00623   
00624   if (! ((retval == TRUE && (error == NULL || error->name == NULL)) ||
00625          (retval == FALSE && (error == NULL || error->name != NULL))))
00626     {
00627       if (error && error->name)
00628         _dbus_verbose ("error is %s: %s\n", error->name, error->message);
00629       _dbus_warn ("returning %d but error pointer %p name %s\n",
00630                   retval, error, error->name ? error->name : "(none)");
00631       _dbus_assert_not_reached ("didn't handle errors properly");
00632     }
00633   
00634   if (keys != NULL)
00635     {
00636       i = 0;
00637       while (i < n_keys)
00638         {
00639           _dbus_string_zero (&keys[i].secret);
00640           _dbus_string_free (&keys[i].secret);
00641           ++i;
00642         }
00643 
00644       dbus_free (keys);
00645     }
00646   
00647   _dbus_string_free (&contents);
00648   _dbus_string_free (&line);
00649 
00650   return retval;
00651 }
00652  /* end of internals */
00654 
00667 DBusKeyring *
00668 _dbus_keyring_ref (DBusKeyring *keyring)
00669 {
00670   keyring->refcount += 1;
00671 
00672   return keyring;
00673 }
00674 
00681 void
00682 _dbus_keyring_unref (DBusKeyring *keyring)
00683 {
00684   keyring->refcount -= 1;
00685 
00686   if (keyring->refcount == 0)
00687     {
00688       if (keyring->credentials)
00689         _dbus_credentials_unref (keyring->credentials);
00690 
00691       _dbus_string_free (&keyring->filename);
00692       _dbus_string_free (&keyring->filename_lock);
00693       _dbus_string_free (&keyring->directory);
00694       free_keys (keyring->keys, keyring->n_keys);
00695       dbus_free (keyring);      
00696     }
00697 }
00698 
00709 DBusKeyring*
00710 _dbus_keyring_new_for_credentials (DBusCredentials  *credentials,
00711                                    const DBusString *context,
00712                                    DBusError        *error)
00713 {
00714   DBusString ringdir;
00715   DBusKeyring *keyring;
00716   dbus_bool_t error_set;
00717   DBusError tmp_error;
00718   DBusCredentials *our_credentials;
00719   
00720   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00721   
00722   keyring = NULL;
00723   error_set = FALSE;
00724   our_credentials = NULL;
00725   
00726   if (!_dbus_string_init (&ringdir))
00727     {
00728       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00729       return NULL;
00730     }
00731 
00732   if (credentials != NULL)
00733     {
00734       our_credentials = _dbus_credentials_copy (credentials);
00735     }
00736   else
00737     {
00738       our_credentials = _dbus_credentials_new_from_current_process ();
00739     }
00740   
00741   if (our_credentials == NULL)
00742     goto failed;
00743 
00744   if (_dbus_credentials_are_anonymous (our_credentials))
00745     {
00746       if (!_dbus_credentials_add_from_current_process (our_credentials))
00747         goto failed;
00748     }
00749   
00750   if (!_dbus_append_keyring_directory_for_credentials (&ringdir,
00751                                                        our_credentials))
00752     goto failed;
00753   
00754   keyring = _dbus_keyring_new ();
00755   if (keyring == NULL)
00756     goto failed;
00757 
00758   _dbus_assert (keyring->credentials == NULL);
00759   keyring->credentials = our_credentials;
00760   our_credentials = NULL; /* so we don't unref it again later */
00761   
00762   /* should have been validated already, but paranoia check here */
00763   if (!_dbus_keyring_validate_context (context))
00764     {
00765       error_set = TRUE;
00766       dbus_set_error_const (error,
00767                             DBUS_ERROR_FAILED,
00768                             "Invalid context in keyring creation");
00769       goto failed;
00770     }
00771 
00772   /* Save keyring dir in the keyring object */
00773   if (!_dbus_string_copy (&ringdir, 0,
00774                           &keyring->directory, 0))
00775     goto failed;  
00776 
00777   /* Create keyring->filename based on keyring dir and context */
00778   if (!_dbus_string_copy (&keyring->directory, 0,
00779                           &keyring->filename, 0))
00780     goto failed;
00781 
00782   if (!_dbus_concat_dir_and_file (&keyring->filename,
00783                                   context))
00784     goto failed;
00785 
00786   /* Create lockfile name */
00787   if (!_dbus_string_copy (&keyring->filename, 0,
00788                           &keyring->filename_lock, 0))
00789     goto failed;
00790 
00791   if (!_dbus_string_append (&keyring->filename_lock, ".lock"))
00792     goto failed;
00793 
00794   /* Reload keyring */
00795   dbus_error_init (&tmp_error);
00796   if (!_dbus_keyring_reload (keyring, FALSE, &tmp_error))
00797     {
00798       _dbus_verbose ("didn't load an existing keyring: %s\n",
00799                      tmp_error.message);
00800       dbus_error_free (&tmp_error);
00801     }
00802   
00803   /* We don't fail fatally if we can't create the directory,
00804    * but the keyring will probably always be empty
00805    * unless someone else manages to create it
00806    */
00807   dbus_error_init (&tmp_error);
00808   if (!_dbus_create_directory (&keyring->directory,
00809                                &tmp_error))
00810     {
00811       _dbus_verbose ("Creating keyring directory: %s\n",
00812                      tmp_error.message);
00813       dbus_error_free (&tmp_error);
00814     }
00815 
00816   _dbus_string_free (&ringdir);
00817   
00818   return keyring;
00819   
00820  failed:
00821   if (!error_set)
00822     dbus_set_error_const (error,
00823                           DBUS_ERROR_NO_MEMORY,
00824                           NULL);
00825   if (our_credentials)
00826     _dbus_credentials_unref (our_credentials);
00827   if (keyring)
00828     _dbus_keyring_unref (keyring);
00829   _dbus_string_free (&ringdir);
00830   return NULL;
00831 
00832 }
00833 
00846 dbus_bool_t
00847 _dbus_keyring_validate_context (const DBusString *context)
00848 {
00849   if (_dbus_string_get_length (context) == 0)
00850     {
00851       _dbus_verbose ("context is zero-length\n");
00852       return FALSE;
00853     }
00854 
00855   if (!_dbus_string_validate_ascii (context, 0,
00856                                     _dbus_string_get_length (context)))
00857     {
00858       _dbus_verbose ("context not valid ascii\n");
00859       return FALSE;
00860     }
00861   
00862   /* no directory separators */  
00863   if (_dbus_string_find (context, 0, "/", NULL))
00864     {
00865       _dbus_verbose ("context contains a slash\n");
00866       return FALSE;
00867     }
00868 
00869   if (_dbus_string_find (context, 0, "\\", NULL))
00870     {
00871       _dbus_verbose ("context contains a backslash\n");
00872       return FALSE;
00873     }
00874 
00875   /* prevent attempts to use dotfiles or ".." or ".lock"
00876    * all of which might allow some kind of attack
00877    */
00878   if (_dbus_string_find (context, 0, ".", NULL))
00879     {
00880       _dbus_verbose ("context contains a dot\n");
00881       return FALSE;
00882     }
00883 
00884   /* no spaces/tabs, those are used for separators in the protocol */
00885   if (_dbus_string_find_blank (context, 0, NULL))
00886     {
00887       _dbus_verbose ("context contains a blank\n");
00888       return FALSE;
00889     }
00890 
00891   if (_dbus_string_find (context, 0, "\n", NULL))
00892     {
00893       _dbus_verbose ("context contains a newline\n");
00894       return FALSE;
00895     }
00896 
00897   if (_dbus_string_find (context, 0, "\r", NULL))
00898     {
00899       _dbus_verbose ("context contains a carriage return\n");
00900       return FALSE;
00901     }
00902   
00903   return TRUE;
00904 }
00905 
00906 static DBusKey*
00907 find_recent_key (DBusKeyring *keyring)
00908 {
00909   int i;
00910   long tv_sec, tv_usec;
00911 
00912   _dbus_get_current_time (&tv_sec, &tv_usec);
00913   
00914   i = 0;
00915   while (i < keyring->n_keys)
00916     {
00917       DBusKey *key = &keyring->keys[i];
00918 
00919       _dbus_verbose ("Key %d is %ld seconds old\n",
00920                      i, tv_sec - key->creation_time);
00921       
00922       if ((tv_sec - NEW_KEY_TIMEOUT_SECONDS) < key->creation_time)
00923         return key;
00924       
00925       ++i;
00926     }
00927 
00928   return NULL;
00929 }
00930 
00942 int
00943 _dbus_keyring_get_best_key (DBusKeyring  *keyring,
00944                             DBusError    *error)
00945 {
00946   DBusKey *key;
00947 
00948   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00949   
00950   key = find_recent_key (keyring);
00951   if (key)
00952     return key->id;
00953 
00954   /* All our keys are too old, or we've never loaded the
00955    * keyring. Create a new one.
00956    */
00957   if (!_dbus_keyring_reload (keyring, TRUE,
00958                              error))
00959     return -1;
00960 
00961   key = find_recent_key (keyring);
00962   if (key)
00963     return key->id;
00964   else
00965     {
00966       dbus_set_error_const (error,
00967                             DBUS_ERROR_FAILED,
00968                             "No recent-enough key found in keyring, and unable to create a new key");
00969       return -1;
00970     }
00971 }
00972 
00981 dbus_bool_t
00982 _dbus_keyring_is_for_credentials (DBusKeyring           *keyring,
00983                                   DBusCredentials       *credentials)
00984 {
00985   return _dbus_credentials_same_user (keyring->credentials,
00986                                       credentials);
00987 }
00988 
01000 dbus_bool_t
01001 _dbus_keyring_get_hex_key (DBusKeyring       *keyring,
01002                            int                key_id,
01003                            DBusString        *hex_key)
01004 {
01005   DBusKey *key;
01006 
01007   key = find_key_by_id (keyring->keys,
01008                         keyring->n_keys,
01009                         key_id);
01010   if (key == NULL)
01011     return TRUE; /* had enough memory, so TRUE */
01012 
01013   return _dbus_string_hex_encode (&key->secret, 0,
01014                                   hex_key,
01015                                   _dbus_string_get_length (hex_key));
01016 }
01017  /* end of exposed API */
01019 
01020 #ifdef DBUS_BUILD_TESTS
01021 #include "dbus-test.h"
01022 #include <stdio.h>
01023 
01024 dbus_bool_t
01025 _dbus_keyring_test (void)
01026 {
01027   DBusString context;
01028   DBusKeyring *ring1;
01029   DBusKeyring *ring2;
01030   int id;
01031   DBusError error;
01032   int i;
01033 
01034   ring1 = NULL;
01035   ring2 = NULL;
01036   
01037   /* Context validation */
01038   
01039   _dbus_string_init_const (&context, "foo");
01040   _dbus_assert (_dbus_keyring_validate_context (&context));
01041   _dbus_string_init_const (&context, "org_freedesktop_blah");
01042   _dbus_assert (_dbus_keyring_validate_context (&context));
01043   
01044   _dbus_string_init_const (&context, "");
01045   _dbus_assert (!_dbus_keyring_validate_context (&context));
01046   _dbus_string_init_const (&context, ".foo");
01047   _dbus_assert (!_dbus_keyring_validate_context (&context));
01048   _dbus_string_init_const (&context, "bar.foo");
01049   _dbus_assert (!_dbus_keyring_validate_context (&context));
01050   _dbus_string_init_const (&context, "bar/foo");
01051   _dbus_assert (!_dbus_keyring_validate_context (&context));
01052   _dbus_string_init_const (&context, "bar\\foo");
01053   _dbus_assert (!_dbus_keyring_validate_context (&context));
01054   _dbus_string_init_const (&context, "foo\xfa\xf0");
01055   _dbus_assert (!_dbus_keyring_validate_context (&context));
01056   _dbus_string_init_const (&context, "foo\x80");
01057   _dbus_assert (!_dbus_keyring_validate_context (&context));
01058   _dbus_string_init_const (&context, "foo\x7f");
01059   _dbus_assert (_dbus_keyring_validate_context (&context));
01060   _dbus_string_init_const (&context, "foo bar");
01061   _dbus_assert (!_dbus_keyring_validate_context (&context));
01062   
01063   if (!_dbus_string_init (&context))
01064     _dbus_assert_not_reached ("no memory");
01065   if (!_dbus_string_append_byte (&context, '\0'))
01066     _dbus_assert_not_reached ("no memory");
01067   _dbus_assert (!_dbus_keyring_validate_context (&context));
01068   _dbus_string_free (&context);
01069 
01070   /* Now verify that if we create a key in keyring 1,
01071    * it is properly loaded in keyring 2
01072    */
01073 
01074   _dbus_string_init_const (&context, "org_freedesktop_dbus_testsuite");
01075   dbus_error_init (&error);
01076   ring1 = _dbus_keyring_new_for_credentials (NULL, &context,
01077                                              &error);
01078   _dbus_assert (ring1);
01079   _dbus_assert (error.name == NULL);
01080 
01081   id = _dbus_keyring_get_best_key (ring1, &error);
01082   if (id < 0)
01083     {
01084       fprintf (stderr, "Could not load keyring: %s\n", error.message);
01085       dbus_error_free (&error);
01086       goto failure;
01087     }
01088 
01089   ring2 = _dbus_keyring_new_for_credentials (NULL, &context, &error);
01090   _dbus_assert (ring2);
01091   _dbus_assert (error.name == NULL);
01092   
01093   if (ring1->n_keys != ring2->n_keys)
01094     {
01095       fprintf (stderr, "Different number of keys in keyrings\n");
01096       goto failure;
01097     }
01098 
01099   /* We guarantee we load and save keeping keys in a fixed
01100    * order
01101    */
01102   i = 0;
01103   while (i < ring1->n_keys)
01104     {
01105       if (ring1->keys[i].id != ring2->keys[i].id)
01106         {
01107           fprintf (stderr, "Keyring 1 has first key ID %d and keyring 2 has %d\n",
01108                    ring1->keys[i].id, ring2->keys[i].id);
01109           goto failure;
01110         }      
01111 
01112       if (ring1->keys[i].creation_time != ring2->keys[i].creation_time)
01113         {
01114           fprintf (stderr, "Keyring 1 has first key time %ld and keyring 2 has %ld\n",
01115                    ring1->keys[i].creation_time, ring2->keys[i].creation_time);
01116           goto failure;
01117         }
01118 
01119       if (!_dbus_string_equal (&ring1->keys[i].secret,
01120                                &ring2->keys[i].secret))
01121         {
01122           fprintf (stderr, "Keyrings 1 and 2 have different secrets for same ID/timestamp\n");
01123           goto failure;
01124         }
01125       
01126       ++i;
01127     }
01128 
01129   printf (" %d keys in test\n", ring1->n_keys);
01130 
01131   /* Test ref/unref */
01132   _dbus_keyring_ref (ring1);
01133   _dbus_keyring_ref (ring2);
01134   _dbus_keyring_unref (ring1);
01135   _dbus_keyring_unref (ring2);
01136 
01137 
01138   /* really unref */
01139   _dbus_keyring_unref (ring1);
01140   _dbus_keyring_unref (ring2);
01141   
01142   return TRUE;
01143 
01144  failure:
01145   if (ring1)
01146     _dbus_keyring_unref (ring1);
01147   if (ring2)
01148     _dbus_keyring_unref (ring2);
01149 
01150   return FALSE;
01151 }
01152 
01153 #endif /* DBUS_BUILD_TESTS */
01154      

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