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;
00205 
00206       dbus_error_init (&error);
00207       if (_dbus_create_file_exclusively (&keyring->filename_lock,
00208                                          &error))
00209         break;
00210 
00211       _dbus_verbose ("Did not get lock file, sleeping %d milliseconds (%s)\n",
00212                      LOCK_TIMEOUT_MILLISECONDS, error.message);
00213       dbus_error_free (&error);
00214 
00215       _dbus_sleep_milliseconds (LOCK_TIMEOUT_MILLISECONDS);
00216       
00217       ++n_timeouts;
00218     }
00219 
00220   if (n_timeouts == MAX_LOCK_TIMEOUTS)
00221     {
00222       DBusError error;
00223       
00224       _dbus_verbose ("Lock file timed out %d times, assuming stale\n",
00225                      n_timeouts);
00226 
00227       dbus_error_init (&error);
00228 
00229       if (!_dbus_delete_file (&keyring->filename_lock, &error))
00230         {
00231           _dbus_verbose ("Couldn't delete old lock file: %s\n",
00232                          error.message);
00233           dbus_error_free (&error);
00234           return FALSE;
00235         }
00236 
00237       if (!_dbus_create_file_exclusively (&keyring->filename_lock,
00238                                           &error))
00239         {
00240           _dbus_verbose ("Couldn't create lock file after deleting stale one: %s\n",
00241                          error.message);
00242           dbus_error_free (&error);
00243           return FALSE;
00244         }
00245     }
00246   
00247   return TRUE;
00248 }
00249 
00250 static void
00251 _dbus_keyring_unlock (DBusKeyring *keyring)
00252 {
00253   DBusError error;
00254   dbus_error_init (&error);
00255   if (!_dbus_delete_file (&keyring->filename_lock, &error))
00256     {
00257       _dbus_warn ("Failed to delete lock file: %s\n",
00258                   error.message);
00259       dbus_error_free (&error);
00260     }
00261 }
00262 
00263 static DBusKey*
00264 find_key_by_id (DBusKey *keys,
00265                 int      n_keys,
00266                 int      id)
00267 {
00268   int i;
00269 
00270   i = 0;
00271   while (i < n_keys)
00272     {
00273       if (keys[i].id == id)
00274         return &keys[i];
00275       
00276       ++i;
00277     }
00278 
00279   return NULL;
00280 }
00281 
00282 static dbus_bool_t
00283 add_new_key (DBusKey  **keys_p,
00284              int       *n_keys_p,
00285              DBusError *error)
00286 {
00287   DBusKey *new;
00288   DBusString bytes;
00289   int id;
00290   long timestamp;
00291   const unsigned char *s;
00292   dbus_bool_t retval;
00293   DBusKey *keys;
00294   int n_keys;
00295 
00296   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00297   
00298   if (!_dbus_string_init (&bytes))
00299     {
00300       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00301       return FALSE;
00302     }
00303 
00304   keys = *keys_p;
00305   n_keys = *n_keys_p;
00306   retval = FALSE;
00307       
00308   /* Generate an integer ID and then the actual key. */
00309  retry:
00310       
00311   if (!_dbus_generate_random_bytes (&bytes, 4))
00312     {
00313       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00314       goto out;
00315     }
00316 
00317   s = (const unsigned char*) _dbus_string_get_const_data (&bytes);
00318       
00319   id = s[0] | (s[1] << 8) | (s[2] << 16) | (s[3] << 24);
00320   if (id < 0)
00321     id = - id;
00322   _dbus_assert (id >= 0);
00323 
00324   if (find_key_by_id (keys, n_keys, id) != NULL)
00325     {
00326       _dbus_string_set_length (&bytes, 0);
00327       _dbus_verbose ("Key ID %d already existed, trying another one\n",
00328                      id);
00329       goto retry;
00330     }
00331 
00332   _dbus_verbose ("Creating key with ID %d\n", id);
00333       
00334 #define KEY_LENGTH_BYTES 24
00335   _dbus_string_set_length (&bytes, 0);
00336   if (!_dbus_generate_random_bytes (&bytes, KEY_LENGTH_BYTES))
00337     {
00338       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00339       goto out;
00340     }
00341 
00342   new = dbus_realloc (keys, sizeof (DBusKey) * (n_keys + 1));
00343   if (new == NULL)
00344     {
00345       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00346       goto out;
00347     }
00348 
00349   keys = new;
00350   *keys_p = keys; /* otherwise *keys_p ends up invalid */
00351   n_keys += 1;
00352 
00353   if (!_dbus_string_init (&keys[n_keys-1].secret))
00354     {
00355       n_keys -= 1; /* we don't want to free the one we didn't init */
00356       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00357       goto out;
00358     }
00359 
00360   _dbus_get_current_time (&timestamp, NULL);
00361       
00362   keys[n_keys-1].id = id;
00363   keys[n_keys-1].creation_time = timestamp;
00364   if (!_dbus_string_move (&bytes, 0,
00365                           &keys[n_keys-1].secret,
00366                           0))
00367     {
00368       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00369       _dbus_string_free (&keys[n_keys-1].secret);
00370       n_keys -= 1;
00371       goto out;
00372     }
00373   
00374   retval = TRUE;
00375   
00376  out:
00377   *n_keys_p = n_keys;
00378   
00379   _dbus_string_free (&bytes);
00380   return retval;
00381 }
00382 
00397 static dbus_bool_t
00398 _dbus_keyring_reload (DBusKeyring *keyring,
00399                       dbus_bool_t  add_new,
00400                       DBusError   *error)
00401 {
00402   DBusString contents;
00403   DBusString line;
00404   dbus_bool_t retval;
00405   dbus_bool_t have_lock;
00406   DBusKey *keys;
00407   int n_keys;
00408   int i;
00409   long now;
00410   DBusError tmp_error;
00411 
00412   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00413   
00414   if (!_dbus_check_dir_is_private_to_user (&keyring->directory, error))
00415     return FALSE;
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 - 1 : MAX_KEYS_IN_FILE))
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_INT32_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 ? error->message : "(unknown)");
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       if (keyring->credentials)
00692         _dbus_credentials_unref (keyring->credentials);
00693 
00694       _dbus_string_free (&keyring->filename);
00695       _dbus_string_free (&keyring->filename_lock);
00696       _dbus_string_free (&keyring->directory);
00697       free_keys (keyring->keys, keyring->n_keys);
00698       dbus_free (keyring);      
00699     }
00700 }
00701 
00712 DBusKeyring*
00713 _dbus_keyring_new_for_credentials (DBusCredentials  *credentials,
00714                                    const DBusString *context,
00715                                    DBusError        *error)
00716 {
00717   DBusString ringdir;
00718   DBusKeyring *keyring;
00719   dbus_bool_t error_set;
00720   DBusError tmp_error;
00721   DBusCredentials *our_credentials;
00722   
00723   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00724   
00725   keyring = NULL;
00726   error_set = FALSE;
00727   our_credentials = NULL;
00728   
00729   if (!_dbus_string_init (&ringdir))
00730     {
00731       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00732       return NULL;
00733     }
00734 
00735   if (credentials != NULL)
00736     {
00737       our_credentials = _dbus_credentials_copy (credentials);
00738     }
00739   else
00740     {
00741       our_credentials = _dbus_credentials_new_from_current_process ();
00742     }
00743   
00744   if (our_credentials == NULL)
00745     goto failed;
00746 
00747   if (_dbus_credentials_are_anonymous (our_credentials))
00748     {
00749       if (!_dbus_credentials_add_from_current_process (our_credentials))
00750         goto failed;
00751     }
00752   
00753   if (!_dbus_append_keyring_directory_for_credentials (&ringdir,
00754                                                        our_credentials))
00755     goto failed;
00756   
00757   keyring = _dbus_keyring_new ();
00758   if (keyring == NULL)
00759     goto failed;
00760 
00761   _dbus_assert (keyring->credentials == NULL);
00762   keyring->credentials = our_credentials;
00763   our_credentials = NULL; /* so we don't unref it again later */
00764   
00765   /* should have been validated already, but paranoia check here */
00766   if (!_dbus_keyring_validate_context (context))
00767     {
00768       error_set = TRUE;
00769       dbus_set_error_const (error,
00770                             DBUS_ERROR_FAILED,
00771                             "Invalid context in keyring creation");
00772       goto failed;
00773     }
00774 
00775   /* Save keyring dir in the keyring object */
00776   if (!_dbus_string_copy (&ringdir, 0,
00777                           &keyring->directory, 0))
00778     goto failed;  
00779 
00780   /* Create keyring->filename based on keyring dir and context */
00781   if (!_dbus_string_copy (&keyring->directory, 0,
00782                           &keyring->filename, 0))
00783     goto failed;
00784 
00785   if (!_dbus_concat_dir_and_file (&keyring->filename,
00786                                   context))
00787     goto failed;
00788 
00789   /* Create lockfile name */
00790   if (!_dbus_string_copy (&keyring->filename, 0,
00791                           &keyring->filename_lock, 0))
00792     goto failed;
00793 
00794   if (!_dbus_string_append (&keyring->filename_lock, ".lock"))
00795     goto failed;
00796 
00797   /* Reload keyring */
00798   dbus_error_init (&tmp_error);
00799   if (!_dbus_keyring_reload (keyring, FALSE, &tmp_error))
00800     {
00801       _dbus_verbose ("didn't load an existing keyring: %s\n",
00802                      tmp_error.message);
00803       dbus_error_free (&tmp_error);
00804     }
00805   
00806   /* We don't fail fatally if we can't create the directory,
00807    * but the keyring will probably always be empty
00808    * unless someone else manages to create it
00809    */
00810   dbus_error_init (&tmp_error);
00811   if (!_dbus_create_directory (&keyring->directory,
00812                                &tmp_error))
00813     {
00814       _dbus_verbose ("Creating keyring directory: %s\n",
00815                      tmp_error.message);
00816       dbus_error_free (&tmp_error);
00817     }
00818 
00819   _dbus_string_free (&ringdir);
00820   
00821   return keyring;
00822   
00823  failed:
00824   if (!error_set)
00825     dbus_set_error_const (error,
00826                           DBUS_ERROR_NO_MEMORY,
00827                           NULL);
00828   if (our_credentials)
00829     _dbus_credentials_unref (our_credentials);
00830   if (keyring)
00831     _dbus_keyring_unref (keyring);
00832   _dbus_string_free (&ringdir);
00833   return NULL;
00834 
00835 }
00836 
00849 dbus_bool_t
00850 _dbus_keyring_validate_context (const DBusString *context)
00851 {
00852   if (_dbus_string_get_length (context) == 0)
00853     {
00854       _dbus_verbose ("context is zero-length\n");
00855       return FALSE;
00856     }
00857 
00858   if (!_dbus_string_validate_ascii (context, 0,
00859                                     _dbus_string_get_length (context)))
00860     {
00861       _dbus_verbose ("context not valid ascii\n");
00862       return FALSE;
00863     }
00864   
00865   /* no directory separators */  
00866   if (_dbus_string_find (context, 0, "/", NULL))
00867     {
00868       _dbus_verbose ("context contains a slash\n");
00869       return FALSE;
00870     }
00871 
00872   if (_dbus_string_find (context, 0, "\\", NULL))
00873     {
00874       _dbus_verbose ("context contains a backslash\n");
00875       return FALSE;
00876     }
00877 
00878   /* prevent attempts to use dotfiles or ".." or ".lock"
00879    * all of which might allow some kind of attack
00880    */
00881   if (_dbus_string_find (context, 0, ".", NULL))
00882     {
00883       _dbus_verbose ("context contains a dot\n");
00884       return FALSE;
00885     }
00886 
00887   /* no spaces/tabs, those are used for separators in the protocol */
00888   if (_dbus_string_find_blank (context, 0, NULL))
00889     {
00890       _dbus_verbose ("context contains a blank\n");
00891       return FALSE;
00892     }
00893 
00894   if (_dbus_string_find (context, 0, "\n", NULL))
00895     {
00896       _dbus_verbose ("context contains a newline\n");
00897       return FALSE;
00898     }
00899 
00900   if (_dbus_string_find (context, 0, "\r", NULL))
00901     {
00902       _dbus_verbose ("context contains a carriage return\n");
00903       return FALSE;
00904     }
00905   
00906   return TRUE;
00907 }
00908 
00909 static DBusKey*
00910 find_recent_key (DBusKeyring *keyring)
00911 {
00912   int i;
00913   long tv_sec, tv_usec;
00914 
00915   _dbus_get_current_time (&tv_sec, &tv_usec);
00916   
00917   i = 0;
00918   while (i < keyring->n_keys)
00919     {
00920       DBusKey *key = &keyring->keys[i];
00921 
00922       _dbus_verbose ("Key %d is %ld seconds old\n",
00923                      i, tv_sec - key->creation_time);
00924       
00925       if ((tv_sec - NEW_KEY_TIMEOUT_SECONDS) < key->creation_time)
00926         return key;
00927       
00928       ++i;
00929     }
00930 
00931   return NULL;
00932 }
00933 
00945 int
00946 _dbus_keyring_get_best_key (DBusKeyring  *keyring,
00947                             DBusError    *error)
00948 {
00949   DBusKey *key;
00950 
00951   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00952   
00953   key = find_recent_key (keyring);
00954   if (key)
00955     return key->id;
00956 
00957   /* All our keys are too old, or we've never loaded the
00958    * keyring. Create a new one.
00959    */
00960   if (!_dbus_keyring_reload (keyring, TRUE,
00961                              error))
00962     return -1;
00963 
00964   key = find_recent_key (keyring);
00965   if (key)
00966     return key->id;
00967   else
00968     {
00969       dbus_set_error_const (error,
00970                             DBUS_ERROR_FAILED,
00971                             "No recent-enough key found in keyring, and unable to create a new key");
00972       return -1;
00973     }
00974 }
00975 
00984 dbus_bool_t
00985 _dbus_keyring_is_for_credentials (DBusKeyring           *keyring,
00986                                   DBusCredentials       *credentials)
00987 {
00988   return _dbus_credentials_same_user (keyring->credentials,
00989                                       credentials);
00990 }
00991 
01003 dbus_bool_t
01004 _dbus_keyring_get_hex_key (DBusKeyring       *keyring,
01005                            int                key_id,
01006                            DBusString        *hex_key)
01007 {
01008   DBusKey *key;
01009 
01010   key = find_key_by_id (keyring->keys,
01011                         keyring->n_keys,
01012                         key_id);
01013   if (key == NULL)
01014     return TRUE; /* had enough memory, so TRUE */
01015 
01016   return _dbus_string_hex_encode (&key->secret, 0,
01017                                   hex_key,
01018                                   _dbus_string_get_length (hex_key));
01019 }
01020  /* end of exposed API */
01022 
01023 #ifdef DBUS_BUILD_TESTS
01024 #include "dbus-test.h"
01025 #include <stdio.h>
01026 
01027 dbus_bool_t
01028 _dbus_keyring_test (void)
01029 {
01030   DBusString context;
01031   DBusKeyring *ring1;
01032   DBusKeyring *ring2;
01033   int id;
01034   DBusError error;
01035   int i;
01036 
01037   ring1 = NULL;
01038   ring2 = NULL;
01039   
01040   /* Context validation */
01041   
01042   _dbus_string_init_const (&context, "foo");
01043   _dbus_assert (_dbus_keyring_validate_context (&context));
01044   _dbus_string_init_const (&context, "org_freedesktop_blah");
01045   _dbus_assert (_dbus_keyring_validate_context (&context));
01046   
01047   _dbus_string_init_const (&context, "");
01048   _dbus_assert (!_dbus_keyring_validate_context (&context));
01049   _dbus_string_init_const (&context, ".foo");
01050   _dbus_assert (!_dbus_keyring_validate_context (&context));
01051   _dbus_string_init_const (&context, "bar.foo");
01052   _dbus_assert (!_dbus_keyring_validate_context (&context));
01053   _dbus_string_init_const (&context, "bar/foo");
01054   _dbus_assert (!_dbus_keyring_validate_context (&context));
01055   _dbus_string_init_const (&context, "bar\\foo");
01056   _dbus_assert (!_dbus_keyring_validate_context (&context));
01057   _dbus_string_init_const (&context, "foo\xfa\xf0");
01058   _dbus_assert (!_dbus_keyring_validate_context (&context));
01059   _dbus_string_init_const (&context, "foo\x80");
01060   _dbus_assert (!_dbus_keyring_validate_context (&context));
01061   _dbus_string_init_const (&context, "foo\x7f");
01062   _dbus_assert (_dbus_keyring_validate_context (&context));
01063   _dbus_string_init_const (&context, "foo bar");
01064   _dbus_assert (!_dbus_keyring_validate_context (&context));
01065   
01066   if (!_dbus_string_init (&context))
01067     _dbus_assert_not_reached ("no memory");
01068   if (!_dbus_string_append_byte (&context, '\0'))
01069     _dbus_assert_not_reached ("no memory");
01070   _dbus_assert (!_dbus_keyring_validate_context (&context));
01071   _dbus_string_free (&context);
01072 
01073   /* Now verify that if we create a key in keyring 1,
01074    * it is properly loaded in keyring 2
01075    */
01076 
01077   _dbus_string_init_const (&context, "org_freedesktop_dbus_testsuite");
01078   dbus_error_init (&error);
01079   ring1 = _dbus_keyring_new_for_credentials (NULL, &context,
01080                                              &error);
01081   _dbus_assert (ring1);
01082   _dbus_assert (error.name == NULL);
01083 
01084   id = _dbus_keyring_get_best_key (ring1, &error);
01085   if (id < 0)
01086     {
01087       fprintf (stderr, "Could not load keyring: %s\n", error.message);
01088       dbus_error_free (&error);
01089       goto failure;
01090     }
01091 
01092   ring2 = _dbus_keyring_new_for_credentials (NULL, &context, &error);
01093   _dbus_assert (ring2);
01094   _dbus_assert (error.name == NULL);
01095   
01096   if (ring1->n_keys != ring2->n_keys)
01097     {
01098       fprintf (stderr, "Different number of keys in keyrings\n");
01099       goto failure;
01100     }
01101 
01102   /* We guarantee we load and save keeping keys in a fixed
01103    * order
01104    */
01105   i = 0;
01106   while (i < ring1->n_keys)
01107     {
01108       if (ring1->keys[i].id != ring2->keys[i].id)
01109         {
01110           fprintf (stderr, "Keyring 1 has first key ID %d and keyring 2 has %d\n",
01111                    ring1->keys[i].id, ring2->keys[i].id);
01112           goto failure;
01113         }      
01114 
01115       if (ring1->keys[i].creation_time != ring2->keys[i].creation_time)
01116         {
01117           fprintf (stderr, "Keyring 1 has first key time %ld and keyring 2 has %ld\n",
01118                    ring1->keys[i].creation_time, ring2->keys[i].creation_time);
01119           goto failure;
01120         }
01121 
01122       if (!_dbus_string_equal (&ring1->keys[i].secret,
01123                                &ring2->keys[i].secret))
01124         {
01125           fprintf (stderr, "Keyrings 1 and 2 have different secrets for same ID/timestamp\n");
01126           goto failure;
01127         }
01128       
01129       ++i;
01130     }
01131 
01132   printf (" %d keys in test\n", ring1->n_keys);
01133 
01134   /* Test ref/unref */
01135   _dbus_keyring_ref (ring1);
01136   _dbus_keyring_ref (ring2);
01137   _dbus_keyring_unref (ring1);
01138   _dbus_keyring_unref (ring2);
01139 
01140 
01141   /* really unref */
01142   _dbus_keyring_unref (ring1);
01143   _dbus_keyring_unref (ring2);
01144   
01145   return TRUE;
01146 
01147  failure:
01148   if (ring1)
01149     _dbus_keyring_unref (ring1);
01150   if (ring2)
01151     _dbus_keyring_unref (ring2);
01152 
01153   return FALSE;
01154 }
01155 
01156 #endif /* DBUS_BUILD_TESTS */
01157      

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