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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, 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-userdb.h"
00026 #include "dbus-protocol.h"
00027 #include <dbus/dbus-string.h>
00028 #include <dbus/dbus-list.h>
00029 #include <dbus/dbus-sysdeps.h>
00030 
00067 #define NEW_KEY_TIMEOUT_SECONDS     (60*5)
00068 
00073 #define EXPIRE_KEYS_TIMEOUT_SECONDS (NEW_KEY_TIMEOUT_SECONDS + (60*2))
00074 
00077 #define MAX_TIME_TRAVEL_SECONDS (60*5)
00078 
00083 #ifdef DBUS_BUILD_TESTS
00084 #define MAX_KEYS_IN_FILE 10
00085 #else
00086 #define MAX_KEYS_IN_FILE 256
00087 #endif
00088 
00092 typedef struct
00093 {
00094   dbus_int32_t id; 
00096   long creation_time; 
00101   DBusString secret; 
00103 } DBusKey;
00104 
00111 struct DBusKeyring
00112 {
00113   int refcount;             
00114   DBusString username;      
00115   DBusString directory;     
00116   DBusString filename;      
00117   DBusString filename_lock; 
00118   DBusKey *keys; 
00119   int n_keys;    
00120 };
00121 
00122 static DBusKeyring*
00123 _dbus_keyring_new (void)
00124 {
00125   DBusKeyring *keyring;
00126 
00127   keyring = dbus_new0 (DBusKeyring, 1);
00128   if (keyring == NULL)
00129     goto out_0;
00130   
00131   if (!_dbus_string_init (&keyring->directory))
00132     goto out_1;
00133 
00134   if (!_dbus_string_init (&keyring->filename))
00135     goto out_2;
00136 
00137   if (!_dbus_string_init (&keyring->filename_lock))
00138     goto out_3;
00139 
00140   if (!_dbus_string_init (&keyring->username))
00141     goto out_4;
00142   
00143   keyring->refcount = 1;
00144   keyring->keys = NULL;
00145   keyring->n_keys = 0;
00146 
00147   return keyring;
00148 
00149  out_4:
00150   _dbus_string_free (&keyring->filename_lock);
00151  out_3:
00152   _dbus_string_free (&keyring->filename);
00153  out_2:
00154   _dbus_string_free (&keyring->directory);
00155  out_1:
00156   dbus_free (keyring);
00157  out_0:
00158   return NULL;
00159 }
00160 
00161 static void
00162 free_keys (DBusKey *keys,
00163            int      n_keys)
00164 {
00165   int i;
00166 
00167   /* should be safe for args NULL, 0 */
00168   
00169   i = 0;
00170   while (i < n_keys)
00171     {
00172       _dbus_string_free (&keys[i].secret);
00173       ++i;
00174     }
00175 
00176   dbus_free (keys);
00177 }
00178 
00179 /* Our locking scheme is highly unreliable.  However, there is
00180  * unfortunately no reliable locking scheme in user home directories;
00181  * between bugs in Linux NFS, people using Tru64 or other total crap
00182  * NFS, AFS, random-file-system-of-the-week, and so forth, fcntl() in
00183  * homedirs simply generates tons of bug reports. This has been
00184  * learned through hard experience with GConf, unfortunately.
00185  *
00186  * This bad hack might work better for the kind of lock we have here,
00187  * which we don't expect to hold for any length of time.  Crashing
00188  * while we hold it should be unlikely, and timing out such that we
00189  * delete a stale lock should also be unlikely except when the
00190  * filesystem is running really slowly.  Stuff might break in corner
00191  * cases but as long as it's not a security-level breakage it should
00192  * be OK.
00193  */
00194 
00196 #define MAX_LOCK_TIMEOUTS 32
00197 
00198 #define LOCK_TIMEOUT_MILLISECONDS 250
00199 
00200 static dbus_bool_t
00201 _dbus_keyring_lock (DBusKeyring *keyring)
00202 {
00203   int n_timeouts;
00204   
00205   n_timeouts = 0;
00206   while (n_timeouts < MAX_LOCK_TIMEOUTS)
00207     {
00208       DBusError error;
00209 
00210       dbus_error_init (&error);
00211       if (_dbus_create_file_exclusively (&keyring->filename_lock,
00212                                          &error))
00213         break;
00214 
00215       _dbus_verbose ("Did not get lock file, sleeping %d milliseconds (%s)\n",
00216                      LOCK_TIMEOUT_MILLISECONDS, error.message);
00217       dbus_error_free (&error);
00218 
00219       _dbus_sleep_milliseconds (LOCK_TIMEOUT_MILLISECONDS);
00220       
00221       ++n_timeouts;
00222     }
00223 
00224   if (n_timeouts == MAX_LOCK_TIMEOUTS)
00225     {
00226       DBusError error;
00227       
00228       _dbus_verbose ("Lock file timed out %d times, assuming stale\n",
00229                      n_timeouts);
00230 
00231       dbus_error_init (&error);
00232 
00233       if (!_dbus_delete_file (&keyring->filename_lock, &error))
00234         {
00235           _dbus_verbose ("Couldn't delete old lock file: %s\n",
00236                          error.message);
00237           dbus_error_free (&error);
00238           return FALSE;
00239         }
00240 
00241       if (!_dbus_create_file_exclusively (&keyring->filename_lock,
00242                                           &error))
00243         {
00244           _dbus_verbose ("Couldn't create lock file after deleting stale one: %s\n",
00245                          error.message);
00246           dbus_error_free (&error);
00247           return FALSE;
00248         }
00249     }
00250   
00251   return TRUE;
00252 }
00253 
00254 static void
00255 _dbus_keyring_unlock (DBusKeyring *keyring)
00256 {
00257   DBusError error;
00258   dbus_error_init (&error);
00259   if (!_dbus_delete_file (&keyring->filename_lock, &error))
00260     {
00261       _dbus_warn ("Failed to delete lock file: %s\n",
00262                   error.message);
00263       dbus_error_free (&error);
00264     }
00265 }
00266 
00267 static DBusKey*
00268 find_key_by_id (DBusKey *keys,
00269                 int      n_keys,
00270                 int      id)
00271 {
00272   int i;
00273 
00274   i = 0;
00275   while (i < n_keys)
00276     {
00277       if (keys[i].id == id)
00278         return &keys[i];
00279       
00280       ++i;
00281     }
00282 
00283   return NULL;
00284 }
00285 
00286 static dbus_bool_t
00287 add_new_key (DBusKey  **keys_p,
00288              int       *n_keys_p,
00289              DBusError *error)
00290 {
00291   DBusKey *new;
00292   DBusString bytes;
00293   int id;
00294   long timestamp;
00295   const unsigned char *s;
00296   dbus_bool_t retval;
00297   DBusKey *keys;
00298   int n_keys;
00299 
00300   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00301   
00302   if (!_dbus_string_init (&bytes))
00303     {
00304       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00305       return FALSE;
00306     }
00307 
00308   keys = *keys_p;
00309   n_keys = *n_keys_p;
00310   retval = FALSE;
00311       
00312   /* Generate an integer ID and then the actual key. */
00313  retry:
00314       
00315   if (!_dbus_generate_random_bytes (&bytes, 4))
00316     {
00317       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00318       goto out;
00319     }
00320 
00321   s = (const unsigned char*) _dbus_string_get_const_data (&bytes);
00322       
00323   id = s[0] | (s[1] << 8) | (s[2] << 16) | (s[3] << 24);
00324   if (id < 0)
00325     id = - id;
00326   _dbus_assert (id >= 0);
00327 
00328   if (find_key_by_id (keys, n_keys, id) != NULL)
00329     {
00330       _dbus_string_set_length (&bytes, 0);
00331       _dbus_verbose ("Key ID %d already existed, trying another one\n",
00332                      id);
00333       goto retry;
00334     }
00335 
00336   _dbus_verbose ("Creating key with ID %d\n", id);
00337       
00338 #define KEY_LENGTH_BYTES 24
00339   _dbus_string_set_length (&bytes, 0);
00340   if (!_dbus_generate_random_bytes (&bytes, KEY_LENGTH_BYTES))
00341     {
00342       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00343       goto out;
00344     }
00345 
00346   new = dbus_realloc (keys, sizeof (DBusKey) * (n_keys + 1));
00347   if (new == NULL)
00348     {
00349       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00350       goto out;
00351     }
00352 
00353   keys = new;
00354   *keys_p = keys; /* otherwise *keys_p ends up invalid */
00355   n_keys += 1;
00356 
00357   if (!_dbus_string_init (&keys[n_keys-1].secret))
00358     {
00359       n_keys -= 1; /* we don't want to free the one we didn't init */
00360       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00361       goto out;
00362     }
00363 
00364   _dbus_get_current_time (&timestamp, NULL);
00365       
00366   keys[n_keys-1].id = id;
00367   keys[n_keys-1].creation_time = timestamp;
00368   if (!_dbus_string_move (&bytes, 0,
00369                           &keys[n_keys-1].secret,
00370                           0))
00371     {
00372       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00373       _dbus_string_free (&keys[n_keys-1].secret);
00374       n_keys -= 1;
00375       goto out;
00376     }
00377   
00378   retval = TRUE;
00379   
00380  out:
00381   *n_keys_p = n_keys;
00382   
00383   _dbus_string_free (&bytes);
00384   return retval;
00385 }
00386 
00401 static dbus_bool_t
00402 _dbus_keyring_reload (DBusKeyring *keyring,
00403                       dbus_bool_t  add_new,
00404                       DBusError   *error)
00405 {
00406   DBusString contents;
00407   DBusString line;
00408   dbus_bool_t retval;
00409   dbus_bool_t have_lock;
00410   DBusKey *keys;
00411   int n_keys;
00412   int i;
00413   long now;
00414   DBusError tmp_error;
00415 
00416   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00417   
00418   if (!_dbus_string_init (&contents))
00419     {
00420       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00421       return FALSE;
00422     }
00423 
00424   if (!_dbus_string_init (&line))
00425     {
00426       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00427       _dbus_string_free (&contents);
00428       return FALSE;
00429     }
00430 
00431   keys = NULL;
00432   n_keys = 0;
00433   retval = FALSE;
00434   have_lock = FALSE;
00435 
00436   _dbus_get_current_time (&now, NULL);
00437   
00438   if (add_new)
00439     {
00440       if (!_dbus_keyring_lock (keyring))
00441         {
00442           dbus_set_error (error, DBUS_ERROR_FAILED,
00443                           "Could not lock keyring file to add to it");
00444           goto out;
00445         }
00446 
00447       have_lock = TRUE;
00448     }
00449 
00450   dbus_error_init (&tmp_error);
00451   if (!_dbus_file_get_contents (&contents, 
00452                                 &keyring->filename,
00453                                 &tmp_error))
00454     {
00455       _dbus_verbose ("Failed to load keyring file: %s\n",
00456                      tmp_error.message);
00457       /* continue with empty keyring file, so we recreate it */
00458       dbus_error_free (&tmp_error);
00459     }
00460 
00461   if (!_dbus_string_validate_ascii (&contents, 0,
00462                                     _dbus_string_get_length (&contents)))
00463     {
00464       _dbus_warn ("Secret keyring file contains non-ASCII! Ignoring existing contents\n");
00465       _dbus_string_set_length (&contents, 0);
00466     }
00467 
00468   /* FIXME this is badly inefficient for large keyring files
00469    * (not that large keyring files exist outside of test suites)
00470    */
00471   while (_dbus_string_pop_line (&contents, &line))
00472     {
00473       int next;
00474       long val;
00475       int id;
00476       long timestamp;
00477       int len;
00478       int end;
00479       DBusKey *new;
00480 
00481       /* Don't load more than the max. */
00482       if (n_keys >= (add_new ? MAX_KEYS_IN_FILE : MAX_KEYS_IN_FILE - 1))
00483         break;
00484       
00485       next = 0;
00486       if (!_dbus_string_parse_int (&line, 0, &val, &next))
00487         {
00488           _dbus_verbose ("could not parse secret key ID at start of line\n");
00489           continue;
00490         }
00491 
00492       if (val > _DBUS_INT_MAX || val < 0)
00493         {
00494           _dbus_verbose ("invalid secret key ID at start of line\n");
00495           continue;
00496         }
00497       
00498       id = val;
00499 
00500       _dbus_string_skip_blank (&line, next, &next);
00501       
00502       if (!_dbus_string_parse_int (&line, next, &timestamp, &next))
00503         {
00504           _dbus_verbose ("could not parse secret key timestamp\n");
00505           continue;
00506         }
00507 
00508       if (timestamp < 0 ||
00509           (now + MAX_TIME_TRAVEL_SECONDS) < timestamp ||
00510           (now - EXPIRE_KEYS_TIMEOUT_SECONDS) > timestamp)
00511         {
00512           _dbus_verbose ("dropping/ignoring %ld-seconds old key with timestamp %ld as current time is %ld\n",
00513                          now - timestamp, timestamp, now);
00514           continue;
00515         }
00516       
00517       _dbus_string_skip_blank (&line, next, &next);
00518 
00519       len = _dbus_string_get_length (&line);
00520 
00521       if ((len - next) == 0)
00522         {
00523           _dbus_verbose ("no secret key after ID and timestamp\n");
00524           continue;
00525         }
00526       
00527       /* We have all three parts */
00528       new = dbus_realloc (keys, sizeof (DBusKey) * (n_keys + 1));
00529       if (new == NULL)
00530         {
00531           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00532           goto out;
00533         }
00534 
00535       keys = new;
00536       n_keys += 1;
00537 
00538       if (!_dbus_string_init (&keys[n_keys-1].secret))
00539         {
00540           n_keys -= 1; /* we don't want to free the one we didn't init */
00541           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00542           goto out;
00543         }
00544       
00545       keys[n_keys-1].id = id;
00546       keys[n_keys-1].creation_time = timestamp;
00547       if (!_dbus_string_hex_decode (&line, next, &end,
00548                                     &keys[n_keys-1].secret, 0))
00549         {
00550           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00551           goto out;
00552         }
00553 
00554       if (_dbus_string_get_length (&line) != end)
00555         {
00556           _dbus_verbose ("invalid hex encoding in keyring file\n");
00557           _dbus_string_free (&keys[n_keys - 1].secret);
00558           n_keys -= 1;
00559           continue;
00560         }
00561     }
00562 
00563   _dbus_verbose ("Successfully loaded %d existing keys\n",
00564                  n_keys);
00565 
00566   if (add_new)
00567     {
00568       if (!add_new_key (&keys, &n_keys, error))
00569         {
00570           _dbus_verbose ("Failed to generate new key: %s\n",
00571                          error ? "(unknown)" : error->message);
00572           goto out;
00573         }
00574 
00575       _dbus_string_set_length (&contents, 0);
00576 
00577       i = 0;
00578       while (i < n_keys)
00579         {
00580           if (!_dbus_string_append_int (&contents,
00581                                         keys[i].id))
00582             goto nomem;
00583 
00584           if (!_dbus_string_append_byte (&contents, ' '))
00585             goto nomem;
00586 
00587           if (!_dbus_string_append_int (&contents,
00588                                         keys[i].creation_time))
00589             goto nomem;
00590 
00591           if (!_dbus_string_append_byte (&contents, ' '))
00592             goto nomem;
00593 
00594           if (!_dbus_string_hex_encode (&keys[i].secret, 0,
00595                                         &contents,
00596                                         _dbus_string_get_length (&contents)))
00597             goto nomem;
00598 
00599           if (!_dbus_string_append_byte (&contents, '\n'))
00600             goto nomem;          
00601           
00602           ++i;
00603           continue;
00604 
00605         nomem:
00606           dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00607           goto out;
00608         }
00609       
00610       if (!_dbus_string_save_to_file (&contents, &keyring->filename,
00611                                       error))
00612         goto out;
00613     }
00614 
00615   if (keyring->keys)
00616     free_keys (keyring->keys, keyring->n_keys);
00617   keyring->keys = keys;
00618   keyring->n_keys = n_keys;
00619   keys = NULL;
00620   n_keys = 0;
00621   
00622   retval = TRUE;  
00623   
00624  out:
00625   if (have_lock)
00626     _dbus_keyring_unlock (keyring);
00627   
00628   if (! ((retval == TRUE && (error == NULL || error->name == NULL)) ||
00629          (retval == FALSE && (error == NULL || error->name != NULL))))
00630     {
00631       if (error && error->name)
00632         _dbus_verbose ("error is %s: %s\n", error->name, error->message);
00633       _dbus_warn ("returning %d but error pointer %p name %s\n",
00634                   retval, error, error->name ? error->name : "(none)");
00635       _dbus_assert_not_reached ("didn't handle errors properly");
00636     }
00637   
00638   if (keys != NULL)
00639     {
00640       i = 0;
00641       while (i < n_keys)
00642         {
00643           _dbus_string_zero (&keys[i].secret);
00644           _dbus_string_free (&keys[i].secret);
00645           ++i;
00646         }
00647 
00648       dbus_free (keys);
00649     }
00650   
00651   _dbus_string_free (&contents);
00652   _dbus_string_free (&line);
00653 
00654   return retval;
00655 }
00656  /* end of internals */
00658 
00671 DBusKeyring *
00672 _dbus_keyring_ref (DBusKeyring *keyring)
00673 {
00674   keyring->refcount += 1;
00675 
00676   return keyring;
00677 }
00678 
00685 void
00686 _dbus_keyring_unref (DBusKeyring *keyring)
00687 {
00688   keyring->refcount -= 1;
00689 
00690   if (keyring->refcount == 0)
00691     {
00692       _dbus_string_free (&keyring->username);
00693       _dbus_string_free (&keyring->filename);
00694       _dbus_string_free (&keyring->filename_lock);
00695       _dbus_string_free (&keyring->directory);
00696       free_keys (keyring->keys, keyring->n_keys);
00697       dbus_free (keyring);      
00698     }
00699 }
00700 
00711 DBusKeyring*
00712 _dbus_keyring_new_homedir (const DBusString *username,
00713                            const DBusString *context,
00714                            DBusError        *error)
00715 {
00716   DBusString homedir;
00717   DBusKeyring *keyring;
00718   dbus_bool_t error_set;
00719   DBusString dotdir;
00720   DBusError tmp_error;
00721 
00722   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00723   
00724   keyring = NULL;
00725   error_set = FALSE;
00726   
00727   if (!_dbus_string_init (&homedir))
00728     {
00729       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00730       return FALSE;
00731     }
00732 
00733   _dbus_string_init_const (&dotdir, ".dbus-keyrings");
00734   
00735   if (username == NULL)
00736     {
00737       const DBusString *const_homedir;
00738 
00739       if (!_dbus_username_from_current_process (&username) ||
00740           !_dbus_homedir_from_current_process (&const_homedir))
00741         goto failed;
00742 
00743       if (!_dbus_string_copy (const_homedir, 0,
00744                               &homedir, 0))
00745         goto failed;
00746     }
00747   else
00748     {
00749       if (!_dbus_homedir_from_username (username, &homedir))
00750         goto failed;
00751     }
00752 
00753 #ifdef DBUS_BUILD_TESTS
00754  {
00755    const char *override;
00756 
00757    override = _dbus_getenv ("DBUS_TEST_HOMEDIR");
00758    if (override != NULL && *override != '\0')
00759      {
00760        _dbus_string_set_length (&homedir, 0);
00761        if (!_dbus_string_append (&homedir, override))
00762          goto failed;
00763 
00764        _dbus_verbose ("Using fake homedir for testing: %s\n",
00765                       _dbus_string_get_const_data (&homedir));
00766      }
00767    else
00768      {
00769        static dbus_bool_t already_warned = FALSE;
00770        if (!already_warned)
00771          {
00772            _dbus_warn ("Using your real home directory for testing, set DBUS_TEST_HOMEDIR to avoid\n");
00773            already_warned = TRUE;
00774          }
00775      }
00776  }
00777 #endif
00778   
00779   _dbus_assert (username != NULL);    
00780   
00781   keyring = _dbus_keyring_new ();
00782   if (keyring == NULL)
00783     goto failed;
00784 
00785   /* should have been validated already, but paranoia check here */
00786   if (!_dbus_keyring_validate_context (context))
00787     {
00788       error_set = TRUE;
00789       dbus_set_error_const (error,
00790                             DBUS_ERROR_FAILED,
00791                             "Invalid context in keyring creation");
00792       goto failed;
00793     }
00794 
00795   if (!_dbus_string_copy (username, 0,
00796                           &keyring->username, 0))
00797     goto failed;
00798   
00799   if (!_dbus_string_copy (&homedir, 0,
00800                           &keyring->directory, 0))
00801     goto failed;
00802   
00803   if (!_dbus_concat_dir_and_file (&keyring->directory,
00804                                   &dotdir))
00805     goto failed;
00806 
00807   if (!_dbus_string_copy (&keyring->directory, 0,
00808                           &keyring->filename, 0))
00809     goto failed;
00810 
00811   if (!_dbus_concat_dir_and_file (&keyring->filename,
00812                                   context))
00813     goto failed;
00814 
00815   if (!_dbus_string_copy (&keyring->filename, 0,
00816                           &keyring->filename_lock, 0))
00817     goto failed;
00818 
00819   if (!_dbus_string_append (&keyring->filename_lock, ".lock"))
00820     goto failed;
00821 
00822   dbus_error_init (&tmp_error);
00823   if (!_dbus_keyring_reload (keyring, FALSE, &tmp_error))
00824     {
00825       _dbus_verbose ("didn't load an existing keyring: %s\n",
00826                      tmp_error.message);
00827       dbus_error_free (&tmp_error);
00828     }
00829   
00830   /* We don't fail fatally if we can't create the directory,
00831    * but the keyring will probably always be empty
00832    * unless someone else manages to create it
00833    */
00834   dbus_error_init (&tmp_error);
00835   if (!_dbus_create_directory (&keyring->directory,
00836                                &tmp_error))
00837     {
00838       _dbus_verbose ("Creating keyring directory: %s\n",
00839                      tmp_error.message);
00840       dbus_error_free (&tmp_error);
00841     }
00842 
00843   _dbus_string_free (&homedir);
00844   
00845   return keyring;
00846   
00847  failed:
00848   if (!error_set)
00849     dbus_set_error_const (error,
00850                           DBUS_ERROR_NO_MEMORY,
00851                           NULL);
00852   if (keyring)
00853     _dbus_keyring_unref (keyring);
00854   _dbus_string_free (&homedir);
00855   return FALSE;
00856 
00857 }
00858 
00871 dbus_bool_t
00872 _dbus_keyring_validate_context (const DBusString *context)
00873 {
00874   if (_dbus_string_get_length (context) == 0)
00875     {
00876       _dbus_verbose ("context is zero-length\n");
00877       return FALSE;
00878     }
00879 
00880   if (!_dbus_string_validate_ascii (context, 0,
00881                                     _dbus_string_get_length (context)))
00882     {
00883       _dbus_verbose ("context not valid ascii\n");
00884       return FALSE;
00885     }
00886   
00887   /* no directory separators */  
00888   if (_dbus_string_find (context, 0, "/", NULL))
00889     {
00890       _dbus_verbose ("context contains a slash\n");
00891       return FALSE;
00892     }
00893 
00894   if (_dbus_string_find (context, 0, "\\", NULL))
00895     {
00896       _dbus_verbose ("context contains a backslash\n");
00897       return FALSE;
00898     }
00899 
00900   /* prevent attempts to use dotfiles or ".." or ".lock"
00901    * all of which might allow some kind of attack
00902    */
00903   if (_dbus_string_find (context, 0, ".", NULL))
00904     {
00905       _dbus_verbose ("context contains a dot\n");
00906       return FALSE;
00907     }
00908 
00909   /* no spaces/tabs, those are used for separators in the protocol */
00910   if (_dbus_string_find_blank (context, 0, NULL))
00911     {
00912       _dbus_verbose ("context contains a blank\n");
00913       return FALSE;
00914     }
00915 
00916   if (_dbus_string_find (context, 0, "\n", NULL))
00917     {
00918       _dbus_verbose ("context contains a newline\n");
00919       return FALSE;
00920     }
00921 
00922   if (_dbus_string_find (context, 0, "\r", NULL))
00923     {
00924       _dbus_verbose ("context contains a carriage return\n");
00925       return FALSE;
00926     }
00927   
00928   return TRUE;
00929 }
00930 
00931 static DBusKey*
00932 find_recent_key (DBusKeyring *keyring)
00933 {
00934   int i;
00935   long tv_sec, tv_usec;
00936 
00937   _dbus_get_current_time (&tv_sec, &tv_usec);
00938   
00939   i = 0;
00940   while (i < keyring->n_keys)
00941     {
00942       DBusKey *key = &keyring->keys[i];
00943 
00944       _dbus_verbose ("Key %d is %ld seconds old\n",
00945                      i, tv_sec - key->creation_time);
00946       
00947       if ((tv_sec - NEW_KEY_TIMEOUT_SECONDS) < key->creation_time)
00948         return key;
00949       
00950       ++i;
00951     }
00952 
00953   return NULL;
00954 }
00955 
00967 int
00968 _dbus_keyring_get_best_key (DBusKeyring  *keyring,
00969                             DBusError    *error)
00970 {
00971   DBusKey *key;
00972 
00973   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
00974   
00975   key = find_recent_key (keyring);
00976   if (key)
00977     return key->id;
00978 
00979   /* All our keys are too old, or we've never loaded the
00980    * keyring. Create a new one.
00981    */
00982   if (!_dbus_keyring_reload (keyring, TRUE,
00983                              error))
00984     return -1;
00985 
00986   key = find_recent_key (keyring);
00987   if (key)
00988     return key->id;
00989   else
00990     {
00991       dbus_set_error_const (error,
00992                             DBUS_ERROR_FAILED,
00993                             "No recent-enough key found in keyring, and unable to create a new key");
00994       return -1;
00995     }
00996 }
00997 
01006 dbus_bool_t
01007 _dbus_keyring_is_for_user (DBusKeyring       *keyring,
01008                            const DBusString  *username)
01009 {
01010   return _dbus_string_equal (&keyring->username,
01011                              username);
01012 }
01013 
01025 dbus_bool_t
01026 _dbus_keyring_get_hex_key (DBusKeyring       *keyring,
01027                            int                key_id,
01028                            DBusString        *hex_key)
01029 {
01030   DBusKey *key;
01031 
01032   key = find_key_by_id (keyring->keys,
01033                         keyring->n_keys,
01034                         key_id);
01035   if (key == NULL)
01036     return TRUE; /* had enough memory, so TRUE */
01037 
01038   return _dbus_string_hex_encode (&key->secret, 0,
01039                                   hex_key,
01040                                   _dbus_string_get_length (hex_key));
01041 }
01042  /* end of exposed API */
01044 
01045 #ifdef DBUS_BUILD_TESTS
01046 #include "dbus-test.h"
01047 #include <stdio.h>
01048 
01049 dbus_bool_t
01050 _dbus_keyring_test (void)
01051 {
01052   DBusString context;
01053   DBusKeyring *ring1;
01054   DBusKeyring *ring2;
01055   int id;
01056   DBusError error;
01057   int i;
01058 
01059   ring1 = NULL;
01060   ring2 = NULL;
01061   
01062   /* Context validation */
01063   
01064   _dbus_string_init_const (&context, "foo");
01065   _dbus_assert (_dbus_keyring_validate_context (&context));
01066   _dbus_string_init_const (&context, "org_freedesktop_blah");
01067   _dbus_assert (_dbus_keyring_validate_context (&context));
01068   
01069   _dbus_string_init_const (&context, "");
01070   _dbus_assert (!_dbus_keyring_validate_context (&context));
01071   _dbus_string_init_const (&context, ".foo");
01072   _dbus_assert (!_dbus_keyring_validate_context (&context));
01073   _dbus_string_init_const (&context, "bar.foo");
01074   _dbus_assert (!_dbus_keyring_validate_context (&context));
01075   _dbus_string_init_const (&context, "bar/foo");
01076   _dbus_assert (!_dbus_keyring_validate_context (&context));
01077   _dbus_string_init_const (&context, "bar\\foo");
01078   _dbus_assert (!_dbus_keyring_validate_context (&context));
01079   _dbus_string_init_const (&context, "foo\xfa\xf0");
01080   _dbus_assert (!_dbus_keyring_validate_context (&context));
01081   _dbus_string_init_const (&context, "foo\x80");
01082   _dbus_assert (!_dbus_keyring_validate_context (&context));
01083   _dbus_string_init_const (&context, "foo\x7f");
01084   _dbus_assert (_dbus_keyring_validate_context (&context));
01085   _dbus_string_init_const (&context, "foo bar");
01086   _dbus_assert (!_dbus_keyring_validate_context (&context));
01087   
01088   if (!_dbus_string_init (&context))
01089     _dbus_assert_not_reached ("no memory");
01090   if (!_dbus_string_append_byte (&context, '\0'))
01091     _dbus_assert_not_reached ("no memory");
01092   _dbus_assert (!_dbus_keyring_validate_context (&context));
01093   _dbus_string_free (&context);
01094 
01095   /* Now verify that if we create a key in keyring 1,
01096    * it is properly loaded in keyring 2
01097    */
01098 
01099   _dbus_string_init_const (&context, "org_freedesktop_dbus_testsuite");
01100   dbus_error_init (&error);
01101   ring1 = _dbus_keyring_new_homedir (NULL, &context,
01102                                      &error);
01103   _dbus_assert (ring1);
01104   _dbus_assert (error.name == NULL);
01105 
01106   id = _dbus_keyring_get_best_key (ring1, &error);
01107   if (id < 0)
01108     {
01109       fprintf (stderr, "Could not load keyring: %s\n", error.message);
01110       dbus_error_free (&error);
01111       goto failure;
01112     }
01113 
01114   ring2 = _dbus_keyring_new_homedir (NULL, &context, &error);
01115   _dbus_assert (ring2);
01116   _dbus_assert (error.name == NULL);
01117   
01118   if (ring1->n_keys != ring2->n_keys)
01119     {
01120       fprintf (stderr, "Different number of keys in keyrings\n");
01121       goto failure;
01122     }
01123 
01124   /* We guarantee we load and save keeping keys in a fixed
01125    * order
01126    */
01127   i = 0;
01128   while (i < ring1->n_keys)
01129     {
01130       if (ring1->keys[i].id != ring2->keys[i].id)
01131         {
01132           fprintf (stderr, "Keyring 1 has first key ID %d and keyring 2 has %d\n",
01133                    ring1->keys[i].id, ring2->keys[i].id);
01134           goto failure;
01135         }      
01136 
01137       if (ring1->keys[i].creation_time != ring2->keys[i].creation_time)
01138         {
01139           fprintf (stderr, "Keyring 1 has first key time %ld and keyring 2 has %ld\n",
01140                    ring1->keys[i].creation_time, ring2->keys[i].creation_time);
01141           goto failure;
01142         }
01143 
01144       if (!_dbus_string_equal (&ring1->keys[i].secret,
01145                                &ring2->keys[i].secret))
01146         {
01147           fprintf (stderr, "Keyrings 1 and 2 have different secrets for same ID/timestamp\n");
01148           goto failure;
01149         }
01150       
01151       ++i;
01152     }
01153 
01154   printf (" %d keys in test\n", ring1->n_keys);
01155 
01156   /* Test ref/unref */
01157   _dbus_keyring_ref (ring1);
01158   _dbus_keyring_ref (ring2);
01159   _dbus_keyring_unref (ring1);
01160   _dbus_keyring_unref (ring2);
01161 
01162 
01163   /* really unref */
01164   _dbus_keyring_unref (ring1);
01165   _dbus_keyring_unref (ring2);
01166   
01167   return TRUE;
01168 
01169  failure:
01170   if (ring1)
01171     _dbus_keyring_unref (ring1);
01172   if (ring2)
01173     _dbus_keyring_unref (ring2);
01174 
01175   return FALSE;
01176 }
01177 
01178 #endif /* DBUS_BUILD_TESTS */
01179      

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