Console user security policy

* bus/config-parser.c:
(struct PolicyType): Add POLICY_CONSOLE
(struct Element.d.policy): s/gid_or_uid/gid_uid_or_at_console
(start_busconfig_child): Sets up console element when
<policy at_console=""> is encountered in a policy file
(append_rule_from_element): Convert console elements to console
rules.

* bus/policy.c:
(bus_policy_create_client_policy): Add console rules to the client
policy based on if the client is at the console
(bus_policy_append_console_rule): New function for adding a
console rule to a policy
(bus_policy_merge): Handle console rule merging

* dbus/dbus-sysdeps.h: Added the DBUS_CONSOLE_DIR constant
where we check for console user files

* dbus/dbus-sysdeps.c:
(_dbus_file_exists): New function which checks if the given
file exists
(_dbus_user_at_console): New function which does the system
specific process of checking if the user is at the console

* dbus/dbus-userdb.c:
(_dbus_is_console_user): New function converts a UID to user name
and then calls the system specific _dbus_user_at_console to
see if the user is at the console and therefor a console user

4 files changed, 99 insertions, 1 deletions

diff --git a/dbus/dbus-sysdeps.c b/dbus/dbus-sysdeps.c
index e5d4bdba..4af70931 100644
--- a/dbus/dbus-sysdeps.c
+++ b/dbus/dbus-sysdeps.c
@@ -3332,6 +3332,55 @@ _dbus_set_signal_handler (int               sig,
   sigaction (sig,  &act, 0);
 }
 
+/** Checks if a file exists
+*
+* @param file full path to the file
+* @returns #TRUE if file exists
+*/
+dbus_bool_t 
+_dbus_file_exists (const char *file)
+{
+  return (access (file, F_OK) == 0);
+}
+
+/** Checks if user is at the console
+*
+* @param username user to check
+* @param error return location for errors
+* @returns #TRUE is the user is at the consolei and there are no errors
+*/
+dbus_bool_t 
+_dbus_user_at_console (const char *username,
+                       DBusError  *error)
+{
+
+  DBusString f;
+  dbus_bool_t result;
+
+  if (!_dbus_string_init (&f))
+    {
+      dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
+      return FALSE;
+    }
+
+  if (!_dbus_string_append (&f, DBUS_CONSOLE_DIR))
+    {
+      dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
+      return FALSE;
+    }
+
+
+  if (!_dbus_string_append (&f, username))
+    {
+      dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
+      return FALSE;
+    }
+
+  result = _dbus_file_exists (_dbus_string_get_const_data (&f));
+  _dbus_string_free (&f);
+
+  return result;
+}
 
 #ifdef DBUS_BUILD_TESTS
 #include <stdlib.h>
diff --git a/dbus/dbus-sysdeps.h b/dbus/dbus-sysdeps.h
index ecfef69a..8ac131a7 100644
--- a/dbus/dbus-sysdeps.h
+++ b/dbus/dbus-sysdeps.h
@@ -99,6 +99,8 @@ typedef unsigned long dbus_gid_t;
 #define DBUS_UID_FORMAT "%lu"
 #define DBUS_GID_FORMAT "%lu"
 
+#define DBUS_CONSOLE_DIR "/var/run/console/"
+
 /**
  * Struct representing socket credentials
  */
@@ -309,6 +311,9 @@ typedef void (* DBusSignalHandler) (int sig);
 void _dbus_set_signal_handler (int               sig,
                                DBusSignalHandler handler);
 
+dbus_bool_t _dbus_file_exists     (const char *file);
+dbus_bool_t _dbus_user_at_console (const char *username,
+                                   DBusError  *error);
 
 /* Define DBUS_VA_COPY() to do the right thing for copying va_list variables. 
  * config.h may have already defined DBUS_VA_COPY as va_copy or __va_copy. 
diff --git a/dbus/dbus-userdb.c b/dbus/dbus-userdb.c
index 1e105b29..833256c5 100644
--- a/dbus/dbus-userdb.c
+++ b/dbus/dbus-userdb.c
@@ -38,6 +38,7 @@ struct DBusUserDatabase
   DBusHashTable *groups; /**< Groups in the database by GID */
   DBusHashTable *users_by_name; /**< Users in the database by name */
   DBusHashTable *groups_by_name; /**< Groups in the database by name */
+
 };
 
 static void
@@ -399,6 +400,48 @@ _dbus_get_user_id (const DBusString  *username,
 }
 
 /**
+ * Checks to see if the UID sent in is the console user
+ *
+ * @param uid UID of person to check 
+ * @param error return location for errors
+ * @returns #TRUE if the UID is the same as the console user and there are no errors
+ */
+dbus_bool_t
+_dbus_is_console_user (dbus_uid_t uid,
+		       DBusError *error)
+{
+
+  DBusUserDatabase *db;
+  const DBusUserInfo *info;
+  DBusString *console_file;
+  dbus_bool_t result = FALSE; 
+
+  _dbus_user_database_lock_system ();
+
+  db = _dbus_user_database_get_system ();
+  if (db == NULL)
+    {
+      dbus_set_error (error, DBUS_ERROR_FAILED, "Could not get system database.");
+      _dbus_user_database_unlock_system ();
+      return FALSE;
+    }
+
+  info = _dbus_user_database_lookup (db, uid, NULL, error);
+
+  if (info == NULL)
+    {
+      _dbus_user_database_unlock_system ();
+       return FALSE;
+    }
+
+  result = _dbus_user_at_console (info->username, error);
+
+  _dbus_user_database_unlock_system ();
+
+  return result;
+}
+
+/**
  * Gets group ID given groupname
  *
  * @param groupname the groupname
diff --git a/dbus/dbus-userdb.h b/dbus/dbus-userdb.h
index 683b0b76..51f2fa7c 100644
--- a/dbus/dbus-userdb.h
+++ b/dbus/dbus-userdb.h
@@ -56,7 +56,6 @@ dbus_bool_t       _dbus_user_database_get_groupname (DBusUserDatabase     *db,
                                                      DBusError            *error);
 
 
-
 DBusUserDatabase* _dbus_user_database_get_system    (void);
 void              _dbus_user_database_lock_system   (void);
 void              _dbus_user_database_unlock_system (void);
@@ -75,6 +74,8 @@ dbus_bool_t _dbus_credentials_from_username     (const DBusString  *username,
                                                  DBusCredentials   *credentials);
 dbus_bool_t _dbus_credentials_from_uid          (dbus_uid_t         user_id,
                                                  DBusCredentials   *credentials);
+dbus_bool_t _dbus_is_console_user               (dbus_uid_t         uid,
+                                                 DBusError         *error);
 
 
 DBUS_END_DECLS;