bus/driver: Make non-core interfaces unavailable on most object paths

The o.fd.DBus interface needs to remain available on arbitrary object
paths for backwards compatibility, and the Introspectable interface
is genuinely useful, but everything else can be skipped.

This is arguably an incompatible change for the undocumented Verbose
interface, and for the GetAllMatchRules method on the undocumented
Stats interface: previously those were available at all object paths.

Reviewed-by: Philip Withnall <withnall@endlessm.com>
[smcv: Adjust comments, enum order, variable naming as per Philip's review]
Signed-off-by: Simon McVittie <smcv@collabora.com>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=101256

diff --git a/bus/driver.c b/bus/driver.c
index 34b8686..4a68cf2 100644 (file)
--- a/bus/driver.c
+++ b/bus/driver.c
@@ -2200,9 +2200,6 @@ bus_driver_handle_become_monitor (DBusConnection *connection,
 
   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
 
-  if (!bus_driver_check_message_is_for_us (message, error))
-    goto out;
-
   context = bus_transaction_get_context (transaction);
   bustype = context ? bus_context_get_type (context) : NULL;
   if (!bus_apparmor_allows_eavesdropping (connection, bustype, error))
@@ -2418,10 +2415,23 @@ static const MessageHandler stats_message_handlers[] = {
 };
 #endif
 
+typedef enum
+{
+  /* Various older interfaces were available at every object path. We have to
+   * preserve that behaviour for backwards compatibility, but we can at least
+   * stop doing that for newly added interfaces:
+   * <https://bugs.freedesktop.org/show_bug.cgi?id=101256>
+   * Introspectable is also useful at all object paths. */
+  INTERFACE_FLAG_ANY_PATH = (1 << 0),
+
+  INTERFACE_FLAG_NONE = 0
+} InterfaceFlags;
+
 typedef struct {
   const char *name;
   const MessageHandler *message_handlers;
   const char *extra_introspection;
+  InterfaceFlags flags;
 } InterfaceHandler;
 
 /* These should ideally be sorted by frequency of use, although it
@@ -2438,14 +2448,19 @@ static InterfaceHandler interface_handlers[] = {
     "    </signal>\n"
     "    <signal name=\"NameAcquired\">\n"
     "      <arg type=\"s\"/>\n"
-    "    </signal>\n" },
-  { DBUS_INTERFACE_INTROSPECTABLE, introspectable_message_handlers, NULL },
-  { DBUS_INTERFACE_MONITORING, monitoring_message_handlers, NULL },
+    "    </signal>\n",
+    INTERFACE_FLAG_ANY_PATH },
+  { DBUS_INTERFACE_INTROSPECTABLE, introspectable_message_handlers, NULL,
+    INTERFACE_FLAG_ANY_PATH },
+  { DBUS_INTERFACE_MONITORING, monitoring_message_handlers, NULL,
+    INTERFACE_FLAG_NONE },
 #ifdef DBUS_ENABLE_VERBOSE_MODE
-  { DBUS_INTERFACE_VERBOSE, verbose_message_handlers, NULL },
+  { DBUS_INTERFACE_VERBOSE, verbose_message_handlers, NULL,
+    INTERFACE_FLAG_NONE },
 #endif
 #ifdef DBUS_ENABLE_STATS
-  { BUS_INTERFACE_STATS, stats_message_handlers, NULL },
+  { BUS_INTERFACE_STATS, stats_message_handlers, NULL,
+    INTERFACE_FLAG_NONE },
 #endif
   { NULL, NULL, NULL }
 };
@@ -2486,7 +2501,8 @@ write_args_for_direction (DBusString *xml,
 }
 
 dbus_bool_t
-bus_driver_generate_introspect_string (DBusString *xml)
+bus_driver_generate_introspect_string (DBusString *xml,
+                                       dbus_bool_t is_canonical_path)
 {
   const InterfaceHandler *ih;
   const MessageHandler *mh;
@@ -2498,6 +2514,9 @@ bus_driver_generate_introspect_string (DBusString *xml)
 
   for (ih = interface_handlers; ih->name != NULL; ih++)
     {
+      if (!(is_canonical_path || (ih->flags & INTERFACE_FLAG_ANY_PATH)))
+        continue;
+
       if (!_dbus_string_append_printf (xml, "  <interface name=\"%s\">\n",
                                        ih->name))
         return FALSE;
@@ -2541,6 +2560,7 @@ bus_driver_handle_introspect (DBusConnection *connection,
   DBusString xml;
   DBusMessage *reply;
   const char *v_STRING;
+  dbus_bool_t is_canonical_path;
 
   _dbus_verbose ("Introspect() on bus driver\n");
 
@@ -2561,7 +2581,9 @@ bus_driver_handle_introspect (DBusConnection *connection,
       return FALSE;
     }
 
-  if (!bus_driver_generate_introspect_string (&xml))
+  is_canonical_path = dbus_message_has_path (message, DBUS_PATH_DBUS);
+
+  if (!bus_driver_generate_introspect_string (&xml, is_canonical_path))
     goto oom;
 
   v_STRING = _dbus_string_get_const_data (&xml);
@@ -2636,6 +2658,7 @@ bus_driver_handle_message (DBusConnection *connection,
   const InterfaceHandler *ih;
   const MessageHandler *mh;
   dbus_bool_t found_interface = FALSE;
+  dbus_bool_t is_canonical_path;
 
   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
 
@@ -2701,8 +2724,13 @@ bus_driver_handle_message (DBusConnection *connection,
   _dbus_assert (dbus_message_get_sender (message) != NULL ||
                 strcmp (name, "Hello") == 0);
 
+  is_canonical_path = dbus_message_has_path (message, DBUS_PATH_DBUS);
+
   for (ih = interface_handlers; ih->name != NULL; ih++)
     {
+      if (!(is_canonical_path || (ih->flags & INTERFACE_FLAG_ANY_PATH)))
+        continue;
+
       if (interface != NULL && strcmp (interface, ih->name) != 0)
         continue;
 

diff --git a/bus/driver.h b/bus/driver.h
index 201709c..30513ac 100644 (file)
--- a/bus/driver.h
+++ b/bus/driver.h
@@ -45,7 +45,8 @@ dbus_bool_t bus_driver_send_service_owner_changed  (const char     *service_name
                                                    const char     *new_owner,
                                                    BusTransaction *transaction,
                                                    DBusError      *error);
-dbus_bool_t bus_driver_generate_introspect_string  (DBusString *xml);
+dbus_bool_t bus_driver_generate_introspect_string  (DBusString *xml,
+                                                    dbus_bool_t canonical_path);
 dbus_bool_t bus_driver_check_message_is_for_us     (DBusMessage *message,
                                                     DBusError   *error);
 

diff --git a/bus/main.c b/bus/main.c
index 17750ef..7131319 100644 (file)
--- a/bus/main.c
+++ b/bus/main.c
@@ -189,7 +189,7 @@ introspect (void)
   if (!_dbus_string_init (&xml))
     goto oom;
 
-  if (!bus_driver_generate_introspect_string (&xml))
+  if (!bus_driver_generate_introspect_string (&xml, TRUE))
     {
       _dbus_string_free (&xml);
       goto oom;

diff --git a/bus/stats.c b/bus/stats.c
index dace0e2..065a09d 100644 (file)
--- a/bus/stats.c
+++ b/bus/stats.c
@@ -51,9 +51,6 @@ bus_stats_handle_get_stats (DBusConnection *connection,
 
   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
 
-  if (!bus_driver_check_message_is_for_us (message, error))
-    return FALSE;
-
   context = bus_transaction_get_context (transaction);
   connections = bus_context_get_connections (context);
 
@@ -136,9 +133,6 @@ bus_stats_handle_get_connection_stats (DBusConnection *caller_connection,
 
   _DBUS_ASSERT_ERROR_IS_CLEAR (error);
 
-  if (!bus_driver_check_message_is_for_us (message, error))
-    return FALSE;
-
   registry = bus_connection_get_registry (caller_connection);
 
   if (! dbus_message_get_args (message, error,

diff --git a/test/monitor.c b/test/monitor.c
index 71ae2ae..3c43671 100644 (file)
--- a/test/monitor.c
+++ b/test/monitor.c
@@ -642,7 +642,7 @@ test_invalid (Fixture *f,
 
   g_assert_cmpint (dbus_message_get_type (m), ==, DBUS_MESSAGE_TYPE_ERROR);
   g_assert_cmpstr (dbus_message_get_error_name (m), ==,
-      DBUS_ERROR_ACCESS_DENIED);
+      DBUS_ERROR_UNKNOWN_INTERFACE);
 
   /* Try to become a monitor but specify a bad match rule -
    * also not allowed */