Log to syslog when pending_fd_timeout is exceeded

This is either a denial-of-service attempt, a pathological performance
problem or a dbus-daemon bug. Sysadmins should be told about any of
these.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=86442
[smcv: add units to timeout: it is in milliseconds]
Signed-off-by: Simon McVittie <smcv@debian.org>

diff --git a/bus/connection.c b/bus/connection.c
index 8f5623e..17995ca 100644 (file)
--- a/bus/connection.c
+++ b/bus/connection.c
@@ -671,6 +671,18 @@ static dbus_bool_t
 pending_unix_fds_timeout_cb (void *data)
 {
   DBusConnection *connection = data;
+  BusConnectionData *d = BUS_CONNECTION_DATA (connection);
+  int limit;
+
+  _dbus_assert (d != NULL);
+  limit = bus_context_get_pending_fd_timeout (d->connections->context);
+  bus_context_log (d->connections->context, DBUS_SYSTEM_LOG_WARNING,
+      "Connection \"%s\" (%s) has had Unix fds pending for too long, "
+      "closing it (pending_fd_timeout=%d ms)",
+      d->name != NULL ? d->name : "(null)",
+      bus_connection_get_loginfo (connection),
+      limit);
+
   dbus_connection_close (connection);
   return TRUE;
 }