diff --git a/gatekeeperd/gatekeeperd.cpp b/gatekeeperd/gatekeeperd.cpp
index 6622df9..cd6d18f 100644
--- a/gatekeeperd/gatekeeperd.cpp
+++ b/gatekeeperd/gatekeeperd.cpp
@@ -112,6 +112,7 @@
         int fd = open(filename, O_RDONLY);
         if (fd < 0) return 0;
         read(fd, &sid, sizeof(sid));
+        close(fd);
         return sid;
     }