diff -r 000000000000 -r 6474c204b198 modules/libjar/test/unit/test_bug658093.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/libjar/test/unit/test_bug658093.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,23 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+
+// Check that we don't crash on reading a directory entry signature
+var ios = Cc["@mozilla.org/network/io-service;1"].
+          getService(Ci.nsIIOService);
+
+function run_test() {
+  var file = do_get_file("data/test_bug658093.zip");
+  var spec = "jar:" + ios.newFileURI(file).spec + "!/0000";
+  var channel = ios.newChannel(spec, null, null);
+  var failed = false;
+  try {
+    var stream = channel.open();
+  } catch (e) {
+    failed = true;
+  }
+  do_check_true(failed);
+}