Bug 660066 patch 2: Prevent nsFileDataURI from QI'ing to nsSimpleURI. r=bz

content/base/src/nsFileDataProtocolHandler.cpp

@@ -161,12 +161,23 @@ public:
   nsCOMPtr<nsIPrincipal> mPrincipal;
 };
 
+static NS_DEFINE_CID(kThisSimpleURIImplementationCID,
+                     NS_THIS_SIMPLEURI_IMPLEMENTATION_CID);
+
 NS_IMPL_ADDREF_INHERITED(nsFileDataURI, nsSimpleURI)
 NS_IMPL_RELEASE_INHERITED(nsFileDataURI, nsSimpleURI)
+
 NS_INTERFACE_MAP_BEGIN(nsFileDataURI)
   NS_INTERFACE_MAP_ENTRY(nsIURIWithPrincipal)
   if (aIID.Equals(kFILEDATAURICID))
-      foundInterface = static_cast<nsIURI*>(this);
+    foundInterface = static_cast<nsIURI*>(this);
+  else if (aIID.Equals(kThisSimpleURIImplementationCID)) {
+    // Need to return explicitly here, because if we just set foundInterface
+    // to null the NS_INTERFACE_MAP_END_INHERITING will end up calling into
+    // nsSimplURI::QueryInterface and finding something for this CID.
+    *aInstancePtr = nsnull;
+    return NS_NOINTERFACE;
+  }
   else
 NS_INTERFACE_MAP_END_INHERITING(nsSimpleURI)
 

netwerk/test/unit/test_bug660066.js

@@ -0,0 +1,43 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+Components.utils.import("resource://gre/modules/NetUtil.jsm");
+const Ci = Components.interfaces;
+const SIMPLEURI_SPEC = "data:text/plain,hello world";
+const FILEDATA_SPEC = "moz-filedata:123456";
+
+function do_info(text, stack) {
+  if (!stack)
+    stack = Components.stack.caller;
+
+  dump( "\n" +
+       "TEST-INFO | " + stack.filename + " | [" + stack.name + " : " +
+       stack.lineNumber + "] " + text + "\n");
+}
+
+function do_check_uri_neq(uri1, uri2)
+{
+  do_info("Checking equality in forward direction...");
+  do_check_false(uri1.equals(uri2));
+  do_check_false(uri1.equalsExceptRef(uri2));
+
+  do_info("Checking equality in reverse direction...");
+  do_check_false(uri2.equals(uri1));
+  do_check_false(uri2.equalsExceptRef(uri1));
+}
+
+function run_test()
+{
+  var simpleURI = NetUtil.newURI(SIMPLEURI_SPEC);
+  var fileDataURI = NetUtil.newURI(FILEDATA_SPEC);
+
+  do_info("Checking that " + SIMPLEURI_SPEC + " != " + FILEDATA_SPEC);
+  do_check_uri_neq(simpleURI, fileDataURI);
+
+  do_info("Changing the nsSimpleURI spec to match the nsFileDataURI");
+  simpleURI.spec = FILEDATA_SPEC;
+
+  do_info("Verifying that .spec matches");
+  do_check_eq(simpleURI.spec, fileDataURI.spec);
+
+  do_info("Checking that nsSimpleURI != nsFileDataURI despite their .spec matching")
+  do_check_uri_neq(simpleURI, fileDataURI);
+}

netwerk/test/unit/xpcshell.ini

@@ -60,6 +60,7 @@ tail =
 [test_bug652761.js]
 [test_bug651100.js]
 [test_bug659569.js]
+[test_bug660066.js]
 [test_cacheflags.js]
 [test_channel_close.js]
 [test_compareURIs.js]