From da32016d7637095effe3ddaa5e5e4792a2344dae Mon Sep 17 00:00:00 2001
From: Chung-Sheng Fu <cfu@mozilla.com>
Date: Mon, 7 Aug 2017 15:55:39 +0800
Subject: [PATCH] Bug 863246 - Use system principal to load debugger scripts
 r=billm,bkelly

MozReview-Commit-ID: DPvbR1As2UV

--HG--
extra : rebase_source : c185be0d4d2180dd3dd7d0fbcfdd1035f3b4ddf3
---
 dom/workers/ScriptLoader.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/dom/workers/ScriptLoader.cpp b/dom/workers/ScriptLoader.cpp
index 0948e8b1f860..461c7f4cd925 100644
--- a/dom/workers/ScriptLoader.cpp
+++ b/dom/workers/ScriptLoader.cpp
@@ -894,10 +894,19 @@ private:
   {
     AssertIsOnMainThread();
     MOZ_ASSERT(aIndex < mLoadInfos.Length());
+    MOZ_ASSERT_IF(IsMainWorkerScript(), mWorkerScriptType != DebuggerScript);
 
     WorkerPrivate* parentWorker = mWorkerPrivate->GetParent();
 
-    nsIPrincipal* principal = mWorkerPrivate->GetPrincipal();
+    // For JavaScript debugging, the devtools server must run on the same
+    // thread as the debuggee, indicating the worker uses content principal.
+    // However, in Bug 863246, web content will no longer be able to load
+    // resource:// URIs by default, so we need system principal to load
+    // debugger scripts.
+    nsIPrincipal* principal = (mWorkerScriptType == DebuggerScript) ?
+                              nsContentUtils::GetSystemPrincipal() :
+                              mWorkerPrivate->GetPrincipal();
+
     nsCOMPtr<nsILoadGroup> loadGroup = mWorkerPrivate->GetLoadGroup();
     MOZ_DIAGNOSTIC_ASSERT(principal);