Mitigate the pushState IPC storm DoS.

third_party/WebKit/Source/core/frame/History.cpp

Index: third_party/WebKit/Source/core/frame/History.cpp
diff --git a/third_party/WebKit/Source/core/frame/History.cpp b/third_party/WebKit/Source/core/frame/History.cpp
index 30ebcc037c8ef77fc46f2cb63e954175ea56360a..b8a0738fe1f279a6cc008e01a154dc7ec8683179 100644
--- a/third_party/WebKit/Source/core/frame/History.cpp
+++ b/third_party/WebKit/Source/core/frame/History.cpp
@@ -116,6 +116,28 @@ HistoryScrollRestorationType History::ScrollRestorationInternal() const {
                       : kScrollRestorationAuto;
 }
 
+// TODO(crbug.com/394296): This is not the long-term fix to IPC flooding that we
+// need. However, it does somewhat mitigate the immediate concern of |pushState|
+// and |replaceState| DoS (assuming the renderer has not been compromised).
+bool History::ShouldThrottleStateObjectChanges() {
+  const int kStateUpdateLimit = 50;
+
+  if (state_flood_guard.count > kStateUpdateLimit) {
+    static constexpr auto kStateUpdateLimitResetInterval =
+        TimeDelta::FromSeconds(10);
+    const auto now = TimeTicks::Now();
+    if (now - state_flood_guard.last_updated > kStateUpdateLimitResetInterval) {
+      state_flood_guard.count = 0;
+      state_flood_guard.last_updated = now;
+      return false;
+    }
+    return true;
+  }
+
+  state_flood_guard.count++;
+  return false;
+}
+
 bool History::stateChanged() const {
   return last_state_object_requested_ != StateInternal();
 }
@@ -216,6 +238,10 @@ void History::StateObjectAdded(PassRefPtr<SerializedScriptValue> data,
       !GetFrame()->Loader().GetDocumentLoader())
     return;
 
+  if (ShouldThrottleStateObjectChanges()) {
+    return;
+  }

[kinuko, 2017/07/10 05:10:49]

nit: no { } needed

Do we want to have this after the CanChangeToUrl check below?

[palmer, 2017/07/10 19:42:25]

Done.
Done.

+
   KURL full_url = UrlForState(url_string);
   if (!CanChangeToUrl(full_url, GetFrame()->GetDocument()->GetSecurityOrigin(),
                       GetFrame()->GetDocument()->Url())) {