Bug 1493222 - Expose InspectorUtils to fuzzers. r=bzbarsky

I can be more granular if we want, by adding more ChromeOnly annotations for the
functions that we don't want to expose.

Differential Revision: https://phabricator.services.mozilla.com/D6530

--HG--
extra : moz-landing-system : lando

dom/base/nsContentUtils.cpp

@@ -2211,6 +2211,14 @@ nsContentUtils::IsCallerChrome()
   return xpc::IsUniversalXPConnectEnabled(GetCurrentJSContext());
 }
 
+#ifdef FUZZING
+bool
+nsContentUtils::IsFuzzingEnabled()
+{
+  return StaticPrefs::fuzzing_enabled();
+}
+#endif
+
 /* static */
 bool
 nsContentUtils::ShouldResistFingerprinting()

dom/base/nsContentUtils.h

@@ -219,6 +219,19 @@ public:
   static bool IsCallerChrome();
   static bool ThreadsafeIsCallerChrome();
   static bool IsCallerContentXBL();
+  static bool IsFuzzingEnabled()
+#ifndef FUZZING
+  {
+    return false;
+  }
+#else
+  ;
+#endif
+
+  static bool IsCallerChromeOrFuzzingEnabled(JSContext* aCx, JSObject*)
+  {
+    return ThreadsafeIsSystemCaller(aCx) || IsFuzzingEnabled();
+  }
 
   // The APIs for checking whether the caller is system (in the sense of system
   // principal) should only be used when the JSContext is known to accurately

dom/bindings/Configuration.py

@@ -105,6 +105,7 @@ class Configuration(DescriptorProvider):
                             (partialIface.location, iface.location))
                 if not (iface.getExtendedAttribute("ChromeOnly") or
                         iface.getExtendedAttribute("Func") == ["IsChromeOrXBL"] or
+                        iface.getExtendedAttribute("Func") == ["nsContentUtils::IsCallerChromeOrFuzzingEnabled"] or
                         not (iface.hasInterfaceObject() or
                              iface.isNavigatorProperty()) or
                         isInWebIDLRoot(iface.filename())):

dom/bindings/parser/WebIDL.py

@@ -1809,7 +1809,7 @@ class IDLNamespace(IDLInterfaceOrNamespace):
                 if not attr.noArguments():
                     raise WebIDLError("[%s] must not have arguments" % identifier,
                                       [attr.location])
-            elif identifier == "Pref":
+            elif identifier == "Pref" or identifier == "Func":
                 # Known extended attributes that take a string value
                 if not attr.hasValue():
                     raise WebIDLError("[%s] must have a value" % identifier,

dom/chrome-webidl/InspectorUtils.webidl

@@ -9,7 +9,7 @@
  *
  * See InspectorUtils.h for documentation on these methods.
  */
-[ChromeOnly]
+[Func="nsContentUtils::IsCallerChromeOrFuzzingEnabled"]
 namespace InspectorUtils {
   // documentOnly tells whether user and UA sheets should get included.
   sequence<StyleSheet> getAllStyleSheets(Document document, optional boolean documentOnly = false);
@@ -129,7 +129,7 @@ dictionary InspectorFontFeature {
   required DOMString languageSystem;
 };
 
-[ChromeOnly]
+[Func="nsContentUtils::IsCallerChromeOrFuzzingEnabled"]
 interface InspectorFontFace {
   // An indication of how we found this font during font-matching.
   // Note that the same physical font may have been found in multiple ways within a range.

js/xpconnect/src/XPCJSContext.cpp

@@ -30,6 +30,7 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/Services.h"
+#include "mozilla/StaticPrefs.h"
 #include "mozilla/dom/ScriptSettings.h"
 
 #include "nsContentUtils.h"
@@ -861,7 +862,7 @@ ReloadPrefsCallback(const char* pref, XPCJSContext* xpccx)
 #endif // JS_GC_ZEAL
 
 #ifdef FUZZING
-    bool fuzzingEnabled = Preferences::GetBool("fuzzing.enabled");
+    bool fuzzingEnabled = StaticPrefs::fuzzing_enabled();
 #endif
 
     JS::ContextOptionsRef(cx).setBaseline(useBaseline)

modules/libpref/init/StaticPrefList.h

@@ -87,6 +87,20 @@ VARCACHE_PREF(
   RelaxedAtomicBool, false
 )
 
+//---------------------------------------------------------------------------
+// Fuzzing prefs. It's important that these can only be checked in fuzzing
+// builds (when FUZZING is defined), otherwise you could enable the fuzzing
+// stuff on your regular build which would be bad :)
+//---------------------------------------------------------------------------
+
+#ifdef FUZZING
+VARCACHE_PREF(
+  "fuzzing.enabled",
+   fuzzing_enabled,
+  bool, false
+)
+#endif
+
 //---------------------------------------------------------------------------
 // Clipboard prefs
 //---------------------------------------------------------------------------

modules/libpref/init/all.js

@@ -5813,10 +5813,6 @@ pref("dom.payments.loglevel", "Warn");
 pref("dom.payments.defaults.saveCreditCard", false);
 pref("dom.payments.defaults.saveAddress", true);
 
-#ifdef FUZZING
-pref("fuzzing.enabled", false);
-#endif
-
 #ifdef MOZ_ASAN_REPORTER
 pref("asanreporter.apiurl", "https://anf1.fuzzing.mozilla.org/crashproxy/submit/");
 pref("asanreporter.clientid", "unknown");