Don't compile functions in a context the caller doesn't have access to

src/runtime/runtime-compiler.cc

Index: src/runtime/runtime-compiler.cc
diff --git a/src/runtime/runtime-compiler.cc b/src/runtime/runtime-compiler.cc
index 8790da05e39a1b62b50da1d22a1c229d02c79684..d115c35e22847276d17ea5bcc0e2c6eef015ffb1 100644
--- a/src/runtime/runtime-compiler.cc
+++ b/src/runtime/runtime-compiler.cc
@@ -352,6 +352,59 @@ bool CodeGenerationFromStringsAllowed(Isolate* isolate,
 }
 
 
+// Walk up the stack expecting:
+//  - Runtime_CompileString
+//  - JSFunction callee (eval, Function constructor, etc)
+//  - call() (maybe)
+//  - apply() (maybe)
+//  - bind() (maybe)
+// - JSFunction caller (maybe)
+//
+// return true if the caller has access to the callee or if an exit frame was
+// hit, in which case allow it through, as it could have come through the api.
+bool HasAccessToContextForCompileString(Isolate* isolate) {
+  MaybeHandle<JSFunction> callee;
+  bool exit_handled = true;
+  bool has_access = true;
+  bool done = false;
+  for (StackFrameIterator it(isolate); !it.done() && !done; it.Advance()) {
+    StackFrame* raw_frame = it.frame();
+    if (!raw_frame->is_java_script()) {
+      if (raw_frame->is_exit()) exit_handled = false;
+      continue;
+    }
+    JavaScriptFrame* outer_frame = JavaScriptFrame::cast(raw_frame);
+    List<FrameSummary> frames(FLAG_max_inlining_levels + 1);
+    outer_frame->Summarize(&frames);
+    for (int i = frames.length() - 1; i >= 0 && !done; --i) {
+      FrameSummary& frame = frames[i];
+      Handle<JSFunction> fun = frame.function();
+      // Capture the callee function.
+      if (callee.is_null()) {
+        callee = fun;
+        exit_handled = true;
+        continue;
+      }
+      // Exit condition.
+      Handle<JSObject> callee_global_proxy(
+          callee.ToHandleChecked()->context()->global_proxy());
+      if (!isolate->MayAccess(handle(fun->context()), callee_global_proxy)) {
+        has_access = false;
+        done = true;
+        continue;
+      }
+      // Skip bound functions in correct origin.
+      if (fun->shared()->bound()) {
+        exit_handled = true;
+        continue;
+      }
+      done = true;
+    }
+  }
+  return !exit_handled || has_access;
+}
+
+
 RUNTIME_FUNCTION(Runtime_CompileString) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
@@ -361,6 +414,11 @@ RUNTIME_FUNCTION(Runtime_CompileString) {
   // Extract native context.
   Handle<Context> context(isolate->native_context());
 
+  // Filter cross security context calls.
+  if (!HasAccessToContextForCompileString(isolate)) {
+    return isolate->heap()->undefined_value();
+  }
+
   // Check if native context allows code generation from
   // strings. Throw an exception if it doesn't.
   if (context->allow_code_gen_from_strings()->IsFalse() &&