Limit Mojo messages recursion depth

mojo/public/cpp/bindings/lib/validation_util.h

Index: mojo/public/cpp/bindings/lib/validation_util.h
diff --git a/mojo/public/cpp/bindings/lib/validation_util.h b/mojo/public/cpp/bindings/lib/validation_util.h
index 59df79f63166a4b93b85af11828196544bd7ac55..521ab5cb46cee55c5763e05234e1bfdf6c36cfb4 100644
--- a/mojo/public/cpp/bindings/lib/validation_util.h
+++ b/mojo/public/cpp/bindings/lib/validation_util.h
@@ -132,6 +132,12 @@ template <typename T>
 bool ValidateContainer(const Pointer<T>& input,
                        ValidationContext* validation_context,
                        const ContainerValidateParams* validate_params) {
+  ValidationContext::ScopedDepthTracker depth_tracker(validation_context);
+  if (validation_context->ExceedsMaxDepth()) {
+    ReportValidationError(validation_context,
+                          VALIDATION_ERROR_MAX_RECURSION_DEPTH);
+    return false;
+  }
   return ValidatePointer(input, validation_context) &&
          T::Validate(input.Get(), validation_context, validate_params);
 }
@@ -139,6 +145,12 @@ bool ValidateContainer(const Pointer<T>& input,
 template <typename T>
 bool ValidateStruct(const Pointer<T>& input,
                     ValidationContext* validation_context) {
+  ValidationContext::ScopedDepthTracker depth_tracker(validation_context);
+  if (validation_context->ExceedsMaxDepth()) {
+    ReportValidationError(validation_context,
+                          VALIDATION_ERROR_MAX_RECURSION_DEPTH);
+    return false;
+  }
   return ValidatePointer(input, validation_context) &&
          T::Validate(input.Get(), validation_context);
 }
@@ -146,12 +158,24 @@ bool ValidateStruct(const Pointer<T>& input,
 template <typename T>
 bool ValidateInlinedUnion(const T& input,
                           ValidationContext* validation_context) {
+  ValidationContext::ScopedDepthTracker depth_tracker(validation_context);
+  if (validation_context->ExceedsMaxDepth()) {
+    ReportValidationError(validation_context,
+                          VALIDATION_ERROR_MAX_RECURSION_DEPTH);
+    return false;
+  }
   return T::Validate(&input, validation_context, true);
 }
 
 template <typename T>
 bool ValidateNonInlinedUnion(const Pointer<T>& input,
                              ValidationContext* validation_context) {
+  ValidationContext::ScopedDepthTracker depth_tracker(validation_context);
+  if (validation_context->ExceedsMaxDepth()) {
+    ReportValidationError(validation_context,
+                          VALIDATION_ERROR_MAX_RECURSION_DEPTH);
+    return false;
+  }
   return ValidatePointer(input, validation_context) &&
          T::Validate(input.Get(), validation_context, false);
 }