Harden FIFA17 SBC dispatch repair

openfut-hook/src/sbc_dispatch.rs

@@ -92,6 +92,7 @@ enum Rejection {
     ReaderMissing,
     ParseFailed,
     ResponseClassMismatch,
+    ModelChanged,
     ModelEmpty,
     NotifierNotCurrent,
     ControllerMismatch,
@@ -118,6 +119,7 @@ struct DecisionInput {
     deserializer_thread: usize,
     response_class_matches: bool,
     model: usize,
+    live_category_count: usize,
     category_count: usize,
     notifier_entries: u64,
     notifier_exits: u64,
@@ -175,6 +177,9 @@ fn decide(input: DecisionInput) -> Result<Decision, Rejection> {
     if input.model == 0 || input.category_count == 0 || input.category_count == usize::MAX {
         return Err(Rejection::ModelEmpty);
     }
+    if input.live_category_count != input.category_count {
+        return Err(Rejection::ModelChanged);
+    }
     if input.notifier_entries != generation
         || input.notifier_entries == 0
         || input.notifier_exits.checked_add(1) != Some(input.notifier_entries)
@@ -265,6 +270,12 @@ unsafe extern "system" fn completion_wrapper(
 
     let response_vtable = crate::sbc_trace::guarded_usize(evidence.deserializer_this);
     let captured_controller = SBC_CONTROLLER.load(Ordering::Acquire);
+    let live_category_count = evidence
+        .model
+        .checked_add(0x50)
+        .and_then(|address| crate::sbc_trace::guarded_u16(address))
+        .map(usize::from)
+        .unwrap_or(usize::MAX);
     let (controller_matches, controller_model_matches) =
         controller_identity(evidence.base, captured_controller, evidence.model);
     let input = DecisionInput {
@@ -287,6 +298,7 @@ unsafe extern "system" fn completion_wrapper(
         response_class_matches: response_vtable
             == evidence.base.checked_add(CATEGORY_RESPONSE_VTABLE_RVA),
         model: evidence.model,
+        live_category_count,
         category_count: evidence.category_count,
         notifier_entries: evidence.notifier_entries,
         notifier_exits: evidence.notifier_exits,
@@ -676,6 +688,7 @@ mod tests {
             deserializer_thread: 7,
             response_class_matches: true,
             model: 0x4000,
+            live_category_count: 2,
             category_count: 2,
             notifier_entries: generation,
             notifier_exits: generation - 1,
@@ -731,6 +744,10 @@ mod tests {
         let mut input = valid_input(1);
         input.controller_model_matches = false;
         assert_eq!(decide(input), Err(Rejection::ControllerModelMismatch));
+
+        let mut input = valid_input(1);
+        input.live_category_count = 0;
+        assert_eq!(decide(input), Err(Rejection::ModelChanged));
     }
 
     #[test]