AP_RCProtocol: fixed underflow wrap in GHST

ArduPilot · Apr 6, 2024 · 37fb9b3 · 37fb9b3
1 parent b0042c1
commit 37fb9b3
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/libraries/AP_RCProtocol/AP_RCProtocol_GHST.cpp b/libraries/AP_RCProtocol/AP_RCProtocol_GHST.cpp
@@ -177,6 +177,12 @@ void AP_RCProtocol_GHST::_process_byte(uint32_t timestamp_us, uint8_t byte)
         return;
     }
 
+    if (_frame.length < 2) {
+        // invalid length, we subtract 2 below
+        _frame_ofs = 0;
+        return;
+    }
+
     // decode whatever we got and expect
     if (_frame_ofs == _frame.length + GHST_HEADER_LEN) {
         log_data(AP_RCProtocol::GHST, timestamp_us, (const uint8_t*)&_frame, _frame_ofs - GHST_HEADER_LEN);