From b2747b076e845d5041783e5ded000d657ea8c4da Mon Sep 17 00:00:00 2001
From: Stephen Chung <Stephen.Chung@intexact.com>
Date: Sun, 23 Feb 2020 14:09:40 +0800
Subject: [PATCH] Add bouncs check to array index access.

---
 src/engine.rs | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/engine.rs b/src/engine.rs
index 3e9a3278..6a1543af 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -513,8 +513,14 @@ impl Engine {
                                     if let Some(arr_typed) =
                                         (*val).downcast_mut() as Option<&mut Vec<Box<dyn Any>>>
                                     {
-                                        arr_typed[i as usize] = rhs_val;
-                                        return Ok(Box::new(()));
+                                        return if i < 0 {
+                                            Err(EvalAltResult::ErrorArrayOutOfBounds(0, i))
+                                        } else if i as usize >= arr_typed.len() {
+                                            Err(EvalAltResult::ErrorArrayOutOfBounds(arr_typed.len(), i))
+                                        } else {
+                                            arr_typed[i as usize] = rhs_val;
+                                            Ok(Box::new(()))
+                                        };
                                     } else {
                                         return Err(EvalAltResult::ErrorIndexMismatch);
                                     }