From 9aa166e4debd8e639e39cb366320dce686fd8fa7 Mon Sep 17 00:00:00 2001
From: FellippeHeitor <fellippeheitor@gmail.com>
Date: Thu, 19 Aug 2021 19:10:51 -0300
Subject: [PATCH] Checks for array's lbound and ubound before fetching data.

---
 internal/c/qbx.cpp                |  8 ++++++++
 internal/support/vwatch/vwatch.bm | 15 ++++++++++++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/internal/c/qbx.cpp b/internal/c/qbx.cpp
index 055b79d88..fba71478f 100755
--- a/internal/c/qbx.cpp
+++ b/internal/c/qbx.cpp
@@ -941,6 +941,14 @@ inline int16 func_abs(int16 d){return abs(d);}
 inline int32 func_abs(int32 d){return abs(d);}
 inline int64 func_abs(int64 d){return llabs(d);}
 
+ptrszint check_lbound(ptrszint *array) {
+    return func_lbound((ptrszint*)(*array),1,1);
+}
+
+ptrszint check_ubound(ptrszint *array) {
+    return func_ubound((ptrszint*)(*array),1,1);
+}
+
 inline ptrszint array_check(uptrszint index,uptrszint limit){
     //nb. forces signed index into an unsigned variable for quicker comparison
     if (index<limit) return index;
diff --git a/internal/support/vwatch/vwatch.bm b/internal/support/vwatch/vwatch.bm
index 4b895e357..26c7f1a00 100644
--- a/internal/support/vwatch/vwatch.bm
+++ b/internal/support/vwatch/vwatch.bm
@@ -7,7 +7,7 @@ SUB vwatch (globalVariables AS _OFFSET, localVariables AS _OFFSET)
     STATIC AS _OFFSET vw_idehwnd
     STATIC vw_buffer$
     DIM AS LONG vw_i, vw_tempIndex, vw_localIndex, vw_varSize, vw_cmdsize
-    DIM AS _OFFSET vw_address
+    DIM AS _OFFSET vw_address, vw_lbound, vw_ubound
     DIM AS _MEM vw_m, vw_m2
     DIM AS _BYTE vw_isarray
     DIM vw_start!, vw_temp$, vw_cmd$, vw_value$, vw_k&, vw_buf$, vw_scope$, vw_varType$
@@ -19,6 +19,8 @@ SUB vwatch (globalVariables AS _OFFSET, localVariables AS _OFFSET)
         SUB unlockvWatchHandle
         SUB set_qbs_size (target AS _OFFSET, BYVAL length&)
         FUNCTION stop_program_state&
+        FUNCTION check_lbound%&(array AS _OFFSET)
+        FUNCTION check_ubound%&(array AS _OFFSET)
     END DECLARE
 
     $IF WIN THEN
@@ -280,7 +282,14 @@ SUB vwatch (globalVariables AS _OFFSET, localVariables AS _OFFSET)
                 vw_address = _MEMGET(vw_m, vw_address, _OFFSET) 'second resolve pass
 
                 IF vw_isarray THEN
-                    'get the address of where this array is stored
+                    vw_lbound = check_lbound%&(vw_address)
+                    vw_ubound = check_ubound%&(vw_address)
+
+                    IF vw_arrayIndex < vw_lbound OR vw_arrayIndex > vw_ubound THEN
+                        GOTO cmdProcessingDone
+                    END IF
+
+                    'get the address of where this array's data is stored
                     vw_buf$ = SPACE$(LEN(vw_dummy%&))
                     vw_m = _MEM(vw_address, LEN(vw_dummy%&))
                     vw_m2 = _MEM(_OFFSET(vw_buf$), LEN(vw_dummy%&))
@@ -301,7 +310,7 @@ SUB vwatch (globalVariables AS _OFFSET, localVariables AS _OFFSET)
                     END IF
 
                     'this is where we calculate the actual element position in memory
-                    vw_address = vw_address + ((vw_arrayIndex - 1) * vw_varSize)
+                    vw_address = vw_address + ((vw_arrayIndex - vw_lbound) * vw_varSize)
                 END IF
 
                 'vw_address now points to the actual data