C++: Stop taint from flowing to arithmetic types

These are not likely to give the user much control over what can be accessed.

cpp/ql/src/Security/CWE/CWE-022/TaintedPath.ql

@@ -75,6 +75,10 @@ class TaintedPathConfiguration extends TaintTracking::Configuration {
   }
 
   override predicate isSanitizerIn(DataFlow::Node node) { this.isSource(node) }
+
+  override predicate isSanitizer(DataFlow::Node node) {
+    node.asExpr().(Call).getTarget().getUnspecifiedType() instanceof ArithmeticType
+  }
 }
 
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