Replaced StringMethod() with a restrained String method calls

Author: Sim4n6

python/ql/src/experimental/Security/CWE-176/UnicodeBypassValidationQuery.qll

@@ -43,7 +43,35 @@ class Configuration extends TaintTracking::Configuration {
       or
       exists(RegexExecution re | nodeFrom = re.getString() and nodeTo = re)
       or
-      stringManipulation(nodeFrom, nodeTo)
+      // String methods
+      exists(MethodCallNode call, string method_name |
+        nodeTo = call and call.getMethodName() = method_name
+      |
+        call.calls(nodeFrom, method_name) and
+        method_name in [
+            "capitalize", "casefold", "center", "expandtabs", "format", "format_map", "join",
+            "ljust", "lstrip", "lower", "replace", "rjust", "rstrip", "strip", "swapcase", "title",
+            "upper", "zfill", "encode", "decode"
+          ]
+        or
+        method_name = "replace" and
+        nodeFrom = call.getArg(1)
+        or
+        method_name = "format" and
+        nodeFrom = call.getArg(_)
+        or
+        // str -> List[str]
+        call.calls(nodeFrom, method_name) and
+        method_name in ["partition", "rpartition", "rsplit", "split", "splitlines"]
+        or
+        // Iterable[str] -> str
+        method_name = "join" and
+        nodeFrom = call.getArg(0)
+        or
+        // Mapping[str, Any] -> str
+        method_name = "format_map" and
+        nodeFrom = call.getArg(0)
+      )
     ) and
     stateFrom instanceof PreValidation and
     stateTo instanceof PostValidation