Swift: Copy query from Ruby.

Author: geoffw0

swift/ql/src/queries/Security/CWE-1333/ReDoS.ql

@@ -0,0 +1,24 @@
+/**
+ * @name Inefficient regular expression
+ * @description A regular expression that requires exponential time to match certain inputs
+ *              can be a performance bottleneck, and may be vulnerable to denial-of-service
+ *              attacks.
+ * @kind problem
+ * @problem.severity error
+ * @security-severity 7.5
+ * @precision high
+ * @id rb/redos
+ * @tags security
+ *       external/cwe/cwe-1333
+ *       external/cwe/cwe-730
+ *       external/cwe/cwe-400
+ */
+
+private import codeql.ruby.regexp.RegExpTreeView::RegexTreeView as TreeView
+import codeql.regex.nfa.ExponentialBackTracking::Make<TreeView>
+
+from TreeView::RegExpTerm t, string pump, State s, string prefixMsg
+where hasReDoSResult(t, pump, s, prefixMsg)
+select t,
+  "This part of the regular expression may cause exponential backtracking on strings " + prefixMsg +
+    "containing many repetitions of '" + pump + "'."