Detect potentionally unsafe regex patterns

src/util/SafeRe.py

@@ -0,0 +1,20 @@
+import re
+
+
+class UnsafePatternError(Exception):
+    pass
+
+
+def isSafePattern(pattern):
+    if len(pattern) > 255:
+        raise UnsafePatternError("Pattern too long: %s characters" % len(pattern))
+
+    unsafe_pattern_match = re.search("[^\.][\*\{\+]", pattern)  # Always should be "." before "*{+" characters to avoid ReDoS
+    if unsafe_pattern_match:
+        raise UnsafePatternError("Potentially unsafe part of the pattern: %s" % unsafe_pattern_match.group(0))
+    return True
+
+
+def match(pattern, *args, **kwargs):
+    if isSafePattern(pattern):
+        return re.match(pattern, *args, **kwargs)