Fix #309, avoid catastrophic backtracking in searchcommands.internals

Author: mschwager

splunklib/searchcommands/internals.py

@@ -232,7 +232,7 @@ def replace(match):
 
     _escaped_character_re = re.compile(r'(\\.|""|[\\"])')
 
-    _fieldnames_re = re.compile(r"""("(?:\\.|""|[^"])+"|(?:\\.|[^\s"])+)""")
+    _fieldnames_re = re.compile(r"""("(?:\\.|""|[^"\\])+"|(?:\\.|[^\s"])+)""")
 
     _options_re = re.compile(r"""
         # Captures a set of name/value pairs when used with re.finditer