introducing regex caching mechanism

stamparm · stamparm · commit 5d5ebd49b617 · 2010-05-21T14:42:59.000Z
diff --git a/lib/core/common.py b/lib/core/common.py
@@ -70,6 +70,8 @@
 from lib.core.settings import ACCESS_ALIASES
 from lib.core.settings import FIREBIRD_ALIASES
 
+__compiledRegularExpressions = {}
+
 def paramToDict(place, parameters=None):
     """
     Split the parameters into names and values, check if these parameters
@@ -1222,3 +1224,11 @@ def getGoodSamaritanCharsets(part, prevValue, originalCharset):
         return predictedCharset, otherCharset
     else:
         return None, originalTable
+
+def getCompiledRegex(regex):
+    if regex in __compiledRegularExpressions:
+        return __compiledRegularExpressions[regex]
+    else:
+        retVal = re.compile(regex)
+        __compiledRegularExpressions[regex] = retVal
+        return retVal
diff --git a/lib/parse/banner.py b/lib/parse/banner.py
@@ -27,6 +27,7 @@
 from xml.sax.handler import ContentHandler
 
 from lib.core.common import checkFile
+from lib.core.common import getCompiledRegex
 from lib.core.common import parseXmlFile
 from lib.core.common import sanitizeStr
 from lib.core.data import kb
@@ -76,7 +77,8 @@ def characters(self, data):
     def endElement(self, name):
         if name == "signature":
             for version in (self.__version, self.__versionAlt):
-                if version and re.search(" %s[\.\ ]+" % version, self.__banner):
+                regObj = getCompiledRegex(" %s[\.\ ]+" % version)
+                if version and regObj.search(self.__banner):
                     self.__feedInfo("dbmsRelease", self.__release)
                     self.__feedInfo("dbmsVersion", self.__version)
                     self.__feedInfo("dbmsServicePack", self.__servicePack)
@@ -89,8 +91,9 @@ def endElement(self, name):
         elif name == "version":
             self.__inVersion = False
             self.__version = self.__version.replace(" ", "")
-            
-            match = re.search(r"\A(?P<major>\d+)\.00\.(?P<build>\d+)\Z", self.__version)
+
+            regObj = getCompiledRegex(r"\A(?P<major>\d+)\.00\.(?P<build>\d+)\Z")
+            match = regObj.search(self.__version)
             self.__versionAlt = "%s.0.%s.0" % (match.group('major'), match.group('build')) if match else None
 
         elif name == "servicepack":
diff --git a/lib/request/basic.py b/lib/request/basic.py
@@ -28,6 +28,7 @@
 import StringIO
 import zlib
 
+from lib.core.common import getCompiledRegex
 from lib.core.common import isWindowsDriveLetterPath
 from lib.core.common import posixToNtSlashes
 from lib.core.common import urlEncodeCookieValues
@@ -36,9 +37,6 @@
 from lib.parse.headers import headersParser
 from lib.parse.html import htmlParser
 
-__absFilePathsRegExp = ( r" in <b>(?P<result>.*?)</b> on line",  r"(?:>|\s)(?P<result>[A-Za-z]:[\\/][\w.\\/]*)", r"(?:>|\s)(?P<result>/\w[/\w.]+)" )
-__absFilePathsRegObj = [re.compile(absFilePathRegExp) for absFilePathRegExp in __absFilePathsRegExp]
-
 def forgeHeaders(cookie, ua):
     """
     Prepare HTTP Cookie and HTTP User-Agent headers to use when performing
@@ -78,8 +76,9 @@ def parseResponse(page, headers):
         # NOTE: this regular expression works if the remote web application
         # is written in PHP and debug/error messages are enabled.
 
-        for reobj in __absFilePathsRegObj:
-            for match in reobj.finditer(page):
+        for regex in ( r" in <b>(?P<result>.*?)</b> on line",  r"(?:>|\s)(?P<result>[A-Za-z]:[\\/][\w.\\/]*)", r"(?:>|\s)(?P<result>/\w[/\w.]+)" ):
+            regObj = getCompiledRegex(regex)
+            for match in regObj.finditer(page):
                 absFilePath = match.group("result").strip()
                 page = page.replace(absFilePath, "")
 
diff --git a/lib/utils/detection.py b/lib/utils/detection.py
@@ -24,6 +24,7 @@
 import re, sre_constants
 from xml.dom import minidom
 
+from lib.core.common import getCompiledRegex
 from lib.core.data import paths
 from lib.core.data import logger
 
@@ -50,12 +51,13 @@ def checkPayload(string):
         rules = []
         for xmlrule in xmlrules.getElementsByTagName("filter"):
             try:
-                rule = re.compile(xmlrule.getElementsByTagName('rule')[0].childNodes[0].nodeValue)
+                rule = xmlrule.getElementsByTagName('rule')[0].childNodes[0].nodeValue
                 desc = __adjustGrammar(xmlrule.getElementsByTagName('description')[0].childNodes[0].nodeValue)
                 rules.append((rule, desc))
             except sre_constants.error: #some issues with some regex expressions in Python 2.5
                 pass
     
     for rule, desc in rules:
-        if rule.search(string, re.IGNORECASE):
+        regObj = getCompiledRegex(rule)
+        if regObj.search(string, re.IGNORECASE):
             logger.warn("highly probable IDS/IPS detection: '%s'" % desc)
