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from time import strftime, localtime |
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from spike.model import db |
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from shlex import shlex |
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class NaxsiRules(db.Model): |
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__bind_key__ = 'rules' |
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__tablename__ = 'naxsi_rules' |
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id = db.Column(db.Integer, primary_key=True) |
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msg = db.Column(db.String(), nullable=False) |
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detection = db.Column(db.String(1024), nullable=False) |
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mz = db.Column(db.String(1024), nullable=False) |
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score = db.Column(db.String(1024), nullable=False) |
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sid = db.Column(db.Integer, nullable=False, unique=True) |
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ruleset = db.Column(db.String(1024), nullable=False) |
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rmks = db.Column(db.Text, nullable=True, server_default="") |
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active = db.Column(db.Integer, nullable=False, server_default="1") |
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negative = db.Column(db.Integer, nullable=False, server_default='0') |
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timestamp = db.Column(db.Integer, nullable=False) |
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mr_kw = ["MainRule", "BasicRule", "main_rule", "basic_rule"] |
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static_mz = {"$ARGS_VAR", "$BODY_VAR", "$URL", "$HEADERS_VAR"} |
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full_zones = {"ARGS", "BODY", "URL", "HEADERS", "FILE_EXT", "RAW_BODY"} |
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rx_mz = {"$ARGS_VAR_X", "$BODY_VAR_X", "$URL_X", "$HEADERS_VAR_X"} |
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sub_mz = list(static_mz) + list(full_zones) + list(rx_mz) |
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def __init__(self, msg="", detection="str:a", mz="ARGS", score="$None:0", sid='42000', ruleset="", rmks="", |
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active=0, negative=False, timestamp=0): |
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self.msg = msg |
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self.detection = detection |
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self.mz = mz |
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self.score = score |
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self.sid = sid |
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self.ruleset = ruleset |
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self.rmks = rmks |
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self.active = active |
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self.negative = negative |
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self.timestamp = timestamp |
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self.warnings = [] |
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self.error = [] |
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def fullstr(self): |
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rdate = strftime("%F - %H:%M", localtime(float(str(self.timestamp)))) |
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rmks = "# ".join(self.rmks.strip().split("\n")) |
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return "#\n# sid: {0} | date: {1}\n#\n# {2}\n#\n{3}".format(self.sid, rdate, rmks, self.__str__()) |
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def __str__(self): |
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return 'MainRule {} "{}" "msg:{}" "mz:{}" "s:{}" id:{} ;'.format( |
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'negative' if self.negative else '', self.detection, self.msg, self.mz, self.score, self.sid) |
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def explain(self): |
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""" Return a string explaining the rule |
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:return str: A textual explanation of the rule |
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""" |
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translation = {'ARGS': 'argument', 'BODY': 'body', 'URL': 'url', 'HEADER': 'header', |
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'HEADER:Cookie': 'cookies'} |
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explanation = 'The rule number <strong>{0}</strong> is '.format(self.sid) |
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if self.negative: |
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explanation += '<strong>not</strong> ' |
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explanation += 'setting the ' |
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scores = [] |
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for score in self.score.split(','): |
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scores.append('<strong>{0}</strong> score to <strong>{1}</strong> '.format(*score.split(':', 1))) |
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explanation += ', '.join(scores) + 'when it ' |
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if self.detection.startswith('str:'): |
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explanation += 'finds the string <strong>{}</strong> '.format(self.detection[4:]) |
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else: |
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explanation += 'matches the regexp <strong>{}</strong> in '.format(self.detection[3:]) |
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zones = [] |
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for mz in self.mz.split('|'): |
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if mz.startswith('$'): |
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current_zone, arg = mz.split(":", 1) |
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zone_name = "?" |
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for translated_name in translation: # translate zone names |
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if translated_name in current_zone: |
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zone_name = translation[translated_name] |
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if "$URL" in current_zone: |
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regexp = "matching regex" if current_zone == "$URL_X" else "" |
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zones.append("on the URL {} '{}' ".format(regexp, arg)) |
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else: |
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regexp = "matching regex" if current_zone.endswith("_X") else "" |
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if zone_name == 'header' and arg.lower() == 'cookie': |
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zones.append('in the <strong>cookies</strong>') |
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else: |
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zones.append("in the var with name {} '{}' of {} ".format(regexp, arg, zone_name)) |
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else: |
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zones.append('the <strong>{0}</strong>'.format(translation[mz])) |
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return explanation + ' ' + ', '.join(zones) + '.' |
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def validate(self): |
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self.warnings = list() |
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self.error = list() |
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self.__validate_matchzone(self.mz) |
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self.__validate_id(self.sid) |
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self.__validate_score(self.score) |
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if self.detection.startswith('rx:'): |
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self.__validate_detection_rx(self.detection) |
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elif self.detection.startswith('str:'): |
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self.__validate_detection_str(self.detection) |
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else: |
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self.error.append("Your 'detection' string must start with str: or rx:") |
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if not self.msg: |
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self.warnings.append("Rule has no 'msg:'.") |
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if not self.score: |
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self.error.append("Rule has no score.") |
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elif not self.mz: |
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self.error.append("Rule has no match zone.") |
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elif not self.sid: |
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self.error.append("Rule has no sid.") |
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def __fail(self, msg): |
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self.error.append(msg) |
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return False |
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# Bellow are parsers for specific parts of a rule |
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def __validate_detection_str(self, p_str, assign=False): |
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if assign is True: |
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self.detection = p_str |
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return True |
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def __validate_detection_rx(self, p_str, assign=False): |
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if not p_str.islower(): |
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self.warnings.append("detection {} is not lower-case. naxsi is case-insensitive".format(p_str)) |
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try: # try to validate the regex with PCRE's python bindings |
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import pcre |
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try: # if we can't compile the regex, it's likely invalid |
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pcre.compile(p_str[3:]) |
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except pcre.PCREError: |
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return self.__fail("{} is not a valid regex:".format(p_str)) |
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except ImportError: # python-pcre is an optional dependency |
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pass |
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if assign is True: |
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self.detection = p_str |
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return True |
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def __validate_score(self, p_str, assign=False): |
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for score in p_str.split(','): |
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if ':' not in score: |
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self.__fail("You score '{}' has no value or name.".format(score)) |
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name, value = score.split(':') |
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if not value.isdigit(): |
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self.__fail("Your value '{}' for your score '{}' is not numeric.".format(value, score)) |
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elif not name.startswith('$'): |
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self.__fail("Your name '{}' for your score '{}' does not start with a '$'.".format(name, score)) |
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if assign: |
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self.score = p_str |
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return True |
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def __validate_matchzone(self, p_str, assign=False): |
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has_zone = False |
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mz_state = set() |
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for loc in p_str.split('|'): |
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keyword, arg = loc, None |
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if loc.startswith("$"): |
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if loc.find(":") == -1: |
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return self.__fail("Missing 2nd part after ':' in {0}".format(loc)) |
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keyword, arg = loc.split(":") |
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if keyword not in self.sub_mz: # check if `keyword` is a valid keyword |
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return self.__fail("'{0}' is not a known sub-part of mz : {1}".format(keyword, self.sub_mz)) |
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mz_state.add(keyword) |
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# verify that the rule doesn't attempt to target REGEX and STATIC _VAR/URL at the same time |
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if len(self.rx_mz & mz_state) and len(self.static_mz & mz_state): |
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return self.__fail("You can't mix static $* with regex $*_X ({})".format(', '.join(mz_state))) |
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if arg and not arg.islower(): # just a gentle reminder |
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self.warnings.append("{0} in {1} is not lowercase. naxsi is case-insensitive".format(arg, loc)) |
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# the rule targets an actual zone |
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if keyword not in ["$URL", "$URL_X"] and keyword in (self.rx_mz | self.full_zones | self.static_mz): |
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has_zone = True |
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if has_zone is False: |
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return self.__fail("The rule/whitelist doesn't target any zone.") |
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if assign is True: |
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self.mz = p_str |
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return True |
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def __validate_id(self, p_str, assign=False): |
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try: |
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num = int(p_str) |
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if num < 10000: |
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self.warnings.append("rule IDs below 10k are reserved ({0})".format(num)) |
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except ValueError: |
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self.error.append("id:{0} is not numeric".format(p_str)) |
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return False |
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if assign is True: |
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self.sid = num |
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return True |
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@staticmethod |
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def __splitter(full_str): |
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lexer = shlex(full_str) |
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lexer.whitespace_split = True |
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return list(iter(lexer.get_token, '')) |
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def parse_rule(self, full_str): |
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""" |
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Parse and validate a full naxsi rule |
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:param full_str: raw rule |
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:return: [True|False, dict] |
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""" |
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self.warnings = list() |
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self.error = list() |
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func_map = {"id:": self.__validate_id, "str:": self.__validate_detection_str, |
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"rx:": self.__validate_detection_rx, "msg:": lambda p_str, assign=False: True, |
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"mz:": self.__validate_matchzone, "negative": lambda p_str, assign=False: p_str == 'checked', |
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"s:": self.__validate_score} |
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split = self.__splitter(full_str) # parse string |
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intersection = set(split).intersection(set(self.mr_kw)) |
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if not intersection: |
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return self.__fail("No mainrule/basicrule keyword.") |
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elif len(intersection) > 1: |
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return self.__fail("Multiple mainrule/basicrule keywords.") |
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split.remove(intersection.pop()) # remove the mainrule/basicrule keyword |
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if ";" in split: |
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split.remove(";") |
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for keyword in split: |
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keyword = keyword.strip() |
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if keyword.endswith(";"): # remove semi-colons |
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keyword = keyword[:-1] |
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if keyword.startswith(('"', "'")) and (keyword[0] == keyword[-1]): # remove (double-)quotes |
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keyword = keyword[1:-1] |
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parsed = False |
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for frag_kw in func_map: |
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if keyword.startswith(frag_kw): # use the right parser |
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if frag_kw in ('rx:', 'str:'): # don't remove the leading "str:" or "rx:" |
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payload = keyword |
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else: |
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payload = keyword[len(frag_kw):] |
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function = func_map[frag_kw] # we're using an array of functions, C style! |
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if function(payload, assign=True) is True: |
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parsed = True |
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break |
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return self.__fail("parsing of element '{0}' failed.".format(keyword)) |
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if parsed is False: # we have an item that wasn't successfully parsed |
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return self.__fail("'{}' is an invalid element and thus can not be parsed.".format(keyword)) |
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return True |
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Except handlers which only contain
pass
and do not have anelse
clause can usually simply be removed: