Edit File: policy.py
############################################################################ # Copyright (C) Internet Systems Consortium, Inc. ("ISC") # # This Source Code Form is subject to the terms of the Mozilla Public # License, v. 2.0. If a copy of the MPL was not distributed with this # file, You can obtain one at http://mozilla.org/MPL/2.0/. # # See the COPYRIGHT file distributed with this work for additional # information regarding copyright ownership. ############################################################################ import re import ply.lex as lex import ply.yacc as yacc from string import * from copy import copy ############################################################################ # PolicyLex: a lexer for the policy file syntax. ############################################################################ class PolicyLex: reserved = ('POLICY', 'ALGORITHM_POLICY', 'ZONE', 'ALGORITHM', 'DIRECTORY', 'KEYTTL', 'KEY_SIZE', 'ROLL_PERIOD', 'PRE_PUBLISH', 'POST_PUBLISH', 'COVERAGE', 'STANDBY', 'NONE') tokens = reserved + ('DATESUFFIX', 'KEYTYPE', 'ALGNAME', 'STR', 'QSTRING', 'NUMBER', 'LBRACE', 'RBRACE', 'SEMI') reserved_map = {} t_ignore = ' \t' t_ignore_olcomment = r'(//|\#).*' t_LBRACE = r'\{' t_RBRACE = r'\}' t_SEMI = r';'; def t_newline(self, t): r'\n+' t.lexer.lineno += t.value.count("\n") def t_comment(self, t): r'/\*(.|\n)*?\*/' t.lexer.lineno += t.value.count('\n') def t_DATESUFFIX(self, t): r'(?i)(?<=[0-9 \t])(y(?:ears|ear|ea|e)?|mo(?:nths|nth|nt|n)?|w(?:eeks|eek|ee|e)?|d(?:ays|ay|a)?|h(?:ours|our|ou|o)?|mi(?:nutes|nute|nut|nu|n)?|s(?:econds|econd|econ|eco|ec|e)?)\b' t.value = re.match(r'(?i)(y|mo|w|d|h|mi|s)([a-z]*)', t.value).group(1).lower() return t def t_KEYTYPE(self, t): r'(?i)\b(KSK|ZSK)\b' t.value = t.value.upper() return t def t_ALGNAME(self, t): r'(?i)\b(RSAMD5|DH|DSA|NSEC3DSA|ECC|RSASHA1|NSEC3RSASHA1|RSASHA256|RSASHA512|ECCGOST|ECDSAP256SHA256|ECDSAP384SHA384|ED25519|ED448)\b' t.value = t.value.upper() return t def t_STR(self, t): r'[A-Za-z._-][\w._-]*' t.type = self.reserved_map.get(t.value, "STR") return t def t_QSTRING(self, t): r'"([^"\n]|(\\"))*"' t.type = self.reserved_map.get(t.value, "QSTRING") t.value = t.value[1:-1] return t def t_NUMBER(self, t): r'\d+' t.value = int(t.value) return t def t_error(self, t): print("Illegal character '%s'" % t.value[0]) t.lexer.skip(1) def __init__(self, **kwargs): if 'maketrans' in dir(str): trans = str.maketrans('_', '-') else: trans = maketrans('_', '-') for r in self.reserved: self.reserved_map[r.lower().translate(trans)] = r self.lexer = lex.lex(object=self, **kwargs) def test(self, text): self.lexer.input(text) while True: t = self.lexer.token() if not t: break print(t) ############################################################################ # Policy: this object holds a set of DNSSEC policy settings. ############################################################################ class Policy: is_zone = False is_alg = False is_constructed = False ksk_rollperiod = None zsk_rollperiod = None ksk_prepublish = None zsk_prepublish = None ksk_postpublish = None zsk_postpublish = None ksk_keysize = None zsk_keysize = None ksk_standby = None zsk_standby = None keyttl = None coverage = None directory = None valid_key_sz_per_algo = {'DSA': [512, 1024], 'NSEC3DSA': [512, 1024], 'RSAMD5': [512, 4096], 'RSASHA1': [512, 4096], 'NSEC3RSASHA1': [512, 4096], 'RSASHA256': [512, 4096], 'RSASHA512': [512, 4096], 'ECCGOST': None, 'ECDSAP256SHA256': None, 'ECDSAP384SHA384': None, 'ED25519': None, 'ED448': None} def __init__(self, name=None, algorithm=None, parent=None): self.name = name self.algorithm = algorithm self.parent = parent pass def __repr__(self): return ("%spolicy %s:\n" "\tinherits %s\n" "\tdirectory %s\n" "\talgorithm %s\n" "\tcoverage %s\n" "\tksk_keysize %s\n" "\tzsk_keysize %s\n" "\tksk_rollperiod %s\n" "\tzsk_rollperiod %s\n" "\tksk_prepublish %s\n" "\tksk_postpublish %s\n" "\tzsk_prepublish %s\n" "\tzsk_postpublish %s\n" "\tksk_standby %s\n" "\tzsk_standby %s\n" "\tkeyttl %s\n" % ((self.is_constructed and 'constructed ' or \ self.is_zone and 'zone ' or \ self.is_alg and 'algorithm ' or ''), self.name or 'UNKNOWN', self.parent and self.parent.name or 'None', self.directory and ('"' + str(self.directory) + '"') or 'None', self.algorithm or 'None', self.coverage and str(self.coverage) or 'None', self.ksk_keysize and str(self.ksk_keysize) or 'None', self.zsk_keysize and str(self.zsk_keysize) or 'None', self.ksk_rollperiod and str(self.ksk_rollperiod) or 'None', self.zsk_rollperiod and str(self.zsk_rollperiod) or 'None', self.ksk_prepublish and str(self.ksk_prepublish) or 'None', self.ksk_postpublish and str(self.ksk_postpublish) or 'None', self.zsk_prepublish and str(self.zsk_prepublish) or 'None', self.zsk_postpublish and str(self.zsk_postpublish) or 'None', self.ksk_standby and str(self.ksk_standby) or 'None', self.zsk_standby and str(self.zsk_standby) or 'None', self.keyttl and str(self.keyttl) or 'None')) def __verify_size(self, key_size, size_range): return (size_range[0] <= key_size <= size_range[1]) def get_name(self): return self.name def constructed(self): return self.is_constructed def validate(self): """ Check if the values in the policy make sense :return: True/False if the policy passes validation """ if self.ksk_rollperiod and \ self.ksk_prepublish is not None and \ self.ksk_prepublish > self.ksk_rollperiod: print(self.ksk_rollperiod) return (False, ('KSK pre-publish period (%d) exceeds rollover period %d' % (self.ksk_prepublish, self.ksk_rollperiod))) if self.ksk_rollperiod and \ self.ksk_postpublish is not None and \ self.ksk_postpublish > self.ksk_rollperiod: return (False, ('KSK post-publish period (%d) exceeds rollover period %d' % (self.ksk_postpublish, self.ksk_rollperiod))) if self.zsk_rollperiod and \ self.zsk_prepublish is not None and \ self.zsk_prepublish >= self.zsk_rollperiod: return (False, ('ZSK pre-publish period (%d) exceeds rollover period %d' % (self.zsk_prepublish, self.zsk_rollperiod))) if self.zsk_rollperiod and \ self.zsk_postpublish is not None and \ self.zsk_postpublish >= self.zsk_rollperiod: return (False, ('ZSK post-publish period (%d) exceeds rollover period %d' % (self.zsk_postpublish, self.zsk_rollperiod))) if self.ksk_rollperiod and \ self.ksk_prepublish and self.ksk_postpublish and \ self.ksk_prepublish + self.ksk_postpublish >= self.ksk_rollperiod: return (False, (('KSK pre/post-publish periods (%d/%d) ' + 'combined exceed rollover period %d') % (self.ksk_prepublish, self.ksk_postpublish, self.ksk_rollperiod))) if self.zsk_rollperiod and \ self.zsk_prepublish and self.zsk_postpublish and \ self.zsk_prepublish + self.zsk_postpublish >= self.zsk_rollperiod: return (False, (('ZSK pre/post-publish periods (%d/%d) ' + 'combined exceed rollover period %d') % (self.zsk_prepublish, self.zsk_postpublish, self.zsk_rollperiod))) if self.algorithm is not None: # Validate the key size key_sz_range = self.valid_key_sz_per_algo.get(self.algorithm) if key_sz_range is not None: # Verify KSK if not self.__verify_size(self.ksk_keysize, key_sz_range): return False, 'KSK key size %d outside valid range %s' \ % (self.ksk_keysize, key_sz_range) # Verify ZSK if not self.__verify_size(self.zsk_keysize, key_sz_range): return False, 'ZSK key size %d outside valid range %s' \ % (self.zsk_keysize, key_sz_range) # Specific check for DSA keys if self.algorithm in ['DSA', 'NSEC3DSA'] and \ self.ksk_keysize % 64 != 0: return False, \ ('KSK key size %d not divisible by 64 ' + 'as required for DSA') % self.ksk_keysize if self.algorithm in ['DSA', 'NSEC3DSA'] and \ self.zsk_keysize % 64 != 0: return False, \ ('ZSK key size %d not divisible by 64 ' + 'as required for DSA') % self.zsk_keysize if self.algorithm in ['ECCGOST', \ 'ECDSAP256SHA256', \ 'ECDSAP384SHA384', \ 'ED25519', \ 'ED448']: self.ksk_keysize = None self.zsk_keysize = None return True, '' ############################################################################ # dnssec_policy: # This class reads a dnssec.policy file and creates a dictionary of # DNSSEC policy rules from which a policy for a specific zone can # be generated. ############################################################################ class PolicyException(Exception): pass class dnssec_policy: alg_policy = {} named_policy = {} zone_policy = {} current = None filename = None initial = True def __init__(self, filename=None, **kwargs): self.plex = PolicyLex() self.tokens = self.plex.tokens if 'debug' not in kwargs: kwargs['debug'] = False if 'write_tables' not in kwargs: kwargs['write_tables'] = False self.parser = yacc.yacc(module=self, **kwargs) # set defaults self.setup('''policy global { algorithm rsasha256; key-size ksk 2048; key-size zsk 2048; roll-period ksk 0; roll-period zsk 1y; pre-publish ksk 1mo; pre-publish zsk 1mo; post-publish ksk 1mo; post-publish zsk 1mo; standby ksk 0; standby zsk 0; keyttl 1h; coverage 6mo; }; policy default { policy global; };''') p = Policy() p.algorithm = None p.is_alg = True p.ksk_keysize = 2048; p.zsk_keysize = 2048; # set default algorithm policies # these need a lower default key size: self.alg_policy['DSA'] = copy(p) self.alg_policy['DSA'].algorithm = "DSA" self.alg_policy['DSA'].name = "DSA" self.alg_policy['DSA'].ksk_keysize = 1024; self.alg_policy['NSEC3DSA'] = copy(p) self.alg_policy['NSEC3DSA'].algorithm = "NSEC3DSA" self.alg_policy['NSEC3DSA'].name = "NSEC3DSA" self.alg_policy['NSEC3DSA'].ksk_keysize = 1024; # these can use default settings self.alg_policy['RSAMD5'] = copy(p) self.alg_policy['RSAMD5'].algorithm = "RSAMD5" self.alg_policy['RSAMD5'].name = "RSAMD5" self.alg_policy['RSASHA1'] = copy(p) self.alg_policy['RSASHA1'].algorithm = "RSASHA1" self.alg_policy['RSASHA1'].name = "RSASHA1" self.alg_policy['NSEC3RSASHA1'] = copy(p) self.alg_policy['NSEC3RSASHA1'].algorithm = "NSEC3RSASHA1" self.alg_policy['NSEC3RSASHA1'].name = "NSEC3RSASHA1" self.alg_policy['RSASHA256'] = copy(p) self.alg_policy['RSASHA256'].algorithm = "RSASHA256" self.alg_policy['RSASHA256'].name = "RSASHA256" self.alg_policy['RSASHA512'] = copy(p) self.alg_policy['RSASHA512'].algorithm = "RSASHA512" self.alg_policy['RSASHA512'].name = "RSASHA512" self.alg_policy['ECCGOST'] = copy(p) self.alg_policy['ECCGOST'].algorithm = "ECCGOST" self.alg_policy['ECCGOST'].name = "ECCGOST" self.alg_policy['ECDSAP256SHA256'] = copy(p) self.alg_policy['ECDSAP256SHA256'].algorithm = "ECDSAP256SHA256" self.alg_policy['ECDSAP256SHA256'].name = "ECDSAP256SHA256" self.alg_policy['ECDSAP256SHA256'].ksk_keysize = None; self.alg_policy['ECDSAP256SHA256'].zsk_keysize = None; self.alg_policy['ECDSAP384SHA384'] = copy(p) self.alg_policy['ECDSAP384SHA384'].algorithm = "ECDSAP384SHA384" self.alg_policy['ECDSAP384SHA384'].name = "ECDSAP384SHA384" self.alg_policy['ECDSAP384SHA384'].ksk_keysize = None; self.alg_policy['ECDSAP384SHA384'].zsk_keysize = None; self.alg_policy['ED25519'] = copy(p) self.alg_policy['ED25519'].algorithm = "ED25519" self.alg_policy['ED25519'].name = "ED25519" self.alg_policy['ED25519'].ksk_keysize = None; self.alg_policy['ED25519'].zsk_keysize = None; self.alg_policy['ED448'] = copy(p) self.alg_policy['ED448'].algorithm = "ED448" self.alg_policy['ED448'].name = "ED448" self.alg_policy['ED448'].ksk_keysize = None; self.alg_policy['ED448'].zsk_keysize = None; if filename: self.load(filename) def load(self, filename): self.filename = filename self.initial = True with open(filename) as f: text = f.read() self.plex.lexer.lineno = 0 self.parser.parse(text) self.filename = None def setup(self, text): self.initial = True self.plex.lexer.lineno = 0 self.parser.parse(text) def policy(self, zone, **kwargs): z = zone.lower() p = None if z in self.zone_policy: p = self.zone_policy[z] if p is None: p = copy(self.named_policy['default']) p.name = zone p.is_constructed = True if p.algorithm is None: parent = p.parent or self.named_policy['default'] while parent and not parent.algorithm: parent = parent.parent p.algorithm = parent and parent.algorithm or None if p.algorithm in self.alg_policy: ap = self.alg_policy[p.algorithm] else: raise PolicyException('algorithm not found') if p.directory is None: parent = p.parent or self.named_policy['default'] while parent is not None and not parent.directory: parent = parent.parent p.directory = parent and parent.directory if p.coverage is None: parent = p.parent or self.named_policy['default'] while parent and not parent.coverage: parent = parent.parent p.coverage = parent and parent.coverage or ap.coverage if p.ksk_keysize is None: parent = p.parent or self.named_policy['default'] while parent.parent and not parent.ksk_keysize: parent = parent.parent p.ksk_keysize = parent and parent.ksk_keysize or ap.ksk_keysize if p.zsk_keysize is None: parent = p.parent or self.named_policy['default'] while parent.parent and not parent.zsk_keysize: parent = parent.parent p.zsk_keysize = parent and parent.zsk_keysize or ap.zsk_keysize if p.ksk_rollperiod is None: parent = p.parent or self.named_policy['default'] while parent.parent and not parent.ksk_rollperiod: parent = parent.parent p.ksk_rollperiod = parent and \ parent.ksk_rollperiod or ap.ksk_rollperiod if p.zsk_rollperiod is None: parent = p.parent or self.named_policy['default'] while parent.parent and not parent.zsk_rollperiod: parent = parent.parent p.zsk_rollperiod = parent and \ parent.zsk_rollperiod or ap.zsk_rollperiod if p.ksk_prepublish is None: parent = p.parent or self.named_policy['default'] while parent.parent and not parent.ksk_prepublish: parent = parent.parent p.ksk_prepublish = parent and \ parent.ksk_prepublish or ap.ksk_prepublish if p.zsk_prepublish is None: parent = p.parent or self.named_policy['default'] while parent.parent and not parent.zsk_prepublish: parent = parent.parent p.zsk_prepublish = parent and \ parent.zsk_prepublish or ap.zsk_prepublish if p.ksk_postpublish is None: parent = p.parent or self.named_policy['default'] while parent.parent and not parent.ksk_postpublish: parent = parent.parent p.ksk_postpublish = parent and \ parent.ksk_postpublish or ap.ksk_postpublish if p.zsk_postpublish is None: parent = p.parent or self.named_policy['default'] while parent.parent and not parent.zsk_postpublish: parent = parent.parent p.zsk_postpublish = parent and \ parent.zsk_postpublish or ap.zsk_postpublish if p.keyttl is None: parent = p.parent or self.named_policy['default'] while parent is not None and not parent.keyttl: parent = parent.parent p.keyttl = parent and parent.keyttl if 'novalidate' not in kwargs or not kwargs['novalidate']: (valid, msg) = p.validate() if not valid: raise PolicyException(msg) return None return p def p_policylist(self, p): '''policylist : init policy | policylist policy''' pass def p_init(self, p): "init :" self.initial = False def p_policy(self, p): '''policy : alg_policy | zone_policy | named_policy''' pass def p_name(self, p): '''name : STR | KEYTYPE | DATESUFFIX''' p[0] = p[1] pass def p_domain(self, p): '''domain : STR | QSTRING | KEYTYPE | DATESUFFIX''' p[0] = p[1].strip() if not re.match(r'^[\w.-][\w.-]*$', p[0]): raise PolicyException('invalid domain') pass def p_new_policy(self, p): "new_policy :" self.current = Policy() def p_alg_policy(self, p): "alg_policy : ALGORITHM_POLICY ALGNAME new_policy alg_option_group SEMI" self.current.name = p[2] self.current.is_alg = True self.alg_policy[p[2]] = self.current pass def p_zone_policy(self, p): "zone_policy : ZONE domain new_policy policy_option_group SEMI" self.current.name = p[2].rstrip('.') self.current.is_zone = True self.zone_policy[p[2].rstrip('.').lower()] = self.current pass def p_named_policy(self, p): "named_policy : POLICY name new_policy policy_option_group SEMI" self.current.name = p[2] self.named_policy[p[2].lower()] = self.current pass def p_duration_1(self, p): "duration : NUMBER" p[0] = p[1] pass def p_duration_2(self, p): "duration : NONE" p[0] = None pass def p_duration_3(self, p): "duration : NUMBER DATESUFFIX" if p[2] == "y": p[0] = p[1] * 31536000 # year elif p[2] == "mo": p[0] = p[1] * 2592000 # month elif p[2] == "w": p[0] = p[1] * 604800 # week elif p[2] == "d": p[0] = p[1] * 86400 # day elif p[2] == "h": p[0] = p[1] * 3600 # hour elif p[2] == "mi": p[0] = p[1] * 60 # minute elif p[2] == "s": p[0] = p[1] # second else: raise PolicyException('invalid duration') def p_policy_option_group(self, p): "policy_option_group : LBRACE policy_option_list RBRACE" pass def p_policy_option_list(self, p): '''policy_option_list : policy_option SEMI | policy_option_list policy_option SEMI''' pass def p_policy_option(self, p): '''policy_option : parent_option | directory_option | coverage_option | rollperiod_option | prepublish_option | postpublish_option | keysize_option | algorithm_option | keyttl_option | standby_option''' pass def p_alg_option_group(self, p): "alg_option_group : LBRACE alg_option_list RBRACE" pass def p_alg_option_list(self, p): '''alg_option_list : alg_option SEMI | alg_option_list alg_option SEMI''' pass def p_alg_option(self, p): '''alg_option : coverage_option | rollperiod_option | prepublish_option | postpublish_option | keyttl_option | keysize_option | standby_option''' pass def p_parent_option(self, p): "parent_option : POLICY name" self.current.parent = self.named_policy[p[2].lower()] def p_directory_option(self, p): "directory_option : DIRECTORY QSTRING" self.current.directory = p[2] def p_coverage_option(self, p): "coverage_option : COVERAGE duration" self.current.coverage = p[2] def p_rollperiod_option(self, p): "rollperiod_option : ROLL_PERIOD KEYTYPE duration" if p[2] == "KSK": self.current.ksk_rollperiod = p[3] else: self.current.zsk_rollperiod = p[3] def p_prepublish_option(self, p): "prepublish_option : PRE_PUBLISH KEYTYPE duration" if p[2] == "KSK": self.current.ksk_prepublish = p[3] else: self.current.zsk_prepublish = p[3] def p_postpublish_option(self, p): "postpublish_option : POST_PUBLISH KEYTYPE duration" if p[2] == "KSK": self.current.ksk_postpublish = p[3] else: self.current.zsk_postpublish = p[3] def p_keysize_option(self, p): "keysize_option : KEY_SIZE KEYTYPE NUMBER" if p[2] == "KSK": self.current.ksk_keysize = p[3] else: self.current.zsk_keysize = p[3] def p_standby_option(self, p): "standby_option : STANDBY KEYTYPE NUMBER" if p[2] == "KSK": self.current.ksk_standby = p[3] else: self.current.zsk_standby = p[3] def p_keyttl_option(self, p): "keyttl_option : KEYTTL duration" self.current.keyttl = p[2] def p_algorithm_option(self, p): "algorithm_option : ALGORITHM ALGNAME" self.current.algorithm = p[2] def p_error(self, p): if p: print("%s%s%d:syntax error near '%s'" % (self.filename or "", ":" if self.filename else "", p.lineno, p.value)) else: if not self.initial: raise PolicyException("%s%s%d:unexpected end of input" % (self.filename or "", ":" if self.filename else "", p and p.lineno or 0)) if __name__ == "__main__": import sys if sys.argv[1] == "lex": file = open(sys.argv[2]) text = file.read() file.close() plex = PolicyLex(debug=1) plex.test(text) elif sys.argv[1] == "parse": try: pp = dnssec_policy(sys.argv[2], write_tables=True, debug=True) print(pp.named_policy['default']) print(pp.policy("nonexistent.zone")) except Exception as e: print(e.args[0])