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fw_direct.py
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# -*- coding: utf-8 -*- # # Copyright (C) 2010-2016 Red Hat, Inc. # # Authors: # Thomas Woerner <twoerner@redhat.com> # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. # __all__ = [ "FirewallDirect" ] from firewall.fw_types import LastUpdatedOrderedDict from firewall.core import ipXtables from firewall.core import ebtables from firewall.core.fw_transaction import FirewallTransaction from firewall.core.logger import log from firewall import errors from firewall.errors import FirewallError ############################################################################ # # class Firewall # ############################################################################ class FirewallDirect(object): def __init__(self, fw): self._fw = fw self.__init_vars() def __repr__(self): return '%s(%r, %r, %r)' % (self.__class__, self._chains, self._rules, self._rule_priority_positions) def __init_vars(self): self._chains = { } self._rules = { } self._rule_priority_positions = { } self._passthroughs = { } self._obj = None def cleanup(self): self.__init_vars() # transaction def new_transaction(self): return FirewallTransaction(self._fw) # configuration def set_permanent_config(self, obj): self._obj = obj def has_runtime_configuration(self): if len(self._chains) + len(self._rules) + len(self._passthroughs) > 0: return True return False def has_configuration(self): if self.has_runtime_configuration(): return True if len(self._obj.get_all_chains()) + \ len(self._obj.get_all_rules()) + \ len(self._obj.get_all_passthroughs()) > 0: return True return False def apply_direct(self, use_transaction=None): if use_transaction is None: transaction = self.new_transaction() else: transaction = use_transaction # Apply permanent configuration and save the obj to be able to # remove permanent configuration settings within get_runtime_config # for use in firewalld reload. self.set_config((self._obj.get_all_chains(), self._obj.get_all_rules(), self._obj.get_all_passthroughs()), transaction) if use_transaction is None: transaction.execute(True) def get_runtime_config(self): # Return only runtime changes # Remove all chains, rules and passthroughs that are in self._obj # (permanent config applied in firewalld _start. chains = { } rules = { } passthroughs = { } for table_id in self._chains: (ipv, table) = table_id for chain in self._chains[table_id]: if not self._obj.query_chain(ipv, table, chain): chains.setdefault(table_id, [ ]).append(chain) for chain_id in self._rules: (ipv, table, chain) = chain_id for (priority, args) in self._rules[chain_id]: if not self._obj.query_rule(ipv, table, chain, priority, args): if chain_id not in rules: rules[chain_id] = LastUpdatedOrderedDict() rules[chain_id][(priority, args)] = priority for ipv in self._passthroughs: for args in self._passthroughs[ipv]: if not self._obj.query_passthrough(ipv, args): if ipv not in passthroughs: passthroughs[ipv] = [ ] passthroughs[ipv].append(args) return (chains, rules, passthroughs) def get_config(self): return (self._chains, self._rules, self._passthroughs) def set_config(self, conf, use_transaction=None): if use_transaction is None: transaction = self.new_transaction() else: transaction = use_transaction (_chains, _rules, _passthroughs) = conf for table_id in _chains: (ipv, table) = table_id for chain in _chains[table_id]: if not self.query_chain(ipv, table, chain): try: self.add_chain(ipv, table, chain, use_transaction=transaction) except FirewallError as error: log.warning(str(error)) for chain_id in _rules: (ipv, table, chain) = chain_id for (priority, args) in _rules[chain_id]: if not self.query_rule(ipv, table, chain, priority, args): try: self.add_rule(ipv, table, chain, priority, args, use_transaction=transaction) except FirewallError as error: log.warning(str(error)) for ipv in _passthroughs: for args in _passthroughs[ipv]: if not self.query_passthrough(ipv, args): try: self.add_passthrough(ipv, args, use_transaction=transaction) except FirewallError as error: log.warning(str(error)) if use_transaction is None: transaction.execute(True) def _check_ipv(self, ipv): ipvs = ['ipv4', 'ipv6', 'eb'] if ipv not in ipvs: raise FirewallError(errors.INVALID_IPV, "'%s' not in '%s'" % (ipv, ipvs)) def _check_ipv_table(self, ipv, table): self._check_ipv(ipv) tables = ipXtables.BUILT_IN_CHAINS.keys() if ipv in [ 'ipv4', 'ipv6' ] \ else ebtables.BUILT_IN_CHAINS.keys() if table not in tables: raise FirewallError(errors.INVALID_TABLE, "'%s' not in '%s'" % (table, tables)) def _check_builtin_chain(self, ipv, table, chain): if ipv in ['ipv4', 'ipv6']: built_in_chains = ipXtables.BUILT_IN_CHAINS[table] if self._fw.nftables_enabled: our_chains = {} else: our_chains = self._fw.get_direct_backend_by_ipv(ipv).our_chains[table] else: built_in_chains = ebtables.BUILT_IN_CHAINS[table] our_chains = ebtables.OUR_CHAINS[table] if chain in built_in_chains: raise FirewallError(errors.BUILTIN_CHAIN, "chain '%s' is built-in chain" % chain) if chain in our_chains: raise FirewallError(errors.BUILTIN_CHAIN, "chain '%s' is reserved" % chain) if ipv in [ "ipv4", "ipv6" ]: if self._fw.zone.zone_from_chain(chain) is not None: raise FirewallError(errors.INVALID_CHAIN, "Chain '%s' is reserved" % chain) def _register_chain(self, table_id, chain, add): if add: self._chains.setdefault(table_id, [ ]).append(chain) else: self._chains[table_id].remove(chain) if len(self._chains[table_id]) == 0: del self._chains[table_id] def add_chain(self, ipv, table, chain, use_transaction=None): if use_transaction is None: transaction = self.new_transaction() else: transaction = use_transaction if self._fw.may_skip_flush_direct_backends(): transaction.add_pre(self._fw.flush_direct_backends) #TODO: policy="ACCEPT" self._chain(True, ipv, table, chain, transaction) if use_transaction is None: transaction.execute(True) def remove_chain(self, ipv, table, chain, use_transaction=None): if use_transaction is None: transaction = self.new_transaction() else: transaction = use_transaction self._chain(False, ipv, table, chain, transaction) if use_transaction is None: transaction.execute(True) def query_chain(self, ipv, table, chain): self._check_ipv_table(ipv, table) self._check_builtin_chain(ipv, table, chain) table_id = (ipv, table) return (table_id in self._chains and chain in self._chains[table_id]) def get_chains(self, ipv, table): self._check_ipv_table(ipv, table) table_id = (ipv, table) if table_id in self._chains: return self._chains[table_id] return [ ] def get_all_chains(self): r = [ ] for key in self._chains: (ipv, table) = key for chain in self._chains[key]: r.append((ipv, table, chain)) return r def add_rule(self, ipv, table, chain, priority, args, use_transaction=None): if use_transaction is None: transaction = self.new_transaction() else: transaction = use_transaction if self._fw.may_skip_flush_direct_backends(): transaction.add_pre(self._fw.flush_direct_backends) self._rule(True, ipv, table, chain, priority, args, transaction) if use_transaction is None: transaction.execute(True) def remove_rule(self, ipv, table, chain, priority, args, use_transaction=None): if use_transaction is None: transaction = self.new_transaction() else: transaction = use_transaction self._rule(False, ipv, table, chain, priority, args, transaction) if use_transaction is None: transaction.execute(True) def query_rule(self, ipv, table, chain, priority, args): self._check_ipv_table(ipv, table) chain_id = (ipv, table, chain) return chain_id in self._rules and \ (priority, args) in self._rules[chain_id] def get_rules(self, ipv, table, chain): self._check_ipv_table(ipv, table) chain_id = (ipv, table, chain) if chain_id in self._rules: return list(self._rules[chain_id].keys()) return [ ] def get_all_rules(self): r = [ ] for key in self._rules: (ipv, table, chain) = key for (priority, args) in self._rules[key]: r.append((ipv, table, chain, priority, list(args))) return r def _register_rule(self, rule_id, chain_id, priority, enable, count): if enable: if chain_id not in self._rules: self._rules[chain_id] = LastUpdatedOrderedDict() self._rules[chain_id][rule_id] = priority if chain_id not in self._rule_priority_positions: self._rule_priority_positions[chain_id] = { } if priority in self._rule_priority_positions[chain_id]: self._rule_priority_positions[chain_id][priority] += count else: self._rule_priority_positions[chain_id][priority] = count else: del self._rules[chain_id][rule_id] if len(self._rules[chain_id]) == 0: del self._rules[chain_id] self._rule_priority_positions[chain_id][priority] -= count # DIRECT PASSTHROUGH (untracked) def passthrough(self, ipv, args): try: return self._fw.rule(self._fw.get_direct_backend_by_ipv(ipv).name, args) except Exception as msg: log.debug2(msg) raise FirewallError(errors.COMMAND_FAILED, msg) def _register_passthrough(self, ipv, args, enable): if enable: if ipv not in self._passthroughs: self._passthroughs[ipv] = [ ] self._passthroughs[ipv].append(args) else: self._passthroughs[ipv].remove(args) if len(self._passthroughs[ipv]) == 0: del self._passthroughs[ipv] def add_passthrough(self, ipv, args, use_transaction=None): if use_transaction is None: transaction = self.new_transaction() else: transaction = use_transaction if self._fw.may_skip_flush_direct_backends(): transaction.add_pre(self._fw.flush_direct_backends) self._passthrough(True, ipv, list(args), transaction) if use_transaction is None: transaction.execute(True) def remove_passthrough(self, ipv, args, use_transaction=None): if use_transaction is None: transaction = self.new_transaction() else: transaction = use_transaction self._passthrough(False, ipv, list(args), transaction) if use_transaction is None: transaction.execute(True) def query_passthrough(self, ipv, args): return ipv in self._passthroughs and \ tuple(args) in self._passthroughs[ipv] def get_all_passthroughs(self): r = [ ] for ipv in self._passthroughs: for args in self._passthroughs[ipv]: r.append((ipv, list(args))) return r def get_passthroughs(self, ipv): r = [ ] if ipv in self._passthroughs: for args in self._passthroughs[ipv]: r.append(list(args)) return r def split_value(self, rules, opts): """Split values combined with commas for options in opts""" out_rules = [ ] for rule in rules: processed = False for opt in opts: try: i = rule.index(opt) except ValueError: pass else: if len(rule) > i and "," in rule[i+1]: # For all items in the comma separated list in index # i of the rule, a new rule is created with a single # item from this list processed = True items = rule[i+1].split(",") for item in items: _rule = rule[:] _rule[i+1] = item out_rules.append(_rule) if not processed: out_rules.append(rule) return out_rules def _rule(self, enable, ipv, table, chain, priority, args, transaction): self._check_ipv_table(ipv, table) # Do not create zone chains if we're using nftables. Only allow direct # rules in the built in chains. if not self._fw.nftables_enabled \ and ipv in [ "ipv4", "ipv6" ]: self._fw.zone.create_zone_base_by_chain(ipv, table, chain, transaction) _chain = chain backend = self._fw.get_direct_backend_by_ipv(ipv) # if nftables is in use, just put the direct rules in the chain # specified by the user. i.e. don't append _direct. if not self._fw.nftables_enabled \ and backend.is_chain_builtin(ipv, table, chain): _chain = "%s_direct" % (chain) elif self._fw.nftables_enabled and chain[-7:] == "_direct" \ and backend.is_chain_builtin(ipv, table, chain[:-7]): # strip _direct suffix. If we're using nftables we don't bother # creating the *_direct chains for builtin chains. _chain = chain[:-7] chain_id = (ipv, table, chain) rule_id = (priority, args) if enable: if chain_id in self._rules and \ rule_id in self._rules[chain_id]: raise FirewallError(errors.ALREADY_ENABLED, "rule '%s' already is in '%s:%s:%s'" % \ (args, ipv, table, chain)) else: if chain_id not in self._rules or \ rule_id not in self._rules[chain_id]: raise FirewallError(errors.NOT_ENABLED, "rule '%s' is not in '%s:%s:%s'" % \ (args, ipv, table, chain)) # get priority of rule priority = self._rules[chain_id][rule_id] # If a rule gets added, the initial rule index position within the # ipv, table and chain combination (chain_id) is 1. # Tf the chain_id exists in _rule_priority_positions, there are already # other rules for this chain_id. The number of rules for a priority # less or equal to the priority of the new rule will increase the # index of the new rule. The index is the ip*tables -I insert rule # number. # # Example: We have the following rules for chain_id (ipv4, filter, # INPUT) already: # ipv4, filter, INPUT, 1, -i, foo1, -j, ACCEPT # ipv4, filter, INPUT, 2, -i, foo2, -j, ACCEPT # ipv4, filter, INPUT, 2, -i, foo2_1, -j, ACCEPT # ipv4, filter, INPUT, 3, -i, foo3, -j, ACCEPT # This results in the following _rule_priority_positions structure: # _rule_priority_positions[(ipv4,filter,INPUT)][1] = 1 # _rule_priority_positions[(ipv4,filter,INPUT)][2] = 2 # _rule_priority_positions[(ipv4,filter,INPUT)][3] = 1 # The new rule # ipv4, filter, INPUT, 2, -i, foo2_2, -j, ACCEPT # has the same pritority as the second rule before and will be added # right after it. # The initial index is 1 and the chain_id is already in # _rule_priority_positions. Therefore the index will increase for # the number of rules in every rule position in # _rule_priority_positions[(ipv4,filter,INPUT)].keys() # where position is smaller or equal to the entry in keys. # With the example from above: # The priority of the new rule is 2. Therefore for all keys in # _rule_priority_positions[chain_id] where priority is 1 or 2, the # number of the rules will increase the index of the rule. # For _rule_priority_positions[chain_id][1]: index += 1 # _rule_priority_positions[chain_id][2]: index += 2 # index will be 4 in the end and the rule in the table chain # combination will be added at index 4. # If there are no rules in the table chain combination, a new rule # has index 1. index = 1 count = 0 if chain_id in self._rule_priority_positions: positions = sorted(self._rule_priority_positions[chain_id].keys()) j = 0 while j < len(positions) and priority >= positions[j]: index += self._rule_priority_positions[chain_id][positions[j]] j += 1 # split the direct rule in some cases as iptables-restore can't handle # compound args. # args_list = [list(args)] args_list = self.split_value(args_list, [ "-s", "--source" ]) args_list = self.split_value(args_list, [ "-d", "--destination" ]) for _args in args_list: transaction.add_rule(backend, backend.build_rule(enable, table, _chain, index, tuple(_args))) index += 1 count += 1 self._register_rule(rule_id, chain_id, priority, enable, count) transaction.add_fail(self._register_rule, rule_id, chain_id, priority, not enable, count) def _chain(self, add, ipv, table, chain, transaction): self._check_ipv_table(ipv, table) self._check_builtin_chain(ipv, table, chain) table_id = (ipv, table) if add: if table_id in self._chains and \ chain in self._chains[table_id]: raise FirewallError(errors.ALREADY_ENABLED, "chain '%s' already is in '%s:%s'" % \ (chain, ipv, table)) else: if table_id not in self._chains or \ chain not in self._chains[table_id]: raise FirewallError(errors.NOT_ENABLED, "chain '%s' is not in '%s:%s'" % \ (chain, ipv, table)) backend = self._fw.get_direct_backend_by_ipv(ipv) transaction.add_rules(backend, backend.build_chain_rules(add, table, chain)) self._register_chain(table_id, chain, add) transaction.add_fail(self._register_chain, table_id, chain, not add) def _passthrough(self, enable, ipv, args, transaction): self._check_ipv(ipv) tuple_args = tuple(args) if enable: if ipv in self._passthroughs and \ tuple_args in self._passthroughs[ipv]: raise FirewallError(errors.ALREADY_ENABLED, "passthrough '%s', '%s'" % (ipv, args)) else: if ipv not in self._passthroughs or \ tuple_args not in self._passthroughs[ipv]: raise FirewallError(errors.NOT_ENABLED, "passthrough '%s', '%s'" % (ipv, args)) backend = self._fw.get_direct_backend_by_ipv(ipv) if enable: backend.check_passthrough(args) # try to find out if a zone chain should be used if ipv in [ "ipv4", "ipv6" ]: table, chain = backend.passthrough_parse_table_chain(args) if table and chain: self._fw.zone.create_zone_base_by_chain(ipv, table, chain) _args = args else: _args = backend.reverse_passthrough(args) transaction.add_rule(backend, _args) self._register_passthrough(ipv, tuple_args, enable) transaction.add_fail(self._register_passthrough, ipv, tuple_args, not enable)