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# -*- coding: utf-8 -*- # # Copyright (C) 2015-2016 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/>. # """The ipset command wrapper""" __all__ = [ "ipset", "check_ipset_name", "remove_default_create_options" ] import os.path import ipaddress from firewall import errors from firewall.errors import FirewallError from firewall.core.prog import runProg from firewall.core.logger import log from firewall.functions import tempFile, readfile from firewall.config import COMMANDS IPSET_MAXNAMELEN = 32 IPSET_TYPES = [ # bitmap and set types are currently not supported # "bitmap:ip", # "bitmap:ip,mac", # "bitmap:port", # "list:set", "hash:ip", "hash:ip,port", "hash:ip,port,ip", "hash:ip,port,net", "hash:ip,mark", "hash:net", "hash:net,net", "hash:net,port", "hash:net,port,net", "hash:net,iface", "hash:mac", ] IPSET_CREATE_OPTIONS = { "family": "inet|inet6", "hashsize": "value", "maxelem": "value", "timeout": "value in secs", #"counters": None, #"comment": None, } IPSET_DEFAULT_CREATE_OPTIONS = { "family": "inet", "hashsize": "1024", "maxelem": "65536", } class ipset(object): """ipset command wrapper class""" def __init__(self): self._command = COMMANDS["ipset"] self.name = "ipset" def __run(self, args): """Call ipset with args""" # convert to string list _args = ["%s" % item for item in args] log.debug2("%s: %s %s", self.__class__, self._command, " ".join(_args)) (status, ret) = runProg(self._command, _args) if status != 0: raise ValueError("'%s %s' failed: %s" % (self._command, " ".join(_args), ret)) return ret def check_name(self, name): """Check ipset name""" if len(name) > IPSET_MAXNAMELEN: raise FirewallError(errors.INVALID_NAME, "ipset name '%s' is not valid" % name) def set_supported_types(self): """Return types that are supported by the ipset command and kernel""" ret = [ ] output = "" try: output = self.__run(["--help"]) except ValueError as ex: log.debug1("ipset error: %s" % ex) lines = output.splitlines() in_types = False for line in lines: #print(line) if in_types: splits = line.strip().split(None, 2) if splits[0] not in ret and splits[0] in IPSET_TYPES: ret.append(splits[0]) if line.startswith("Supported set types:"): in_types = True return ret def check_type(self, type_name): """Check ipset type""" if len(type_name) > IPSET_MAXNAMELEN or type_name not in IPSET_TYPES: raise FirewallError(errors.INVALID_TYPE, "ipset type name '%s' is not valid" % type_name) def set_create(self, set_name, type_name, options=None): """Create an ipset with name, type and options""" self.check_name(set_name) self.check_type(type_name) args = [ "create", set_name, type_name ] if isinstance(options, dict): for key, val in options.items(): args.append(key) if val != "": args.append(val) return self.__run(args) def set_destroy(self, set_name): self.check_name(set_name) return self.__run([ "destroy", set_name ]) def set_add(self, set_name, entry): args = [ "add", set_name, entry ] return self.__run(args) def set_delete(self, set_name, entry): args = [ "del", set_name, entry ] return self.__run(args) def test(self, set_name, entry, options=None): args = [ "test", set_name, entry ] if options: args.append("%s" % " ".join(options)) return self.__run(args) def set_list(self, set_name=None, options=None): args = [ "list" ] if set_name: args.append(set_name) if options: args.extend(options) return self.__run(args).split("\n") def set_get_active_terse(self): """ Get active ipsets (only headers) """ lines = self.set_list(options=["-terse"]) ret = { } _name = _type = None _options = { } for line in lines: if len(line) < 1: continue pair = [ x.strip() for x in line.split(":", 1) ] if len(pair) != 2: continue elif pair[0] == "Name": _name = pair[1] elif pair[0] == "Type": _type = pair[1] elif pair[0] == "Header": splits = pair[1].split() i = 0 while i < len(splits): opt = splits[i] if opt in [ "family", "hashsize", "maxelem", "timeout", "netmask" ]: if len(splits) > i: i += 1 _options[opt] = splits[i] else: log.error("Malformed ipset list -terse output: %s", line) return { } i += 1 if _name and _type: ret[_name] = (_type, remove_default_create_options(_options)) _name = _type = None _options.clear() return ret def save(self, set_name=None): args = [ "save" ] if set_name: args.append(set_name) return self.__run(args) def set_restore(self, set_name, type_name, entries, create_options=None, entry_options=None): self.check_name(set_name) self.check_type(type_name) temp_file = tempFile() if ' ' in set_name: set_name = "'%s'" % set_name args = [ "create", set_name, type_name, "-exist" ] if create_options: for key, val in create_options.items(): args.append(key) if val != "": args.append(val) temp_file.write("%s\n" % " ".join(args)) temp_file.write("flush %s\n" % set_name) for entry in entries: if ' ' in entry: entry = "'%s'" % entry if entry_options: temp_file.write("add %s %s %s\n" % \ (set_name, entry, " ".join(entry_options))) else: temp_file.write("add %s %s\n" % (set_name, entry)) temp_file.close() stat = os.stat(temp_file.name) log.debug2("%s: %s restore %s", self.__class__, self._command, "%s: %d" % (temp_file.name, stat.st_size)) args = [ "restore" ] (status, ret) = runProg(self._command, args, stdin=temp_file.name) if log.getDebugLogLevel() > 2: try: readfile(temp_file.name) except Exception: pass else: i = 1 for line in readfile(temp_file.name): log.debug3("%8d: %s" % (i, line), nofmt=1, nl=0) if not line.endswith("\n"): log.debug3("", nofmt=1) i += 1 os.unlink(temp_file.name) if status != 0: raise ValueError("'%s %s' failed: %s" % (self._command, " ".join(args), ret)) return ret def set_flush(self, set_name): args = [ "flush" ] if set_name: args.append(set_name) return self.__run(args) def rename(self, old_set_name, new_set_name): return self.__run([ "rename", old_set_name, new_set_name ]) def swap(self, set_name_1, set_name_2): return self.__run([ "swap", set_name_1, set_name_2 ]) def version(self): return self.__run([ "version" ]) def check_ipset_name(name): """Return true if ipset name is valid""" if len(name) > IPSET_MAXNAMELEN: return False return True def remove_default_create_options(options): """ Return only non default create options """ _options = options.copy() for opt in IPSET_DEFAULT_CREATE_OPTIONS: if opt in _options and \ IPSET_DEFAULT_CREATE_OPTIONS[opt] == _options[opt]: del _options[opt] return _options def normalize_ipset_entry(entry): """ Normalize IP addresses in entry """ _entry = [] for _part in entry.split(","): try: _part.index("/") _entry.append(str(ipaddress.ip_network(_part, strict=False))) except ValueError: _entry.append(_part) return ",".join(_entry) def check_entry_overlaps_existing(entry, entries): """ Check if entry overlaps any entry in the list of entries """ # Only check simple types if len(entry.split(",")) > 1: return try: entry_network = ipaddress.ip_network(entry, strict=False) except ValueError: # could not parse the new IP address, maybe a MAC return for itr in entries: if entry_network.overlaps(ipaddress.ip_network(itr, strict=False)): raise FirewallError(errors.INVALID_ENTRY, "Entry '{}' overlaps with existing entry '{}'".format(entry, itr)) def check_for_overlapping_entries(entries): """ Check if any entry overlaps any entry in the list of entries """ try: entries = [ipaddress.ip_network(x, strict=False) for x in entries] except ValueError: # at least one entry can not be parsed return if len(entries) == 0: return # We can take advantage of some facts of IPv4Network/IPv6Network and # how Python sorts the networks to quickly detect overlaps. # # Facts: # # 1. IPv{4,6}Network are normalized to remove host bits, e.g. # 10.1.1.0/16 will become 10.1.0.0/16. # # 2. IPv{4,6}Network objects are sorted by: # a. IP address (network bits) # then # b. netmask (significant bits count) # # Because of the above we have these properties: # # 1. big networks (netA) are sorted before smaller networks (netB) # that overlap the big network (netA) # - e.g. 10.1.128.0/17 (netA) sorts before 10.1.129.0/24 (netB) # 2. same value addresses (network bits) are grouped together even # if the number of network bits vary. e.g. /16 vs /24 # - recall that address are normalized to remove host bits # - e.g. 10.1.128.0/17 (netA) sorts before 10.1.128.0/24 (netC) # 3. non-overlapping networks (netD, netE) are always sorted before or # after networks that overlap (netB, netC) the current one (netA) # - e.g. 10.1.128.0/17 (netA) sorts before 10.2.128.0/16 (netD) # - e.g. 10.1.128.0/17 (netA) sorts after 9.1.128.0/17 (netE) # - e.g. 9.1.128.0/17 (netE) sorts before 10.1.129.0/24 (netB) # # With this we know the sorted list looks like: # # list: [ netE, netA, netB, netC, netD ] # # netE = non-overlapping network # netA = big network # netB = smaller network that overlaps netA (subnet) # netC = smaller network that overlaps netA (subnet) # netD = non-overlapping network # # If networks netB and netC exist in the list, they overlap and are # adjacent to netA. # # Checking for overlaps on a sorted list is thus: # # 1. compare adjacent elements in the list for overlaps # # Recall that we only need to detect a single overlap. We do not need to # detect them all. # entries.sort() prev_network = entries.pop(0) for current_network in entries: if prev_network.overlaps(current_network): raise FirewallError(errors.INVALID_ENTRY, "Entry '{}' overlaps entry '{}'".format(prev_network, current_network)) prev_network = current_network