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backend_iptables.py
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'''backend_iptables.py: iptables backend for ufw''' # # Copyright 2008-2018 Canonical Ltd. # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License version 3, # as published by the Free Software Foundation. # # 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/>. # import os import re import shutil import stat import sys import time from ufw.common import UFWError, UFWRule from ufw.util import warn, debug, msg, cmd, cmd_pipe, _findpath import ufw.backend class UFWBackendIptables(ufw.backend.UFWBackend): '''Instance class for UFWBackend''' def __init__(self, dryrun, rootdir=None, datadir=None): '''UFWBackendIptables initialization''' self.comment_str = "# " + ufw.common.programName + "_comment #" self.rootdir = rootdir self.datadir = datadir files = {} config_dir = _findpath(ufw.common.config_dir, datadir) state_dir = _findpath(ufw.common.state_dir, datadir) files['rules'] = os.path.join(config_dir, 'ufw/user.rules') files['before_rules'] = os.path.join(config_dir, 'ufw/before.rules') files['after_rules'] = os.path.join(config_dir, 'ufw/after.rules') files['rules6'] = os.path.join(config_dir, 'ufw/user6.rules') files['before6_rules'] = os.path.join(config_dir, 'ufw/before6.rules') files['after6_rules'] = os.path.join(config_dir, 'ufw/after6.rules') files['init'] = os.path.join(state_dir, 'ufw-init') ufw.backend.UFWBackend.__init__(self, "iptables", dryrun, files, rootdir=rootdir, datadir=datadir) self.chains = {'before': [], 'user': [], 'after': [], 'misc': []} for ver in ['4', '6']: chain_prefix = "ufw" if ver == "6": if self.use_ipv6(): chain_prefix += ver elif ver == "6": continue for loc in ['before', 'user', 'after']: for target in ['input', 'output', 'forward']: chain = "%s-%s-logging-%s" % (chain_prefix, loc, target) self.chains[loc].append(chain) self.chains['misc'].append(chain_prefix + "-logging-deny") self.chains['misc'].append(chain_prefix + "-logging-allow") # The default log rate limiting rule ('ufw[6]-user-limit chain should # be prepended before use) self.ufw_user_limit_log = ['-m', 'limit', \ '--limit', '3/minute', '-j', 'LOG', \ '--log-prefix'] self.ufw_user_limit_log_text = "[UFW LIMIT BLOCK]" def get_default_application_policy(self): '''Get current policy''' rstr = _("New profiles:") if self.defaults['default_application_policy'] == "accept": rstr += " allow" elif self.defaults['default_application_policy'] == "drop": rstr += " deny" elif self.defaults['default_application_policy'] == "reject": rstr += " reject" else: rstr += " skip" return rstr def set_default_policy(self, policy, direction): '''Sets default policy of firewall''' if not self.dryrun: if policy != "allow" and policy != "deny" and policy != "reject": err_msg = _("Unsupported policy '%s'") % (policy) raise UFWError(err_msg) if direction != "incoming" and direction != "outgoing" and \ direction != "routed": err_msg = _("Unsupported policy for direction '%s'") % \ (direction) raise UFWError(err_msg) chain = "INPUT" if direction == "outgoing": chain = "OUTPUT" elif direction == "routed": chain = "FORWARD" old_log_str = '' new_log_str = '' if policy == "allow": try: self.set_default(self.files['defaults'], \ "DEFAULT_%s_POLICY" % (chain), \ "\"ACCEPT\"") except Exception: raise old_log_str = 'UFW BLOCK' new_log_str = 'UFW ALLOW' elif policy == "reject": try: self.set_default(self.files['defaults'], \ "DEFAULT_%s_POLICY" % (chain), \ "\"REJECT\"") except Exception: raise old_log_str = 'UFW ALLOW' new_log_str = 'UFW BLOCK' else: try: self.set_default(self.files['defaults'], \ "DEFAULT_%s_POLICY" % (chain), \ "\"DROP\"") except Exception: raise old_log_str = 'UFW ALLOW' new_log_str = 'UFW BLOCK' # Switch logging message in catch-all rules pat = re.compile(r'' + old_log_str) for f in [self.files['after_rules'], self.files['after6_rules']]: try: fns = ufw.util.open_files(f) except Exception: raise fd = fns['tmp'] for line in fns['orig']: if pat.search(line): ufw.util.write_to_file(fd, pat.sub(new_log_str, line)) else: ufw.util.write_to_file(fd, line) try: ufw.util.close_files(fns) except Exception: raise rstr = _("Default %(direction)s policy changed to '%(policy)s'\n") % \ ({'direction': direction, 'policy': policy}) rstr += _("(be sure to update your rules accordingly)") return rstr def get_running_raw(self, rules_type): '''Show current running status of firewall''' if self.dryrun: out = "> " + _("Checking raw iptables\n") out += "> " + _("Checking raw ip6tables\n") return out # Initialize the capabilities database self.initcaps() args = ['-n', '-v', '-x', '-L'] items = [] items6 = [] if rules_type == "raw": args.append('-t') items = ['filter', 'nat', 'mangle', 'raw'] items6 = ['filter', 'mangle', 'raw'] elif rules_type == "builtins": for c in ['INPUT', 'FORWARD', 'OUTPUT']: items.append('filter:%s' % c) items6.append('filter:%s' % c) for c in ['PREROUTING', 'INPUT', 'FORWARD', 'OUTPUT', \ 'POSTROUTING']: items.append('mangle:%s' % c) items6.append('mangle:%s' % c) for c in ['PREROUTING', 'OUTPUT']: items.append('raw:%s' % c) items6.append('raw:%s' % c) for c in ['PREROUTING', 'POSTROUTING', 'OUTPUT']: items.append('nat:%s' % c) elif rules_type == "before": for b in ['input', 'forward', 'output']: items.append('ufw-before-%s' % b) items6.append('ufw6-before-%s' % b) elif rules_type == "user": for b in ['input', 'forward', 'output']: items.append('ufw-user-%s' % b) items6.append('ufw6-user-%s' % b) if self.caps['limit']['4']: items.append('ufw-user-limit-accept') items.append('ufw-user-limit') if self.caps['limit']['6']: items6.append('ufw6-user-limit-accept') items6.append('ufw6-user-limit') elif rules_type == "after": for b in ['input', 'forward', 'output']: items.append('ufw-after-%s' % b) items6.append('ufw6-after-%s' % b) elif rules_type == "logging": for b in ['input', 'forward', 'output']: items.append('ufw-before-logging-%s' % b) items6.append('ufw6-before-logging-%s' % b) items.append('ufw-user-logging-%s' % b) items6.append('ufw6-user-logging-%s' % b) items.append('ufw-after-logging-%s' % b) items6.append('ufw6-after-logging-%s' % b) items.append('ufw-logging-allow') items.append('ufw-logging-deny') items6.append('ufw6-logging-allow') items6.append('ufw6-logging-deny') out = "IPV4 (%s):\n" % (rules_type) for i in items: if ':' in i: (t, c) = i.split(':') out += "(%s) " % (t) (rc, tmp) = cmd([self.iptables] + args + [c, '-t', t]) else: (rc, tmp) = cmd([self.iptables] + args + [i]) out += tmp if rules_type != "raw": out += "\n" if rc != 0: raise UFWError(out) if rules_type == "raw" or self.use_ipv6(): out += "\n\nIPV6:\n" for i in items6: if ':' in i: (t, c) = i.split(':') out += "(%s) " % (t) (rc, tmp) = cmd([self.iptables] + args + [c, '-t', t]) else: (rc, tmp) = cmd([self.ip6tables] + args + [i]) out += tmp if rules_type != "raw": out += "\n" if rc != 0: raise UFWError(out) return out def get_status(self, verbose=False, show_count=False): '''Show ufw managed rules''' out = "" if self.dryrun: out = "> " + _("Checking iptables\n") if self.use_ipv6(): out += "> " + _("Checking ip6tables\n") return out err_msg = _("problem running") for direction in ["input", "output", "forward"]: # Is the firewall loaded at all? (rc, out) = cmd([self.iptables, '-L', \ 'ufw-user-%s' % (direction), '-n']) if rc == 1: return _("Status: inactive") elif rc != 0: raise UFWError(err_msg + " iptables: %s\n" % (out)) if self.use_ipv6(): (rc, out6) = cmd([self.ip6tables, '-L', \ 'ufw6-user-%s' % (direction), '-n']) if rc != 0: raise UFWError(err_msg + " ip6tables") s = "" str_out = "" str_rte = "" rules = self.rules + self.rules6 count = 1 app_rules = {} for r in rules: tmp_str = "" location = {} tupl = "" show_proto = True if not verbose and (r.dapp != "" or r.sapp != ""): show_proto = False tupl = r.get_app_tuple() if tupl in app_rules: debug("Skipping found tuple '%s'" % (tupl)) continue else: app_rules[tupl] = True for loc in [ 'dst', 'src' ]: location[loc] = "" port = "" tmp = "" if loc == "dst": tmp = r.dst if not verbose and r.dapp != "": port = r.dapp if r.v6 and tmp == "::/0": port += " (v6)" else: port = r.dport else: tmp = r.src if not verbose and r.sapp != "": port = r.sapp if r.v6 and tmp == "::/0": port += " (v6)" else: port = r.sport if tmp != "0.0.0.0/0" and tmp != "::/0": location[loc] = tmp if port != "any": if location[loc] == "": location[loc] = port else: location[loc] += " " + port if show_proto and r.protocol != "any": location[loc] += "/" + r.protocol if verbose: if loc == "dst" and r.dapp != "": location[loc] += " (%s" % (r.dapp) if r.v6 and tmp == "::/0": location[loc] += " (v6)" location[loc] += ")" if loc == "src" and r.sapp != "": location[loc] += " (%s" % (r.sapp) if r.v6 and tmp == "::/0": location[loc] += " (v6)" location[loc] += ")" if port == "any": if tmp == "0.0.0.0/0" or tmp == "::/0": location[loc] = "Anywhere" # Show the protocol if Anywhere to Anwhere, have # protocol and source and dest ports are any if show_proto and r.protocol != "any" and \ r.dst == r.src and r.dport == r.sport: location[loc] += "/" + r.protocol if tmp == "::/0": location[loc] += " (v6)" else: # Show the protocol if have protocol, and source # and dest ports are any if show_proto and r.protocol != "any" and \ r.dport == r.sport: location[loc] += "/" + r.protocol elif r.v6 and r.src == "::/0" and r.dst == "::/0" \ and ' (v6)' not in location[loc]: # Add v6 if have port but no addresses so it doesn't look # a duplicate of the v4 rule location[loc] += " (v6)" # Reporting the interfaces is different in route rules and # non-route rules. With route rules, the reporting should be # relative to how packets flow through the firewall, with # other rules the reporting should be relative to the firewall # system as endpoint. As such, for route rules, report the # incoming interface under 'From' and the outgoing interface # under 'To', and for non-route rules, report the incoming # interface under 'To', and the outgoing interface under # 'From'. if r.forward: if loc == 'src' and r.interface_in != "": location[loc] += " on %s" % (r.interface_in) if loc == 'dst' and r.interface_out != "": location[loc] += " on %s" % (r.interface_out) else: if loc == 'dst' and r.interface_in != "": location[loc] += " on %s" % (r.interface_in) if loc == 'src' and r.interface_out != "": location[loc] += " on %s" % (r.interface_out) attribs = [] attrib_str = "" if r.logtype or r.direction.lower() == "out": if r.logtype: attribs.append(r.logtype.lower()) # why is the direction added to attribs if shown in action? if show_count and r.direction == "out": attribs.append(r.direction) if len(attribs) > 0: attrib_str = " (%s)" % (', '.join(attribs)) # now construct the rule output string if show_count: tmp_str += "[%2d] " % (count) dir_str = r.direction.upper() if r.forward: dir_str = "FWD" if r.direction == "in" and not r.forward and \ not verbose and not show_count: dir_str = "" comment_str = "" if r.comment != "": comment_str = " # %s" % r.get_comment() tmp_str += "%-26s %-12s%-26s%s%s\n" % (location['dst'], \ " ".join([r.action.upper(), \ dir_str]), \ location['src'], attrib_str, comment_str) # Show the list in the order given if a numbered list, otherwise # split incoming and outgoing rules if show_count: s += tmp_str else: if r.forward: str_rte += tmp_str elif r.direction == "out": str_out += tmp_str else: s += tmp_str count += 1 if s != "" or str_out != "" or str_rte != "": full_str = "\n\n" if show_count: full_str += " " str_to = _("To") str_from = _("From") str_action = _("Action") rules_header_fmt = "%-26s %-12s%s\n" rules_header = rules_header_fmt % (str_to, str_action, str_from) if show_count: rules_header += " " rules_header += rules_header_fmt % \ ("-" * len(str_to), \ "-" * len(str_action), \ "-" * len(str_from)) full_str += rules_header if s != "": full_str += s if s != "" and str_out != "": full_str += _("\n") if str_out != "": full_str += str_out if s != "" and str_rte != "": full_str += _("\n") if str_rte != "": full_str += str_rte s = full_str if verbose: (level, logging_str) = self.get_loglevel() policy_str = _("Default: %(in)s (incoming), " + "%(out)s (outgoing), " + "%(routed)s (routed)") \ % ({'in': self._get_default_policy(), \ 'out': self._get_default_policy("output"), \ 'routed': self._get_default_policy("forward", \ True)}) app_policy_str = self.get_default_application_policy() return _("Status: active\n%(log)s\n%(pol)s\n%(app)s%(status)s") % \ ({'log': logging_str, 'pol': policy_str, \ 'app': app_policy_str, 'status': s}) else: return _("Status: active%s") % (s) def stop_firewall(self): '''Stop the firewall''' if self.dryrun: msg("> " + _("running ufw-init")) else: args = [] args.append(self.files['init']) if self.rootdir is not None and self.datadir is not None: args.append('--rootdir') args.append(self.rootdir) args.append('--datadir') args.append(self.datadir) args.append('force-stop') (rc, out) = cmd(args) if rc != 0: err_msg = _("problem running ufw-init\n%s" % out) raise UFWError(err_msg) def start_firewall(self): '''Start the firewall''' if self.dryrun: msg("> " + _("running ufw-init")) else: args = [] args.append(self.files['init']) if self.rootdir is not None and self.datadir is not None: args.append('--rootdir') args.append(self.rootdir) args.append('--datadir') args.append(self.datadir) args.append('start') (rc, out) = cmd(args) if rc != 0: err_msg = _("problem running ufw-init\n%s" % out) raise UFWError(err_msg) if 'loglevel' not in self.defaults or \ self.defaults['loglevel'] not in list(self.loglevels.keys()): # Add the loglevel if not valid try: self.set_loglevel("low") except Exception: err_msg = _("Could not set LOGLEVEL") raise UFWError(err_msg) else: try: self.update_logging(self.defaults['loglevel']) except Exception: err_msg = _("Could not load logging rules") raise UFWError(err_msg) def _need_reload(self, v6): '''Check if all chains exist''' if self.dryrun: return False # Initialize the capabilities database self.initcaps() prefix = "ufw" exe = self.iptables if v6: prefix = "ufw6" exe = self.ip6tables for chain in [ 'input', 'output', 'forward', 'limit', 'limit-accept' ]: if chain == "limit" or chain == "limit-accept": if v6 and not self.caps['limit']['6']: continue elif not v6 and not self.caps['limit']['4']: continue (rc, out) = cmd([exe, '-n', '-L', prefix + "-user-" + chain]) if rc != 0: debug("_need_reload: forcing reload") return True return False def _reload_user_rules(self): '''Reload firewall rules file''' err_msg = _("problem running") if self.dryrun: msg("> | iptables-restore") if self.use_ipv6(): msg("> | ip6tables-restore") elif self.is_enabled(): # first flush the user logging chains try: for c in self.chains['user']: self._chain_cmd(c, ['-F', c]) self._chain_cmd(c, ['-Z', c]) except Exception: # pragma: no coverage raise UFWError(err_msg) # then restore the system rules (rc, out) = cmd_pipe(['cat', self.files['rules']], \ [self.iptables_restore, '-n']) if rc != 0: raise UFWError(err_msg + " iptables") if self.use_ipv6(): (rc, out) = cmd_pipe(['cat', self.files['rules6']], \ [self.ip6tables_restore, '-n']) if rc != 0: raise UFWError(err_msg + " ip6tables") def _get_rules_from_formatted(self, frule, prefix, suffix): '''Return list of iptables rules appropriate for sending''' snippets = [] # adjust reject and protocol 'all' pat_proto = re.compile(r'-p all ') pat_port = re.compile(r'port ') pat_reject = re.compile(r'-j (REJECT(_log(-all)?)?)') if pat_proto.search(frule): if pat_port.search(frule): if pat_reject.search(frule): snippets.append(pat_proto.sub('-p tcp ', \ pat_reject.sub(r'-j \1 --reject-with tcp-reset', \ frule))) else: snippets.append(pat_proto.sub('-p tcp ', frule)) snippets.append(pat_proto.sub('-p udp ', frule)) else: snippets.append(pat_proto.sub('', frule)) else: snippets.append(frule) # adjust for logging rules pat_log = re.compile(r'(.*)-j ([A-Z]+)_log(-all)?(.*)') pat_logall = re.compile(r'-j [A-Z]+_log-all') pat_chain = re.compile(r'(-A|-D) ([a-zA-Z0-9\-]+)') limit_args = '-m limit --limit 3/min --limit-burst 10' for i, s in enumerate(snippets): if pat_log.search(s): policy = pat_log.sub(r'\2', s).strip() if policy.lower() == "accept": policy = "ALLOW" elif policy.lower() == "limit": policy = "LIMIT" else: policy = "BLOCK" lstr = '%s -j LOG --log-prefix "[UFW %s] "' % (limit_args, \ policy) if not pat_logall.search(s): lstr = '-m conntrack --ctstate NEW ' + lstr snippets[i] = pat_log.sub(r'\1-j \2\4', s) snippets.insert(i, pat_log.sub(r'\1-j ' + prefix + \ '-user-logging-' + suffix, s)) snippets.insert(i, pat_chain.sub(r'\1 ' + prefix + \ '-user-logging-' + suffix, pat_log.sub(r'\1-j RETURN', \ s))) snippets.insert(i, pat_chain.sub(r'\1 ' + prefix + \ '-user-logging-' + suffix, pat_log.sub(r'\1' + lstr, s))) # adjust for limit pat_limit = re.compile(r' -j LIMIT') for i, s in enumerate(snippets): if pat_limit.search(s): tmp1 = pat_limit.sub(' -m conntrack --ctstate NEW -m recent --set', \ s) tmp2 = pat_limit.sub(' -m conntrack --ctstate NEW -m recent' + \ ' --update --seconds 30 --hitcount 6' + \ ' -j ' + prefix + '-user-limit', s) tmp3 = pat_limit.sub(' -j ' + prefix + '-user-limit-accept', s) snippets[i] = tmp3 snippets.insert(i, tmp2) snippets.insert(i, tmp1) return snippets def _get_lists_from_formatted(self, frule, prefix, suffix): '''Return list of iptables rules appropriate for sending as arguments to cmd() ''' snippets = [] str_snippets = self._get_rules_from_formatted(frule, prefix, suffix) # split the string such that the log prefix can contain spaces pat = re.compile(r'(.*) --log-prefix (".* ")(.*)') for i, s in enumerate(str_snippets): snippets.append(pat.sub(r'\1', s).split()) if pat.match(s): snippets[i].append("--log-prefix") snippets[i].append(pat.sub(r'\2', s).replace('"', '')) snippets[i] += pat.sub(r'\3', s).split() return snippets def _read_rules(self): '''Read in rules that were added by ufw''' rfns = [self.files['rules']] if self.use_ipv6(): rfns.append(self.files['rules6']) for f in rfns: try: orig = ufw.util.open_file_read(f) except Exception: err_msg = _("Couldn't open '%s' for reading") % (f) raise UFWError(err_msg) pat_tuple = re.compile(r'^### tuple ###\s*') pat_iface_in = re.compile(r'in_\w+') pat_iface_out = re.compile(r'out_\w+') for orig_line in orig: line = orig_line comment = "" # comment= should always be last, so just strip it out if ' comment=' in orig_line: line, hex = orig_line.split(r' comment=') comment = hex.strip() if pat_tuple.match(line): tupl = pat_tuple.sub('', line) tmp = re.split(r'\s+', tupl.strip()) if len(tmp) < 6 or len(tmp) > 9: wmsg = _("Skipping malformed tuple (bad length): %s") \ % (tupl) warn(wmsg) continue else: # set direction to "in" to support upgrades # from old format, which only had 6 or 8 fields. dtype = "in" interface_in = "" interface_out = "" if len(tmp) == 7 or len(tmp) == 9: wmsg = _("Skipping malformed tuple (iface): %s") \ % (tupl) dtype = tmp[-1].split('_')[0] if '_' in tmp[-1]: if '!' in tmp[-1] and \ pat_iface_in.search(tmp[-1]) and \ pat_iface_out.search(tmp[-1]): # in_eth0!out_eth1 interface_in = \ tmp[-1].split('!')[0].partition('_')[2] interface_out = \ tmp[-1].split('!')[1].partition('_')[2] elif tmp[-1].startswith("in_"): # in_eth0 interface_in = tmp[-1].partition('_')[2] elif tmp[-1].startswith("out_"): # out_eth0 interface_out = tmp[-1].partition('_')[2] else: warn(wmsg) continue try: action = tmp[0] forward = False # route rules use 'route:<action> ...' if ':' in action: forward = True action = action.split(':')[1] if len(tmp) < 8: rule = UFWRule(action, tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], dtype, forward, comment) else: rule = UFWRule(action, tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], dtype, forward, comment) # Removed leading [sd]app_ and unescape spaces pat_space = re.compile('%20') if tmp[6] != "-": rule.dapp = pat_space.sub(' ', tmp[6]) if tmp[7] != "-": rule.sapp = pat_space.sub(' ', tmp[7]) if interface_in != "": rule.set_interface("in", interface_in) if interface_out != "": rule.set_interface("out", interface_out) except UFWError: warn_msg = _("Skipping malformed tuple: %s") % \ (tupl) warn(warn_msg) continue if f == self.files['rules6']: rule.set_v6(True) self.rules6.append(rule) else: rule.set_v6(False) self.rules.append(rule) orig.close() def _write_rules(self, v6=False): '''Write out new rules to file to user chain file''' rules_file = self.files['rules'] if v6: rules_file = self.files['rules6'] # Perform this here so we can present a nice error to the user rather # than a traceback if not os.access(rules_file, os.W_OK): err_msg = _("'%s' is not writable" % (rules_file)) raise UFWError(err_msg) try: fns = ufw.util.open_files(rules_file) except Exception: raise # Initialize the capabilities database self.initcaps() chain_prefix = "ufw" rules = self.rules if v6: chain_prefix = "ufw6" rules = self.rules6 if self.dryrun: fd = sys.stdout.fileno() else: fd = fns['tmp'] # Write header ufw.util.write_to_file(fd, "*filter\n") ufw.util.write_to_file(fd, ":" + chain_prefix + "-user-input - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-user-output - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-user-forward - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-before-logging-input - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-before-logging-output - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-before-logging-forward - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-user-logging-input - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-user-logging-output - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-user-logging-forward - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-after-logging-input - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-after-logging-output - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-after-logging-forward - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-logging-deny - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-logging-allow - [0:0]\n") # Rate limiting is runtime supported if (chain_prefix == "ufw" and self.caps['limit']['4']) or \ (chain_prefix == "ufw6" and self.caps['limit']['6']): ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-user-limit - [0:0]\n") ufw.util.write_to_file(fd, ":" + chain_prefix + \ "-user-limit-accept - [0:0]\n") ufw.util.write_to_file(fd, "### RULES ###\n") # Write rules for r in rules: action = r.action # route rules use 'route:<action> ...' if r.forward: action = "route:" + r.action if r.logtype != "": action += "_" + r.logtype ifaces = "" if r.interface_in == "" and r.interface_out == "": ifaces = r.direction elif r.interface_in != "" and r.interface_out != "": ifaces = "in_%s!out_%s" % (r.interface_in, r.interface_out) else: if r.interface_in != "": ifaces += "%s_%s" % (r.direction, r.interface_in) else: ifaces += "%s_%s" % (r.direction, r.interface_out) if r.dapp == "" and r.sapp == "": tstr = "\n### tuple ### %s %s %s %s %s %s %s" % \ (action, r.protocol, r.dport, r.dst, r.sport, r.src, ifaces) if r.comment != '': tstr += " comment=%s" % r.comment ufw.util.write_to_file(fd, tstr + "\n") else: pat_space = re.compile(' ') dapp = "-" if r.dapp: dapp = pat_space.sub('%20', r.dapp) sapp = "-" if r.sapp: sapp = pat_space.sub('%20', r.sapp) tstr = "\n### tuple ### %s %s %s %s %s %s %s %s %s" % \ (action, r.protocol, r.dport, r.dst, r.sport, r.src, \ dapp, sapp, ifaces) if r.comment != '': tstr += " comment=%s" % r.comment ufw.util.write_to_file(fd, tstr + "\n") chain_suffix = "input" if r.forward: chain_suffix = "forward" elif r.direction == "out": chain_suffix = "output" chain = "%s-user-%s" % (chain_prefix, chain_suffix) rule_str = "-A %s %s\n" % (chain, r.format_rule()) for s in self._get_rules_from_formatted(rule_str, chain_prefix, \ chain_suffix): ufw.util.write_to_file(fd, s) # Write footer ufw.util.write_to_file(fd, "\n### END RULES ###\n") # Add logging rules, skipping any delete ('-D') rules ufw.util.write_to_file(fd, "\n### LOGGING ###\n") try: lrules_t = self._get_logging_rules(self.defaults['loglevel']) except Exception: raise for c, r, q in lrules_t: if len(r) > 0 and r[0] == '-D': continue if c.startswith(chain_prefix + "-"): ufw.util.write_to_file(fd, " ".join(r).replace('[', '"[').replace('] ', '] "') + \ "\n") ufw.util.write_to_file(fd, "### END LOGGING ###\n") # Rate limiting is runtime supported if (chain_prefix == "ufw" and self.caps['limit']['4']) or \ (chain_prefix == "ufw6" and self.caps['limit']['6']): ufw.util.write_to_file(fd, "\n### RATE LIMITING ###\n") if self.defaults['loglevel'] != "off": ufw.util.write_to_file(fd, "-A " + \ chain_prefix + "-user-limit " + \ " ".join(self.ufw_user_limit_log) + \ " \"" + self.ufw_user_limit_log_text + " \"\n") ufw.util.write_to_file(fd, "-A " + chain_prefix + \ "-user-limit -j REJECT\n") ufw.util.write_to_file(fd, "-A " + chain_prefix + \ "-user-limit-accept -j ACCEPT\n") ufw.util.write_to_file(fd, "### END RATE LIMITING ###\n") ufw.util.write_to_file(fd, "COMMIT\n") try: if self.dryrun: ufw.util.close_files(fns, False) else: ufw.util.close_files(fns) except Exception: raise def set_rule(self, rule, allow_reload=True): '''Updates firewall with rule by: * appending the rule to the chain if new rule and firewall enabled * deleting the rule from the chain if found and firewall enabled * inserting the rule if possible and firewall enabled * updating user rules file * reloading the user rules file if rule is modified ''' # Initialize the capabilities database self.initcaps() rstr = "" if rule.v6: if not self.use_ipv6(): err_msg = _("Adding IPv6 rule failed: IPv6 not enabled") raise UFWError(err_msg) if rule.action == 'limit' and not self.caps['limit']['6']: # Rate limiting is runtime supported return _("Skipping unsupported IPv6 '%s' rule") % (rule.action) else: if rule.action == 'limit' and not self.caps['limit']['4']: # Rate limiting is runtime supported return _("Skipping unsupported IPv4 '%s' rule") % (rule.action) if rule.multi and rule.protocol != "udp" and rule.protocol != "tcp": err_msg = _("Must specify 'tcp' or 'udp' with multiple ports") raise UFWError(err_msg) newrules = [] found = False modified = False rules = self.rules position = rule.position if rule.v6: if self.iptables_version < "1.4" and (rule.dapp != "" or \ rule.sapp != ""): return _("Skipping IPv6 application rule. Need at least iptables 1.4") rules = self.rules6 # bail if we have a bad position if position < 0 or position > len(rules): err_msg = _("Invalid position '%d'") % (position) raise UFWError(err_msg) if position > 0 and rule.remove: err_msg = _("Cannot specify insert and delete") raise UFWError(err_msg) if position > len(rules): err_msg = _("Cannot insert rule at position '%d'") % position raise UFWError(err_msg) # First construct the new rules list try: rule.normalize() except Exception: raise count = 1 inserted = False matches = 0 last = ('', '', '', '') for r in rules: try: r.normalize() except Exception: raise current = (r.dst, r.src, r.dapp, r.sapp) if count == position: # insert the rule if: # 1. the last rule was not an application rule # 2. the current rule is not an application rule # 3. the last application rule is different than the current # while the new rule is different than the current one if (last[2] == '' and last[3] == '' and count > 1) or \ (current[2] == '' and current[3] == '') or \ last != current: inserted = True newrules.append(rule.dup_rule()) last = ('', '', '', '') else: position += 1 last = current count += 1 ret = UFWRule.match(r, rule) if ret < 1: matches += 1 if ret == 0 and not found and not inserted: # If find the rule, add it if it's not to be removed, otherwise # skip it. found = True if not rule.remove: newrules.append(rule.dup_rule()) elif ret == -2 and rule.remove and rule.comment == '': # Allow removing a rule if the comment is empty found = True elif ret < 0 and not rule.remove and not inserted: # If only the action is different, replace the rule if it's not # to be removed. found = True modified = True newrules.append(rule.dup_rule()) else: newrules.append(r) if inserted: if matches > 0: rstr = _("Skipping inserting existing rule") if rule.v6: rstr += " (v6)" return rstr else: # Add rule to the end if it was not already added. if not found and not rule.remove: newrules.append(rule.dup_rule()) # Don't process non-existing or unchanged pre-exisiting rules if not found and rule.remove and not self.dryrun: rstr = _("Could not delete non-existent rule") if rule.v6: rstr += " (v6)" return rstr elif found and not rule.remove and not modified: rstr = _("Skipping adding existing rule") if rule.v6: rstr += " (v6)" return rstr if rule.v6: self.rules6 = newrules else: self.rules = newrules # Update the user rules file try: self._write_rules(rule.v6) except UFWError: raise except Exception: err_msg = _("Couldn't update rules file") UFWError(err_msg) # We wrote out the rules, so set reasonable string. We will change # this below when operating on the live firewall. rstr = _("Rules updated") if rule.v6: rstr = _("Rules updated (v6)") # Operate on the chains if self.is_enabled() and not self.dryrun: flag = "" if modified or self._need_reload(rule.v6) or inserted: rstr = "" if inserted: rstr += _("Rule inserted") else: rstr += _("Rule updated") if rule.v6: rstr += " (v6)" if allow_reload: # Reload the chain try: self._reload_user_rules() except Exception: raise else: rstr += _(" (skipped reloading firewall)") elif found and rule.remove: flag = '-D' rstr = _("Rule deleted") elif not found and not modified and not rule.remove: flag = '-A' rstr = _("Rule added") if flag != "": exe = self.iptables chain_prefix = "ufw" if rule.v6: exe = self.ip6tables chain_prefix = "ufw6" rstr += " (v6)" chain_suffix = "input" if rule.forward: chain_suffix = "forward" elif rule.direction == "out": chain_suffix = "output" chain = "%s-user-%s" % (chain_prefix, chain_suffix) # Is the firewall running? err_msg = _("Could not update running firewall") (rc, out) = cmd([exe, '-L', chain, '-n']) if rc != 0: raise UFWError(err_msg) rule_str = "%s %s %s" % (flag, chain, rule.format_rule()) pat_log = re.compile(r'(-A +)(ufw6?-user-[a-z\-]+)(.*)') for s in self._get_lists_from_formatted(rule_str, \ chain_prefix, \ chain_suffix): (rc, out) = cmd([exe] + s) if rc != 0: msg(out, sys.stderr) UFWError(err_msg) # delete any lingering RETURN rules (needed for upgrades) if flag == "-A" and pat_log.search(" ".join(s)): c = pat_log.sub(r'\2', " ".join(s)) (rc, out) = cmd([exe, '-D', c, '-j', 'RETURN']) if rc != 0: debug("FAILOK: -D %s -j RETURN" % (c)) return rstr def get_app_rules_from_system(self, template, v6): '''Return a list of UFWRules from the system based on template rule''' rules = [] app_rules = [] if v6: rules = self.rules6 else: rules = self.rules norm = template.dup_rule() norm.set_v6(v6) norm.normalize() tupl = norm.get_app_tuple() for r in rules: tmp = r.dup_rule() tmp.normalize() tmp_tuple = tmp.get_app_tuple() if tmp_tuple == tupl: app_rules.append(tmp) return app_rules def _chain_cmd(self, chain, args, fail_ok=False): '''Perform command on chain''' exe = self.iptables if chain.startswith("ufw6"): exe = self.ip6tables (rc, out) = cmd([exe] + args) if rc != 0: err_msg = _("Could not perform '%s'" % (args)) if fail_ok: debug("FAILOK: " + err_msg) else: raise UFWError(err_msg) def update_logging(self, level): '''Update loglevel of running firewall''' if self.dryrun: return # Initialize the capabilities database self.initcaps() rules_t = [] try: rules_t = self._get_logging_rules(level) except Exception: raise # Update the user rules file try: self._write_rules(v6=False) self._write_rules(v6=True) except UFWError: raise except Exception: err_msg = _("Couldn't update rules file for logging") UFWError(err_msg) # Don't update the running firewall if not enabled if not self.is_enabled(): return # make sure all the chains are here, it's redundant but helps make # sure the chains are in a consistent state err_msg = _("Could not update running firewall") for c in self.chains['before'] + self.chains['user'] + \ self.chains['after'] + self.chains['misc']: try: self._chain_cmd(c, ['-L', c, '-n']) except Exception: raise UFWError(err_msg) # Flush all the logging chains except 'user' try: for c in self.chains['before'] + self.chains['after'] + \ self.chains['misc']: self._chain_cmd(c, ['-F', c]) self._chain_cmd(c, ['-Z', c]) except Exception: raise UFWError(err_msg) # Add logging rules to running firewall for c, r, q in rules_t: fail_ok = False if len(r) > 0 and r[0] == '-D': fail_ok = True try: if q == 'delete_first' and len(r) > 1: self._chain_cmd(c, ['-D'] + r[1:], fail_ok=True) self._chain_cmd(c, r, fail_ok) except Exception: raise UFWError(err_msg) # Rate limiting is runtime supported # Always delete these and re-add them so that we don't have extras for chain in ['ufw-user-limit', 'ufw6-user-limit']: if (self.caps['limit']['4'] and chain == 'ufw-user-limit') or \ (self.caps['limit']['6'] and chain == 'ufw6-user-limit'): self._chain_cmd(chain, ['-D', chain] + \ self.ufw_user_limit_log + \ [self.ufw_user_limit_log_text + " "], \ fail_ok=True) if self.defaults["loglevel"] != "off": self._chain_cmd(chain, ['-I', chain] + \ self.ufw_user_limit_log + \ [self.ufw_user_limit_log_text + " "], \ fail_ok=True) def _get_logging_rules(self, level): '''Get rules for specified logging level''' rules_t = [] if level not in list(self.loglevels.keys()): err_msg = _("Invalid log level '%s'") % (level) raise UFWError(err_msg) if level == "off": # when off, insert a RETURN rule at the top of user rules, thus # preserving the rules for c in self.chains['user']: rules_t.append([c, ['-I', c, '-j', 'RETURN'], 'delete_first']) return rules_t else: # when on, remove the RETURN rule at the top of user rules, thus # honoring the log rules for c in self.chains['user']: rules_t.append([c, ['-D', c, '-j', 'RETURN'], '']) limit_args = ['-m', 'limit', '--limit', '3/min', '--limit-burst', '10'] # log levels of low and higher log blocked packets if self.loglevels[level] >= self.loglevels["low"]: # Setup the policy violation logging chains largs = [] # log levels under high use limit if self.loglevels[level] < self.loglevels["high"]: largs = limit_args for c in self.chains['after']: for t in ['input', 'output', 'forward']: if c.endswith(t): if self._get_default_policy(t) == "reject" or \ self._get_default_policy(t) == "deny": prefix = "[UFW BLOCK] " rules_t.append([c, ['-A', c, '-j', 'LOG', \ '--log-prefix', prefix] + largs, '']) elif self.loglevels[level] >= self.loglevels["medium"]: prefix = "[UFW ALLOW] " rules_t.append([c, ['-A', c, '-j', 'LOG', \ '--log-prefix', prefix] + \ largs, '']) # Setup the miscellaneous logging chains largs = [] # log levels under high use limit if self.loglevels[level] < self.loglevels["high"]: largs = limit_args for c in self.chains['misc']: if c.endswith("allow"): prefix = "[UFW ALLOW] " elif c.endswith("deny"): prefix = "[UFW BLOCK] " if self.loglevels[level] < self.loglevels["medium"]: # only log INVALID in medium and higher rules_t.append([c, ['-I', c, '-m', 'conntrack', \ '--ctstate', 'INVALID', \ '-j', 'RETURN'] + largs, '']) else: rules_t.append([c, ['-A', c, '-m', 'conntrack', \ '--ctstate', 'INVALID', \ '-j', 'LOG', \ '--log-prefix', \ "[UFW AUDIT INVALID] "] + \ largs, '']) rules_t.append([c, ['-A', c, '-j', 'LOG', \ '--log-prefix', prefix] + largs, '']) # Setup the audit logging chains if self.loglevels[level] >= self.loglevels["medium"]: # loglevel full logs all packets without limit largs = [] # loglevel high logs all packets with limit if self.loglevels[level] < self.loglevels["full"]: largs = limit_args # loglevel medium logs all new packets with limit if self.loglevels[level] < self.loglevels["high"]: largs = ['-m', 'conntrack', '--ctstate', 'NEW'] + limit_args prefix = "[UFW AUDIT] " for c in self.chains['before']: rules_t.append([c, ['-I', c, '-j', 'LOG', \ '--log-prefix', prefix] + largs, '']) return rules_t def reset(self): '''Reset the firewall''' res = "" share_dir = _findpath(ufw.common.share_dir, self.rootdir) # First make sure we have all the original files allfiles = [] for i in self.files: if not self.files[i].endswith('.rules'): continue allfiles.append(self.files[i]) fn = os.path.join(share_dir, "iptables", \ os.path.basename(self.files[i])) if not os.path.isfile(fn): err_msg = _("Could not find '%s'. Aborting") % (fn) raise UFWError(err_msg) ext = time.strftime("%Y%m%d_%H%M%S") # This implementation will intentionally traceback if someone tries to # do something to take advantage of the race conditions here. # Don't do anything if the files already exist for i in allfiles: fn = "%s.%s" % (i, ext) if os.path.exists(fn): err_msg = _("'%s' already exists. Aborting") % (fn) raise UFWError(err_msg) # Move the old to the new for i in allfiles: fn = "%s.%s" % (i, ext) res += _("Backing up '%(old)s' to '%(new)s'\n") % (\ {'old': os.path.basename(i), 'new': fn}) os.rename(i, fn) # Copy files into place for i in allfiles: old = "%s.%s" % (i, ext) shutil.copy(os.path.join(share_dir, "iptables", \ os.path.basename(i)), \ os.path.dirname(i)) shutil.copymode(old, i) try: statinfo = os.stat(i) mode = statinfo[stat.ST_MODE] except Exception: warn_msg = _("Couldn't stat '%s'") % (i) warn(warn_msg) continue if mode & stat.S_IWOTH: res += _("WARN: '%s' is world writable") % (i) elif mode & stat.S_IROTH: res += _("WARN: '%s' is world readable") % (i) return res