fw.py 12.1 KB
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# Copyright 2014 Budapest University of Technology and Economics (BME IK)
#
# This file is part of CIRCLE Cloud.
#
# CIRCLE 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 3 of the License, or (at your option)
# any later version.
#
# CIRCLE 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 CIRCLE.  If not, see <http://www.gnu.org/licenses/>.

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import re
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import logging
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from collections import OrderedDict
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from netaddr import IPAddress, AddrFormatError
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from datetime import timedelta
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from itertools import product

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from .models import (Host, Rule, Vlan, Domain, Record, BlacklistItem,
                     SwitchPort)
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from .iptables import IptRule, IptChain
import django.conf
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from django.db.models import Q
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from django.template import loader, Context
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from django.utils import timezone
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settings = django.conf.settings.FIREWALL_SETTINGS
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logger = logging.getLogger(__name__)
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class BuildFirewall:
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    def __init__(self):
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        self.chains = OrderedDict()
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    def add_rules(self, *args, **kwargs):
        for chain_name, ipt_rule in kwargs.items():
            if chain_name not in self.chains:
                self.create_chain(chain_name)
            self.chains[chain_name].add(ipt_rule)
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    def create_chain(self, chain_name):
        self.chains[chain_name] = IptChain(name=chain_name)
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    def build_ipt_nat(self):
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        # portforward
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        for rule in Rule.objects.filter(
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                action__in=['accept', 'drop'],
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                nat=True, direction='in').select_related('host'):
            self.add_rules(PREROUTING=IptRule(
                priority=1000,
                dst=(rule.get_external_ipv4(), None),
                proto=rule.proto,
                dport=rule.get_external_port('ipv4'),
                extra='-j DNAT --to-destination %s:%s' % (rule.host.ipv4,
                                                          rule.dport)))

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        # SNAT rules for machines with public IPv4
        for host in Host.objects.exclude(external_ipv4=None).select_related(
                'vlan').prefetch_related('vlan__snat_to'):
            for vl_out in host.vlan.snat_to.all():
                self.add_rules(POSTROUTING=IptRule(
                    priority=1500, src=(host.ipv4, None),
                    extra='-o %s -j SNAT --to-source %s' % (
                        vl_out.name, host.external_ipv4)))

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        # default outbound NAT rules for VLANs
        for vl_in in Vlan.objects.exclude(
                snat_ip=None).prefetch_related('snat_to'):
            for vl_out in vl_in.snat_to.all():
                self.add_rules(POSTROUTING=IptRule(
                    priority=1000,
                    src=(vl_in.network4, None),
                    extra='-o %s -j SNAT --to-source %s' % (
                        vl_out.name, vl_in.snat_ip)))
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    def ipt_filter_firewall(self):
        """Build firewall's own rules."""

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        rules = Rule.objects.filter(action__in=['accept', 'drop'])
        for rule in rules.exclude(firewall=None).select_related(
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                'foreign_network').prefetch_related('foreign_network__vlans'):
            self.add_rules(**rule.get_ipt_rules())
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    def ipt_filter_host_rules(self):
        """Build hosts' rules."""

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        # host rules
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        rules = Rule.objects.filter(action__in=['accept', 'drop'])
        for rule in rules.exclude(host=None).select_related(
                'foreign_network', 'host', 'host__vlan').prefetch_related(
                'foreign_network__vlans'):
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            self.add_rules(**rule.get_ipt_rules(rule.host))
        # group rules
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        for rule in rules.exclude(hostgroup=None).select_related(
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                'hostgroup', 'foreign_network').prefetch_related(
                'hostgroup__host_set__vlan', 'foreign_network__vlans'):
            for host in rule.hostgroup.host_set.all():
                self.add_rules(**rule.get_ipt_rules(host))
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    def ipt_filter_vlan_rules(self):
        """Enable communication between VLANs."""

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        rules = Rule.objects.filter(action__in=['accept', 'drop'])
        for rule in rules.exclude(vlan=None).select_related(
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                'vlan', 'foreign_network').prefetch_related(
                'foreign_network__vlans'):
            self.add_rules(**rule.get_ipt_rules())
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    def ipt_filter_vlan_drop(self):
        """Close intra-VLAN chains."""

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        for chain in self.chains.values():
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            close_chain_rule = IptRule(priority=1, action='LOG_DROP')
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            chain.add(close_chain_rule)
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    def ipt_filter_vlan_jump(self):
        """Create intra-VLAN jump rules."""

        vlans = Vlan.objects.all().values_list('name', flat=True)
        for vl_in, vl_out in product(vlans, repeat=2):
            name = '%s_%s' % (vl_in, vl_out)
            try:
                chain = self.chains[name]
            except KeyError:
                pass
            else:
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                jump_rule = IptRule(priority=65535, action=chain.name,
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                                    extra='-i %s -o %s' % (vl_in, vl_out))
                self.add_rules(FORWARD=jump_rule)

    def build_ipt(self):
        """Build rules."""

        self.ipt_filter_firewall()
        self.ipt_filter_host_rules()
        self.ipt_filter_vlan_rules()
        self.ipt_filter_vlan_jump()
        self.ipt_filter_vlan_drop()
        self.build_ipt_nat()

        context = {
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            'filter': lambda: (chain for name, chain in self.chains.iteritems()
                               if chain.name not in IptChain.nat_chains),
            'nat': lambda: (chain for name, chain in self.chains.iteritems()
                            if chain.name in IptChain.nat_chains)}
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        template = loader.get_template('firewall/iptables.conf')
        context['proto'] = 'ipv4'
        ipv4 = unicode(template.render(Context(context)))
        context['proto'] = 'ipv6'
        ipv6 = unicode(template.render(Context(context)))
        return (ipv4, ipv6)
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def ipset():
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    week = timezone.now() - timedelta(days=2)
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    filter_ban = (Q(type='tempban', modified_at__gte=week) |
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                  Q(type='permban'))
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    return BlacklistItem.objects.filter(filter_ban).values('ipv4', 'reason')
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def ipv6_to_octal(ipv6):
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    ipv6 = IPAddress(ipv6, version=6)
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    octets = []
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    for part in ipv6.words:
        # Pad hex part to 4 digits.
        part = '%04x' % part
        octets.append(int(part[:2], 16))
        octets.append(int(part[2:], 16))
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    return "".join(r"\%03o" % x for x in octets)
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# =fqdn:ip:ttl          A, PTR
# &fqdn:ip:x:ttl        NS
# ZfqdnSOA
# +fqdn:ip:ttl          A
# ^                     PTR
# C                     CNAME
# :                     generic
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# 'fqdn:s:ttl           TXT
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def generate_ptr_records():
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    DNS = []

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    for host in Host.objects.order_by('vlan').all():
        template = host.vlan.reverse_domain
        i = host.get_external_ipv4().words
        reverse = (host.reverse if host.reverse not in [None, '']
                   else host.get_fqdn())
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        # ipv4
        if host.ipv4:
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            fqdn = template % {'a': i[0], 'b': i[1], 'c': i[2], 'd': i[3]}
            DNS.append("^%s:%s:%s" % (fqdn, reverse, settings['dns_ttl']))
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        # ipv6
        if host.ipv6:
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            DNS.append("^%s:%s:%s" % (host.ipv6.reverse_dns.rstrip('.'),
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                                      reverse, settings['dns_ttl']))
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    return DNS
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def txt_to_octal(txt):
    return '\\' + '\\'.join(['%03o' % ord(x) for x in txt])


def generate_records():
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    types = {'A': '+%(fqdn)s:%(address)s:%(ttl)s',
             'AAAA': ':%(fqdn)s:28:%(octal)s:%(ttl)s',
             'NS': '&%(fqdn)s::%(address)s:%(ttl)s',
             'CNAME': 'C%(fqdn)s:%(address)s:%(ttl)s',
             'MX': '@%(fqdn)s::%(address)s:%(dist)s:%(ttl)s',
             'PTR': '^%(fqdn)s:%(address)s:%(ttl)s',
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             'TXT': "'%(fqdn)s:%(octal)s:%(ttl)s"}
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    retval = []

    for r in Record.objects.all():
        params = {'fqdn': r.fqdn, 'address': r.address, 'ttl': r.ttl}
        if r.type == 'MX':
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            params['dist'], params['address'] = r.address.split(':', 2)
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        if r.type == 'AAAA':
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            try:
                params['octal'] = ipv6_to_octal(r.address)
            except AddrFormatError:
                logger.error('Invalid ipv6 address: %s, record: %s',
                             r.address, r)
                continue
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        if r.type == 'TXT':
            params['octal'] = txt_to_octal(r.address)
        retval.append(types[r.type] % params)
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    return retval
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def dns():
    DNS = []

    # host PTR record
    DNS += generate_ptr_records()

    # domain SOA record
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    for domain in Domain.objects.all():
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        DNS.append("Z%s:%s:support.ik.bme.hu::::::%s" %
                   (domain.name, settings['dns_hostname'],
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                    settings['dns_ttl']))
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    # records
    DNS += generate_records()
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    return DNS


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class UniqueHostname(object):
    """Append vlan id if hostname already exists."""
    def __init__(self):
        self.used_hostnames = set()

    def get(self, hostname, vlan_id):
        if hostname in self.used_hostnames:
            hostname = "%s-%s" % (hostname, vlan_id)
        self.used_hostnames.add(hostname)
        return hostname


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def dhcp():
    regex = re.compile(r'^([0-9]+)\.([0-9]+)\.[0-9]+\.[0-9]+\s+'
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                       r'([0-9]+)\.([0-9]+)\.[0-9]+\.[0-9]+$')
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    config = []
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    VLAN_TEMPLATE = '''
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    # %(name)s - %(interface)s
    subnet %(net)s netmask %(netmask)s {
      %(extra)s;
      option domain-name "%(domain)s";
      option routers %(router)s;
      option domain-name-servers %(dnsserver)s;
      option ntp-servers %(ntp)s;
      next-server %(tftp)s;
      authoritative;
      filename \"pxelinux.0\";
      allow bootp; allow booting;
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    }'''

    HOST_TEMPLATE = '''
    host %(hostname)s {
        hardware ethernet %(mac)s;
        fixed-address %(ipv4)s;
    }'''

    unique_hostnames = UniqueHostname()

    for vlan in Vlan.objects.exclude(
            dhcp_pool=None).select_related(
            'domain').prefetch_related('host_set'):
        m = regex.search(vlan.dhcp_pool)
        if(m or vlan.dhcp_pool == "manual"):
            config.append(VLAN_TEMPLATE % {
                'net': str(vlan.network4.network),
                'netmask': str(vlan.network4.netmask),
                'domain': vlan.domain,
                'router': vlan.network4.ip,
                'ntp': vlan.network4.ip,
                'dnsserver': settings['rdns_ip'],
                'extra': ("range %s" % vlan.dhcp_pool
                          if m else "deny unknown-clients"),
                'interface': vlan.name,
                'name': vlan.name,
                'tftp': vlan.network4.ip})

            for host in vlan.host_set.all():
                config.append(HOST_TEMPLATE % {
                    'hostname': unique_hostnames.get(host.hostname, vlan.vid),
                    'mac': host.mac,
                    'ipv4': host.ipv4,
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                })

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    return config
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def vlan():
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    obj = Vlan.objects.filter(managed=True).values(
        'vid', 'name', 'network4', 'network6')
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    retval = {x['name']: {'tag': x['vid'],
                          'type': 'internal',
                          'interfaces': [x['name']],
                          'addresses': [str(x['network4']),
                                        str(x['network6'])]}
              for x in obj}
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    for p in SwitchPort.objects.all():
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        eth_count = p.ethernet_devices.count()
        if eth_count > 1:
            name = 'bond%d' % p.id
        elif eth_count == 1:
            name = p.ethernet_devices.get().name
        else:  # 0
            continue
        tag = p.untagged_vlan.vid
        retval[name] = {'tag': tag}
        if p.tagged_vlans is not None:
            trunk = list(p.tagged_vlans.vlans.values_list('vid', flat=True))
            retval[name]['trunks'] = sorted(trunk)
        retval[name]['interfaces'] = list(
            p.ethernet_devices.values_list('name', flat=True))
    return retval