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nftables.py
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nftables.py
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# -*- coding: utf-8 -*-
#
# Copyright (C) 2018 Red Hat, Inc.
#
# Authors:
# Eric Garver <e@erig.me>
#
# 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/>.
#
from __future__ import absolute_import
import copy
import json
from firewall.core.logger import log
from firewall.functions import check_mac, getPortRange, normalizeIP6, \
check_single_address, check_address
from firewall.errors import FirewallError, UNKNOWN_ERROR, INVALID_RULE, \
INVALID_ICMPTYPE, INVALID_TYPE, INVALID_ENTRY, \
INVALID_PORT
from firewall.core.rich import Rich_Accept, Rich_Reject, Rich_Drop, Rich_Mark, \
Rich_Masquerade, Rich_ForwardPort, Rich_IcmpBlock
from nftables.nftables import Nftables
TABLE_NAME = "firewalld"
TABLE_NAME_POLICY = TABLE_NAME + "_" + "policy_drop"
POLICY_CHAIN_PREFIX = "policy_"
# Map iptables (table, chain) to hooks and priorities.
# These are well defined by NF_IP_PRI_* defines in netfilter.
#
# This is analogous to ipXtables.BUILT_IN_CHAINS, but we omit the chains that
# are only used for direct rules.
#
# Note: All hooks use their standard position + NFT_HOOK_OFFSET. This means
# iptables will have DROP precedence. It also means that even if iptables
# ACCEPTs a packet it may still be dropped later by firewalld's rules.
#
NFT_HOOK_OFFSET = 10
IPTABLES_TO_NFT_HOOK = {
#"security": {
# "INPUT": ("input", 50 + NFT_HOOK_OFFSET),
# "OUTPUT": ("output", 50 + NFT_HOOK_OFFSET),
# "FORWARD": ("forward", 50 + NFT_HOOK_OFFSET),
#},
"raw": {
"PREROUTING": ("prerouting", -300 + NFT_HOOK_OFFSET),
# "OUTPUT": ("output", -300 + NFT_HOOK_OFFSET),
},
"mangle": {
"PREROUTING": ("prerouting", -150 + NFT_HOOK_OFFSET),
# "POSTROUTING": ("postrouting", -150 + NFT_HOOK_OFFSET),
# "INPUT": ("input", -150 + NFT_HOOK_OFFSET),
# "OUTPUT": ("output", -150 + NFT_HOOK_OFFSET),
# "FORWARD": ("forward", -150 + NFT_HOOK_OFFSET),
},
"nat": {
"PREROUTING": ("prerouting", -100 + NFT_HOOK_OFFSET),
"POSTROUTING": ("postrouting", 100 + NFT_HOOK_OFFSET),
# "INPUT": ("input", 100 + NFT_HOOK_OFFSET),
# "OUTPUT": ("output", -100 + NFT_HOOK_OFFSET),
},
"filter": {
"INPUT": ("input", 0 + NFT_HOOK_OFFSET),
"FORWARD": ("forward", 0 + NFT_HOOK_OFFSET),
"OUTPUT": ("output", 0 + NFT_HOOK_OFFSET),
},
}
def _icmp_types_fragments(protocol, type, code=None):
fragments = [{"match": {"left": {"payload": {"protocol": protocol, "field": "type"}},
"op": "==",
"right": type}}]
if code:
fragments.append({"match": {"left": {"payload": {"protocol": protocol, "field": "code"}},
"op": "==",
"right": code}})
return fragments
# Most ICMP types are provided by nft, but for the codes we have to use numeric
# values.
#
ICMP_TYPES_FRAGMENTS = {
"ipv4": {
"communication-prohibited": _icmp_types_fragments("icmp", "destination-unreachable", 13),
"destination-unreachable": _icmp_types_fragments("icmp", "destination-unreachable"),
"echo-reply": _icmp_types_fragments("icmp", "echo-reply"),
"echo-request": _icmp_types_fragments("icmp", "echo-request"),
"fragmentation-needed": _icmp_types_fragments("icmp", "destination-unreachable", 4),
"host-precedence-violation": _icmp_types_fragments("icmp", "destination-unreachable", 14),
"host-prohibited": _icmp_types_fragments("icmp", "destination-unreachable", 10),
"host-redirect": _icmp_types_fragments("icmp", "redirect", 1),
"host-unknown": _icmp_types_fragments("icmp", "destination-unreachable", 7),
"host-unreachable": _icmp_types_fragments("icmp", "destination-unreachable", 1),
"ip-header-bad": _icmp_types_fragments("icmp", "parameter-problem", 1),
"network-prohibited": _icmp_types_fragments("icmp", "destination-unreachable", 8),
"network-redirect": _icmp_types_fragments("icmp", "redirect", 0),
"network-unknown": _icmp_types_fragments("icmp", "destination-unreachable", 6),
"network-unreachable": _icmp_types_fragments("icmp", "destination-unreachable", 0),
"parameter-problem": _icmp_types_fragments("icmp", "parameter-problem"),
"port-unreachable": _icmp_types_fragments("icmp", "destination-unreachable", 3),
"precedence-cutoff": _icmp_types_fragments("icmp", "destination-unreachable", 15),
"protocol-unreachable": _icmp_types_fragments("icmp", "destination-unreachable", 2),
"redirect": _icmp_types_fragments("icmp", "redirect"),
"required-option-missing": _icmp_types_fragments("icmp", "parameter-problem", 1),
"router-advertisement": _icmp_types_fragments("icmp", "router-advertisement"),
"router-solicitation": _icmp_types_fragments("icmp", "router-solicitation"),
"source-quench": _icmp_types_fragments("icmp", "source-quench"),
"source-route-failed": _icmp_types_fragments("icmp", "destination-unreachable", 5),
"time-exceeded": _icmp_types_fragments("icmp", "time-exceeded"),
"timestamp-reply": _icmp_types_fragments("icmp", "timestamp-reply"),
"timestamp-request": _icmp_types_fragments("icmp", "timestamp-request"),
"tos-host-redirect": _icmp_types_fragments("icmp", "redirect", 3),
"tos-host-unreachable": _icmp_types_fragments("icmp", "destination-unreachable", 12),
"tos-network-redirect": _icmp_types_fragments("icmp", "redirect", 2),
"tos-network-unreachable": _icmp_types_fragments("icmp", "destination-unreachable", 11),
"ttl-zero-during-reassembly": _icmp_types_fragments("icmp", "time-exceeded", 1),
"ttl-zero-during-transit": _icmp_types_fragments("icmp", "time-exceeded", 0),
},
"ipv6": {
"address-unreachable": _icmp_types_fragments("icmpv6", "destination-unreachable", 3),
"bad-header": _icmp_types_fragments("icmpv6", "parameter-problem", 0),
"beyond-scope": _icmp_types_fragments("icmpv6", "destination-unreachable", 2),
"communication-prohibited": _icmp_types_fragments("icmpv6", "destination-unreachable", 1),
"destination-unreachable": _icmp_types_fragments("icmpv6", "destination-unreachable"),
"echo-reply": _icmp_types_fragments("icmpv6", "echo-reply"),
"echo-request": _icmp_types_fragments("icmpv6", "echo-request"),
"failed-policy": _icmp_types_fragments("icmpv6", "destination-unreachable", 5),
"neighbour-advertisement": _icmp_types_fragments("icmpv6", "nd-neighbor-advert"),
"neighbour-solicitation": _icmp_types_fragments("icmpv6", "nd-neighbor-solicit"),
"no-route": _icmp_types_fragments("icmpv6", "destination-unreachable", 0),
"packet-too-big": _icmp_types_fragments("icmpv6", "packet-too-big"),
"parameter-problem": _icmp_types_fragments("icmpv6", "parameter-problem"),
"port-unreachable": _icmp_types_fragments("icmpv6", "destination-unreachable", 4),
"redirect": _icmp_types_fragments("icmpv6", "nd-redirect"),
"reject-route": _icmp_types_fragments("icmpv6", "destination-unreachable", 6),
"router-advertisement": _icmp_types_fragments("icmpv6", "nd-router-advert"),
"router-solicitation": _icmp_types_fragments("icmpv6", "nd-router-solicit"),
"time-exceeded": _icmp_types_fragments("icmpv6", "time-exceeded"),
"ttl-zero-during-reassembly": _icmp_types_fragments("icmpv6", "time-exceeded", 1),
"ttl-zero-during-transit": _icmp_types_fragments("icmpv6", "time-exceeded", 0),
"unknown-header-type": _icmp_types_fragments("icmpv6", "parameter-problem", 1),
"unknown-option": _icmp_types_fragments("icmpv6", "parameter-problem", 2),
}
}
class nftables(object):
name = "nftables"
policies_supported = True
def __init__(self, fw):
self._fw = fw
self.restore_command_exists = True
self.available_tables = []
self.rule_to_handle = {}
self.rule_ref_count = {}
self.rich_rule_priority_counts = {}
self.zone_source_index_cache = {}
self.created_tables = {"inet": [], "ip": [], "ip6": []}
self.nftables = Nftables()
self.nftables.set_echo_output(True)
self.nftables.set_handle_output(True)
def _run_replace_zone_source(self, rule, zone_source_index_cache):
for verb in ["add", "insert", "delete"]:
if verb in rule:
break
if "%%ZONE_SOURCE%%" in rule[verb]["rule"]:
zone_source = (rule[verb]["rule"]["%%ZONE_SOURCE%%"]["zone"],
rule[verb]["rule"]["%%ZONE_SOURCE%%"]["address"])
del rule[verb]["rule"]["%%ZONE_SOURCE%%"]
elif "%%ZONE_INTERFACE%%" in rule[verb]["rule"]:
zone_source = None
del rule[verb]["rule"]["%%ZONE_INTERFACE%%"]
else:
return
family = rule[verb]["rule"]["family"]
if zone_source and verb == "delete":
if family in zone_source_index_cache and \
zone_source in zone_source_index_cache[family]:
zone_source_index_cache[family].remove(zone_source)
elif verb != "delete":
if family not in zone_source_index_cache:
zone_source_index_cache[family] = []
if zone_source:
# order source based dispatch by zone name
if zone_source not in zone_source_index_cache[family]:
zone_source_index_cache[family].append(zone_source)
zone_source_index_cache[family].sort(key=lambda x: x[0])
index = zone_source_index_cache[family].index(zone_source)
else:
if self._fw._allow_zone_drifting:
index = 0
else:
index = len(zone_source_index_cache[family])
_verb_snippet = rule[verb]
del rule[verb]
if index == 0:
rule["insert"] = _verb_snippet
else:
index -= 1 # point to the rule before insertion point
rule["add"] = _verb_snippet
rule["add"]["rule"]["index"] = index
def reverse_rule(self, dict):
if "insert" in dict:
return {"delete": copy.deepcopy(dict["insert"])}
elif "add" in dict:
return {"delete": copy.deepcopy(dict["add"])}
else:
raise FirewallError(UNKNOWN_ERROR, "Failed to reverse rule")
def _set_rule_replace_rich_rule_priority(self, rule, rich_rule_priority_counts):
for verb in ["add", "insert", "delete"]:
if verb in rule:
break
if "%%RICH_RULE_PRIORITY%%" in rule[verb]["rule"]:
priority = rule[verb]["rule"]["%%RICH_RULE_PRIORITY%%"]
del rule[verb]["rule"]["%%RICH_RULE_PRIORITY%%"]
if type(priority) != int:
raise FirewallError(INVALID_RULE, "rich rule priority must be followed by a number")
chain = (rule[verb]["rule"]["family"], rule[verb]["rule"]["chain"]) # family, chain
# Add the rule to the priority counts. We don't need to store the
# rule, just bump the ref count for the priority value.
if verb == "delete":
if chain not in rich_rule_priority_counts or \
priority not in rich_rule_priority_counts[chain] or \
rich_rule_priority_counts[chain][priority] <= 0:
raise FirewallError(UNKNOWN_ERROR, "nonexistent or underflow of rich rule priority count")
rich_rule_priority_counts[chain][priority] -= 1
else:
if chain not in rich_rule_priority_counts:
rich_rule_priority_counts[chain] = {}
if priority not in rich_rule_priority_counts[chain]:
rich_rule_priority_counts[chain][priority] = 0
# calculate index of new rule
index = 0
for p in sorted(rich_rule_priority_counts[chain].keys()):
if p == priority and verb == "insert":
break
index += rich_rule_priority_counts[chain][p]
if p == priority and verb == "add":
break
rich_rule_priority_counts[chain][priority] += 1
_verb_snippet = rule[verb]
del rule[verb]
if index == 0:
rule["insert"] = _verb_snippet
else:
index -= 1 # point to the rule before insertion point
rule["add"] = _verb_snippet
rule["add"]["rule"]["index"] = index
def _get_rule_key(self, rule):
for verb in ["add", "insert", "delete"]:
if verb in rule and "rule" in rule[verb]:
rule_key = copy.deepcopy(rule[verb]["rule"])
for non_key in ["index", "handle", "position"]:
if non_key in rule_key:
del rule_key[non_key]
# str(rule_key) is insufficient because dictionary order is
# not stable.. so abuse the JSON library
rule_key = json.dumps(rule_key, sort_keys=True)
return rule_key
# Not a rule (it's a table, chain, etc)
return None
def set_rules(self, rules, log_denied):
_valid_verbs = ["add", "insert", "delete", "flush", "replace"]
_valid_add_verbs = ["add", "insert", "replace"]
_deduplicated_rules = []
_executed_rules = []
rich_rule_priority_counts = copy.deepcopy(self.rich_rule_priority_counts)
zone_source_index_cache = copy.deepcopy(self.zone_source_index_cache)
rule_ref_count = self.rule_ref_count.copy()
for rule in rules:
if type(rule) != dict:
raise FirewallError(UNKNOWN_ERROR, "rule must be a dictionary, rule: %s" % (rule))
for verb in _valid_verbs:
if verb in rule:
break
if verb not in rule:
raise FirewallError(INVALID_RULE, "no valid verb found, rule: %s" % (rule))
rule_key = self._get_rule_key(rule)
# rule deduplication
if rule_key in rule_ref_count:
log.debug2("%s: prev rule ref cnt %d, %s", self.__class__,
rule_ref_count[rule_key], rule_key)
if verb != "delete":
rule_ref_count[rule_key] += 1
continue
elif rule_ref_count[rule_key] > 1:
rule_ref_count[rule_key] -= 1
continue
elif rule_ref_count[rule_key] == 1:
rule_ref_count[rule_key] -= 1
else:
raise FirewallError(UNKNOWN_ERROR, "rule ref count bug: rule_key '%s', cnt %d"
% (rule_key, rule_ref_count[rule_key]))
elif rule_key and verb != "delete":
rule_ref_count[rule_key] = 1
_deduplicated_rules.append(rule)
_rule = copy.deepcopy(rule)
if rule_key:
# filter empty rule expressions. Rich rules add quite a bit of
# them, but it makes the rest of the code simpler. libnftables
# does not tolerate them.
_rule[verb]["rule"]["expr"] = list(filter(None, _rule[verb]["rule"]["expr"]))
self._set_rule_replace_rich_rule_priority(_rule, rich_rule_priority_counts)
self._run_replace_zone_source(_rule, zone_source_index_cache)
# delete using rule handle
if verb == "delete":
_rule = {"delete": {"rule": {"family": _rule["delete"]["rule"]["family"],
"table": _rule["delete"]["rule"]["table"],
"chain": _rule["delete"]["rule"]["chain"],
"handle": self.rule_to_handle[rule_key]}}}
_executed_rules.append(_rule)
json_blob = {"nftables": [{"metainfo": {"json_schema_version": 1}}] + _executed_rules}
if log.getDebugLogLevel() >= 3:
# guarded with if statement because json.dumps() is expensive.
log.debug3("%s: calling python-nftables with JSON blob: %s", self.__class__,
json.dumps(json_blob))
rc, output, error = self.nftables.json_cmd(json_blob)
if rc != 0:
raise ValueError("'%s' failed: %s\nJSON blob:\n%s" % ("python-nftables", error, json.dumps(json_blob)))
self.rich_rule_priority_counts = rich_rule_priority_counts
self.zone_source_index_cache = zone_source_index_cache
self.rule_ref_count = rule_ref_count
index = 0
for rule in _deduplicated_rules:
index += 1 # +1 due to metainfo
rule_key = self._get_rule_key(rule)
if not rule_key:
continue
if "delete" in rule:
del self.rule_to_handle[rule_key]
del self.rule_ref_count[rule_key]
continue
for verb in _valid_add_verbs:
if verb in output["nftables"][index]:
break
if verb not in output["nftables"][index]:
continue
self.rule_to_handle[rule_key] = output["nftables"][index][verb]["rule"]["handle"]
def set_rule(self, rule, log_denied):
self.set_rules([rule], log_denied)
return ""
def get_available_tables(self, table=None):
# Tables always exist in nftables
return [table] if table else IPTABLES_TO_NFT_HOOK.keys()
def build_flush_rules(self):
# Policy is stashed in a separate table that we're _not_ going to
# flush. As such, we retain the policy rule handles and ref counts.
saved_rule_to_handle = {}
saved_rule_ref_count = {}
for rule in self._build_set_policy_rules_ct_rules(True):
policy_key = self._get_rule_key(rule)
if policy_key in self.rule_to_handle:
saved_rule_to_handle[policy_key] = self.rule_to_handle[policy_key]
saved_rule_ref_count[policy_key] = self.rule_ref_count[policy_key]
self.rule_to_handle = saved_rule_to_handle
self.rule_ref_count = saved_rule_ref_count
self.rich_rule_priority_counts = {}
self.zone_source_index_cache = {}
rules = []
for family in ["inet", "ip", "ip6"]:
if TABLE_NAME in self.created_tables[family]:
rules.append({"delete": {"table": {"family": family,
"name": TABLE_NAME}}})
self.created_tables[family].remove(TABLE_NAME)
return rules
def _build_set_policy_rules_ct_rules(self, enable):
add_del = { True: "add", False: "delete" }[enable]
rules = []
for hook in ["input", "forward", "output"]:
rules.append({add_del: {"rule": {"family": "inet",
"table": TABLE_NAME_POLICY,
"chain": "%s_%s" % ("filter", hook),
"expr": [{"match": {"left": {"ct": {"key": "state"}},
"op": "in",
"right": {"set": ["established", "related"]}}},
{"accept": None}]}}})
return rules
def build_set_policy_rules(self, policy):
# Policy is not exposed to the user. It's only to make sure we DROP
# packets while reloading and for panic mode. As such, using hooks with
# a higher priority than our base chains is sufficient.
rules = []
if policy == "PANIC":
rules.append({"add": {"table": {"family": "inet",
"name": TABLE_NAME_POLICY}}})
self.created_tables["inet"].append(TABLE_NAME_POLICY)
# Use "raw" priority for panic mode. This occurs before
# conntrack, mangle, nat, etc
for hook in ["prerouting", "output"]:
rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME_POLICY,
"name": "%s_%s" % ("raw", hook),
"type": "filter",
"hook": hook,
"prio": -300 + NFT_HOOK_OFFSET - 1,
"policy": "drop"}}})
if policy == "DROP":
rules.append({"add": {"table": {"family": "inet",
"name": TABLE_NAME_POLICY}}})
self.created_tables["inet"].append(TABLE_NAME_POLICY)
# To drop everything except existing connections we use
# "filter" because it occurs _after_ conntrack.
for hook in ["input", "forward", "output"]:
rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME_POLICY,
"name": "%s_%s" % ("filter", hook),
"type": "filter",
"hook": hook,
"prio": 0 + NFT_HOOK_OFFSET - 1,
"policy": "drop"}}})
rules += self._build_set_policy_rules_ct_rules(True)
elif policy == "ACCEPT":
for rule in self._build_set_policy_rules_ct_rules(False):
policy_key = self._get_rule_key(rule)
if policy_key in self.rule_to_handle:
rules.append(rule)
if TABLE_NAME_POLICY in self.created_tables["inet"]:
rules.append({"delete": {"table": {"family": "inet",
"name": TABLE_NAME_POLICY}}})
self.created_tables["inet"].remove(TABLE_NAME_POLICY)
else:
FirewallError(UNKNOWN_ERROR, "not implemented")
return rules
def supported_icmp_types(self):
# nftables supports any icmp_type via arbitrary type/code matching.
# We just need a translation for it in ICMP_TYPES_FRAGMENTS.
supported = set()
for ipv in ICMP_TYPES_FRAGMENTS.keys():
supported.update(ICMP_TYPES_FRAGMENTS[ipv].keys())
return list(supported)
def build_default_tables(self):
default_tables = []
for family in ["inet", "ip", "ip6"]:
default_tables.append({"add": {"table": {"family": family,
"name": TABLE_NAME}}})
self.created_tables[family].append(TABLE_NAME)
return default_tables
def build_default_rules(self, log_denied="off"):
default_rules = []
for chain in IPTABLES_TO_NFT_HOOK["raw"].keys():
default_rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME,
"name": "raw_%s" % chain,
"type": "filter",
"hook": "%s" % IPTABLES_TO_NFT_HOOK["raw"][chain][0],
"prio": IPTABLES_TO_NFT_HOOK["raw"][chain][1]}}})
for chain in ["PREROUTING"]:
for dispatch_suffix in ["ZONES_SOURCE", "ZONES"] if self._fw._allow_zone_drifting else ["ZONES"]:
default_rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME,
"name": "raw_%s_%s" % (chain, dispatch_suffix)}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "raw_%s" % chain,
"expr": [{"jump": {"target": "raw_%s_%s" % (chain, dispatch_suffix)}}]}}})
for chain in IPTABLES_TO_NFT_HOOK["mangle"].keys():
default_rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME,
"name": "mangle_%s" % chain,
"type": "filter",
"hook": "%s" % IPTABLES_TO_NFT_HOOK["mangle"][chain][0],
"prio": IPTABLES_TO_NFT_HOOK["mangle"][chain][1]}}})
for dispatch_suffix in ["ZONES_SOURCE", "ZONES"] if self._fw._allow_zone_drifting else ["ZONES"]:
default_rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME,
"name": "mangle_%s_%s" % (chain, dispatch_suffix)}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "mangle_%s" % chain,
"expr": [{"jump": {"target": "mangle_%s_%s" % (chain, dispatch_suffix)}}]}}})
for family in ["ip", "ip6"]:
for chain in IPTABLES_TO_NFT_HOOK["nat"].keys():
default_rules.append({"add": {"chain": {"family": family,
"table": TABLE_NAME,
"name": "nat_%s" % chain,
"type": "nat",
"hook": "%s" % IPTABLES_TO_NFT_HOOK["nat"][chain][0],
"prio": IPTABLES_TO_NFT_HOOK["nat"][chain][1]}}})
for dispatch_suffix in ["ZONES_SOURCE", "ZONES"] if self._fw._allow_zone_drifting else ["ZONES"]:
default_rules.append({"add": {"chain": {"family": family,
"table": TABLE_NAME,
"name": "nat_%s_%s" % (chain, dispatch_suffix)}}})
default_rules.append({"add": {"rule": {"family": family,
"table": TABLE_NAME,
"chain": "nat_%s" % chain,
"expr": [{"jump": {"target": "nat_%s_%s" % (chain, dispatch_suffix)}}]}}})
for chain in IPTABLES_TO_NFT_HOOK["filter"].keys():
default_rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME,
"name": "filter_%s" % chain,
"type": "filter",
"hook": "%s" % IPTABLES_TO_NFT_HOOK["filter"][chain][0],
"prio": IPTABLES_TO_NFT_HOOK["filter"][chain][1]}}})
# filter, INPUT
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "INPUT",
"expr": [{"match": {"left": {"ct": {"key": "state"}},
"op": "in",
"right": {"set": ["established", "related"]}}},
{"accept": None}]}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "INPUT",
"expr": [{"match": {"left": {"ct": {"key": "status"}},
"op": "in",
"right": "dnat"}},
{"accept": None}]}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "INPUT",
"expr": [{"match": {"left": {"meta": {"key": "iifname"}},
"op": "==",
"right": "lo"}},
{"accept": None}]}}})
for dispatch_suffix in ["ZONES_SOURCE", "ZONES"] if self._fw._allow_zone_drifting else ["ZONES"]:
default_rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME,
"name": "filter_%s_%s" % ("INPUT", dispatch_suffix)}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "INPUT",
"expr": [{"jump": {"target": "filter_%s_%s" % ("INPUT", dispatch_suffix)}}]}}})
if log_denied != "off":
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "INPUT",
"expr": [{"match": {"left": {"ct": {"key": "state"}},
"op": "in",
"right": {"set": ["invalid"]}}},
self._pkttype_match_fragment(log_denied),
{"log": {"prefix": "STATE_INVALID_DROP: "}}]}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "INPUT",
"expr": [{"match": {"left": {"ct": {"key": "state"}},
"op": "in",
"right": {"set": ["invalid"]}}},
{"drop": None}]}}})
if log_denied != "off":
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "INPUT",
"expr": [self._pkttype_match_fragment(log_denied),
{"log": {"prefix": "FINAL_REJECT: "}}]}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "INPUT",
"expr": [{"reject": {"type": "icmpx", "expr": "admin-prohibited"}}]}}})
# filter, FORWARD
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "FORWARD",
"expr": [{"match": {"left": {"ct": {"key": "state"}},
"op": "in",
"right": {"set": ["established", "related"]}}},
{"accept": None}]}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "FORWARD",
"expr": [{"match": {"left": {"ct": {"key": "status"}},
"op": "in",
"right": "dnat"}},
{"accept": None}]}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "FORWARD",
"expr": [{"match": {"left": {"meta": {"key": "iifname"}},
"op": "==",
"right": "lo"}},
{"accept": None}]}}})
for direction in ["IN", "OUT"]:
for dispatch_suffix in ["ZONES_SOURCE", "ZONES"] if self._fw._allow_zone_drifting else ["ZONES"]:
default_rules.append({"add": {"chain": {"family": "inet",
"table": TABLE_NAME,
"name": "filter_%s_%s_%s" % ("FORWARD", direction, dispatch_suffix)}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "FORWARD",
"expr": [{"jump": {"target": "filter_%s_%s_%s" % ("FORWARD", direction, dispatch_suffix)}}]}}})
if log_denied != "off":
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "FORWARD",
"expr": [{"match": {"left": {"ct": {"key": "state"}},
"op": "in",
"right": {"set": ["invalid"]}}},
self._pkttype_match_fragment(log_denied),
{"log": {"prefix": "STATE_INVALID_DROP: "}}]}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "FORWARD",
"expr": [{"match": {"left": {"ct": {"key": "state"}},
"op": "in",
"right": {"set": ["invalid"]}}},
{"drop": None}]}}})
if log_denied != "off":
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "FORWARD",
"expr": [self._pkttype_match_fragment(log_denied),
{"log": {"prefix": "FINAL_REJECT: "}}]}}})
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_%s" % "FORWARD",
"expr": [{"reject": {"type": "icmpx", "expr": "admin-prohibited"}}]}}})
# filter, OUTPUT
default_rules.append({"add": {"rule": {"family": "inet",
"table": TABLE_NAME,
"chain": "filter_OUTPUT",
"expr": [{"match": {"left": {"meta": {"key": "oifname"}},
"op": "==",
"right": "lo"}},
{"accept": None}]}}})
return default_rules
def get_zone_table_chains(self, table):
if table == "filter":
return ["INPUT", "FORWARD_IN", "FORWARD_OUT"]
if table == "mangle":
return ["PREROUTING"]
if table == "nat":
return ["PREROUTING", "POSTROUTING"]
if table == "raw":
return ["PREROUTING"]
return []
def build_zone_source_interface_rules(self, enable, zone, policy, interface,
table, chain, append=False,
family="inet"):
# nat tables needs to use ip/ip6 family
if table == "nat" and family == "inet":
rules = []
rules.extend(self.build_zone_source_interface_rules(enable, zone, policy,
interface, table, chain, append, "ip"))
rules.extend(self.build_zone_source_interface_rules(enable, zone, policy,
interface, table, chain, append, "ip6"))
return rules
_policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
opt = {
"PREROUTING": "iifname",
"POSTROUTING": "oifname",
"INPUT": "iifname",
"FORWARD_IN": "iifname",
"FORWARD_OUT": "oifname",
"OUTPUT": "oifname",
}[chain]
if interface[len(interface)-1] == "+":
interface = interface[:len(interface)-1] + "*"
action = "goto"
if interface == "*":
expr_fragments = [{action: {"target": "%s_%s" % (table, _policy)}}]
else:
expr_fragments = [{"match": {"left": {"meta": {"key": opt}},
"op": "==",
"right": interface}},
{action: {"target": "%s_%s" % (table, _policy)}}]
if enable and not append:
verb = "insert"
rule = {"family": family,
"table": TABLE_NAME,
"chain": "%s_%s_ZONES" % (table, chain),
"expr": expr_fragments}
rule.update(self._zone_interface_fragment())
elif enable:
verb = "add"
rule = {"family": family,
"table": TABLE_NAME,
"chain": "%s_%s_ZONES" % (table, chain),
"expr": expr_fragments}
else:
verb = "delete"
rule = {"family": family,
"table": TABLE_NAME,
"chain": "%s_%s_ZONES" % (table, chain),
"expr": expr_fragments}
if not append:
rule.update(self._zone_interface_fragment())
return [{verb: {"rule": rule}}]
def build_zone_source_address_rules(self, enable, zone, policy,
address, table, chain, family="inet"):
# nat tables needs to use ip/ip6 family
if table == "nat" and family == "inet":
rules = []
if address.startswith("ipset:"):
ipset_family = self._set_get_family(address[len("ipset:"):])
else:
ipset_family = None
if check_address("ipv4", address) or check_mac(address) or ipset_family == "ip":
rules.extend(self.build_zone_source_address_rules(enable, zone, policy,
address, table, chain, "ip"))
if check_address("ipv6", address) or check_mac(address) or ipset_family == "ip6":
rules.extend(self.build_zone_source_address_rules(enable, zone, policy,
address, table, chain, "ip6"))
return rules
_policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
add_del = { True: "insert", False: "delete" }[enable]
opt = {
"PREROUTING": "saddr",
"POSTROUTING": "daddr",
"INPUT": "saddr",
"FORWARD_IN": "saddr",
"FORWARD_OUT": "daddr",
"OUTPUT": "daddr",
}[chain]
if self._fw._allow_zone_drifting:
zone_dispatch_chain = "%s_%s_ZONES_SOURCE" % (table, chain)
else:
zone_dispatch_chain = "%s_%s_ZONES" % (table, chain)
action = "goto"
rule = {"family": family,
"table": TABLE_NAME,
"chain": zone_dispatch_chain,
"expr": [self._rule_addr_fragment(opt, address),
{action: {"target": "%s_%s" % (table, _policy)}}]}
rule.update(self._zone_source_fragment(zone, address))
return [{add_del: {"rule": rule}}]
def build_policy_chain_rules(self, policy, table, family="inet"):
# nat tables needs to use ip/ip6 family
if table == "nat" and family == "inet":
rules = []
rules.extend(self.build_policy_chain_rules(policy, table, "ip"))
rules.extend(self.build_policy_chain_rules(policy, table, "ip6"))
return rules
_policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
rules = []
rules.append({"add": {"chain": {"family": family,
"table": TABLE_NAME,
"name": "%s_%s" % (table, _policy)}}})
for chain_suffix in ["pre", "log", "deny", "allow", "post"]:
rules.append({"add": {"chain": {"family": family,
"table": TABLE_NAME,
"name": "%s_%s_%s" % (table, _policy, chain_suffix)}}})
for chain_suffix in ["pre", "log", "deny", "allow", "post"]:
rules.append({"add": {"rule": {"family": family,
"table": TABLE_NAME,
"chain": "%s_%s" % (table, _policy),
"expr": [{"jump": {"target": "%s_%s_%s" % (table, _policy, chain_suffix)}}]}}})
target = self._fw.policy._policies[policy].target
if self._fw.get_log_denied() != "off":
if table == "filter":
if target in ["REJECT", "%%REJECT%%", "DROP"]:
log_suffix = target
if target == "%%REJECT%%":
log_suffix = "REJECT"
rules.append({"add": {"rule": {"family": family,
"table": TABLE_NAME,
"chain": "%s_%s" % (table, _policy),
"expr": [self._pkttype_match_fragment(self._fw.get_log_denied()),
{"log": {"prefix": "\"filter_%s_%s: \"" % (_policy, log_suffix)}}]}}})
if table == "filter" and \
target in ["ACCEPT", "REJECT", "%%REJECT%%", "DROP"]:
if target == "%%REJECT%%":
target_fragment = self._reject_fragment()
else:
target_fragment = {target.lower(): None}
rules.append({"add": {"rule": {"family": family,
"table": TABLE_NAME,
"chain": "%s_%s" % (table, _policy),
"expr": [target_fragment]}}})
return rules
def _pkttype_match_fragment(self, pkttype):
if pkttype == "all":
return {}
elif pkttype in ["unicast", "broadcast", "multicast"]:
return {"match": {"left": {"meta": {"key": "pkttype"}},
"op": "==",
"right": pkttype}}
raise FirewallError(INVALID_RULE, "Invalid pkttype \"%s\"", pkttype)
def _reject_types_fragment(self, reject_type):
frags = {
# REJECT_TYPES : <nft reject rule fragment>
"icmp-host-prohibited" : {"reject": {"type": "icmp", "expr": "host-prohibited"}},
"host-prohib" : {"reject": {"type": "icmp", "expr": "host-prohibited"}},
"icmp-net-prohibited" : {"reject": {"type": "icmp", "expr": "net-prohibited"}},
"net-prohib" : {"reject": {"type": "icmp", "expr": "net-prohibited"}},
"icmp-admin-prohibited" : {"reject": {"type": "icmp", "expr": "admin-prohibited"}},
"admin-prohib" : {"reject": {"type": "icmp", "expr": "admin-prohibited"}},
"icmp6-adm-prohibited" : {"reject": {"type": "icmpv6", "expr": "admin-prohibited"}},
"adm-prohibited" : {"reject": {"type": "icmpv6", "expr": "admin-prohibited"}},
"icmp-net-unreachable" : {"reject": {"type": "icmp", "expr": "net-unreachable"}},
"net-unreach" : {"reject": {"type": "icmp", "expr": "net-unreachable"}},
"icmp-host-unreachable" : {"reject": {"type": "icmp", "expr": "host-unreachable"}},
"host-unreach" : {"reject": {"type": "icmp", "expr": "host-unreachable"}},
"icmp-port-unreachable" : {"reject": {"type": "icmp", "expr": "port-unreachable"}},
"icmp6-port-unreachable" : {"reject": {"type": "icmpv6", "expr": "port-unreachable"}},
"port-unreach" : {"reject": {"type": "icmpx", "expr": "port-unreachable"}},
"icmp-proto-unreachable" : {"reject": {"type": "icmp", "expr": "prot-unreachable"}},
"proto-unreach" : {"reject": {"type": "icmp", "expr": "prot-unreachable"}},
"icmp6-addr-unreachable" : {"reject": {"type": "icmpv6", "expr": "addr-unreachable"}},
"addr-unreach" : {"reject": {"type": "icmpv6", "expr": "addr-unreachable"}},
"icmp6-no-route" : {"reject": {"type": "icmpv6", "expr": "no-route"}},
"no-route" : {"reject": {"type": "icmpv6", "expr": "no-route"}},
"tcp-reset" : {"reject": {"type": "tcp reset"}},
"tcp-rst" : {"reject": {"type": "tcp reset"}},
}
return frags[reject_type]
def _reject_fragment(self):
return {"reject": {"type": "icmpx",
"expr": "admin-prohibited"}}
def _icmp_match_fragment(self):
return {"match": {"left": {"meta": {"key": "l4proto"}},
"op": "==",
"right": {"set": ["icmp", "icmpv6"]}}}
def _rich_rule_limit_fragment(self, limit):
if not limit:
return {}
rich_to_nft = {
"s" : "second",
"m" : "minute",
"h" : "hour",
"d" : "day",
}
try:
i = limit.value.index("/")
except ValueError:
raise FirewallError(INVALID_RULE, "Expected '/' in limit")
return {"limit": {"rate": int(limit.value[0:i]),
"per": rich_to_nft[limit.value[i+1]]}}
def _rich_rule_chain_suffix(self, rich_rule):
if type(rich_rule.element) in [Rich_Masquerade, Rich_ForwardPort, Rich_IcmpBlock]:
# These are special and don't have an explicit action
pass
elif rich_rule.action:
if type(rich_rule.action) not in [Rich_Accept, Rich_Reject, Rich_Drop, Rich_Mark]:
raise FirewallError(INVALID_RULE, "Unknown action %s" % type(rich_rule.action))
else:
raise FirewallError(INVALID_RULE, "No rule action specified.")
if rich_rule.priority == 0:
if type(rich_rule.element) in [Rich_Masquerade, Rich_ForwardPort] or \
type(rich_rule.action) in [Rich_Accept, Rich_Mark]:
return "allow"
elif type(rich_rule.element) in [Rich_IcmpBlock] or \
type(rich_rule.action) in [Rich_Reject, Rich_Drop]:
return "deny"
elif rich_rule.priority < 0:
return "pre"
else:
return "post"
def _rich_rule_chain_suffix_from_log(self, rich_rule):
if not rich_rule.log and not rich_rule.audit:
raise FirewallError(INVALID_RULE, "Not log or audit")
if rich_rule.priority == 0:
return "log"
elif rich_rule.priority < 0:
return "pre"
else:
return "post"
def _zone_interface_fragment(self):
return {"%%ZONE_INTERFACE%%": None}
def _zone_source_fragment(self, zone, address):
if check_single_address("ipv6", address):
address = normalizeIP6(address)
elif check_address("ipv6", address):
addr_split = address.split("/")
address = normalizeIP6(addr_split[0]) + "/" + addr_split[1]
return {"%%ZONE_SOURCE%%": {"zone": zone, "address": address}}
def _rich_rule_priority_fragment(self, rich_rule):
if not rich_rule or rich_rule.priority == 0:
return {}
return {"%%RICH_RULE_PRIORITY%%": rich_rule.priority}
def _rich_rule_log(self, policy, rich_rule, enable, table, expr_fragments):
if not rich_rule.log:
return {}
_policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
add_del = { True: "add", False: "delete" }[enable]
chain_suffix = self._rich_rule_chain_suffix_from_log(rich_rule)
log_options = {}
if rich_rule.log.prefix:
log_options["prefix"] = "%s" % rich_rule.log.prefix
if rich_rule.log.level:
log_options["level"] = "%s" % rich_rule.log.level
rule = {"family": "inet",
"table": TABLE_NAME,
"chain": "%s_%s_%s" % (table, _policy, chain_suffix),
"expr": expr_fragments +
[{"log": log_options},
self._rich_rule_limit_fragment(rich_rule.log.limit)]}
rule.update(self._rich_rule_priority_fragment(rich_rule))
return {add_del: {"rule": rule}}
def _rich_rule_audit(self, policy, rich_rule, enable, table, expr_fragments):