From 0de3de1e0a78eb35b666b8f613d3e54fd3ad54e4 Mon Sep 17 00:00:00 2001 From: sarthurdev <965089+sarthurdev@users.noreply.github.com> Date: Tue, 5 Sep 2023 14:51:16 +0200 Subject: interface: T5550: Interface source-validation priority over global value - Migrate IPv4 source-validation to nftables - Interface source-validation value takes priority, fallback to global value --- data/templates/firewall/nftables.j2 | 21 ++++++--- data/vyos-firewall-init.conf | 14 ++++++ python/vyos/ifconfig/interface.py | 61 +++++++++++---------------- smoketest/scripts/cli/base_interfaces_test.py | 8 +++- 4 files changed, 58 insertions(+), 46 deletions(-) diff --git a/data/templates/firewall/nftables.j2 b/data/templates/firewall/nftables.j2 index 0fbddfaa9..d7660c37b 100644 --- a/data/templates/firewall/nftables.j2 +++ b/data/templates/firewall/nftables.j2 @@ -5,29 +5,36 @@ flush chain raw FW_CONNTRACK flush chain ip6 raw FW_CONNTRACK +flush chain raw vyos_global_rpfilter +flush chain ip6 raw vyos_global_rpfilter + table raw { chain FW_CONNTRACK { {{ ipv4_conntrack_action }} } + + chain vyos_global_rpfilter { +{% if global_options.source_validation is vyos_defined('loose') %} + fib saddr oif 0 counter drop +{% elif global_options.source_validation is vyos_defined('strict') %} + fib saddr . iif oif 0 counter drop +{% endif %} + return + } } table ip6 raw { chain FW_CONNTRACK { {{ ipv6_conntrack_action }} } -} -{% if first_install is not vyos_defined %} -delete table inet vyos_global_rpfilter -{% endif %} -table inet vyos_global_rpfilter { - chain PREROUTING { - type filter hook prerouting priority -300; policy accept; + chain vyos_global_rpfilter { {% if global_options.source_validation is vyos_defined('loose') %} fib saddr oif 0 counter drop {% elif global_options.source_validation is vyos_defined('strict') %} fib saddr . iif oif 0 counter drop {% endif %} + return } } diff --git a/data/vyos-firewall-init.conf b/data/vyos-firewall-init.conf index 41e7627f5..b0026fdf3 100644 --- a/data/vyos-firewall-init.conf +++ b/data/vyos-firewall-init.conf @@ -19,6 +19,15 @@ table raw { type filter hook forward priority -300; policy accept; } + chain vyos_global_rpfilter { + return + } + + chain vyos_rpfilter { + type filter hook prerouting priority -300; policy accept; + counter jump vyos_global_rpfilter + } + chain PREROUTING { type filter hook prerouting priority -300; policy accept; counter jump VYOS_CT_IGNORE @@ -82,8 +91,13 @@ table ip6 raw { type filter hook forward priority -300; policy accept; } + chain vyos_global_rpfilter { + return + } + chain vyos_rpfilter { type filter hook prerouting priority -300; policy accept; + counter jump vyos_global_rpfilter } chain PREROUTING { diff --git a/python/vyos/ifconfig/interface.py b/python/vyos/ifconfig/interface.py index 53256abb7..050095364 100644 --- a/python/vyos/ifconfig/interface.py +++ b/python/vyos/ifconfig/interface.py @@ -174,10 +174,6 @@ class Interface(Control): 'validate': assert_boolean, 'location': '/proc/sys/net/ipv4/conf/{ifname}/bc_forwarding', }, - 'rp_filter': { - 'validate': lambda flt: assert_range(flt,0,3), - 'location': '/proc/sys/net/ipv4/conf/{ifname}/rp_filter', - }, 'ipv6_accept_ra': { 'validate': lambda ara: assert_range(ara,0,3), 'location': '/proc/sys/net/ipv6/conf/{ifname}/accept_ra', @@ -251,9 +247,6 @@ class Interface(Control): 'ipv4_directed_broadcast': { 'location': '/proc/sys/net/ipv4/conf/{ifname}/bc_forwarding', }, - 'rp_filter': { - 'location': '/proc/sys/net/ipv4/conf/{ifname}/rp_filter', - }, 'ipv6_accept_ra': { 'location': '/proc/sys/net/ipv6/conf/{ifname}/accept_ra', }, @@ -763,44 +756,36 @@ class Interface(Control): return None return self.set_interface('ipv4_directed_broadcast', forwarding) - def set_ipv4_source_validation(self, value): + def _cleanup_ipv4_source_validation_rules(self, ifname): + results = self._cmd(f'nft -a list chain ip raw vyos_rpfilter').split("\n") + for line in results: + if f'iifname "{ifname}"' in line: + handle_search = re.search('handle (\d+)', line) + if handle_search: + self._cmd(f'nft delete rule ip raw vyos_rpfilter handle {handle_search[1]}') + + def set_ipv4_source_validation(self, mode): """ - Help prevent attacks used by Spoofing IP Addresses. Reverse path - filtering is a Kernel feature that, when enabled, is designed to ensure - packets that are not routable to be dropped. The easiest example of this - would be and IP Address of the range 10.0.0.0/8, a private IP Address, - being received on the Internet facing interface of the router. + Set IPv4 reverse path validation - As per RFC3074. + Example: + >>> from vyos.ifconfig import Interface + >>> Interface('eth0').set_ipv4_source_validation('strict') """ # Don't allow for netns yet if 'netns' in self.config: return None - if value == 'strict': - value = 1 - elif value == 'loose': - value = 2 - else: - value = 0 - - all_rp_filter = int(read_file('/proc/sys/net/ipv4/conf/all/rp_filter')) - if all_rp_filter > value: - global_setting = 'disable' - if all_rp_filter == 1: global_setting = 'strict' - elif all_rp_filter == 2: global_setting = 'loose' - - from vyos.base import Warning - Warning(f'Global source-validation is set to "{global_setting}", this '\ - f'overrides per interface setting on "{self.ifname}"!') - - tmp = self.get_interface('rp_filter') - if int(tmp) == value: - return None - return self.set_interface('rp_filter', value) + self._cleanup_ipv4_source_validation_rules(self.ifname) + nft_prefix = f'nft insert rule ip raw vyos_rpfilter iifname "{self.ifname}"' + if mode in ['strict', 'loose']: + self._cmd(f"{nft_prefix} counter return") + if mode == 'strict': + self._cmd(f"{nft_prefix} fib saddr . iif oif 0 counter drop") + elif mode == 'loose': + self._cmd(f"{nft_prefix} fib saddr oif 0 counter drop") def _cleanup_ipv6_source_validation_rules(self, ifname): - commands = [] results = self._cmd(f'nft -a list chain ip6 raw vyos_rpfilter').split("\n") for line in results: if f'iifname "{ifname}"' in line: @@ -821,7 +806,9 @@ class Interface(Control): return None self._cleanup_ipv6_source_validation_rules(self.ifname) - nft_prefix = f'nft add rule ip6 raw vyos_rpfilter iifname "{self.ifname}"' + nft_prefix = f'nft insert rule ip6 raw vyos_rpfilter iifname "{self.ifname}"' + if mode in ['strict', 'loose']: + self._cmd(f"{nft_prefix} counter return") if mode == 'strict': self._cmd(f"{nft_prefix} fib saddr . iif oif 0 counter drop") elif mode == 'loose': diff --git a/smoketest/scripts/cli/base_interfaces_test.py b/smoketest/scripts/cli/base_interfaces_test.py index 820024dc9..51ccbc9e6 100644 --- a/smoketest/scripts/cli/base_interfaces_test.py +++ b/smoketest/scripts/cli/base_interfaces_test.py @@ -834,8 +834,12 @@ class BasicInterfaceTest: self.assertEqual('1', tmp) if cli_defined(self._base_path + ['ip'], 'source-validation'): - tmp = read_file(f'{proc_base}/rp_filter') - self.assertEqual('2', tmp) + base_options = f'iifname "{interface}"' + out = cmd('sudo nft list chain ip raw vyos_rpfilter') + for line in out.splitlines(): + if line.startswith(base_options): + self.assertIn('fib saddr oif 0', line) + self.assertIn('drop', line) def test_interface_ipv6_options(self): if not self._test_ipv6: -- cgit v1.2.3