zone-policy: T2199: Migrate zone-policy to XML/Python

1 files changed, 176 insertions, 0 deletions

diff --git a/src/conf_mode/zone_policy.py b/src/conf_mode/zone_policy.py
new file mode 100755
index 000000000..92f5624c2
--- /dev/null
+++ b/src/conf_mode/zone_policy.py
@@ -0,0 +1,176 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later 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
+
+from json import loads
+from sys import exit
+
+from vyos.config import Config
+from vyos.template import render
+from vyos.util import cmd
+from vyos.util import dict_search_args
+from vyos.util import run
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+nftables_conf = '/run/nftables_zone.conf'
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['zone-policy']
+    zone_policy = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True,
+                                    no_tag_node_value_mangle=True)
+
+    if zone_policy:
+        zone_policy['firewall'] = conf.get_config_dict(['firewall'], key_mangling=('-', '_'), get_first_key=True,
+                                    no_tag_node_value_mangle=True)
+
+    return zone_policy
+
+def verify(zone_policy):
+    # bail out early - looks like removal from running config
+    if not zone_policy:
+        return None
+
+    local_zone = False
+    interfaces = []
+
+    if 'zone' in zone_policy:
+        for zone, zone_conf in zone_policy['zone'].items():
+            if 'local_zone' not in zone_conf and 'interface' not in zone_conf:
+                raise ConfigError(f'Zone "{zone}" has no interfaces and is not the local zone')
+
+            if 'local_zone' in zone_conf:
+                if local_zone:
+                    raise ConfigError('There cannot be multiple local zones')
+                if 'interface' in zone_conf:
+                    raise ConfigError('Local zone cannot have interfaces assigned')
+                local_zone = True
+
+            if 'interface' in zone_conf:
+                found_duplicates = [intf for intf in zone_conf['interface'] if intf in interfaces]
+
+                if found_duplicates:
+                    raise ConfigError(f'Interfaces cannot be assigned to multiple zones')
+
+                interfaces += zone_conf['interface']
+
+            if 'from' in zone_conf:
+                for from_zone, from_conf in zone_conf['from'].items():
+                    v4_name = dict_search_args(from_conf, 'firewall', 'name')
+                    if v4_name:
+                        if 'name' not in zone_policy['firewall']:
+                            raise ConfigError(f'Firewall name "{v4_name}" does not exist')
+
+                        if not dict_search_args(zone_policy, 'firewall', 'name', v4_name):
+                            raise ConfigError(f'Firewall name "{v4_name}" does not exist')
+
+                    v6_name = dict_search_args(from_conf, 'firewall', 'v6_name')
+                    if v6_name:
+                        if 'ipv6_name' not in zone_policy['firewall']:
+                            raise ConfigError(f'Firewall ipv6-name "{v6_name}" does not exist')
+
+                        if not dict_search_args(zone_policy, 'firewall', 'ipv6_name', v6_name):
+                            raise ConfigError(f'Firewall ipv6-name "{v6_name}" does not exist')
+
+    return None
+
+def has_ipv4_fw(zone_conf):
+    if 'from' not in zone_conf:
+        return False
+    zone_from = zone_conf['from']
+    return any([True for fz in zone_from if dict_search_args(zone_from, fz, 'firewall', 'name')])
+
+def has_ipv6_fw(zone_conf):
+    if 'from' not in zone_conf:
+        return False
+    zone_from = zone_conf['from']
+    return any([True for fz in zone_from if dict_search_args(zone_from, fz, 'firewall', 'ipv6_name')])
+
+def get_local_from(zone_policy, local_zone_name):
+    # Get all zone firewall names from the local zone
+    out = {}
+    for zone, zone_conf in zone_policy['zone'].items():
+        if zone == local_zone_name:
+            continue
+        if 'from' not in zone_conf:
+            continue
+        if local_zone_name in zone_conf['from']:
+            out[zone] = zone_conf['from'][local_zone_name]
+    return out
+
+def cleanup_commands():
+    commands = []
+    for table in ['ip filter', 'ip6 filter']:
+        json_str = cmd(f'nft -j list table {table}')
+        obj = loads(json_str)
+        if 'nftables' not in obj:
+            continue
+        for item in obj['nftables']:
+            if 'rule' in item:
+                chain = item['rule']['chain']
+                handle = item['rule']['handle']
+                if 'expr' not in item['rule']:
+                    continue
+                for expr in item['rule']['expr']:
+                    target = dict_search_args(expr, 'jump', 'target')
+                    if target and target.startswith("VZONE"):
+                        commands.append(f'delete rule {table} {chain} handle {handle}')
+        for item in obj['nftables']:
+            if 'chain' in item:
+                if item['chain']['name'].startswith("VZONE"):
+                    chain = item['chain']['name']
+                    commands.append(f'delete chain {table} {chain}')
+    return commands
+
+def generate(zone_policy):
+    data = zone_policy or {}
+
+    if os.path.exists(nftables_conf): # Check to see if we've run before
+        data['cleanup_commands'] = cleanup_commands()
+
+    if 'zone' in data:
+        for zone, zone_conf in data['zone'].items():
+            zone_conf['ipv4'] = has_ipv4_fw(zone_conf)
+            zone_conf['ipv6'] = has_ipv6_fw(zone_conf)
+
+            if 'local_zone' in zone_conf:
+                zone_conf['from_local'] = get_local_from(data, zone)
+
+    render(nftables_conf, 'zone_policy/nftables.tmpl', data)
+    return None
+
+def apply(zone_policy):
+    install_result = run(f'nft -f {nftables_conf}')
+    if install_result == 1:
+        raise ConfigError('Failed to apply zone-policy')
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)