diff options
Diffstat (limited to 'src/conf_mode/service_snmp.py')
| -rwxr-xr-x | src/conf_mode/service_snmp.py | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/src/conf_mode/service_snmp.py b/src/conf_mode/service_snmp.py new file mode 100755 index 000000000..6565ffd60 --- /dev/null +++ b/src/conf_mode/service_snmp.py @@ -0,0 +1,269 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2018-2023 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 sys import exit + +from vyos.base import Warning +from vyos.config import Config +from vyos.configdict import dict_merge +from vyos.configverify import verify_vrf +from vyos.snmpv3_hashgen import plaintext_to_md5 +from vyos.snmpv3_hashgen import plaintext_to_sha1 +from vyos.snmpv3_hashgen import random +from vyos.template import render +from vyos.utils.process import call +from vyos.utils.permission import chmod_755 +from vyos.utils.dict import dict_search +from vyos.utils.network import is_addr_assigned +from vyos.version import get_version_data +from vyos import ConfigError +from vyos import airbag +airbag.enable() + +config_file_client = r'/etc/snmp/snmp.conf' +config_file_daemon = r'/etc/snmp/snmpd.conf' +config_file_access = r'/usr/share/snmp/snmpd.conf' +config_file_user = r'/var/lib/snmp/snmpd.conf' +systemd_override = r'/run/systemd/system/snmpd.service.d/override.conf' +systemd_service = 'snmpd.service' + +def get_config(config=None): + if config: + conf = config + else: + conf = Config() + base = ['service', 'snmp'] + + snmp = conf.get_config_dict(base, key_mangling=('-', '_'), + get_first_key=True, no_tag_node_value_mangle=True) + if not conf.exists(base): + snmp.update({'deleted' : ''}) + + if conf.exists(['service', 'lldp', 'snmp']): + snmp.update({'lldp_snmp' : ''}) + + if 'deleted' in snmp: + return snmp + + version_data = get_version_data() + snmp['version'] = version_data['version'] + + # create an internal snmpv3 user of the form 'vyosxxxxxxxxxxxxxxxx' + snmp['vyos_user'] = 'vyos' + random(8) + snmp['vyos_user_pass'] = random(16) + + # We have gathered the dict representation of the CLI, but there are default + # options which we need to update into the dictionary retrived. + snmp = conf.merge_defaults(snmp, recursive=True) + + if 'listen_address' in snmp: + # Always listen on localhost if an explicit address has been configured + # This is a safety measure to not end up with invalid listen addresses + # that are not configured on this system. See https://vyos.dev/T850 + if '127.0.0.1' not in snmp['listen_address']: + tmp = {'127.0.0.1': {'port': '161'}} + snmp['listen_address'] = dict_merge(tmp, snmp['listen_address']) + + if '::1' not in snmp['listen_address']: + tmp = {'::1': {'port': '161'}} + snmp['listen_address'] = dict_merge(tmp, snmp['listen_address']) + + return snmp + +def verify(snmp): + if 'deleted' in snmp: + return None + + if {'deleted', 'lldp_snmp'} <= set(snmp): + raise ConfigError('Can not delete SNMP service, as LLDP still uses SNMP!') + + ### check if the configured script actually exist + if 'script_extensions' in snmp and 'extension_name' in snmp['script_extensions']: + for extension, extension_opt in snmp['script_extensions']['extension_name'].items(): + if 'script' not in extension_opt: + raise ConfigError(f'Script extension "{extension}" requires an actual script to be configured!') + + tmp = extension_opt['script'] + if not os.path.isfile(tmp): + Warning(f'script "{tmp}" does not exist!') + else: + chmod_755(extension_opt['script']) + + if 'listen_address' in snmp: + for address in snmp['listen_address']: + # We only wan't to configure addresses that exist on the system. + # Hint the user if they don't exist + if 'vrf' in snmp: + vrf_name = snmp['vrf'] + if not is_addr_assigned(address, vrf_name) and address not in ['::1','127.0.0.1']: + raise ConfigError(f'SNMP listen address "{address}" not configured in vrf "{vrf_name}"!') + elif not is_addr_assigned(address): + raise ConfigError(f'SNMP listen address "{address}" not configured in default vrf!') + + if 'trap_target' in snmp: + for trap, trap_config in snmp['trap_target'].items(): + if 'community' not in trap_config: + raise ConfigError(f'Trap target "{trap}" requires a community to be set!') + + if 'oid_enable' in snmp: + Warning(f'Custom OIDs are enabled and may lead to system instability and high resource consumption') + + + verify_vrf(snmp) + + # bail out early if SNMP v3 is not configured + if 'v3' not in snmp: + return None + + if 'user' in snmp['v3']: + for user, user_config in snmp['v3']['user'].items(): + if 'group' not in user_config: + raise ConfigError(f'Group membership required for user "{user}"!') + + if 'plaintext_password' not in user_config['auth'] and 'encrypted_password' not in user_config['auth']: + raise ConfigError(f'Must specify authentication encrypted-password or plaintext-password for user "{user}"!') + + if 'plaintext_password' not in user_config['privacy'] and 'encrypted_password' not in user_config['privacy']: + raise ConfigError(f'Must specify privacy encrypted-password or plaintext-password for user "{user}"!') + + if 'group' in snmp['v3']: + for group, group_config in snmp['v3']['group'].items(): + if 'seclevel' not in group_config: + raise ConfigError(f'Must configure "seclevel" for group "{group}"!') + if 'view' not in group_config: + raise ConfigError(f'Must configure "view" for group "{group}"!') + + # Check if 'view' exists + view = group_config['view'] + if 'view' not in snmp['v3'] or view not in snmp['v3']['view']: + raise ConfigError(f'You must create view "{view}" first!') + + if 'view' in snmp['v3']: + for view, view_config in snmp['v3']['view'].items(): + if 'oid' not in view_config: + raise ConfigError(f'Must configure an "oid" for view "{view}"!') + + if 'trap_target' in snmp['v3']: + for trap, trap_config in snmp['v3']['trap_target'].items(): + if 'plaintext_password' not in trap_config['auth'] and 'encrypted_password' not in trap_config['auth']: + raise ConfigError(f'Must specify one of authentication encrypted-password or plaintext-password for trap "{trap}"!') + + if {'plaintext_password', 'encrypted_password'} <= set(trap_config['auth']): + raise ConfigError(f'Can not specify both authentication encrypted-password and plaintext-password for trap "{trap}"!') + + if 'plaintext_password' not in trap_config['privacy'] and 'encrypted_password' not in trap_config['privacy']: + raise ConfigError(f'Must specify one of privacy encrypted-password or plaintext-password for trap "{trap}"!') + + if {'plaintext_password', 'encrypted_password'} <= set(trap_config['privacy']): + raise ConfigError(f'Can not specify both privacy encrypted-password and plaintext-password for trap "{trap}"!') + + if 'type' not in trap_config: + raise ConfigError('SNMP v3 trap "type" must be specified!') + + return None + +def generate(snmp): + # As we are manipulating the snmpd user database we have to stop it first! + # This is even save if service is going to be removed + call(f'systemctl stop {systemd_service}') + # Clean config files + config_files = [config_file_client, config_file_daemon, + config_file_access, config_file_user, systemd_override] + for file in config_files: + if os.path.isfile(file): + os.unlink(file) + + if 'deleted' in snmp: + return None + + if 'v3' in snmp: + # net-snmp is now regenerating the configuration file in the background + # thus we need to re-open and re-read the file as the content changed. + # After that we can no read the encrypted password from the config and + # replace the CLI plaintext password with its encrypted version. + os.environ['vyos_libexec_dir'] = '/usr/libexec/vyos' + + if 'user' in snmp['v3']: + for user, user_config in snmp['v3']['user'].items(): + if dict_search('auth.type', user_config) == 'sha': + hash = plaintext_to_sha1 + else: + hash = plaintext_to_md5 + + if dict_search('auth.plaintext_password', user_config) is not None: + tmp = hash(dict_search('auth.plaintext_password', user_config), + dict_search('v3.engineid', snmp)) + + snmp['v3']['user'][user]['auth']['encrypted_password'] = tmp + del snmp['v3']['user'][user]['auth']['plaintext_password'] + + call(f'/opt/vyatta/sbin/my_set service snmp v3 user "{user}" auth encrypted-password "{tmp}" > /dev/null') + call(f'/opt/vyatta/sbin/my_delete service snmp v3 user "{user}" auth plaintext-password > /dev/null') + + if dict_search('privacy.plaintext_password', user_config) is not None: + tmp = hash(dict_search('privacy.plaintext_password', user_config), + dict_search('v3.engineid', snmp)) + + snmp['v3']['user'][user]['privacy']['encrypted_password'] = tmp + del snmp['v3']['user'][user]['privacy']['plaintext_password'] + + call(f'/opt/vyatta/sbin/my_set service snmp v3 user "{user}" privacy encrypted-password "{tmp}" > /dev/null') + call(f'/opt/vyatta/sbin/my_delete service snmp v3 user "{user}" privacy plaintext-password > /dev/null') + + # Write client config file + render(config_file_client, 'snmp/etc.snmp.conf.j2', snmp) + # Write server config file + render(config_file_daemon, 'snmp/etc.snmpd.conf.j2', snmp) + # Write access rights config file + render(config_file_access, 'snmp/usr.snmpd.conf.j2', snmp) + # Write access rights config file + render(config_file_user, 'snmp/var.snmpd.conf.j2', snmp) + # Write daemon configuration file + render(systemd_override, 'snmp/override.conf.j2', snmp) + + return None + +def apply(snmp): + # Always reload systemd manager configuration + call('systemctl daemon-reload') + + if 'deleted' in snmp: + return None + + # start SNMP daemon + call(f'systemctl restart {systemd_service}') + + # Enable AgentX in FRR + # This should be done for each daemon individually because common command + # works only if all the daemons started with SNMP support + # Following daemons from FRR 9.0/stable have SNMP module compiled in VyOS + frr_daemons_list = ['zebra', 'bgpd', 'ospf6d', 'ospfd', 'ripd', 'isisd', 'ldpd'] + for frr_daemon in frr_daemons_list: + call(f'vtysh -c "configure terminal" -d {frr_daemon} -c "agentx" >/dev/null') + + return None + +if __name__ == '__main__': + try: + c = get_config() + verify(c) + generate(c) + apply(c) + except ConfigError as e: + print(e) + exit(1) |