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#!/usr/bin/env python3
#
# Copyright (C) 2018-2024 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 syslog import syslog
from syslog import LOG_INFO
from vyos.config import Config
from vyos.configdict import is_node_changed
from vyos.configverify import verify_vrf
from vyos.configverify import verify_pki_ca_certificate
from vyos.utils.process import call
from vyos.template import render
from vyos import ConfigError
from vyos import airbag
from vyos.pki import find_chain
from vyos.pki import encode_certificate
from vyos.pki import load_certificate
from vyos.utils.file import write_file
airbag.enable()
config_file = r'/run/sshd/sshd_config'
sshguard_config_file = '/etc/sshguard/sshguard.conf'
sshguard_whitelist = '/etc/sshguard/whitelist'
key_rsa = '/etc/ssh/ssh_host_rsa_key'
key_dsa = '/etc/ssh/ssh_host_dsa_key'
key_ed25519 = '/etc/ssh/ssh_host_ed25519_key'
trusted_user_ca_key = '/etc/ssh/trusted_user_ca_key'
def get_config(config=None):
if config:
conf = config
else:
conf = Config()
base = ['service', 'ssh']
if not conf.exists(base):
return None
ssh = conf.get_config_dict(
base, key_mangling=('-', '_'), get_first_key=True, with_pki=True
)
tmp = is_node_changed(conf, base + ['vrf'])
if tmp:
ssh.update({'restart_required': {}})
# We have gathered the dict representation of the CLI, but there are default
# options which we need to update into the dictionary retrived.
ssh = conf.merge_defaults(ssh, recursive=True)
# pass config file path - used in override template
ssh['config_file'] = config_file
# Ignore default XML values if config doesn't exists
# Delete key from dict
if not conf.exists(base + ['dynamic-protection']):
del ssh['dynamic_protection']
return ssh
def verify(ssh):
if not ssh:
return None
if 'rekey' in ssh and 'data' not in ssh['rekey']:
raise ConfigError('Rekey data is required!')
if 'trusted_user_ca_key' in ssh:
if 'ca_certificate' not in ssh['trusted_user_ca_key']:
raise ConfigError('CA certificate is required for TrustedUserCAKey')
ca_key_name = ssh['trusted_user_ca_key']['ca_certificate']
verify_pki_ca_certificate(ssh, ca_key_name)
pki_ca_cert = ssh['pki']['ca'][ca_key_name]
if 'certificate' not in pki_ca_cert or not pki_ca_cert['certificate']:
raise ConfigError(f"CA certificate '{ca_key_name}' is not valid or missing")
verify_vrf(ssh)
return None
def generate(ssh):
if not ssh:
if os.path.isfile(config_file):
os.unlink(config_file)
return None
# This usually happens only once on a fresh system, SSH keys need to be
# freshly generted, one per every system!
if not os.path.isfile(key_rsa):
syslog(LOG_INFO, 'SSH RSA host key not found, generating new key!')
call(f'ssh-keygen -q -N "" -t rsa -f {key_rsa}')
if not os.path.isfile(key_dsa):
syslog(LOG_INFO, 'SSH DSA host key not found, generating new key!')
call(f'ssh-keygen -q -N "" -t dsa -f {key_dsa}')
if not os.path.isfile(key_ed25519):
syslog(LOG_INFO, 'SSH ed25519 host key not found, generating new key!')
call(f'ssh-keygen -q -N "" -t ed25519 -f {key_ed25519}')
if 'trusted_user_ca_key' in ssh:
ca_key_name = ssh['trusted_user_ca_key']['ca_certificate']
pki_ca_cert = ssh['pki']['ca'][ca_key_name]
loaded_ca_cert = load_certificate(pki_ca_cert['certificate'])
loaded_ca_certs = {
load_certificate(c['certificate'])
for c in ssh['pki']['ca'].values()
if 'certificate' in c
}
ca_full_chain = find_chain(loaded_ca_cert, loaded_ca_certs)
write_file(
trusted_user_ca_key, '\n'.join(encode_certificate(c) for c in ca_full_chain)
)
elif os.path.exists(trusted_user_ca_key):
os.unlink(trusted_user_ca_key)
render(config_file, 'ssh/sshd_config.j2', ssh)
if 'dynamic_protection' in ssh:
render(sshguard_config_file, 'ssh/sshguard_config.j2', ssh)
render(sshguard_whitelist, 'ssh/sshguard_whitelist.j2', ssh)
return None
def apply(ssh):
systemd_service_sshguard = 'sshguard.service'
if not ssh:
# SSH access is removed in the commit
call('systemctl stop ssh@*.service')
call(f'systemctl stop {systemd_service_sshguard}')
return None
if 'dynamic_protection' not in ssh:
call(f'systemctl stop {systemd_service_sshguard}')
else:
call(f'systemctl reload-or-restart {systemd_service_sshguard}')
# we need to restart the service if e.g. the VRF name changed
systemd_action = 'reload-or-restart'
if 'restart_required' in ssh:
# this is only true if something for the VRFs changed, thus we
# stop all VRF services and only restart then new ones
call('systemctl stop ssh@*.service')
systemd_action = 'restart'
for vrf in ssh['vrf']:
call(f'systemctl {systemd_action} ssh@{vrf}.service')
return None
if __name__ == '__main__':
try:
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)
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