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#!/usr/bin/python
# -*- coding: utf-8 -*-
# pylint: disable=fixme, missing-docstring
import subprocess
DOCUMENTATION = '''
---
module: os_firewall_manage_iptables
short_description: This module manages iptables rules for a given chain
author: Jason DeTiberus
requirements: [ ]
'''
EXAMPLES = '''
'''
class IpTablesError(Exception):
def __init__(self, msg, cmd, exit_code, output):
super(IpTablesError, self).__init__(msg)
self.msg = msg
self.cmd = cmd
self.exit_code = exit_code
self.output = output
class IpTablesAddRuleError(IpTablesError):
pass
class IpTablesRemoveRuleError(IpTablesError):
def __init__(self, chain, msg, cmd, exit_code, output): # pylint: disable=too-many-arguments, line-too-long, redefined-outer-name
super(IpTablesRemoveRuleError, self).__init__(msg, cmd, exit_code,
output)
self.chain = chain
class IpTablesSaveError(IpTablesError):
pass
class IpTablesCreateChainError(IpTablesError):
def __init__(self, chain, msg, cmd, exit_code, output): # pylint: disable=too-many-arguments, line-too-long, redefined-outer-name
super(IpTablesCreateChainError, self).__init__(msg, cmd, exit_code,
output)
self.chain = chain
class IpTablesCreateJumpRuleError(IpTablesError):
def __init__(self, chain, msg, cmd, exit_code, output): # pylint: disable=too-many-arguments, line-too-long, redefined-outer-name
super(IpTablesCreateJumpRuleError, self).__init__(msg, cmd, exit_code,
output)
self.chain = chain
# TODO: implement rollbacks for any events that were successful and an
# exception was thrown later. For example, when the chain is created
# successfully, but the add/remove rule fails.
class IpTablesManager(object): # pylint: disable=too-many-instance-attributes
def __init__(self, module):
self.module = module
self.ip_version = module.params['ip_version']
self.check_mode = module.check_mode
self.chain = module.params['chain']
self.create_jump_rule = module.params['create_jump_rule']
self.jump_rule_chain = module.params['jump_rule_chain']
self.cmd = self.gen_cmd()
self.save_cmd = self.gen_save_cmd()
self.output = []
self.changed = False
def save(self):
try:
self.output.append(subprocess.check_output(self.save_cmd, stderr=subprocess.STDOUT))
except subprocess.CalledProcessError as ex:
raise IpTablesSaveError(
msg="Failed to save iptables rules",
cmd=ex.cmd, exit_code=ex.returncode, output=ex.output)
def verify_chain(self):
if not self.chain_exists():
self.create_chain()
if self.create_jump_rule and not self.jump_rule_exists():
self.create_jump()
def add_rule(self, port, proto):
rule = self.gen_rule(port, proto)
if not self.rule_exists(rule):
self.verify_chain()
if self.check_mode:
self.changed = True
self.output.append("Create rule for %s %s" % (proto, port))
else:
cmd = self.cmd + ['-A'] + rule
try:
self.output.append(subprocess.check_output(cmd))
self.changed = True
self.save()
except subprocess.CalledProcessError as ex:
raise IpTablesCreateChainError(
chain=self.chain,
msg="Failed to create rule for "
"%s %s" % (proto, port),
cmd=ex.cmd, exit_code=ex.returncode,
output=ex.output)
def remove_rule(self, port, proto):
rule = self.gen_rule(port, proto)
if self.rule_exists(rule):
if self.check_mode:
self.changed = True
self.output.append("Remove rule for %s %s" % (proto, port))
else:
cmd = self.cmd + ['-D'] + rule
try:
self.output.append(subprocess.check_output(cmd))
self.changed = True
self.save()
except subprocess.CalledProcessError as ex:
raise IpTablesRemoveRuleError(
chain=self.chain,
msg="Failed to remove rule for %s %s" % (proto, port),
cmd=ex.cmd, exit_code=ex.returncode, output=ex.output)
def rule_exists(self, rule):
check_cmd = self.cmd + ['-C'] + rule
return True if subprocess.call(check_cmd) == 0 else False
@staticmethod
def port_as_argument(port):
if isinstance(port, int):
return str(port)
if isinstance(port, basestring): # noqa: F405
return port.replace('-', ":")
return port
def gen_rule(self, port, proto):
return [self.chain, '-p', proto, '-m', 'state', '--state', 'NEW',
'-m', proto, '--dport', IpTablesManager.port_as_argument(port), '-j', 'ACCEPT']
def create_jump(self):
if self.check_mode:
self.changed = True
self.output.append("Create jump rule for chain %s" % self.chain)
else:
try:
cmd = self.cmd + ['-L', self.jump_rule_chain, '--line-numbers']
output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
# break the input rules into rows and columns
input_rules = [s.split() for s in to_native(output).split('\n')]
# Find the last numbered rule
last_rule_num = None
last_rule_target = None
for rule in input_rules[:-1]:
if rule:
try:
last_rule_num = int(rule[0])
except ValueError:
continue
last_rule_target = rule[1]
# Naively assume that if the last row is a REJECT or DROP rule,
# then we can insert our rule right before it, otherwise we
# assume that we can just append the rule.
if (last_rule_num and last_rule_target and last_rule_target in ['REJECT', 'DROP']):
# insert rule
cmd = self.cmd + ['-I', self.jump_rule_chain,
str(last_rule_num)]
else:
# append rule
cmd = self.cmd + ['-A', self.jump_rule_chain]
cmd += ['-j', self.chain]
output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
self.changed = True
self.output.append(output)
self.save()
except subprocess.CalledProcessError as ex:
if '--line-numbers' in ex.cmd:
raise IpTablesCreateJumpRuleError(
chain=self.chain,
msg=("Failed to query existing " +
self.jump_rule_chain +
" rules to determine jump rule location"),
cmd=ex.cmd, exit_code=ex.returncode,
output=ex.output)
else:
raise IpTablesCreateJumpRuleError(
chain=self.chain,
msg=("Failed to create jump rule for chain " +
self.chain),
cmd=ex.cmd, exit_code=ex.returncode,
output=ex.output)
def create_chain(self):
if self.check_mode:
self.changed = True
self.output.append("Create chain %s" % self.chain)
else:
try:
cmd = self.cmd + ['-N', self.chain]
self.output.append(subprocess.check_output(cmd, stderr=subprocess.STDOUT))
self.changed = True
self.output.append("Successfully created chain %s" %
self.chain)
self.save()
except subprocess.CalledProcessError as ex:
raise IpTablesCreateChainError(
chain=self.chain,
msg="Failed to create chain: %s" % self.chain,
cmd=ex.cmd, exit_code=ex.returncode, output=ex.output
)
def jump_rule_exists(self):
cmd = self.cmd + ['-C', self.jump_rule_chain, '-j', self.chain]
return True if subprocess.call(cmd) == 0 else False
def chain_exists(self):
cmd = self.cmd + ['-L', self.chain]
return True if subprocess.call(cmd) == 0 else False
def gen_cmd(self):
cmd = 'iptables' if self.ip_version == 'ipv4' else 'ip6tables'
# Include -w (wait for xtables lock) in default arguments.
default_args = ['-w']
return ["/usr/sbin/%s" % cmd] + default_args
def gen_save_cmd(self): # pylint: disable=no-self-use
return ['/usr/libexec/iptables/iptables.init', 'save']
def main():
module = AnsibleModule( # noqa: F405
argument_spec=dict(
name=dict(required=True),
action=dict(required=True, choices=['add', 'remove',
'verify_chain']),
chain=dict(required=False, default='OS_FIREWALL_ALLOW'),
create_jump_rule=dict(required=False, type='bool', default=True),
jump_rule_chain=dict(required=False, default='INPUT'),
protocol=dict(required=False, choices=['tcp', 'udp']),
port=dict(required=False, type='str'),
ip_version=dict(required=False, default='ipv4',
choices=['ipv4', 'ipv6']),
),
supports_check_mode=True
)
action = module.params['action']
protocol = module.params['protocol']
port = module.params['port']
if action in ['add', 'remove']:
if not protocol:
error = "protocol is required when action is %s" % action
module.fail_json(msg=error)
if not port:
error = "port is required when action is %s" % action
module.fail_json(msg=error)
iptables_manager = IpTablesManager(module)
try:
if action == 'add':
iptables_manager.add_rule(port, protocol)
elif action == 'remove':
iptables_manager.remove_rule(port, protocol)
elif action == 'verify_chain':
iptables_manager.verify_chain()
except IpTablesError as ex:
module.fail_json(msg=ex.msg)
return module.exit_json(changed=iptables_manager.changed,
output=iptables_manager.output)
# pylint: disable=redefined-builtin, unused-wildcard-import, wildcard-import, wrong-import-position
# import module snippets
from ansible.module_utils.basic import * # noqa: F403,E402
from ansible.module_utils._text import to_native # noqa: E402
if __name__ == '__main__':
main()
|
