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community.general/plugins/modules/system/pamd.py
Alexei Znamensky 325a19d88a
pamd - fixed bug ()
* Fixed bug

- The module was searching back (and forward, in the ``after`` state) for lines that were not comments, assuming it would be a valid rule or an include.

* remove the line, make yamllint happy

* Update changelogs/fragments/1394-pamd-removing-comments.yaml

Co-authored-by: Felix Fontein <felix@fontein.de>

Co-authored-by: Felix Fontein <felix@fontein.de>
2021-01-03 11:38:04 +01:00

866 lines
31 KiB
Python

#!/usr/bin/python
# -*- coding: utf-8 -*-
# Copyright: (c) 2017, Kenneth D. Evensen <kdevensen@gmail.com>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type
DOCUMENTATION = r'''
module: pamd
author:
- Kenneth D. Evensen (@kevensen)
short_description: Manage PAM Modules
description:
- Edit PAM service's type, control, module path and module arguments.
- In order for a PAM rule to be modified, the type, control and
module_path must match an existing rule. See man(5) pam.d for details.
options:
name:
description:
- The name generally refers to the PAM service file to
change, for example system-auth.
type: str
required: true
type:
description:
- The type of the PAM rule being modified.
- The C(type), C(control) and C(module_path) all must match a rule to be modified.
type: str
required: true
choices: [ account, -account, auth, -auth, password, -password, session, -session ]
control:
description:
- The control of the PAM rule being modified.
- This may be a complicated control with brackets. If this is the case, be
sure to put "[bracketed controls]" in quotes.
- The C(type), C(control) and C(module_path) all must match a rule to be modified.
type: str
required: true
module_path:
description:
- The module path of the PAM rule being modified.
- The C(type), C(control) and C(module_path) all must match a rule to be modified.
type: str
required: true
new_type:
description:
- The new type to assign to the new rule.
type: str
choices: [ account, -account, auth, -auth, password, -password, session, -session ]
new_control:
description:
- The new control to assign to the new rule.
type: str
new_module_path:
description:
- The new module path to be assigned to the new rule.
type: str
module_arguments:
description:
- When state is C(updated), the module_arguments will replace existing module_arguments.
- When state is C(args_absent) args matching those listed in module_arguments will be removed.
- When state is C(args_present) any args listed in module_arguments are added if
missing from the existing rule.
- Furthermore, if the module argument takes a value denoted by C(=),
the value will be changed to that specified in module_arguments.
type: list
elements: str
state:
description:
- The default of C(updated) will modify an existing rule if type,
control and module_path all match an existing rule.
- With C(before), the new rule will be inserted before a rule matching type,
control and module_path.
- Similarly, with C(after), the new rule will be inserted after an existing rulematching type,
control and module_path.
- With either C(before) or C(after) new_type, new_control, and new_module_path must all be specified.
- If state is C(args_absent) or C(args_present), new_type, new_control, and new_module_path will be ignored.
- State C(absent) will remove the rule. The 'absent' state was added in Ansible 2.4.
type: str
choices: [ absent, before, after, args_absent, args_present, updated ]
default: updated
path:
description:
- This is the path to the PAM service files.
type: path
default: /etc/pam.d
backup:
description:
- Create a backup file including the timestamp information so you can
get the original file back if you somehow clobbered it incorrectly.
type: bool
default: no
'''
EXAMPLES = r'''
- name: Update pamd rule's control in /etc/pam.d/system-auth
community.general.pamd:
name: system-auth
type: auth
control: required
module_path: pam_faillock.so
new_control: sufficient
- name: Update pamd rule's complex control in /etc/pam.d/system-auth
community.general.pamd:
name: system-auth
type: session
control: '[success=1 default=ignore]'
module_path: pam_succeed_if.so
new_control: '[success=2 default=ignore]'
- name: Insert a new rule before an existing rule
community.general.pamd:
name: system-auth
type: auth
control: required
module_path: pam_faillock.so
new_type: auth
new_control: sufficient
new_module_path: pam_faillock.so
state: before
- name: Insert a new rule pam_wheel.so with argument 'use_uid' after an \
existing rule pam_rootok.so
community.general.pamd:
name: su
type: auth
control: sufficient
module_path: pam_rootok.so
new_type: auth
new_control: required
new_module_path: pam_wheel.so
module_arguments: 'use_uid'
state: after
- name: Remove module arguments from an existing rule
community.general.pamd:
name: system-auth
type: auth
control: required
module_path: pam_faillock.so
module_arguments: ''
state: updated
- name: Replace all module arguments in an existing rule
community.general.pamd:
name: system-auth
type: auth
control: required
module_path: pam_faillock.so
module_arguments: 'preauth
silent
deny=3
unlock_time=604800
fail_interval=900'
state: updated
- name: Remove specific arguments from a rule
community.general.pamd:
name: system-auth
type: session
control: '[success=1 default=ignore]'
module_path: pam_succeed_if.so
module_arguments: crond,quiet
state: args_absent
- name: Ensure specific arguments are present in a rule
community.general.pamd:
name: system-auth
type: session
control: '[success=1 default=ignore]'
module_path: pam_succeed_if.so
module_arguments: crond,quiet
state: args_present
- name: Ensure specific arguments are present in a rule (alternative)
community.general.pamd:
name: system-auth
type: session
control: '[success=1 default=ignore]'
module_path: pam_succeed_if.so
module_arguments:
- crond
- quiet
state: args_present
- name: Module arguments requiring commas must be listed as a Yaml list
community.general.pamd:
name: special-module
type: account
control: required
module_path: pam_access.so
module_arguments:
- listsep=,
state: args_present
- name: Update specific argument value in a rule
community.general.pamd:
name: system-auth
type: auth
control: required
module_path: pam_faillock.so
module_arguments: 'fail_interval=300'
state: args_present
- name: Add pam common-auth rule for duo
community.general.pamd:
name: common-auth
new_type: auth
new_control: '[success=1 default=ignore]'
new_module_path: '/lib64/security/pam_duo.so'
state: after
type: auth
module_path: pam_sss.so
control: 'requisite'
'''
RETURN = r'''
change_count:
description: How many rules were changed.
type: int
sample: 1
returned: success
new_rule:
description: The changes to the rule. This was available in Ansible 2.4 and Ansible 2.5. It was removed in Ansible 2.6.
type: str
sample: None None None sha512 shadow try_first_pass use_authtok
returned: success
updated_rule_(n):
description: The rule(s) that was/were changed. This is only available in
Ansible 2.4 and was removed in Ansible 2.5.
type: str
sample:
- password sufficient pam_unix.so sha512 shadow try_first_pass
use_authtok
returned: success
action:
description:
- "That action that was taken and is one of: update_rule,
insert_before_rule, insert_after_rule, args_present, args_absent,
absent. This was available in Ansible 2.4 and removed in Ansible 2.8"
returned: always
type: str
sample: "update_rule"
dest:
description:
- "Path to pam.d service that was changed. This is only available in
Ansible 2.3 and was removed in Ansible 2.4."
returned: success
type: str
sample: "/etc/pam.d/system-auth"
backupdest:
description:
- "The file name of the backup file, if created."
returned: success
type: str
...
'''
from ansible.module_utils.basic import AnsibleModule
import os
import re
from tempfile import NamedTemporaryFile
from datetime import datetime
RULE_REGEX = re.compile(r"""(?P<rule_type>-?(?:auth|account|session|password))\s+
(?P<control>\[.*\]|\S*)\s+
(?P<path>\S*)\s*
(?P<args>.*)\s*""", re.X)
RULE_ARG_REGEX = re.compile(r"""(\[.*\]|\S*)""")
VALID_TYPES = ['account', '-account', 'auth', '-auth', 'password', '-password', 'session', '-session']
class PamdLine(object):
def __init__(self, line):
self.line = line
self.prev = None
self.next = None
@property
def is_valid(self):
if self.line.strip() == '':
return True
return False
def validate(self):
if not self.is_valid:
return False, "Rule is not valid " + self.line
return True, "Rule is valid " + self.line
# Method to check if a rule matches the type, control and path.
def matches(self, rule_type, rule_control, rule_path, rule_args=None):
return False
def __str__(self):
return str(self.line)
class PamdEmptyLine(PamdLine):
pass
class PamdComment(PamdLine):
def __init__(self, line):
super(PamdComment, self).__init__(line)
@property
def is_valid(self):
if self.line.startswith('#'):
return True
return False
class PamdInclude(PamdLine):
def __init__(self, line):
super(PamdInclude, self).__init__(line)
@property
def is_valid(self):
if self.line.startswith('@include'):
return True
return False
class PamdRule(PamdLine):
valid_simple_controls = ['required', 'requisite', 'sufficient', 'optional', 'include', 'substack', 'definitive']
valid_control_values = ['success', 'open_err', 'symbol_err', 'service_err', 'system_err', 'buf_err',
'perm_denied', 'auth_err', 'cred_insufficient', 'authinfo_unavail', 'user_unknown',
'maxtries', 'new_authtok_reqd', 'acct_expired', 'session_err', 'cred_unavail',
'cred_expired', 'cred_err', 'no_module_data', 'conv_err', 'authtok_err',
'authtok_recover_err', 'authtok_lock_busy', 'authtok_disable_aging', 'try_again',
'ignore', 'abort', 'authtok_expired', 'module_unknown', 'bad_item', 'conv_again',
'incomplete', 'default']
valid_control_actions = ['ignore', 'bad', 'die', 'ok', 'done', 'reset']
def __init__(self, rule_type, rule_control, rule_path, rule_args=None):
self.prev = None
self.next = None
self._control = None
self._args = None
self.rule_type = rule_type
self.rule_control = rule_control
self.rule_path = rule_path
self.rule_args = rule_args
# Method to check if a rule matches the type, control and path.
def matches(self, rule_type, rule_control, rule_path, rule_args=None):
if (rule_type == self.rule_type and
rule_control == self.rule_control and
rule_path == self.rule_path):
return True
return False
@classmethod
def rule_from_string(cls, line):
rule_match = RULE_REGEX.search(line)
rule_args = parse_module_arguments(rule_match.group('args'))
return cls(rule_match.group('rule_type'), rule_match.group('control'), rule_match.group('path'), rule_args)
def __str__(self):
if self.rule_args:
return '{0: <11}{1} {2} {3}'.format(self.rule_type, self.rule_control, self.rule_path, ' '.join(self.rule_args))
return '{0: <11}{1} {2}'.format(self.rule_type, self.rule_control, self.rule_path)
@property
def rule_control(self):
if isinstance(self._control, list):
return '[' + ' '.join(self._control) + ']'
return self._control
@rule_control.setter
def rule_control(self, control):
if control.startswith('['):
control = control.replace(' = ', '=').replace('[', '').replace(']', '')
self._control = control.split(' ')
else:
self._control = control
@property
def rule_args(self):
if not self._args:
return []
return self._args
@rule_args.setter
def rule_args(self, args):
self._args = parse_module_arguments(args)
@property
def line(self):
return str(self)
@classmethod
def is_action_unsigned_int(cls, string_num):
number = 0
try:
number = int(string_num)
except ValueError:
return False
if number >= 0:
return True
return False
@property
def is_valid(self):
return self.validate()[0]
def validate(self):
# Validate the rule type
if self.rule_type not in VALID_TYPES:
return False, "Rule type, " + self.rule_type + ", is not valid in rule " + self.line
# Validate the rule control
if isinstance(self._control, str) and self.rule_control not in PamdRule.valid_simple_controls:
return False, "Rule control, " + self.rule_control + ", is not valid in rule " + self.line
elif isinstance(self._control, list):
for control in self._control:
value, action = control.split("=")
if value not in PamdRule.valid_control_values:
return False, "Rule control value, " + value + ", is not valid in rule " + self.line
if action not in PamdRule.valid_control_actions and not PamdRule.is_action_unsigned_int(action):
return False, "Rule control action, " + action + ", is not valid in rule " + self.line
# TODO: Validate path
return True, "Rule is valid " + self.line
# PamdService encapsulates an entire service and contains one or more rules. It seems the best way is to do this
# as a doubly linked list.
class PamdService(object):
def __init__(self, content):
self._head = None
self._tail = None
for line in content.splitlines():
if line.lstrip().startswith('#'):
pamd_line = PamdComment(line)
elif line.lstrip().startswith('@include'):
pamd_line = PamdInclude(line)
elif line.strip() == '':
pamd_line = PamdEmptyLine(line)
else:
pamd_line = PamdRule.rule_from_string(line)
self.append(pamd_line)
def append(self, pamd_line):
if self._head is None:
self._head = self._tail = pamd_line
else:
pamd_line.prev = self._tail
pamd_line.next = None
self._tail.next = pamd_line
self._tail = pamd_line
def remove(self, rule_type, rule_control, rule_path):
current_line = self._head
changed = 0
while current_line is not None:
if current_line.matches(rule_type, rule_control, rule_path):
if current_line.prev is not None:
current_line.prev.next = current_line.next
if current_line.next is not None:
current_line.next.prev = current_line.prev
else:
self._head = current_line.next
current_line.next.prev = None
changed += 1
current_line = current_line.next
return changed
def get(self, rule_type, rule_control, rule_path):
lines = []
current_line = self._head
while current_line is not None:
if isinstance(current_line, PamdRule) and current_line.matches(rule_type, rule_control, rule_path):
lines.append(current_line)
current_line = current_line.next
return lines
def has_rule(self, rule_type, rule_control, rule_path):
if self.get(rule_type, rule_control, rule_path):
return True
return False
def update_rule(self, rule_type, rule_control, rule_path,
new_type=None, new_control=None, new_path=None, new_args=None):
# Get a list of rules we want to change
rules_to_find = self.get(rule_type, rule_control, rule_path)
new_args = parse_module_arguments(new_args)
changes = 0
for current_rule in rules_to_find:
rule_changed = False
if new_type:
if(current_rule.rule_type != new_type):
rule_changed = True
current_rule.rule_type = new_type
if new_control:
if(current_rule.rule_control != new_control):
rule_changed = True
current_rule.rule_control = new_control
if new_path:
if(current_rule.rule_path != new_path):
rule_changed = True
current_rule.rule_path = new_path
if new_args:
if(current_rule.rule_args != new_args):
rule_changed = True
current_rule.rule_args = new_args
if rule_changed:
changes += 1
return changes
def insert_before(self, rule_type, rule_control, rule_path,
new_type=None, new_control=None, new_path=None, new_args=None):
# Get a list of rules we want to change
rules_to_find = self.get(rule_type, rule_control, rule_path)
changes = 0
# There are two cases to consider.
# 1. The new rule doesn't exist before the existing rule
# 2. The new rule exists
for current_rule in rules_to_find:
# Create a new rule
new_rule = PamdRule(new_type, new_control, new_path, new_args)
# First we'll get the previous rule.
previous_rule = current_rule.prev
# Next we may have to loop backwards if the previous line is a comment. If it
# is, we'll get the previous "rule's" previous.
while previous_rule is not None and isinstance(previous_rule, (PamdComment, PamdEmptyLine)):
previous_rule = previous_rule.prev
# Next we'll see if the previous rule matches what we are trying to insert.
if previous_rule is not None and not previous_rule.matches(new_type, new_control, new_path):
# First set the original previous rule's next to the new_rule
previous_rule.next = new_rule
# Second, set the new_rule's previous to the original previous
new_rule.prev = previous_rule
# Third, set the new rule's next to the current rule
new_rule.next = current_rule
# Fourth, set the current rule's previous to the new_rule
current_rule.prev = new_rule
changes += 1
# Handle the case where it is the first rule in the list.
elif previous_rule is None:
# This is the case where the current rule is not only the first rule
# but the first line as well. So we set the head to the new rule
if current_rule.prev is None:
self._head = new_rule
# This case would occur if the previous line was a comment.
else:
current_rule.prev.next = new_rule
new_rule.prev = current_rule.prev
new_rule.next = current_rule
current_rule.prev = new_rule
changes += 1
return changes
def insert_after(self, rule_type, rule_control, rule_path,
new_type=None, new_control=None, new_path=None, new_args=None):
# Get a list of rules we want to change
rules_to_find = self.get(rule_type, rule_control, rule_path)
changes = 0
# There are two cases to consider.
# 1. The new rule doesn't exist after the existing rule
# 2. The new rule exists
for current_rule in rules_to_find:
# First we'll get the next rule.
next_rule = current_rule.next
# Next we may have to loop forwards if the next line is a comment. If it
# is, we'll get the next "rule's" next.
while next_rule is not None and isinstance(next_rule, (PamdComment, PamdEmptyLine)):
next_rule = next_rule.next
# First we create a new rule
new_rule = PamdRule(new_type, new_control, new_path, new_args)
if next_rule is not None and not next_rule.matches(new_type, new_control, new_path):
# If the previous rule doesn't match we'll insert our new rule.
# Second set the original next rule's previous to the new_rule
next_rule.prev = new_rule
# Third, set the new_rule's next to the original next rule
new_rule.next = next_rule
# Fourth, set the new rule's previous to the current rule
new_rule.prev = current_rule
# Fifth, set the current rule's next to the new_rule
current_rule.next = new_rule
changes += 1
# This is the case where the current_rule is the last in the list
elif next_rule is None:
new_rule.prev = self._tail
new_rule.next = None
self._tail.next = new_rule
self._tail = new_rule
current_rule.next = new_rule
changes += 1
return changes
def add_module_arguments(self, rule_type, rule_control, rule_path, args_to_add):
# Get a list of rules we want to change
rules_to_find = self.get(rule_type, rule_control, rule_path)
args_to_add = parse_module_arguments(args_to_add)
changes = 0
for current_rule in rules_to_find:
rule_changed = False
# create some structures to evaluate the situation
simple_new_args = set()
key_value_new_args = dict()
for arg in args_to_add:
if arg.startswith("["):
continue
elif "=" in arg:
key, value = arg.split("=")
key_value_new_args[key] = value
else:
simple_new_args.add(arg)
key_value_new_args_set = set(key_value_new_args)
simple_current_args = set()
key_value_current_args = dict()
for arg in current_rule.rule_args:
if arg.startswith("["):
continue
elif "=" in arg:
key, value = arg.split("=")
key_value_current_args[key] = value
else:
simple_current_args.add(arg)
key_value_current_args_set = set(key_value_current_args)
new_args_to_add = list()
# Handle new simple arguments
if simple_new_args.difference(simple_current_args):
for arg in simple_new_args.difference(simple_current_args):
new_args_to_add.append(arg)
# Handle new key value arguments
if key_value_new_args_set.difference(key_value_current_args_set):
for key in key_value_new_args_set.difference(key_value_current_args_set):
new_args_to_add.append(key + '=' + key_value_new_args[key])
if new_args_to_add:
current_rule.rule_args += new_args_to_add
rule_changed = True
# Handle existing key value arguments when value is not equal
if key_value_new_args_set.intersection(key_value_current_args_set):
for key in key_value_new_args_set.intersection(key_value_current_args_set):
if key_value_current_args[key] != key_value_new_args[key]:
arg_index = current_rule.rule_args.index(key + '=' + key_value_current_args[key])
current_rule.rule_args[arg_index] = str(key + '=' + key_value_new_args[key])
rule_changed = True
if rule_changed:
changes += 1
return changes
def remove_module_arguments(self, rule_type, rule_control, rule_path, args_to_remove):
# Get a list of rules we want to change
rules_to_find = self.get(rule_type, rule_control, rule_path)
args_to_remove = parse_module_arguments(args_to_remove)
changes = 0
for current_rule in rules_to_find:
if not args_to_remove:
args_to_remove = []
# Let's check to see if there are any args to remove by finding the intersection
# of the rule's current args and the args_to_remove lists
if not list(set(current_rule.rule_args) & set(args_to_remove)):
continue
# There are args to remove, so we create a list of new_args absent the args
# to remove.
current_rule.rule_args = [arg for arg in current_rule.rule_args if arg not in args_to_remove]
changes += 1
return changes
def validate(self):
current_line = self._head
while current_line is not None:
if not current_line.validate()[0]:
return current_line.validate()
current_line = current_line.next
return True, "Module is valid"
def __str__(self):
lines = []
current_line = self._head
while current_line is not None:
lines.append(str(current_line))
current_line = current_line.next
if lines[1].startswith("# Updated by Ansible"):
lines.pop(1)
lines.insert(1, "# Updated by Ansible - " + datetime.now().isoformat())
return '\n'.join(lines) + '\n'
def parse_module_arguments(module_arguments):
# Return empty list if we have no args to parse
if not module_arguments:
return []
elif isinstance(module_arguments, list) and len(module_arguments) == 1 and not module_arguments[0]:
return []
if not isinstance(module_arguments, list):
module_arguments = [module_arguments]
parsed_args = list()
for arg in module_arguments:
for item in filter(None, RULE_ARG_REGEX.findall(arg)):
if not item.startswith("["):
re.sub("\\s*=\\s*", "=", item)
parsed_args.append(item)
return parsed_args
def main():
module = AnsibleModule(
argument_spec=dict(
name=dict(type='str', required=True),
type=dict(type='str', required=True, choices=VALID_TYPES),
control=dict(type='str', required=True),
module_path=dict(type='str', required=True),
new_type=dict(type='str', choices=VALID_TYPES),
new_control=dict(type='str'),
new_module_path=dict(type='str'),
module_arguments=dict(type='list', elements='str'),
state=dict(type='str', default='updated', choices=['absent', 'after', 'args_absent', 'args_present', 'before', 'updated']),
path=dict(type='path', default='/etc/pam.d'),
backup=dict(type='bool', default=False),
),
supports_check_mode=True,
required_if=[
("state", "args_present", ["module_arguments"]),
("state", "args_absent", ["module_arguments"]),
("state", "before", ["new_control", "new_type", "new_module_path"]),
("state", "after", ["new_control", "new_type", "new_module_path"]),
],
)
content = str()
fname = os.path.join(module.params["path"], module.params["name"])
# Open the file and read the content or fail
try:
with open(fname, 'r') as service_file_obj:
content = service_file_obj.read()
except IOError as e:
# If unable to read the file, fail out
module.fail_json(msg='Unable to open/read PAM module file %s with error %s.' % (fname, str(e)))
# Assuming we didn't fail, create the service
service = PamdService(content)
# Set the action
action = module.params['state']
changes = 0
# Take action
if action == 'updated':
changes = service.update_rule(module.params['type'], module.params['control'], module.params['module_path'],
module.params['new_type'], module.params['new_control'], module.params['new_module_path'],
module.params['module_arguments'])
elif action == 'before':
changes = service.insert_before(module.params['type'], module.params['control'], module.params['module_path'],
module.params['new_type'], module.params['new_control'], module.params['new_module_path'],
module.params['module_arguments'])
elif action == 'after':
changes = service.insert_after(module.params['type'], module.params['control'], module.params['module_path'],
module.params['new_type'], module.params['new_control'], module.params['new_module_path'],
module.params['module_arguments'])
elif action == 'args_absent':
changes = service.remove_module_arguments(module.params['type'], module.params['control'], module.params['module_path'],
module.params['module_arguments'])
elif action == 'args_present':
if [arg for arg in parse_module_arguments(module.params['module_arguments']) if arg.startswith("[")]:
module.fail_json(msg="Unable to process bracketed '[' complex arguments with 'args_present'. Please use 'updated'.")
changes = service.add_module_arguments(module.params['type'], module.params['control'], module.params['module_path'],
module.params['module_arguments'])
elif action == 'absent':
changes = service.remove(module.params['type'], module.params['control'], module.params['module_path'])
valid, msg = service.validate()
# If the module is not valid (meaning one of the rules is invalid), we will fail
if not valid:
module.fail_json(msg=msg)
result = dict(
changed=(changes > 0),
change_count=changes,
backupdest='',
)
# If not check mode and something changed, backup the original if necessary then write out the file or fail
if not module.check_mode and result['changed']:
# First, create a backup if desired.
if module.params['backup']:
result['backupdest'] = module.backup_local(fname)
try:
temp_file = NamedTemporaryFile(mode='w', dir=module.tmpdir, delete=False)
with open(temp_file.name, 'w') as fd:
fd.write(str(service))
except IOError:
module.fail_json(msg='Unable to create temporary \
file %s' % temp_file)
module.atomic_move(temp_file.name, os.path.realpath(fname))
module.exit_json(**result)
if __name__ == '__main__':
main()