Mini Shell

# coding=utf-8

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2018 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

import os
import pwd
import grp
import re
import subprocess
import tempfile
from stat import S_IRUSR, S_IRGRP


class NoSuchUser(Exception):
    def __init__(self, user):
        Exception.__init__(self, f'No such user ({user})')


class NoSuchGroup(Exception):
    def __init__(self, group):
        Exception.__init__(self, f'No such group ({group})')


class UnableToReadFile(Exception):
    def __init__(self):
        Exception.__init__(self, 'Cannot read sudoers file')


class UnableToWriteFile(Exception):
    def __init__(self):
        Exception.__init__(self, 'Cannot modify sudoers file')


SUDOERS_FILE = '/etc/sudoers'
ALIAS_LVECTL_CMDS = ["/bin/ps", "/bin/grep", "/sbin/service", "/usr/bin/getcontrolpaneluserspackages",
                     "/usr/sbin/lvectl", "/usr/local/directadmin/plugins/new_lvemanager/admin/GetDomains",
                     "/usr/share/l.v.e-manager/utils/cloudlinux-cli.py"]

ALIAS_LVECTL_USER_CMDS = ["/usr/share/l.v.e-manager/utils/cloudlinux-cli-user.py"]

ALIAS_SELECTOR_CMDS = ["/usr/bin/cl-selector", "/usr/bin/piniset", "/usr/sbin/lveps", "/usr/bin/selectorctl"]

DEFAULTS_REQUIRETTY = 'Defaults:%s !requiretty'
# Patterns for group
GROUP_LVECTL_SELECTOR = '%%%s ALL=NOPASSWD: LVECTL_CMDS, SELECTOR_CMDS'
GROUP_DEFAULTS_REQUIRETTY = 'Defaults:%%%s !requiretty'


class Clsudo:
    """
    Adds CloudLinux users to sudoers file
    """
    filepath = None
    sudoers_list = []
    has_action = False
    has_group_action = False
    has_alias = False
    has_user_alias = False
    has_rights = False
    has_user_rights = False
    has_selector_alias = False
    has_selector_rights = False
    has_cagefs_alias = False
    has_cagefs_rights = False

    @staticmethod
    def add_user(user, sudoers_file=SUDOERS_FILE):
        """
        Adds username to sudoers file (for lvemanager)
        """
        # Update command lists for lvemanager
        Clsudo.update_commands_list(sudoers_file)
        Clsudo._check_user(user)
        Clsudo._get_contents(user)

        if not Clsudo.has_alias:
            Clsudo.sudoers_list.append('Cmnd_Alias LVECTL_CMDS = ' + ", ".join(ALIAS_LVECTL_CMDS))
        if not Clsudo.has_user_alias:
            Clsudo.sudoers_list.append('Cmnd_Alias LVECTL_USER_CMDS = ' + ", ".join(ALIAS_LVECTL_USER_CMDS))
        if not Clsudo.has_selector_alias:
            Clsudo.sudoers_list.append('Cmnd_Alias SELECTOR_CMDS = ' + ", ".join(ALIAS_SELECTOR_CMDS))
        if not Clsudo.has_rights:
            Clsudo.sudoers_list.append(f'{user} ALL=NOPASSWD: LVECTL_CMDS')
        if not Clsudo.has_user_rights:
            Clsudo.sudoers_list.append(f'{user} ALL=(ALL) NOPASSWD: LVECTL_USER_CMDS')
        if not Clsudo.has_selector_rights:
            Clsudo.sudoers_list.append(f'{user} ALL=NOPASSWD: SELECTOR_CMDS')
        if not Clsudo.has_action:
            Clsudo.sudoers_list.append(DEFAULTS_REQUIRETTY % (user,))
        Clsudo._write_contents()

    @staticmethod
    def add_cagefs_user(user, sudoers_file=SUDOERS_FILE):
        """
        Adds username to sudoers file (for cagefs)
        """
        Clsudo.filepath = sudoers_file
        Clsudo._check_user(user)
        Clsudo._get_contents(user)
        if not Clsudo.has_cagefs_alias:
            Clsudo.sudoers_list.append('Cmnd_Alias CAGEFS_CMDS = /usr/sbin/cagefsctl, '
                                       '/bin/ps, /bin/grep, /sbin/service')
        if not Clsudo.has_cagefs_rights:
            Clsudo.sudoers_list.append(f'{user} ALL=NOPASSWD: CAGEFS_CMDS')
        if not Clsudo.has_action:
            Clsudo.sudoers_list.append(DEFAULTS_REQUIRETTY % (user,))
        Clsudo._write_contents()

    @staticmethod
    def add_lvemanager_group(group_name, sudoers_file=SUDOERS_FILE):
        """
        Adds group to sudoers file, grants access to LVE Manager
        """
        # Update command lists for lvemanager
        Clsudo.update_commands_list(sudoers_file)
        Clsudo._check_group(group_name)
        Clsudo._get_contents_group(group_name)
        if not Clsudo.has_alias:
            Clsudo.sudoers_list.append('Cmnd_Alias LVECTL_CMDS = ' + ", ".join(ALIAS_LVECTL_CMDS))
        if not Clsudo.has_selector_alias:
            Clsudo.sudoers_list.append('Cmnd_Alias SELECTOR_CMDS = ' + ", ".join(ALIAS_SELECTOR_CMDS))
        if not Clsudo.has_action:
            Clsudo.sudoers_list.append(GROUP_LVECTL_SELECTOR % (group_name,))
        if not Clsudo.has_group_action:
            Clsudo.sudoers_list.append(GROUP_DEFAULTS_REQUIRETTY % (group_name,))
        # writes file
        Clsudo._write_contents()

    @staticmethod
    def remove_user(user, sudoers_file=SUDOERS_FILE):
        """
         Removes username from sudoers file
        """
        Clsudo.filepath = sudoers_file
        try:
            with open(Clsudo.filepath, encoding='utf-8') as f:
                Clsudo.sudoers_list = f.read().splitlines()
            idx = 0
            removed = False
            while idx < len(Clsudo.sudoers_list):
                line = Clsudo.sudoers_list[idx]
                if ((f'{user} ALL=NOPASSWD:') in line) or ((DEFAULTS_REQUIRETTY % (user,)) in line):
                    Clsudo.sudoers_list.remove(line)
                    removed = True
                    continue
                idx += 1
            if removed:
                Clsudo._write_contents()
        except (IOError, OSError) as e:
            raise UnableToReadFile() from e

    @staticmethod
    def update_user(user, sudoers_file=SUDOERS_FILE):
        """
        updates username in sudoers file
        :param user: username for caching
        :param sudoers_file: path to /etc/sudoers (only for tests)
        :return: None
        """
        # Update command lists
        Clsudo.update_commands_list(sudoers_file)
        # For backward compatibility
        # Check user presence in system
        Clsudo._check_user(user)
        Clsudo._get_contents(user)

    @staticmethod
    def update_commands_list(sudoers_file=SUDOERS_FILE):
        """
        Update command lists for lvemanager plugin
        If any required command absent in file, add it
        :param sudoers_file: path to /etc/sudoers
        :return: None
        """
        # Read /etc/sudoers
        Clsudo.filepath = sudoers_file
        Clsudo.temp_dir = os.path.dirname(Clsudo.filepath)
        Clsudo._read_sudoers()
        cmnd_dict = {"Cmnd_Alias LVECTL_CMDS": ALIAS_LVECTL_CMDS,
                     "Cmnd_Alias SELECTOR_CMDS": ALIAS_SELECTOR_CMDS}
        is_sudoer_change = False
        for idx, command_string in enumerate(Clsudo.sudoers_list):
            for aliase_key, aliase_list in cmnd_dict.items():
                if aliase_key in command_string:
                    command_string = command_string.replace(aliase_key, "").strip()
                    cmnd_list = command_string.split(",")
                    for aliase_cmnd_item in aliase_list:
                        if aliase_cmnd_item not in cmnd_list:
                            is_sudoer_change = True
                            Clsudo.sudoers_list[idx] = f"{aliase_key} = {', '.join(aliase_list)}"
                            break
            if is_sudoer_change:
                Clsudo._write_contents()

    @staticmethod
    def _check_user(user):
        """
        Checks passwd database for username presence
        @param user: string
        """
        try:
            pwd.getpwnam(user)
        except KeyError as e:
            raise NoSuchUser(user) from e

    @staticmethod
    def _check_group(group_name):
        """
        Checks grp database for group_name presence
        @param group_name: string
        """
        try:
            grp.getgrnam(group_name)
        except KeyError as e:
            raise NoSuchGroup(group_name) from e

    @staticmethod
    def _read_sudoers():
        with open(Clsudo.filepath, encoding='utf-8') as f:
            Clsudo.sudoers_list = f.read().splitlines()

    @staticmethod
    def _get_contents(user):
        """
        Reads file into list of strings
        @param user: string
        """
        # Clear all status flags
        Clsudo.has_action = False
        Clsudo.has_group_action = False
        Clsudo.has_alias = False
        Clsudo.has_user_alias = False
        Clsudo.has_rights = False
        Clsudo.has_user_rights = False
        Clsudo.has_selector_alias = False
        Clsudo.has_selector_rights = False
        Clsudo.has_cagefs_alias = False
        Clsudo.has_cagefs_rights = False
        require_tty_pattern = re.compile(rf'Defaults:\s*{user}\s*!requiretty')

        try:
            # Read sudoers file
            Clsudo._read_sudoers()
            for idx, command_string in enumerate(Clsudo.sudoers_list):
                if "Cmnd_Alias LVECTL_CMDS" in command_string:
                    Clsudo.has_alias = True
                    continue
                if "Cmnd_Alias LVECTL_USER_CMDS" in command_string:
                    Clsudo.has_user_alias = True
                    continue
                if "Cmnd_Alias CAGEFS_CMDS" in command_string:
                    Clsudo.has_cagefs_alias = True
                    continue
                if f"{user} ALL=NOPASSWD: LVECTL_CMDS" in command_string:
                    Clsudo.has_rights = True
                    continue
                if f"{user} ALL=(ALL) NOPASSWD: LVECTL_USER_CMDS" in command_string:
                    Clsudo.has_user_rights = True
                    continue
                if f"{user} ALL=NOPASSWD: CAGEFS_CMDS" in command_string:
                    Clsudo.has_cagefs_rights = True
                    continue
                if "requiretty" in command_string:
                    pattern_match = require_tty_pattern.search(command_string)
                    if pattern_match:
                        Clsudo.has_action = True
                    continue
                if "Cmnd_Alias SELECTOR_CMDS" in command_string:
                    if 'piniset' not in command_string:
                        Clsudo.sudoers_list[idx] = command_string.replace(
                            '/usr/bin/cl-selector',
                            '/usr/bin/cl-selector, /usr/bin/piniset',
                        )
                    if 'lveps' not in command_string:
                        Clsudo.sudoers_list[idx] = command_string.replace(
                            '/usr/bin/cl-selector, /usr/bin/piniset',
                            '/usr/bin/cl-selector, /usr/bin/piniset, /usr/sbin/lveps',
                        )
                    Clsudo.has_selector_alias = True
                    continue
                if f"{user} ALL=NOPASSWD: SELECTOR_CMDS" in command_string:
                    Clsudo.has_selector_rights = True
                    continue
        except (IOError, OSError) as e:
            raise UnableToReadFile() from e

    @staticmethod
    def _get_contents_group(group_name):
        """
        Reads file into list of strings
        @param group_name: string
        """
        # Clear all status flags
        Clsudo.has_action = False
        Clsudo.has_group_action = False
        Clsudo.has_alias = False
        Clsudo.has_rights = False
        Clsudo.has_selector_alias = False
        Clsudo.has_selector_rights = False
        Clsudo.has_cagefs_alias = False
        Clsudo.has_cagefs_rights = False
        group_prefix = f"%{group_name}"
        group_action = f"Defaults:%{group_name}"
        group_pattern = re.compile(rf'{group_name}\s*ALL=NOPASSWD:\s*LVECTL_CMDS,\s*SELECTOR_CMDS')

        try:
            # Read sudoers file
            Clsudo._read_sudoers()
            for idx, command_string in enumerate(Clsudo.sudoers_list):
                if "Cmnd_Alias SELECTOR_CMDS" in command_string:
                    if 'piniset' not in command_string:
                        Clsudo.sudoers_list[idx] = command_string.replace(
                            '/usr/bin/cl-selector',
                            '/usr/bin/cl-selector, /usr/bin/piniset',
                        )
                    if 'lveps' not in command_string:
                        Clsudo.sudoers_list[idx] = command_string.replace(
                            '/usr/bin/cl-selector, /usr/bin/piniset',
                            '/usr/bin/cl-selector, /usr/bin/piniset, /usr/sbin/lveps',
                        )
                    Clsudo.has_selector_alias = True
                    continue
                if "Cmnd_Alias LVECTL_CMDS" in command_string:
                    Clsudo.has_alias = True
                    continue
                if "Cmnd_Alias CAGEFS_CMDS" in command_string:
                    Clsudo.has_cagefs_alias = True
                    continue
                if command_string.startswith(group_prefix):
                    pattern_match = group_pattern.search(command_string)
                    if pattern_match:
                        Clsudo.has_action = True
                if command_string.startswith(group_action):
                    Clsudo.has_group_action = True
        except (IOError, OSError) as e:
            raise UnableToReadFile() from e

    @staticmethod
    def _write_contents():
        """
        Writes data to temporary file then checks it and rewrites sudoers file
        """
        try:
            temp_dir = os.path.dirname(Clsudo.filepath)
            temp_prefix = 'lve_sudoers_'
            fd, temp_path = tempfile.mkstemp(prefix=temp_prefix, dir=temp_dir)
            fo = os.fdopen(fd, 'w')
            fo.write('\n'.join(Clsudo.sudoers_list) + '\n')
            fo.close()
            mask = S_IRUSR | S_IRGRP
            os.chmod(temp_path, mask)
            if not Clsudo._is_file_valid(temp_path):
                raise IOError
        except (IOError, OSError) as e:
            try:
                if os.path.exists(temp_path):
                    os.unlink(temp_path)
            except Exception:
                pass
            raise UnableToWriteFile() from e
        try:
            os.rename(temp_path, Clsudo.filepath)
        except OSError as e:
            raise UnableToWriteFile() from e

    @staticmethod
    def _is_file_valid(filename):
        cmd = [
            '/usr/sbin/visudo',
            '-c',
            '-f', filename
        ]
        with subprocess.Popen(
            cmd,
            stdin=subprocess.DEVNULL,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
        ) as proc:
            proc.communicate()
            if proc.returncode != 0:
                return False
        return True