from __future__ import annotations import shlex import time from dataclasses import dataclass from pathlib import Path from typing import Optional, List from . import disk from .general import SysCommand, generate_password, SysCommandWorker from .output import info, debug from .exceptions import SysCallError, DiskError from .storage import storage @dataclass class Luks2: luks_dev_path: Path mapper_name: Optional[str] = None password: Optional[str] = None key_file: Optional[Path] = None auto_unmount: bool = False # will be set internally after unlocking the device _mapper_dev: Optional[Path] = None @property def mapper_dev(self) -> Optional[Path]: if self.mapper_name: return Path(f'/dev/mapper/{self.mapper_name}') return None def __post_init__(self): if self.luks_dev_path is None: raise ValueError('Partition must have a path set') def __enter__(self): self.unlock(self.key_file) def __exit__(self, *args: str, **kwargs: str): if self.auto_unmount: self.lock() def _default_key_file(self) -> Path: return Path(f'/tmp/{self.luks_dev_path.name}.disk_pw') def _password_bytes(self) -> bytes: if not self.password: raise ValueError('Password for luks2 device was not specified') if isinstance(self.password, bytes): return self.password else: return bytes(self.password, 'UTF-8') def encrypt( self, key_size: int = 512, hash_type: str = 'sha512', iter_time: int = 10000, key_file: Optional[Path] = None ) -> Path: info(f'Luks2 encrypting: {self.luks_dev_path}') byte_password = self._password_bytes() if not key_file: if self.key_file: key_file = self.key_file else: key_file = self._default_key_file() with open(key_file, 'wb') as fh: fh.write(byte_password) cryptsetup_args = shlex.join([ '/usr/bin/cryptsetup', '--batch-mode', '--verbose', '--type', 'luks2', '--pbkdf', 'argon2id', '--hash', hash_type, '--key-size', str(key_size), '--iter-time', str(iter_time), '--key-file', str(key_file), '--use-urandom', 'luksFormat', str(self.luks_dev_path), ]) # Retry formatting the volume because archinstall can some times be too quick # which generates a "Device /dev/sdX does not exist or access denied." between # setting up partitions and us trying to encrypt it. for retry_attempt in range(storage['DISK_RETRY_ATTEMPTS'] + 1): try: SysCommand(cryptsetup_args) break except SysCallError as err: time.sleep(storage['DISK_TIMEOUTS']) if retry_attempt != storage['DISK_RETRY_ATTEMPTS']: continue if err.exit_code == 1: info(f'luks2 partition currently in use: {self.luks_dev_path}') info('Attempting to unmount, crypt-close and trying encryption again') self.lock() # Then try again to set up the crypt-device SysCommand(cryptsetup_args) else: raise DiskError(f'Could not encrypt volume "{self.luks_dev_path}": {err}') return key_file def _get_luks_uuid(self) -> str: command = f'/usr/bin/cryptsetup luksUUID {self.luks_dev_path}' try: return SysCommand(command).decode() except SysCallError as err: info(f'Unable to get UUID for Luks device: {self.luks_dev_path}') raise err def is_unlocked(self) -> bool: return self.mapper_name is not None and Path(f'/dev/mapper/{self.mapper_name}').exists() def unlock(self, key_file: Optional[Path] = None): """ Unlocks the luks device, an optional key file location for unlocking can be specified, otherwise a default location for the key file will be used. :param key_file: An alternative key file :type key_file: Path """ debug(f'Unlocking luks2 device: {self.luks_dev_path}') if not self.mapper_name: raise ValueError('mapper name missing') byte_password = self._password_bytes() if not key_file: if self.key_file: key_file = self.key_file else: key_file = self._default_key_file() with open(key_file, 'wb') as fh: fh.write(byte_password) wait_timer = time.time() while Path(self.luks_dev_path).exists() is False and time.time() - wait_timer < 10: time.sleep(0.025) SysCommand(f'/usr/bin/cryptsetup open {self.luks_dev_path} {self.mapper_name} --key-file {key_file} --type luks2') if not self.mapper_dev or not self.mapper_dev.is_symlink(): raise DiskError(f'Failed to open luks2 device: {self.luks_dev_path}') def lock(self): disk.device_handler.umount(self.luks_dev_path) # Get crypt-information about the device by doing a reverse lookup starting with the partition path # For instance: /dev/sda lsblk_info = disk.get_lsblk_info(self.luks_dev_path) # For each child (sub-partition/sub-device) for child in lsblk_info.children: # Unmount the child location for mountpoint in child.mountpoints: debug(f'Unmounting {mountpoint}') disk.device_handler.umount(mountpoint, recursive=True) # And close it if possible. debug(f"Closing crypt device {child.name}") SysCommand(f"cryptsetup close {child.name}") self._mapper_dev = None def create_keyfile(self, target_path: Path, override: bool = False): """ Routine to create keyfiles, so it can be moved elsewhere """ if self.mapper_name is None: raise ValueError('Mapper name must be provided') # Once we store the key as ../xyzloop.key systemd-cryptsetup can # automatically load this key if we name the device to "xyzloop" kf_path = Path(f'/etc/cryptsetup-keys.d/{self.mapper_name}.key') key_file = target_path / kf_path.relative_to(kf_path.root) crypttab_path = target_path / 'etc/crypttab' if key_file.exists(): if not override: info(f'Key file {key_file} already exists, keeping existing') return else: info(f'Key file {key_file} already exists, overriding') key_file.parent.mkdir(parents=True, exist_ok=True) with open(key_file, "w") as keyfile: keyfile.write(generate_password(length=512)) key_file.chmod(0o400) self._add_key(key_file) self._crypttab(crypttab_path, kf_path, options=["luks", "key-slot=1"]) def _add_key(self, key_file: Path): info(f'Adding additional key-file {key_file}') command = f'/usr/bin/cryptsetup -q -v luksAddKey {self.luks_dev_path} {key_file}' worker = SysCommandWorker(command, environment_vars={'LC_ALL': 'C'}) pw_injected = False while worker.is_alive(): if b'Enter any existing passphrase' in worker and pw_injected is False: worker.write(self._password_bytes()) pw_injected = True if worker.exit_code != 0: raise DiskError(f'Could not add encryption key {key_file} to {self.luks_dev_path}: {worker.decode()}') def _crypttab( self, crypttab_path: Path, key_file: Path, options: List[str] ) -> None: info(f'Adding crypttab entry for key {key_file}') with open(crypttab_path, 'a') as crypttab: opt = ','.join(options) uuid = self._get_luks_uuid() row = f"{self.mapper_name} UUID={uuid} {key_file} {opt}\n" crypttab.write(row)