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Direktori : /opt/imunify360/venv/lib64/python3.11/site-packages/restore_infected/ |
Current File : //opt/imunify360/venv/lib64/python3.11/site-packages/restore_infected/safe_fileops.py |
""" Mostly copy-pasting from `safe_fileops.py` of the Imunify360 project """ import os import shutil import stat from concurrent.futures import ProcessPoolExecutor from contextlib import ExitStack, contextmanager, suppress from functools import lru_cache, partial from pathlib import Path from typing import Optional, Union import distro R_FLAGS = os.O_RDONLY W_FLAGS = os.O_TRUNC | os.O_CREAT | os.O_WRONLY def drop(uid, gid, fun, *args): if os.getuid() == 0: os.setgroups([]) os.setgid(gid) os.setuid(uid) return fun(*args) @contextmanager def open_fd(path, flags, dir_fd=None): """ Context manager which wraps os.open and close file descriptor at the end """ fd = os.open(path, flags, dir_fd=dir_fd) try: yield fd finally: with suppress(OSError): # fd is already closed os.close(fd) @contextmanager def open_dir_fd(name: str): """ Context manager to get a directory file descriptor It also checks if a directory doesn't contain a symlink in the path :param name: full directory name """ with open_fd(name, os.O_DIRECTORY) as dir_fd: real = os.readlink("/proc/self/fd/{}".format(dir_fd)) if name != real: raise PermissionError("Operations on symlinks are prohibited") yield dir_fd def open_fobj(f: Union[str, int], mode, flags=0, dir_fd: Optional[int] = None): """ Context manager to open file object from file name or from file descriptor File object extended with 'st' attribute that contains os.stat_result of the opened file :param f: file name or file descriptor to open :param mode: mode for built-in open :param flags: flags for os.open, ignored if 'f' is a file descriptor :param dir_fd: directory descriptor, ignored if 'f' is a file descriptor """ if isinstance(f, str): f = os.open(f, flags=flags, dir_fd=dir_fd) return open(f, mode=mode) def make_readable(name: str, dir_fd: int): # make a file readable by its owner st = os.stat(name, dir_fd=dir_fd) os.chmod(name, mode=st.st_mode | stat.S_IRUSR, dir_fd=dir_fd) return st @contextmanager def safe_tuple(name: str, dir_fd: int, flags: int, is_safe: bool): """ If is_safe flag is True, open file descriptor using name and dir_fd If is_safe is False, return name and dir_fd as is """ if is_safe: with open_fd(name, dir_fd=dir_fd, flags=flags) as fd: yield fd, None else: yield name, dir_fd def _move( src_fd: int, src_mode: int, dst_f: Union[int, str], dst_dir_fd: Optional[int], _race_dst, ): with open_fobj(src_fd, "rb") as src_fo, open_fobj( dst_f, "wb", W_FLAGS, dst_dir_fd ) as dst_fo: if _race_dst: _race_dst() shutil.copyfileobj(src_fo, dst_fo) if isinstance(dst_f, str): # safe_dst == False os.chmod(dst_fo.fileno(), mode=src_mode) @lru_cache(1) def _crontab_path() -> Path: if "debian" in distro.like().split(): return Path("/var/spool/cron/crontabs") return Path("/var/spool/cron") def is_crontab(path: str) -> bool: return Path(path).parent == _crontab_path() def safe_move(src: str, dst: str, *, _race_src=None, _race_dst=None): src_dir, src_name = os.path.split(src) dst_dir, dst_name = os.path.split(dst) with ExitStack() as stack: src_dir_fd = stack.enter_context(open_dir_fd(src_dir)) src_st = make_readable(src_name, src_dir_fd) src_fd = stack.enter_context(open_fd(src_name, R_FLAGS, src_dir_fd)) dst_dir_fd = stack.enter_context(open_dir_fd(dst_dir)) safe_dst = is_crontab(dst) if safe_dst and os.stat(dst_dir_fd).st_mode & stat.S_ISVTX: # If the parent directory has the sticky bit set, # we can't overwrite an existing file, so delete it first with suppress(FileNotFoundError): os.unlink(dst_name, dir_fd=dst_dir_fd) dst_f, dst_dir_fd = stack.enter_context( safe_tuple(dst_name, dst_dir_fd, W_FLAGS, safe_dst) ) fn = partial( drop, src_st.st_uid, src_st.st_gid, _move, src_fd, src_st.st_mode, dst_f, dst_dir_fd, _race_dst, ) with ProcessPoolExecutor(max_workers=1) as executor: future = executor.submit(fn) future.result() if _race_src: _race_src() os.unlink(src_name, dir_fd=src_dir_fd) if safe_dst: os.chown(dst_f, src_st.st_uid, src_st.st_gid, dir_fd=dst_dir_fd) os.chmod(dst_f, src_st.st_mode, dir_fd=dst_dir_fd)