anti
4b15b7eb35
'sudo decnet deploy' needs root for MACVLAN, but the log files it creates (decnet.log and decnet.system.log) end up owned by root. A subsequent non-root 'decnet api' then crashes on PermissionError appending to them. New decnet.privdrop helper reads SUDO_UID/SUDO_GID and chowns files/dirs back to the invoking user. Best-effort: no-op when not root, not under sudo, path missing, or chown fails. Applied at both log-file creation sites (config.py system log, logging/file_handler.py syslog file).
68 lines
2.0 KiB
Python
68 lines
2.0 KiB
Python
"""
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Helpers for dropping root ownership on files created during privileged
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operations (e.g. `sudo decnet deploy` needs root for MACVLAN, but its log
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files should be owned by the invoking user so a subsequent non-root
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`decnet api` can append to them).
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When sudo invokes a process, it sets SUDO_UID / SUDO_GID in the
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environment to the original user's IDs. We use those to chown files
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back after creation.
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"""
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from __future__ import annotations
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import os
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from pathlib import Path
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from typing import Optional
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def _sudo_ids() -> Optional[tuple[int, int]]:
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"""Return (uid, gid) of the sudo-invoking user, or None when the
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process was not launched via sudo / the env vars are missing."""
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raw_uid = os.environ.get("SUDO_UID")
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raw_gid = os.environ.get("SUDO_GID")
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if not raw_uid or not raw_gid:
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return None
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try:
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return int(raw_uid), int(raw_gid)
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except ValueError:
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return None
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def chown_to_invoking_user(path: str | os.PathLike[str]) -> None:
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"""Best-effort chown of *path* to the sudo-invoking user.
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No-op when:
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* not running as root (nothing to drop),
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* not launched via sudo (no SUDO_UID/SUDO_GID),
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* the path does not exist,
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* chown fails (logged-only — never raises).
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"""
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if os.geteuid() != 0:
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return
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ids = _sudo_ids()
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if ids is None:
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return
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uid, gid = ids
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p = Path(path)
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if not p.exists():
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return
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try:
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os.chown(p, uid, gid)
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except OSError:
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# Best-effort; a failed chown is not fatal to logging.
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pass
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def chown_tree_to_invoking_user(root: str | os.PathLike[str]) -> None:
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"""Apply :func:`chown_to_invoking_user` to *root* and every file/dir
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beneath it. Used for parent directories that we just created with
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``mkdir(parents=True)`` as root."""
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if os.geteuid() != 0 or _sudo_ids() is None:
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return
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root_path = Path(root)
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if not root_path.exists():
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return
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chown_to_invoking_user(root_path)
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for entry in root_path.rglob("*"):
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chown_to_invoking_user(entry)
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