anti
9fc489258b
A stolen JWT used to survive a password reset for its full 24h. Now every session-invalidating change moves the user's tokens_valid_from cutoff to 'now', so all of that user's prior tokens 401 on next use: - self change-password, admin reset-password, role change all bump the cutoff (delete needs no bump: the row is gone, so the user lookup 401s). - Cutoff is compared against the token's iat floored to whole seconds, so a re-login in the same second as the change isn't caught by its own revocation (the cost is a <=1s grey zone on same-second-old tokens). - Per-user: changing one user never revokes another.
319 lines
12 KiB
Python
319 lines
12 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-or-later
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import asyncio
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import time
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from datetime import datetime, timezone
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from typing import Any, Optional
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import jwt
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from fastapi import HTTPException, status, Request
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from fastapi.security import OAuth2PasswordBearer
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from decnet.web.auth import ALGORITHM, SECRET_KEY
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from decnet.web.db.repository import BaseRepository
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from decnet.web.db.factory import get_repository
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# Shared repository singleton
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_repo: Optional[BaseRepository] = None
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def get_repo() -> BaseRepository:
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"""FastAPI dependency to inject the configured repository."""
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global _repo
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if _repo is None:
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_repo = get_repository()
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return _repo
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repo = get_repo()
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oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/v1/auth/login")
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# Per-request user lookup was the hidden tax behind every authed endpoint —
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# SELECT users WHERE uuid=? ran once per call, serializing through aiosqlite.
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# 10s TTL is well below JWT expiry and we invalidate on all user writes.
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_USER_TTL = 10.0
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_user_cache: dict[str, tuple[Optional[dict[str, Any]], float]] = {}
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_user_cache_lock: Optional[asyncio.Lock] = None
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# Username cache for the login hot path. Short TTL — the bcrypt verify
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# still runs against the cached hash, so security is unchanged. The
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# staleness window is: if a password is changed, the old password is
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# usable for up to _USERNAME_TTL seconds until the cache expires (or
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# invalidate_user_cache fires). We invalidate on every user write.
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# Missing lookups are NOT cached to avoid locking out a just-created user.
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_USERNAME_TTL = 5.0
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_username_cache: dict[str, tuple[dict[str, Any], float]] = {}
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_username_cache_lock: Optional[asyncio.Lock] = None
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# Denylist membership cache for revoked jti lookups. Same 10s envelope as the
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# user cache: a token revoked elsewhere stops working within _REVOKED_TTL. In
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# this process we drop the stale entry on revoke (see invalidate_token_cache),
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# so logout is immediate locally; the TTL only bounds cross-worker staleness.
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_REVOKED_TTL = 10.0
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_revoked_cache: dict[str, tuple[bool, float]] = {}
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_revoked_cache_lock: Optional[asyncio.Lock] = None
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def _reset_user_cache() -> None:
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global _user_cache, _user_cache_lock, _username_cache, _username_cache_lock
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global _revoked_cache, _revoked_cache_lock
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_user_cache = {}
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_user_cache_lock = None
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_username_cache = {}
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_username_cache_lock = None
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_revoked_cache = {}
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_revoked_cache_lock = None
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def invalidate_user_cache(user_uuid: Optional[str] = None) -> None:
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"""Drop a single user (or all users) from the auth caches.
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Callers: password change, role change, user create/delete.
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The username cache is always cleared wholesale — we don't track
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uuid→username and user writes are rare, so the cost is trivial.
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"""
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if user_uuid is None:
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_user_cache.clear()
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else:
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_user_cache.pop(user_uuid, None)
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_username_cache.clear()
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def invalidate_token_cache(jti: Optional[str] = None) -> None:
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"""Drop a single jti (or the whole denylist cache) so the next request
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re-reads revocation state from the DB. Called right after ``revoke_token``
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so a logged-out token stops working immediately in this process."""
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if jti is None:
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_revoked_cache.clear()
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else:
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_revoked_cache.pop(jti, None)
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async def get_user_by_username_cached(username: str) -> Optional[dict[str, Any]]:
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"""Cached read of get_user_by_username for the login path.
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Positive hits are cached for _USERNAME_TTL seconds. Misses bypass
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the cache so a freshly-created user can log in immediately.
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"""
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global _username_cache_lock
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entry = _username_cache.get(username)
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now = time.monotonic()
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if entry is not None and now - entry[1] < _USERNAME_TTL:
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return entry[0]
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if _username_cache_lock is None:
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_username_cache_lock = asyncio.Lock()
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async with _username_cache_lock:
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entry = _username_cache.get(username)
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now = time.monotonic()
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if entry is not None and now - entry[1] < _USERNAME_TTL:
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return entry[0]
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user = await repo.get_user_by_username(username)
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if user is not None:
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_username_cache[username] = (user, time.monotonic())
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return user
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async def _get_user_cached(user_uuid: str) -> Optional[dict[str, Any]]:
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global _user_cache_lock
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entry = _user_cache.get(user_uuid)
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now = time.monotonic()
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if entry is not None and now - entry[1] < _USER_TTL:
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return entry[0]
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if _user_cache_lock is None:
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_user_cache_lock = asyncio.Lock()
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async with _user_cache_lock:
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entry = _user_cache.get(user_uuid)
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now = time.monotonic()
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if entry is not None and now - entry[1] < _USER_TTL:
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return entry[0]
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user = await repo.get_user_by_uuid(user_uuid)
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_user_cache[user_uuid] = (user, time.monotonic())
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return user
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async def _is_revoked_cached(jti: str) -> bool:
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global _revoked_cache_lock
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entry = _revoked_cache.get(jti)
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now = time.monotonic()
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if entry is not None and now - entry[1] < _REVOKED_TTL:
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return entry[0]
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if _revoked_cache_lock is None:
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_revoked_cache_lock = asyncio.Lock()
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async with _revoked_cache_lock:
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entry = _revoked_cache.get(jti)
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now = time.monotonic()
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if entry is not None and now - entry[1] < _REVOKED_TTL:
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return entry[0]
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revoked = await repo.is_token_revoked(jti)
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_revoked_cache[jti] = (revoked, time.monotonic())
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return revoked
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_CREDENTIALS_EXCEPTION = HTTPException(
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status_code=status.HTTP_401_UNAUTHORIZED,
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detail="Could not validate credentials",
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headers={"WWW-Authenticate": "Bearer"},
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)
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def _epoch(value: Any) -> float:
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"""Coerce a JWT ``iat`` (int seconds) or a stored datetime to UTC epoch
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seconds so the two can be compared regardless of source. Naive datetimes
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(SQLite round-trips lose tzinfo) are treated as the UTC we wrote."""
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if isinstance(value, (int, float)):
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return float(value)
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if isinstance(value, datetime):
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aware = value.replace(tzinfo=timezone.utc) if value.tzinfo is None else value
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return aware.timestamp()
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raise _CREDENTIALS_EXCEPTION
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def _decode_payload(token: str) -> dict[str, Any]:
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"""Decode + signature/expiry-verify a raw JWT, or raise 401."""
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try:
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payload: dict[str, Any] = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
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except jwt.PyJWTError:
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raise _CREDENTIALS_EXCEPTION
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if payload.get("uuid") is None:
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raise _CREDENTIALS_EXCEPTION
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return payload
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async def _resolve_token(token: str) -> tuple[str, dict[str, Any]]:
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"""Decode a token, load its user, and enforce revocation. Returns
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``(user_uuid, user_dict)`` or raises 401. Single chokepoint so every auth
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path (header, SSE query param, role gates) shares identical revocation
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semantics."""
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payload = _decode_payload(token)
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user_uuid: str = payload["uuid"]
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user = await _get_user_cached(user_uuid)
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if not user:
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# Unknown / deleted user — also covers the user-delete revocation case.
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raise _CREDENTIALS_EXCEPTION
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# 1. Legacy tokens minted before jti existed cannot be revoked — fail closed
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# so a deploy of this feature forces exactly one re-login.
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jti = payload.get("jti")
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if not jti:
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raise _CREDENTIALS_EXCEPTION
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# 2. Bulk cutoff: password/role change moves tokens_valid_from forward.
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# JWT iat is whole-seconds, so floor the cutoff to whole seconds too —
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# otherwise a re-login landing in the SAME second as the change gets an
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# iat that truncates below a sub-second cutoff and is wrongly rejected.
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# Cost: tokens issued earlier in that same second survive (≤1s), which is
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# negligible against a 24h lifetime.
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cutoff = user.get("tokens_valid_from")
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if cutoff is not None and _epoch(payload.get("iat", 0)) < int(_epoch(cutoff)):
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raise _CREDENTIALS_EXCEPTION
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# 3. Single-token denylist (logout).
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if await _is_revoked_cached(jti):
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raise _CREDENTIALS_EXCEPTION
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return user_uuid, user
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def _bearer_from_header(request: Request) -> Optional[str]:
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auth = request.headers.get("Authorization")
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if auth and auth.startswith("Bearer "):
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return auth.split(" ", 1)[1]
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return None
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async def _resolve_request(request: Request) -> tuple[str, dict[str, Any]]:
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"""Bearer-header variant of :func:`_resolve_token`."""
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token = _bearer_from_header(request)
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if not token:
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raise _CREDENTIALS_EXCEPTION
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return await _resolve_token(token)
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async def get_token_claims(request: Request) -> dict[str, Any]:
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"""Return the validated claims of the presented Bearer token (decode +
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signature + user-exists + revocation checks, but NOT must_change). Used by
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logout, which needs the token's own ``jti``/``exp`` to denylist *this*
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session — and must still reject an already-revoked token."""
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token = _bearer_from_header(request)
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if not token:
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raise _CREDENTIALS_EXCEPTION
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await _resolve_token(token) # enforce user-exists + revocation; raises 401
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return _decode_payload(token)
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async def get_stream_user(request: Request, token: Optional[str] = None) -> str:
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"""Auth dependency for SSE endpoints — accepts Bearer header OR ?token= query param.
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EventSource does not support custom headers, so the query-string fallback is intentional here only.
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"""
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resolved = _bearer_from_header(request) or token
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if not resolved:
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raise _CREDENTIALS_EXCEPTION
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# Decode-only: returns the uuid. Revocation/role enforcement happens in
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# require_stream_role (the sole production caller), which runs the full
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# _resolve_token path. Kept thin so its decode contract stays unit-testable.
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return _decode_payload(resolved)["uuid"]
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async def get_current_user(request: Request) -> str:
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"""Auth dependency — enforces must_change_password."""
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_user_uuid, _user = await _resolve_request(request)
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if _user.get("must_change_password"):
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raise HTTPException(
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status_code=status.HTTP_403_FORBIDDEN,
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detail="Password change required before accessing this resource",
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)
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return _user_uuid
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async def get_current_user_unchecked(request: Request) -> str:
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"""Auth dependency — skips must_change_password enforcement (but still
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enforces signature, user existence, and revocation).
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Use only for endpoints that must remain reachable with the flag set (e.g. change-password).
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"""
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_user_uuid, _user = await _resolve_request(request)
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return _user_uuid
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# ---------------------------------------------------------------------------
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# Role-based access control
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# ---------------------------------------------------------------------------
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def require_role(*allowed_roles: str):
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"""Factory that returns a FastAPI dependency enforcing role membership.
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Inlines JWT decode + user lookup + must_change_password + role check so the
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user is only loaded from the DB once per request (not once in
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``get_current_user`` and again here). Returns the full user dict so
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endpoints can inspect ``user["uuid"]``, ``user["role"]``, etc.
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"""
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async def _check(request: Request) -> dict:
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_user_uuid, user = await _resolve_request(request)
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if user.get("must_change_password"):
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raise HTTPException(
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status_code=status.HTTP_403_FORBIDDEN,
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detail="Password change required before accessing this resource",
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)
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if user["role"] not in allowed_roles:
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raise HTTPException(
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status_code=status.HTTP_403_FORBIDDEN,
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detail="Insufficient permissions",
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)
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return user
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return _check
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def require_stream_role(*allowed_roles: str):
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"""Like ``require_role`` but for SSE endpoints that accept a query-param token."""
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async def _check(request: Request, token: Optional[str] = None) -> dict:
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resolved = _bearer_from_header(request) or token
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if not resolved:
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raise _CREDENTIALS_EXCEPTION
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_user_uuid, user = await _resolve_token(resolved)
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if user["role"] not in allowed_roles:
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raise HTTPException(
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status_code=status.HTTP_403_FORBIDDEN,
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detail="Insufficient permissions",
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)
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return user
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return _check
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require_admin = require_role("admin")
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require_viewer = require_role("viewer", "admin")
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require_stream_viewer = require_stream_role("viewer", "admin")
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