peter
733b41fd86
- C-3.7: fold a per-link password_version into the signed watch grant (migration
0059 adds the column) and bump it on every password change, so rotating a share
link's password invalidates outstanding grants at once instead of letting them
live out the 6h TTL. make_grant/check_grant take the version; update_link bumps.
- C-3.8: the share recipient picker and share-by-email now reuse the messageable
filter (not-demo AND active AND not-suspended) instead of only excluding demo,
so suspended/deactivated addresses aren't leaked or reachable as targets.
- C-3.9: GET /keys/{user_id} adopts get_thread's MB2 guard — a non-messageable
target with no shared history returns the same "User not found" as a missing id,
so it can't be probed to enumerate users or fetch suspended users' keys.
- C-3.12: _register_account catches IntegrityError on the insert (the select-then-
insert TOCTOU) and treats it as the already-registered no-op.
- C-3.13: trigger_job claims the running flag atomically under _activity_lock
(compare-and-set) instead of a bare check, closing the double-start window.
- Move _messageable/is_messageable_user into a shared app/userscope.py so downloads
doesn't import the messages route module.
96 lines
3.9 KiB
Python
96 lines
3.9 KiB
Python
"""Public "share by link" helpers for the download center.
|
|
|
|
A DownloadLink is a capability URL: the unguessable `token` grants anyone read access to one
|
|
download's file on the login-free `/watch/{token}` page. Password-protected links additionally
|
|
require a short-lived signed **grant** on the file request — because a `<video src>` can't send a
|
|
header, the password is exchanged once at `/unlock` for an HMAC grant appended to the file URL,
|
|
so the raw password never rides in the media URL (or server logs).
|
|
"""
|
|
import hashlib
|
|
import hmac
|
|
import secrets
|
|
from datetime import datetime, timezone
|
|
|
|
from app.config import settings
|
|
from app.models import DownloadLink
|
|
|
|
_GRANT_TTL = 6 * 3600 # a watch session's grant is good for 6h, then the viewer re-unlocks
|
|
|
|
|
|
def new_token() -> str:
|
|
return secrets.token_urlsafe(24) # ~32 chars, 192 bits
|
|
|
|
|
|
def is_expired(link: DownloadLink) -> bool:
|
|
return link.expires_at is not None and link.expires_at <= datetime.now(timezone.utc)
|
|
|
|
|
|
# --- signed grants (password-protected file access) ----------------------------------------
|
|
|
|
def _sign(msg: str) -> str:
|
|
return hmac.new(
|
|
settings.secret_key.encode(), msg.encode(), hashlib.sha256
|
|
).hexdigest()[:32]
|
|
|
|
|
|
def make_grant(token: str, password_version: int, now: float | None = None) -> str:
|
|
"""A short-lived HMAC grant proving the viewer unlocked `token`. Format: `<exp>.<sig>`. The
|
|
link's current `password_version` is folded into the signature, so rotating the password (which
|
|
bumps the version) invalidates every grant minted under the old password at once."""
|
|
exp = int((now if now is not None else datetime.now(timezone.utc).timestamp())) + _GRANT_TTL
|
|
return f"{exp}.{_sign(f'{token}.{exp}.{password_version}')}"
|
|
|
|
|
|
def check_grant(token: str, grant: str | None, password_version: int) -> bool:
|
|
"""Verify a grant against the link's CURRENT `password_version`; a version bump (password
|
|
rotation) fails the signature check even before the grant's TTL expires."""
|
|
if not grant or "." not in grant:
|
|
return False
|
|
exp_s, sig = grant.split(".", 1)
|
|
try:
|
|
exp = int(exp_s)
|
|
except ValueError:
|
|
return False
|
|
if exp < datetime.now(timezone.utc).timestamp():
|
|
return False
|
|
return hmac.compare_digest(sig, _sign(f"{token}.{exp}.{password_version}"))
|
|
|
|
|
|
# --- serialization -------------------------------------------------------------------------
|
|
|
|
def owner_view(link: DownloadLink, base_url: str = "") -> dict:
|
|
"""What the file owner sees when managing their links."""
|
|
return {
|
|
"id": link.id,
|
|
"token": link.token,
|
|
"url": f"{base_url}/watch/{link.token}",
|
|
"allow_download": link.allow_download,
|
|
"has_password": link.password_hash is not None,
|
|
"expires_at": link.expires_at.isoformat() if link.expires_at else None,
|
|
"view_count": link.view_count,
|
|
"created_at": link.created_at.isoformat() if link.created_at else None,
|
|
}
|
|
|
|
|
|
def public_meta(link: DownloadLink, job, asset, file_url: str, poster_url: str | None = None) -> dict:
|
|
"""Metadata for the public watch page (only ever returned once access is authorized).
|
|
|
|
Resolves the owner's per-download display overrides (custom title/channel) over the asset's
|
|
auto-extracted values, and surfaces the source + any extra reference links as clickable URLs."""
|
|
from app.downloads import service
|
|
|
|
source_url = service.reference_url(job, asset)
|
|
return {
|
|
"title": (job and job.display_name) or asset.title,
|
|
"uploader": (job and job.display_uploader) or asset.uploader,
|
|
"uploader_url": (job and job.display_uploader_url) or asset.uploader_url,
|
|
"source_url": source_url,
|
|
"extra_links": (job and job.extra_links) or [],
|
|
"duration_s": asset.duration_s,
|
|
"width": asset.width,
|
|
"height": asset.height,
|
|
"allow_download": link.allow_download,
|
|
"file_url": file_url,
|
|
"poster_url": poster_url,
|
|
}
|