fix: let named CORS origins send credentials (closes #155)

A bookmarklet could never reach an instance behind reverse-proxy auth.
on_prepare echoed Access-Control-Allow-Origin but never sent
Access-Control-Allow-Credentials, and hardcoded Allow-Headers to
Content-Type, so both approaches the reporter suggested in 2022 still
failed in a browser today: credentials:'include' was rejected for the
missing Allow-Credentials, and an explicit Authorization header was
rejected as not allowed by the preflight.

Naming an origin in CORS_ALLOWED_ORIGINS is a deliberate trust grant, so
a named origin may now send credentials and an Authorization header. The
'*' wildcard is not such a grant: it matches origins the operator never
enumerated, and since credentials require echoing the origin back rather
than sending '*', pairing the two would let any site the user visits
drive their instance with their own session. The wildcard therefore
keeps byte-for-byte the uncredentialed behaviour it has always had, and
a '*' anywhere in the list disables credentials for every origin in it,
with a startup warning so that combination is not silently confusing.

This matches the boundary socket.io already enforces: engineio defaults
cors_credentials to True, and its wildcard test is against the string
'*' while we pass a list, so it too grants credentials only to
explicitly listed origins.

Also sets Vary: Origin, appending rather than clobbering, so a shared
cache cannot hand one origin's Allow-Origin to another.

Verified in a real browser across the matrix: with the caller's origin
named, plain/credentialed/Authorization requests all succeed; under '*'
the credentialed and Authorization requests stay blocked; from an
unlisted origin everything stays blocked.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
Alex Shnitman
2026-08-20 09:39:26 +02:00
parent 86954784fd
commit c393e0195b
3 changed files with 173 additions and 5 deletions
+2 -2
View File
@@ -98,7 +98,7 @@ Enabling `writeinfojson` or `writethumbnail` in `YTDL_OPTIONS` also writes a fee
* __HTTPS__: Use `https` instead of `http` (__CERTFILE__ and __KEYFILE__ required). Defaults to `false`.
* __CERTFILE__: HTTPS certificate file path.
* __KEYFILE__: HTTPS key file path.
* __CORS_ALLOWED_ORIGINS__: Comma-separated list of origins permitted to make cross-origin requests to the MeTube API; `*` allows all. When unset or empty, all cross-origin requests are denied. Required for browser extensions and bookmarklets — see [Sending links to MeTube](#-sending-links-to-metube).
* __CORS_ALLOWED_ORIGINS__: Comma-separated list of origins permitted to make cross-origin requests to the MeTube API; `*` allows all. When unset or empty, all cross-origin requests are denied. Required for browser extensions and bookmarklets — see [Sending links to MeTube](#-sending-links-to-metube). Naming origins explicitly also lets them send credentials (a login cookie, or the `Authorization` header a reverse proxy checks), which `*` deliberately does not: it would let any site you visit drive your instance with your own session.
* __ROBOTS_TXT__: A path to a `robots.txt` file mounted in the container.
## 🎛️ Configuring yt-dlp options
@@ -243,7 +243,7 @@ __Browser extensions__ allow right-clicking videos and sending them directly to
* __Chrome:__ contributed by [Rpsl](https://github.com/rpsl) — install from the [Chrome Webstore](https://chrome.google.com/webstore/detail/metube-downloader/fbmkmdnlhacefjljljlbhkodfmfkijdh) or [from sources](https://github.com/Rpsl/metube-browser-extension).
* __Firefox:__ contributed by [nanocortex](https://github.com/nanocortex) — install from [Firefox Addons](https://addons.mozilla.org/en-US/firefox/addon/metube-downloader) or get sources [here](https://github.com/nanocortex/metube-firefox-addon).
__Bookmarklets__ send the currently open page to MeTube with one click. Add the origins of the sites where you use them to `CORS_ALLOWED_ORIGINS`, e.g. `https://www.youtube.com,https://www.vimeo.com`. The code (Chrome and Firefox variants, contributed by [kushfest](https://github.com/kushfest) and [shoonya75](https://github.com/shoonya75)) is in the [Bookmarklets wiki page](https://github.com/alexta69/metube/wiki/Bookmarklets).
__Bookmarklets__ send the currently open page to MeTube with one click. Add the origins of the sites where you use them to `CORS_ALLOWED_ORIGINS`, e.g. `https://www.youtube.com,https://www.vimeo.com`. If your instance sits behind authentication, list the origins individually rather than using `*` — only named origins are allowed to send credentials. The code (Chrome and Firefox variants, contributed by [kushfest](https://github.com/kushfest) and [shoonya75](https://github.com/shoonya75)) is in the [Bookmarklets wiki page](https://github.com/alexta69/metube/wiki/Bookmarklets).
__iOS Shortcut:__ [rithask](https://github.com/rithask) created an [iOS shortcut](https://www.icloud.com/shortcuts/66627a9f334c467baabdb2769763a1a6) for sending URLs to MeTube from Safari's share menu; it prompts for your instance address on first use.