Evan JarrettandClaude Opus 5 2719428071 appview: give each registry domain its own JWT service name ...

An AppView can front several registry domains that all reach the same
backend (seamark.dev serving buoy.cr, seamark.cr, and soon atcr.io).
Distribution's token access controller holds `service` as a single string
and uses it twice: as the value advertised in the WWW-Authenticate
challenge, and as the sole accepted JWT audience. So it announced one
domain's name on every domain, and honoured one domain's tokens
everywhere. A push to seamark.cr was challenged with service="buoy.cr".

Both uses sit inside Authorized, which already has the request, but the
value is fixed at construction and reachable through no hook — autoredirect
only templates the realm. So register an "atcr-token" controller that
builds one upstream controller per domain and dispatches on r.Host. Each
front door now advertises its own name and demands its own audience. All
signature, certificate and claim verification stays in upstream code; this
only routes.

The token handler stops discarding ?service= and stamps the audience with
the front door the client used, allowlist-checked against the configured
domains so the value stays server-determined despite arriving from the
client. It has to come from the query param because the realm lives on the
UI host, where r.Host names no registry domain.

This is token hygiene and spec conformance, not a privilege boundary: every
domain fronts the same backend, so a client can obtain a token for any of
them just by handshaking there. What it buys is a truthful challenge and
the decoupling needed to later split a domain onto its own AppView.

Also unify the domain list. DomainRoutingMiddleware keyed its map on the
raw config while matching a port-stripped host, so a domain configured with
a port could never match its own requests. It now shares the normalized
cfg.Auth.Services, so routing and authorization agree on one set of names.
cfg.Auth.ServiceName was an exact alias for Services[0] and is replaced by
PrimaryService(), which also removes an empty-slice index.

Rollout: the audience for seamark.cr and bouy.cr changes, so a token minted
just before the restart draws one 401 and Docker re-handshakes into a valid
one. buoy.cr is unchanged (it stays primary), and atcr.io keeps the service
name it already has today. The challenge and the accepted audience come
from the same delegate, so the retry converges by construction. Deploy as a
single flip, not a canary: an old instance ignores ?service= and would keep
minting the primary audience while a new one rejects it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

2026-08-02 20:40:55 -05:00

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testharness

appview: give each registry domain its own JWT service name

2026-08-02 20:40:55 -05:00