KEY-WP-0019-T05 rested on "existing tests pass unchanged", which shows the move
onto internal/jose preserved behaviour but not that the behaviour is checked.
Disabling the RSA comparison in jose.Verify fails both callers' suites, so the
shared verifier is load-bearing on each path.
Correct the comment on the caller-side cases added with the move. It claimed the
existing tamper case fails on the signature segment's shape before any key is
used; it does not — appending eight characters leaves a decodable segment, so
that case does reach and does check the signature. The two new cases are still
worth their place for what a byte-level tamper cannot reach: a structurally valid
token signed by an unpublished key under a published kid tests that key selection
is bound to the key set, and an undersized modulus in the published set tests
that ParseJWKS strictness denies rather than falling through to the claims.
Record both in the workplan and in G01's status.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Completes KEY-WP-0019. Client.Verify now delegates JWK-set parsing and RS256
signature checking to internal/jose, so the caller path and upstream provider
verification share one implementation rather than two copies that drift. Its
claim policy stays put: audience and nonce bindings belong to the caller.
The existing authclient tests pass unchanged, which is the evidence the
migration preserved behaviour. One deliberate strictness increase: a key set
containing any malformed RSA signing key is refused outright rather than used
alongside a good key. KeyCape's /jwks publishes a single key, so no current
deployment is affected.
Adds direct tests for internal/jose. It is now the single verifier behind both
paths, and testing it only through its callers would leave duplicate key ids,
crit headers, even exponents and undersized moduli covered by accident.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Closes the remaining half of gap G01. The adapter decoded upstream ID-token
claims without verifying anything, justified in a comment by a server-to-server
TLS boundary that nothing enforced.
Operator decision: verify the token rather than police the transport. The hop is
to be HTTPS as defence in depth, but KeyCape does not monitor, check or gate on
that -- a transport check helps only when it is configured correctly, which is
the assumption it was meant to remove. Verification holds regardless of how the
token arrived, so no HTTPS validation or opt-in flag is added.
HandleCallback now verifies the RS256 signature against Authelia's published
keys, the issuer Authelia advertises, KeyCape's own client ID in the audience,
and a sane validity window, before any claim is trusted. It fails closed: an
unreachable or unparseable key set denies the login. The advertised jwks_uri
path is rebased onto the server-side token base URL so split-horizon deployments
resolve, with config overrides where that inference is wrong, and an unknown key
id triggers one refresh so provider rotation needs no restart.
The reusable half lives in internal/jose rather than being copied from
authclient's verifier, since duplicated verification is how two copies drift and
one misses a fix. Migrating authclient onto it is tracked as KEY-WP-0019-T05,
kept separate so it does not destabilise a tested path in this change.
Thirteen rejection cases plus algorithm and rotation coverage; with the
unverified parse restored all fifteen fail, so they test the fix rather than
merely passing.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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