fix(auth): a narrowed credential can no longer mint an unrestricted one - #121
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A `write`-scoped API token on an administrator's account could reach `Admin` in two requests. Every link verified against the code: POST /api/v2/oauth/authorize took Access::Write, so a token issued ["write"] — deliberately without admin — passed. authorize_native_client requires no registered client: any non-empty client_id, a loopback redirect and an S256 challenge mint a code, and the authorization row records no scopes. POST /api/v2/oauth/token is unauthenticated by design. The session it returns is built with an empty scope list, and an empty list is unrestricted, so Access::Admin opened. The category error was treating "mutate user data" and "issue a reference to this account" as one authority. They are not: the second hands out a credential, and the credential handed out is broader than the one that asked. `Access::Unrestricted` names that. It is a restriction, not a role — only a credential carrying no scope list at all may mint one — so an ordinary account still pairs its own devices from its own session, which is what the flow is for. What it refuses is doing so on behalf of a credential that was deliberately narrowed. A read-only token could never start the chain, since the route already required a write, and the Subsonic facade is unaffected: it authenticates on `subsonic_credential`, not on `api_token`. The durable fix is to carry the scopes through the grant, so a session is never broader than what issued it. That needs a column on `oauth_authorization` and on `session`; this closes the path today without a migration, and both the enum and the RFC say so. Also corrected: the doc comment on `authenticated` claimed "being an administrator does not widen a token". That was the false half. The token widened itself, and the sentence now says which half held. The test builds the whole chain and asserts it stops at the first step, then asserts the refusal belongs to the narrowing and not to the account: the same account's session still grants, and the same token still writes what it was given. It fails if the route is put back to Access::Write. Signed-off-by: InstaZDLL <github.105mh@8shield.net>
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Included review availability: 0 reviews are currently available. Your included PR review attempts over the past 7 days set your current allowance at 2 reviews per hour. 📝 WalkthroughWalkthroughLe niveau ChangesRestriction des privilèges OAuth
Estimated code review effort: 2 (Simple) | ~10 minutes Merge Risk: ⚪ Minimal · up to The change prevents narrowed credentials from minting unrestricted sessions while preserving ordinary account authorization and write behavior. No actionable merge-blocking risk remains beyond normal checks and review. Possibly related PRs
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In `@tests/v2_foundations.rs`:
- Around line 7987-8004: Update the write-scope test around the writes request
to create an accessible resource in the temporary database, then assert the
expected successful response status instead of merely asserting it is not
forbidden. Verify the persisted rating afterward, using the existing test
helpers and resource identifiers.
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docs/api-v2-guide.mddocs/rfcs/RFC-002-waveflow-server-v2.mdsrc/http.rstests/v2_foundations.rs
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The escalation test asserted the scoped token was `!= FORBIDDEN` on a rating against a fabricated UUID. That distinguished the scope gate — a `catalog:read` token answers 403 there — but it proved nothing beyond it: the request 404'd, and the assertion would have held just as well if the handler had become a no-op. The fixture now indexes one track, so the second half of the claim is a write: `204`, and the rating is read back from the catalogue afterwards. Both directions are checked, by breaking each in turn. Putting the authorization route back to `Access::Write` fails it at the escalation (`left: 200, right: 403`). Dropping `write` from what `Access::Write` accepts fails it at the write (`left: 403, right: 204`). One test, two opposite regressions, which is what the assertion is for: the refusal belongs to the narrowing, not to the account. Signed-off-by: InstaZDLL <github.105mh@8shield.net>
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Closes the privilege escalation the fourth-pass audit found. Every link was verified against
46fef28before anything was changed; the chain is real.The chain
A
write-scoped API token on an administrator's account reachedAdminin two requests.oauth_authorizetookAccess::Write(src/http.rs:1112)["write"], deliberately withoutadmin, passedauthorize_native_client(src/services.rs)client_id, a loopback redirect and an S256 challenge mint a code, and the authorization row records no scopesPOST /api/v2/oauth/token(src/lib.rs:269)issue_new_session(src/authentication.rs:288)scopes: Vec::new()Access::granted_byAccess::AdminopenedWhat limited it: a read-only token could never start the chain, because the route already required a write. The Subsonic façade is unaffected — it authenticates on
subsonic_credential, not onapi_token.The category error
The scope model treated mutating user data and issuing a reference to this account as one authority. They are not. The second hands out a credential, and the credential handed out is broader than the one that asked for it.
Access::Unrestrictednames that: only a credential carrying no scope list at all may mint one.It is a restriction, not a role. An ordinary account still pairs its own devices from its own session, which is what the authorization code flow is for. What it refuses is doing so on behalf of a credential that was deliberately narrowed.
Of the three options the audit offered, this is the second. The first — carrying the scopes through the grant, so a session is never broader than what issued it — is the durable fix and remains right; it needs a column on
oauth_authorizationand one onsession. Both the enum's doc comment and RFC-002 record it as the intended end state. The third, classifying the routeAdmin, is wrong in spirit: pairing a device is not an administrative act.A claim of mine that was false
The doc comment on
authenticatedread "being an administrator does not widen a token, and a token cannot promote an ordinary account." The second half held. The first did not — the token widened itself. The sentence now says which half is true and points at the level that closes the other.Test
The test builds the whole chain — mints a
["write"]token, then presents it to the authorization endpoint — and asserts it stops at the first step with403.It then asserts the refusal belongs to the narrowing and not to the account: the same account's session still grants a code, and the same token still performs an ordinary write. Both halves matter; a refusal that also broke the session would be a different bug.
It fails if the route is put back to
Access::Write— verified by doing exactly that (left: 200, right: 403).cargo fmt --check,cargo clippy --all-targets --all-features -- -D warnings, 34/34 integration tests. Encoding checked across all three double-encoding signatures.Still the first risk, and it is not this
docs/subsonic-compatibility.mdrecords six batches of wire changes since the last real client validation (Symfonium 2026-08-09, DSub and Juliet 2026-08-15): HTTP 200 throughout, the presence rule, ten new fields,albumArtists[], albumartists[]/genres[],getAlbumordering, playlist ownership, genre unification.Each is justified and covered by internal tests. None has been put in front of a real client. That remains the first risk of the project — ahead of this escalation, which at least required holding a token in the first place. Nothing should be tagged before those five rows are re-run and re-dated.
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Nouvelles fonctionnalités
Correctifs