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| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Will Pfleger
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953a1798b2 |
feat(auth): add NIP-FI canonical assertion verifier and contracts (#6776)
The closed, provider-neutral contract layer at the root of the NIP-FI federated-identity dependency graph — Phase A, PR 1 of the plan. It has no dependencies on any other PR and defines no database schema, migration, runtime JWKS fetching, binding resolution, enrollment, or request/proof binding; those belong to later PRs. ## What this adds - **Multi-issuer assertion-policy config** (`IssuerRegistry`, `IssuerPolicy`) keyed by exact `iss`. Identity is issuer-qualified `(iss, sub)` throughout — equal `sub` under different `iss` are distinct identities. The subject coordinate is fixed to the JWT `sub` claim (`SUBJECT_CLAIM`), never configurable, so no deployment can seal a mutable attribute like `email` as identity. Issuer URL and audience remain deployment configuration. - **The two deterministic semantic contract identities** — `AssertionPolicyId = H(canonical assertion-policy contract)` and `TransportContractId = H(canonical transport contract)` — derived by length-prefixed, domain-separated SHA-256 so a semantic change moves exactly its owning ID while benign JWKS rotation never changes policy lineage. Set-valued policy inputs (audiences, algorithms, subject-class values, scope capture) are canonicalized before derivation, so the ID is invariant under permutation and duplication. Config fields that a freshness class never reads are rejected at construction (an `offline-jwt` policy cannot carry `maximum_status_age`), so the canonical encoding stays total over valid configs and semantically identical policies always derive one ID. - **The single canonical verifier** (`FederatedAssertionVerifier`, `FI-INV-16`) producing the origin-sealed, provider-neutral `VerifiedAssertion` normalized result. Its constructor is crate-private, so unverified claims cannot be promoted into authority. The issuer→JWKS authority is entirely crate-owned: `AssertionKeySet` has no public constructor and `IssuerKeySource` is sealed, so no downstream crate can relabel one issuer's keys as another's. The authenticated key set is bounded (`MAX_JWKS_KEYS`) and the bound is folded into `AssertionPolicyId`, so an unbounded attacker-controlled `kid` scan cannot be driven; every snapshot requires a finite positive hard deadline. - **Sealed revalidation dependencies** — `RevalidationDependencies` carries the key-snapshot hard deadline and a `ConfidentialAssertion` handle to the exact compact JWS (no `Debug`/`Display`/`serde` leak, sole read path `compact_jws()`), so a changed snapshot can revalidate the same evidence: a retained key revalidates, a removed key denies. - **The privacy-preserving four-class denial contract** (`DenialClass`, `FI-INV-13`) with the byte-exact Nostr text, HTTP status, body, `Content-Type`, and `WWW-Authenticate` values fixed by the spec's rejection table. An unreadable required current dependency maps to `authorization_unavailable`/503, never to rejected evidence, and rejected evidence never masquerades as a 503 at either end of the pipeline: all bounded, dependency-independent checks (compact structure, header, signature shape, policy, algorithm, token class) precede key-source lookup, and all offline validation (token-class, key, signature, audience, claims, time) completes before any status-witness deferral. A wrong-`typ` or structurally malformed token, or malformed/invalidly-signed input naming a current-status issuer, therefore denies with `evidence_rejected`/403 rather than being reported as a 503 availability signal. ## Corrections applied to the mined source Mined from the `buzz-auth` verifier core in [#1476](https://github.com/block/buzz/pull/1476) and corrected to the settled spec (the merged `docs/nips/NIP-FI*.md`, [#5946](https://github.com/block/buzz/pull/5946)), which settled after #1476 was written: - Token-class selection with exact `typ` enforcement. Two classes are offered: `at+jwt` and `nip-fi+jwt`. There is deliberately no generic/absent-`typ` "named compatibility" class: it cannot be proven disjoint from an OIDC ID token by claim presence alone (an issuer can mint an ID token carrying `client_id`), and the only authenticated discriminator is `typ`, which such a mode declines to constrain. - OIDC ID-token denial — denies even when `iss`, `aud`, and `sub` match, via exact `typ` mismatch against every accepted class. - The fixed `nostr_pubkey` claim accepted only as lowercase hex of exactly one 32-byte key; bech32 and other aliases deny. - Resource-owner / client-subject ambiguity denial and required `client_id` for `at+jwt`. - JWK admissibility: a key's `use` and, when present, `key_ops` must authorize signature verification (a key restricted to other operations such as `encrypt` is rejected), and the selected JOSE algorithm is bound to the key's required family and curve (ES256↔EC/P-256, ES384↔EC/P-384, EdDSA↔OKP/Ed25519, RS/PS↔RSA). The JWK `alg` is advisory; the actual key material is what signs, so a JWK declaring a matching `alg` over mismatched material (a different family or curve) is rejected before signature verification. - Spec-exact time arithmetic (`now < exp`, `iat <= now + skew`, `now < iat + maximum_assertion_age`, equality at expiry is expired). `exp`/`iat`/`nbf` accept finite integer or fractional RFC 7519 `NumericDate` values with checked, overflow-safe conversion; non-finite and out-of-range values deny. ## Verification In-crate tests in `crates/buzz-auth/src/nip_fi/verifier/tests.rs` sign real ES256 assertions against a fixed test key and cover: the happy path, exact-wire-text for all four denial classes, deterministic and semantic contract IDs, canonicalization invariance, token-class enforcement including ID-token denial, JWK `key_ops` rejection, `nostr_pubkey` hex handling, time bounds, and multi-issuer selection (same subject across distinct issuers yields distinct identities and policy IDs). They also cover the round-3 contracts: the key-set bound (oversized rejected, at-bound accepted, empty rejected), fixed-`sub` identity (identity is `sub` not a configured `email`; a token without `sub` denies), offline-before-deferral (invalid-signature, wrong-audience, malformed-claim, and expired under a current-status issuer each deny 403/`evidence_rejected`), and the revalidation contracts (dependencies carry the deadline and exact JWS; a retained key revalidates, a removed key denies). And the round-4 contracts: algorithm↔key-material binding, covered exactly per accepted algorithm (a table-driven matrix asserts every policy-acceptable algorithm — ES256, ES384, EdDSA, RS256/384/512, PS256/384/512 — matches only its required family/curve and rejects every other, so each mapping mutation fails individually; and an ES256 token against P-384, RSA, and Ed25519 material each deny `InvalidKey`); malformed evidence classified before key lookup (wrong-`typ`, two-segment, four-segment, empty-signature, and non-base64url-signature tokens against an empty source deny 403 not 503); `maximum_status_age` inapplicable under offline-jwt rejected at construction while current-status still requires it; and fractional `NumericDate` (finite fractional `iat`/`exp`/`nbf` within bounds verify, non-finite and out-of-range deny). Compile-fail doctests guard the sealed authority seam (`AssertionKeySet::new`, `IssuerKeySource`) and the absence of the named-compatibility token class. ## Notes - `Co-authored-by` attribution is preserved for the mined author. The #1476 `buzz-auth` commits are authored by Cea Stapleton Cordasco (the salvage map records #1476 under Franco; the git history on that PR is Cea's — surfacing for the attribution/closure record). - Amends `docs/nips/NIP-FI.md` to remove the "named compatibility access token" class and its `FI-TRACE-TOKEN-CLASS` oracle reference, so the normative spec matches the two-class root implementation (a generic/absent `typ` cannot be proven disjoint from an OIDC ID token). Removal-only, no neighbor redesign; a `docs/nips/` grep confirms no dangling cross-reference to the class remains. - Adds `jsonwebtoken 10.4.0` (`aws_lc_rs`) as a workspace dependency. Dependencies: none. --------- Signed-off-by: Will Pfleger <pfleger.will@gmail.com> Signed-off-by: Duncan <dcfd242e557282d7a1e2cf2e6877522682f1e5c6156dc92ca7d90eaedd3b0f95@buzz.block.builderlab.xyz> Co-authored-by: Cea Stapleton Cordasco <261786559+cea@users.noreply.github.com> Co-authored-by: Duncan <dcfd242e557282d7a1e2cf2e6877522682f1e5c6156dc92ca7d90eaedd3b0f95@buzz.block.builderlab.xyz> |
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Tyler
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d97780b477 |
docs(nips): comprehensive NIP-FI — core + claimable profiles (EDGE/LIFECYCLE/DELEG/CONF) (#5946)
## What Comprehensive NIP-FI against `main`: one normative core plus four separately claimable profiles, replacing the single-document structure of #3726 (which was based on #1485's branch, not `main`). Six documents, 1,975 lines, docs only. - **`NIP-FI.md` (core, 632 lines)** — issuer-qualified identity `(iss, sub)`, independent Nostr proof, client-attached assertion, partial bijection with durable tombstones, atomic final admission, bounded leases, private denials with a closed response vocabulary, retire/revoke/rotate, two contract identities (`assertion_policy_id`, `transport_contract_id`), per-policy `skew` / `maximum_assertion_age` / `maximum_status_age` with missing configuration denying, a closed token-class rule (`at+jwt`, `nip-fi+jwt`, named compatibility; ID tokens always deny), declared freshness class (`offline-jwt` | `current-status`), server-declared body authorization relevance (NIP-98 payload-binding fix, including a `payload` tag on an irrelevant-body operation), BCP 14, "equivalent" defined over identity / bounds / provenance classes, a compact non-normative worked wire example, and a non-normative comparison with DPoP, mTLS-bound tokens, and HTTP Message Signatures. FI-INV-01..16 are normative core text. The behavioral-oracle table lists exactly 30 oracle IDs, one per row, with no shorthand. - **`NIP-FI-EDGE.md`** — trusted-edge surface: the `trusted-proxy-hmac-v2` envelope + canonicalization, or a private authenticated-edge adapter under a reviewed contract; `authorization_domain_id` derivation (exact 16 RFC 9562 UUID bytes); `proof_transport_code` registry (0x01 NIP-42, 0x02 NIP-98; 0x03 Git smart-HTTP and 0x04 Blossom reserved pending their transport contracts; 0x05–0x7f unassigned pending published stable specifications) + extension procedure; body-acquisition bounds; three normative test vectors. An independent Nostr proof (the NIP-98 event in `Authorization`, which reaches the verifier byte-identical, or the NIP-42 event after connect) is the only decision input outside the MAC; absent or incomplete provenance on an edge-required route is `missing_evidence`, present-but-failing provenance is `evidence_rejected`. Header-trust-without-provenance is nonconformant. - **`NIP-FI-LIFECYCLE.md`** — provision / disable / re-enable / administrative expiry (`binding_not_after`) / pending-replacement lineage, one conformance trace per privileged transition; every binding-creating transition declares whether it continues or establishes a grant; a private-condition table for CONF enumeration agreement. - **`NIP-FI-DELEG.md`** — delegated agents; explicit temporal boundaries matching core's inclusive-`nbf`/exclusive-`exp` idiom, with the delegated `skew` configured by this profile; lease deadline anchored to the lease issue instant; strict path separation — a delegated request carries no assertion or provenance field, so it cannot traverse an edge-provenance route and uses ingress on which NIP-FI-EDGE is not required. - **`NIP-FI-CONF.md`** — conformance evidence: an immutable claim tuple including the governing document revision and exit fixture digest; the complete 16-row denial-fixture enumeration with three mechanical enumeration-agreement checks; mutation adequacy with a countable denominator — one retained killed mutant per literal oracle-table row (30 core + 6 EDGE + 11 LIFECYCLE + 7 DELEG + 4 CONF = 58), rows selected structurally by their first cell, never by section title, with the release gate and CONF's own oracle rows stated in the same listed-oracle terms and a mutant defined for CONF's own report- and suite-subject oracles; an interoperability exit test compared over signing inputs (per-transport NIP-01 serialization for the NIP-98 and NIP-42 proofs; decoded protected header and claims as JSON values for the assertion), with a shared exit fixture pinning complete pre-signature header/claim JSON and complete unsigned event fields for both transports, and mandatory negative controls. `FI-CONF-INTEROP-EXIT` is `deferred` with reason `no-independent-implementation` until a second independent implementation exists; the canonical fixture is editor-authored at `docs/nips/fixtures/nip-fi-conf-exit.json` and is **not in this PR** — until it is published a claim records `pending-canonical-fixture`, valid only while the exit test is deferred. Explicit not-applicable dispositions, including `offline-jwt` deployments for the two current-status oracles and absence of a revocation-bounded external capability projection for `FI-TRACE-CAPABILITY-REVOCATION`. - **`NIP-FI-MODEL.md`** — non-normative companion; defines no requirement or conformance claim and is not claimable. ## Why The prior draft rated 9 (soundness) / 6 (minimalness) / 7 (elegance) / 7 (correctness) in adversarial + comparative review. This restructure keeps the two-invariant spine untouched, makes everything else a claimable profile, and collapses five stacked versioning mechanisms into two contract identities. Mutation adequacy counts one mutant per literal oracle-table row — a set two implementers enumerate identically — instead of "each normative requirement," which had four defensible readings. Resolved product calls (owner-approved): 1. Enrollment/denial posture is private — boolean enrollment discovery, TOFU extension claim not self-advertised, `key_mismatch → authorization_denied` joins the denial anonymity set, and replayed evidence is classed `authorization_denied` so resubmission reveals nothing about commit. 2. Revocation honesty — only `current-status` deployments may advertise an unconditional residual-revocation bound; `offline-jwt` advertises unbounded/unknown. Access tokens keep RFC 9068 `at+jwt`; `nip-fi+jwt` is reserved for a separately minted Buzz assertion. ## Acceptance bar - Nothing in core is deletable without losing a stated core guarantee. - From the core document plus the CONF exit fixture, a second implementer can produce a valid request equal over the request compared object (signing inputs), and a byte-exact public denial per class — no reference implementation. - Every oracle-table row ships a retained killed mutant satisfying only the entry it was selected for. - Both deployment profiles (trusted proxy = EDGE, client-held OIDC = core client-attached) pass the same lifecycle conformance suite. ## Status Ready at head |