- Spec: status → Implemented, fix PATCH peer as new (not pre-existing),
correct API paths, update component breakdown to match actual structure
- Federation docs: update relay rate limit from 30 to 90 req/min
Prevent malicious peers from forging events attributed to users on other
instances. Every relay event processor now verifies the acting user's
homeInstance (from payload) matches X-Federation-Origin (from HMAC-verified
header) via verifyAttribution(), normalized to bare domain.
- Add verifyAttribution() helper using extractDomain normalization
- Guard all 13 event processors before any user resolution or DB writes
- Add homeInstance to FederationRelayReaction type + outbound payloads
- Replace unnormalized string equality in friend handlers
- Log mismatched values on rejection for debugging
Sliding-window rate limiter (30 req/min per peer origin) on POST
/api/federation/relay, matching the existing accept endpoint pattern.
Returns 429 when exceeded — outbox workers retry with backoff. Check
runs before HMAC verification to avoid wasted computation on floods.
Extract processRelayEvents() from the relay HTTP handler and call it
directly in runInitialSyncForNewPeers(), eliminating the HTTP round-trip
through public DNS that failed on networks without hairpin NAT.
Jannis Braun