The #733 miss budget (MissBurst / MissRefillPerSecond) was process-wide, because
the impersonation seam did not carry the client's address, so one noisy client
could drain it for everybody while the known-id set was unavailable.
- IOpcUaUserAuthenticator gains AuthenticateUserNameAsync(username, password,
IPEndPoint? remoteEndpoint, ct) (default: ignore it and delegate); the server
calls it. IApiKeyStore gains the matching FindAsync(..., IPAddress?, ...).
- The SDK (1.5.378) exposes no client address publicly. SecureChannelRemoteEndpoint
reads it from the TCP listener's private channel map by reflection (through the
protected TransportListeners, exposed by OtOpcUaSdkServer), keyed by the
session's secure channel id. Fail-soft: null => process-wide accounting only.
- BoundedApiKeyStore charges a miss to the client's own bucket (keyed by IP
address) and then to the process-wide one, which stays as the backstop. A
refusal by either takes from neither; a hit refunds both. New options
Security:ApiKeys:MissBurstPerEndpoint (10) / MissRefillPerSecondPerEndpoint (2),
0 disables; telemetry outcome endpoint_miss_budget. At most 4096 addresses are
tracked; idle buckets are pruned and an address beyond the cap is charged
process-wide only.
Tests: BoundedApiKeyStorePerEndpointTests (noisy client vs quiet one, process-wide
backstop, refund + refill, off switch, authenticator forwards the address) and
over the wire ApiKeyMissBudgetPerEndpointTests (activation hands the authenticator
the loopback endpoint; real authenticator + bounded store refuse a client's 3rd
and 4th unknown key without a store read). Each new behaviour test fails with its
fix mutated out. Host.Tests 224/0, OpcUaServer.Tests 1019/1 (the one failure is the
wall-clock NodeManagerLockTimeBenchmarkTests under suite load; passes alone).
Docs: security.md.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV
Joseph Doherty