TelemetryStreamAuthInterceptor, ConfigServeAuthInterceptor and
LocalDbSyncAuthInterceptor all decided "is a key configured?" with
string.IsNullOrEmpty. A whitespace-only configured value therefore passed
that guard and fell through to the constant-time comparison — where it is
satisfied by a whitespace-only bearer token. The gate would be open to
anyone who guessed a blank credential.
This backports the check the two NEW mesh interceptors already use:
MeshCommandAuthInterceptor (and its central-side clone) validate with
string.IsNullOrWhiteSpace, so the four/five planes now answer the same way
to the same misconfiguration. Nothing else changes — the denial status
codes (PermissionDenied / Unauthenticated / PermissionDenied respectively)
and every denial message are untouched, and no key material is logged.
No deployment configures a whitespace key: the docker-dev rig and
production both set real keys, so this is a fail-closed hardening of an
unreachable-today misconfiguration rather than a live exposure.
Tests: each of the three test files gains a ..._WithBlankKeyConfigured_IsDenied
fact mirroring MeshCommandAuthInterceptorTests.ExecuteMethod_WithBlankPskConfigured_IsDenied
(configured key " ", presented "Bearer "), verified red before the fix.
ConfigServeAuthInterceptor and LocalDbSyncAuthInterceptor also gain the
HasExactlyOnePublicConstructor pin their two siblings already had —
Grpc.AspNetCore silently stops invoking an interceptor with more than one
public constructor, which would disable auth without failing anything.
Claude-Session: https://claude.ai/code/session_014WNM4vjoVksyyBraTXSZE1
Joseph Doherty