Cause: ReturnError only writes the response and never aborts the gin
chain; RequirePermission (token error) and WhitelistIPMiddleware (invalid
client IP) returned after ReturnError without ctx.Abort(), so the route
handler still ran after the rejection.
Fix: ctx.Abort() after ReturnError at both sites (and, for clarity, on the
ValidateHandler body-check path, which validateRequestBody already
aborted). RequirePermission now answers a bad token with 401 instead of
500. ReturnError stays non-aborting (documented): handlers such as
ControlHost call it from helpers and then test ctx.IsAborted(), so a
global abort would change handler flows, and it adds nothing in handlers.
Tests: TestRequirePermission_AbortsOnInvalidToken,
TestWhitelistIPMiddleware_AbortsOnFailure.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
