The public /auth/login route runs a full-cost bcrypt compare on every
request — including the anti-enumeration dummy-hash compare for an unknown
user — with no bound on how many run at once. A flood of concurrent logins
therefore pins every core in bcrypt, starving the rest of the API.
Cap the simultaneous compares with a small non-blocking concurrency limiter
(a buffered-channel semaphore): a login that cannot take a slot is shed with
429 auth_busy before the compare, rather than piling more work onto the
scheduler. The slot guards only the hash and is released the instant the
compare returns. It is a concurrency cap, not a per-account lockout, so it
never fences out the one admin trying to break-glass in, and the 429 lands
before any credential distinction so it leaks nothing about the username.
The cap follows the existing "zero disables" lever idiom (WakeCooldown,
MaxRunningServers); cmd/felis wires it to the core count (floored at 4).
Add username+password login for Owner/Operator staff accounts on
op.console, the primary web login when Zero Trust is not in front of the
API. Three handlers form the whole surface: login mints a server-side
session cookie, logout revokes it idempotently, and change-password
re-verifies the current password before rotating the hash and clearing
must_change_password.
- Session cookies are HttpOnly+Secure+SameSite=Lax, host-only, stored
server-side as a SHA-256 hash with a 12h TTL.
- Login is anti-enumeration: every failure runs a uniform bcrypt compare
against a dummy hash and returns the same vague error.
- Credential-bearing writes require Content-Type: application/json,
returning 415 otherwise, to close the cross-site form-POST forgery
vector as a belt to the SameSite cookie.
- Local auth fails closed: login is rejected unless local_auth_enabled
is set, so a Zero-Trust-only deployment never accepts a local password.
- Extend the users table with a nullable password_hash and
must_change_password; staff are role=admin rows with a hash, players
are role=user rows with hash NULL.
- /me now reports must_change_password so the panel can force a
first-login change.
Covered by Go unit tests (handlers, content-type guard, anti-enumeration,
forced-change lockdown) and the OpenAPI route-parity gate.
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