fix(auth): bind current local registry and CORS

backend/src/app.ts

@@ -2,7 +2,7 @@ import Fastify, { type FastifyInstance } from "fastify";
 import cors from "@fastify/cors";
 import cookie from "@fastify/cookie";
 import rateLimit from "@fastify/rate-limit";
-import { dirname, join } from "node:path";
+import { join } from "node:path";
 import { tmpdir } from "node:os";
 import type { AppConfig } from "./config.js";
 import { ThtRunner } from "./tht/tht-runner.js";
@@ -10,8 +10,9 @@ import { PiProcessManager } from "./pi/pi-process-manager.js";
 import { SseHub } from "./sse/sse-hub.js";
 import { authenticateSession } from "./auth/auth.js";
 import type { PrincipalContext } from "./auth/principal.js";
-import { createLocalUserRegistry, type LocalUserRegistry } from "./auth/local-registry.js";
-import { createFileAuthSessionStore, type AuthSessionStore } from "./auth/session-store.js";
+import type { LoadedAuthConfig } from "./auth/types.js";
+import { createCurrentLocalUserRegistryResolver, type LocalUserRegistry } from "./auth/local-registry.js";
+import { AuthSessionOperationalError, createFileAuthSessionStore, type AuthSessionStore } from "./auth/session-store.js";
 import { registerAuthRoutes } from "./auth/routes.js";
 import { sessionRoutes } from "./routes/sessions.js";
 import { sqlRoutes } from "./routes/sql.js";
@@ -66,10 +67,20 @@ export function buildApp(config: AppConfig, deps?: BuildAppDeps): FastifyInstanc
     installationId: config.workspaceRegistry.installationId,
   });
 
-  // Allow any origin in dev/e2e; tighten in production via config if needed.
+  const cookieAuth = config.authMode === "local" || config.authMode === "oidc";
   app.register(cors, {
-    origin: true,
-    credentials: true,
+    origin: cookieAuth
+      ? (origin, callback) => {
+        try {
+          const allowed = new URL(config.authentication?.current().value.publicUrl ?? "").origin;
+          const requested = origin === undefined ? undefined : new URL(origin).origin;
+          callback(null, requested === allowed ? allowed : false);
+        } catch {
+          callback(null, false);
+        }
+      }
+      : true,
+    credentials: cookieAuth,
     methods: ["GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"],
   });
   // Cookie parsing and the rate-limit plugin must precede every auth/application route.
@@ -150,22 +161,40 @@ export function buildApp(config: AppConfig, deps?: BuildAppDeps): FastifyInstanc
   const piManagement = deps?.piManagement ?? createPiManagement(config, { listModels });
 
   const maintenanceBarrier = deps?.maintenanceBarrier ?? new MaintenanceBarrier(config.maintenanceFile);
-  const loadedAuthentication = config.authentication?.current();
-  const configuredLocalRegistry = loadedAuthentication?.value.mode === "local"
-    ? createLocalUserRegistry(join(dirname(loadedAuthentication.sourcePath), loadedAuthentication.value.local.usersFile))
+  const localRegistryResolver = deps?.localUserRegistry === undefined
+    ? createCurrentLocalUserRegistryResolver()
     : undefined;
-  const localUserRegistry = deps?.localUserRegistry ?? configuredLocalRegistry;
+  const resolveLocalUserRegistry = (loaded: LoadedAuthConfig) => {
+    return deps?.localUserRegistry ?? localRegistryResolver?.resolve(loaded);
+  };
   const authSessionStore = deps?.authSessionStore ?? (config.authMode === "local" || config.authMode === "oidc"
     ? createFileAuthSessionStore(config.authStateRoot, {
-      currentAuthConfigRevision: () => config.authentication?.current().revision ?? "",
-      findLocalUser: async (subject) => {
-        if (config.authentication?.current().value.mode !== "local") return undefined;
-        const user = await localUserRegistry?.findBySubject(subject);
-        return user === undefined ? undefined : {
-          enabled: user.enabled,
-          authRevision: user.authRevision,
-          roles: user.roles,
-        };
+      currentAuthConfigRevision: () => {
+        try {
+          return config.authentication?.current().revision ?? "";
+        } catch {
+          throw new AuthSessionOperationalError();
+        }
+      },
+      currentLocalUser: async (subject) => {
+        try {
+          const loaded = config.authentication?.current();
+          if (!loaded || loaded.value.mode !== "local") return { revision: "", user: undefined };
+          const registry = resolveLocalUserRegistry(loaded);
+          if (!registry) throw new AuthSessionOperationalError();
+          const user = await registry.findBySubject(subject);
+          return {
+            revision: loaded.revision,
+            user: user === undefined ? undefined : {
+              enabled: user.enabled,
+              authRevision: user.authRevision,
+              roles: user.roles,
+            },
+          };
+        } catch (error) {
+          if (error instanceof AuthSessionOperationalError) throw error;
+          throw new AuthSessionOperationalError();
+        }
       },
     })
     : undefined);
@@ -204,7 +233,8 @@ export function buildApp(config: AppConfig, deps?: BuildAppDeps): FastifyInstanc
     authMode: config.authMode,
     authentication: config.authentication,
     sessionStore: authSessionStore,
-    localUserRegistry,
+    localUserRegistry: deps?.localUserRegistry,
+    resolveLocalUserRegistry,
   });
   sessionRoutes(app, {
     mgr, tht: tht as ThtRunner, hub, getSettings, readiness, listModels, workspaceRegistry,

backend/src/auth/auth.ts

@@ -2,7 +2,7 @@ import type { FastifyRequest, FastifyReply, preHandlerHookHandler } from "fastif
 import { localPrincipal, type PrincipalContext, upstreamPrincipal } from "./principal.js";
 import { rolesToPermissions } from "./config.js";
 import type { AuthenticationConfigProvider, AuthMode, AuthSessionRecord } from "./types.js";
-import type { AuthSessionStore } from "./session-store.js";
+import { AuthSessionOperationalError, type AuthSessionStore } from "./session-store.js";
 import { deriveCsrfToken, csrfTokensEqual } from "./csrf.js";
 import { requireSameOriginOrNonBrowser } from "./authorization.js";
 
@@ -78,7 +78,10 @@ export function authenticateSession(deps: AuthDependencies): preHandlerHookHandl
     try {
       session = await deps.sessionStore.resolve(token);
       if (session) await deps.sessionStore.touch(token);
-    } catch {
+    } catch (error) {
+      if (error instanceof AuthSessionOperationalError) {
+        return reply.code(503).send({ code: "auth_unavailable", error: "Authentication is unavailable" });
+      }
       return authenticationRequired(reply);
     }
     if (!session) return authenticationRequired(reply);
@@ -174,7 +177,11 @@ function singleHeader(value: string | string[] | undefined): string | false | un
 
 function matchesOrigin(request: FastifyRequest, expectedOrigin: string): boolean {
   const origin = singleHeader(request.headers.origin);
-  if (origin !== expectedOrigin) return false;
+  try {
+    if (origin === undefined || origin === false || new URL(origin).origin !== expectedOrigin) return false;
+  } catch {
+    return false;
+  }
   const fetchSite = singleHeader(request.headers["sec-fetch-site"]);
   return fetchSite === undefined || fetchSite === "same-origin";
 }

backend/src/auth/local-registry.ts

@@ -8,11 +8,11 @@ import {
   realpathSync,
 } from "node:fs";
 import type { Stats } from "node:fs";
-import { dirname, isAbsolute, normalize } from "node:path";
+import { dirname, isAbsolute, join, normalize } from "node:path";
 import { parseDocument } from "yaml";
 import { z } from "zod";
 import { isValidPasswordHash, verifyPassword, verifyWithDummy } from "./password.js";
-import type { Role } from "./types.js";
+import type { LoadedAuthConfig, Role } from "./types.js";
 
 const MAX_USERS_YAML_BYTES = 1 << 20;
 const USERNAME_PATTERN = /^[A-Za-z0-9][A-Za-z0-9._@-]{2,63}$/;
@@ -37,6 +37,11 @@ export interface LocalUserRegistry {
   verify(user: LocalUserRecord | undefined, password: string): Promise<boolean>;
 }
 
+/** Keeps only the registry named by the current coherent authentication-config snapshot. */
+export interface CurrentLocalUserRegistryResolver {
+  resolve(loaded: LoadedAuthConfig): LocalUserRegistry | undefined;
+}
+
 interface FileIdentity {
   dev: number;
   ino: number;
@@ -253,3 +258,17 @@ export function createLocalUserRegistry(usersPath: string): LocalUserRegistry {
     },
   };
 }
+
+export function createCurrentLocalUserRegistryResolver(): CurrentLocalUserRegistryResolver {
+  let current: { usersPath: string; registry: LocalUserRegistry } | undefined;
+  return {
+    resolve(loaded: LoadedAuthConfig): LocalUserRegistry | undefined {
+      if (loaded.value.mode !== "local") return undefined;
+      const usersPath = join(dirname(loaded.sourcePath), loaded.value.local.usersFile);
+      if (current?.usersPath === usersPath) return current.registry;
+      const registry = createLocalUserRegistry(usersPath);
+      current = { usersPath, registry };
+      return registry;
+    },
+  };
+}

backend/src/auth/password.ts

@@ -1,13 +1,11 @@
 import { argon2, timingSafeEqual } from "node:crypto";
 
 const MAXIMUM_PHC_BYTES = 256;
-const MAXIMUM_MEMORY_KIB = 256 * 1024;
-const MAXIMUM_PASSES = 10;
-const MAXIMUM_PARALLELISM = 4;
-const MINIMUM_SALT_BYTES = 16;
-const MAXIMUM_SALT_BYTES = 64;
-const MINIMUM_KEY_BYTES = 16;
-const MAXIMUM_KEY_BYTES = 64;
+const ARGON2_MEMORY_KIB = 65_536;
+const ARGON2_PASSES = 3;
+const ARGON2_PARALLELISM = 1;
+const ARGON2_SALT_BYTES = 16;
+const ARGON2_KEY_BYTES = 32;
 const MINIMUM_PASSWORD_BYTES = 12;
 const MAXIMUM_PASSWORD_BYTES = 1024;
 
@@ -19,6 +17,13 @@ interface Argon2Parameters {
   digest: Buffer;
 }
 
+/** Internal-only signal for unavailable native Argon2 work; never expose its cause. */
+export class LocalPasswordVerificationError extends Error {
+  constructor() {
+    super("local_password_verification_failed");
+  }
+}
+
 function parseDecimal(value: string, maximum: number): number | undefined {
   if (!/^\d+$/.test(value) || (value.length > 1 && value[0] === "0") || value.length > 10) return undefined;
   const parsed = Number(value);
@@ -46,13 +51,13 @@ function parsePHC(encoded: string): Argon2Parameters | undefined {
 
   const parameterParts = parts[3].split(",");
   if (parameterParts.length !== 3 || !parameterParts[0].startsWith("m=") || !parameterParts[1].startsWith("t=") || !parameterParts[2].startsWith("p=")) return undefined;
-  const memory = parseDecimal(parameterParts[0].slice(2), MAXIMUM_MEMORY_KIB);
-  const passes = parseDecimal(parameterParts[1].slice(2), MAXIMUM_PASSES);
-  const parallelism = parseDecimal(parameterParts[2].slice(2), MAXIMUM_PARALLELISM);
-  if (memory === undefined || memory < 8 || passes === undefined || passes === 0 || parallelism === undefined || parallelism === 0 || memory < 8 * parallelism) return undefined;
+  const memory = parseDecimal(parameterParts[0].slice(2), ARGON2_MEMORY_KIB);
+  const passes = parseDecimal(parameterParts[1].slice(2), ARGON2_PASSES);
+  const parallelism = parseDecimal(parameterParts[2].slice(2), ARGON2_PARALLELISM);
+  if (memory !== ARGON2_MEMORY_KIB || passes !== ARGON2_PASSES || parallelism !== ARGON2_PARALLELISM) return undefined;
 
-  const salt = decodeRawBase64(parts[4], MINIMUM_SALT_BYTES, MAXIMUM_SALT_BYTES);
-  const digest = decodeRawBase64(parts[5], MINIMUM_KEY_BYTES, MAXIMUM_KEY_BYTES);
+  const salt = decodeRawBase64(parts[4], ARGON2_SALT_BYTES, ARGON2_SALT_BYTES);
+  const digest = decodeRawBase64(parts[5], ARGON2_KEY_BYTES, ARGON2_KEY_BYTES);
   if (!salt || !digest) {
     salt?.fill(0);
     digest?.fill(0);
@@ -92,6 +97,7 @@ function deriveArgon2(message: Buffer, parameters: Argon2Parameters): Promise<Bu
       }
       settled = true;
       if (error || !derived) {
+        derived?.fill(0);
         reject(error ?? new Error("argon2_failed"));
         return;
       }
@@ -135,7 +141,7 @@ export async function verifyPassword(password: string, encoded: string): Promise
     derived = await deriveArgon2(message, parameters);
     return derived.length === parameters.digest.length && timingSafeEqual(derived, parameters.digest);
   } catch {
-    return false;
+    throw new LocalPasswordVerificationError();
   } finally {
     message.fill(0);
     derived?.fill(0);

backend/src/auth/routes.ts

@@ -1,12 +1,13 @@
 import type { FastifyInstance, FastifyReply, FastifyRequest } from "fastify";
 import { randomBytes } from "node:crypto";
-import type { AuthenticationConfigProvider } from "./types.js";
+import type { AuthenticationConfigProvider, LoadedAuthConfig } from "./types.js";
 import type { LocalUserRecord, LocalUserRegistry } from "./local-registry.js";
 import type { AuthSessionStore } from "./session-store.js";
 import { rolesToPermissions } from "./config.js";
 import { getPrincipal, requireExactOrigin, sessionCookieName } from "./auth.js";
 import { requirePermission, isPrincipalContext } from "./authorization.js";
 import { deriveCsrfToken } from "./csrf.js";
+import { verifyWithDummy } from "./password.js";
 
 const TEN_MINUTES_MS = 10 * 60 * 1000;
 const REMEMBER_COOKIE_SECONDS = 2_592_000;
@@ -18,7 +19,9 @@ export interface AuthRouteDependencies {
   authMode: "local" | "oidc" | "upstream" | "none" | "mock";
   authentication?: AuthenticationConfigProvider;
   sessionStore?: AuthSessionStore;
+  /** Test-only compatibility seam; production resolves from each loaded config snapshot. */
   localUserRegistry?: LocalUserRegistry;
+  resolveLocalUserRegistry?: (loaded: LoadedAuthConfig) => LocalUserRegistry | undefined;
 }
 
 interface LoginPayload {
@@ -90,6 +93,23 @@ class VerificationGate {
   }
 }
 
+async function unavailableAfterDummy(
+  gate: VerificationGate,
+  password: string,
+  reply: FastifyReply,
+): Promise<FastifyReply> {
+  try {
+    const completed = await gate.run(async () => {
+      await verifyWithDummy(password);
+      return true;
+    });
+    if (completed === undefined) return loginLimited(reply);
+  } catch {
+    // Preserve the sanitized operational outcome below.
+  }
+  return unavailable(reply);
+}
+
 export function registerAuthRoutes(app: FastifyInstance, deps: AuthRouteDependencies): void {
   const limiter = new LoginFailureLimiter();
   const verificationGate = new VerificationGate();
@@ -105,25 +125,29 @@ export function registerAuthRoutes(app: FastifyInstance, deps: AuthRouteDependen
 
   app.post("/auth/local/login", async (request, reply) => {
     const configured = currentLocalConfig(deps);
-    if (!configured || !deps.localUserRegistry || !deps.sessionStore) return unavailable(reply);
+    if (configured.kind === "unavailable") {
+      return unavailableAfterDummy(verificationGate, argon2SafePassword(loginPayload(request).password), reply);
+    }
+    if (configured.kind !== "local" || !deps.sessionStore) return unavailable(reply);
     const originCheck = requireExactOrigin(request, reply, configured.origin);
     if (originCheck !== true) return originCheck;
 
     const payload = loginPayload(request);
+    const safePassword = argon2SafePassword(payload.password);
     const normalizedUsername = payload.username.replace(/[A-Z]/g, (character) => character.toLowerCase());
     const sourceAddress = boundedAddress(request.ip);
     if (limiter.isLimited(normalizedUsername, sourceAddress)) return loginLimited(reply);
 
     let user: LocalUserRecord | undefined;
     try {
-      if (payload.username.length > 0) user = await deps.localUserRegistry.findByUsername(payload.username);
+      if (payload.username.length > 0) user = await configured.registry.findByUsername(payload.username);
     } catch {
-      user = undefined;
+      return unavailableAfterDummy(verificationGate, safePassword, reply);
     }
     let verified: boolean | undefined;
     try {
       verified = await verificationGate.run(async () =>
-        deps.localUserRegistry!.verify(user, argon2SafePassword(payload.password)));
+        configured.registry.verify(user, safePassword));
     } catch {
       return unavailable(reply);
     }
@@ -177,7 +201,18 @@ export function registerAuthRoutes(app: FastifyInstance, deps: AuthRouteDependen
     if (!isPrincipalContext(principal)) return principal;
     const session = request.authSession;
     const token = request.authSessionToken;
-    if (!session || !token) return unavailable(reply);
+    if (!session || !token) {
+      return {
+        issuer: principal.issuer,
+        subject: principal.subject,
+        ...(principal.displayName === undefined ? {} : { displayName: principal.displayName }),
+        roles: principal.roles,
+        permissions: principal.permissions,
+        isAdmin: principal.isAdmin,
+        csrfToken: null,
+        session: null,
+      };
+    }
     try {
       return {
         issuer: principal.issuer,
@@ -200,24 +235,33 @@ export function registerAuthRoutes(app: FastifyInstance, deps: AuthRouteDependen
   });
 }
 
-function currentLocalConfig(deps: AuthRouteDependencies): {
+function currentLocalConfig(deps: AuthRouteDependencies):
+  | {
   revision: string;
   origin: string;
   secure: boolean;
   session: { regularTtlSeconds: number; regularIdleSeconds: number; rememberTtlSeconds: number; rememberIdleSeconds: number };
-} | undefined {
+  registry: LocalUserRegistry;
+  kind: "local";
+}
+  | { kind: "not_local" }
+  | { kind: "unavailable" } {
   try {
     const loaded = deps.authentication?.current();
-    if (!loaded || loaded.value.mode !== "local") return undefined;
+    if (!loaded || loaded.value.mode !== "local") return { kind: "not_local" };
+    const registry = deps.resolveLocalUserRegistry?.(loaded) ?? deps.localUserRegistry;
+    if (!registry) return { kind: "unavailable" };
     const url = new URL(loaded.value.publicUrl);
     return {
+      kind: "local",
       revision: loaded.revision,
       origin: url.origin,
       secure: url.protocol === "https:",
       session: loaded.value.session,
+      registry,
     };
   } catch {
-    return undefined;
+    return { kind: "unavailable" };
   }
 }
 

backend/src/auth/session-store.ts

@@ -81,13 +81,26 @@ export interface LocalSessionUser {
   roles: readonly Role[];
 }
 
+export interface CurrentLocalSessionUser {
+  revision: string;
+  user: LocalSessionUser | undefined;
+}
+
+/** Operational validity-source failures must not masquerade as revoked credentials. */
+export class AuthSessionOperationalError extends Error {
+  constructor() {
+    super("auth_session_operational_error");
+  }
+}
+
 /**
  * The route layer supplies the current installation revision and local-registry lookup.
  * Supplying this hook makes every resolve an authorization-generation check.
  */
 export interface AuthSessionValidity {
   currentAuthConfigRevision(): string | Promise<string>;
-  findLocalUser(subject: string): LocalSessionUser | undefined | Promise<LocalSessionUser | undefined>;
+  findLocalUser?(subject: string): LocalSessionUser | undefined | Promise<LocalSessionUser | undefined>;
+  currentLocalUser?(subject: string): CurrentLocalSessionUser | Promise<CurrentLocalSessionUser>;
 }
 
 export interface AuthSessionStore {
@@ -682,10 +695,15 @@ async function recordIsCurrent(record: AuthSessionRecord, validity: AuthSessionV
   // A root-only store remains useful for creation/diagnostics, but is intentionally incapable
   // of authenticating a principal. Task 8 must supply config and local-registry dependencies.
   if (!validity) return false;
+  if (record.method === "local" && validity.currentLocalUser) {
+    const current = await validity.currentLocalUser(record.subject);
+    return typeof current.revision === "string" && current.revision === record.authConfigRevision
+      && validLocalUser(current.user, record);
+  }
   const revision = await validity.currentAuthConfigRevision();
   if (typeof revision !== "string" || revision !== record.authConfigRevision) return false;
   if (record.method !== "local") return true;
-  return validLocalUser(await validity.findLocalUser(record.subject), record);
+  return validity.findLocalUser === undefined ? false : validLocalUser(await validity.findLocalUser(record.subject), record);
 }
 
 const locks = new Map<string, Promise<void>>();
@@ -799,7 +817,8 @@ export function createFileAuthSessionStore(
         }
         try {
           if (await recordIsCurrent(record, validity)) return record;
-        } catch {
+        } catch (error) {
+          if (error instanceof AuthSessionOperationalError) throw error;
           await bridge.remove(root, "sessions", filename);
           throw invalid();
         }
@@ -815,7 +834,8 @@ export function createFileAuthSessionStore(
       }
       try {
         if (await recordIsCurrent(trusted.value, validity)) return trusted.value;
-      } catch {
+      } catch (error) {
+        if (error instanceof AuthSessionOperationalError) throw error;
         removeTrusted(directories.sessions, filename, trusted.identity);
         throw invalid();
       }

backend/src/routes/sessions.ts

@@ -698,16 +698,29 @@ export function sessionRoutes(
       if (!await authorize(principal, id)) return reply.code(404).send({ error: "session not found" });
     } catch (error) { return lifecycleFailure(reply, error); }
     const rt = d.mgr.get(id);
-    // Add CORS headers manually: reply.raw.writeHead bypasses Fastify's onSend hooks
-    // (where @fastify/cors injects headers), so we must set them explicitly here.
-    const origin = (req.headers.origin as string | undefined) ?? "*";
+    // reply.raw.writeHead bypasses Fastify's CORS hook. Only a cookie-authenticated request
+    // from the exact configured public origin receives credentialed SSE CORS headers.
+    const origin = typeof req.headers.origin === "string" ? req.headers.origin : undefined;
+    let isConfiguredOrigin = false;
+    try {
+      isConfiguredOrigin = req.authPublicOrigin !== undefined
+        && origin !== undefined
+        && new URL(origin).origin === req.authPublicOrigin;
+    } catch {
+      isConfiguredOrigin = false;
+    }
+    const corsHeaders = isConfiguredOrigin
+      ? {
+        "Access-Control-Allow-Origin": req.authPublicOrigin,
+        "Access-Control-Allow-Credentials": "true",
+      }
+      : {};
     reply.raw.writeHead(200, {
       "Content-Type": "text/event-stream",
       "Cache-Control": "no-cache",
       "X-Accel-Buffering": "no",
       Connection: "keep-alive",
-      "Access-Control-Allow-Origin": origin,
-      "Access-Control-Allow-Credentials": "true",
+      ...corsHeaders,
     });
     // Send the handshake immediately. Without this, Node waits for the first event body and
     // proxies/clients cannot establish an idle SSE subscription or inspect its headers.

backend/test/auth-cors.test.ts

@@ -0,0 +1,54 @@
+import { afterAll, beforeAll, expect, test } from "vitest";
+import { createLocalAuthFixture, type LocalAuthFixture, localPublicUrl } from "./auth-test-fixtures.js";
+
+let fixture: LocalAuthFixture;
+
+beforeAll(async () => {
+  fixture = await createLocalAuthFixture();
+});
+
+afterAll(async () => {
+  await fixture.close();
+});
+
+test("credentialed CORS permits only the current configured public origin", async () => {
+  const allowedPreflight = await fixture.app.inject({
+    method: "OPTIONS", url: "/me",
+    headers: { origin: localPublicUrl, "access-control-request-method": "GET" },
+  });
+  expect(allowedPreflight.statusCode).toBe(204);
+  expect(allowedPreflight.headers["access-control-allow-origin"]).toBe(localPublicUrl);
+  expect(allowedPreflight.headers["access-control-allow-credentials"]).toBe("true");
+
+  const canonicalPreflight = await fixture.app.inject({
+    method: "OPTIONS", url: "/me",
+    headers: { origin: "HTTP://127.0.0.1:8787", "access-control-request-method": "GET" },
+  });
+  expect(canonicalPreflight.statusCode).toBe(204);
+  expect(canonicalPreflight.headers["access-control-allow-origin"]).toBe(localPublicUrl);
+
+  const attackerPreflight = await fixture.app.inject({
+    method: "OPTIONS", url: "/me",
+    headers: { origin: "https://attacker.example.test", "access-control-request-method": "GET" },
+  });
+  expect(attackerPreflight.headers["access-control-allow-origin"]).toBeUndefined();
+  expect(attackerPreflight.headers["access-control-allow-credentials"]).toBeUndefined();
+
+  const allowed = await fixture.app.inject({
+    method: "GET", url: "/me", headers: { cookie: fixture.cookie, origin: localPublicUrl },
+  });
+  expect(allowed.statusCode).toBe(200);
+  expect(allowed.headers["access-control-allow-origin"]).toBe(localPublicUrl);
+  expect(allowed.headers["access-control-allow-credentials"]).toBe("true");
+
+  const attacker = await fixture.app.inject({
+    method: "GET", url: "/me", headers: { cookie: fixture.cookie, origin: "https://attacker.example.test" },
+  });
+  expect(attacker.statusCode).toBe(200);
+  expect(attacker.headers["access-control-allow-origin"]).toBeUndefined();
+  expect(attacker.headers["access-control-allow-credentials"]).toBeUndefined();
+
+  const nonBrowser = await fixture.app.inject({ method: "GET", url: "/me", headers: { cookie: fixture.cookie } });
+  expect(nonBrowser.statusCode).toBe(200);
+  expect(nonBrowser.headers["access-control-allow-origin"]).toBeUndefined();
+});

backend/test/auth-dynamic-registry.test.ts

@@ -0,0 +1,88 @@
+import { afterEach, expect, test } from "vitest";
+import { chmodSync, mkdtempSync, readFileSync, realpathSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { stringify } from "yaml";
+import { buildApp, type AppWithAuthSessionStore } from "../src/app.js";
+import { loadAuthenticationConfig } from "../src/auth/config.js";
+import { loadConfig } from "../src/config.js";
+
+const password = "correct horse battery staple";
+const passwordHash = "$argon2id$v=19$m=65536,t=3,p=1$AAECAwQFBgcICQoLDA0ODw$DRo8ZSPI8G5OCvnFFapbVEjP69aDjy1Sw9i2743cPC4";
+const userA = { id: "6ba7b810-9dad-4ed1-80b4-00c04fd430c8", username: "AdminA" };
+const userB = { id: "6ba7b811-9dad-4ed1-80b4-00c04fd430c8", username: "AdminB" };
+const publicUrl = "http://127.0.0.1:8787";
+const cleanups: Array<() => Promise<void>> = [];
+
+afterEach(async () => {
+  for (const cleanup of cleanups.splice(0).reverse()) await cleanup();
+});
+
+function usersYaml(user: typeof userA): string {
+  return [
+    "version: 1", "users:", `  - id: ${user.id}`, `    username: ${user.username}`,
+    `    passwordHash: ${passwordHash}`, "    roles:", "      - admin", "    enabled: true", "    authRevision: 1", "",
+  ].join("\n");
+}
+
+function configYaml(usersFile: string) {
+  return stringify({ version: 1, mode: "local", publicUrl, local: { usersFile } });
+}
+
+function cookiePair(response: { headers: Record<string, string | string[] | undefined> }): string {
+  const header = response.headers["set-cookie"];
+  const first = Array.isArray(header) ? header[0] : header;
+  return first?.split(";", 1)[0] ?? "";
+}
+
+test("each login and session resolve uses the current config snapshot users file", async () => {
+  const directory = mkdtempSync(join(realpathSync(tmpdir()), "thothii-auth-dynamic-"));
+  chmodSync(directory, 0o700);
+  const authFile = join(directory, "auth.yaml");
+  const usersAFile = join(directory, "users-a.yaml");
+  const usersBFile = join(directory, "users-bbbbb.yaml");
+  writeFileSync(usersAFile, usersYaml(userA), { encoding: "utf8", mode: 0o600 });
+  writeFileSync(usersBFile, usersYaml(userB), { encoding: "utf8", mode: 0o600 });
+  writeFileSync(authFile, configYaml("users-a.yaml"), { encoding: "utf8", mode: 0o600 });
+  chmodSync(authFile, 0o600);
+  chmodSync(usersAFile, 0o600);
+  chmodSync(usersBFile, 0o600);
+  const app = buildApp(loadConfig({
+    THT_AUTH_CONFIG_FILE: authFile,
+    THT_AUTH_STATE_ROOT: join(directory, "auth-state"),
+    THT_HARNESS_DIR: "/tmp/h",
+  }));
+  cleanups.push(async () => {
+    await app.close();
+    rmSync(directory, { recursive: true, force: true });
+  });
+  const signIn = (username: string) => app.inject({
+    method: "POST", url: "/auth/local/login",
+    headers: { origin: publicUrl, "sec-fetch-site": "same-origin" },
+    payload: { username, password },
+  });
+
+  const first = await signIn(userA.username);
+  expect(first.statusCode).toBe(200);
+  const aCookie = cookiePair(first);
+  expect((await app.inject({ method: "GET", url: "/me", headers: { cookie: aCookie } })).json())
+    .toMatchObject({ subject: userA.id });
+
+  writeFileSync(authFile, configYaml("users-bbbbb.yaml"), { encoding: "utf8", mode: 0o600 });
+  chmodSync(authFile, 0o600);
+  expect(readFileSync(usersAFile, "utf8")).toContain(userA.username);
+
+  const removedUser = await signIn(userA.username);
+  expect(removedUser.statusCode).toBe(401);
+  expect(removedUser.json()).toEqual({ code: "invalid_credentials", error: "Invalid username or password" });
+  expect((await app.inject({ method: "GET", url: "/me", headers: { cookie: aCookie } })).statusCode).toBe(401);
+
+  const second = await signIn(userB.username);
+  expect(second.statusCode).toBe(200);
+  const bCookie = cookiePair(second);
+  expect(await app.inject({ method: "GET", url: "/me", headers: { cookie: bCookie } }).then((response) => response.json()))
+    .toMatchObject({ subject: userB.id });
+  const token = bCookie.split("=", 2)[1] ?? "";
+  const record = await (app as AppWithAuthSessionStore).thothiiAuthSessionStore?.resolve(token);
+  expect(record).toMatchObject({ subject: userB.id, authConfigRevision: loadAuthenticationConfig(authFile).revision });
+});

backend/test/auth-password.test.ts

@@ -9,7 +9,7 @@ vi.mock("node:crypto", async (importOriginal) => {
   return { ...actual, argon2: argon2Spy };
 });
 
-import { verifyPassword } from "../src/auth/password.js";
+import { isValidPasswordHash, verifyPassword } from "../src/auth/password.js";
 
 interface Argon2Vector {
   password: string;
@@ -76,6 +76,7 @@ describe("local Argon2id password verification", () => {
       `$argon2id$v=19$m=65536,t=3,p=5$${salt}$${digest}`,
       `$argon2id$v=19$m=65536,t=3,p=1$${salt}$${"A".repeat(88)}`,
       `$argon2id$v=19$m=65536,t=3,p=1$${salt}=$${digest}`,
+      `$argon2id$v=19$m=8,t=1,p=1$${salt}$${digest}`,
     ];
 
     for (const phc of cases) {
@@ -84,4 +85,24 @@ describe("local Argon2id password verification", () => {
       expect(argon2Spy).not.toHaveBeenCalled();
     }
   });
+
+  test("accepts only the exact Go Argon2id policy in registry PHCs", () => {
+    const [empty, algorithm, version, parameters, salt, digest] = vectors[0].phc.split("$");
+    expect(empty).toBe("");
+    expect(algorithm).toBe("argon2id");
+    expect(version).toBe("v=19");
+    expect(isValidPasswordHash(`$${algorithm}$${version}$m=8,t=1,p=1$${salt}$${digest}`)).toBe(false);
+    expect(isValidPasswordHash(`$${algorithm}$${version}$m=65536,t=1,p=1$${salt}$${digest}`)).toBe(false);
+    expect(isValidPasswordHash(`$${algorithm}$${version}$m=65536,t=3,p=2$${salt}$${digest}`)).toBe(false);
+    expect(isValidPasswordHash(`$${algorithm}$${version}$${parameters}$${salt}$${digest}`)).toBe(true);
+  });
+
+  test("surfaces a sanitized operational error when native Argon2 fails", async () => {
+    argon2Spy.mockImplementationOnce((_algorithm, _parameters, callback) => {
+      callback(new Error("native details must not leave the verifier"));
+    });
+
+    await expect(verifyPassword(vectors[0].password, vectors[0].phc))
+      .rejects.toThrow("local_password_verification_failed");
+  });
 });

backend/test/auth-production-csrf.test.ts

@@ -47,19 +47,30 @@ afterAll(async () => {
 test.each(stateChangingRoutes)(
   "$family $method $url rejects every production CSRF/session-boundary failure before downstream code",
   async ({ method, url }) => {
-    const failures = [
-      fixture.sessionHeaders({ "x-thothii-csrf": undefined }),
-      fixture.sessionHeaders({ "x-thothii-csrf": "malformed" }),
-      fixture.sessionHeaders({ origin: undefined }),
-      fixture.sessionHeaders({ origin: "http://wrong.example.test" }),
-      fixture.sessionHeaders({ "sec-fetch-site": "cross-site" }),
+    const failures: Array<{ expectedStatus: number; headers: Record<string, string> }> = [
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ "x-thothii-csrf": undefined }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ "x-thothii-csrf": "malformed" }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ "x-thothii-csrf": `${fixture.csrfToken}, ${fixture.csrfToken}` }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ "x-thothii-csrf": "x".repeat(4097) }) },
+      { expectedStatus: 401, headers: fixture.sessionHeaders({ cookie: undefined }) },
+      { expectedStatus: 401, headers: fixture.sessionHeaders({ cookie: "thothii_session=not-a-token" }) },
+      { expectedStatus: 401, headers: fixture.sessionHeaders({ cookie: `${fixture.cookie}; ${fixture.cookie}` }) },
+      { expectedStatus: 401, headers: fixture.sessionHeaders({ cookie: `${fixture.cookie}; padding=${"x".repeat(4097)}` }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ origin: undefined }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ origin: "http://wrong.example.test" }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ origin: `${localPublicUrl}, ${localPublicUrl}` }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ origin: `${localPublicUrl}${"x".repeat(4097)}` }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ "sec-fetch-site": "cross-site" }) },
+      { expectedStatus: 403, headers: fixture.sessionHeaders({ "sec-fetch-site": "same-origin, same-origin" }) },
     ];
 
-    for (const headers of failures) {
+    for (const { expectedStatus, headers } of failures) {
       fixture.resetDownstreamHits();
       const response = await fixture.app.inject({ method, url, headers, payload: {} });
-      expect(response.statusCode).toBe(403);
-      expect(response.json()).toEqual({ code: "csrf_failed", error: "Request origin validation failed" });
+      expect(response.statusCode).toBe(expectedStatus);
+      expect(response.json()).toEqual(expectedStatus === 403
+        ? { code: "csrf_failed", error: "Request origin validation failed" }
+        : { code: "authentication_required", error: "Authentication is required" });
       expect(fixture.downstreamHits()).toBe(0);
     }
   },
@@ -78,3 +89,16 @@ test("a valid real local session cookie and derived CSRF token cross the same pr
   expect(fixture.downstreamHits()).toBe(1);
   expect(localPublicUrl).toBe("http://127.0.0.1:8787");
 });
+
+test("a valid control may omit optional Fetch Metadata while retaining its exact Origin and CSRF pair", async () => {
+  fixture.resetDownstreamHits();
+  const response = await fixture.app.inject({
+    method: "PUT",
+    url: "/settings",
+    headers: fixture.sessionHeaders({ "sec-fetch-site": undefined }),
+    payload: {},
+  });
+
+  expect(response.statusCode).toBe(200);
+  expect(fixture.downstreamHits()).toBe(1);
+});

backend/test/auth-routes-local.test.ts

@@ -27,7 +27,7 @@ function localConfig(url = publicUrl) {
 }
 
 function usersYaml(options: { enabled?: boolean; username?: string } = {}): string {
-  return [
+  const users = [
     "version: 1",
     "users:",
     `  - id: ${adminId}`,
@@ -38,8 +38,19 @@ function usersYaml(options: { enabled?: boolean; username?: string } = {}): stri
     "      - admin",
     `    enabled: ${options.enabled ?? true}`,
     "    authRevision: 1",
-    "",
-  ].join("\n");
+  ];
+  if (options.enabled === false) {
+    users.push(
+      "  - id: 6ba7b811-9dad-4ed1-80b4-00c04fd430c8",
+      "    username: BackupAdmin",
+      `    passwordHash: ${passwordHash}`,
+      "    roles:",
+      "      - admin",
+      "    enabled: true",
+      "    authRevision: 1",
+    );
+  }
+  return [...users, ""].join("\n");
 }
 
 function firstSetCookie(response: { headers: Record<string, string | string[] | undefined> }): string {
@@ -401,6 +412,58 @@ test("a verifier failure is sanitized and releases its concurrency permit", asyn
   expect(attempts).toBe(2);
 });
 
+test("operational registry failures do dummy work, return 503, and never consume login-failure capacity", async () => {
+  let available = false;
+  let verificationCalls = 0;
+  const user = {
+    id: adminId, username: "Admin", normalizedUsername: "admin", displayName: "Local administrator",
+    passwordHash, roles: ["admin"], enabled: true, authRevision: 1,
+  };
+  const { app } = await createLocalApp({
+    registry: {
+      findByUsername: async () => {
+        if (!available) throw new Error("registry file is unavailable");
+        return user;
+      },
+      findBySubject: async () => user,
+      verify: async () => {
+        verificationCalls += 1;
+        return false;
+      },
+    },
+  });
+
+  for (let attempt = 0; attempt < 11; attempt += 1) {
+    const response = await login(app);
+    expect(response.statusCode).toBe(503);
+    expect(response.json()).toEqual({ code: "auth_unavailable", error: "Authentication is unavailable" });
+  }
+  expect(verificationCalls).toBe(0);
+
+  available = true;
+  for (let attempt = 0; attempt < 10; attempt += 1) expect((await login(app)).statusCode).toBe(401);
+  expect((await login(app)).statusCode).toBe(429);
+});
+
+test("operational config failures return 503 and never consume login-failure capacity", async () => {
+  const { app, authConfigFile } = await createLocalApp();
+  writeFileSync(authConfigFile, "version: 1\nmode: unsupported\n", { encoding: "utf8", mode: 0o600 });
+  chmodSync(authConfigFile, 0o600);
+
+  for (let attempt = 0; attempt < 11; attempt += 1) {
+    const response = await login(app);
+    expect(response.statusCode).toBe(503);
+    expect(response.json()).toEqual({ code: "auth_unavailable", error: "Authentication is unavailable" });
+  }
+
+  writeFileSync(authConfigFile, stringify(localConfig()), { encoding: "utf8", mode: 0o600 });
+  chmodSync(authConfigFile, 0o600);
+  for (let attempt = 0; attempt < 10; attempt += 1) {
+    expect((await login(app, { password: `${password}!` })).statusCode).toBe(401);
+  }
+  expect((await login(app, { password: `${password}!` })).statusCode).toBe(429);
+});
+
 test("public auth configuration is safe and OIDC protocol placeholders fail closed", async () => {
   const { app } = await createLocalApp();
   const configuration = await app.inject({ method: "GET", url: "/auth/config" });

backend/test/auth.test.ts

@@ -5,6 +5,8 @@ import { chmodSync, mkdtempSync, readFileSync, rmSync, statSync } from "node:fs"
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { expandLocalHome, localPrincipal, upstreamPrincipal } from "../src/auth/principal.js";
+import { buildApp } from "../src/app.js";
+import { loadConfig } from "../src/config.js";
 
 test("server smoke trusted claims transform through nginx to a non-admin principal", () => {
   const smoke = readFileSync("../scripts/unified-deployment-smoke.sh", "utf8");
@@ -107,6 +109,48 @@ test("upstream mode rejects legacy client identity headers without proxy princip
   }
 });
 
+test("buildApp exposes safe nullable session metadata for authenticated legacy modes", async () => {
+  const configurations = [
+    {
+      name: "none",
+      config: loadConfig({ NODE_ENV: "test", AUTH_MODE: "none", THT_HARNESS_DIR: "/tmp/h" }),
+      headers: {},
+      expected: { issuer: "local", roles: ["admin"] },
+    },
+    {
+      name: "mock",
+      config: loadConfig({ NODE_ENV: "test", AUTH_MODE: "mock", THT_HARNESS_DIR: "/tmp/h" }),
+      headers: { "x-mock-user": "legacy-mock" },
+      expected: { issuer: "mock", subject: "legacy-mock", roles: ["user"] },
+    },
+    {
+      name: "upstream",
+      config: loadConfig({ NODE_ENV: "production", AUTH_MODE: "upstream", THT_HARNESS_DIR: "/tmp/h" }),
+      headers: {
+        "x-thoth-principal-issuer": "portal",
+        "x-thoth-principal-subject": "legacy-upstream",
+        "x-thoth-is-admin": "0",
+      },
+      expected: { issuer: "portal", subject: "legacy-upstream", roles: ["user"] },
+    },
+  ];
+
+  for (const legacy of configurations) {
+    const app = buildApp(legacy.config, { thtRunner: {} as any, listModels: async () => [] });
+    try {
+      const response = await app.inject({ method: "GET", url: "/me", headers: legacy.headers });
+      expect(response.statusCode, legacy.name).toBe(200);
+      expect(response.json()).toMatchObject({
+        ...legacy.expected,
+        csrfToken: null,
+        session: null,
+      });
+    } finally {
+      await app.close();
+    }
+  }
+});
+
 test("the session boundary exposes only exact health and authentication protocol paths", async () => {
   const app = Fastify();
   app.addHook("preHandler", authenticateSession({

tools/tht/internal/authconfig/password.go

@@ -20,13 +20,6 @@ const (
 	argon2SaltBytes        = 16
 	argon2KeyBytes  uint32 = 32
 
-	argon2MaximumMemoryKiB uint32 = 256 * 1024
-	argon2MaximumPasses    uint32 = 10
-	argon2MaximumParallel  uint8  = 4
-	argon2MinimumSaltBytes        = 16
-	argon2MaximumSaltBytes        = 64
-	argon2MinimumKeyBytes  uint32 = 16
-	argon2MaximumKeyBytes  uint32 = 64
 	maximumPHCBytes               = 256
 )
 
@@ -55,7 +48,7 @@ func HashPassword(password []byte, random io.Reader) (string, error) {
 	return "$argon2id$v=19$m=65536,t=3,p=1$" + base64.RawStdEncoding.EncodeToString(salt) + "$" + base64.RawStdEncoding.EncodeToString(digest), nil
 }
 
-// VerifyPassword accepts only bounded, canonical Argon2id v19 PHC strings.
+// VerifyPassword accepts only the exact canonical Argon2id v19 policy.
 func VerifyPassword(password []byte, encoded string) bool {
 	if !validPassword(password) {
 		return false
@@ -84,11 +77,11 @@ func parsePHC(encoded string) (argon2Parameters, bool) {
 	if !ok {
 		return argon2Parameters{}, false
 	}
-	salt, ok := decodePHCBase64(parts[4], argon2MinimumSaltBytes, argon2MaximumSaltBytes)
+	salt, ok := decodePHCBase64(parts[4], argon2SaltBytes, argon2SaltBytes)
 	if !ok {
 		return argon2Parameters{}, false
 	}
-	digest, ok := decodePHCBase64(parts[5], int(argon2MinimumKeyBytes), int(argon2MaximumKeyBytes))
+	digest, ok := decodePHCBase64(parts[5], int(argon2KeyBytes), int(argon2KeyBytes))
 	if !ok {
 		return argon2Parameters{}, false
 	}
@@ -102,16 +95,16 @@ func parsePHCParameters(value string) (argon2Parameters, bool) {
 	if len(parts) != 3 || !strings.HasPrefix(parts[0], "m=") || !strings.HasPrefix(parts[1], "t=") || !strings.HasPrefix(parts[2], "p=") {
 		return argon2Parameters{}, false
 	}
-	memory, ok := parseDecimal(parts[0][2:], uint64(argon2MaximumMemoryKiB))
-	if !ok || memory < 8 {
+	memory, ok := parseDecimal(parts[0][2:], uint64(argon2MemoryKiB))
+	if !ok || memory != uint64(argon2MemoryKiB) {
 		return argon2Parameters{}, false
 	}
-	passes, ok := parseDecimal(parts[1][2:], uint64(argon2MaximumPasses))
-	if !ok || passes == 0 {
+	passes, ok := parseDecimal(parts[1][2:], uint64(argon2Passes))
+	if !ok || passes != uint64(argon2Passes) {
 		return argon2Parameters{}, false
 	}
-	parallelism, ok := parseDecimal(parts[2][2:], uint64(argon2MaximumParallel))
-	if !ok || parallelism == 0 || memory < 8*parallelism {
+	parallelism, ok := parseDecimal(parts[2][2:], uint64(argon2Parallel))
+	if !ok || parallelism != uint64(argon2Parallel) {
 		return argon2Parameters{}, false
 	}
 	return argon2Parameters{memory: uint32(memory), passes: uint32(passes), parallelism: uint8(parallelism)}, true

tools/tht/internal/authconfig/password_test.go

@@ -57,6 +57,7 @@ func TestVerifyPasswordRejectsMalformedAndOversizedPHCBeforeHashing(t *testing.T
 		"memory too large":      "$argon2id$v=19$m=262145,t=1,p=1$AAECAwQFBgcICQoLDA0ODw$DRo8ZSPI8G5OCvnFFapbVEjP69aDjy1Sw9i2743cPC4",
 		"passes too large":      "$argon2id$v=19$m=65536,t=11,p=1$AAECAwQFBgcICQoLDA0ODw$DRo8ZSPI8G5OCvnFFapbVEjP69aDjy1Sw9i2743cPC4",
 		"parallelism too large": "$argon2id$v=19$m=65536,t=3,p=5$AAECAwQFBgcICQoLDA0ODw$DRo8ZSPI8G5OCvnFFapbVEjP69aDjy1Sw9i2743cPC4",
+		"weak bounded policy":  "$argon2id$v=19$m=8,t=1,p=1$AAECAwQFBgcICQoLDA0ODw$DRo8ZSPI8G5OCvnFFapbVEjP69aDjy1Sw9i2743cPC4",
 		"short salt":            "$argon2id$v=19$m=65536,t=3,p=1$AAECAwQFBgcICQoLDA0O$DRo8ZSPI8G5OCvnFFapbVEjP69aDjy1Sw9i2743cPC4",
 		"long digest":           "$argon2id$v=19$m=65536,t=3,p=1$AAECAwQFBgcICQoLDA0ODw$AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
 	} {