feat: login policy hook for plugins and optional https redirect (#1584)

src/backend/auth/login-pipeline.ts

@@ -26,6 +26,12 @@ import {
   isSecondFactorAfterExternalLoginEnabled,
 } from "./core-auth.js";
 import { findOrProvisionExternalUser } from "./provisioning.js";
+import {
+  SECOND_FACTOR_SETUP,
+  evaluateAuthPolicy,
+  hasAuthPolicies,
+  rememberDeviceAllowed,
+} from "./policy.js";
 import {
   getLoginMethod,
   getSecondFactor,
@@ -122,12 +128,15 @@ export async function evaluateSecondFactors(
  * governs external methods (SSO, LDAP) alone.
  */
 function shouldRunSecondFactors(methodId: string): boolean {
-  ensureCoreLoginProviders();
-  const method = getLoginMethod(methodId);
-  if (!method?.external) return true;
+  if (!isExternalMethod(methodId)) return true;
   return isSecondFactorAfterExternalLoginEnabled();
 }
 
+function isExternalMethod(methodId: string): boolean {
+  ensureCoreLoginProviders();
+  return !!getLoginMethod(methodId)?.external;
+}
+
 export const TRUST_DEVICE_COOKIE = "termix_trust_device";
 const TRUST_TOKEN_PATTERN = /^[a-f0-9]{64}$/;
 const TRUST_TOKEN_MAX_AGE_MS = 30 * 24 * 60 * 60 * 1000;
@@ -294,9 +303,40 @@ export async function runLogin(
     `${context.methodId}_role_shared_credentials`,
   );
 
-  const factors = shouldRunSecondFactors(context.methodId)
-    ? await evaluateSecondFactors(user.id)
-    : { required: [], blocked: [] };
+  // A login policy may want a factor where core would skip it, so it always
+  // sees the full picture.
+  const runFactors = shouldRunSecondFactors(context.methodId);
+  const factors =
+    runFactors || hasAuthPolicies()
+      ? await evaluateSecondFactors(user.id)
+      : { required: [], blocked: [] };
+  const trusted =
+    factors.required.length > 0 || hasAuthPolicies()
+      ? await isTrustedDevice(req, user.id)
+      : false;
+  const policy = await evaluateAuthPolicy({
+    userId: user.id,
+    methodId: context.methodId,
+    external: isExternalMethod(context.methodId),
+    deviceType,
+    trustedDevice: trusted,
+    mfaSatisfied: !!identity.mfaSatisfied,
+    secondFactors: listSecondFactors().map((factor) => ({
+      id: factor.id,
+      pluginId: factor.pluginId,
+      enrolled: factors.required.some(
+        (required) =>
+          required.id === factor.id && required.pluginId === factor.pluginId,
+      ),
+    })),
+  });
+  if (!runFactors && !policy.secondFactor) {
+    factors.required = [];
+    factors.blocked = [];
+  }
+  const rememberMe = context.rememberMe && policy.allowRememberDevice;
+  const skipByDevice =
+    trusted && policy.allowRememberDevice && policy.secondFactor !== "always";
   if (factors.blocked.length > 0) {
     authLogger.warn("Login refused: an enrolled second factor is unavailable", {
       operation: "second_factor_unavailable",
@@ -324,11 +364,7 @@ export async function runLogin(
 
   const ssoClaims = { externalSession: identity.externalSession ?? null };
 
-  if (
-    factors.required.length > 0 &&
-    !identity.mfaSatisfied &&
-    !(await isTrustedDevice(req, user.id))
-  ) {
+  if (factors.required.length > 0 && !identity.mfaSatisfied && !skipByDevice) {
     const tempToken = await AuthManager.getInstance().generateJWTToken(
       user.id,
       { pendingTOTP: true, expiresIn: "10m" },
@@ -337,14 +373,17 @@ export async function runLogin(
     pendingLogins.set(pendingKey(tempToken), {
       userId: user.id,
       methodId: context.methodId,
-      rememberMe: context.rememberMe,
+      rememberMe,
+      allowRememberDevice: policy.allowRememberDevice,
+      maxSessionSeconds: policy.maxSessionSeconds,
+      idleTimeoutSeconds: policy.idleTimeoutSeconds,
       ...ssoClaims,
       createdAt: Date.now(),
     });
     return {
       kind: "second-factor",
       tempToken,
-      rememberMe: context.rememberMe,
+      rememberMe,
       factors: factors.required.map((factor) => ({
         id: factor.id,
         pluginId: factor.pluginId,
@@ -353,11 +392,22 @@ export async function runLogin(
     };
   }
 
+  // Required but nothing set up yet: a session that can only set one up.
+  const needsSetup =
+    !!policy.secondFactor &&
+    factors.required.length === 0 &&
+    !identity.mfaSatisfied &&
+    !skipByDevice;
+
   const session = await issueSession(req, user, {
     methodId: context.methodId,
-    rememberMe: context.rememberMe,
+    rememberMe,
     rateLimitUsername: context.rateLimitUsername ?? identity.rateLimitUsername,
-    longLivedForApps: identity.kind === "external",
+    longLivedForApps:
+      identity.kind === "external" && policy.allowRememberDevice,
+    maxAgeSeconds: policy.maxSessionSeconds,
+    idleTimeoutSeconds: policy.idleTimeoutSeconds,
+    restriction: needsSetup ? SECOND_FACTOR_SETUP : null,
     ...ssoClaims,
   });
   return { kind: "session", ...session };
@@ -510,10 +560,15 @@ export async function verifySecondFactorAndRespond(
   }
   loginRateLimiter.resetTOTPAttempts(user.id);
 
+  // A pending entry lost to a restart falls back to the current policy.
+  const allowRemember = lookup.pending
+    ? lookup.pending.allowRememberDevice !== false
+    : rememberDeviceAllowed();
   const rememberMe =
-    typeof req.body?.rememberMe === "boolean"
+    allowRemember &&
+    (typeof req.body?.rememberMe === "boolean"
       ? req.body.rememberMe
-      : (lookup.pending?.rememberMe ?? false);
+      : (lookup.pending?.rememberMe ?? false));
 
   let trustToken: string | null = null;
   if (rememberMe) {
@@ -545,6 +600,8 @@ export async function verifySecondFactorAndRespond(
     methodId: pending?.methodId ?? "password",
     rememberMe,
     externalSession: pending?.externalSession ?? null,
+    maxAgeSeconds: pending?.maxSessionSeconds ?? null,
+    idleTimeoutSeconds: pending?.idleTimeoutSeconds ?? null,
   });
 
   if (trustToken && isNativeAppRequest(req)) {

src/backend/auth/policy.ts

@@ -0,0 +1,125 @@
+/**
+ * Login policy from plugins through ctx.auth.policy.provide: idle timeout,
+ * session length, remember me and a required second factor. Core asks every
+ * provider and the strictest answer wins. A provider that throws at login
+ * refuses the login, since skipping a security rule is worse than a failed
+ * sign in. The idle timeout is stored on the session at login. Desktop
+ * loopback, sync link and plugin minted sessions are device credentials, not
+ * logins, so the policy never reaches them.
+ */
+
+import type {
+  PluginAuthPolicyDecision,
+  PluginAuthPolicyInput,
+  PluginAuthPolicyProvider,
+} from "@termix-ssh/plugin-sdk/backend";
+import { authLogger } from "../utils/logger.js";
+import { LoginMethodError } from "./types.js";
+
+/** sessions.restriction of a session that may only set up a second factor. */
+export const SECOND_FACTOR_SETUP = "second-factor-setup";
+
+interface Entry {
+  pluginId: string;
+  provider: PluginAuthPolicyProvider;
+}
+
+const providers = new Map<symbol, Entry>();
+
+export function provideAuthPolicy(
+  pluginId: string,
+  provider: PluginAuthPolicyProvider,
+): () => void {
+  const key = Symbol(pluginId);
+  providers.set(key, { pluginId, provider });
+  return () => {
+    providers.delete(key);
+  };
+}
+
+/** Test seam. */
+export function clearAuthPolicies(): void {
+  providers.clear();
+}
+
+export function hasAuthPolicies(): boolean {
+  return providers.size > 0;
+}
+
+export interface AuthPolicy {
+  allowRememberDevice: boolean;
+  maxSessionSeconds: number | null;
+  idleTimeoutSeconds: number | null;
+  secondFactor: "always" | "new-device" | null;
+}
+
+const NO_POLICY: AuthPolicy = {
+  allowRememberDevice: true,
+  maxSessionSeconds: null,
+  idleTimeoutSeconds: null,
+  secondFactor: null,
+};
+
+function shortest(current: number | null, next: unknown): number | null {
+  if (typeof next !== "number" || !(next > 0)) return current;
+  const value = Math.floor(next);
+  return current === null ? value : Math.min(current, value);
+}
+
+function merge(policy: AuthPolicy, next: PluginAuthPolicyDecision): AuthPolicy {
+  let secondFactor = policy.secondFactor;
+  if (next.secondFactor === "always") secondFactor = "always";
+  else if (next.secondFactor === "new-device" && secondFactor !== "always") {
+    secondFactor = "new-device";
+  }
+  return {
+    allowRememberDevice:
+      policy.allowRememberDevice && next.allowRememberDevice !== false,
+    maxSessionSeconds: shortest(
+      policy.maxSessionSeconds,
+      next.maxSessionSeconds,
+    ),
+    idleTimeoutSeconds: shortest(
+      policy.idleTimeoutSeconds,
+      next.idleTimeoutSeconds,
+    ),
+    secondFactor,
+  };
+}
+
+export async function evaluateAuthPolicy(
+  input: PluginAuthPolicyInput,
+): Promise<AuthPolicy> {
+  let policy = NO_POLICY;
+  for (const entry of providers.values()) {
+    let decision: PluginAuthPolicyDecision;
+    try {
+      decision = (await entry.provider.evaluate(input)) ?? {};
+    } catch (error) {
+      authLogger.warn("Login policy failed, refusing the login", {
+        operation: "auth_policy",
+        pluginId: entry.pluginId,
+        error: error instanceof Error ? error.message : String(error),
+      });
+      throw new LoginMethodError(
+        "Sign in is not available right now. Contact an admin.",
+        503,
+        "auth_policy_unavailable",
+      );
+    }
+    policy = merge(policy, decision);
+  }
+  return policy;
+}
+
+/** Whether the login page should offer remember me. */
+export function rememberDeviceAllowed(): boolean {
+  for (const entry of providers.values()) {
+    try {
+      if (entry.provider.allowRememberDevice?.() === false) return false;
+    } catch {
+      return false;
+    }
+  }
+  return true;
+}

src/backend/auth/session-issuer.ts

@@ -68,6 +68,11 @@ export interface IssueSessionOptions {
   externalSession?: ExternalSessionRef | null;
   /** SSO logins keep desktop and mobile apps signed in for 30 days. */
   longLivedForApps?: boolean;
+  /** Login policy cap on the session length. */
+  maxAgeSeconds?: number | null;
+  /** See SECOND_FACTOR_SETUP. */
+  restriction?: string | null;
+  idleTimeoutSeconds?: number | null;
 }
 
 export interface IssuedSession {
@@ -93,6 +98,9 @@ export async function issueSession(
     deviceType: deviceInfo.type,
     deviceInfo: deviceInfo.deviceInfo,
     externalSession: options.externalSession ?? null,
+    maxAgeSeconds: options.maxAgeSeconds ?? null,
+    restriction: options.restriction ?? null,
+    idleTimeoutSeconds: options.idleTimeoutSeconds ?? null,
   });
 
   if (options.rateLimitUsername) {
@@ -123,11 +131,14 @@ export async function issueSession(
     method: options.methodId,
   });
 
-  const maxAge =
+  let maxAge =
     options.longLivedForApps &&
     (deviceInfo.type === "desktop" || deviceInfo.type === "mobile")
       ? THIRTY_DAYS_MS
       : await sessionCookieMaxAge(options.rememberMe);
+  if (options.maxAgeSeconds) {
+    maxAge = Math.min(maxAge, options.maxAgeSeconds * 1000);
+  }
 
   return {
     token,
@@ -142,6 +153,7 @@ export async function issueSession(
       totp_enabled: await createCurrentUserAuthRepository().hasSecondFactor(
         user.id,
       ),
+      ...(options.restriction ? { restriction: options.restriction } : {}),
       ...(isNativeAppRequest(req) ? { token } : {}),
     },
   };

src/backend/auth/types.ts

@@ -35,5 +35,9 @@ export interface PendingLogin {
   methodId: string;
   rememberMe: boolean;
   externalSession?: ExternalSessionRef | null;
+  /** Login policy that applied when the login paused. */
+  allowRememberDevice?: boolean;
+  maxSessionSeconds?: number | null;
+  idleTimeoutSeconds?: number | null;
   createdAt: number;
 }