feat(auth): add login audience middleware (EDRFREIGHT-415)

apps/edr-freight-api/src/modules/auth/login-audience.middleware.ts

@@ -0,0 +1,58 @@
+import { ForbiddenException, Injectable, NestMiddleware } from '@nestjs/common';
+import { InjectDataSource } from '@nestjs/typeorm';
+import { DataSource } from 'typeorm';
+import { NextFunction, Request, Response } from 'express';
+
+export const CLIENT_APP_HEADER = 'x-client-app';
+
+// EUserType values from @tria-plc/api-common, duplicated here to avoid
+// pulling in the full enum just for this string comparison.
+const ALLOWED_USER_TYPES_BY_CLIENT: Record<string, string[]> = {
+  backoffice: ['employee'],
+  portal: ['individual', 'external_organization'],
+};
+
+/**
+ * Blocks EDRFREIGHT-415: /auth/login and /auth/mfa-verify match credentials
+ * against email/username/phone_number only (see vendor
+ * findUserForLogin), with no check that the account's userType belongs on
+ * the app that's asking. A backoffice (employee) client presenting a
+ * customer's credentials — or vice versa — must not get a session.
+ */
+@Injectable()
+export class LoginAudienceMiddleware implements NestMiddleware {
+  constructor(@InjectDataSource() private readonly dataSource: DataSource) {}
+
+  async use(req: Request, _res: Response, next: NextFunction) {
+    const clientApp = req.header(CLIENT_APP_HEADER);
+    const allowedUserTypes = clientApp
+      ? ALLOWED_USER_TYPES_BY_CLIENT[clientApp]
+      : undefined;
+    if (!allowedUserTypes) {
+      throw new ForbiddenException(
+        `Missing or unrecognized ${CLIENT_APP_HEADER} header`,
+      );
+    }
+
+    const identifier: unknown = req.body?.email;
+    if (typeof identifier !== 'string' || !identifier) {
+      // No identifier to look up — the vendor DTO validation rejects the
+      // request on its own.
+      return next();
+    }
+
+    const [user] = await this.dataSource.query(
+      `SELECT user_type AS "userType" FROM iam.users
+       WHERE email = $1 OR username = $1 OR phone_number = $1 LIMIT 1`,
+      [identifier],
+    );
+
+    if (user && !allowedUserTypes.includes(user.userType)) {
+      throw new ForbiddenException(
+        `This account cannot sign in through the ${clientApp} application`,
+      );
+    }
+
+    next();
+  }
+}