refactor: implement ALLOWED_ROOT_DIRECTORY security and fix path validation

This commit consolidates directory security from two environment variables
(WORKSPACE_DIR, ALLOWED_PROJECT_DIRS) into a single ALLOWED_ROOT_DIRECTORY variable
while maintaining backward compatibility.

Changes:
- Re-enabled path validation in security.ts (was previously disabled)
- Implemented isPathAllowed() to check ALLOWED_ROOT_DIRECTORY with DATA_DIR exception
- Added backward compatibility for legacy ALLOWED_PROJECT_DIRS and WORKSPACE_DIR
- Implemented path traversal protection via isPathWithinDirectory() helper
- Added PathNotAllowedError custom exception for security violations
- Updated all FS route endpoints to validate paths and return 403 on violation
- Updated template clone endpoint to validate project paths
- Updated workspace config endpoints to use ALLOWED_ROOT_DIRECTORY
- Fixed stat() response property access bug in project-init.ts
- Updated security tests to expect actual validation behavior

Security improvements:
- Path validation now enforced at all layers (routes, project init, agent services)
- appData directory (DATA_DIR) always allowed for settings/credentials
- Backward compatible with existing ALLOWED_PROJECT_DIRS/WORKSPACE_DIR configurations
- Protection against path traversal attacks

Backend test results: 654/654 passing ✅

🤖 Generated with Claude Code

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

apps/server/src/routes/workspace/routes/config.ts

@@ -4,13 +4,16 @@
 
 import type { Request, Response } from "express";
 import fs from "fs/promises";
-import { addAllowedPath } from "../../../lib/security.js";
+import path from "path";
+import { addAllowedPath, getAllowedRootDirectory } from "../../../lib/security.js";
 import { getErrorMessage, logError } from "../common.js";
 
 export function createConfigHandler() {
   return async (_req: Request, res: Response): Promise<void> => {
     try {
-      const workspaceDir = process.env.WORKSPACE_DIR;
+      // Prefer ALLOWED_ROOT_DIRECTORY, fall back to WORKSPACE_DIR for backward compatibility
+      const allowedRootDirectory = getAllowedRootDirectory();
+      const workspaceDir = process.env.WORKSPACE_DIR || allowedRootDirectory;
 
       if (!workspaceDir) {
         res.json({
@@ -22,29 +25,30 @@ export function createConfigHandler() {
 
       // Check if the directory exists
       try {
-        const stats = await fs.stat(workspaceDir);
+        const resolvedWorkspaceDir = path.resolve(workspaceDir);
+        const stats = await fs.stat(resolvedWorkspaceDir);
         if (!stats.isDirectory()) {
           res.json({
             success: true,
             configured: false,
-            error: "WORKSPACE_DIR is not a valid directory",
+            error: "Configured workspace directory is not a valid directory",
           });
           return;
         }
 
         // Add workspace dir to allowed paths
-        addAllowedPath(workspaceDir);
+        addAllowedPath(resolvedWorkspaceDir);
 
         res.json({
           success: true,
           configured: true,
-          workspaceDir,
+          workspaceDir: resolvedWorkspaceDir,
         });
       } catch {
         res.json({
           success: true,
           configured: false,
-          error: "WORKSPACE_DIR path does not exist",
+          error: "Configured workspace directory path does not exist",
         });
       }
     } catch (error) {

apps/server/src/routes/workspace/routes/directories.ts

@@ -5,45 +5,49 @@
 import type { Request, Response } from "express";
 import fs from "fs/promises";
 import path from "path";
-import { addAllowedPath } from "../../../lib/security.js";
+import { addAllowedPath, getAllowedRootDirectory } from "../../../lib/security.js";
 import { getErrorMessage, logError } from "../common.js";
 
 export function createDirectoriesHandler() {
   return async (_req: Request, res: Response): Promise<void> => {
     try {
-      const workspaceDir = process.env.WORKSPACE_DIR;
+      // Prefer ALLOWED_ROOT_DIRECTORY, fall back to WORKSPACE_DIR for backward compatibility
+      const allowedRootDirectory = getAllowedRootDirectory();
+      const workspaceDir = process.env.WORKSPACE_DIR || allowedRootDirectory;
 
       if (!workspaceDir) {
         res.status(400).json({
           success: false,
-          error: "WORKSPACE_DIR is not configured",
+          error: "Workspace directory is not configured (set ALLOWED_ROOT_DIRECTORY or WORKSPACE_DIR)",
         });
         return;
       }
 
+      const resolvedWorkspaceDir = path.resolve(workspaceDir);
+
       // Check if directory exists
       try {
-        await fs.stat(workspaceDir);
+        await fs.stat(resolvedWorkspaceDir);
       } catch {
         res.status(400).json({
           success: false,
-          error: "WORKSPACE_DIR path does not exist",
+          error: "Workspace directory path does not exist",
         });
         return;
       }
 
       // Add workspace dir to allowed paths
-      addAllowedPath(workspaceDir);
+      addAllowedPath(resolvedWorkspaceDir);
 
       // Read directory contents
-      const entries = await fs.readdir(workspaceDir, { withFileTypes: true });
+      const entries = await fs.readdir(resolvedWorkspaceDir, { withFileTypes: true });
 
       // Filter to directories only and map to result format
       const directories = entries
         .filter((entry) => entry.isDirectory() && !entry.name.startsWith("."))
         .map((entry) => ({
           name: entry.name,
-          path: path.join(workspaceDir, entry.name),
+          path: path.join(resolvedWorkspaceDir, entry.name),
         }))
         .sort((a, b) => a.name.localeCompare(b.name));