Fix security concerns - restrictive file permissions and remove secret logging

Co-authored-by: Stalin-143 <161853795+Stalin-143@users.noreply.github.com>

backend/main.py

@@ -123,6 +123,7 @@ def get_dev_fallback_secret(name: str) -> str:
     Stores the secret in a file to persist across restarts.
     """
     import tempfile
+    import stat
     secret_file = os.path.join(tempfile.gettempdir(), f'.openlearnx_dev_{name}')
     try:
         if os.path.exists(secret_file):
@@ -135,6 +136,8 @@ def get_dev_fallback_secret(name: str) -> str:
     try:
         with open(secret_file, 'w') as f:
             f.write(new_secret)
+        # Set restrictive permissions (owner read/write only)
+        os.chmod(secret_file, stat.S_IRUSR | stat.S_IWUSR)
     except Exception:
         pass  # If we can't persist, just return the generated secret
     return new_secret
@@ -150,7 +153,6 @@ except ValueError as e:
     _secret_key = os.getenv('SECRET_KEY') or get_dev_fallback_secret('secret_key')
     _jwt_secret_key = os.getenv('JWT_SECRET_KEY') or get_dev_fallback_secret('jwt_secret_key')
     _admin_token = os.getenv('ADMIN_TOKEN') or get_dev_fallback_secret('admin_token')
-    print(f"⚠️ DEV ADMIN_TOKEN (first 8 chars): {_admin_token[:8]}...")
 
 app.config.update(
     SECRET_KEY=_secret_key,

backend/routes/admin.py

@@ -29,7 +29,6 @@ def admin_required(f):
                 return jsonify({"error": "Invalid authorization format"}), 401
             
             token = auth_header.split(' ')[1] if len(auth_header.split(' ')) > 1 else None
-            print(f"Extracted token: '{token}'")
             
             # Check environment variable - no fallback for security
             expected_token = os.getenv('ADMIN_TOKEN')
@@ -37,9 +36,6 @@ def admin_required(f):
                 print("❌ ADMIN_TOKEN environment variable not set")
                 return jsonify({"error": "Server configuration error: ADMIN_TOKEN not configured"}), 500
             
-            print(f"Expected token: '{expected_token}'")
-            print(f"Environment ADMIN_TOKEN: '{os.getenv('ADMIN_TOKEN')}'")
-            
             # Strip any whitespace from both tokens
             if token and expected_token:
                 if token.strip() == expected_token.strip():

backend/routes/auth.py

@@ -21,6 +21,7 @@ JWT_SECRET = os.getenv('JWT_SECRET')
 if not JWT_SECRET:
     import warnings
     import tempfile
+    import stat
     warnings.warn("JWT_SECRET environment variable not set. Using persistent dev secret.", UserWarning)
     # Use persistent file-based secret for development to avoid invalidating tokens on restart
     _secret_file = os.path.join(tempfile.gettempdir(), '.openlearnx_dev_jwt_secret_auth')
@@ -33,6 +34,8 @@ if not JWT_SECRET:
             JWT_SECRET = _secrets.token_hex(32)
             with open(_secret_file, 'w') as f:
                 f.write(JWT_SECRET)
+            # Set restrictive permissions (owner read/write only)
+            os.chmod(_secret_file, stat.S_IRUSR | stat.S_IWUSR)
     except Exception:
         import secrets as _secrets
         JWT_SECRET = _secrets.token_hex(32)