Rate limit failed web logins to 5 in 5 minutes

rootfs/standard/var/www/mynode/mynode.py

@@ -696,7 +696,7 @@ def page_login():
     if login(pw):
         return redirect("/")
     else:
-        flash("Invalid Password", category="error")
+        flash(get_login_error_message(), category="error")
         return redirect("/login")
 
 @app.route("/logout")

rootfs/standard/var/www/mynode/user_management.py

@@ -1,9 +1,15 @@
 from flask import Blueprint, render_template, session, abort, Markup, request, redirect, send_from_directory, url_for, flash
 from config import *
+import time
 import pam
 import os
 import subprocess
 
+# Globals
+recent_invalid_login_attempt = 0
+recent_invalid_login_time_marker = 0
+login_error_message = ""
+
 # Exceptions
 class LoginError(Exception):
    """Raised when a user is not logged in"""
@@ -22,8 +28,16 @@ def is_logged_in():
     return False
 
 def login(password):
+    global login_error_message
+
+    if get_recent_invalid_login_attempts() >= 5:
+        login_error_message = "Too Many Invalid Attempts - Wait 5 minutes"
+        return False
+
     p = pam.pam()
     if password == None or p.authenticate("admin", password) == False:
+        login_error_message = "Invalid Password"
+        increase_recent_invalid_login_attempts()
         return False
     else:
         session["logged_in"] = True
@@ -35,3 +49,27 @@ def logout():
 
 def handle_login_exception(e):
     return redirect("/login")
+
+def get_recent_invalid_login_attempts():
+    global recent_invalid_login_attempts
+    global recent_invalid_login_time_marker
+
+    # Reset count if it's been 5 minutes since first bad login
+    if time.time() > recent_invalid_login_time_marker + 300:
+        recent_invalid_login_attempts = 0
+
+    return recent_invalid_login_attempts
+
+def increase_recent_invalid_login_attempts():
+    global recent_invalid_login_attempts
+    global recent_invalid_login_time_marker
+
+    # Mark time of first invalid login so we know when we would need to reset
+    if recent_invalid_login_attempts == 0:
+        recent_invalid_login_time_marker = time.time()
+
+    recent_invalid_login_attempts += 1
+
+def get_login_error_message():
+    global login_error_message
+    return login_error_message