CSRF django nginx with ssl from cloudflare

Question

Background

I'm trying to configure my Django app to work with ssl provided by cloudflare. I have about the same setup as this answer and have followed the same solution.

Issue:

This has been killing me for weeks (please help!) as I am not a networking/security guy and just need a solution that will avoid me gouging my eyes out but keep the site secure.

I am currently getting a CSRF issue where https://www.domain.co.uk does not match https://domain.co.uk

Config

Settings.py

SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTOCOL', 'https')
MIDDLEWARE_CLASSES = (
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
)
USE_X_FORWARDED_HOST = True

nginx:

server {

    listen 80 default_server;

    server_name domain.co.uk www.domain.co.uk;
    access_log off;

    location /static/ {
        alias /static/;
    }


    location / {
            proxy_pass http://127.0.0.1:8000;
            proxy_set_header X-Forwarded-Host $server_name;
            proxy_set_header X-Real-IP $remote_addr;
            add_header P3P 'CP="ALL DSP COR PSAa PSDa OUR NOR ONL UNI COM NAV"';

            proxy_set_header X-Scheme $scheme;
            proxy_set_header X-Forwarded-Protocol $scheme;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $http_host;
            }
}

Cloudflare DNS:

A domain.co.uk  points to <ip> Automatic
CNAME www is an alias of domain.co.uk Automatic 

Bonus

In addition I also have the .com for the domain and would like to know how best to set this up so that it is also ssl.

Answer 1

You need to setup the domain which is sending the CSRF cookie. Try setting CSRF_COOKIE_DOMAIN to ".domain.co.uk" and CSRF_COOKIE_SECURE to True in your settings.

Relevant documentation https://docs.djangoproject.com/en/4.1/ref/csrf/#how-it-works