dotfiles/nixos/boxes/vpsfree1/cryptpad.nginx.config

#   This file is included strictly as an example of how Nginx can be configured
#   to work with CryptPad. This example WILL NOT WORK AS IS. For best results,
#   compare the sections of this configuration file against a working CryptPad
#   installation (http server by the Nodejs process). If you are using CryptPad
#   in production and require professional support please contact sales@cryptpad.fr

server {
    listen 443 ssl http2;

# CryptPad serves static assets over these two domains.
# `main_domain` is what users will enter in their address bar.
# Privileged computation such as key management is handled in this scope
# UI content is loaded via the `sandbox_domain`.
# "Content Security Policy" headers prevent content loaded via the sandbox
# from accessing privileged information.
# These variables must be different to take advantage of CryptPad's sandboxing techniques.
# In the event of an XSS vulnerability in CryptPad's front-end code
# this will limit the amount of information accessible to attackers.
    set $main_domain "notes.purrfect.estate";
    set $sandbox_domain "notes-sandbox.purrfect.estate";

# By default CryptPad allows remote domains to embed CryptPad documents in iframes.
# This behaviour can be blocked by changing $allowed_origins from "*" to the
# sandbox domain, which must be permitted to load content from the main domain
# in order for CryptPad to work as expected.
#
# An example is given below which can be uncommented if you want to block
# remote sites from including content from your server
    set $allowed_origins "*";
    set $allowed_origins "https://${sandbox_domain}";

# CryptPad's dynamic content (websocket traffic and encrypted blobs)
# can be served over separate domains. Using dedicated domains (or subdomains)
# for these purposes allows you to move them to a separate machine at a later date
# if you find that a single machine cannot handle all of your users.
# If you don't use dedicated domains, this can be the same as $main_domain
# If you do, they can be added as exceptions to any rules which block connections to remote domains.
# You can find these variables referenced below in the relevant places
    set $api_domain "notes.purrfect.estate";
    set $files_domain "notes.purrfect.estate";

    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    add_header X-XSS-Protection "1; mode=block";
    add_header X-Content-Type-Options nosniff;
    add_header Access-Control-Allow-Origin "${allowed_origins}";
# add_header X-Frame-Options "SAMEORIGIN";

# Opt out of Google's FLoC Network
    add_header Permissions-Policy interest-cohort=();

# Enable SharedArrayBuffer in Firefox (for .xlsx export)
    add_header Cross-Origin-Resource-Policy cross-origin;
    add_header Cross-Origin-Embedder-Policy require-corp;

# any static assets loaded with "ver=" in their URL will be cached for a year
    if ($args ~ ver=) {
        set $cacheControl max-age=31536000;
    }
    if ($uri ~ ^/.*(\/|\.html)$) {
        set $cacheControl no-cache;
    }
# Will not set any header if it is emptystring
    add_header Cache-Control $cacheControl;

# CSS can be dynamically set inline, loaded from the same domain, or from $main_domain
    set $styleSrc   "'unsafe-inline' 'self' https://${main_domain}";

# connect-src restricts URLs which can be loaded using script interfaces
# if you have configured your instance to use a dedicated $files_domain or $api_domain
# you will need to add them below as: https://${files_domain} and https://${api_domain}
    set $connectSrc "'self' https://${main_domain} blob: wss://${api_domain} https://${sandbox_domain}";

# fonts can be loaded from data-URLs or the main domain
    set $fontSrc    "'self' data: https://${main_domain}";

# images can be loaded from anywhere, though we'd like to deprecate this as it allows the use of images for tracking
    set $imgSrc     "'self' data: blob: https://${main_domain}";

# frame-src specifies valid sources for nested browsing contexts.
# this prevents loading any iframes from anywhere other than the sandbox domain
    set $frameSrc   "'self' https://${sandbox_domain} blob:";

# specifies valid sources for loading media using video or audio
    set $mediaSrc   "blob:";

# defines valid sources for webworkers and nested browser contexts
# deprecated in favour of worker-src and frame-src
    set $childSrc   "https://${main_domain}";

# specifies valid sources for Worker, SharedWorker, or ServiceWorker scripts.
# supercedes child-src but is unfortunately not yet universally supported.
    set $workerSrc  "'self'";

# script-src specifies valid sources for javascript, including inline handlers
    set $scriptSrc  "'self' resource: https://${main_domain}";

# frame-ancestors specifies which origins can embed your CryptPad instance
# this must include 'self' and your main domain (over HTTPS) in order for CryptPad to work
# if you have enabled remote embedding via the admin panel then this must be more permissive.
# note: cryptpad.fr permits web pages served via https: and vector: (element desktop app)
    set $frameAncestors "'self' https://${main_domain}";
# set $frameAncestors "'self' https: vector:";

    set $unsafe 0;
# the following assets are loaded via the sandbox domain
# they unfortunately still require exceptions to the sandboxing to work correctly.
    if ($uri ~ ^\/(sheet|doc|presentation)\/inner.html.*$) { set $unsafe 1; }
    if ($uri ~ ^\/common\/onlyoffice\/.*\/.*\.html.*$) { set $unsafe 1; }

# everything except the sandbox domain is a privileged scope, as they might be used to handle keys
    if ($host != $sandbox_domain) { set $unsafe 0; }
# this iframe is an exception. Office file formats are converted outside of the sandboxed scope
# because of bugs in Chromium-based browsers that incorrectly ignore headers that are supposed to enable
# the use of some modern APIs that we require when javascript is run in a cross-origin context.
# We've applied other sandboxing techniques to mitigate the risk of running WebAssembly in this privileged scope
    if ($uri ~ ^\/unsafeiframe\/inner\.html.*$) { set $unsafe 1; }

# privileged contexts allow a few more rights than unprivileged contexts, though limits are still applied
    if ($unsafe) {
        set $scriptSrc "'self' 'unsafe-eval' 'unsafe-inline' resource: https://${main_domain}";
    }

# Finally, set all the rules you composed above.
    add_header Content-Security-Policy "default-src 'none'; child-src $childSrc; worker-src $workerSrc; media-src $mediaSrc; style-src $styleSrc; script-src $scriptSrc; connect-src $connectSrc; font-src $fontSrc; img-src $imgSrc; frame-src $frameSrc; frame-ancestors $frameAncestors";

# The nodejs process can handle all traffic whether accessed over websocket or as static assets
# We prefer to serve static content from nginx directly and to leave the API server to handle
# the dynamic content that only it can manage. This is primarily an optimization
    location ^~ /cryptpad_websocket {
        proxy_pass http://localhost:3000;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

# WebSocket support (nginx 1.4)
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection upgrade;
    }

    location ^~ /customize.dist/ {
# This is needed in order to prevent infinite recursion between /customize/ and the root
    }
# try to load customizeable content via /customize/ and fall back to the default content
# located at /customize.dist/
# This is what allows you to override behaviour.
    location ^~ /customize/ {
        rewrite ^/customize/(.*)$ $1 break;
        try_files /customize/$uri /customize.dist/$uri;
    }

# /api/config is loaded once per page load and is used to retrieve
# the caching variable which is applied to every other resource
# which is loaded during that session.
    location ~ ^/api/.*$ {
        proxy_pass http://localhost:3000;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

# These settings prevent both NGINX and the API server
# from setting the same headers and creating duplicates
        proxy_hide_header Cross-Origin-Resource-Policy;
        add_header Cross-Origin-Resource-Policy cross-origin;
        proxy_hide_header Cross-Origin-Embedder-Policy;
        add_header Cross-Origin-Embedder-Policy require-corp;
    }

# encrypted blobs are immutable and are thus cached for a year
    location ^~ /blob/ {
        if ($request_method = 'OPTIONS') {
            add_header 'Access-Control-Allow-Origin' "${allowed_origins}";
            add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
            add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
            add_header 'Access-Control-Max-Age' 1728000;
            add_header 'Content-Type' 'application/octet-stream; charset=utf-8';
            add_header 'Content-Length' 0;
            return 204;
        }
        add_header X-Content-Type-Options nosniff;
        add_header Cache-Control max-age=31536000;
        add_header 'Access-Control-Allow-Origin' "${allowed_origins}";
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,Content-Length';
        add_header 'Access-Control-Expose-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,Content-Length';
        try_files $uri =404;
    }

# the "block-store" serves encrypted payloads containing users' drive keys
# these payloads are unlocked via login credentials. They are mutable
# and are thus never cached. They're small enough that it doesn't matter, in any case.
    location ^~ /block/ {
        add_header X-Content-Type-Options nosniff;
        add_header Cache-Control max-age=0;
        try_files $uri =404;
    }

# This block provides an alternative means of loading content
# otherwise only served via websocket. This is solely for debugging purposes,
# and is thus not allowed by default.
#location ^~ /datastore/ {
#add_header Cache-Control max-age=0;
#try_files $uri =404;
#}

# The nodejs server has some built-in forwarding rules to prevent
# URLs like /pad from resulting in a 404. This simply adds a trailing slash
# to a variety of applications.
    location ~ ^/(register|login|settings|user|pad|drive|poll|slide|code|whiteboard|file|media|profile|contacts|todo|filepicker|debug|kanban|sheet|support|admin|notifications|teams|calendar|presentation|doc|form|report|convert|checkup)$ {
        rewrite ^(.*)$ $1/ redirect;
    }

# Finally, serve anything the above exceptions don't govern.
    try_files /www/$uri /www/$uri/index.html /customize/$uri;
}