server {
    listen 80;
    server_name _;
    root /var/www/html/public;
    index index.php;

    client_max_body_size 100m;

    # The nginx version number is nobody's business but ours.
    server_tokens off;

    # Baseline hardening for every response. `always` so they survive error
    # responses too. NOTE: nginx does not merge add_header across levels —
    # a location that declares any add_header of its own inherits none of
    # these, so /protected-files/ below repeats them deliberately.
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;

    location / {
        try_files $uri $uri/ /index.php?$query_string;
    }

    # Protected file serving: PHP authorizes, nginx streams (brief §3).
    # PHP responds with X-Accel-Redirect: /protected-files/<path>.
    #
    # This is the only location that returns bytes someone else uploaded,
    # so it gets the strictest headers in the file. `sandbox` puts anything
    # rendered as a document into an opaque origin with scripts disabled —
    # if a payload ever does reach here with a renderable content type
    # (FileThumbnailController's allowlist is the primary defence), it
    # cannot touch this app's origin or the viewer's session. Images loaded
    # as subresources are unaffected: a CSP on a subresource response never
    # creates a browsing context, so thumbnails and previews still render.
    # `^~` so this prefix beats the `\.php$` regex below: without it a
    # protected path ending in .php would be handed to the PHP handler
    # instead of streaming under the sandbox headers this block sets.
    location ^~ /protected-files/ {
        internal;
        alias /var/www/html/storage/app/files/;

        add_header X-Content-Type-Options "nosniff" always;
        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header Referrer-Policy "strict-origin-when-cross-origin" always;
        add_header Content-Security-Policy "sandbox; default-src 'none'" always;
    }

    location ~ \.php$ {
        # Never hand a path to PHP-FPM that isn't a real script on disk:
        # without this, any URI ending in .php reaches the interpreter and
        # PATH_INFO resolution decides what actually runs.
        try_files $uri =404;

        fastcgi_pass app:9000;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
        include fastcgi_params;
        fastcgi_buffer_size 32k;
        fastcgi_buffers 8 32k;
    }

    location ~ /\.(?!well-known) {
        deny all;
    }
}