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Forked from michiel/cors-nginx.conf
Last active June 14, 2024 10:21
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Example Nginx configuration for adding cross-origin resource sharing (CORS) support to reverse proxied APIs
#
# CORS header support
#
# One way to use this is by placing it into a file called "cors_support"
# under your Nginx configuration directory and placing the following
# statement inside your **location** block(s):
#
# include cors_support;
#
# As of Nginx 1.7.5, add_header supports an "always" parameter which
# allows CORS to work if the backend returns 4xx or 5xx status code.
#
# For more information on CORS, please see: http://enable-cors.org/
# Forked from this Gist: https://gist.github.com/michiel/1064640
#
set $cors '';
if ($http_origin ~ '^https?://(localhost|www\.yourdomain\.com|www\.yourotherdomain\.com)') {
set $cors 'true';
}
if ($cors = 'true') {
add_header 'Access-Control-Allow-Origin' "$http_origin" always;
add_header 'Access-Control-Allow-Credentials' 'true' always;
add_header 'Access-Control-Allow-Methods' 'GET, POST, PUT, DELETE, OPTIONS' always;
add_header 'Access-Control-Allow-Headers' 'Accept,Authorization,Cache-Control,Content-Type,DNT,If-Modified-Since,Keep-Alive,Origin,User-Agent,X-Requested-With' always;
# required to be able to read Authorization header in frontend
#add_header 'Access-Control-Expose-Headers' 'Authorization' always;
}
if ($request_method = 'OPTIONS') {
# Tell client that this pre-flight info is valid for 20 days
add_header 'Access-Control-Max-Age' 1728000;
add_header 'Content-Type' 'text/plain charset=UTF-8';
add_header 'Content-Length' 0;
return 204;
}
@aamirmalek
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one silly question: I have nginx ingress which I installed using helm charts. Any idea where to put this annotation or snippet???

Curtly facing issue "Access to XMLHttpRequest at 'https://xxxxx/tenant/dashboard/ml/project?startDate=2021-11-23T09%3A37%3A16-06%3A00&endDate=2022-11-23T09%3A37%3A16-06%3A00&filterby=InProgress&page=1&offset=5' from origin 'https://xxxxxxxxx.io' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource."

@mylastore
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mylastore commented Jan 24, 2023

Justin Fortier

I am trying to do the same as you.
My BE is api.defaultseo.com, and FE defaultseo.com
When I log in from the FE, the refreshToken and Token are set on the BE only
I want to send the tokens to the FE on the response header
so when the FE requests access to a restricted BE route, FE sends the Token & Refresh Token to the BE.

Would you be able to help me fix the above? I also use MyVesta control panel to host the two websites on a droplet with Digital Ocean.

@diegoazh
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+1 for @mPanasiewicz 👍🏼

@mylastore
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Justin Fortier

I am trying to do the same as you. My BE is api.defaultseo.com, and FE defaultseo.com When I log in from the FE, the refreshToken and Token are set on the BE only I want to send the tokens to the FE on the response header so when the FE requests access to a restricted BE route, FE sends the Token & Refresh Token to the BE.

Would you be able to help me fix the above? I also use MyVesta control panel to host the two websites on a droplet with Digital Ocean.

I figure this out. It was not related to Nginx

It was on the cookies I just added the cookie attribute: domain: 'defaultseo.com' for example that was my issue.

@bitbay
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bitbay commented Oct 14, 2023

I'm just familiarizing myself with nginx configurations, but apparently

  • if You use an add_header directive in an if statement, no other add_header from outside the if seems to apply
  • empty strings used in add_header values aren't added/applied to the response

With these in mind, i only could made my case work (different methods allowed for different origins) was defining only variables inside the if statements.

set $allowed_headers '';
set $allowed_methods '';
set $allowed_credentials '';
set $allowed_origin '';
set $type '';
set $length '';

if ( $http_origin ~ "https://put-enabled" ) {
    set $allowed_origin $http_origin;
    set $allowed_methods 'OPTIONS, PUT';
    set $allowed_credentials false;
}

if ( $http_origin ~ "https://delete-enabled" ) {
    set $allowed_headers 'content-type, X-Requested-With';
    set $allowed_origin $http_origin;
    set $allowed_methods 'OPTIONS, DELETE';
    set $allowed_credentials true;
}

if ($request_method = OPTIONS) {
    set $allowed_headers 'content-type';
    set $type 'text/plain';
    set $length 0;
}

add_header Access-Control-Allow-Origin $allowed_origin always;
add_header Access-Control-Allow-Methods $allowed_methods always;
add_header Access-Control-Allow-Headers $allowed_headers always;
add_header Access-Control-Allow-Credentials $allowed_credentials always;
add_header Content-Type $type;
add_header Content-Length $length;

if ($request_method = OPTIONS) {
    return 204;
}

if ($request_method = POST) {
    return 404;
}

If You wonder why the POST returns a 404, it's because the navigator (chrome at least) ignores the Access-Control-Allow-Methods for POST requests. 🤷

@Pakbon
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Pakbon commented Nov 20, 2023

I'm just familiarizing myself with nginx configurations, but apparently

* if You use an `add_header` directive in an `if` statement, no other `add_header` from outside the `if` seems to apply

That's because IF is evil

@freultwah
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Having enabled the snippet, I scanned my site with nuclei and discovered that the regex '^https?://(localhost|www\.yourdomain\.com|www\.yourotherdomain\.com)' allows for suffixing the domain with anything, as in e.g. www.yourdomain.com.honeypot.com. I amended the regex with a '$' at the end (as in www\.yourotherdomain\.com)$' and it was smooth sailing.

@malithwee
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mPanasiewicz Works like a charm! thanks

@evtic229
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Hello @mPanasiewicz & @piotrekkr i saw you master niginx. Thank you for your good job I have a vps server with nginx and tomcat10..17, my frontend is not hosted on my vps. i have deployed my api java and test it throught postman and everything work but while i tried to fetch data from the frontend android and http this issue appear
Access to fetch at 'https://api.domain.com/directives/api/v1/file=' from origin 'https://domain.dev/' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

@Johnson1s
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y81mcnb3w9p5cep8

@nabtron
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nabtron commented Apr 1, 2024

My complete script that works both on my website and localhost:

  • Avoided if, mentioned in ifisevil
  • Fixed regex vulnerability, pointed out by @ejcx above.

In this script, my server is blog.mywebsite.com. It enabled CORS mywebsite.com and localhost to access requested resource.

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;

    server_name blog.mywebsite.com;
    root /var/www/ghost/system/nginx-root;

    ssl_certificate /etc/letsencrypt/blog.mywebsite.com/fullchain.cer;
    ssl_certificate_key /etc/letsencrypt/blog.mywebsite.com/blog.mywebsite.com.key;
    include /etc/nginx/snippets/ssl-params.conf;

    set $cors_origin "";
    set $cors_cred   "";
    set $cors_header "";
    set $cors_method "";

    if ($http_origin ~ '^https?://(localhost|mywebsite\.com)$') {
            set $cors_origin $http_origin;
            set $cors_cred   true;
            set $cors_header $http_access_control_request_headers;
            set $cors_method $http_access_control_request_method;
    }

    add_header Access-Control-Allow-Origin      $cors_origin;
    add_header Access-Control-Allow-Credentials $cors_cred;
    add_header Access-Control-Allow-Headers     $cors_header;
    add_header Access-Control-Allow-Methods     $cors_method;

    location / {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $http_host;
        proxy_pass http://127.0.0.1:2368;
    }

    location ~ /.well-known {
        allow all;
    }
    client_max_body_size 50m;
}

Your solution more or less worked for me using nginx version 1.12.2 Not sure which version of nginx you were using, but I couldn't run add_headers in my server block, but could in my location block which worked fine. Thanks.

add_header can work in http context .see http://nginx.org/en/docs/http/ngx_http_headers_module.html

worked like charm.

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