noonien/google-auth-proxy repository overview

⁠google_auth_proxy

A reverse proxy that provides authentication using Google and other OAuth2 providers to validate individual accounts, or a whole google apps domain.

⁠Architecture

    _______       ___________________       __________
    |Nginx| ----> |google_auth_proxy| ----> |upstream| 
    -------       -------------------       ----------
                          ||
                          \/
                  [google oauth2 api]

⁠Installation

1. Download Prebuilt Binary⁠ or build from master with $ go get github.com/bitly/google_auth_proxy which should put the binary in $GOROOT/bin
2. Register an OAuth Application with Google
3. Configure Google Auth Proxy using config file, command line options, or environment variables
4. Deploy behind a SSL endpoint (example provided for Nginx)

⁠OAuth Configuration

You will need to register an OAuth application with Google (or another provider⁠), and configure it with Redirect URI(s) for the domain you intend to run google_auth_proxy on.

For Google, the registration steps are:

1. Create a new project: https://console.developers.google.com/project⁠
2. Under "APIs & Auth", choose "Credentials"
3. Now, choose "Create new Client ID"
   • The Application Type should be Web application
   • Enter your domain in the Authorized Javascript Origins https://internal.yourcompany.com
   • Enter the correct Authorized Redirect URL https://internal.yourcompany.com/oauth2/callback
     • NOTE: google_auth_proxy will only callback on the path /oauth2/callback
4. Under "APIs & Auth" choose "Consent Screen"
   • Fill in the necessary fields and Save (this is required)
5. Take note of the Client ID and Client Secret

For LinkedIn, the registration steps are:

1. Create a new project: https://www.linkedin.com/secure/developer⁠
2. In the OAuth User Agreement section:
   • In default scope, select r_basicprofile and r_emailaddress.
   • In "OAuth 2.0 Redirect URLs", enter https://internal.yourcompany.com/oauth2/callback
3. Fill in the remaining required fields and Save.
4. Take note of the Consumer Key / API Key and Consumer Secret / Secret Key

⁠Configuration

google_auth_proxy can be configured via config file⁠, command line options⁠ or environment variables⁠.

⁠Config File

An example google_auth_proxy.cfg⁠ config file is in the contrib directory. It can be used by specifying -config=/etc/google_auth_proxy.cfg

⁠Command Line Options

Usage of google_auth_proxy:
  -authenticated-emails-file="": authenticate against emails via file (one per line)
  -client-id="": the Google OAuth Client ID: ie: "123456.apps.googleusercontent.com"
  -client-secret="": the OAuth Client Secret
  -config="": path to config file
  -cookie-domain="": an optional cookie domain to force cookies to (ie: .yourcompany.com)*
  -cookie-expire=168h0m0s: expire timeframe for cookie
  -cookie-httponly=true: set HttpOnly cookie flag
  -cookie-https-only=true: set secure (HTTPS) cookies (deprecated. use --cookie-secure setting)
  -cookie-secret="": the seed string for secure cookies
  -cookie-secure=true: set secure (HTTPS) cookie flag
  -custom-templates-dir="": path to custom html templates
  -display-htpasswd-form=true: display username / password login form if an htpasswd file is provided
  -google-apps-domain=: authenticate against the given Google apps domain (may be given multiple times)
  -htpasswd-file="": additionally authenticate against a htpasswd file. Entries must be created with "htpasswd -s" for SHA encryption
  -http-address="127.0.0.1:4180": [http://]<addr>:<port> or unix://<path> to listen on for HTTP clients
  -login-url="": Authentication endpoint
  -pass-access-token=false: pass OAuth access_token to upstream via X-Forwarded-Access-Token header
  -pass-basic-auth=true: pass HTTP Basic Auth, X-Forwarded-User and X-Forwarded-Email information to upstream
  -pass-host-header=true: pass the request Host Header to upstream
  -profile-url="": Profile access endpoint
  -provider="": Oauth provider (defaults to Google)
  -redeem-url="": Token redemption endpoint
  -redirect-url="": the OAuth Redirect URL. ie: "https://internalapp.yourcompany.com/oauth2/callback"
  -request-logging=true: Log requests to stdout
  -scope="": Oauth scope specification
  -skip-auth-regex=: bypass authentication for requests path's that match (may be given multiple times)
  -upstream=: the http url(s) of the upstream endpoint. If multiple, routing is based on path
  -version=false: print version string

⁠Environment variables

The environment variables GOOGLE_AUTH_PROXY_CLIENT_ID, GOOGLE_AUTH_PROXY_CLIENT_SECRET, GOOGLE_AUTH_PROXY_COOKIE_SECRET, GOOGLE_AUTH_PROXY_COOKIE_DOMAIN and GOOGLE_AUTH_PROXY_COOKIE_EXPIRE can be used in place of the corresponding command-line arguments.

⁠Example Nginx Configuration

This example has a Nginx⁠ SSL endpoint proxying to google_auth_proxy on port 4180. google_auth_proxy then authenticates requests for an upstream application running on port 8080. The external endpoint for this example would be https://internal.yourcompany.com/.

An example Nginx config follows. Note the use of Strict-Transport-Security header to pin requests to SSL via HSTS⁠:

server {
    listen 443 default ssl;
    server_name internal.yourcompany.com;
    ssl_certificate /path/to/cert.pem;
    ssl_certificate_key /path/to/cert.key;
    add_header Strict-Transport-Security max-age=1209600;

    location / {
        proxy_pass http://127.0.0.1:4180;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Scheme $scheme;
        proxy_connect_timeout 1;
        proxy_send_timeout 30;
        proxy_read_timeout 30;
    }
}

The command line to run google_auth_proxy would look like this:

./google_auth_proxy \
   --google-apps-domain="yourcompany.com"  \
   --upstream=http://127.0.0.1:8080/ \
   --cookie-secret=... \
   --cookie-secure=true \
   --client-id=... \
   --client-secret=...

⁠Endpoint Documentation

Google Auth Proxy responds directly to the following endpoints. All other endpoints will be proxied upstream when authenticated.

• /ping - returns an 200 OK response
• /oauth2/sign_in - the login page, which also doubles as a sign out page (it clears cookies)
• /oauth2/start - a URL that will redirect to start the OAuth cycle
• /oauth2/callback - the URL used at the end of the OAuth cycle. The oauth app will be configured with this ass the callback url.

⁠Logging Format

Google Auth Proxy logs requests to stdout in a format similar to Apache Combined Log.

<REMOTE_ADDRESS> - <[email protected]> [19/Mar/2015:17:20:19 -0400] <HOST_HEADER> GET <UPSTREAM_HOST> "/path/" HTTP/1.1 "<USER_AGENT>" <RESPONSE_CODE> <RESPONSE_BYTES> <REQUEST_DURATION>

⁠Providers other than Google

Other providers besides Google can be specified by the providers flag/config directive. Right now this includes:

• myusa - The MyUSA⁠ authentication service (GitHub⁠)
• linkedin - The LinkedIn⁠ Sign In service.

⁠Adding a new Provider

Follow the examples in the providers package⁠ to define a new Provider instance. Add a new case to providers.New()⁠ to allow the auth proxy to use the new Provider.