oaut2_proxy

(This project was formerly known as Google Auth Proxy)

A reverse proxy that provides authentication using Providers (Google, Github, and others) to validate individual accounts, or a whole email domain.

Architecture

    _______       ______________       __________
    |Nginx| ----> |oauth2_proxy| ----> |upstream| 
    -------       --------------       ----------
                        ||
                        \/
              [provider OAuth2 API]

Installation

1. Download Prebuilt Binary or build from master with $ go get github.com/bitly/oauth2_proxy which should put the binary in $GOROOT/bin
2. Register an OAuth Application with a Provider
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 OAUTH2_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: oauth2_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

oauth2_proxy can be configured via config file, command line options or environment variables.

Config File

An example OAUTH2_PROXY.cfg config file is in the contrib directory. It can be used by specifying -config=/etc/oauth2_proxy.cfg

Command Line Options

Usage of oauth2_proxy:
  -authenticated-emails-file="": authenticate against emails via file (one per line)
  -client-id="": the OAuth Client ID: ie: "123456.apps.googleusercontent.com"
  -client-secret="": the 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-refresh=0: refresh the cookie when less than this much time remains before expiration; 0 to disable
  -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
  -validate-url="": Access token validation endpoint
  -version=false: print version string

See below for provider specific options

Environment variables

The environment variables OAUTH2_PROXY_CLIENT_ID, OAUTH2_PROXY_CLIENT_SECRET, OAUTH2_PROXY_COOKIE_SECRET, OAUTH2_PROXY_COOKIE_DOMAIN and OAUTH2_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 oauth2_proxy on port 4180. oauth2_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 oauth2_proxy would look like this:

./oauth2_proxy \
   --google-apps-domain="yourcompany.com"  \
   --upstream=http://127.0.0.1:8080/ \
   --cookie-secret=... \
   --cookie-secure=true \
   --client-id=... \
   --client-secret=...

Endpoint Documentation

OAuth2 Proxy responds directly to the following endpoints. All other endpoints will be proxied upstream when authenticated.

• /robots.txt - returns a 200 OK response that disallows all User-agents from all paths; see robotstxt.org for more info
• /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

OAuth2 Proxy Proxy logs requests to stdout in a format similar to Apache Combined Log.

<REMOTE_ADDRESS> - <user@domain.com> [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

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

• google - (default) Google

• myusa - The MyUSA authentication service (GitHub)

• linkedin - The LinkedIn Sign In service.

• github - Via [Github][https://github.com/settings/developers] OAuth App. Also supports restricting via org and team.

  -github-org="": restrict logins to members of this organisation -github-team="": restrict logins to members of this team

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.