Ports omniauth-jwt gem onto GitLab OmniAuth Strategies suite

Gemfile

@@ -51,7 +51,6 @@ gem 'omniauth-shibboleth', '~> 1.2.0'
 gem 'omniauth-twitter', '~> 1.4'
 gem 'omniauth_crowd', '~> 2.2.0'
 gem 'omniauth-authentiq', '~> 0.3.1'
-gem 'omniauth-jwt', '~> 0.0.2'
 gem 'rack-oauth2', '~> 1.2.1'
 gem 'jwt', '~> 1.5.6'
 

Gemfile.lock

@@ -555,9 +555,6 @@ GEM
       jwt (>= 1.5)
       omniauth (>= 1.1.1)
       omniauth-oauth2 (>= 1.5)
-    omniauth-jwt (0.0.2)
-      jwt
-      omniauth (~> 1.1)
     omniauth-kerberos (0.3.0)
       omniauth-multipassword
       timfel-krb5-auth (~> 0.8)
@@ -1119,7 +1116,6 @@ DEPENDENCIES
   omniauth-github (~> 1.1.1)
   omniauth-gitlab (~> 1.0.2)
   omniauth-google-oauth2 (~> 0.5.3)
-  omniauth-jwt (~> 0.0.2)
   omniauth-kerberos (~> 0.3.0)
   omniauth-oauth2-generic (~> 0.2.2)
   omniauth-saml (~> 1.10)

changelogs/unreleased/add-jwt-strategy-to-gitlab-suite.yml

+---
+title: Ports omniauth-jwt gem onto GitLab OmniAuth Strategies suite
+merge_request: 18580
+author:
+type: fixed

config/gitlab.yml.example

@@ -532,7 +532,7 @@ production: &base
       #             required_claims: ["name", "email"],
       #             info_map: { name: "name", email: "email" },
       #             auth_url: 'https://example.com/',
-      #             valid_within: nil,
+      #             valid_within: null,
       #           }
       #   }
       # - { name: 'saml',
@@ -823,7 +823,7 @@ test:
                   required_claims: ["name", "email"],
                   info_map: { name: "name", email: "email" },
                   auth_url: 'https://example.com/',
-                  valid_within: nil,
+                  valid_within: null,
                 }
         }
       - { name: 'auth0',

config/initializers/omniauth.rb

@@ -25,5 +25,6 @@ end
 module OmniAuth
   module Strategies
     autoload :Bitbucket, Rails.root.join('lib', 'omni_auth', 'strategies', 'bitbucket')
+    autoload :Jwt, Rails.root.join('lib', 'omni_auth', 'strategies', 'jwt')
   end
 end

doc/administration/auth/jwt.md

@@ -50,7 +50,7 @@ JWT will provide you with a secret key for you to use.
                 required_claims: ["name", "email"],
                 info_map: { name: "name", email: "email" },
                 auth_url: 'https://example.com/',
-                valid_within: nil,
+                valid_within: null,
               }
       }
     ```

lib/omni_auth/strategies/jwt.rb

+require 'omniauth'
+require 'jwt'
+
+module OmniAuth
+  module Strategies
+    class JWT
+      ClaimInvalid = Class.new(StandardError)
+
+      include OmniAuth::Strategy
+
+      args [:secret]
+
+      option :secret, nil
+      option :algorithm, 'HS256'
+      option :uid_claim, 'email'
+      option :required_claims, %w(name email)
+      option :info_map, { name: "name", email: "email" }
+      option :auth_url, nil
+      option :valid_within, nil
+
+      uid { decoded[options.uid_claim] }
+
+      extra do
+        { raw_info: decoded }
+      end
+
+      info do
+        options.info_map.each_with_object({}) do |(k, v), h|
+          h[k.to_s] = decoded[v.to_s]
+        end
+      end
+
+      def request_phase
+        redirect options.auth_url
+      end
+
+      def decoded
+        @decoded ||= ::JWT.decode(request.params['jwt'], options.secret, options.algorithm).first
+
+        (options.required_claims || []).each do |field|
+          raise ClaimInvalid, "Missing required '#{field}' claim" unless @decoded.key?(field.to_s)
+        end
+
+        raise ClaimInvalid, "Missing required 'iat' claim" if options.valid_within && !@decoded["iat"]
+
+        if options.valid_within && (Time.now.to_i - @decoded["iat"]).abs > options.valid_within
+          raise ClaimInvalid, "'iat' timestamp claim is too skewed from present"
+        end
+
+        @decoded
+      end
+
+      def callback_phase
+        super
+      rescue ClaimInvalid => e
+        fail! :claim_invalid, e
+      end
+    end
+
+    class Jwt < JWT; end
+  end
+end