1 files changed, 62 insertions, 0 deletions
diff --git a/lib/omni_auth/request_forgery_protection.rb b/lib/omni_auth/request_forgery_protection.rb
new file mode 100644
index 00000000000..cbbb686473c
--- /dev/null
+++ b/lib/omni_auth/request_forgery_protection.rb
@@ -0,0 +1,62 @@
+# Protects OmniAuth request phase against CSRF.
+
+module OmniAuth
+  # Based from ActionController::RequestForgeryProtection.
+  class RequestForgeryProtection
+    def initialize(env)
+      @env = env
+    end
+
+    def request
+      @request ||= ActionDispatch::Request.new(@env)
+    end
+
+    def session
+      request.session
+    end
+
+    def params
+      request.params
+    end
+
+    def call
+      verify_authenticity_token
+    end
+
+    def verify_authenticity_token
+      if !verified_request?
+        Rails.logger.warn "Can't verify CSRF token authenticity" if Rails.logger
+        handle_unverified_request
+      end
+    end
+
+    private
+
+    def protect_against_forgery?
+      ApplicationController.allow_forgery_protection
+    end
+
+    def request_forgery_protection_token
+      ApplicationController.request_forgery_protection_token
+    end
+
+    def forgery_protection_strategy
+      ApplicationController.forgery_protection_strategy
+    end
+
+    def verified_request?
+      !protect_against_forgery? || request.get? || request.head? ||
+        form_authenticity_token == params[request_forgery_protection_token] ||
+        form_authenticity_token == request.headers['X-CSRF-Token']
+    end
+
+    def handle_unverified_request
+      forgery_protection_strategy.new(self).handle_unverified_request
+    end
+
+    # Sets the token value for the current session.
+    def form_authenticity_token
+      session[:_csrf_token] ||= SecureRandom.base64(32)
+    end
+  end
+end