File 0009-CVE-2020-8166.patch of Package rubygem-actionpack-5_1.36289

Index: actionpack-5.1.4/lib/action_controller/metal/request_forgery_protection.rb
===================================================================
--- actionpack-5.1.4.orig/lib/action_controller/metal/request_forgery_protection.rb
+++ actionpack-5.1.4/lib/action_controller/metal/request_forgery_protection.rb
@@ -301,13 +301,10 @@ module ActionController #:nodoc:
           action_path = normalize_action_path(action)
           per_form_csrf_token(session, action_path, method)
         else
-          real_csrf_token(session)
+          global_csrf_token(session)
         end
 
-        one_time_pad = SecureRandom.random_bytes(AUTHENTICITY_TOKEN_LENGTH)
-        encrypted_csrf_token = xor_byte_strings(one_time_pad, raw_token)
-        masked_token = one_time_pad + encrypted_csrf_token
-        Base64.strict_encode64(masked_token)
+        mask_token(raw_token)
       end
 
       # Checks the client's masked token to see if it matches the
@@ -337,7 +334,8 @@ module ActionController #:nodoc:
         elsif masked_token.length == AUTHENTICITY_TOKEN_LENGTH * 2
           csrf_token = unmask_token(masked_token)
 
-          compare_with_real_token(csrf_token, session) ||
+          compare_with_global_token(csrf_token, session) ||
+            compare_with_real_token(csrf_token, session) ||
             valid_per_form_csrf_token?(csrf_token, session)
         else
           false # Token is malformed.
@@ -352,10 +350,21 @@ module ActionController #:nodoc:
         xor_byte_strings(one_time_pad, encrypted_csrf_token)
       end
 
+      def mask_token(raw_token) # :doc:
+        one_time_pad = SecureRandom.random_bytes(AUTHENTICITY_TOKEN_LENGTH)
+        encrypted_csrf_token = xor_byte_strings(one_time_pad, raw_token)
+        masked_token = one_time_pad + encrypted_csrf_token
+        Base64.strict_encode64(masked_token)
+      end
+
       def compare_with_real_token(token, session) # :doc:
         ActiveSupport::SecurityUtils.secure_compare(token, real_csrf_token(session))
       end
 
+      def compare_with_global_token(token, session) # :doc:
+        ActiveSupport::SecurityUtils.secure_compare(token, global_csrf_token(session))
+      end
+
       def valid_per_form_csrf_token?(token, session) # :doc:
         if per_form_csrf_tokens
           correct_token = per_form_csrf_token(
@@ -376,10 +385,21 @@ module ActionController #:nodoc:
       end
 
       def per_form_csrf_token(session, action_path, method) # :doc:
+        csrf_token_hmac(session, [action_path, method.downcase].join("#"))
+      end
+
+      GLOBAL_CSRF_TOKEN_IDENTIFIER = "!real_csrf_token"
+      private_constant :GLOBAL_CSRF_TOKEN_IDENTIFIER
+
+      def global_csrf_token(session) # :doc:
+        csrf_token_hmac(session, GLOBAL_CSRF_TOKEN_IDENTIFIER)
+      end
+
+      def csrf_token_hmac(session, identifier) # :doc:
         OpenSSL::HMAC.digest(
           OpenSSL::Digest::SHA256.new,
           real_csrf_token(session),
-          [action_path, method.downcase].join("#")
+          identifier
         )
       end