Merge pull request #40429 from natematykiewicz/openssl_fixed_length_secure_compare

Speed up `ActiveSupport::SecurityUtils.fixed_length_secure_compare`

activesupport/CHANGELOG.md

@@ -1,3 +1,8 @@
+*   Speed up `ActiveSupport::SecurityUtils.fixed_length_secure_compare` by using
+    `OpenSSL.fixed_length_secure_compare`, if available.
+
+    *Nate Matykiewicz*
+
 *   `ActiveSupport::Cache::MemCacheStore` now checks `ENV["MEMCACHE_SERVERS"]` before falling back to `"localhost:11211"` if configured without any addresses.
 
     ```ruby

activesupport/lib/active_support/security_utils.rb

@@ -6,6 +6,12 @@ module ActiveSupport
     #
     # The values compared should be of fixed length, such as strings
     # that have already been processed by HMAC. Raises in case of length mismatch.
+
+    if defined?(OpenSSL.fixed_length_secure_compare)
+      def fixed_length_secure_compare(a, b)
+        OpenSSL.fixed_length_secure_compare(a, b)
+      end
+    else
       def fixed_length_secure_compare(a, b)
         raise ArgumentError, "string length mismatch." unless a.bytesize == b.bytesize
 
@@ -15,6 +21,7 @@ module ActiveSupport
         b.each_byte { |byte| res |= byte ^ l.shift }
         res == 0
       end
+    end
     module_function :fixed_length_secure_compare
 
     # Secure string comparison for strings of variable length.