Modify string_malformed middleware

lib/gitlab/middleware/handle_malformed_strings.rb

@@ -61,7 +61,7 @@ module Gitlab
 
         return false unless credentials
 
-        credentials_string_malformed?(credentials)
+        string_malformed?(credentials)
       end
 
       def param_has_null_byte?(value, depth = 0)
@@ -93,14 +93,8 @@ module Gitlab
         # We try to encode the string from ASCII-8BIT to UTF8. If we failed to do
         # so for certain characters in the string, those chars are probably incomplete
         # multibyte characters.
-        string.encode(Encoding::UTF_8).match?(NULL_BYTE_REGEX)
-      rescue ArgumentError, Encoding::UndefinedConversionError
-        # If we're here, we caught a malformed string. Return true
-        true
-      end
+        string.dup.force_encoding('UTF-8').match?(NULL_BYTE_REGEX)
 
-      def credentials_string_malformed?(string)
-        string.force_encoding('UTF-8').match?(NULL_BYTE_REGEX)
       rescue ArgumentError, Encoding::UndefinedConversionError
         # If we're here, we caught a malformed string. Return true
         true

spec/lib/gitlab/middleware/handle_malformed_strings_spec.rb

-# rubocop:disable Style/FrozenStringLiteralComment
+# frozen_string_literal: true
 require 'spec_helper'
 require "rack/test"
 

spec/requests/git_http_spec.rb

@@ -280,6 +280,16 @@ RSpec.describe 'Git HTTP requests' do
               project.add_developer(user)
             end
 
+            context 'when user is using password with special characters' do
+              it 'allows clones' do
+                user.update!(password: 'RçKszEwéC5kFnû∆f243fycGu§Gh9ftDj!U')
+
+                download(path, user: user.username, password: user.password) do |response|
+                  expect(response).to have_gitlab_http_status(:ok)
+                end
+              end
+            end
+
             context 'but the repo is disabled' do
               let(:project) { create(:project, :wiki_repo, :private, :repository_disabled, :wiki_enabled) }