Merge pull request #3634 from tsl0922/patch-grack-auth

fix http push 401 and 500 with some git clients

lib/gitlab/backend/grack_auth.rb

@@ -76,13 +76,17 @@ module Grack
     end
     def validate_get_request
-      project.public || can?(user, :download_code, project)
+      validate_request(@request.params['service'])
     end
     def validate_post_request
-      if @request.path_info.end_with?('git-upload-pack')
+      validate_request(File.basename(@request.path))
+    end
+
+    def validate_request(service)
+      if service == 'git-upload-pack'
         project.public || can?(user, :download_code, project)
-      elsif @request.path_info.end_with?('git-receive-pack')
+      elsif service == 'git-receive-pack'
         action = if project.protected_branch?(current_ref)
                    :push_code_to_protected_branches
                  else
@@ -107,7 +111,7 @@ module Grack
       end
       # Need to reset seek point
       @request.body.rewind
-      /refs\/heads\/([\w\.-]+)/.match(input).to_a.last
+      /refs\/heads\/([\w\.-]+)/n.match(input.force_encoding('ascii-8bit')).to_a.last
     end
     def project