1 files changed, 3 insertions, 2 deletions
diff --git a/lib/api/helpers/file_upload_helpers.rb b/lib/api/helpers/file_upload_helpers.rb
index c5fb291a2b7..dd551ec2976 100644
--- a/lib/api/helpers/file_upload_helpers.rb
+++ b/lib/api/helpers/file_upload_helpers.rb
@@ -4,11 +4,12 @@ module API
   module Helpers
     module FileUploadHelpers
       def file_is_valid?
-        params[:file] && params[:file]['tempfile'].respond_to?(:read)
+        filename = params[:file]&.original_filename
+        filename && ImportExportUploader::EXTENSION_WHITELIST.include?(File.extname(filename).delete('.'))
       end
 
       def validate_file!
-        render_api_error!('Uploaded file is invalid', 400) unless file_is_valid?
+        render_api_error!({ error: _('You need to upload a GitLab project export archive (ending in .gz).') }, 422) unless file_is_valid?
       end
     end
   end