1 files changed, 58 insertions, 0 deletions
diff --git a/lib/bulk_imports/file_downloads/validations.rb b/lib/bulk_imports/file_downloads/validations.rb
new file mode 100644
index 00000000000..ae94267a6e8
--- /dev/null
+++ b/lib/bulk_imports/file_downloads/validations.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+
+module BulkImports
+  module FileDownloads
+    module Validations
+      def raise_error(message)
+        raise NotImplementedError
+      end
+
+      def filepath
+        raise NotImplementedError
+      end
+
+      def file_size_limit
+        raise NotImplementedError
+      end
+
+      def response_headers
+        raise NotImplementedError
+      end
+
+      private
+
+      def validate_filepath
+        Gitlab::Utils.check_path_traversal!(filepath)
+      end
+
+      def validate_content_type
+        content_type = response_headers['content-type']
+
+        raise_error('Invalid content type') if content_type.blank? || allowed_content_types.exclude?(content_type)
+      end
+
+      def validate_symlink
+        return unless File.lstat(filepath).symlink?
+
+        File.delete(filepath)
+        raise_error 'Invalid downloaded file'
+      end
+
+      def validate_content_length
+        validate_size!(response_headers['content-length'])
+      end
+
+      def validate_size!(size)
+        if size.blank?
+          raise_error 'Missing content-length header'
+        elsif size.to_i > file_size_limit
+          raise_error format(
+            "File size %{size} exceeds limit of %{limit}",
+            size: ActiveSupport::NumberHelper.number_to_human_size(size),
+            limit: ActiveSupport::NumberHelper.number_to_human_size(file_size_limit)
+          )
+        end
+      end
+    end
+  end
+end