1 files changed, 23 insertions, 10 deletions
diff --git a/lib/gitlab/import_export/command_line_util.rb b/lib/gitlab/import_export/command_line_util.rb
index d681f39f00b..e2f365fcbf8 100644
--- a/lib/gitlab/import_export/command_line_util.rb
+++ b/lib/gitlab/import_export/command_line_util.rb
@@ -5,8 +5,11 @@ module Gitlab
     module CommandLineUtil
       UNTAR_MASK = 'u+rwX,go+rX,go-w'
       DEFAULT_DIR_MODE = 0700
+      CLEAN_DIR_IGNORE_FILE_NAMES = %w[. ..].freeze
 
-      FileOversizedError = Class.new(StandardError)
+      CommandLineUtilError = Class.new(StandardError)
+      FileOversizedError = Class.new(CommandLineUtilError)
+      HardLinkError = Class.new(CommandLineUtilError)
 
       def tar_czf(archive:, dir:)
         tar_with_options(archive: archive, dir: dir, options: 'czf')
@@ -90,7 +93,7 @@ module Gitlab
       def untar_with_options(archive:, dir:, options:)
         execute_cmd(%W(tar -#{options} #{archive} -C #{dir}))
         execute_cmd(%W(chmod -R #{UNTAR_MASK} #{dir}))
-        remove_symlinks(dir)
+        clean_extraction_dir!(dir)
       end
 
       # rubocop:disable Gitlab/ModuleWithInstanceVariables
@@ -122,17 +125,27 @@ module Gitlab
         true
       end
 
-      def remove_symlinks(dir)
-        ignore_file_names = %w[. ..]
-
+      # Scans and cleans the directory tree.
+      # Symlinks are considered legal but are removed.
+      # Files sharing hard links are considered illegal and the directory will be removed
+      # and a `HardLinkError` exception will be raised.
+      #
+      # @raise [HardLinkError] if there multiple hard links to the same file detected.
+      # @return [Boolean] true
+      def clean_extraction_dir!(dir)
         # Using File::FNM_DOTMATCH to also delete symlinks starting with "."
-        Dir.glob("#{dir}/**/*", File::FNM_DOTMATCH)
-          .reject { |f| ignore_file_names.include?(File.basename(f)) }
-          .each do |filepath|
-            FileUtils.rm(filepath) if File.lstat(filepath).symlink?
-          end
+        Dir.glob("#{dir}/**/*", File::FNM_DOTMATCH).each do |filepath|
+          next if CLEAN_DIR_IGNORE_FILE_NAMES.include?(File.basename(filepath))
+
+          raise HardLinkError, 'File shares hard link' if Gitlab::Utils::FileInfo.shares_hard_link?(filepath)
+
+          FileUtils.rm(filepath) if Gitlab::Utils::FileInfo.linked?(filepath)
+        end
 
         true
+      rescue HardLinkError
+        FileUtils.remove_dir(dir)
+        raise
       end
     end
   end