Function untar

decompress_tar.go:14–147

untar is a shared helper for untarring an archive. The reader should provide an uncompressed view of the tar archive.

(input io.Reader, dst, src string, dir bool, umask os.FileMode, fileSizeLimit int64, filesLimit int)

// untar is a shared helper for untarring an archive. The reader should provide
// an uncompressed view of the tar archive.
func untar(input io.Reader, dst, src string, dir bool, umask os.FileMode, fileSizeLimit int64, filesLimit int) error {
	tarR := tar.NewReader(input)
	done := false
	dirHdrs := []*tar.Header{}
	now := time.Now()

	var (
		fileSize   int64
		filesCount int
	)

	for {
		if filesLimit > 0 {
			filesCount++
			if filesCount > filesLimit {
				return fmt.Errorf("tar archive contains too many files: %d > %d", filesCount, filesLimit)
			}
		}

		hdr, err := tarR.Next()
		if err == io.EOF {
			if !done {
				// Empty archive
				return fmt.Errorf("empty archive: %s", src)
			}

			break
		}
		if err != nil {
			return err
		}

		if hdr.Typeflag == tar.TypeXGlobalHeader || hdr.Typeflag == tar.TypeXHeader {
			// don't unpack extended headers as files
			continue
		}

		path := dst
		if dir {
			// Disallow parent traversal
			if containsDotDot(hdr.Name) {
				return fmt.Errorf("entry contains '..': %s", hdr.Name)
			}

			path = filepath.Join(path, hdr.Name)
		}

		fileInfo := hdr.FileInfo()

		fileSize += fileInfo.Size()

		if fileSizeLimit > 0 && fileSize > fileSizeLimit {
			return fmt.Errorf("tar archive larger than limit: %d", fileSizeLimit)
		}

		if fileInfo.IsDir() {
			if !dir {
				return fmt.Errorf("expected a single file: %s", src)