Method Join

internal/safepaths/absolute.go:38–57

Join an absolute path with elements to create a new Absolute path, or error. A PathTraversalError will be returned if the joined path would traverse outside of the base Absolute path. Note that this does not handle symlinks.

(elem ...string)

// A PathTraversalError will be returned if the joined path would traverse outside of
// the base Absolute path. Note that this does not handle symlinks.
func (a Absolute) Join(elem ...string) (Absolute, error) {
	joinedAbsolutePath, err := ParseAbsolute(filepath.Join(append([]string{a.path}, elem...)...))
	if err != nil {
		return Absolute{}, fmt.Errorf("failed to parse joined path: %w", err)
	}

	isSubpath, err := joinedAbsolutePath.isSubpathOf(a)
	if err != nil {
		return Absolute{}, err
	}

	if !isSubpath {
		return Absolute{}, PathTraversalError{
			Base:  a,
			Elems: elem,
		}
	}

	return joinedAbsolutePath, nil
}

func (a Absolute) isSubpathOf(dir Absolute) (bool, error) {
	relativePath, err := filepath.Rel(dir.path, a.path)