syncthing/lib/versioner/versioner.go
Jakob Borg f1f21bf220 lib/model, lib/versioner: Prevent symlink attack via versioning (fixes #4286)
Prior to this, the following is possible:

- Create a symlink "foo -> /somewhere", it gets synced
- Delete "foo", it gets versioned
- Create "foo/bar", it gets synced
- Delete "foo/bar", it gets versioned in "/somewhere/bar"

With this change, versioners should never version symlinks.
2017-08-07 07:57:10 +02:00

47 lines
1.3 KiB
Go

// Copyright (C) 2014 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
// Package versioner implements common interfaces for file versioning and a
// simple default versioning scheme.
package versioner
import (
"os"
"path/filepath"
"runtime"
)
type Versioner interface {
Archive(filePath string) error
}
var Factories = map[string]func(folderID string, folderDir string, params map[string]string) Versioner{}
const (
TimeFormat = "20060102-150405"
TimeGlob = "[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]-[0-9][0-9][0-9][0-9][0-9][0-9]" // glob pattern matching TimeFormat
)
func cleanSymlinks(dir string) {
if runtime.GOOS == "windows" {
// We don't do symlinks on Windows. Additionally, there may
// be things that look like symlinks that are not, which we
// should leave alone. Deduplicated files, for example.
return
}
filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.Mode()&os.ModeSymlink != 0 {
l.Infoln("Removing incorrectly versioned symlink", path)
os.Remove(path)
return filepath.SkipDir
}
return nil
})
}