Move RootPath to fs package
This moves the RootPath function out of the archive package and into the fs package for external use. Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This commit is contained in:
Michael Crosby
99
fs/path.go
99
fs/path.go
@@ -7,6 +7,12 @@ import (
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"os"
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"path/filepath"
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"strings"
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"github.com/pkg/errors"
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)
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var (
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errTooManyLinks = errors.New("too many links")
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)
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type currentPath struct {
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@@ -160,3 +166,96 @@ func nextPath(ctx context.Context, pathC <-chan *currentPath) (*currentPath, err
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return p, nil
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}
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}
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// RootPath joins a path with a root, evaluating and bounding any
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// symlink to the root directory.
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func RootPath(root, path string) (string, error) {
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if path == "" {
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return root, nil
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}
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var linksWalked int // to protect against cycles
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for {
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i := linksWalked
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newpath, err := walkLinks(root, path, &linksWalked)
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if err != nil {
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return "", err
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}
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path = newpath
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if i == linksWalked {
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newpath = filepath.Join("/", newpath)
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if path == newpath {
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return filepath.Join(root, newpath), nil
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}
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path = newpath
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}
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}
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}
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func walkLink(root, path string, linksWalked *int) (newpath string, islink bool, err error) {
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if *linksWalked > 255 {
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return "", false, errTooManyLinks
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}
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path = filepath.Join("/", path)
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if path == "/" {
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return path, false, nil
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}
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realPath := filepath.Join(root, path)
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fi, err := os.Lstat(realPath)
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if err != nil {
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// If path does not yet exist, treat as non-symlink
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if os.IsNotExist(err) {
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return path, false, nil
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}
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return "", false, err
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}
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if fi.Mode()&os.ModeSymlink == 0 {
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return path, false, nil
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}
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newpath, err = os.Readlink(realPath)
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if err != nil {
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return "", false, err
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}
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if filepath.IsAbs(newpath) && strings.HasPrefix(newpath, root) {
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newpath = newpath[:len(root)]
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if !strings.HasPrefix(newpath, "/") {
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newpath = "/" + newpath
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}
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}
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*linksWalked++
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return newpath, true, nil
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}
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func walkLinks(root, path string, linksWalked *int) (string, error) {
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switch dir, file := filepath.Split(path); {
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case dir == "":
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newpath, _, err := walkLink(root, file, linksWalked)
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return newpath, err
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case file == "":
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if os.IsPathSeparator(dir[len(dir)-1]) {
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if dir == "/" {
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return dir, nil
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}
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return walkLinks(root, dir[:len(dir)-1], linksWalked)
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}
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newpath, _, err := walkLink(root, dir, linksWalked)
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return newpath, err
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default:
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newdir, err := walkLinks(root, dir, linksWalked)
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if err != nil {
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return "", err
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}
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newpath, islink, err := walkLink(root, filepath.Join(newdir, file), linksWalked)
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if err != nil {
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return "", err
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}
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if !islink {
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return newpath, nil
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}
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if filepath.IsAbs(newpath) {
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return newpath, nil
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}
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return filepath.Join(newdir, newpath), nil
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}
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}
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295
fs/path_test.go
Normal file
295
fs/path_test.go
Normal file
@@ -0,0 +1,295 @@
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// +build !windows
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package fs
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import (
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"io/ioutil"
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"os"
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"path/filepath"
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"testing"
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"github.com/containerd/containerd/fs/fstest"
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"github.com/pkg/errors"
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)
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type rootCheck struct {
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unresolved string
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expected string
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scope func(string) string
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cause error
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}
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func TestRootPath(t *testing.T) {
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tests := []struct {
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name string
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apply fstest.Applier
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checks []rootCheck
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scope func(string) (string, error)
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}{
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{
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name: "SymlinkAbsolute",
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apply: Symlink("/b", "fs/a/d"),
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checks: Check("fs/a/d/c/data", "b/c/data"),
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},
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{
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name: "SymlinkRelativePath",
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apply: Symlink("a", "fs/i"),
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checks: Check("fs/i", "fs/a"),
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},
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{
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name: "SymlinkSkipSymlinksOutsideScope",
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apply: Symlink("realdir", "linkdir"),
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checks: CheckWithScope("foo/bar", "foo/bar", "linkdir"),
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},
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{
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name: "SymlinkLastLink",
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apply: Symlink("/b", "fs/a/d"),
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checks: Check("fs/a/d", "b"),
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},
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{
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name: "SymlinkRelativeLinkChangeScope",
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apply: Symlink("../b", "fs/a/e"),
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checks: CheckAll(
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Check("fs/a/e/c/data", "fs/b/c/data"),
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CheckWithScope("e", "b", "fs/a"), // Original return
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),
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},
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{
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name: "SymlinkDeepRelativeLinkChangeScope",
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apply: Symlink("../../../../test", "fs/a/f"),
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checks: CheckAll(
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Check("fs/a/f", "test"), // Original return
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CheckWithScope("a/f", "test", "fs"), // Original return
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),
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},
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{
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name: "SymlinkRelativeLinkChain",
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apply: fstest.Apply(
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Symlink("../g", "fs/b/h"),
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fstest.Symlink("../../../../../../../../../../../../root", "fs/g"),
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),
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checks: Check("fs/b/h", "root"),
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},
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{
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name: "SymlinkBreakoutPath",
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apply: Symlink("../i/a", "fs/j/k"),
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checks: CheckWithScope("k", "i/a", "fs/j"),
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},
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{
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name: "SymlinkToRoot",
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apply: Symlink("/", "foo"),
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checks: Check("foo", ""),
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},
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{
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name: "SymlinkSlashDotdot",
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apply: Symlink("/../../", "foo"),
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checks: Check("foo", ""),
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},
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{
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name: "SymlinkDotdot",
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apply: Symlink("../../", "foo"),
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checks: Check("foo", ""),
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},
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{
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name: "SymlinkRelativePath2",
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apply: Symlink("baz/target", "bar/foo"),
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checks: Check("bar/foo", "bar/baz/target"),
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},
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{
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name: "SymlinkScopeLink",
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apply: fstest.Apply(
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Symlink("root2", "root"),
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Symlink("../bar", "root2/foo"),
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),
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checks: CheckWithScope("foo", "bar", "root"),
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},
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{
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name: "SymlinkSelf",
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apply: fstest.Apply(
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Symlink("foo", "root/foo"),
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),
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checks: ErrorWithScope("foo", "root", errTooManyLinks),
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},
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{
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name: "SymlinkCircular",
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apply: fstest.Apply(
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Symlink("foo", "bar"),
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Symlink("bar", "foo"),
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),
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checks: ErrorWithScope("foo", "", errTooManyLinks), //TODO: Test for circular error
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},
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{
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name: "SymlinkCircularUnderRoot",
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apply: fstest.Apply(
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Symlink("baz", "root/bar"),
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Symlink("../bak", "root/baz"),
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Symlink("/bar", "root/bak"),
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),
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checks: ErrorWithScope("bar", "root", errTooManyLinks), // TODO: Test for circular error
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},
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{
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name: "SymlinkComplexChain",
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apply: fstest.Apply(
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fstest.CreateDir("root2", 0777),
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Symlink("root2", "root"),
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Symlink("r/s", "root/a"),
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Symlink("../root/t", "root/r"),
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Symlink("/../u", "root/root/t/s/b"),
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Symlink(".", "root/u/c"),
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Symlink("../v", "root/u/x/y"),
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Symlink("/../w", "root/u/v"),
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),
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checks: CheckWithScope("a/b/c/x/y/z", "w/z", "root"), // Original return
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},
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{
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name: "SymlinkBreakoutNonExistent",
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apply: fstest.Apply(
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Symlink("/", "root/slash"),
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Symlink("/idontexist/../slash", "root/sym"),
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),
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checks: CheckWithScope("sym/file", "file", "root"),
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},
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{
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name: "SymlinkNoLexicalCleaning",
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apply: fstest.Apply(
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Symlink("/foo/bar", "root/sym"),
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Symlink("/sym/../baz", "root/hello"),
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),
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checks: CheckWithScope("hello", "foo/baz", "root"),
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},
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}
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for _, test := range tests {
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t.Run(test.name, makeRootPathTest(t, test.apply, test.checks))
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}
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// Add related tests which are unable to follow same pattern
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t.Run("SymlinkRootScope", testRootPathSymlinkRootScope)
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t.Run("SymlinkEmpty", testRootPathSymlinkEmpty)
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}
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func testRootPathSymlinkRootScope(t *testing.T) {
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tmpdir, err := ioutil.TempDir("", "TestFollowSymlinkRootScope")
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if err != nil {
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t.Fatal(err)
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}
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defer os.RemoveAll(tmpdir)
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expected, err := filepath.EvalSymlinks(tmpdir)
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if err != nil {
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t.Fatal(err)
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}
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rewrite, err := RootPath("/", tmpdir)
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if err != nil {
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t.Fatal(err)
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}
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if rewrite != expected {
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t.Fatalf("expected %q got %q", expected, rewrite)
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}
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}
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func testRootPathSymlinkEmpty(t *testing.T) {
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wd, err := os.Getwd()
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if err != nil {
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t.Fatal(err)
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}
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res, err := RootPath(wd, "")
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if err != nil {
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t.Fatal(err)
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}
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if res != wd {
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t.Fatalf("expected %q got %q", wd, res)
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}
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}
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func makeRootPathTest(t *testing.T, apply fstest.Applier, checks []rootCheck) func(t *testing.T) {
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return func(t *testing.T) {
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applyDir, err := ioutil.TempDir("", "test-root-path-")
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if err != nil {
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t.Fatalf("Unable to make temp directory: %+v", err)
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}
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defer os.RemoveAll(applyDir)
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if apply != nil {
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if err := apply.Apply(applyDir); err != nil {
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t.Fatalf("Apply failed: %+v", err)
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}
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}
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for i, check := range checks {
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root := applyDir
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if check.scope != nil {
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root = check.scope(root)
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}
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actual, err := RootPath(root, check.unresolved)
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if check.cause != nil {
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if err == nil {
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t.Errorf("(Check %d) Expected error %q, %q evaluated as %q", i+1, check.cause.Error(), check.unresolved, actual)
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}
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if errors.Cause(err) != check.cause {
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t.Fatalf("(Check %d) Failed to evaluate root path: %+v", i+1, err)
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}
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} else {
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expected := filepath.Join(root, check.expected)
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if err != nil {
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t.Fatalf("(Check %d) Failed to evaluate root path: %+v", i+1, err)
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}
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if actual != expected {
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t.Errorf("(Check %d) Unexpected evaluated path %q, expected %q", i+1, actual, expected)
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}
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}
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}
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}
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}
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func Check(unresolved, expected string) []rootCheck {
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return []rootCheck{
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{
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unresolved: unresolved,
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expected: expected,
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},
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}
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}
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func CheckWithScope(unresolved, expected, scope string) []rootCheck {
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return []rootCheck{
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{
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unresolved: unresolved,
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expected: expected,
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scope: func(root string) string {
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return filepath.Join(root, scope)
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},
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},
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}
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}
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func ErrorWithScope(unresolved, scope string, cause error) []rootCheck {
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return []rootCheck{
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{
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unresolved: unresolved,
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cause: cause,
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scope: func(root string) string {
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return filepath.Join(root, scope)
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},
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},
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}
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}
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func CheckAll(checks ...[]rootCheck) []rootCheck {
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all := make([]rootCheck, 0, len(checks))
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for _, c := range checks {
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all = append(all, c...)
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}
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return all
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}
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func Symlink(oldname, newname string) fstest.Applier {
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dir := filepath.Dir(newname)
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if dir != "" {
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return fstest.Apply(
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fstest.CreateDir(dir, 0755),
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fstest.Symlink(oldname, newname),
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)
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}
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return fstest.Symlink(oldname, newname)
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}
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Reference in New Issue
Block a user