deps: update to github.com/cyphar/filepath-securejoin@v0.4.1

This release includes a minor breaking API change that requires us to
rework the types of our wrappers, but there is no practical behaviour
change.

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>

go.mod

@@ -12,7 +12,7 @@ require (
 	github.com/cilium/ebpf v0.17.1
 	github.com/containerd/console v1.0.4
 	github.com/coreos/go-systemd/v22 v22.5.0
-	github.com/cyphar/filepath-securejoin v0.3.6
+	github.com/cyphar/filepath-securejoin v0.4.1
 	github.com/docker/go-units v0.5.0
 	github.com/godbus/dbus/v5 v5.1.0
 	github.com/moby/sys/capability v0.4.0

go.sum

@@ -10,8 +10,8 @@ github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSV
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/cpuguy83/go-md2man/v2 v2.0.5 h1:ZtcqGrnekaHpVLArFSe4HK5DoKx1T0rq2DwVB0alcyc=
 github.com/cpuguy83/go-md2man/v2 v2.0.5/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
-github.com/cyphar/filepath-securejoin v0.3.6 h1:4d9N5ykBnSp5Xn2JkhocYDkOpURL/18CYMpo6xB9uWM=
-github.com/cyphar/filepath-securejoin v0.3.6/go.mod h1:Sdj7gXlvMcPZsbhwhQ33GguGLDGQL7h7bg04C/+u9jI=
+github.com/cyphar/filepath-securejoin v0.4.1 h1:JyxxyPEaktOD+GAnqIqTf9A8tHyAG22rowi7HkoSU1s=
+github.com/cyphar/filepath-securejoin v0.4.1/go.mod h1:Sdj7gXlvMcPZsbhwhQ33GguGLDGQL7h7bg04C/+u9jI=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=

libcontainer/utils/utils_unix.go

@@ -287,9 +287,6 @@ func IsLexicallyInRoot(root, path string) bool {
 // try to detect any symlink components in the path while we are doing the
 // MkdirAll.
 //
-// NOTE: Unlike os.MkdirAll, mode is not Go's os.FileMode, it is the unix mode
-// (the suid/sgid/sticky bits are not the same as for os.FileMode).
-//
 // NOTE: If unsafePath is a subpath of root, we assume that you have already
 // called SecureJoin and so we use the provided path verbatim without resolving
 // any symlinks (this is done in a way that avoids symlink-exchange races).
@@ -300,7 +297,7 @@ func IsLexicallyInRoot(root, path string) bool {
 // handling if unsafePath has already been scoped within the rootfs (this is
 // needed for a lot of runc callers and fixing this would require reworking a
 // lot of path logic).
-func MkdirAllInRootOpen(root, unsafePath string, mode uint32) (_ *os.File, Err error) {
+func MkdirAllInRootOpen(root, unsafePath string, mode os.FileMode) (_ *os.File, Err error) {
 	// If the path is already "within" the root, get the path relative to the
 	// root and use that as the unsafe path. This is necessary because a lot of
 	// MkdirAllInRootOpen callers have already done SecureJoin, and refactoring
@@ -334,12 +331,12 @@ func MkdirAllInRootOpen(root, unsafePath string, mode uint32) (_ *os.File, Err e
 	}
 	defer rootDir.Close()
 
-	return securejoin.MkdirAllHandle(rootDir, unsafePath, int(mode))
+	return securejoin.MkdirAllHandle(rootDir, unsafePath, mode)
 }
 
 // MkdirAllInRoot is a wrapper around MkdirAllInRootOpen which closes the
 // returned handle, for callers that don't need to use it.
-func MkdirAllInRoot(root, unsafePath string, mode uint32) error {
+func MkdirAllInRoot(root, unsafePath string, mode os.FileMode) error {
 	f, err := MkdirAllInRootOpen(root, unsafePath, mode)
 	if err == nil {
 		_ = f.Close()

vendor/github.com/cyphar/filepath-securejoin/CHANGELOG.md

@@ -6,6 +6,51 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased] ##
 
+## [0.4.1] - 2025-01-28 ##
+
+### Fixed ###
+- The restrictions added for `root` paths passed to `SecureJoin` in 0.4.0 was
+  found to be too strict and caused some regressions when folks tried to
+  update, so this restriction has been relaxed to only return an error if the
+  path contains a `..` component. We still recommend users use `filepath.Clean`
+  (and even `filepath.EvalSymlinks`) on the `root` path they are using, but at
+  least you will no longer be punished for "trivial" unclean paths.
+
+## [0.4.0] - 2025-01-13 ##
+
+### Breaking ####
+- `SecureJoin(VFS)` will now return an error if the provided `root` is not a
+  `filepath.Clean`'d path.
+
+  While it is ultimately the responsibility of the caller to ensure the root is
+  a safe path to use, passing a path like `/symlink/..` as a root would result
+  in the `SecureJoin`'d path being placed in `/` even though `/symlink/..`
+  might be a different directory, and so we should more strongly discourage
+  such usage.
+
+  All major users of `securejoin.SecureJoin` already ensure that the paths they
+  provide are safe (and this is ultimately a question of user error), but
+  removing this foot-gun is probably a good idea. Of course, this is
+  necessarily a breaking API change (though we expect no real users to be
+  affected by it).
+
+  Thanks to [Erik Sjölund](https://github.com/eriksjolund), who initially
+  reported this issue as a possible security issue.
+
+- `MkdirAll` and `MkdirHandle` now take an `os.FileMode`-style mode argument
+  instead of a raw `unix.S_*`-style mode argument, which may cause compile-time
+  type errors depending on how you use `filepath-securejoin`. For most users,
+  there will be no change in behaviour aside from the type change (as the
+  bottom `0o777` bits are the same in both formats, and most users are probably
+  only using those bits).
+
+  However, if you were using `unix.S_ISVTX` to set the sticky bit with
+  `MkdirAll(Handle)` you will need to switch to `os.ModeSticky` otherwise you
+  will get a runtime error with this update. In addition, the error message you
+  will get from passing `unix.S_ISUID` and `unix.S_ISGID` will be different as
+  they are treated as invalid bits now (note that previously passing said bits
+  was also an error).
+
 ## [0.3.6] - 2024-12-17 ##
 
 ### Compatibility ###
@@ -193,7 +238,9 @@ This is our first release of `github.com/cyphar/filepath-securejoin`,
 containing a full implementation with a coverage of 93.5% (the only missing
 cases are the error cases, which are hard to mocktest at the moment).
 
-[Unreleased]: https://github.com/cyphar/filepath-securejoin/compare/v0.3.6...HEAD
+[Unreleased]: https://github.com/cyphar/filepath-securejoin/compare/v0.4.1...HEAD
+[0.4.1]: https://github.com/cyphar/filepath-securejoin/compare/v0.4.0...v0.4.1
+[0.4.0]: https://github.com/cyphar/filepath-securejoin/compare/v0.3.6...v0.4.0
 [0.3.6]: https://github.com/cyphar/filepath-securejoin/compare/v0.3.5...v0.3.6
 [0.3.5]: https://github.com/cyphar/filepath-securejoin/compare/v0.3.4...v0.3.5
 [0.3.4]: https://github.com/cyphar/filepath-securejoin/compare/v0.3.3...v0.3.4

vendor/github.com/cyphar/filepath-securejoin/VERSION

@@ -1 +1 @@
-0.3.6
+0.4.1

vendor/github.com/cyphar/filepath-securejoin/join.go

@@ -1,5 +1,5 @@
 // Copyright (C) 2014-2015 Docker Inc & Go Authors. All rights reserved.
-// Copyright (C) 2017-2024 SUSE LLC. All rights reserved.
+// Copyright (C) 2017-2025 SUSE LLC. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
@@ -24,6 +24,31 @@ func IsNotExist(err error) bool {
 	return errors.Is(err, os.ErrNotExist) || errors.Is(err, syscall.ENOTDIR) || errors.Is(err, syscall.ENOENT)
 }
 
+// errUnsafeRoot is returned if the user provides SecureJoinVFS with a path
+// that contains ".." components.
+var errUnsafeRoot = errors.New("root path provided to SecureJoin contains '..' components")
+
+// stripVolume just gets rid of the Windows volume included in a path. Based on
+// some godbolt tests, the Go compiler is smart enough to make this a no-op on
+// Linux.
+func stripVolume(path string) string {
+	return path[len(filepath.VolumeName(path)):]
+}
+
+// hasDotDot checks if the path contains ".." components in a platform-agnostic
+// way.
+func hasDotDot(path string) bool {
+	// If we are on Windows, strip any volume letters. It turns out that
+	// C:..\foo may (or may not) be a valid pathname and we need to handle that
+	// leading "..".
+	path = stripVolume(path)
+	// Look for "/../" in the path, but we need to handle leading and trailing
+	// ".."s by adding separators. Doing this with filepath.Separator is ugly
+	// so just convert to Unix-style "/" first.
+	path = filepath.ToSlash(path)
+	return strings.Contains("/"+path+"/", "/../")
+}
+
 // SecureJoinVFS joins the two given path components (similar to [filepath.Join]) except
 // that the returned path is guaranteed to be scoped inside the provided root
 // path (when evaluated). Any symbolic links in the path are evaluated with the
@@ -46,7 +71,22 @@ func IsNotExist(err error) bool {
 // provided via direct input or when evaluating symlinks. Therefore:
 //
 // "C:\Temp" + "D:\path\to\file.txt" results in "C:\Temp\path\to\file.txt"
+//
+// If the provided root is not [filepath.Clean] then an error will be returned,
+// as such root paths are bordering on somewhat unsafe and using such paths is
+// not best practice. We also strongly suggest that any root path is first
+// fully resolved using [filepath.EvalSymlinks] or otherwise constructed to
+// avoid containing symlink components. Of course, the root also *must not* be
+// attacker-controlled.
 func SecureJoinVFS(root, unsafePath string, vfs VFS) (string, error) {
+	// The root path must not contain ".." components, otherwise when we join
+	// the subpath we will end up with a weird path. We could work around this
+	// in other ways but users shouldn't be giving us non-lexical root paths in
+	// the first place.
+	if hasDotDot(root) {
+		return "", errUnsafeRoot
+	}
+
 	// Use the os.* VFS implementation if none was specified.
 	if vfs == nil {
 		vfs = osVFS{}
@@ -59,9 +99,10 @@ func SecureJoinVFS(root, unsafePath string, vfs VFS) (string, error) {
 		linksWalked   int
 	)
 	for remainingPath != "" {
-		if v := filepath.VolumeName(remainingPath); v != "" {
-			remainingPath = remainingPath[len(v):]
-		}
+		// On Windows, if we managed to end up at a path referencing a volume,
+		// drop the volume to make sure we don't end up with broken paths or
+		// escaping the root volume.
+		remainingPath = stripVolume(remainingPath)
 
 		// Get the next path component.
 		var part string

vendor/github.com/cyphar/filepath-securejoin/mkdir_linux.go

@@ -21,6 +21,33 @@ var (
 	errPossibleAttack = errors.New("possible attack detected")
 )
 
+// modePermExt is like os.ModePerm except that it also includes the set[ug]id
+// and sticky bits.
+const modePermExt = os.ModePerm | os.ModeSetuid | os.ModeSetgid | os.ModeSticky
+
+//nolint:cyclop // this function needs to handle a lot of cases
+func toUnixMode(mode os.FileMode) (uint32, error) {
+	sysMode := uint32(mode.Perm())
+	if mode&os.ModeSetuid != 0 {
+		sysMode |= unix.S_ISUID
+	}
+	if mode&os.ModeSetgid != 0 {
+		sysMode |= unix.S_ISGID
+	}
+	if mode&os.ModeSticky != 0 {
+		sysMode |= unix.S_ISVTX
+	}
+	// We don't allow file type bits.
+	if mode&os.ModeType != 0 {
+		return 0, fmt.Errorf("%w %+.3o (%s): type bits not permitted", errInvalidMode, mode, mode)
+	}
+	// We don't allow other unknown modes.
+	if mode&^modePermExt != 0 || sysMode&unix.S_IFMT != 0 {
+		return 0, fmt.Errorf("%w %+.3o (%s): unknown mode bits", errInvalidMode, mode, mode)
+	}
+	return sysMode, nil
+}
+
 // MkdirAllHandle is equivalent to [MkdirAll], except that it is safer to use
 // in two respects:
 //
@@ -39,17 +66,17 @@ var (
 // a brand new lookup of unsafePath (such as with [SecureJoin] or openat2) after
 // doing [MkdirAll]. If you intend to open the directory after creating it, you
 // should use MkdirAllHandle.
-func MkdirAllHandle(root *os.File, unsafePath string, mode int) (_ *os.File, Err error) {
-	// Make sure there are no os.FileMode bits set.
-	if mode&^0o7777 != 0 {
-		return nil, fmt.Errorf("%w for mkdir 0o%.3o", errInvalidMode, mode)
+func MkdirAllHandle(root *os.File, unsafePath string, mode os.FileMode) (_ *os.File, Err error) {
+	unixMode, err := toUnixMode(mode)
+	if err != nil {
+		return nil, err
 	}
 	// On Linux, mkdirat(2) (and os.Mkdir) silently ignore the suid and sgid
 	// bits. We could also silently ignore them but since we have very few
 	// users it seems more prudent to return an error so users notice that
 	// these bits will not be set.
-	if mode&^0o1777 != 0 {
-		return nil, fmt.Errorf("%w for mkdir 0o%.3o: suid and sgid are ignored by mkdir", errInvalidMode, mode)
+	if unixMode&^0o1777 != 0 {
+		return nil, fmt.Errorf("%w for mkdir %+.3o: suid and sgid are ignored by mkdir", errInvalidMode, mode)
 	}
 
 	// Try to open as much of the path as possible.
@@ -104,9 +131,6 @@ func MkdirAllHandle(root *os.File, unsafePath string, mode int) (_ *os.File, Err
 		return nil, fmt.Errorf("%w: yet-to-be-created path %q contains '..' components", unix.ENOENT, remainingPath)
 	}
 
-	// Make sure the mode doesn't have any type bits.
-	mode &^= unix.S_IFMT
-
 	// Create the remaining components.
 	for _, part := range remainingParts {
 		switch part {
@@ -123,7 +147,7 @@ func MkdirAllHandle(root *os.File, unsafePath string, mode int) (_ *os.File, Err
 		// directory at the same time as us. In that case, just continue on as
 		// if we created it (if the created inode is not a directory, the
 		// following open call will fail).
-		if err := unix.Mkdirat(int(currentDir.Fd()), part, uint32(mode)); err != nil && !errors.Is(err, unix.EEXIST) {
+		if err := unix.Mkdirat(int(currentDir.Fd()), part, unixMode); err != nil && !errors.Is(err, unix.EEXIST) {
 			err = &os.PathError{Op: "mkdirat", Path: currentDir.Name() + "/" + part, Err: err}
 			// Make the error a bit nicer if the directory is dead.
 			if deadErr := isDeadInode(currentDir); deadErr != nil {
@@ -196,10 +220,7 @@ func MkdirAllHandle(root *os.File, unsafePath string, mode int) (_ *os.File, Err
 // If you plan to open the directory after you have created it or want to use
 // an open directory handle as the root, you should use [MkdirAllHandle] instead.
 // This function is a wrapper around [MkdirAllHandle].
-//
-// NOTE: The mode argument must be set the unix mode bits (unix.S_I...), not
-// the Go generic mode bits ([os.FileMode]...).
-func MkdirAll(root, unsafePath string, mode int) error {
+func MkdirAll(root, unsafePath string, mode os.FileMode) error {
 	rootDir, err := os.OpenFile(root, unix.O_PATH|unix.O_DIRECTORY|unix.O_CLOEXEC, 0)
 	if err != nil {
 		return err

vendor/modules.txt

@@ -27,7 +27,7 @@ github.com/coreos/go-systemd/v22/dbus
 # github.com/cpuguy83/go-md2man/v2 v2.0.5
 ## explicit; go 1.11
 github.com/cpuguy83/go-md2man/v2/md2man
-# github.com/cyphar/filepath-securejoin v0.3.6
+# github.com/cyphar/filepath-securejoin v0.4.1
 ## explicit; go 1.18
 github.com/cyphar/filepath-securejoin
 # github.com/docker/go-units v0.5.0