deps: update to github.com/opencontainers/selinux@v0.13.0

This new version includes the fixes for CVE-2025-52881, so we can remove the internal/third_party copy of the library we added in commit ed6b1693b8 ("selinux: use safe procfs API for labels") as well as the "replace" directive in go.mod (which is problematic for "go get" installs). Fixes: ed6b1693b8 ("selinux: use safe procfs API for labels") Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
2026-07-11 06:03:57 +08:00 · 2025-11-08 02:10:48 +11:00
parent 846835cce9
commit 96f1962f91
67 changed files with 2240 additions and 4909 deletions
@@ -0,0 +1,246 @@
+//go:build linux
+
+// SPDX-License-Identifier: MPL-2.0
+/*
+ * libpathrs: safe path resolution on Linux
+ * Copyright (C) 2019-2025 Aleksa Sarai <cyphar@cyphar.com>
+ * Copyright (C) 2019-2025 SUSE LLC
+ *
+ * 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 procfs provides a safe API for operating on /proc on Linux.
+package procfs
+
+import (
+	"os"
+	"runtime"
+
+	"cyphar.com/go-pathrs/internal/fdutils"
+	"cyphar.com/go-pathrs/internal/libpathrs"
+)
+
+// ProcBase is used with [ProcReadlink] and related functions to indicate what
+// /proc subpath path operations should be done relative to.
+type ProcBase struct {
+	inner libpathrs.ProcBase
+}
+
+var (
+	// ProcRoot indicates to use /proc. Note that this mode may be more
+	// expensive because we have to take steps to try to avoid leaking unmasked
+	// procfs handles, so you should use [ProcBaseSelf] if you can.
+	ProcRoot = ProcBase{inner: libpathrs.ProcRoot}
+	// ProcSelf indicates to use /proc/self. For most programs, this is the
+	// standard choice.
+	ProcSelf = ProcBase{inner: libpathrs.ProcSelf}
+	// ProcThreadSelf indicates to use /proc/thread-self. In multi-threaded
+	// programs where one thread has a different CLONE_FS, it is possible for
+	// /proc/self to point the wrong thread and so /proc/thread-self may be
+	// necessary.
+	ProcThreadSelf = ProcBase{inner: libpathrs.ProcThreadSelf}
+)
+
+// ProcPid returns a ProcBase which indicates to use /proc/$pid for the given
+// PID (or TID). Be aware that due to PID recycling, using this is generally
+// not safe except in certain circumstances. Namely:
+//
+//   - PID 1 (the init process), as that PID cannot ever get recycled.
+//   - Your current PID (though you should just use [ProcBaseSelf]).
+//   - Your current TID if you have used [runtime.LockOSThread] (though you
+//     should just use [ProcBaseThreadSelf]).
+//   - PIDs of child processes (as long as you are sure that no other part of
+//     your program incorrectly catches or ignores SIGCHLD, and that you do it
+//     *before* you call wait(2)or any equivalent method that could reap
+//     zombies).
+func ProcPid(pid int) ProcBase {
+	if pid < 0 || pid >= 1<<31 {
+		panic("invalid ProcBasePid value") // TODO: should this be an error?
+	}
+	return ProcBase{inner: libpathrs.ProcPid(uint32(pid))}
+}
+
+// ThreadCloser is a callback that needs to be called when you are done
+// operating on an [os.File] fetched using [Handle.OpenThreadSelf].
+//
+// [os.File]: https://pkg.go.dev/os#File
+type ThreadCloser func()
+
+// Handle is a wrapper around an *os.File handle to "/proc", which can be
+// used to do further procfs-related operations in a safe way.
+type Handle struct {
+	inner *os.File
+}
+
+// Close releases all internal resources for this [Handle].
+//
+// Note that if the handle is actually the global cached handle, this operation
+// is a no-op.
+func (proc *Handle) Close() error {
+	var err error
+	if proc.inner != nil {
+		err = proc.inner.Close()
+	}
+	return err
+}
+
+// OpenOption is a configuration function passed as an argument to [Open].
+type OpenOption func(*libpathrs.ProcfsOpenHow) error
+
+// UnmaskedProcRoot can be passed to [Open] to request an unmasked procfs
+// handle be created.
+//
+//	procfs, err := procfs.OpenRoot(procfs.UnmaskedProcRoot)
+func UnmaskedProcRoot(how *libpathrs.ProcfsOpenHow) error {
+	*how.Flags() |= libpathrs.ProcfsNewUnmasked
+	return nil
+}
+
+// Open creates a new [Handle] to a safe "/proc", based on the passed
+// configuration options (in the form of a series of [OpenOption]s).
+func Open(opts ...OpenOption) (*Handle, error) {
+	var how libpathrs.ProcfsOpenHow
+	for _, opt := range opts {
+		if err := opt(&how); err != nil {
+			return nil, err
+		}
+	}
+	fd, err := libpathrs.ProcfsOpen(&how)
+	if err != nil {
+		return nil, err
+	}
+	var procFile *os.File
+	if int(fd) >= 0 {
+		procFile = os.NewFile(fd, "/proc")
+	}
+	// TODO: Check that fd == PATHRS_PROC_DEFAULT_ROOTFD in the <0 case?
+	return &Handle{inner: procFile}, nil
+}
+
+// TODO: Switch to something fdutils.WithFileFd-like.
+func (proc *Handle) fd() int {
+	if proc.inner != nil {
+		return int(proc.inner.Fd())
+	}
+	return libpathrs.ProcDefaultRootFd
+}
+
+// TODO: Should we expose open?
+func (proc *Handle) open(base ProcBase, path string, flags int) (_ *os.File, Closer ThreadCloser, Err error) {
+	var closer ThreadCloser
+	if base == ProcThreadSelf {
+		runtime.LockOSThread()
+		closer = runtime.UnlockOSThread
+	}
+	defer func() {
+		if closer != nil && Err != nil {
+			closer()
+			Closer = nil
+		}
+	}()
+
+	fd, err := libpathrs.ProcOpenat(proc.fd(), base.inner, path, flags)
+	if err != nil {
+		return nil, nil, err
+	}
+	file, err := fdutils.MkFile(fd)
+	return file, closer, err
+}
+
+// OpenRoot safely opens a given path from inside /proc/.
+//
+// This function must only be used for accessing global information from procfs
+// (such as /proc/cpuinfo) or information about other processes (such as
+// /proc/1). Accessing your own process information should be done using
+// [Handle.OpenSelf] or [Handle.OpenThreadSelf].
+func (proc *Handle) OpenRoot(path string, flags int) (*os.File, error) {
+	file, closer, err := proc.open(ProcRoot, path, flags)
+	if closer != nil {
+		// should not happen
+		panic("non-zero closer returned from procOpen(ProcRoot)")
+	}
+	return file, err
+}
+
+// OpenSelf safely opens a given path from inside /proc/self/.
+//
+// This method is recommend for getting process information about the current
+// process for almost all Go processes *except* for cases where there are
+// [runtime.LockOSThread] threads that have changed some aspect of their state
+// (such as through unshare(CLONE_FS) or changing namespaces).
+//
+// For such non-heterogeneous processes, /proc/self may reference to a task
+// that has different state from the current goroutine and so it may be
+// preferable to use [Handle.OpenThreadSelf]. The same is true if a user
+// really wants to inspect the current OS thread's information (such as
+// /proc/thread-self/stack or /proc/thread-self/status which is always uniquely
+// per-thread).
+//
+// Unlike [Handle.OpenThreadSelf], this method does not involve locking
+// the goroutine to the current OS thread and so is simpler to use and
+// theoretically has slightly less overhead.
+//
+// [runtime.LockOSThread]: https://pkg.go.dev/runtime#LockOSThread
+func (proc *Handle) OpenSelf(path string, flags int) (*os.File, error) {
+	file, closer, err := proc.open(ProcSelf, path, flags)
+	if closer != nil {
+		// should not happen
+		panic("non-zero closer returned from procOpen(ProcSelf)")
+	}
+	return file, err
+}
+
+// OpenPid safely opens a given path from inside /proc/$pid/, where pid can be
+// either a PID or TID.
+//
+// This is effectively equivalent to calling [Handle.OpenRoot] with the
+// pid prefixed to the subpath.
+//
+// Be aware that due to PID recycling, using this is generally not safe except
+// in certain circumstances. See the documentation of [ProcPid] for more
+// details.
+func (proc *Handle) OpenPid(pid int, path string, flags int) (*os.File, error) {
+	file, closer, err := proc.open(ProcPid(pid), path, flags)
+	if closer != nil {
+		// should not happen
+		panic("non-zero closer returned from procOpen(ProcPidOpen)")
+	}
+	return file, err
+}
+
+// OpenThreadSelf safely opens a given path from inside /proc/thread-self/.
+//
+// Most Go processes have heterogeneous threads (all threads have most of the
+// same kernel state such as CLONE_FS) and so [Handle.OpenSelf] is
+// preferable for most users.
+//
+// For non-heterogeneous threads, or users that actually want thread-specific
+// information (such as /proc/thread-self/stack or /proc/thread-self/status),
+// this method is necessary.
+//
+// Because Go can change the running OS thread of your goroutine without notice
+// (and then subsequently kill the old thread), this method will lock the
+// current goroutine to the OS thread (with [runtime.LockOSThread]) and the
+// caller is responsible for unlocking the the OS thread with the
+// [ThreadCloser] callback once they are done using the returned file. This
+// callback MUST be called AFTER you have finished using the returned
+// [os.File]. This callback is completely separate to [os.File.Close], so it
+// must be called regardless of how you close the handle.
+//
+// [runtime.LockOSThread]: https://pkg.go.dev/runtime#LockOSThread
+// [os.File]: https://pkg.go.dev/os#File
+// [os.File.Close]: https://pkg.go.dev/os#File.Close
+func (proc *Handle) OpenThreadSelf(path string, flags int) (*os.File, ThreadCloser, error) {
+	return proc.open(ProcThreadSelf, path, flags)
+}
+
+// Readlink safely reads the contents of a symlink from the given procfs base.
+//
+// This is effectively equivalent to doing an Open*(O_PATH|O_NOFOLLOW) of the
+// path and then doing unix.Readlinkat(fd, ""), but with the benefit that
+// thread locking is not necessary for [ProcThreadSelf].
+func (proc *Handle) Readlink(base ProcBase, path string) (string, error) {
+	return libpathrs.ProcReadlinkat(proc.fd(), base.inner, path)
+}