vendor: bump runc to f000fe11

vendor/github.com/opencontainers/runc/libcontainer/rootfs_linux.go

@@ -46,6 +46,7 @@ func prepareRootfs(pipe io.ReadWriter, iConfig *initConfig) (err error) {
 		return newSystemErrorWithCause(err, "preparing rootfs")
 	}
 
+	setupDev := needsSetupDev(config)
 	for _, m := range config.Mounts {
 		for _, precmd := range m.PremountCmds {
 			if err := mountCmd(precmd); err != nil {
@@ -64,8 +65,6 @@ func prepareRootfs(pipe io.ReadWriter, iConfig *initConfig) (err error) {
 		}
 	}
 
-	setupDev := needsSetupDev(config)
-
 	if setupDev {
 		if err := createDevices(config); err != nil {
 			return newSystemErrorWithCause(err, "creating device nodes")
@@ -153,6 +152,26 @@ func finalizeRootfs(config *configs.Config) (err error) {
 	return nil
 }
 
+// /tmp has to be mounted as private to allow MS_MOVE to work in all situations
+func prepareTmp(topTmpDir string) (string, error) {
+	tmpdir, err := ioutil.TempDir(topTmpDir, "runctop")
+	if err != nil {
+		return "", err
+	}
+	if err := unix.Mount(tmpdir, tmpdir, "bind", unix.MS_BIND, ""); err != nil {
+		return "", err
+	}
+	if err := unix.Mount("", tmpdir, "", uintptr(unix.MS_PRIVATE), ""); err != nil {
+		return "", err
+	}
+	return tmpdir, nil
+}
+
+func cleanupTmp(tmpdir string) error {
+	unix.Unmount(tmpdir, 0)
+	return os.RemoveAll(tmpdir)
+}
+
 func mountCmd(cmd configs.Command) error {
 	command := exec.Command(cmd.Path, cmd.Args[:]...)
 	command.Env = cmd.Env
@@ -200,7 +219,12 @@ func mountToRootfs(m *configs.Mount, rootfs, mountLabel string) error {
 			}
 		}
 		if copyUp {
-			tmpDir, err = ioutil.TempDir("/tmp", "runctmpdir")
+			tmpdir, err := prepareTmp("/tmp")
+			if err != nil {
+				return newSystemErrorWithCause(err, "tmpcopyup: failed to setup tmpdir")
+			}
+			defer cleanupTmp(tmpdir)
+			tmpDir, err = ioutil.TempDir(tmpdir, "runctmpdir")
 			if err != nil {
 				return newSystemErrorWithCause(err, "tmpcopyup: failed to create tmpdir")
 			}
@@ -397,6 +421,7 @@ func checkMountDestination(rootfs, dest string) error {
 		"/proc/stat",
 		"/proc/swaps",
 		"/proc/uptime",
+		"/proc/loadavg",
 		"/proc/net/dev",
 	}
 	for _, valid := range validDestinations {
@@ -413,7 +438,7 @@ func checkMountDestination(rootfs, dest string) error {
 		if err != nil {
 			return err
 		}
-		if path == "." || !strings.HasPrefix(path, "..") {
+		if path != "." && !strings.HasPrefix(path, "..") {
 			return fmt.Errorf("%q cannot be mounted because it is located inside %q", dest, invalid)
 		}
 	}
@@ -803,10 +828,7 @@ func remount(m *configs.Mount, rootfs string) error {
 	if !strings.HasPrefix(dest, rootfs) {
 		dest = filepath.Join(rootfs, dest)
 	}
-	if err := unix.Mount(m.Source, dest, m.Device, uintptr(m.Flags|unix.MS_REMOUNT), ""); err != nil {
-		return err
-	}
-	return nil
+	return unix.Mount(m.Source, dest, m.Device, uintptr(m.Flags|unix.MS_REMOUNT), "")
 }
 
 // Do the mount operation followed by additional mounts required to take care