Decouple cgroup devices handling

This commit separates the functionality of setting cgroup device
rules out of libct/cgroups to libct/cgroups/devices package. This
package, if imported, sets the function variables in libct/cgroups and
libct/cgroups/systemd, so that a cgroup manager can use those to manage
devices. If those function variables are nil (when libct/cgroups/devices
are not imported), a cgroup manager returns the ErrDevicesUnsupported
in case any device rules are set in Resources.

It also consolidates the code from libct/cgroups/ebpf and
libct/cgroups/ebpf/devicefilter into libct/cgroups/devices.

Moved some tests in libct/cg/sd that require device management to
libct/sd/devices.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/cgroups/cgroups.go

@@ -1,9 +1,24 @@
 package cgroups
 
 import (
+	"errors"
+
 	"github.com/opencontainers/runc/libcontainer/configs"
 )
 
+var (
+	// ErrDevicesUnsupported is an error returned when a cgroup manager
+	// is not configured to set device rules.
+	ErrDevicesUnsupported = errors.New("cgroup manager is not configured to set device rules")
+
+	// DevicesSetV1 and DevicesSetV2 are functions to set devices for
+	// cgroup v1 and v2, respectively. Unless libcontainer/cgroups/devices
+	// package is imported, it is set to nil, so cgroup managers can't
+	// manage devices.
+	DevicesSetV1 func(path string, r *configs.Resources) error
+	DevicesSetV2 func(path string, r *configs.Resources) error
+)
+
 type Manager interface {
 	// Apply creates a cgroup, if not yet created, and adds a process
 	// with the specified pid into that cgroup.  A special value of -1

libcontainer/cgroups/devices/devicefilter.go

@@ -1,10 +1,10 @@
-// Package devicefilter contains eBPF device filter program
+// Implements creation of eBPF device filter program.
 //
-// The implementation is based on https://github.com/containers/crun/blob/0.10.2/src/libcrun/ebpf.c
+// Based on https://github.com/containers/crun/blob/0.10.2/src/libcrun/ebpf.c
 //
 // Although ebpf.c is originally licensed under LGPL-3.0-or-later, the author (Giuseppe Scrivano)
 // agreed to relicense the file in Apache License 2.0: https://github.com/opencontainers/runc/issues/2144#issuecomment-543116397
-package devicefilter
+package devices
 
 import (
 	"errors"
@@ -13,7 +13,6 @@ import (
 	"strconv"
 
 	"github.com/cilium/ebpf/asm"
-	devicesemulator "github.com/opencontainers/runc/libcontainer/cgroups/devices"
 	"github.com/opencontainers/runc/libcontainer/devices"
 	"golang.org/x/sys/unix"
 )
@@ -30,7 +29,7 @@ func DeviceFilter(rules []*devices.Rule) (asm.Instructions, string, error) {
 	// gives us a guarantee that the behaviour of devices filtering is the same
 	// as cgroupv1, including security hardenings to avoid misconfiguration
 	// (such as punching holes in wildcard rules).
-	emu := new(devicesemulator.Emulator)
+	emu := new(Emulator)
 	for _, rule := range rules {
 		if err := emu.Apply(*rule); err != nil {
 			return nil, "", err

libcontainer/cgroups/devices/devicefilter_test.go

@@ -1,4 +1,4 @@
-package devicefilter
+package devices
 
 import (
 	"strings"

libcontainer/cgroups/devices/devices.go

@@ -0,0 +1,16 @@
+// Package devices contains functionality to manage cgroup devices, which
+// is exposed indirectly via libcontainer/cgroups managers.
+//
+// To enable cgroup managers to manage devices, this package must be imported.
+package devices
+
+import (
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
+)
+
+func init() {
+	cgroups.DevicesSetV1 = setV1
+	cgroups.DevicesSetV2 = setV2
+	systemd.GenerateDeviceProps = systemdProperties
+}

libcontainer/cgroups/devices/ebpf_linux.go

@@ -1,4 +1,4 @@
-package ebpf
+package devices
 
 import (
 	"errors"

libcontainer/cgroups/devices/systemd.go

@@ -0,0 +1,233 @@
+package devices
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	systemdDbus "github.com/coreos/go-systemd/v22/dbus"
+	"github.com/godbus/dbus/v5"
+	"github.com/sirupsen/logrus"
+
+	"github.com/opencontainers/runc/libcontainer/configs"
+	"github.com/opencontainers/runc/libcontainer/devices"
+)
+
+// systemdProperties takes the configured device rules and generates a
+// corresponding set of systemd properties to configure the devices correctly.
+func systemdProperties(r *configs.Resources) ([]systemdDbus.Property, error) {
+	if r.SkipDevices {
+		return nil, nil
+	}
+
+	properties := []systemdDbus.Property{
+		// Always run in the strictest white-list mode.
+		newProp("DevicePolicy", "strict"),
+		// Empty the DeviceAllow array before filling it.
+		newProp("DeviceAllow", []deviceAllowEntry{}),
+	}
+
+	// Figure out the set of rules.
+	configEmu := Emulator{}
+	for _, rule := range r.Devices {
+		if err := configEmu.Apply(*rule); err != nil {
+			return nil, fmt.Errorf("unable to apply rule for systemd: %w", err)
+		}
+	}
+	// systemd doesn't support blacklists. So we log a warning, and tell
+	// systemd to act as a deny-all whitelist. This ruleset will be replaced
+	// with our normal fallback code. This may result in spurious errors, but
+	// the only other option is to error out here.
+	if configEmu.IsBlacklist() {
+		// However, if we're dealing with an allow-all rule then we can do it.
+		if configEmu.IsAllowAll() {
+			return allowAllDevices(), nil
+		}
+		logrus.Warn("systemd doesn't support blacklist device rules -- applying temporary deny-all rule")
+		return properties, nil
+	}
+
+	// Now generate the set of rules we actually need to apply. Unlike the
+	// normal devices cgroup, in "strict" mode systemd defaults to a deny-all
+	// whitelist which is the default for devices.Emulator.
+	finalRules, err := configEmu.Rules()
+	if err != nil {
+		return nil, fmt.Errorf("unable to get simplified rules for systemd: %w", err)
+	}
+	var deviceAllowList []deviceAllowEntry
+	for _, rule := range finalRules {
+		if !rule.Allow {
+			// Should never happen.
+			return nil, fmt.Errorf("[internal error] cannot add deny rule to systemd DeviceAllow list: %v", *rule)
+		}
+		switch rule.Type {
+		case devices.BlockDevice, devices.CharDevice:
+		default:
+			// Should never happen.
+			return nil, fmt.Errorf("invalid device type for DeviceAllow: %v", rule.Type)
+		}
+
+		entry := deviceAllowEntry{
+			Perms: string(rule.Permissions),
+		}
+
+		// systemd has a fairly odd (though understandable) syntax here, and
+		// because of the OCI configuration format we have to do quite a bit of
+		// trickery to convert things:
+		//
+		//  * Concrete rules with non-wildcard major/minor numbers have to use
+		//    /dev/{block,char} paths. This is slightly odd because it means
+		//    that we cannot add whitelist rules for devices that don't exist,
+		//    but there's not too much we can do about that.
+		//
+		//    However, path globbing is not support for path-based rules so we
+		//    need to handle wildcards in some other manner.
+		//
+		//  * Wildcard-minor rules have to specify a "device group name" (the
+		//    second column in /proc/devices).
+		//
+		//  * Wildcard (major and minor) rules can just specify a glob with the
+		//    type ("char-*" or "block-*").
+		//
+		// The only type of rule we can't handle is wildcard-major rules, and
+		// so we'll give a warning in that case (note that the fallback code
+		// will insert any rules systemd couldn't handle). What amazing fun.
+
+		if rule.Major == devices.Wildcard {
+			// "_ *:n _" rules aren't supported by systemd.
+			if rule.Minor != devices.Wildcard {
+				logrus.Warnf("systemd doesn't support '*:n' device rules -- temporarily ignoring rule: %v", *rule)
+				continue
+			}
+
+			// "_ *:* _" rules just wildcard everything.
+			prefix, err := groupPrefix(rule.Type)
+			if err != nil {
+				return nil, err
+			}
+			entry.Path = prefix + "*"
+		} else if rule.Minor == devices.Wildcard {
+			// "_ n:* _" rules require a device group from /proc/devices.
+			group, err := findDeviceGroup(rule.Type, rule.Major)
+			if err != nil {
+				return nil, fmt.Errorf("unable to find device '%v/%d': %w", rule.Type, rule.Major, err)
+			}
+			if group == "" {
+				// Couldn't find a group.
+				logrus.Warnf("could not find device group for '%v/%d' in /proc/devices -- temporarily ignoring rule: %v", rule.Type, rule.Major, *rule)
+				continue
+			}
+			entry.Path = group
+		} else {
+			// "_ n:m _" rules are just a path in /dev/{block,char}/.
+			switch rule.Type {
+			case devices.BlockDevice:
+				entry.Path = fmt.Sprintf("/dev/block/%d:%d", rule.Major, rule.Minor)
+			case devices.CharDevice:
+				entry.Path = fmt.Sprintf("/dev/char/%d:%d", rule.Major, rule.Minor)
+			}
+		}
+		deviceAllowList = append(deviceAllowList, entry)
+	}
+
+	properties = append(properties, newProp("DeviceAllow", deviceAllowList))
+	return properties, nil
+}
+
+func newProp(name string, units interface{}) systemdDbus.Property {
+	return systemdDbus.Property{
+		Name:  name,
+		Value: dbus.MakeVariant(units),
+	}
+}
+
+func groupPrefix(ruleType devices.Type) (string, error) {
+	switch ruleType {
+	case devices.BlockDevice:
+		return "block-", nil
+	case devices.CharDevice:
+		return "char-", nil
+	default:
+		return "", fmt.Errorf("device type %v has no group prefix", ruleType)
+	}
+}
+
+// findDeviceGroup tries to find the device group name (as listed in
+// /proc/devices) with the type prefixed as required for DeviceAllow, for a
+// given (type, major) combination. If more than one device group exists, an
+// arbitrary one is chosen.
+func findDeviceGroup(ruleType devices.Type, ruleMajor int64) (string, error) {
+	fh, err := os.Open("/proc/devices")
+	if err != nil {
+		return "", err
+	}
+	defer fh.Close()
+
+	prefix, err := groupPrefix(ruleType)
+	if err != nil {
+		return "", err
+	}
+
+	scanner := bufio.NewScanner(fh)
+	var currentType devices.Type
+	for scanner.Scan() {
+		// We need to strip spaces because the first number is column-aligned.
+		line := strings.TrimSpace(scanner.Text())
+
+		// Handle the "header" lines.
+		switch line {
+		case "Block devices:":
+			currentType = devices.BlockDevice
+			continue
+		case "Character devices:":
+			currentType = devices.CharDevice
+			continue
+		case "":
+			continue
+		}
+
+		// Skip lines unrelated to our type.
+		if currentType != ruleType {
+			continue
+		}
+
+		// Parse out the (major, name).
+		var (
+			currMajor int64
+			currName  string
+		)
+		if n, err := fmt.Sscanf(line, "%d %s", &currMajor, &currName); err != nil || n != 2 {
+			if err == nil {
+				err = errors.New("wrong number of fields")
+			}
+			return "", fmt.Errorf("scan /proc/devices line %q: %w", line, err)
+		}
+
+		if currMajor == ruleMajor {
+			return prefix + currName, nil
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return "", fmt.Errorf("reading /proc/devices: %w", err)
+	}
+	// Couldn't find the device group.
+	return "", nil
+}
+
+// DeviceAllow is the dbus type "a(ss)" which means we need a struct
+// to represent it in Go.
+type deviceAllowEntry struct {
+	Path  string
+	Perms string
+}
+
+func allowAllDevices() []systemdDbus.Property {
+	// Setting mode to auto and removing all DeviceAllow rules
+	// results in allowing access to all devices.
+	return []systemdDbus.Property{
+		newProp("DevicePolicy", "auto"),
+		newProp("DeviceAllow", []deviceAllowEntry{}),
+	}
+}

libcontainer/cgroups/devices/systemd_test.go

@@ -0,0 +1,253 @@
+package devices
+
+import (
+	"bytes"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
+	"github.com/opencontainers/runc/libcontainer/configs"
+	"github.com/opencontainers/runc/libcontainer/devices"
+)
+
+// TestPodSkipDevicesUpdate checks that updating a pod having SkipDevices: true
+// does not result in spurious "permission denied" errors in a container
+// running under the pod. The test is somewhat similar in nature to the
+// @test "update devices [minimal transition rules]" in tests/integration,
+// but uses a pod.
+func TestPodSkipDevicesUpdate(t *testing.T) {
+	if !systemd.IsRunningSystemd() {
+		t.Skip("Test requires systemd.")
+	}
+	if os.Geteuid() != 0 {
+		t.Skip("Test requires root.")
+	}
+
+	podName := "system-runc_test_pod" + t.Name() + ".slice"
+	podConfig := &configs.Cgroup{
+		Systemd: true,
+		Parent:  "system.slice",
+		Name:    podName,
+		Resources: &configs.Resources{
+			PidsLimit:   42,
+			Memory:      32 * 1024 * 1024,
+			SkipDevices: true,
+		},
+	}
+	// Create "pod" cgroup (a systemd slice to hold containers).
+	pm := newManager(t, podConfig)
+	if err := pm.Apply(-1); err != nil {
+		t.Fatal(err)
+	}
+	if err := pm.Set(podConfig.Resources); err != nil {
+		t.Fatal(err)
+	}
+
+	containerConfig := &configs.Cgroup{
+		Parent:      podName,
+		ScopePrefix: "test",
+		Name:        "PodSkipDevicesUpdate",
+		Resources: &configs.Resources{
+			Devices: []*devices.Rule{
+				// Allow access to /dev/null.
+				{
+					Type:        devices.CharDevice,
+					Major:       1,
+					Minor:       3,
+					Permissions: "rwm",
+					Allow:       true,
+				},
+			},
+		},
+	}
+
+	// Create a "container" within the "pod" cgroup.
+	// This is not a real container, just a process in the cgroup.
+	cmd := exec.Command("bash", "-c", "while true; do echo > /dev/null; done")
+	cmd.Env = append(os.Environ(), "LANG=C")
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	if err := cmd.Start(); err != nil {
+		t.Fatal(err)
+	}
+	// Make sure to not leave a zombie.
+	defer func() {
+		// These may fail, we don't care.
+		_ = cmd.Process.Kill()
+		_ = cmd.Wait()
+	}()
+
+	// Put the process into a cgroup.
+	cm := newManager(t, containerConfig)
+	if err := cm.Apply(cmd.Process.Pid); err != nil {
+		t.Fatal(err)
+	}
+	// Check that we put the "container" into the "pod" cgroup.
+	if !strings.HasPrefix(cm.Path("devices"), pm.Path("devices")) {
+		t.Fatalf("expected container cgroup path %q to be under pod cgroup path %q",
+			cm.Path("devices"), pm.Path("devices"))
+	}
+	if err := cm.Set(containerConfig.Resources); err != nil {
+		t.Fatal(err)
+	}
+
+	// Now update the pod a few times.
+	for i := 0; i < 42; i++ {
+		podConfig.Resources.PidsLimit++
+		podConfig.Resources.Memory += 1024 * 1024
+		if err := pm.Set(podConfig.Resources); err != nil {
+			t.Fatal(err)
+		}
+	}
+	// Kill the "container".
+	if err := cmd.Process.Kill(); err != nil {
+		t.Fatal(err)
+	}
+
+	_ = cmd.Wait()
+
+	// "Container" stderr should be empty.
+	if stderr.Len() != 0 {
+		t.Fatalf("container stderr not empty: %s", stderr.String())
+	}
+}
+
+func testSkipDevices(t *testing.T, skipDevices bool, expected []string) {
+	if !systemd.IsRunningSystemd() {
+		t.Skip("Test requires systemd.")
+	}
+	if os.Geteuid() != 0 {
+		t.Skip("Test requires root.")
+	}
+
+	podConfig := &configs.Cgroup{
+		Parent: "system.slice",
+		Name:   "system-runc_test_pods.slice",
+		Resources: &configs.Resources{
+			SkipDevices: skipDevices,
+		},
+	}
+	// Create "pods" cgroup (a systemd slice to hold containers).
+	pm := newManager(t, podConfig)
+	if err := pm.Apply(-1); err != nil {
+		t.Fatal(err)
+	}
+	if err := pm.Set(podConfig.Resources); err != nil {
+		t.Fatal(err)
+	}
+
+	config := &configs.Cgroup{
+		Parent:      "system-runc_test_pods.slice",
+		ScopePrefix: "test",
+		Name:        "SkipDevices",
+		Resources: &configs.Resources{
+			Devices: []*devices.Rule{
+				// Allow access to /dev/full only.
+				{
+					Type:        devices.CharDevice,
+					Major:       1,
+					Minor:       7,
+					Permissions: "rwm",
+					Allow:       true,
+				},
+			},
+		},
+	}
+
+	// Create a "container" within the "pods" cgroup.
+	// This is not a real container, just a process in the cgroup.
+	cmd := exec.Command("bash", "-c", "read; echo > /dev/full; cat /dev/null; true")
+	cmd.Env = append(os.Environ(), "LANG=C")
+	stdinR, stdinW, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	cmd.Stdin = stdinR
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	err = cmd.Start()
+	stdinR.Close()
+	defer stdinW.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Make sure to not leave a zombie.
+	defer func() {
+		// These may fail, we don't care.
+		_, _ = stdinW.WriteString("hey\n")
+		_ = cmd.Wait()
+	}()
+
+	// Put the process into a cgroup.
+	m := newManager(t, config)
+	if err := m.Apply(cmd.Process.Pid); err != nil {
+		t.Fatal(err)
+	}
+	// Check that we put the "container" into the "pod" cgroup.
+	if !strings.HasPrefix(m.Path("devices"), pm.Path("devices")) {
+		t.Fatalf("expected container cgroup path %q to be under pod cgroup path %q",
+			m.Path("devices"), pm.Path("devices"))
+	}
+	if err := m.Set(config.Resources); err != nil {
+		// failed to write "c 1:7 rwm": write /sys/fs/cgroup/devices/system.slice/system-runc_test_pods.slice/test-SkipDevices.scope/devices.allow: operation not permitted
+		if skipDevices == false && strings.HasSuffix(err.Error(), "/devices.allow: operation not permitted") {
+			// Cgroup v1 devices controller gives EPERM on trying
+			// to enable devices that are not enabled
+			// (skipDevices=false) in a parent cgroup.
+			// If this happens, test is passing.
+			return
+		}
+		t.Fatal(err)
+	}
+
+	// Check that we can access /dev/full but not /dev/zero.
+	if _, err := stdinW.WriteString("wow\n"); err != nil {
+		t.Fatal(err)
+	}
+	if err := cmd.Wait(); err != nil {
+		t.Fatal(err)
+	}
+	for _, exp := range expected {
+		if !strings.Contains(stderr.String(), exp) {
+			t.Errorf("expected %q, got: %s", exp, stderr.String())
+		}
+	}
+}
+
+func TestSkipDevicesTrue(t *testing.T) {
+	testSkipDevices(t, true, []string{
+		"echo: write error: No space left on device",
+		"cat: /dev/null: Operation not permitted",
+	})
+}
+
+func TestSkipDevicesFalse(t *testing.T) {
+	// If SkipDevices is not set for the parent slice, access to both
+	// devices should fail. This is done to assess the test correctness.
+	// For cgroup v1, we check for m.Set returning EPERM.
+	// For cgroup v2, we check for the errors below.
+	testSkipDevices(t, false, []string{
+		"/dev/full: Operation not permitted",
+		"cat: /dev/null: Operation not permitted",
+	})
+}
+
+func newManager(t *testing.T, config *configs.Cgroup) (m cgroups.Manager) {
+	t.Helper()
+	var err error
+
+	if cgroups.IsCgroup2UnifiedMode() {
+		m, err = systemd.NewUnifiedManager(config, "")
+	} else {
+		m, err = systemd.NewLegacyManager(config, nil)
+	}
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = m.Destroy() })
+
+	return m
+}

libcontainer/cgroups/devices/v1.go

@@ -0,0 +1,84 @@
+package devices
+
+import (
+	"bytes"
+	"errors"
+	"reflect"
+
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/configs"
+	"github.com/opencontainers/runc/libcontainer/devices"
+	"github.com/opencontainers/runc/libcontainer/userns"
+)
+
+var testingSkipFinalCheck bool
+
+func setV1(path string, r *configs.Resources) error {
+	if userns.RunningInUserNS() || r.SkipDevices {
+		return nil
+	}
+	// Generate two emulators, one for the current state of the cgroup and one
+	// for the requested state by the user.
+	current, err := loadEmulator(path)
+	if err != nil {
+		return err
+	}
+	target, err := buildEmulator(r.Devices)
+	if err != nil {
+		return err
+	}
+
+	// Compute the minimal set of transition rules needed to achieve the
+	// requested state.
+	transitionRules, err := current.Transition(target)
+	if err != nil {
+		return err
+	}
+	for _, rule := range transitionRules {
+		file := "devices.deny"
+		if rule.Allow {
+			file = "devices.allow"
+		}
+		if err := cgroups.WriteFile(path, file, rule.CgroupString()); err != nil {
+			return err
+		}
+	}
+
+	// Final safety check -- ensure that the resulting state is what was
+	// requested. This is only really correct for white-lists, but for
+	// black-lists we can at least check that the cgroup is in the right mode.
+	//
+	// This safety-check is skipped for the unit tests because we cannot
+	// currently mock devices.list correctly.
+	if !testingSkipFinalCheck {
+		currentAfter, err := loadEmulator(path)
+		if err != nil {
+			return err
+		}
+		if !target.IsBlacklist() && !reflect.DeepEqual(currentAfter, target) {
+			return errors.New("resulting devices cgroup doesn't precisely match target")
+		} else if target.IsBlacklist() != currentAfter.IsBlacklist() {
+			return errors.New("resulting devices cgroup doesn't match target mode")
+		}
+	}
+	return nil
+}
+
+func loadEmulator(path string) (*Emulator, error) {
+	list, err := cgroups.ReadFile(path, "devices.list")
+	if err != nil {
+		return nil, err
+	}
+	return EmulatorFromList(bytes.NewBufferString(list))
+}
+
+func buildEmulator(rules []*devices.Rule) (*Emulator, error) {
+	// This defaults to a white-list -- which is what we want!
+	emu := &Emulator{}
+	for _, rule := range rules {
+		if err := emu.Apply(*rule); err != nil {
+			return nil, err
+		}
+	}
+	return emu, nil
+}

libcontainer/cgroups/devices/v1_test.go

@@ -1,21 +1,34 @@
-package fs
+package devices
 
 import (
+	"os"
+	"path"
 	"testing"
 
+	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/opencontainers/runc/libcontainer/devices"
 )
 
-func TestDevicesSetAllow(t *testing.T) {
-	path := tempDir(t, "devices")
+func init() {
+	testingSkipFinalCheck = true
+	cgroups.TestMode = true
+}
 
-	writeFileContents(t, path, map[string]string{
+func TestSetV1Allow(t *testing.T) {
+	dir := t.TempDir()
+
+	for file, contents := range map[string]string{
 		"devices.allow": "",
 		"devices.deny":  "",
 		"devices.list":  "a *:* rwm",
-	})
+	} {
+		err := os.WriteFile(path.Join(dir, file), []byte(contents), 0o600)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
 
 	r := &configs.Resources{
 		Devices: []*devices.Rule{
@@ -29,13 +42,12 @@ func TestDevicesSetAllow(t *testing.T) {
 		},
 	}
 
-	d := &DevicesGroup{TestingSkipFinalCheck: true}
-	if err := d.Set(path, r); err != nil {
+	if err := setV1(dir, r); err != nil {
 		t.Fatal(err)
 	}
 
 	// The default deny rule must be written.
-	value, err := fscommon.GetCgroupParamString(path, "devices.deny")
+	value, err := fscommon.GetCgroupParamString(dir, "devices.deny")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -44,7 +56,7 @@ func TestDevicesSetAllow(t *testing.T) {
 	}
 
 	// Permitted rule must be written.
-	if value, err := fscommon.GetCgroupParamString(path, "devices.allow"); err != nil {
+	if value, err := fscommon.GetCgroupParamString(dir, "devices.allow"); err != nil {
 		t.Fatal(err)
 	} else if value != "c 1:5 rwm" {
 		t.Errorf("Got the wrong value (%q), set devices.allow failed.", value)

libcontainer/cgroups/devices/v2.go

@@ -1,12 +1,10 @@
-package fs2
+package devices
 
 import (
 	"fmt"
 
 	"golang.org/x/sys/unix"
 
-	"github.com/opencontainers/runc/libcontainer/cgroups/ebpf"
-	"github.com/opencontainers/runc/libcontainer/cgroups/ebpf/devicefilter"
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/opencontainers/runc/libcontainer/devices"
 	"github.com/opencontainers/runc/libcontainer/userns"
@@ -53,11 +51,11 @@ func canSkipEBPFError(r *configs.Resources) bool {
 	return true
 }
 
-func setDevices(dirPath string, r *configs.Resources) error {
+func setV2(dirPath string, r *configs.Resources) error {
 	if r.SkipDevices {
 		return nil
 	}
-	insts, license, err := devicefilter.DeviceFilter(r.Devices)
+	insts, license, err := DeviceFilter(r.Devices)
 	if err != nil {
 		return err
 	}
@@ -66,7 +64,7 @@ func setDevices(dirPath string, r *configs.Resources) error {
 		return fmt.Errorf("cannot get dir FD for %s", dirPath)
 	}
 	defer unix.Close(dirFD)
-	if _, err := ebpf.LoadAttachCgroupDeviceFilter(insts, license, dirFD); err != nil {
+	if _, err := LoadAttachCgroupDeviceFilter(insts, license, dirFD); err != nil {
 		if !canSkipEBPFError(r) {
 			return err
 		}

libcontainer/cgroups/fs/devices.go

@@ -1,20 +1,11 @@
 package fs
 
 import (
-	"bytes"
-	"errors"
-	"reflect"
-
 	"github.com/opencontainers/runc/libcontainer/cgroups"
-	cgroupdevices "github.com/opencontainers/runc/libcontainer/cgroups/devices"
 	"github.com/opencontainers/runc/libcontainer/configs"
-	"github.com/opencontainers/runc/libcontainer/devices"
-	"github.com/opencontainers/runc/libcontainer/userns"
 )
 
-type DevicesGroup struct {
-	TestingSkipFinalCheck bool
-}
+type DevicesGroup struct{}
 
 func (s *DevicesGroup) Name() string {
 	return "devices"
@@ -33,75 +24,14 @@ func (s *DevicesGroup) Apply(path string, r *configs.Resources, pid int) error {
 	return apply(path, pid)
 }
 
-func loadEmulator(path string) (*cgroupdevices.Emulator, error) {
-	list, err := cgroups.ReadFile(path, "devices.list")
-	if err != nil {
-		return nil, err
-	}
-	return cgroupdevices.EmulatorFromList(bytes.NewBufferString(list))
-}
-
-func buildEmulator(rules []*devices.Rule) (*cgroupdevices.Emulator, error) {
-	// This defaults to a white-list -- which is what we want!
-	emu := &cgroupdevices.Emulator{}
-	for _, rule := range rules {
-		if err := emu.Apply(*rule); err != nil {
-			return nil, err
-		}
-	}
-	return emu, nil
-}
-
 func (s *DevicesGroup) Set(path string, r *configs.Resources) error {
-	if userns.RunningInUserNS() || r.SkipDevices {
-		return nil
-	}
-
-	// Generate two emulators, one for the current state of the cgroup and one
-	// for the requested state by the user.
-	current, err := loadEmulator(path)
-	if err != nil {
-		return err
-	}
-	target, err := buildEmulator(r.Devices)
-	if err != nil {
-		return err
-	}
-
-	// Compute the minimal set of transition rules needed to achieve the
-	// requested state.
-	transitionRules, err := current.Transition(target)
-	if err != nil {
-		return err
-	}
-	for _, rule := range transitionRules {
-		file := "devices.deny"
-		if rule.Allow {
-			file = "devices.allow"
-		}
-		if err := cgroups.WriteFile(path, file, rule.CgroupString()); err != nil {
-			return err
+	if cgroups.DevicesSetV1 == nil {
+		if len(r.Devices) == 0 {
+			return nil
 		}
+		return cgroups.ErrDevicesUnsupported
 	}
-
-	// Final safety check -- ensure that the resulting state is what was
-	// requested. This is only really correct for white-lists, but for
-	// black-lists we can at least check that the cgroup is in the right mode.
-	//
-	// This safety-check is skipped for the unit tests because we cannot
-	// currently mock devices.list correctly.
-	if !s.TestingSkipFinalCheck {
-		currentAfter, err := loadEmulator(path)
-		if err != nil {
-			return err
-		}
-		if !target.IsBlacklist() && !reflect.DeepEqual(currentAfter, target) {
-			return errors.New("resulting devices cgroup doesn't precisely match target")
-		} else if target.IsBlacklist() != currentAfter.IsBlacklist() {
-			return errors.New("resulting devices cgroup doesn't match target mode")
-		}
-	}
-	return nil
+	return cgroups.DevicesSetV1(path, r)
 }
 
 func (s *DevicesGroup) GetStats(path string, stats *cgroups.Stats) error {

libcontainer/cgroups/fs/fs.go

@@ -182,7 +182,7 @@ func (m *manager) Set(r *configs.Resources) error {
 		if err := sys.Set(path, r); err != nil {
 			// When rootless is true, errors from the device subsystem
 			// are ignored, as it is really not expected to work.
-			if m.cgroups.Rootless && sys.Name() == "devices" {
+			if m.cgroups.Rootless && sys.Name() == "devices" && !errors.Is(err, cgroups.ErrDevicesUnsupported) {
 				continue
 			}
 			// However, errors from other subsystems are not ignored.

libcontainer/cgroups/fs2/fs2.go

@@ -175,8 +175,10 @@ func (m *manager) Set(r *configs.Resources) error {
 	// When rootless is true, errors from the device subsystem are ignored because it is really not expected to work.
 	// However, errors from other subsystems are not ignored.
 	// see @test "runc create (rootless + limits + no cgrouppath + no permission) fails with informative error"
-	if err := setDevices(m.dirPath, r); err != nil && !m.config.Rootless {
-		return err
+	if err := setDevices(m.dirPath, r); err != nil {
+		if !m.config.Rootless || errors.Is(err, cgroups.ErrDevicesUnsupported) {
+			return err
+		}
 	}
 	// cpuset (since kernel 5.0)
 	if err := setCpuset(m.dirPath, r); err != nil {
@@ -201,6 +203,16 @@ func (m *manager) Set(r *configs.Resources) error {
 	return nil
 }
 
+func setDevices(dirPath string, r *configs.Resources) error {
+	if cgroups.DevicesSetV2 == nil {
+		if len(r.Devices) > 0 {
+			return cgroups.ErrDevicesUnsupported
+		}
+		return nil
+	}
+	return cgroups.DevicesSetV2(dirPath, r)
+}
+
 func (m *manager) setUnified(res map[string]string) error {
 	for k, v := range res {
 		if strings.Contains(k, "/") {

libcontainer/cgroups/systemd/common.go

@@ -16,6 +16,7 @@ import (
 	dbus "github.com/godbus/dbus/v5"
 	"github.com/sirupsen/logrus"
 
+	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"github.com/opencontainers/runc/libcontainer/configs"
 )
 
@@ -32,6 +33,8 @@ var (
 
 	isRunningSystemdOnce sync.Once
 	isRunningSystemd     bool
+
+	GenerateDeviceProps func(*configs.Resources) ([]systemdDbus.Property, error)
 )
 
 // NOTE: This function comes from package github.com/coreos/go-systemd/util
@@ -313,3 +316,16 @@ func addCpuset(cm *dbusConnManager, props *[]systemdDbus.Property, cpus, mems st
 	}
 	return nil
 }
+
+// generateDeviceProperties takes the configured device rules and generates a
+// corresponding set of systemd properties to configure the devices correctly.
+func generateDeviceProperties(r *configs.Resources) ([]systemdDbus.Property, error) {
+	if GenerateDeviceProps == nil {
+		if len(r.Devices) > 0 {
+			return nil, cgroups.ErrDevicesUnsupported
+		}
+		return nil, nil
+	}
+
+	return GenerateDeviceProps(r)
+}

libcontainer/cgroups/systemd/devices.go

@@ -1,20 +1,11 @@
 package systemd
 
 import (
-	"bufio"
-	"errors"
-	"fmt"
-	"os"
 	"reflect"
-	"strings"
 
-	systemdDbus "github.com/coreos/go-systemd/v22/dbus"
 	dbus "github.com/godbus/dbus/v5"
-	"github.com/sirupsen/logrus"
 
-	cgroupdevices "github.com/opencontainers/runc/libcontainer/cgroups/devices"
 	"github.com/opencontainers/runc/libcontainer/configs"
-	"github.com/opencontainers/runc/libcontainer/devices"
 )
 
 // freezeBeforeSet answers whether there is a need to freeze the cgroup before
@@ -81,213 +72,3 @@ func (m *legacyManager) freezeBeforeSet(unitName string, r *configs.Resources) (
 	}
 	return
 }
-
-func groupPrefix(ruleType devices.Type) (string, error) {
-	switch ruleType {
-	case devices.BlockDevice:
-		return "block-", nil
-	case devices.CharDevice:
-		return "char-", nil
-	default:
-		return "", fmt.Errorf("device type %v has no group prefix", ruleType)
-	}
-}
-
-// findDeviceGroup tries to find the device group name (as listed in
-// /proc/devices) with the type prefixed as required for DeviceAllow, for a
-// given (type, major) combination. If more than one device group exists, an
-// arbitrary one is chosen.
-func findDeviceGroup(ruleType devices.Type, ruleMajor int64) (string, error) {
-	fh, err := os.Open("/proc/devices")
-	if err != nil {
-		return "", err
-	}
-	defer fh.Close()
-
-	prefix, err := groupPrefix(ruleType)
-	if err != nil {
-		return "", err
-	}
-
-	scanner := bufio.NewScanner(fh)
-	var currentType devices.Type
-	for scanner.Scan() {
-		// We need to strip spaces because the first number is column-aligned.
-		line := strings.TrimSpace(scanner.Text())
-
-		// Handle the "header" lines.
-		switch line {
-		case "Block devices:":
-			currentType = devices.BlockDevice
-			continue
-		case "Character devices:":
-			currentType = devices.CharDevice
-			continue
-		case "":
-			continue
-		}
-
-		// Skip lines unrelated to our type.
-		if currentType != ruleType {
-			continue
-		}
-
-		// Parse out the (major, name).
-		var (
-			currMajor int64
-			currName  string
-		)
-		if n, err := fmt.Sscanf(line, "%d %s", &currMajor, &currName); err != nil || n != 2 {
-			if err == nil {
-				err = errors.New("wrong number of fields")
-			}
-			return "", fmt.Errorf("scan /proc/devices line %q: %w", line, err)
-		}
-
-		if currMajor == ruleMajor {
-			return prefix + currName, nil
-		}
-	}
-	if err := scanner.Err(); err != nil {
-		return "", fmt.Errorf("reading /proc/devices: %w", err)
-	}
-	// Couldn't find the device group.
-	return "", nil
-}
-
-// DeviceAllow is the dbus type "a(ss)" which means we need a struct
-// to represent it in Go.
-type deviceAllowEntry struct {
-	Path  string
-	Perms string
-}
-
-func allowAllDevices() []systemdDbus.Property {
-	// Setting mode to auto and removing all DeviceAllow rules
-	// results in allowing access to all devices.
-	return []systemdDbus.Property{
-		newProp("DevicePolicy", "auto"),
-		newProp("DeviceAllow", []deviceAllowEntry{}),
-	}
-}
-
-// generateDeviceProperties takes the configured device rules and generates a
-// corresponding set of systemd properties to configure the devices correctly.
-func generateDeviceProperties(r *configs.Resources) ([]systemdDbus.Property, error) {
-	if r.SkipDevices {
-		return nil, nil
-	}
-
-	properties := []systemdDbus.Property{
-		// Always run in the strictest white-list mode.
-		newProp("DevicePolicy", "strict"),
-		// Empty the DeviceAllow array before filling it.
-		newProp("DeviceAllow", []deviceAllowEntry{}),
-	}
-
-	// Figure out the set of rules.
-	configEmu := &cgroupdevices.Emulator{}
-	for _, rule := range r.Devices {
-		if err := configEmu.Apply(*rule); err != nil {
-			return nil, fmt.Errorf("unable to apply rule for systemd: %w", err)
-		}
-	}
-	// systemd doesn't support blacklists. So we log a warning, and tell
-	// systemd to act as a deny-all whitelist. This ruleset will be replaced
-	// with our normal fallback code. This may result in spurious errors, but
-	// the only other option is to error out here.
-	if configEmu.IsBlacklist() {
-		// However, if we're dealing with an allow-all rule then we can do it.
-		if configEmu.IsAllowAll() {
-			return allowAllDevices(), nil
-		}
-		logrus.Warn("systemd doesn't support blacklist device rules -- applying temporary deny-all rule")
-		return properties, nil
-	}
-
-	// Now generate the set of rules we actually need to apply. Unlike the
-	// normal devices cgroup, in "strict" mode systemd defaults to a deny-all
-	// whitelist which is the default for devices.Emulator.
-	finalRules, err := configEmu.Rules()
-	if err != nil {
-		return nil, fmt.Errorf("unable to get simplified rules for systemd: %w", err)
-	}
-	var deviceAllowList []deviceAllowEntry
-	for _, rule := range finalRules {
-		if !rule.Allow {
-			// Should never happen.
-			return nil, fmt.Errorf("[internal error] cannot add deny rule to systemd DeviceAllow list: %v", *rule)
-		}
-		switch rule.Type {
-		case devices.BlockDevice, devices.CharDevice:
-		default:
-			// Should never happen.
-			return nil, fmt.Errorf("invalid device type for DeviceAllow: %v", rule.Type)
-		}
-
-		entry := deviceAllowEntry{
-			Perms: string(rule.Permissions),
-		}
-
-		// systemd has a fairly odd (though understandable) syntax here, and
-		// because of the OCI configuration format we have to do quite a bit of
-		// trickery to convert things:
-		//
-		//  * Concrete rules with non-wildcard major/minor numbers have to use
-		//    /dev/{block,char} paths. This is slightly odd because it means
-		//    that we cannot add whitelist rules for devices that don't exist,
-		//    but there's not too much we can do about that.
-		//
-		//    However, path globbing is not support for path-based rules so we
-		//    need to handle wildcards in some other manner.
-		//
-		//  * Wildcard-minor rules have to specify a "device group name" (the
-		//    second column in /proc/devices).
-		//
-		//  * Wildcard (major and minor) rules can just specify a glob with the
-		//    type ("char-*" or "block-*").
-		//
-		// The only type of rule we can't handle is wildcard-major rules, and
-		// so we'll give a warning in that case (note that the fallback code
-		// will insert any rules systemd couldn't handle). What amazing fun.
-
-		if rule.Major == devices.Wildcard {
-			// "_ *:n _" rules aren't supported by systemd.
-			if rule.Minor != devices.Wildcard {
-				logrus.Warnf("systemd doesn't support '*:n' device rules -- temporarily ignoring rule: %v", *rule)
-				continue
-			}
-
-			// "_ *:* _" rules just wildcard everything.
-			prefix, err := groupPrefix(rule.Type)
-			if err != nil {
-				return nil, err
-			}
-			entry.Path = prefix + "*"
-		} else if rule.Minor == devices.Wildcard {
-			// "_ n:* _" rules require a device group from /proc/devices.
-			group, err := findDeviceGroup(rule.Type, rule.Major)
-			if err != nil {
-				return nil, fmt.Errorf("unable to find device '%v/%d': %w", rule.Type, rule.Major, err)
-			}
-			if group == "" {
-				// Couldn't find a group.
-				logrus.Warnf("could not find device group for '%v/%d' in /proc/devices -- temporarily ignoring rule: %v", rule.Type, rule.Major, *rule)
-				continue
-			}
-			entry.Path = group
-		} else {
-			// "_ n:m _" rules are just a path in /dev/{block,char}/.
-			switch rule.Type {
-			case devices.BlockDevice:
-				entry.Path = fmt.Sprintf("/dev/block/%d:%d", rule.Major, rule.Minor)
-			case devices.CharDevice:
-				entry.Path = fmt.Sprintf("/dev/char/%d:%d", rule.Major, rule.Minor)
-			}
-		}
-		deviceAllowList = append(deviceAllowList, entry)
-	}
-
-	properties = append(properties, newProp("DeviceAllow", deviceAllowList))
-	return properties, nil
-}

libcontainer/cgroups/systemd/freeze_test.go

@@ -8,235 +8,11 @@ import (
 	"strings"
 	"testing"
 
-	"golang.org/x/sys/unix"
-
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"github.com/opencontainers/runc/libcontainer/configs"
-	"github.com/opencontainers/runc/libcontainer/devices"
+	"golang.org/x/sys/unix"
 )
 
-// TestPodSkipDevicesUpdate checks that updating a pod having SkipDevices: true
-// does not result in spurious "permission denied" errors in a container
-// running under the pod. The test is somewhat similar in nature to the
-// @test "update devices [minimal transition rules]" in tests/integration,
-// but uses a pod.
-func TestPodSkipDevicesUpdate(t *testing.T) {
-	if !IsRunningSystemd() {
-		t.Skip("Test requires systemd.")
-	}
-	if os.Geteuid() != 0 {
-		t.Skip("Test requires root.")
-	}
-
-	podName := "system-runc_test_pod" + t.Name() + ".slice"
-	podConfig := &configs.Cgroup{
-		Systemd: true,
-		Parent:  "system.slice",
-		Name:    podName,
-		Resources: &configs.Resources{
-			PidsLimit:   42,
-			Memory:      32 * 1024 * 1024,
-			SkipDevices: true,
-		},
-	}
-	// Create "pod" cgroup (a systemd slice to hold containers).
-	pm := newManager(t, podConfig)
-	if err := pm.Apply(-1); err != nil {
-		t.Fatal(err)
-	}
-	if err := pm.Set(podConfig.Resources); err != nil {
-		t.Fatal(err)
-	}
-
-	containerConfig := &configs.Cgroup{
-		Parent:      podName,
-		ScopePrefix: "test",
-		Name:        "PodSkipDevicesUpdate",
-		Resources: &configs.Resources{
-			Devices: []*devices.Rule{
-				// Allow access to /dev/null.
-				{
-					Type:        devices.CharDevice,
-					Major:       1,
-					Minor:       3,
-					Permissions: "rwm",
-					Allow:       true,
-				},
-			},
-		},
-	}
-
-	// Create a "container" within the "pod" cgroup.
-	// This is not a real container, just a process in the cgroup.
-	cmd := exec.Command("bash", "-c", "while true; do echo > /dev/null; done")
-	cmd.Env = append(os.Environ(), "LANG=C")
-	var stderr bytes.Buffer
-	cmd.Stderr = &stderr
-	if err := cmd.Start(); err != nil {
-		t.Fatal(err)
-	}
-	// Make sure to not leave a zombie.
-	defer func() {
-		// These may fail, we don't care.
-		_ = cmd.Process.Kill()
-		_ = cmd.Wait()
-	}()
-
-	// Put the process into a cgroup.
-	cm := newManager(t, containerConfig)
-	if err := cm.Apply(cmd.Process.Pid); err != nil {
-		t.Fatal(err)
-	}
-	// Check that we put the "container" into the "pod" cgroup.
-	if !strings.HasPrefix(cm.Path("devices"), pm.Path("devices")) {
-		t.Fatalf("expected container cgroup path %q to be under pod cgroup path %q",
-			cm.Path("devices"), pm.Path("devices"))
-	}
-	if err := cm.Set(containerConfig.Resources); err != nil {
-		t.Fatal(err)
-	}
-
-	// Now update the pod a few times.
-	for i := 0; i < 42; i++ {
-		podConfig.Resources.PidsLimit++
-		podConfig.Resources.Memory += 1024 * 1024
-		if err := pm.Set(podConfig.Resources); err != nil {
-			t.Fatal(err)
-		}
-	}
-	// Kill the "container".
-	if err := cmd.Process.Kill(); err != nil {
-		t.Fatal(err)
-	}
-
-	_ = cmd.Wait()
-
-	// "Container" stderr should be empty.
-	if stderr.Len() != 0 {
-		t.Fatalf("container stderr not empty: %s", stderr.String())
-	}
-}
-
-func testSkipDevices(t *testing.T, skipDevices bool, expected []string) {
-	if !IsRunningSystemd() {
-		t.Skip("Test requires systemd.")
-	}
-	if os.Geteuid() != 0 {
-		t.Skip("Test requires root.")
-	}
-
-	podConfig := &configs.Cgroup{
-		Parent: "system.slice",
-		Name:   "system-runc_test_pods.slice",
-		Resources: &configs.Resources{
-			SkipDevices: skipDevices,
-		},
-	}
-	// Create "pods" cgroup (a systemd slice to hold containers).
-	pm := newManager(t, podConfig)
-	if err := pm.Apply(-1); err != nil {
-		t.Fatal(err)
-	}
-	if err := pm.Set(podConfig.Resources); err != nil {
-		t.Fatal(err)
-	}
-
-	config := &configs.Cgroup{
-		Parent:      "system-runc_test_pods.slice",
-		ScopePrefix: "test",
-		Name:        "SkipDevices",
-		Resources: &configs.Resources{
-			Devices: []*devices.Rule{
-				// Allow access to /dev/full only.
-				{
-					Type:        devices.CharDevice,
-					Major:       1,
-					Minor:       7,
-					Permissions: "rwm",
-					Allow:       true,
-				},
-			},
-		},
-	}
-
-	// Create a "container" within the "pods" cgroup.
-	// This is not a real container, just a process in the cgroup.
-	cmd := exec.Command("bash", "-c", "read; echo > /dev/full; cat /dev/null; true")
-	cmd.Env = append(os.Environ(), "LANG=C")
-	stdinR, stdinW, err := os.Pipe()
-	if err != nil {
-		t.Fatal(err)
-	}
-	cmd.Stdin = stdinR
-	var stderr bytes.Buffer
-	cmd.Stderr = &stderr
-	err = cmd.Start()
-	stdinR.Close()
-	defer stdinW.Close()
-	if err != nil {
-		t.Fatal(err)
-	}
-	// Make sure to not leave a zombie.
-	defer func() {
-		// These may fail, we don't care.
-		_, _ = stdinW.WriteString("hey\n")
-		_ = cmd.Wait()
-	}()
-
-	// Put the process into a cgroup.
-	m := newManager(t, config)
-	if err := m.Apply(cmd.Process.Pid); err != nil {
-		t.Fatal(err)
-	}
-	// Check that we put the "container" into the "pod" cgroup.
-	if !strings.HasPrefix(m.Path("devices"), pm.Path("devices")) {
-		t.Fatalf("expected container cgroup path %q to be under pod cgroup path %q",
-			m.Path("devices"), pm.Path("devices"))
-	}
-	if err := m.Set(config.Resources); err != nil {
-		// failed to write "c 1:7 rwm": write /sys/fs/cgroup/devices/system.slice/system-runc_test_pods.slice/test-SkipDevices.scope/devices.allow: operation not permitted
-		if skipDevices == false && strings.HasSuffix(err.Error(), "/devices.allow: operation not permitted") {
-			// Cgroup v1 devices controller gives EPERM on trying
-			// to enable devices that are not enabled
-			// (skipDevices=false) in a parent cgroup.
-			// If this happens, test is passing.
-			return
-		}
-		t.Fatal(err)
-	}
-
-	// Check that we can access /dev/full but not /dev/zero.
-	if _, err := stdinW.WriteString("wow\n"); err != nil {
-		t.Fatal(err)
-	}
-	if err := cmd.Wait(); err != nil {
-		t.Fatal(err)
-	}
-	for _, exp := range expected {
-		if !strings.Contains(stderr.String(), exp) {
-			t.Errorf("expected %q, got: %s", exp, stderr.String())
-		}
-	}
-}
-
-func TestSkipDevicesTrue(t *testing.T) {
-	testSkipDevices(t, true, []string{
-		"echo: write error: No space left on device",
-		"cat: /dev/null: Operation not permitted",
-	})
-}
-
-func TestSkipDevicesFalse(t *testing.T) {
-	// If SkipDevices is not set for the parent slice, access to both
-	// devices should fail. This is done to assess the test correctness.
-	// For cgroup v1, we check for m.Set returning EPERM.
-	// For cgroup v2, we check for the errors below.
-	testSkipDevices(t, false, []string{
-		"/dev/full: Operation not permitted",
-		"cat: /dev/null: Operation not permitted",
-	})
-}
-
 func TestFreezeBeforeSet(t *testing.T) {
 	requireV1(t)
 

libcontainer/factory_linux.go

@@ -12,6 +12,8 @@ import (
 	securejoin "github.com/cyphar/filepath-securejoin"
 	"golang.org/x/sys/unix"
 
+	//nolint:revive // Enable cgroup manager to manage devices
+	_ "github.com/opencontainers/runc/libcontainer/cgroups/devices"
 	"github.com/opencontainers/runc/libcontainer/cgroups/manager"
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/opencontainers/runc/libcontainer/configs/validate"

libcontainer/integration/init_test.go

@@ -6,6 +6,8 @@ import (
 	"testing"
 
 	"github.com/opencontainers/runc/libcontainer"
+	//nolint:revive // Enable cgroup manager to manage devices
+	_ "github.com/opencontainers/runc/libcontainer/cgroups/devices"
 	_ "github.com/opencontainers/runc/libcontainer/nsenter"
 
 	"github.com/sirupsen/logrus"