check nil for selinuxLabel

Signed-off-by: Lifubang <[email protected]>

exec.go

@@ -224,5 +224,5 @@ func getProcess(context *cli.Context, bundle string) (*specs.Process, error) {
 		}
 		p.User.AdditionalGids = append(p.User.AdditionalGids, uint32(gid))
 	}
-	return p, nil
+	return p, validateProcessSpec(p)
 }

libcontainer/setns_init_linux.go

@@ -34,10 +34,12 @@ func (l *linuxSetnsInit) Init() error {
 	defer runtime.UnlockOSThread()
 
 	if !l.config.Config.NoNewKeyring {
-		if err := label.SetKeyLabel(l.config.ProcessLabel); err != nil {
-			return err
+		if l.config.ProcessLabel != "" {
+			if err := label.SetKeyLabel(l.config.ProcessLabel); err != nil {
+				return err
+			}
+			defer label.SetKeyLabel("")
 		}
-		defer label.SetKeyLabel("")
 		// Do not inherit the parent's session keyring.
 		if _, err := keys.JoinSessionKeyring(l.getSessionRingName()); err != nil {
 			// Same justification as in standart_init_linux.go as to why we
@@ -62,10 +64,12 @@ func (l *linuxSetnsInit) Init() error {
 			return err
 		}
 	}
-	if err := label.SetProcessLabel(l.config.ProcessLabel); err != nil {
-		return err
+	if l.config.ProcessLabel != "" {
+		if err := label.SetProcessLabel(l.config.ProcessLabel); err != nil {
+			return err
+		}
+		defer label.SetProcessLabel("")
 	}
-	defer label.SetProcessLabel("")
 	// Without NoNewPrivileges seccomp is a privileged operation, so we need to
 	// do this before dropping capabilities; otherwise do it as late as possible
 	// just before execve so as few syscalls take place after it as possible.

libcontainer/standard_init_linux.go

@@ -48,10 +48,12 @@ func (l *linuxStandardInit) Init() error {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 	if !l.config.Config.NoNewKeyring {
-		if err := label.SetKeyLabel(l.config.ProcessLabel); err != nil {
-			return err
+		if l.config.ProcessLabel != "" {
+			if err := label.SetKeyLabel(l.config.ProcessLabel); err != nil {
+				return err
+			}
+			defer label.SetKeyLabel("")
 		}
-		defer label.SetKeyLabel("")
 		ringname, keepperms, newperms := l.getSessionRingParams()
 
 		// Do not inherit the parent's session keyring.
@@ -146,10 +148,12 @@ func (l *linuxStandardInit) Init() error {
 	if err := syncParentReady(l.pipe); err != nil {
 		return errors.Wrap(err, "sync ready")
 	}
-	if err := label.SetProcessLabel(l.config.ProcessLabel); err != nil {
-		return errors.Wrap(err, "set process label")
+	if l.config.ProcessLabel != "" {
+		if err := label.SetProcessLabel(l.config.ProcessLabel); err != nil {
+			return errors.Wrap(err, "set process label")
+		}
+		defer label.SetProcessLabel("")
 	}
-	defer label.SetProcessLabel("")
 	// Without NoNewPrivileges seccomp is a privileged operation, so we need to
 	// do this before dropping capabilities; otherwise do it as late as possible
 	// just before execve so as few syscalls take place after it as possible.

utils_linux.go

@@ -17,6 +17,7 @@ import (
 	"github.com/opencontainers/runc/libcontainer/specconv"
 	"github.com/opencontainers/runc/libcontainer/utils"
 	"github.com/opencontainers/runtime-spec/specs-go"
+	selinux "github.com/opencontainers/selinux/go-selinux"
 
 	"github.com/coreos/go-systemd/activation"
 	"github.com/pkg/errors"
@@ -387,6 +388,9 @@ func validateProcessSpec(spec *specs.Process) error {
 	if len(spec.Args) == 0 {
 		return fmt.Errorf("args must not be empty")
 	}
+	if spec.SelinuxLabel != "" && !selinux.GetEnabled() {
+		return fmt.Errorf("selinux label is specified in config, but selinux is disabled or not supported")
+	}
 	return nil
 }