Internal change.

PiperOrigin-RevId: 361689477

runsc/cmd/gofer.go

@@ -165,7 +165,8 @@ func (g *Gofer) Execute(_ context.Context, f *flag.FlagSet, args ...interface{})
 	// Start with root mount, then add any other additional mount as needed.
 	ats := make([]p9.Attacher, 0, len(spec.Mounts)+1)
 	ap, err := fsgofer.NewAttachPoint("/", fsgofer.Config{
-		ROMount: spec.Root.Readonly || conf.Overlay,
+		ROMount:     spec.Root.Readonly || conf.Overlay,
+		EnableXattr: conf.Verity,
 	})
 	if err != nil {
 		Fatalf("creating attach point: %v", err)
@@ -177,8 +178,9 @@ func (g *Gofer) Execute(_ context.Context, f *flag.FlagSet, args ...interface{})
 	for _, m := range spec.Mounts {
 		if specutils.Is9PMount(m) {
 			cfg := fsgofer.Config{
-				ROMount: isReadonlyMount(m.Options) || conf.Overlay,
-				HostUDS: conf.FSGoferHostUDS,
+				ROMount:     isReadonlyMount(m.Options) || conf.Overlay,
+				HostUDS:     conf.FSGoferHostUDS,
+				EnableXattr: conf.Verity,
 			}
 			ap, err := fsgofer.NewAttachPoint(m.Destination, cfg)
 			if err != nil {

runsc/config/config.go

@@ -64,6 +64,9 @@ type Config struct {
 	// Overlay is whether to wrap the root filesystem in an overlay.
 	Overlay bool `flag:"overlay"`
 
+	// Verity is whether there's one or more verity file system to mount.
+	Verity bool `flag:"verity"`
+
 	// FSGoferHostUDS enables the gofer to mount a host UDS.
 	FSGoferHostUDS bool `flag:"fsgofer-host-uds"`
 

runsc/config/flags.go

@@ -69,6 +69,7 @@ func RegisterFlags() {
 		// Flags that control sandbox runtime behavior: FS related.
 		flag.Var(fileAccessTypePtr(FileAccessExclusive), "file-access", "specifies which filesystem to use for the root mount: exclusive (default), shared. Volume mounts are always shared.")
 		flag.Bool("overlay", false, "wrap filesystem mounts with writable overlay. All modifications are stored in memory inside the sandbox.")
+		flag.Bool("verity", false, "specifies whether a verity file system will be mounted.")
 		flag.Bool("overlayfs-stale-read", true, "assume root mount is an overlay filesystem")
 		flag.Bool("fsgofer-host-uds", false, "allow the gofer to mount Unix Domain Sockets.")
 		flag.Bool("vfs2", false, "enables VFSv2. This uses the new VFS layer that is faster than the previous one.")

runsc/fsgofer/fsgofer.go

@@ -66,6 +66,9 @@ type Config struct {
 
 	// HostUDS signals whether the gofer can mount a host's UDS.
 	HostUDS bool
+
+	// enableXattr allows Get/SetXattr for the mounted file systems.
+	EnableXattr bool
 }
 
 type attachPoint struct {
@@ -795,12 +798,22 @@ func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
 	return err
 }
 
-func (*localFile) GetXattr(string, uint64) (string, error) {
-	return "", unix.EOPNOTSUPP
+func (l *localFile) GetXattr(name string, size uint64) (string, error) {
+	if !l.attachPoint.conf.EnableXattr {
+		return "", unix.EOPNOTSUPP
+	}
+	buffer := make([]byte, size)
+	if _, err := unix.Fgetxattr(l.file.FD(), name, buffer); err != nil {
+		return "", err
+	}
+	return string(buffer), nil
 }
 
-func (*localFile) SetXattr(string, string, uint32) error {
-	return unix.EOPNOTSUPP
+func (l *localFile) SetXattr(name string, value string, flags uint32) error {
+	if !l.attachPoint.conf.EnableXattr {
+		return unix.EOPNOTSUPP
+	}
+	return unix.Fsetxattr(l.file.FD(), name, []byte(value), int(flags))
 }
 
 func (*localFile) ListXattr(uint64) (map[string]struct{}, error) {

runsc/fsgofer/fsgofer_test.go

@@ -565,6 +565,38 @@ func TestSetAttrOwner(t *testing.T) {
 	})
 }
 
+func SetGetXattr(l *localFile, name string, value string) error {
+	if err := l.SetXattr(name, value, 0 /* flags */); err != nil {
+		return err
+	}
+	ret, err := l.GetXattr(name, uint64(len(value)))
+	if err != nil {
+		return err
+	}
+	if ret != value {
+		return fmt.Errorf("Got value %s, want %s", ret, value)
+	}
+	return nil
+}
+
+func TestSetGetXattr(t *testing.T) {
+	xattrConfs := []Config{{ROMount: false, EnableXattr: false}, {ROMount: false, EnableXattr: true}}
+	runCustom(t, []uint32{unix.S_IFREG}, xattrConfs, func(t *testing.T, s state) {
+		name := "user.test"
+		value := "tmp"
+		err := SetGetXattr(s.file, name, value)
+		if s.conf.EnableXattr {
+			if err != nil {
+				t.Fatalf("%v: SetGetXattr failed, err: %v", s, err)
+			}
+		} else {
+			if err == nil {
+				t.Fatalf("%v: SetGetXattr should have failed", s)
+			}
+		}
+	})
+}
+
 func TestLink(t *testing.T) {
 	if !specutils.HasCapabilities(capability.CAP_DAC_READ_SEARCH) {
 		t.Skipf("Link test requires CAP_DAC_READ_SEARCH, running as %d", os.Getuid())