Relabel BTRFS Content on container Creation

This change will allow us to run SELinux in a container with
BTRFS back end.  We continue to work on fixing the kernel/BTRFS
but this change will allow SELinux Security separation on BTRFS.

It basically relabels the content on container creation.

Just relabling -init directory in BTRFS use case. Everything looks like it
works. I don't believe tar/achive stores the SELinux labels, so we are good
as far as docker commit.

Tested Speed on startup with BTRFS on top of loopback directory. BTRFS
not on loopback should get even better perfomance on startup time.  The
more inodes inside of the container image will increase the relabel time.

This patch will give people who care more about security the option of
runnin BTRFS with SELinux.  Those who don't want to take the slow down
can disable SELinux either in individual containers or for all containers
by continuing to disable SELinux in the daemon.

Without relabel:

> time docker run --security-opt label:disable fedora echo test
test

real    0m0.918s
user    0m0.009s
sys    0m0.026s

With Relabel

test

real    0m1.942s
user    0m0.007s
sys    0m0.030s

Signed-off-by: Dan Walsh <[email protected]>

Signed-off-by: Dan Walsh <[email protected]>

daemon/create.go

@@ -87,6 +87,12 @@ func (daemon *Daemon) create(params *ContainerCreateConfig) (retC *Container, re
 	if err := daemon.Register(container); err != nil {
 		return nil, err
 	}
+	container.Lock()
+	if err := parseSecurityOpt(container, params.HostConfig); err != nil {
+		container.Unlock()
+		return nil, err
+	}
+	container.Unlock()
 	if err := daemon.createRootfs(container); err != nil {
 		return nil, err
 	}

daemon/daemon.go

@@ -991,7 +991,8 @@ func (daemon *Daemon) createRootfs(container *Container) error {
 		return err
 	}
 	initID := fmt.Sprintf("%s-init", container.ID)
-	if err := daemon.driver.Create(initID, container.ImageID); err != nil {
+
+	if err := daemon.driver.Create(initID, container.ImageID, container.getMountLabel()); err != nil {
 		return err
 	}
 	initPath, err := daemon.driver.Get(initID, "")
@@ -1012,7 +1013,7 @@ func (daemon *Daemon) createRootfs(container *Container) error {
 		return err
 	}
 
-	if err := daemon.driver.Create(container.ID, initID); err != nil {
+	if err := daemon.driver.Create(container.ID, initID, ""); err != nil {
 		return err
 	}
 	return nil
@@ -1187,12 +1188,6 @@ func tempDir(rootDir string, rootUID, rootGID int) (string, error) {
 }
 
 func (daemon *Daemon) setHostConfig(container *Container, hostConfig *runconfig.HostConfig) error {
-	container.Lock()
-	if err := parseSecurityOpt(container, hostConfig); err != nil {
-		container.Unlock()
-		return err
-	}
-	container.Unlock()
 
 	// Do not lock while creating volumes since this could be calling out to external plugins
 	// Don't want to block other actions, like `docker ps` because we're waiting on an external plugin

daemon/daemon_unix.go

@@ -259,8 +259,8 @@ func checkSystem() error {
 func configureKernelSecuritySupport(config *Config, driverName string) error {
 	if config.EnableSelinuxSupport {
 		if selinuxEnabled() {
-			// As Docker on either btrfs or overlayFS and SELinux are incompatible at present, error on both being enabled
-			if driverName == "btrfs" || driverName == "overlay" {
+			// As Docker on overlayFS and SELinux are incompatible at present, error on overlayfs being enabled
+			if driverName == "overlay" {
 				return fmt.Errorf("SELinux is not supported with the %s graph driver", driverName)
 			}
 			logrus.Debug("SELinux enabled successfully")

daemon/graphdriver/aufs/aufs.go

@@ -201,7 +201,7 @@ func (a *Driver) Exists(id string) bool {
 
 // Create three folders for each id
 // mnt, layers, and diff
-func (a *Driver) Create(id, parent string) error {
+func (a *Driver) Create(id, parent, mountLabel string) error {
 	if err := a.createDirsFor(id); err != nil {
 		return err
 	}

daemon/graphdriver/aufs/aufs_test.go

@@ -99,7 +99,7 @@ func TestCreateNewDir(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 }
@@ -108,7 +108,7 @@ func TestCreateNewDirStructure(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -129,7 +129,7 @@ func TestRemoveImage(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -154,7 +154,7 @@ func TestGetWithoutParent(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -181,7 +181,7 @@ func TestCleanupWithDir(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -194,7 +194,7 @@ func TestMountedFalseResponse(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -213,10 +213,10 @@ func TestMountedTrueReponse(t *testing.T) {
 	defer os.RemoveAll(tmp)
 	defer d.Cleanup()
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
-	if err := d.Create("2", "1"); err != nil {
+	if err := d.Create("2", "1", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -239,10 +239,10 @@ func TestMountWithParent(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
-	if err := d.Create("2", "1"); err != nil {
+	if err := d.Create("2", "1", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -270,10 +270,10 @@ func TestRemoveMountedDir(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
-	if err := d.Create("2", "1"); err != nil {
+	if err := d.Create("2", "1", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -309,7 +309,7 @@ func TestCreateWithInvalidParent(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", "docker"); err == nil {
+	if err := d.Create("1", "docker", ""); err == nil {
 		t.Fatalf("Error should not be nil with parent does not exist")
 	}
 }
@@ -318,7 +318,7 @@ func TestGetDiff(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -352,10 +352,10 @@ func TestChanges(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
-	if err := d.Create("2", "1"); err != nil {
+	if err := d.Create("2", "1", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -401,7 +401,7 @@ func TestChanges(t *testing.T) {
 		t.Fatalf("Change kind should be ChangeAdd got %s", change.Kind)
 	}
 
-	if err := d.Create("3", "2"); err != nil {
+	if err := d.Create("3", "2", ""); err != nil {
 		t.Fatal(err)
 	}
 	mntPoint, err = d.Get("3", "")
@@ -446,7 +446,7 @@ func TestDiffSize(t *testing.T) {
 	d := newDriver(t)
 	defer os.RemoveAll(tmp)
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -488,7 +488,7 @@ func TestChildDiffSize(t *testing.T) {
 	defer os.RemoveAll(tmp)
 	defer d.Cleanup()
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -524,7 +524,7 @@ func TestChildDiffSize(t *testing.T) {
 		t.Fatalf("Expected size to be %d got %d", size, diffSize)
 	}
 
-	if err := d.Create("2", "1"); err != nil {
+	if err := d.Create("2", "1", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -543,7 +543,7 @@ func TestExists(t *testing.T) {
 	defer os.RemoveAll(tmp)
 	defer d.Cleanup()
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -561,7 +561,7 @@ func TestStatus(t *testing.T) {
 	defer os.RemoveAll(tmp)
 	defer d.Cleanup()
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -590,7 +590,7 @@ func TestApplyDiff(t *testing.T) {
 	defer os.RemoveAll(tmp)
 	defer d.Cleanup()
 
-	if err := d.Create("1", ""); err != nil {
+	if err := d.Create("1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -616,10 +616,10 @@ func TestApplyDiff(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := d.Create("2", ""); err != nil {
+	if err := d.Create("2", "", ""); err != nil {
 		t.Fatal(err)
 	}
-	if err := d.Create("3", "2"); err != nil {
+	if err := d.Create("3", "2", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -647,7 +647,7 @@ func TestHardlinks(t *testing.T) {
 	origFile := "test_file"
 	linkedFile := "linked_file"
 
-	if err := d.Create("source-1", ""); err != nil {
+	if err := d.Create("source-1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -667,7 +667,7 @@ func TestHardlinks(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := d.Create("source-2", "source-1"); err != nil {
+	if err := d.Create("source-2", "source-1", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -685,15 +685,15 @@ func TestHardlinks(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := d.Create("target-1", ""); err != nil {
+	if err := d.Create("target-1", "", ""); err != nil {
 		t.Fatal(err)
 	}
 
 	if _, err := d.ApplyDiff("target-1", "", layerTar1); err != nil {
 		t.Fatal(err)
 	}
 
-	if err := d.Create("target-2", "target-1"); err != nil {
+	if err := d.Create("target-2", "target-1", ""); err != nil {
 		t.Fatal(err)
 	}
 
@@ -751,7 +751,7 @@ func testMountMoreThan42Layers(t *testing.T, mountPath string) {
 		}
 		current = hash(current)
 
-		if err := d.Create(current, parent); err != nil {
+		if err := d.Create(current, parent, ""); err != nil {
 			t.Logf("Current layer %d", i)
 			t.Error(err)
 		}

daemon/graphdriver/aufs/migrate.go

@@ -86,7 +86,7 @@ func (a *Driver) migrateContainers(pth string, setupInit func(p string, rootUID,
 				}
 
 				initID := fmt.Sprintf("%s-init", id)
-				if err := a.Create(initID, metadata.Image); err != nil {
+				if err := a.Create(initID, metadata.Image, ""); err != nil {
 					return err
 				}
 
@@ -99,7 +99,7 @@ func (a *Driver) migrateContainers(pth string, setupInit func(p string, rootUID,
 					return err
 				}
 
-				if err := a.Create(id, initID); err != nil {
+				if err := a.Create(id, initID, ""); err != nil {
 					return err
 				}
 			}
@@ -153,7 +153,7 @@ func (a *Driver) migrateImage(m *metadata, pth string, migrated map[string]bool)
 			return err
 		}
 		if !a.Exists(m.ID) {
-			if err := a.Create(m.ID, m.ParentID); err != nil {
+			if err := a.Create(m.ID, m.ParentID, ""); err != nil {
 				return err
 			}
 		}

daemon/graphdriver/btrfs/btrfs.go

@@ -21,6 +21,7 @@ import (
 	"github.com/docker/docker/daemon/graphdriver"
 	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/mount"
+	"github.com/opencontainers/runc/libcontainer/label"
 )
 
 func init() {
@@ -233,7 +234,7 @@ func (d *Driver) subvolumesDirID(id string) string {
 }
 
 // Create the filesystem with given id.
-func (d *Driver) Create(id string, parent string) error {
+func (d *Driver) Create(id, parent, mountLabel string) error {
 	subvolumes := path.Join(d.home, "subvolumes")
 	rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
 	if err != nil {
@@ -255,7 +256,8 @@ func (d *Driver) Create(id string, parent string) error {
 			return err
 		}
 	}
-	return nil
+
+	return label.Relabel(path.Join(subvolumes, id), mountLabel, false)
 }
 
 // Remove the filesystem with given id.

daemon/graphdriver/devmapper/driver.go

@@ -133,7 +133,7 @@ func (d *Driver) Cleanup() error {
 }
 
 // Create adds a device with a given id and the parent.
-func (d *Driver) Create(id, parent string) error {
+func (d *Driver) Create(id, parent, mountLabel string) error {
 	if err := d.DeviceSet.AddDevice(id, parent); err != nil {
 		return err
 	}

daemon/graphdriver/driver.go

@@ -48,8 +48,8 @@ type ProtoDriver interface {
 	// String returns a string representation of this driver.
 	String() string
 	// Create creates a new, empty, filesystem layer with the
-	// specified id and parent. Parent may be "".
-	Create(id, parent string) error
+	// specified id and parent and mountLabel. Parent and mountLabel may be "".
+	Create(id, parent, mountLabel string) error
 	// Remove attempts to remove the filesystem layer with this id.
 	Remove(id string) error
 	// Get returns the mountpoint for the layered filesystem referred