Add new field to libpod to indicate whether or not to use labelling

Also update some missing fields libpod.conf obtions in man pages.

Fix sort order of security options and add a note about disabling
labeling.

When a process requests a new label.  libpod needs to reserve all
labels to make sure that their are no conflicts.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

Closes: #1406
Approved by: mheon

4 files changed, 63 insertions, 6 deletions

diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index f9e161cb3..b77beaf64 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -98,6 +98,28 @@ func (c *Container) generateSpec(ctx context.Context) (*spec.Spec, error) {
 		}
 	}
 
+	// Check if the spec file mounts contain the label Relabel flags z or Z.
+	// If they do, relabel the source directory and then remove the option.
+	for _, m := range g.Mounts() {
+		var options []string
+		for _, o := range m.Options {
+			switch o {
+			case "z":
+				fallthrough
+			case "Z":
+				if err := label.Relabel(m.Source, c.MountLabel(), label.IsShared(o)); err != nil {
+					return nil, errors.Wrapf(err, "relabel failed %q", m.Source)
+				}
+
+			default:
+				options = append(options, o)
+			}
+		}
+		m.Options = options
+	}
+
+	g.SetProcessSelinuxLabel(c.ProcessLabel())
+	g.SetLinuxMountLabel(c.MountLabel())
 	// Remove the default /dev/shm mount to ensure we overwrite it
 	g.RemoveMount("/dev/shm")
 
diff --git a/libpod/options.go b/libpod/options.go
index 1a29c0705..977f3f4c2 100644
--- a/libpod/options.go
+++ b/libpod/options.go
@@ -373,15 +373,17 @@ func WithPrivileged(privileged bool) CtrCreateOption {
 	}
 }
 
-// WithSELinuxLabels sets the mount label for SELinux.
-func WithSELinuxLabels(processLabel, mountLabel string) CtrCreateOption {
+// WithSecLabels sets the labels for SELinux.
+func WithSecLabels(labelOpts []string) CtrCreateOption {
 	return func(ctr *Container) error {
 		if ctr.valid {
 			return ErrCtrFinalized
 		}
-
-		ctr.config.ProcessLabel = processLabel
-		ctr.config.MountLabel = mountLabel
+		var err error
+		ctr.config.ProcessLabel, ctr.config.MountLabel, err = ctr.runtime.initLabels(labelOpts)
+		if err != nil {
+			return errors.Wrapf(err, "failed to init labels")
+		}
 		return nil
 	}
 }
diff --git a/libpod/runtime.go b/libpod/runtime.go
index c69854a17..fbd4c7529 100644
--- a/libpod/runtime.go
+++ b/libpod/runtime.go
@@ -172,6 +172,8 @@ type RuntimeConfig struct {
 	// However, this can cause significant memory usage if a container has
 	// many ports forwarded to it. Disabling this can save memory.
 	EnablePortReservation bool `toml:"enable_port_reservation"`
+	// EnableLabeling indicates wether libpod will support container labeling
+	EnableLabeling bool `toml:"label"`
 }
 
 var (
@@ -209,6 +211,7 @@ var (
 		InfraCommand:          DefaultInfraCommand,
 		InfraImage:            DefaultInfraImage,
 		EnablePortReservation: true,
+		EnableLabeling:        true,
 	}
 )
 
diff --git a/libpod/runtime_ctr.go b/libpod/runtime_ctr.go
index a0b576bcd..6c487e367 100644
--- a/libpod/runtime_ctr.go
+++ b/libpod/runtime_ctr.go
@@ -11,6 +11,7 @@ import (
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/stringid"
 	spec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/opencontainers/selinux/go-selinux/label"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"github.com/ulule/deepcopier"
@@ -77,6 +78,7 @@ func (r *Runtime) newContainer(ctx context.Context, rSpec *spec.Spec, options ..
 		ctr.config.Namespace = r.config.Namespace
 	}
 
+	ctr.runtime = r
 	for _, option := range options {
 		if err := option(ctr); err != nil {
 			return nil, errors.Wrapf(err, "error running container create option")
@@ -85,7 +87,6 @@ func (r *Runtime) newContainer(ctx context.Context, rSpec *spec.Spec, options ..
 
 	ctr.valid = true
 	ctr.state.State = ContainerStateConfigured
-	ctr.runtime = r
 
 	var pod *Pod
 	if ctr.config.Pod != "" {
@@ -327,6 +328,10 @@ func (r *Runtime) removeContainer(ctx context.Context, c *Container, force bool)
 		}
 	}
 
+	if r.config.EnableLabeling {
+		label.ReleaseLabel(c.ProcessLabel())
+		r.reserveLabels()
+	}
 	// Delete the container
 	// Only do this if we're not ContainerStateConfigured - if we are,
 	// we haven't been created in the runtime yet
@@ -460,3 +465,28 @@ func (r *Runtime) GetLatestContainer() (*Container, error) {
 	}
 	return ctrs[lastCreatedIndex], nil
 }
+
+// reserveLabels walks the list o fcontainers and reserves the label, so new containers will not
+// get them.
+// TODO Performance wise this should only run if the state has changed since the last time it was run.
+func (r *Runtime) reserveLabels() error {
+	containers, err := r.state.AllContainers()
+	if err != nil {
+		return err
+	}
+	for _, ctr := range containers {
+		label.ReserveLabel(ctr.ProcessLabel())
+	}
+	return nil
+}
+
+// initLabels allocates an new label to return to the caller
+func (r *Runtime) initLabels(labelOpts []string) (string, string, error) {
+	if !r.config.EnableLabeling {
+		return "", "", nil
+	}
+	if err := r.reserveLabels(); err != nil {
+		return "", "", errors.Wrapf(err, "unable to reserve labels")
+	}
+	return label.InitLabels(labelOpts)
+}