Add a flag to reject privileged containers in the apiserver.

cmd/apiserver/apiserver.go

@@ -28,6 +28,7 @@ import (
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/apiserver"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/cloudprovider"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/master"
@@ -49,6 +50,7 @@ var (
 	etcdServerList        util.StringList
 	machineList           util.StringList
 	corsAllowedOriginList util.StringList
+	allowPrivileged       = flag.Bool("allow_privileged", false, "If true, allow privileged containers.")
 )
 
 func init() {
@@ -112,6 +114,10 @@ func main() {
 		glog.Fatalf("-etcd_servers flag is required.")
 	}
 
+	capabilities.InitializeCapabilities(capabilities.Capabilities{
+		AllowPrivileged: *allowPrivileged,
+	})
+
 	cloud := initCloudProvider(*cloudProvider, *cloudConfigFile)
 
 	podInfoGetter := &client.HTTPPodInfoGetter{

cmd/kubelet/kubelet.go

@@ -30,6 +30,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/health"
 	_ "github.com/GoogleCloudPlatform/kubernetes/pkg/healthz"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet"
@@ -59,7 +60,7 @@ var (
 	dockerEndpoint     = flag.String("docker_endpoint", "", "If non-empty, use this for the docker endpoint to communicate with")
 	etcdServerList     util.StringList
 	rootDirectory      = flag.String("root_dir", defaultRootDir, "Directory path for managing kubelet files (volume mounts,etc).")
-	allowPrivileged    = flag.Bool("allow_privileged", false, "If true, allow containers to request privileged mode.")
+	allowPrivileged    = flag.Bool("allow_privileged", false, "If true, allow containers to request privileged mode. [default=false]")
 )
 
 func init() {
@@ -104,6 +105,10 @@ func main() {
 
 	etcd.SetLogger(util.NewLogger("etcd "))
 
+	capabilities.InitializeCapabilities(capabilities.Capabilities{
+		AllowPrivileged: *allowPrivileged,
+	})
+
 	dockerClient, err := docker.NewClient(getDockerEndpoint())
 	if err != nil {
 		glog.Fatal("Couldn't connect to docker.")
@@ -152,8 +157,7 @@ func main() {
 		cadvisorClient,
 		etcdClient,
 		*rootDirectory,
-		*syncFrequency,
-		*allowPrivileged)
+		*syncFrequency)
 
 	health.AddHealthChecker("exec", health.NewExecHealthChecker(k))
 	health.AddHealthChecker("http", health.NewHTTPHealthChecker(&http.Client{}))

pkg/api/validation/validation.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	errs "github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 )
@@ -226,12 +227,15 @@ func validateContainers(containers []api.Container, volumes util.StringSet) errs
 	for i := range containers {
 		cErrs := errs.ErrorList{}
 		ctr := &containers[i] // so we can set default values
+		capabilities := capabilities.GetCapabilities()
 		if len(ctr.Name) == 0 {
 			cErrs = append(cErrs, errs.NewFieldRequired("name", ctr.Name))
 		} else if !util.IsDNSLabel(ctr.Name) {
 			cErrs = append(cErrs, errs.NewFieldInvalid("name", ctr.Name))
 		} else if allNames.Has(ctr.Name) {
 			cErrs = append(cErrs, errs.NewFieldDuplicate("name", ctr.Name))
+		} else if ctr.Privileged && !capabilities.AllowPrivileged {
+			cErrs = append(cErrs, errs.NewFieldInvalid("privileged", ctr.Privileged))
 		} else {
 			allNames.Insert(ctr.Name)
 		}

pkg/api/validation/validation_test.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 )
 
@@ -179,6 +180,9 @@ func TestValidateVolumeMounts(t *testing.T) {
 
 func TestValidateContainers(t *testing.T) {
 	volumes := util.StringSet{}
+	capabilities.SetCapabilitiesForTests(capabilities.Capabilities{
+		AllowPrivileged: true,
+	})
 
 	successCase := []api.Container{
 		{Name: "abc", Image: "image"},
@@ -193,11 +197,15 @@ func TestValidateContainers(t *testing.T) {
 				},
 			},
 		},
+		{Name: "abc-1234", Image: "image", Privileged: true},
 	}
 	if errs := validateContainers(successCase, volumes); len(errs) != 0 {
 		t.Errorf("expected success: %v", errs)
 	}
 
+	capabilities.SetCapabilitiesForTests(capabilities.Capabilities{
+		AllowPrivileged: false,
+	})
 	errorCases := map[string][]api.Container{
 		"zero-length name":     {{Name: "", Image: "image"}},
 		"name > 63 characters": {{Name: strings.Repeat("a", 64), Image: "image"}},
@@ -248,6 +256,9 @@ func TestValidateContainers(t *testing.T) {
 				},
 			},
 		},
+		"privilege disabled": {
+			{Name: "abc", Image: "image", Privileged: true},
+		},
 	}
 	for k, v := range errorCases {
 		if errs := validateContainers(v, volumes); len(errs) == 0 {

pkg/capabilities/capabilities.go

@@ -0,0 +1,53 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package capabilities
+
+import (
+	"sync"
+)
+
+// Capabilities defines the set of capabilities available within the system.
+// For now these are global.  Eventually they may be per-user
+type Capabilities struct {
+	AllowPrivileged bool
+}
+
+var once sync.Once
+var capabilities *Capabilities
+
+// Initialize the capability set.  This can only be done once per binary, subsequent calls are ignored.
+func InitializeCapabilities(c Capabilities) {
+	// Only do this once
+	once.Do(func() {
+		capabilities = &c
+	})
+}
+
+// SetCapabilitiesForTests.  Convenience method for testing.  This should only be called from tests.
+func SetCapabilitiesForTests(c Capabilities) {
+	capabilities = &c
+}
+
+// Returns a read-only copy of the system capabilities.
+func GetCapabilities() Capabilities {
+	if capabilities == nil {
+		InitializeCapabilities(Capabilities{
+			AllowPrivileged: false,
+		})
+	}
+	return *capabilities
+}

pkg/capabilities/doc.go

@@ -0,0 +1,18 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// package capbabilities manages system level capabilities
+package capabilities

pkg/kubelet/kubelet.go

@@ -29,6 +29,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/validation"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/health"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/dockertools"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
@@ -67,19 +68,17 @@ func NewMainKubelet(
 	cc CadvisorInterface,
 	ec tools.EtcdClient,
 	rd string,
-	ri time.Duration,
-	privileged bool) *Kubelet {
+	ri time.Duration) *Kubelet {
 	return &Kubelet{
-		hostname:        hn,
-		dockerClient:    dc,
-		cadvisorClient:  cc,
-		etcdClient:      ec,
-		rootDirectory:   rd,
-		resyncInterval:  ri,
-		podWorkers:      newPodWorkers(),
-		runner:          dockertools.NewDockerContainerCommandRunner(),
-		httpClient:      &http.Client{},
-		allowPrivileged: privileged,
+		hostname:       hn,
+		dockerClient:   dc,
+		cadvisorClient: cc,
+		etcdClient:     ec,
+		rootDirectory:  rd,
+		resyncInterval: ri,
+		podWorkers:     newPodWorkers(),
+		runner:         dockertools.NewDockerContainerCommandRunner(),
+		httpClient:     &http.Client{},
 	}
 }
 
@@ -121,8 +120,6 @@ type Kubelet struct {
 	runner dockertools.ContainerCommandRunner
 	// Optional, client for http requests, defaults to empty client
 	httpClient httpGetInterface
-	// Optional, allow privileged containers, defaults to false
-	allowPrivileged bool
 }
 
 // Run starts the kubelet reacting to config updates
@@ -340,7 +337,7 @@ func (kl *Kubelet) runContainer(pod *Pod, container *api.Container, podVolumes v
 		return "", err
 	}
 	privileged := false
-	if kl.allowPrivileged {
+	if capabilities.GetCapabilities().AllowPrivileged {
 		privileged = container.Privileged
 	} else if container.Privileged {
 		return "", fmt.Errorf("Container requested privileged mode, but it is disallowed globally.")