Implement TLS server authentication

Add support for TLS authentication. When enabled, nfd-worker verifies
that nfd-master has a valid certificate, i.e. signed by the given root
certificate and its Common Name (CN) matches the DNS name of the
nfd-master service being used. TLS authentication is enabled by
specifying --key-file and --cert-file on nfd-master, and, --ca-file on
nfd-worker.

cmd/nfd-master/main.go

@@ -29,6 +29,7 @@ import (
 	"github.com/docopt/docopt-go"
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
 	"sigs.k8s.io/node-feature-discovery/pkg/apihelper"
 	pb "sigs.k8s.io/node-feature-discovery/pkg/labeler"
 	"sigs.k8s.io/node-feature-discovery/pkg/version"
@@ -62,6 +63,8 @@ type Annotations map[string]string
 
 // Command line arguments
 type Args struct {
+	certFile       string
+	keyFile        string
 	labelWhiteList *regexp.Regexp
 	noPublish      bool
 	port           int
@@ -95,7 +98,17 @@ func main() {
 	if err != nil {
 		stderrLogger.Fatalf("failed to listen: %v", err)
 	}
-	grpcServer := grpc.NewServer()
+
+	serverOpts := []grpc.ServerOption{}
+	// Use TLS if --cert-file or --key-file is defined
+	if args.certFile != "" || args.keyFile != "" {
+		creds, err := credentials.NewServerTLSFromFile(args.certFile, args.keyFile)
+		if err != nil {
+			log.Fatalf("Failed to generate credentials %v", err)
+		}
+		serverOpts = append(serverOpts, grpc.Creds(creds))
+	}
+	grpcServer := grpc.NewServer(serverOpts...)
 	pb.RegisterLabelerServer(grpcServer, &labelerServer{args: args, apiHelper: helper})
 	stdoutLogger.Printf("gRPC server serving on port: %d", args.port)
 	grpcServer.Serve(lis)
@@ -109,6 +122,7 @@ func argsParse(argv []string) (Args, error) {
 
   Usage:
   %s [--no-publish] [--label-whitelist=<pattern>] [--port=<port>]
+     [--cert-file=<path>] [--key-file=<path>]
   %s -h | --help
   %s --version
 
@@ -117,6 +131,10 @@ func argsParse(argv []string) (Args, error) {
   --version                   Output version and exit.
   --port=<port>               Port on which to listen for connections.
                               [Default: 8080]
+  --cert-file=<path>          Certificate used for authenticating connections
+                              [Default: ]
+  --key-file=<path>           Private key matching --cert-file
+                              [Default: ]
   --no-publish                Do not publish feature labels
   --label-whitelist=<pattern> Regular expression to filter label names to
                               publish to the Kubernetes API server. [Default: ]`,
@@ -131,6 +149,8 @@ func argsParse(argv []string) (Args, error) {
 
 	// Parse argument values as usable types.
 	var err error
+	args.certFile = arguments["--cert-file"].(string)
+	args.keyFile = arguments["--key-file"].(string)
 	args.noPublish = arguments["--no-publish"].(bool)
 	args.port, err = strconv.Atoi(arguments["--port"].(string))
 	if err != nil {
@@ -141,6 +161,15 @@ func argsParse(argv []string) (Args, error) {
 		return args, fmt.Errorf("error parsing whitelist regex (%s): %s", arguments["--label-whitelist"], err)
 	}
 
+	// Check TLS related args
+	if args.certFile != "" || args.keyFile != "" {
+		if args.certFile == "" {
+			return args, fmt.Errorf("--cert-file needs to be specified alongside --key-file")
+		}
+		if args.keyFile == "" {
+			return args, fmt.Errorf("--key-file needs to be specified alongside --cert-file")
+		}
+	}
 	return args, nil
 }
 

cmd/nfd-master/main_test.go

@@ -223,10 +223,12 @@ func TestArgsParse(t *testing.T) {
 		})
 
 		Convey("When valid args are specified", func() {
-			args, err := argsParse([]string{"--label-whitelist=.*rdt.*", "--port=1234"})
+			args, err := argsParse([]string{"--label-whitelist=.*rdt.*", "--port=1234", "--cert-file=crt", "--key-file=key"})
 			Convey("Argument parsing should succeed and args set to correct values", func() {
 				So(args.noPublish, ShouldBeFalse)
 				So(args.port, ShouldEqual, 1234)
+				So(args.certFile, ShouldEqual, "crt")
+				So(args.keyFile, ShouldEqual, "key")
 				So(args.labelWhiteList.String(), ShouldResemble, ".*rdt.*")
 				So(err, ShouldBeNil)
 			})
@@ -237,5 +239,14 @@ func TestArgsParse(t *testing.T) {
 				So(err, ShouldNotBeNil)
 			})
 		})
+
+		Convey("When --cert-file or --key-file is specified on its own", func() {
+			_, err := argsParse([]string{"--cert-file=crt"})
+			_, err2 := argsParse([]string{"--key-file=key"})
+			Convey("argsParse should fail", func() {
+				So(err, ShouldNotBeNil)
+				So(err2, ShouldNotBeNil)
+			})
+		})
 	})
 }

cmd/nfd-worker/main.go

@@ -29,6 +29,7 @@ import (
 	"github.com/ghodss/yaml"
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
 	"k8s.io/apimachinery/pkg/util/validation"
 	pb "sigs.k8s.io/node-feature-discovery/pkg/labeler"
 	"sigs.k8s.io/node-feature-discovery/pkg/version"
@@ -82,6 +83,7 @@ type Annotations map[string]string
 // Command line arguments
 type Args struct {
 	labelWhiteList string
+	caFile         string
 	configFile     string
 	noPublish      bool
 	options        string
@@ -117,8 +119,17 @@ func main() {
 	}
 
 	// Connect to NFD server
-	opts := []grpc.DialOption{grpc.WithInsecure()}
-	conn, err := grpc.Dial(args.server, opts...)
+	dialOpts := []grpc.DialOption{}
+	if args.caFile != "" {
+		creds, err := credentials.NewClientTLSFromFile(args.caFile, "")
+		if err != nil {
+			stderrLogger.Fatalf("failed to create credentials %v", err)
+		}
+		dialOpts = append(dialOpts, grpc.WithTransportCredentials(creds))
+	} else {
+		dialOpts = append(dialOpts, grpc.WithInsecure())
+	}
+	conn, err := grpc.Dial(args.server, dialOpts...)
 	if err != nil {
 		stderrLogger.Fatalf("failed to connect: %v", err)
 	}
@@ -160,7 +171,7 @@ func argsParse(argv []string) (Args, error) {
   Usage:
   %s [--no-publish] [--sources=<sources>] [--label-whitelist=<pattern>]
      [--oneshot | --sleep-interval=<seconds>] [--config=<path>]
-     [--options=<config>] [--server=<server>]
+     [--options=<config>] [--ca-file=<path>] [--server=<server>]
   %s -h | --help
   %s --version
 
@@ -174,6 +185,8 @@ func argsParse(argv []string) (Args, error) {
                               config file (i.e. json or yaml). These options
                               will override settings read from the config file.
                               [Default: ]
+  --ca-file=<path>            Root certificate for verifying connections
+                              [Default: ]
   --server=<server>           NFD server address to connecto to.
                               [Default: localhost:8080]
   --sources=<sources>         Comma separated list of feature sources.
@@ -197,6 +210,7 @@ func argsParse(argv []string) (Args, error) {
 
 	// Parse argument values as usable types.
 	var err error
+	args.caFile = arguments["--ca-file"].(string)
 	args.configFile = arguments["--config"].(string)
 	args.noPublish = arguments["--no-publish"].(bool)
 	args.options = arguments["--options"].(string)

cmd/nfd-worker/main_test.go

@@ -116,11 +116,12 @@ func TestArgsParse(t *testing.T) {
 			})
 		})
 
-		Convey("When --no-publish and --sources flag are passed and --sources flag is set to some value", func() {
-			args, err := argsParse([]string{"--no-publish", "--sources=fake1,fake2,fake3"})
+		Convey("When valid args are specified", func() {
+			args, err := argsParse([]string{"--no-publish", "--sources=fake1,fake2,fake3", "--ca-file=ca"})
 
 			Convey("--no-publish is set and args.sources is set to appropriate values", func() {
 				So(args.noPublish, ShouldBeTrue)
+				So(args.caFile, ShouldEqual, "ca")
 				So(args.sources, ShouldResemble, []string{"fake1", "fake2", "fake3"})
 				So(len(args.labelWhiteList), ShouldEqual, 0)
 				So(err, ShouldBeNil)

nfd-worker-daemonset.yaml.template

@@ -14,6 +14,7 @@ spec:
         app: nfd-worker
     spec:
       hostNetwork: true
+      dnsPolicy: ClusterFirstWithHostNet
       containers:
         - env:
           - name: NODE_NAME
@@ -26,7 +27,7 @@ spec:
             - "nfd-worker"
           args:
             - "--sleep-interval=60s"
-            - "--server=$(NFD_MASTER_SERVICE_HOST):$(NFD_MASTER_SERVICE_PORT)"
+            - "--server=nfd-master:8080"
           volumeMounts:
             - name: host-boot
               mountPath: "/host-boot"

nfd-worker-job.yaml.template

@@ -13,6 +13,7 @@ spec:
         app: node-feature-discovery
     spec:
       hostNetwork: true
+      dnsPolicy: ClusterFirstWithHostNet
       containers:
         - env:
           - name: NODE_NAME
@@ -25,7 +26,7 @@ spec:
             - "nfd-worker"
           args:
             - "--oneshot"
-            - "--server=$(NFD_MASTER_SERVICE_HOST):$(NFD_MASTER_SERVICE_PORT)"
+            - "--server=nfd-master:8080"
           ports:
             - containerPort: 7156
               hostPort: 7156