Add secure ciphersuites for TLS config (open-telemetry#1244)

* add secure ciphersuites for TLS config

* add comment for the secureCipherSuite function

* provide more descriptive comments on secureCipherSuite function

* ciphersuites and tls version setting can be configurable

* add description for the function tlsConfigSetting

go.mod

@@ -16,6 +16,7 @@ require (
 	k8s.io/api v0.25.4
 	k8s.io/apimachinery v0.25.4
 	k8s.io/client-go v0.25.4
+	k8s.io/component-base v0.25.4
 	k8s.io/kubectl v0.25.4
 	sigs.k8s.io/controller-runtime v0.13.1
 )
@@ -78,6 +79,7 @@ require (
 	github.com/hashicorp/serf v0.9.5 // indirect
 	github.com/hetznercloud/hcloud-go v1.26.2 // indirect
 	github.com/imdario/mergo v0.3.12 // indirect
+	github.com/inconshreveable/mousetrap v1.0.0 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/jpillora/backoff v1.0.0 // indirect
@@ -103,6 +105,7 @@ require (
 	github.com/prometheus/procfs v0.7.3 // indirect
 	github.com/scaleway/scaleway-sdk-go v1.0.0-beta.7.0.20210223165440-c65ae3540d44 // indirect
 	github.com/sirupsen/logrus v1.8.1 // indirect
+	github.com/spf13/cobra v1.4.0 // indirect
 	go.opencensus.io v0.23.0 // indirect
 	go.opentelemetry.io/otel/trace v1.11.1 // indirect
 	go.uber.org/atomic v1.8.0 // indirect
@@ -125,7 +128,6 @@ require (
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/apiextensions-apiserver v0.25.0 // indirect
-	k8s.io/component-base v0.25.4 // indirect
 	k8s.io/klog/v2 v2.70.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20220803162953-67bda5d908f1 // indirect
 	k8s.io/utils v0.0.0-20220728103510-ee6ede2d64ed // indirect

go.sum

@@ -213,6 +213,7 @@ github.com/coreos/go-semver v0.2.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3Ee
 github.com/coreos/go-systemd v0.0.0-20180511133405-39ca1b05acc7/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
+github.com/cpuguy83/go-md2man/v2 v2.0.1/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/creack/pty v1.1.11/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
@@ -632,6 +633,7 @@ github.com/imdario/mergo v0.3.4/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJ
 github.com/imdario/mergo v0.3.5/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
 github.com/imdario/mergo v0.3.12 h1:b6R2BslTbIEToALKP7LxUvijTsNI9TAe80pLWN2g/HU=
 github.com/imdario/mergo v0.3.12/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=
+github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NHg9XEKhtSvM=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/influxdata/flux v0.65.0/go.mod h1:BwN2XG2lMszOoquQaFdPET8FRQfrXiZsWmcMO9rkaVY=
 github.com/influxdata/flux v0.113.0/go.mod h1:3TJtvbm/Kwuo5/PEo5P6HUzwVg4bXWkb2wPQHPtQdlU=
@@ -915,6 +917,7 @@ github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFR
 github.com/rs/cors v1.6.0/go.mod h1:gFx+x8UowdsKA9AchylcLynDq+nNFfI8FkUZdN/jGCU=
 github.com/rs/cors v1.7.0/go.mod h1:gFx+x8UowdsKA9AchylcLynDq+nNFfI8FkUZdN/jGCU=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/ryanuber/columnize v2.1.0+incompatible/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/samuel/go-zookeeper v0.0.0-20190923202752-2cc03de413da/go.mod h1:gi+0XIa01GRL2eRQVjQkKGqKF3SF9vZR/HnPullcV2E=
@@ -947,6 +950,8 @@ github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasO
 github.com/spf13/afero v1.2.2/go.mod h1:9ZxEEn6pIJ8Rxe320qSDBk6AsU0r9pR7Q4OcevTdifk=
 github.com/spf13/cast v1.3.0/go.mod h1:Qx5cxh0v+4UWYiBimWS+eyWzqEqokIECu5etghLkUJE=
 github.com/spf13/cobra v0.0.3/go.mod h1:1l0Ry5zgKvJasoi3XT1TypsSe7PqH0Sj9dhYf7v3XqQ=
+github.com/spf13/cobra v1.4.0 h1:y+wJpx64xcgO1V+RcnwW0LEHxTKRi2ZDPSBjWnrg88Q=
+github.com/spf13/cobra v1.4.0/go.mod h1:Wo4iy3BUC+X2Fybo0PDqwJIv3dNRiZLHQymsfxlB84g=
 github.com/spf13/pflag v0.0.0-20170130214245-9ff6c6923cff/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/pflag v1.0.1/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=

main.go

@@ -31,6 +31,7 @@ import (
 	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
 	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
 	"k8s.io/client-go/tools/record"
+	k8sapiflag "k8s.io/component-base/cli/flag"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/cache"
 	"sigs.k8s.io/controller-runtime/pkg/healthz"
@@ -51,15 +52,16 @@ import (
 	// +kubebuilder:scaffold:imports
 )
 
-// We should avoid that users unknowingly use a vulnerable TLS version.
-// The defaults should be a safe configuration.
-const defaultMinTLSVersion = tls.VersionTLS12
-
 var (
 	scheme   = k8sruntime.NewScheme()
 	setupLog = ctrl.Log.WithName("setup")
 )
 
+type tlsConfig struct {
+	minVersion   string
+	cipherSuites []string
+}
+
 func init() {
 	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
 
@@ -88,6 +90,7 @@ func main() {
 		autoInstrumentationDotNet string
 		labelsFilter              []string
 		webhookPort               int
+		tlsOpt                    tlsConfig
 	)
 
 	pflag.StringVar(&metricsAddr, "metrics-addr", ":8080", "The address the metric endpoint binds to.")
@@ -103,6 +106,8 @@ func main() {
 	pflag.StringVar(&autoInstrumentationDotNet, "auto-instrumentation-dotnet-image", fmt.Sprintf("ghcr.io/open-telemetry/opentelemetry-operator/autoinstrumentation-dotnet:%s", v.AutoInstrumentationDotNet), "The default OpenTelemetry DotNet instrumentation image. This image is used when no image is specified in the CustomResource.")
 	pflag.StringArrayVar(&labelsFilter, "labels", []string{}, "Labels to filter away from propagating onto deploys")
 	pflag.IntVar(&webhookPort, "webhook-port", 9443, "The port the webhook endpoint binds to.")
+	pflag.StringVar(&tlsOpt.minVersion, "tls-min-version", "VersionTLS12", "Minimum TLS version supported. Value must match version names from https://golang.org/pkg/crypto/tls/#pkg-constants.")
+	pflag.StringSliceVar(&tlsOpt.cipherSuites, "tls-cipher-suites", nil, "Comma-separated list of cipher suites for the server. Values are from tls package constants (https://golang.org/pkg/crypto/tls/#pkg-constants). If omitted, the default Go cipher suites will be used")
 	pflag.Parse()
 
 	logger := zap.New(zap.UseFlagOptions(&opts))
@@ -158,7 +163,7 @@ func main() {
 	retryPeriod := time.Second * 26
 
 	optionsTlSOptsFuncs := []func(*tls.Config){
-		func(config *tls.Config) { minTlsDefault(config) },
+		func(config *tls.Config) { tlsConfigSetting(config, tlsOpt) },
 	}
 
 	mgrOptions := ctrl.Options{
@@ -289,6 +294,21 @@ func addDependencies(_ context.Context, mgr ctrl.Manager, cfg config.Config, v v
 	return nil
 }
 
-func minTlsDefault(cfg *tls.Config) {
-	cfg.MinVersion = defaultMinTLSVersion
+// This function get the option from command argument (tlsConfig), check the validity through k8sapiflag
+// and set the config for webhook server.
+// refer to https://pkg.go.dev/k8s.io/component-base/cli/flag
+func tlsConfigSetting(cfg *tls.Config, tlsOpt tlsConfig) {
+	// TLSVersion helper function returns the TLS Version ID for the version name passed.
+	version, err := k8sapiflag.TLSVersion(tlsOpt.minVersion)
+	if err != nil {
+		setupLog.Error(err, "TLS version invalid")
+	}
+	cfg.MinVersion = version
+
+	// TLSCipherSuites helper function returns a list of cipher suite IDs from the cipher suite names passed.
+	cipherSuiteIDs, err := k8sapiflag.TLSCipherSuites(tlsOpt.cipherSuites)
+	if err != nil {
+		setupLog.Error(err, "Failed to convert TLS cipher suite name to ID")
+	}
+	cfg.CipherSuites = cipherSuiteIDs
 }