Merge branch 'main' into upstream_refresh_revocation_during_gc

CONTRIBUTING.md

@@ -114,11 +114,12 @@ docker build .
    - [`kind`](https://kind.sigs.k8s.io/docs/user/quick-start)
    - [`kubectl`](https://kubernetes.io/docs/tasks/tools/install-kubectl/)
    - [`ytt`](https://carvel.dev/#getting-started)
+   - [`nmap`](https://nmap.org/download.html)
 
    On macOS, these tools can be installed with [Homebrew](https://brew.sh/) (assuming you have Chrome installed already):
 
    ```bash
-   brew install kind k14s/tap/ytt k14s/tap/kapp kubectl chromedriver && brew cask install docker
+   brew install kind k14s/tap/ytt k14s/tap/kapp kubectl chromedriver nmap && brew cask install docker
    ```
 
 1. Create a kind cluster, compile, create container images, and install Pinniped and supporting dependencies using:

cmd/pinniped/cmd/kubeconfig.go

@@ -5,7 +5,6 @@ package cmd
 
 import (
 	"context"
-	"crypto/tls"
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
@@ -28,13 +27,13 @@ import (
 	_ "k8s.io/client-go/plugin/pkg/client/auth" // Adds handlers for various dynamic auth plugins in client-go
 	"k8s.io/client-go/tools/clientcmd"
 	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
-	"k8s.io/client-go/transport"
 
 	conciergev1alpha1 "go.pinniped.dev/generated/latest/apis/concierge/authentication/v1alpha1"
 	configv1alpha1 "go.pinniped.dev/generated/latest/apis/concierge/config/v1alpha1"
 	idpdiscoveryv1alpha1 "go.pinniped.dev/generated/latest/apis/supervisor/idpdiscovery/v1alpha1"
 	conciergeclientset "go.pinniped.dev/generated/latest/client/concierge/clientset/versioned"
 	"go.pinniped.dev/internal/groupsuffix"
+	"go.pinniped.dev/internal/net/phttp"
 )
 
 type kubeconfigDeps struct {
@@ -664,17 +663,8 @@ func validateKubeconfig(ctx context.Context, flags getKubeconfigParams, kubeconf
 		return fmt.Errorf("invalid kubeconfig (no certificateAuthorityData)")
 	}
 
-	httpClient := &http.Client{
+	httpClient := phttp.Default(kubeconfigCA)
-		Transport: &http.Transport{
+	httpClient.Timeout = 10 * time.Second
-			TLSClientConfig: &tls.Config{
-				MinVersion: tls.VersionTLS12,
-				RootCAs:    kubeconfigCA,
-			},
-			Proxy:               http.ProxyFromEnvironment,
-			TLSHandshakeTimeout: 10 * time.Second,
-		},
-		Timeout: 10 * time.Second,
-	}
 
 	ticker := time.NewTicker(2 * time.Second)
 	defer ticker.Stop()
@@ -781,21 +771,14 @@ func discoverSupervisorUpstreamIDP(ctx context.Context, flags *getKubeconfigPara
 }
 
 func newDiscoveryHTTPClient(caBundleFlag caBundleFlag) (*http.Client, error) {
-	t := &http.Transport{
+	var rootCAs *x509.CertPool
-		TLSClientConfig: &tls.Config{MinVersion: tls.VersionTLS12},
-		Proxy:           http.ProxyFromEnvironment,
-	}
-	httpClient := &http.Client{Transport: t}
 	if caBundleFlag != nil {
-		rootCAs := x509.NewCertPool()
+		rootCAs = x509.NewCertPool()
-		ok := rootCAs.AppendCertsFromPEM(caBundleFlag)
+		if ok := rootCAs.AppendCertsFromPEM(caBundleFlag); !ok {
-		if !ok {
 			return nil, fmt.Errorf("unable to fetch OIDC discovery data from issuer: could not parse CA bundle")
 		}
-		t.TLSClientConfig.RootCAs = rootCAs
 	}
-	httpClient.Transport = transport.DebugWrappers(httpClient.Transport)
+	return phttp.Default(rootCAs), nil
-	return httpClient, nil
 }
 
 func discoverIDPsDiscoveryEndpointURL(ctx context.Context, issuer string, httpClient *http.Client) (string, error) {

cmd/pinniped/cmd/login_oidc.go

@@ -5,7 +5,6 @@ package cmd
 
 import (
 	"context"
-	"crypto/tls"
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
@@ -21,12 +20,12 @@ import (
 	"github.com/spf13/cobra"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	clientauthv1beta1 "k8s.io/client-go/pkg/apis/clientauthentication/v1beta1"
-	"k8s.io/client-go/transport"
 	"k8s.io/klog/v2/klogr"
 
 	idpdiscoveryv1alpha1 "go.pinniped.dev/generated/latest/apis/supervisor/idpdiscovery/v1alpha1"
 	"go.pinniped.dev/internal/execcredcache"
 	"go.pinniped.dev/internal/groupsuffix"
+	"go.pinniped.dev/internal/net/phttp"
 	"go.pinniped.dev/internal/plog"
 	"go.pinniped.dev/pkg/conciergeclient"
 	"go.pinniped.dev/pkg/oidcclient"
@@ -308,18 +307,7 @@ func makeClient(caBundlePaths []string, caBundleData []string) (*http.Client, er
 		}
 		pool.AppendCertsFromPEM(pem)
 	}
-	client := &http.Client{
+	return phttp.Default(pool), nil
-		Transport: &http.Transport{
-			Proxy: http.ProxyFromEnvironment,
-			TLSClientConfig: &tls.Config{
-				RootCAs:    pool,
-				MinVersion: tls.VersionTLS12,
-			},
-		},
-	}
-
-	client.Transport = transport.DebugWrappers(client.Transport)
-	return client, nil
 }
 
 func tokenCredential(token *oidctypes.Token) *clientauthv1beta1.ExecCredential {
@@ -338,7 +326,7 @@ func tokenCredential(token *oidctypes.Token) *clientauthv1beta1.ExecCredential {
 	return &cred
 }
 
-func SetLogLevel(lookupEnv func(string) (string, bool)) (*plog.PLogger, error) {
+func SetLogLevel(lookupEnv func(string) (string, bool)) (plog.Logger, error) {
 	debug, _ := lookupEnv("PINNIPED_DEBUG")
 	if debug == "true" {
 		err := plog.ValidateAndSetLogLevelGlobally(plog.LevelDebug)
@@ -347,7 +335,7 @@ func SetLogLevel(lookupEnv func(string) (string, bool)) (*plog.PLogger, error) {
 		}
 	}
 	logger := plog.New("Pinniped login: ")
-	return &logger, nil
+	return logger, nil
 }
 
 // mustGetConfigDir returns a directory that follows the XDG base directory convention:

hack/prepare-for-integration-tests.sh

@@ -132,6 +132,7 @@ check_dependency kubectl "Please install kubectl. e.g. 'brew install kubectl' fo
 check_dependency htpasswd "Please install htpasswd. Should be pre-installed on MacOS. Usually found in 'apache2-utils' package for linux."
 check_dependency openssl "Please install openssl. Should be pre-installed on MacOS."
 check_dependency chromedriver "Please install chromedriver. e.g. 'brew install chromedriver' for MacOS"
+check_dependency nmap "Please install nmap. e.g. 'brew install nmap' for MacOS"
 
 # Check that Chrome and chromedriver versions match. If chromedriver falls a couple versions behind
 # then usually tests start to fail with strange error messages.
@@ -158,6 +159,12 @@ if [ "$(kubectl version --client=true --short | cut -d '.' -f 2)" -lt 18 ]; then
   exit 1
 fi
 
+# Require nmap >= 7.92.x
+if [ "$(nmap -V | grep 'Nmap version' | cut -d ' ' -f 3 | cut -d '.' -f 2)" -lt 92 ]; then
+  log_error "nmap >= 7.92.x is required, you have $(nmap -V | grep 'Nmap version' | cut -d ' ' -f 3)"
+  exit 1
+fi
+
 if [[ "$clean_kind" == "yes" ]]; then
   log_note "Deleting running kind cluster to prepare from a clean slate..."
   ./hack/kind-down.sh

internal/concierge/impersonator/impersonator.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net"
 	"net/http"
 	"net/http/httputil"
@@ -14,6 +15,7 @@ import (
 	"os"
 	"regexp"
 	"strings"
+	"sync"
 	"time"
 
 	authenticationv1 "k8s.io/api/authentication/v1"
@@ -47,6 +49,7 @@ import (
 	"k8s.io/client-go/transport"
 
 	"go.pinniped.dev/internal/constable"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/dynamiccert"
 	"go.pinniped.dev/internal/httputil/securityheader"
 	"go.pinniped.dev/internal/kubeclient"
@@ -70,13 +73,14 @@ func New(
 	dynamicCertProvider dynamiccert.Private,
 	impersonationProxySignerCA dynamiccert.Public,
 ) (func(stopCh <-chan struct{}) error, error) {
-	return newInternal(port, dynamicCertProvider, impersonationProxySignerCA, nil, nil, nil)
+	return newInternal(port, dynamicCertProvider, impersonationProxySignerCA, kubeclient.Secure, nil, nil, nil)
 }
 
 func newInternal( //nolint:funlen // yeah, it's kind of long.
 	port int,
 	dynamicCertProvider dynamiccert.Private,
 	impersonationProxySignerCA dynamiccert.Public,
+	restConfigFunc ptls.RestConfigFunc, // for unit testing, should always be kubeclient.Secure in production
 	clientOpts []kubeclient.Option, // for unit testing, should always be nil in production
 	recOpts func(*genericoptions.RecommendedOptions), // for unit testing, should always be nil in production
 	recConfig func(*genericapiserver.RecommendedConfig), // for unit testing, should always be nil in production
@@ -100,6 +104,13 @@ func newInternal( //nolint:funlen // yeah, it's kind of long.
 		recommendedOptions.SecureServing.ServerCert.GeneratedCert = dynamicCertProvider // serving certs (end user facing)
 		recommendedOptions.SecureServing.BindPort = port
 
+		// secure TLS for connections coming from external clients and going to the Kube API server
+		// this is best effort because not all options provide the right hooks to override TLS config
+		// since any client could connect to the impersonation proxy, this uses the default TLS config
+		if err := ptls.DefaultRecommendedOptions(recommendedOptions, restConfigFunc); err != nil {
+			return nil, fmt.Errorf("failed to secure recommended options: %w", err)
+		}
+
 		// Wire up the impersonation proxy signer CA as another valid authenticator for client cert auth,
 		// along with the Kube API server's CA.
 		// Note: any changes to the Authentication stack need to be kept in sync with any assumptions made
@@ -258,7 +269,7 @@ func newInternal( //nolint:funlen // yeah, it's kind of long.
 
 		delegatingAuthorizer := serverConfig.Authorization.Authorizer
 		customReasonAuthorizer := &comparableAuthorizer{
-			authorizerFunc: func(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
+			AuthorizerFunc: func(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
 				const baseReason = "decision made by impersonation-proxy.concierge.pinniped.dev"
 				switch a.GetVerb() {
 				case "":
@@ -347,14 +358,14 @@ func getReverseProxyClient(clientOpts []kubeclient.Option) (*kubeclient.Client,
 	if err != nil {
 		return nil, err
 	}
-	impersonationProxyRestConfig = rest.AnonymousClientConfig(impersonationProxyRestConfig)
+	impersonationProxyRestConfig = kubeclient.SecureAnonymousClientConfig(impersonationProxyRestConfig)
 	impersonationProxyRestConfig.BearerTokenFile = tokenFile
 
 	return kubeclient.New(kubeclient.WithConfig(impersonationProxyRestConfig))
 }
 
 func isAnonymousAuthEnabled(config *rest.Config) (bool, error) {
-	anonymousConfig := rest.AnonymousClientConfig(config)
+	anonymousConfig := kubeclient.SecureAnonymousClientConfig(config)
 
 	// we do not need either of these but RESTClientFor complains if they are not set
 	anonymousConfig.GroupVersion = &schema.GroupVersion{}
@@ -413,14 +424,7 @@ type comparableAuthenticator struct {
 
 // No-op wrapping around AuthorizerFunc to allow for comparisons.
 type comparableAuthorizer struct {
-	authorizerFunc
+	authorizer.AuthorizerFunc
-}
-
-// TODO: delete when we pick up https://github.com/kubernetes/kubernetes/pull/100963
-type authorizerFunc func(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error)
-
-func (f authorizerFunc) Authorize(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
-	return f(ctx, a)
 }
 
 func withBearerTokenPreservation(delegate http.Handler) http.Handler {
@@ -462,16 +466,16 @@ func newImpersonationReverseProxyFunc(restConfig *rest.Config) (func(*genericapi
 	if err != nil {
 		return nil, fmt.Errorf("could not get http/1.1 round tripper: %w", err)
 	}
-	http1RoundTripperAnonymous, err := getTransportForProtocol(rest.AnonymousClientConfig(restConfig), "http/1.1")
+	http1RoundTripperAnonymous, err := getTransportForProtocol(kubeclient.SecureAnonymousClientConfig(restConfig), "http/1.1")
 	if err != nil {
 		return nil, fmt.Errorf("could not get http/1.1 anonymous round tripper: %w", err)
 	}
 
-	http2RoundTripper, err := getTransportForProtocol(restConfig, "h2")
+	http2RoundTripper, err := getTransportForProtocol(restConfig, "h2") // TODO figure out why this leads to still supporting http1
 	if err != nil {
 		return nil, fmt.Errorf("could not get http/2.0 round tripper: %w", err)
 	}
-	http2RoundTripperAnonymous, err := getTransportForProtocol(rest.AnonymousClientConfig(restConfig), "h2")
+	http2RoundTripperAnonymous, err := getTransportForProtocol(kubeclient.SecureAnonymousClientConfig(restConfig), "h2")
 	if err != nil {
 		return nil, fmt.Errorf("could not get http/2.0 anonymous round tripper: %w", err)
 	}
@@ -565,6 +569,12 @@ func newImpersonationReverseProxyFunc(restConfig *rest.Config) (func(*genericapi
 				r.Header.Del("X-Forwarded-For")
 			}
 
+			// the http2 code seems to call Close concurrently which can lead to data races
+			if r.Body != nil {
+				r = utilnet.CloneRequest(r)
+				r.Body = &safeReadWriteCloser{rc: r.Body}
+			}
+
 			reverseProxy := httputil.NewSingleHostReverseProxy(serverURL)
 			reverseProxy.Transport = rt
 			reverseProxy.FlushInterval = 200 * time.Millisecond // the "watch" verb will not work without this line
@@ -573,6 +583,43 @@ func newImpersonationReverseProxyFunc(restConfig *rest.Config) (func(*genericapi
 	}, nil
 }
 
+var _ io.ReadWriteCloser = &safeReadWriteCloser{}
+
+type safeReadWriteCloser struct {
+	m sync.Mutex // all methods allowed concurrently, this only guards concurrent calls to Close
+
+	rc io.ReadCloser
+
+	once     sync.Once // set up rwc and writeErr
+	rwc      io.ReadWriteCloser
+	writeErr error
+}
+
+func (r *safeReadWriteCloser) Read(p []byte) (int, error) {
+	return r.rc.Read(p)
+}
+
+func (r *safeReadWriteCloser) Write(p []byte) (int, error) {
+	r.once.Do(func() {
+		var ok bool
+		r.rwc, ok = r.rc.(io.ReadWriteCloser)
+		if !ok { // this method should only be caused during flows that switch protocols
+			r.writeErr = fmt.Errorf("switching protocols failed: io.ReadCloser %T is not io.ReadWriteCloser", r.rc)
+		}
+	})
+	if r.writeErr != nil {
+		return 0, r.writeErr
+	}
+	return r.rwc.Write(p)
+}
+
+func (r *safeReadWriteCloser) Close() error {
+	r.m.Lock()
+	defer r.m.Unlock()
+
+	return r.rc.Close()
+}
+
 func ensureNoImpersonationHeaders(r *http.Request) error {
 	for key := range r.Header {
 		// even though we have unit tests that try to cover this case, it is hard to tell if Go does
@@ -759,5 +806,14 @@ func getTransportForProtocol(restConfig *rest.Config, protocol string) (http.Rou
 	}
 	transportConfig.TLS.NextProtos = []string{protocol}
 
-	return transport.New(transportConfig)
+	rt, err := transport.New(transportConfig)
+	if err != nil {
+		return nil, fmt.Errorf("could not build transport: %w", err)
+	}
+
+	if err := kubeclient.AssertSecureTransport(rt); err != nil {
+		return nil, err // make sure we only use a secure TLS config
+	}
+
+	return rt, nil
 }

internal/concierge/impersonator/impersonator_test.go

@@ -36,6 +36,7 @@ import (
 	genericapiserver "k8s.io/apiserver/pkg/server"
 	genericoptions "k8s.io/apiserver/pkg/server/options"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd/api"
 	featuregatetesting "k8s.io/component-base/featuregate/testing"
@@ -44,12 +45,13 @@ import (
 	loginv1alpha1 "go.pinniped.dev/generated/latest/apis/concierge/login/v1alpha1"
 	"go.pinniped.dev/internal/certauthority"
 	"go.pinniped.dev/internal/constable"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/dynamiccert"
 	"go.pinniped.dev/internal/groupsuffix"
 	"go.pinniped.dev/internal/here"
 	"go.pinniped.dev/internal/httputil/roundtripper"
 	"go.pinniped.dev/internal/kubeclient"
-	"go.pinniped.dev/internal/testutil"
+	"go.pinniped.dev/internal/testutil/tlsserver"
 )
 
 func TestImpersonator(t *testing.T) {
@@ -697,7 +699,9 @@ func TestImpersonator(t *testing.T) {
 			// will proxy incoming calls to this fake server.
 			testKubeAPIServerWasCalled := false
 			var testKubeAPIServerSawHeaders http.Header
-			testKubeAPIServerCA, testKubeAPIServerURL := testutil.TLSTestServer(t, func(w http.ResponseWriter, r *http.Request) {
+			testKubeAPIServer := tlsserver.TLSTestServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				tlsserver.AssertTLS(t, r, ptls.Secure)
+
 				switch r.URL.Path {
 				case "/api/v1/namespaces/kube-system/configmaps":
 					require.Equal(t, http.MethodGet, r.Method)
@@ -708,6 +712,13 @@ func TestImpersonator(t *testing.T) {
 					http.NotFound(w, r)
 					return
 
+				case "/apis/flowcontrol.apiserver.k8s.io/v1beta1/prioritylevelconfigurations",
+					"/apis/flowcontrol.apiserver.k8s.io/v1beta1/flowschemas":
+					// ignore requests related to priority and fairness logic
+					require.Equal(t, http.MethodGet, r.Method)
+					http.NotFound(w, r)
+					return
+
 				case "/api/v1/namespaces":
 					require.Equal(t, http.MethodGet, r.Method)
 
@@ -785,13 +796,13 @@ func TestImpersonator(t *testing.T) {
 					require.Fail(t, "fake Kube API server got an unexpected request", "path: %s", r.URL.Path)
 					return
 				}
-			})
+			}), tlsserver.RecordTLSHello)
 
 			// Create the client config that the impersonation server should use to talk to the Kube API server.
 			testKubeAPIServerKubeconfig := rest.Config{
-				Host:            testKubeAPIServerURL,
+				Host:            testKubeAPIServer.URL,
 				BearerToken:     "some-service-account-token",
-				TLSClientConfig: rest.TLSClientConfig{CAData: []byte(testKubeAPIServerCA)},
+				TLSClientConfig: rest.TLSClientConfig{CAData: tlsserver.TLSTestServerCA(testKubeAPIServer)},
 				BearerTokenFile: tt.kubeAPIServerClientBearerTokenFile,
 			}
 			clientOpts := []kubeclient.Option{kubeclient.WithConfig(&testKubeAPIServerKubeconfig)}
@@ -800,7 +811,6 @@ func TestImpersonator(t *testing.T) {
 			recOpts := func(options *genericoptions.RecommendedOptions) {
 				options.Authentication.RemoteKubeConfigFileOptional = true
 				options.Authorization.RemoteKubeConfigFileOptional = true
-				options.CoreAPI = nil
 				options.Admission = nil
 				options.SecureServing.Listener = listener // use our listener with the dynamic port
 			}
@@ -814,8 +824,8 @@ func TestImpersonator(t *testing.T) {
 			// Allow standard REST verbs to be authorized so that tests pass without invasive changes
 			recConfig := func(config *genericapiserver.RecommendedConfig) {
 				authz := config.Authorization.Authorizer.(*comparableAuthorizer)
-				delegate := authz.authorizerFunc
+				delegate := authz.AuthorizerFunc
-				authz.authorizerFunc = func(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
+				authz.AuthorizerFunc = func(ctx context.Context, a authorizer.Attributes) (authorizer.Decision, string, error) {
 					recorder.record(a)
 					switch a.GetVerb() {
 					case "create", "get", "list":
@@ -826,8 +836,15 @@ func TestImpersonator(t *testing.T) {
 				}
 			}
 
+			restConfigFunc := func(config *rest.Config) (kubernetes.Interface, *rest.Config, error) {
+				if config == nil {
+					config = &testKubeAPIServerKubeconfig
+				}
+				return kubeclient.Secure(config)
+			}
+
 			// Create an impersonator.  Use an invalid port number to make sure our listener override works.
-			runner, constructionErr := newInternal(-1000, certKeyContent, caContent, clientOpts, recOpts, recConfig)
+			runner, constructionErr := newInternal(-1000, certKeyContent, caContent, restConfigFunc, clientOpts, recOpts, recConfig)
 			if len(tt.wantConstructionError) > 0 {
 				require.EqualError(t, constructionErr, tt.wantConstructionError)
 				require.Nil(t, runner)
@@ -864,7 +881,7 @@ func TestImpersonator(t *testing.T) {
 						return rt
 					}
 
-					return roundtripper.Func(func(req *http.Request) (*http.Response, error) {
+					return roundtripper.WrapFunc(rt, func(req *http.Request) (*http.Response, error) {
 						req = req.Clone(req.Context())
 						tt.clientMutateHeaders(req.Header)
 						return rt.RoundTrip(req)
@@ -928,10 +945,10 @@ func TestImpersonator(t *testing.T) {
 
 			// anonymous TCR should always work
 
-			tcrRegGroup, err := kubeclient.New(kubeclient.WithConfig(rest.AnonymousClientConfig(clientKubeconfig)))
+			tcrRegGroup, err := kubeclient.New(kubeclient.WithConfig(kubeclient.SecureAnonymousClientConfig(clientKubeconfig)))
 			require.NoError(t, err)
 
-			tcrOtherGroup, err := kubeclient.New(kubeclient.WithConfig(rest.AnonymousClientConfig(clientKubeconfig)),
+			tcrOtherGroup, err := kubeclient.New(kubeclient.WithConfig(kubeclient.SecureAnonymousClientConfig(clientKubeconfig)),
 				kubeclient.WithMiddleware(groupsuffix.New("walrus.tld")))
 			require.NoError(t, err)
 
@@ -950,7 +967,7 @@ func TestImpersonator(t *testing.T) {
 
 			// these calls should only work when anonymous auth is enabled
 
-			anonymousConfig := rest.AnonymousClientConfig(clientKubeconfig)
+			anonymousConfig := kubeclient.SecureAnonymousClientConfig(clientKubeconfig)
 			anonymousConfig.GroupVersion = &schema.GroupVersion{
 				Group:   "not-concierge.walrus.tld",
 				Version: "v1",
@@ -989,7 +1006,7 @@ func TestImpersonator(t *testing.T) {
 
 			// this should always fail as unauthorized (even for TCR) because the cert is not valid
 
-			badCertConfig := rest.AnonymousClientConfig(clientKubeconfig)
+			badCertConfig := kubeclient.SecureAnonymousClientConfig(clientKubeconfig)
 			badCert := newClientCert(t, unrelatedCA, "bad-user", []string{"bad-group"})
 			badCertConfig.TLSClientConfig.CertData = badCert.certPEM
 			badCertConfig.TLSClientConfig.KeyData = badCert.keyPEM
@@ -1041,7 +1058,7 @@ func TestImpersonatorHTTPHandler(t *testing.T) {
 				ExecProvider: &api.ExecConfig{},
 				AuthProvider: &api.AuthProviderConfig{},
 			},
-			wantCreationErr: "could not get http/1.1 round tripper: could not get in-cluster transport config: execProvider and authProvider cannot be used in combination",
+			wantCreationErr: "could not create secure client config: execProvider and authProvider cannot be used in combination",
 		},
 		{
 			name: "fail to get transport from config",
@@ -1051,7 +1068,7 @@ func TestImpersonatorHTTPHandler(t *testing.T) {
 				Transport:       http.DefaultTransport,
 				TLSClientConfig: rest.TLSClientConfig{Insecure: true},
 			},
-			wantCreationErr: "could not get http/1.1 round tripper: using a custom transport with TLS certificate options or the insecure flag is not allowed",
+			wantCreationErr: "could not create secure client config: failed to build transport: using a custom transport with TLS certificate options or the insecure flag is not allowed",
 		},
 		{
 			name:           "Impersonate-User header already in request",
@@ -1761,7 +1778,9 @@ func TestImpersonatorHTTPHandler(t *testing.T) {
 
 			testKubeAPIServerWasCalled := false
 			testKubeAPIServerSawHeaders := http.Header{}
-			testKubeAPIServerCA, testKubeAPIServerURL := testutil.TLSTestServer(t, func(w http.ResponseWriter, r *http.Request) {
+			testKubeAPIServer := tlsserver.TLSTestServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				tlsserver.AssertTLS(t, r, ptls.Secure)
+
 				testKubeAPIServerWasCalled = true
 				testKubeAPIServerSawHeaders = r.Header
 				if tt.kubeAPIServerStatusCode != http.StatusOK {
@@ -1769,17 +1788,26 @@ func TestImpersonatorHTTPHandler(t *testing.T) {
 				} else {
 					_, _ = w.Write([]byte("successful proxied response"))
 				}
-			})
+			}), tlsserver.RecordTLSHello)
+
 			testKubeAPIServerKubeconfig := rest.Config{
-				Host:            testKubeAPIServerURL,
+				Host:            testKubeAPIServer.URL,
 				BearerToken:     "some-service-account-token",
-				TLSClientConfig: rest.TLSClientConfig{CAData: []byte(testKubeAPIServerCA)},
+				TLSClientConfig: rest.TLSClientConfig{CAData: tlsserver.TLSTestServerCA(testKubeAPIServer)},
 			}
 			if tt.restConfig == nil {
 				tt.restConfig = &testKubeAPIServerKubeconfig
 			}
 
-			impersonatorHTTPHandlerFunc, err := newImpersonationReverseProxyFunc(tt.restConfig)
+			// mimic how newInternal would call newImpersonationReverseProxyFunc
+			impersonatorHTTPHandlerFunc, err := func() (func(*genericapiserver.Config) http.Handler, error) {
+				kubeClientForProxy, err := kubeclient.New(kubeclient.WithConfig(tt.restConfig))
+				if err != nil {
+					return nil, err
+				}
+				return newImpersonationReverseProxyFunc(rest.CopyConfig(kubeClientForProxy.ProtoConfig))
+			}()
+
 			if tt.wantCreationErr != "" {
 				require.EqualError(t, err, tt.wantCreationErr)
 				require.Nil(t, impersonatorHTTPHandlerFunc)

internal/concierge/server/server.go

@@ -29,10 +29,12 @@ import (
 	"go.pinniped.dev/internal/controller/authenticator/authncache"
 	"go.pinniped.dev/internal/controllerinit"
 	"go.pinniped.dev/internal/controllermanager"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/downward"
 	"go.pinniped.dev/internal/dynamiccert"
 	"go.pinniped.dev/internal/here"
 	"go.pinniped.dev/internal/issuer"
+	"go.pinniped.dev/internal/kubeclient"
 	"go.pinniped.dev/internal/plog"
 	"go.pinniped.dev/internal/registry/credentialrequest"
 )
@@ -209,6 +211,13 @@ func getAggregatedAPIServerConfig(
 	recommendedOptions.SecureServing.ServerCert.GeneratedCert = dynamicCertProvider
 	recommendedOptions.SecureServing.BindPort = 8443 // Don't run on default 443 because that requires root
 
+	// secure TLS for connections coming from and going to the Kube API server
+	// this is best effort because not all options provide the right hooks to override TLS config
+	// since our only client is the Kube API server, this uses the most secure TLS config
+	if err := ptls.SecureRecommendedOptions(recommendedOptions, kubeclient.Secure); err != nil {
+		return nil, fmt.Errorf("failed to secure recommended options: %w", err)
+	}
+
 	serverConfig := genericapiserver.NewRecommendedConfig(codecs)
 	// Note that among other things, this ApplyTo() function copies
 	// `recommendedOptions.SecureServing.ServerCert.GeneratedCert` into
@@ -220,7 +229,7 @@ func getAggregatedAPIServerConfig(
 	// If the provider later starts returning certs, then the API server
 	// will use them to handle the incoming requests successfully.
 	if err := recommendedOptions.ApplyTo(serverConfig); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to apply recommended options: %w", err)
 	}
 
 	apiServerConfig := &apiserver.Config{

internal/controller/authenticator/authenticator.go

@@ -9,6 +9,8 @@ import (
 	"encoding/base64"
 	"fmt"
 
+	"k8s.io/client-go/util/cert"
+
 	auth1alpha1 "go.pinniped.dev/generated/latest/apis/concierge/authentication/v1alpha1"
 )
 
@@ -23,19 +25,20 @@ type Closer interface {
 // CABundle returns a PEM-encoded CA bundle from the provided spec. If the provided spec is nil, a
 // nil CA bundle will be returned. If the provided spec contains a CA bundle that is not properly
 // encoded, an error will be returned.
-func CABundle(spec *auth1alpha1.TLSSpec) ([]byte, error) {
+func CABundle(spec *auth1alpha1.TLSSpec) (*x509.CertPool, []byte, error) {
 	if spec == nil || len(spec.CertificateAuthorityData) == 0 {
-		return nil, nil
+		return nil, nil, nil
 	}
 
 	pem, err := base64.StdEncoding.DecodeString(spec.CertificateAuthorityData)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
-	if ok := x509.NewCertPool().AppendCertsFromPEM(pem); !ok {
+	rootCAs, err := cert.NewPoolFromBytes(pem)
-		return nil, fmt.Errorf("certificateAuthorityData is not valid PEM")
+	if err != nil {
+		return nil, nil, fmt.Errorf("certificateAuthorityData is not valid PEM: %w", err)
 	}
 
-	return pem, nil
+	return rootCAs, pem, nil
 }

internal/controller/authenticator/jwtcachefiller/jwtcachefiller.go

@@ -6,9 +6,13 @@
 package jwtcachefiller
 
 import (
+	"context"
 	"fmt"
+	"net/url"
 	"reflect"
+	"time"
 
+	coreosoidc "github.com/coreos/go-oidc/v3/oidc"
 	"github.com/go-logr/logr"
 	"gopkg.in/square/go-jose.v2"
 	"k8s.io/apimachinery/pkg/api/errors"
@@ -23,6 +27,7 @@ import (
 	pinnipedauthenticator "go.pinniped.dev/internal/controller/authenticator"
 	"go.pinniped.dev/internal/controller/authenticator/authncache"
 	"go.pinniped.dev/internal/controllerlib"
+	"go.pinniped.dev/internal/net/phttp"
 )
 
 // These default values come from the way that the Supervisor issues and signs tokens. We make these
@@ -145,7 +150,7 @@ func (c *controller) extractValueAsJWTAuthenticator(value authncache.Value) *jwt
 
 // newJWTAuthenticator creates a jwt authenticator from the provided spec.
 func newJWTAuthenticator(spec *auth1alpha1.JWTAuthenticatorSpec) (*jwtAuthenticator, error) {
-	caBundle, err := pinnipedauthenticator.CABundle(spec.TLS)
+	rootCAs, caBundle, err := pinnipedauthenticator.CABundle(spec.TLS)
 	if err != nil {
 		return nil, fmt.Errorf("invalid TLS configuration: %w", err)
 	}
@@ -167,12 +172,43 @@ func newJWTAuthenticator(spec *auth1alpha1.JWTAuthenticatorSpec) (*jwtAuthentica
 		groupsClaim = defaultGroupsClaim
 	}
 
-	authenticator, err := oidc.New(oidc.Options{
+	// copied from Kube OIDC code
+	issuerURL, err := url.Parse(spec.Issuer)
+	if err != nil {
+		return nil, err
+	}
+	if issuerURL.Scheme != "https" {
+		return nil, fmt.Errorf("issuer (%q) has invalid scheme (%q), require 'https'", spec.Issuer, issuerURL.Scheme)
+	}
+
+	client := phttp.Default(rootCAs)
+	client.Timeout = 30 * time.Second // copied from Kube OIDC code
+
+	ctx := coreosoidc.ClientContext(context.Background(), client)
+
+	provider, err := coreosoidc.NewProvider(ctx, spec.Issuer)
+	if err != nil {
+		return nil, fmt.Errorf("could not initialize provider: %w", err)
+	}
+	providerJSON := &struct {
+		JWKSURL string `json:"jwks_uri"`
+	}{}
+	if err := provider.Claims(providerJSON); err != nil {
+		return nil, fmt.Errorf("could not get provider jwks_uri: %w", err) // should be impossible because coreosoidc.NewProvider validates this
+	}
+	if len(providerJSON.JWKSURL) == 0 {
+		return nil, fmt.Errorf("issuer %q does not have jwks_uri set", spec.Issuer)
+	}
+
+	oidcAuthenticator, err := oidc.New(oidc.Options{
 		IssuerURL:            spec.Issuer,
+		KeySet:               coreosoidc.NewRemoteKeySet(ctx, providerJSON.JWKSURL),
 		ClientID:             spec.Audience,
 		UsernameClaim:        usernameClaim,
 		GroupsClaim:          groupsClaim,
 		SupportedSigningAlgs: defaultSupportedSigningAlgos(),
+		// this is still needed for distributed claim resolution, meaning this uses a http client that does not honor our TLS config
+		// TODO fix when we pick up https://github.com/kubernetes/kubernetes/pull/106141
 		CAContentProvider: caContentProvider,
 	})
 	if err != nil {
@@ -180,7 +216,7 @@ func newJWTAuthenticator(spec *auth1alpha1.JWTAuthenticatorSpec) (*jwtAuthentica
 	}
 
 	return &jwtAuthenticator{
-		tokenAuthenticatorCloser: authenticator,
+		tokenAuthenticatorCloser: oidcAuthenticator,
 		spec:                     spec,
 	}, nil
 }

internal/controller/authenticator/jwtcachefiller/jwtcachefiller_test.go

@@ -15,7 +15,6 @@ import (
 	"encoding/pem"
 	"fmt"
 	"net/http"
-	"net/http/httptest"
 	"strings"
 	"testing"
 	"time"
@@ -35,8 +34,10 @@ import (
 	pinnipedinformers "go.pinniped.dev/generated/latest/client/concierge/informers/externalversions"
 	"go.pinniped.dev/internal/controller/authenticator/authncache"
 	"go.pinniped.dev/internal/controllerlib"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/mocks/mocktokenauthenticatorcloser"
 	"go.pinniped.dev/internal/testutil/testlogger"
+	"go.pinniped.dev/internal/testutil/tlsserver"
 )
 
 func TestController(t *testing.T) {
@@ -57,8 +58,10 @@ func TestController(t *testing.T) {
 	goodRSASigningAlgo := jose.RS256
 
 	mux := http.NewServeMux()
-	server := httptest.NewTLSServer(mux)
+	server := tlsserver.TLSTestServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-	t.Cleanup(server.Close)
+		tlsserver.AssertTLS(t, r, ptls.Default)
+		mux.ServeHTTP(w, r)
+	}), tlsserver.RecordTLSHello)
 
 	mux.Handle("/.well-known/openid-configuration", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
@@ -290,11 +293,7 @@ func TestController(t *testing.T) {
 					Spec: *missingTLSJWTAuthenticatorSpec,
 				},
 			},
-			wantLogs: []string{
+			wantErr: `failed to build jwt authenticator: could not initialize provider: Get "` + goodIssuer + `/.well-known/openid-configuration": x509: certificate signed by unknown authority`,
-				`jwtcachefiller-controller "level"=0 "msg"="added new jwt authenticator" "issuer"="` + goodIssuer + `" "jwtAuthenticator"={"name":"test-name"}`,
-			},
-			wantCacheEntries:                 1,
-			runTestsOnResultingAuthenticator: false, // skip the tests because the authenticator left in the cache doesn't have the CA for our test discovery server
 		},
 		{
 			name:    "invalid jwt authenticator CA",

internal/controller/authenticator/webhookcachefiller/webhookcachefiller.go

@@ -91,7 +91,7 @@ func newWebhookAuthenticator(
 	defer func() { _ = os.Remove(temp.Name()) }()
 
 	cluster := &clientcmdapi.Cluster{Server: spec.Endpoint}
-	cluster.CertificateAuthorityData, err = pinnipedauthenticator.CABundle(spec.TLS)
+	_, cluster.CertificateAuthorityData, err = pinnipedauthenticator.CABundle(spec.TLS)
 	if err != nil {
 		return nil, fmt.Errorf("invalid TLS configuration: %w", err)
 	}
@@ -118,5 +118,7 @@ func newWebhookAuthenticator(
 	// custom proxy stuff used by the API server.
 	var customDial net.DialFunc
 
+	// this uses a http client that does not honor our TLS config
+	// TODO fix when we pick up https://github.com/kubernetes/kubernetes/pull/106155
 	return webhook.New(temp.Name(), version, implicitAuds, *webhook.DefaultRetryBackoff(), customDial)
 }

internal/controller/authenticator/webhookcachefiller/webhookcachefiller_test.go

@@ -141,7 +141,7 @@ func TestNewWebhookAuthenticator(t *testing.T) {
 			TLS:      &auth1alpha1.TLSSpec{CertificateAuthorityData: base64.StdEncoding.EncodeToString([]byte("bad data"))},
 		}, ioutil.TempFile, clientcmd.WriteToFile)
 		require.Nil(t, res)
-		require.EqualError(t, err, "invalid TLS configuration: certificateAuthorityData is not valid PEM")
+		require.EqualError(t, err, "invalid TLS configuration: certificateAuthorityData is not valid PEM: data does not contain any valid RSA or ECDSA certificates")
 	})
 
 	t.Run("valid config with no TLS spec", func(t *testing.T) {

internal/controller/kubecertagent/pod_command_executor.go

@@ -26,6 +26,8 @@ type kubeClientPodCommandExecutor struct {
 // NewPodCommandExecutor returns a PodCommandExecutor that will interact with a pod via the provided
 // kubeConfig and corresponding kubeClient.
 func NewPodCommandExecutor(kubeConfig *restclient.Config, kubeClient kubernetes.Interface) PodCommandExecutor {
+	kubeConfig = restclient.CopyConfig(kubeConfig)
+	kubeConfig.NextProtos = []string{"http/1.1"} // we explicitly need to upgrade from http1 to spdy, exec cannot use http2
 	return &kubeClientPodCommandExecutor{kubeConfig: kubeConfig, kubeClient: kubeClient}
 }
 

internal/controller/kubecertagent/pod_command_executor_test.go

@@ -0,0 +1,44 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package kubecertagent
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/client-go/rest"
+
+	"go.pinniped.dev/internal/crypto/ptls"
+	"go.pinniped.dev/internal/kubeclient"
+	"go.pinniped.dev/internal/testutil/tlsserver"
+)
+
+func TestSecureTLS(t *testing.T) {
+	var sawRequest bool
+	server := tlsserver.TLSTestServer(t, http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+		tlsserver.AssertTLS(t, r, ptls.Secure)
+		sawRequest = true
+	}), tlsserver.RecordTLSHello)
+
+	config := &rest.Config{
+		Host: server.URL,
+		TLSClientConfig: rest.TLSClientConfig{
+			CAData: tlsserver.TLSTestServerCA(server),
+		},
+	}
+
+	client, err := kubeclient.New(kubeclient.WithConfig(config))
+	require.NoError(t, err)
+
+	// build this exactly like our production could does
+	podCommandExecutor := NewPodCommandExecutor(client.JSONConfig, client.Kubernetes)
+
+	got, err := podCommandExecutor.Exec("podNamespace", "podName", "command", "arg1", "arg2")
+	require.Equal(t, &errors.StatusError{}, err)
+	require.Empty(t, got)
+
+	require.True(t, sawRequest)
+}

internal/controller/supervisorconfig/oidcupstreamwatcher/oidc_upstream_watcher.go

@@ -6,7 +6,6 @@ package oidcupstreamwatcher
 
 import (
 	"context"
-	"crypto/tls"
 	"crypto/x509"
 	"encoding/base64"
 	"fmt"
@@ -35,6 +34,7 @@ import (
 	"go.pinniped.dev/internal/controller/conditionsutil"
 	"go.pinniped.dev/internal/controller/supervisorconfig/upstreamwatchers"
 	"go.pinniped.dev/internal/controllerlib"
+	"go.pinniped.dev/internal/net/phttp"
 	"go.pinniped.dev/internal/oidc/provider"
 	"go.pinniped.dev/internal/upstreamoidc"
 )
@@ -313,7 +313,8 @@ func (c *oidcWatcherController) validateIssuer(ctx context.Context, upstream *v1
 
 	// If the provider does not exist in the cache, do a fresh discovery lookup and save to the cache.
 	if discoveredProvider == nil {
-		tlsConfig, err := getTLSConfig(upstream)
+		var err error
+		httpClient, err = getClient(upstream)
 		if err != nil {
 			return &v1alpha1.Condition{
 				Type:    typeOIDCDiscoverySucceeded,
@@ -323,14 +324,6 @@ func (c *oidcWatcherController) validateIssuer(ctx context.Context, upstream *v1
 			}
 		}
 
-		httpClient = &http.Client{
-			Timeout: time.Minute,
-			Transport: &http.Transport{
-				Proxy:           http.ProxyFromEnvironment,
-				TLSClientConfig: tlsConfig,
-			},
-		}
-
 		discoveredProvider, err = oidc.NewProvider(oidc.ClientContext(ctx, httpClient), upstream.Spec.Issuer)
 		if err != nil {
 			const klogLevelTrace = 6
@@ -444,13 +437,9 @@ func (c *oidcWatcherController) updateStatus(ctx context.Context, upstream *v1al
 	}
 }
 
-func getTLSConfig(upstream *v1alpha1.OIDCIdentityProvider) (*tls.Config, error) {
+func getClient(upstream *v1alpha1.OIDCIdentityProvider) (*http.Client, error) {
-	result := tls.Config{
-		MinVersion: tls.VersionTLS12,
-	}
-
 	if upstream.Spec.TLS == nil || upstream.Spec.TLS.CertificateAuthorityData == "" {
-		return &result, nil
+		return defaultClientShortTimeout(nil), nil
 	}
 
 	bundle, err := base64.StdEncoding.DecodeString(upstream.Spec.TLS.CertificateAuthorityData)
@@ -458,12 +447,18 @@ func getTLSConfig(upstream *v1alpha1.OIDCIdentityProvider) (*tls.Config, error)
 		return nil, fmt.Errorf("spec.certificateAuthorityData is invalid: %w", err)
 	}
 
-	result.RootCAs = x509.NewCertPool()
+	rootCAs := x509.NewCertPool()
-	if !result.RootCAs.AppendCertsFromPEM(bundle) {
+	if !rootCAs.AppendCertsFromPEM(bundle) {
 		return nil, fmt.Errorf("spec.certificateAuthorityData is invalid: %w", upstreamwatchers.ErrNoCertificates)
 	}
 
-	return &result, nil
+	return defaultClientShortTimeout(rootCAs), nil
+}
+
+func defaultClientShortTimeout(rootCAs *x509.CertPool) *http.Client {
+	c := phttp.Default(rootCAs)
+	c.Timeout = time.Minute
+	return c
 }
 
 func computeScopes(additionalScopes []string) []string {

internal/controller/supervisorconfig/oidcupstreamwatcher/oidc_upstream_watcher_test.go

@@ -19,6 +19,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/net"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes/fake"
 
@@ -1170,8 +1171,7 @@ oidc: issuer did not match the issuer returned by provider, expected "` + testIs
 
 				// We always want to use the proxy from env on these clients, so although the following assertions
 				// are a little hacky, this is a cheap way to test that we are using it.
-				actualTransport, ok := actualIDP.Client.Transport.(*http.Transport)
+				actualTransport := unwrapTransport(t, actualIDP.Client.Transport)
-				require.True(t, ok, "expected cached provider to have client with Transport of type *http.Transport")
 				httpProxyFromEnvFunction := reflect.ValueOf(http.ProxyFromEnvironment).Pointer()
 				actualTransportProxyFunction := reflect.ValueOf(actualTransport.Proxy).Pointer()
 				require.Equal(t, httpProxyFromEnvFunction, actualTransportProxyFunction,
@@ -1197,6 +1197,22 @@ oidc: issuer did not match the issuer returned by provider, expected "` + testIs
 	}
 }
 
+func unwrapTransport(t *testing.T, rt http.RoundTripper) *http.Transport {
+	t.Helper()
+
+	switch baseRT := rt.(type) {
+	case *http.Transport:
+		return baseRT
+
+	case net.RoundTripperWrapper:
+		return unwrapTransport(t, baseRT.WrappedRoundTripper())
+
+	default:
+		t.Fatalf("expected cached provider to have client with Transport of type *http.Transport, got: %T", baseRT)
+		return nil // unreachable
+	}
+}
+
 func normalizeOIDCUpstreams(upstreams []v1alpha1.OIDCIdentityProvider, now metav1.Time) []v1alpha1.OIDCIdentityProvider {
 	result := make([]v1alpha1.OIDCIdentityProvider, 0, len(upstreams))
 	for _, u := range upstreams {

internal/crypto/ptls/old.go

@@ -0,0 +1,15 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build !go1.17
+// +build !go1.17
+
+package ptls
+
+func init() {
+	// cause compile time failure if an older version of Go is used
+	`Pinniped's TLS configuration makes assumptions about how the Go standard library implementation of TLS works.
+It particular, we rely on the server controlling cipher suite selection.  For these assumptions to hold, Pinniped
+must be compiled with Go 1.17+.  If you are seeing this error message, your attempt to compile Pinniped with an
+older Go compiler was explicitly failed to prevent an unsafe configuration.`
+}

internal/crypto/ptls/ptls.go

@@ -0,0 +1,215 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package ptls
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"net/http"
+	"sync"
+
+	"k8s.io/apiserver/pkg/admission"
+	genericapiserver "k8s.io/apiserver/pkg/server"
+	"k8s.io/apiserver/pkg/server/options"
+	kubeinformers "k8s.io/client-go/informers"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
+	"k8s.io/client-go/transport"
+)
+
+// TODO decide if we need to expose the four TLS levels (secure, default, default-ldap, legacy) as config.
+
+type ConfigFunc func(*x509.CertPool) *tls.Config
+
+func Default(rootCAs *x509.CertPool) *tls.Config {
+	return &tls.Config{
+		// Can't use SSLv3 because of POODLE and BEAST
+		// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
+		// Can't use TLSv1.1 because of RC4 cipher usage
+		//
+		// The Kubernetes API Server must use TLS 1.2, at a minimum,
+		// to protect the confidentiality of sensitive data during electronic dissemination.
+		// https://stigviewer.com/stig/kubernetes/2021-06-17/finding/V-242378
+		MinVersion: tls.VersionTLS12,
+
+		// the order does not matter in go 1.17+ https://go.dev/blog/tls-cipher-suites
+		// we match crypto/tls.cipherSuitesPreferenceOrder because it makes unit tests easier to write
+		// this list is ignored when TLS 1.3 is used
+		//
+		// as of 2021-10-19, Mozilla Guideline v5.6, Go 1.17.2, intermediate configuration, supports:
+		// - Firefox 27
+		// - Android 4.4.2
+		// - Chrome 31
+		// - Edge
+		// - IE 11 on Windows 7
+		// - Java 8u31
+		// - OpenSSL 1.0.1
+		// - Opera 20
+		// - Safari 9
+		// https://ssl-config.mozilla.org/#server=go&version=1.17.2&config=intermediate&guideline=5.6
+		//
+		// The Kubernetes API server must use approved cipher suites.
+		// https://stigviewer.com/stig/kubernetes/2021-06-17/finding/V-242418
+		CipherSuites: []uint16{
+			// these are all AEADs with ECDHE, some use ChaCha20Poly1305 while others use AES-GCM
+			// this provides forward secrecy, confidentiality and authenticity of data
+			tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+			tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+			tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+		},
+
+		// enable HTTP2 for go's 1.7 HTTP Server
+		// setting this explicitly is only required in very specific circumstances
+		// it is simpler to just set it here than to try and determine if we need to
+		NextProtos: []string{"h2", "http/1.1"},
+
+		// optional root CAs, nil means use the host's root CA set
+		RootCAs: rootCAs,
+	}
+}
+
+func Secure(rootCAs *x509.CertPool) *tls.Config {
+	// as of 2021-10-19, Mozilla Guideline v5.6, Go 1.17.2, modern configuration, supports:
+	// - Firefox 63
+	// - Android 10.0
+	// - Chrome 70
+	// - Edge 75
+	// - Java 11
+	// - OpenSSL 1.1.1
+	// - Opera 57
+	// - Safari 12.1
+	// https://ssl-config.mozilla.org/#server=go&version=1.17.2&config=modern&guideline=5.6
+	c := Default(rootCAs)
+	c.MinVersion = tls.VersionTLS13 // max out the security
+	c.CipherSuites = []uint16{
+		// TLS 1.3 ciphers are not configurable, but we need to explicitly set them here to make our client hello behave correctly
+		// See https://github.com/golang/go/pull/49293
+		tls.TLS_AES_128_GCM_SHA256,
+		tls.TLS_AES_256_GCM_SHA384,
+		tls.TLS_CHACHA20_POLY1305_SHA256,
+	}
+	return c
+}
+
+func DefaultLDAP(rootCAs *x509.CertPool) *tls.Config {
+	c := Default(rootCAs)
+	// add less secure ciphers to support the default AWS Active Directory config
+	c.CipherSuites = append(c.CipherSuites,
+		// CBC with ECDHE
+		// this provides forward secrecy and confidentiality of data but not authenticity
+		// MAC-then-Encrypt CBC ciphers are susceptible to padding oracle attacks
+		// See https://crypto.stackexchange.com/a/205 and https://crypto.stackexchange.com/a/224
+		tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+		tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+	)
+	return c
+}
+
+func Legacy(rootCAs *x509.CertPool) *tls.Config {
+	c := Default(rootCAs)
+	// add all the ciphers (even the crappy ones) except the ones that Go considers to be outright broken like 3DES
+	c.CipherSuites = suitesToIDs(tls.CipherSuites())
+	return c
+}
+
+func suitesToIDs(suites []*tls.CipherSuite) []uint16 {
+	out := make([]uint16, 0, len(suites))
+	for _, suite := range suites {
+		suite := suite
+		out = append(out, suite.ID)
+	}
+	return out
+}
+
+func Merge(tlsConfigFunc ConfigFunc, tlsConfig *tls.Config) {
+	secureTLSConfig := tlsConfigFunc(nil)
+
+	// override the core security knobs of the TLS config
+	// note that these have to be kept in sync with Default / Secure above
+	tlsConfig.MinVersion = secureTLSConfig.MinVersion
+	tlsConfig.CipherSuites = secureTLSConfig.CipherSuites
+
+	// if the TLS config already states what protocols it wants to use, honor that instead of overriding
+	if len(tlsConfig.NextProtos) == 0 {
+		tlsConfig.NextProtos = secureTLSConfig.NextProtos
+	}
+}
+
+// RestConfigFunc allows this package to not depend on the kubeclient package.
+type RestConfigFunc func(*rest.Config) (kubernetes.Interface, *rest.Config, error)
+
+func DefaultRecommendedOptions(opts *options.RecommendedOptions, f RestConfigFunc) error {
+	defaultServing(opts.SecureServing)
+	return secureClient(opts, f)
+}
+
+func SecureRecommendedOptions(opts *options.RecommendedOptions, f RestConfigFunc) error {
+	secureServing(opts.SecureServing)
+	return secureClient(opts, f)
+}
+
+func defaultServing(opts *options.SecureServingOptionsWithLoopback) {
+	c := Default(nil)
+	cipherSuites := make([]string, 0, len(c.CipherSuites))
+	for _, id := range c.CipherSuites {
+		cipherSuites = append(cipherSuites, tls.CipherSuiteName(id))
+	}
+	opts.CipherSuites = cipherSuites
+
+	opts.MinTLSVersion = "VersionTLS12"
+}
+
+func secureServing(opts *options.SecureServingOptionsWithLoopback) {
+	opts.MinTLSVersion = "VersionTLS13"
+	opts.CipherSuites = nil
+}
+
+func secureClient(opts *options.RecommendedOptions, f RestConfigFunc) error {
+	inClusterClient, inClusterConfig, err := f(nil)
+	if err != nil {
+		return fmt.Errorf("failed to build in cluster client: %w", err)
+	}
+
+	if n, z := opts.Authentication.RemoteKubeConfigFile, opts.Authorization.RemoteKubeConfigFile; len(n) > 0 || len(z) > 0 {
+		return fmt.Errorf("delgating auth is not using in-cluster config:\nauthentication=%s\nauthorization=%s", n, z)
+	}
+
+	// delegated authn and authz provide easy hooks for us to set the TLS config.
+	// however, the underlying clients use client-go's global TLS cache with an
+	// in-cluster config.  to make this safe, we simply do the mutation once.
+	wrapperFunc := wrapTransportOnce(inClusterConfig.WrapTransport)
+	opts.Authentication.CustomRoundTripperFn = wrapperFunc
+	opts.Authorization.CustomRoundTripperFn = wrapperFunc
+
+	opts.CoreAPI = nil // set this to nil to make sure our ExtraAdmissionInitializers is used
+	baseExtraAdmissionInitializers := opts.ExtraAdmissionInitializers
+	opts.ExtraAdmissionInitializers = func(c *genericapiserver.RecommendedConfig) ([]admission.PluginInitializer, error) {
+		// abuse this closure to rewrite how we load admission plugins
+		c.ClientConfig = inClusterConfig
+		c.SharedInformerFactory = kubeinformers.NewSharedInformerFactory(inClusterClient, 0)
+
+		// abuse this closure to rewrite our loopback config
+		// this is mostly future proofing for post start hooks
+		_, loopbackConfig, err := f(c.LoopbackClientConfig)
+		if err != nil {
+			return nil, fmt.Errorf("failed to build loopback config: %w", err)
+		}
+		c.LoopbackClientConfig = loopbackConfig
+
+		return baseExtraAdmissionInitializers(c)
+	}
+
+	return nil
+}
+
+func wrapTransportOnce(f transport.WrapperFunc) transport.WrapperFunc {
+	var once sync.Once
+	return func(rt http.RoundTripper) http.RoundTripper {
+		once.Do(func() {
+			_ = f(rt) // assume in-place mutation
+		})
+		return rt
+	}
+}

internal/crypto/ptls/ptls_test.go

@@ -0,0 +1,253 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package ptls
+
+import (
+	"crypto/tls"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"k8s.io/apiserver/pkg/server/options"
+)
+
+func TestDefaultServing(t *testing.T) {
+	t.Parallel()
+
+	opts := &options.SecureServingOptionsWithLoopback{SecureServingOptions: &options.SecureServingOptions{}}
+	defaultServing(opts)
+	require.Equal(t, options.SecureServingOptionsWithLoopback{
+		SecureServingOptions: &options.SecureServingOptions{
+			CipherSuites: []string{
+				"TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256",
+				"TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
+				"TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384",
+				"TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384",
+				"TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256",
+				"TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256",
+			},
+			MinTLSVersion: "VersionTLS12",
+		},
+	}, *opts)
+}
+
+func TestSecureServing(t *testing.T) {
+	t.Parallel()
+
+	opts := &options.SecureServingOptionsWithLoopback{SecureServingOptions: &options.SecureServingOptions{}}
+	secureServing(opts)
+	require.Equal(t, options.SecureServingOptionsWithLoopback{
+		SecureServingOptions: &options.SecureServingOptions{
+			MinTLSVersion: "VersionTLS13",
+		},
+	}, *opts)
+}
+
+func TestMerge(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name          string
+		tlsConfigFunc ConfigFunc
+		tlsConfig     *tls.Config
+		want          *tls.Config
+	}{
+		{
+			name:          "default no protos",
+			tlsConfigFunc: Default,
+			tlsConfig: &tls.Config{
+				ServerName: "something-to-check-passthrough",
+			},
+			want: &tls.Config{
+				ServerName: "something-to-check-passthrough",
+				MinVersion: tls.VersionTLS12,
+				CipherSuites: []uint16{
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
+				},
+				NextProtos: []string{"h2", "http/1.1"},
+			},
+		},
+		{
+			name:          "default with protos",
+			tlsConfigFunc: Default,
+			tlsConfig: &tls.Config{
+				ServerName: "a different thing for passthrough",
+				NextProtos: []string{"panda"},
+			},
+			want: &tls.Config{
+				ServerName: "a different thing for passthrough",
+				MinVersion: tls.VersionTLS12,
+				CipherSuites: []uint16{
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
+				},
+				NextProtos: []string{"panda"},
+			},
+		},
+		{
+			name:          "secure no protos",
+			tlsConfigFunc: Secure,
+			tlsConfig: &tls.Config{
+				ServerName: "something-to-check-passthrough",
+			},
+			want: &tls.Config{
+				ServerName: "something-to-check-passthrough",
+				MinVersion: tls.VersionTLS13,
+				CipherSuites: []uint16{
+					tls.TLS_AES_128_GCM_SHA256,
+					tls.TLS_AES_256_GCM_SHA384,
+					tls.TLS_CHACHA20_POLY1305_SHA256,
+				},
+				NextProtos: []string{"h2", "http/1.1"},
+			},
+		},
+		{
+			name:          "secure with protos",
+			tlsConfigFunc: Secure,
+			tlsConfig: &tls.Config{
+				ServerName: "a different thing for passthrough",
+				NextProtos: []string{"panda"},
+			},
+			want: &tls.Config{
+				ServerName: "a different thing for passthrough",
+				MinVersion: tls.VersionTLS13,
+				CipherSuites: []uint16{
+					tls.TLS_AES_128_GCM_SHA256,
+					tls.TLS_AES_256_GCM_SHA384,
+					tls.TLS_CHACHA20_POLY1305_SHA256,
+				},
+				NextProtos: []string{"panda"},
+			},
+		},
+		{
+			name:          "default ldap no protos",
+			tlsConfigFunc: DefaultLDAP,
+			tlsConfig: &tls.Config{
+				ServerName: "something-to-check-passthrough",
+			},
+			want: &tls.Config{
+				ServerName: "something-to-check-passthrough",
+				MinVersion: tls.VersionTLS12,
+				CipherSuites: []uint16{
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, //nolint: gosec  // yeah, I know it is a bad cipher, but AD sucks
+					tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				},
+				NextProtos: []string{"h2", "http/1.1"},
+			},
+		},
+		{
+			name:          "default ldap with protos",
+			tlsConfigFunc: DefaultLDAP,
+			tlsConfig: &tls.Config{
+				ServerName: "a different thing for passthrough",
+				NextProtos: []string{"panda"},
+			},
+			want: &tls.Config{
+				ServerName: "a different thing for passthrough",
+				MinVersion: tls.VersionTLS12,
+				CipherSuites: []uint16{
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, //nolint: gosec  // yeah, I know it is a bad cipher, but AD sucks
+					tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				},
+				NextProtos: []string{"panda"},
+			},
+		},
+		{
+			name:          "legacy no protos",
+			tlsConfigFunc: Legacy,
+			tlsConfig: &tls.Config{
+				ServerName: "something-to-check-passthrough",
+			},
+			want: &tls.Config{
+				ServerName: "something-to-check-passthrough",
+				MinVersion: tls.VersionTLS12,
+				CipherSuites: []uint16{
+					tls.TLS_RSA_WITH_AES_128_CBC_SHA, //nolint: gosec  // yeah, I know it is a bad cipher, this is the legacy config
+					tls.TLS_RSA_WITH_AES_256_CBC_SHA,
+					tls.TLS_RSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_AES_128_GCM_SHA256,
+					tls.TLS_AES_256_GCM_SHA384,
+					tls.TLS_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+					tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
+				},
+				NextProtos: []string{"h2", "http/1.1"},
+			},
+		},
+		{
+			name:          "legacy with protos",
+			tlsConfigFunc: Legacy,
+			tlsConfig: &tls.Config{
+				ServerName: "a different thing for passthrough",
+				NextProtos: []string{"panda"},
+			},
+			want: &tls.Config{
+				ServerName: "a different thing for passthrough",
+				MinVersion: tls.VersionTLS12,
+				CipherSuites: []uint16{
+					tls.TLS_RSA_WITH_AES_128_CBC_SHA, //nolint: gosec  // yeah, I know it is a bad cipher, this is the legacy config
+					tls.TLS_RSA_WITH_AES_256_CBC_SHA,
+					tls.TLS_RSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_AES_128_GCM_SHA256,
+					tls.TLS_AES_256_GCM_SHA384,
+					tls.TLS_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+					tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+					tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+					tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
+					tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
+				},
+				NextProtos: []string{"panda"},
+			},
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			Merge(tt.tlsConfigFunc, tt.tlsConfig)
+			require.Equal(t, tt.want, tt.tlsConfig)
+		})
+	}
+}

internal/dynamiccert/provider_test.go

@@ -19,6 +19,7 @@ import (
 	"k8s.io/apiserver/pkg/storage/names"
 
 	"go.pinniped.dev/internal/certauthority"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/test/testlib"
 )
 
@@ -160,11 +161,8 @@ func TestProviderWithDynamicServingCertificateController(t *testing.T) {
 			err = certKeyContent.SetCertKeyContent(cert, key)
 			require.NoError(t, err)
 
-			tlsConfig := &tls.Config{
+			tlsConfig := ptls.Default(nil)
-				MinVersion: tls.VersionTLS12,
+			tlsConfig.ClientAuth = tls.RequestClientCert
-				NextProtos: []string{"h2", "http/1.1"},
-				ClientAuth: tls.RequestClientCert,
-			}
 
 			dynamicCertificateController := dynamiccertificates.NewDynamicServingCertificateController(
 				tlsConfig,

internal/httputil/roundtripper/roundtripper.go

@@ -3,7 +3,11 @@
 
 package roundtripper
 
-import "net/http"
+import (
+	"net/http"
+
+	"k8s.io/apimachinery/pkg/util/net"
+)
 
 var _ http.RoundTripper = Func(nil)
 
@@ -12,3 +16,22 @@ type Func func(*http.Request) (*http.Response, error)
 func (f Func) RoundTrip(req *http.Request) (*http.Response, error) {
 	return f(req)
 }
+
+var _ net.RoundTripperWrapper = &wrapper{}
+
+type wrapper struct {
+	delegate http.RoundTripper
+	f        Func
+}
+
+func (w *wrapper) RoundTrip(req *http.Request) (*http.Response, error) {
+	return w.f.RoundTrip(req)
+}
+
+func (w *wrapper) WrappedRoundTripper() http.RoundTripper {
+	return w.delegate
+}
+
+func WrapFunc(delegate http.RoundTripper, f Func) net.RoundTripperWrapper {
+	return &wrapper{delegate: delegate, f: f}
+}

internal/kubeclient/kubeclient.go

@@ -4,9 +4,17 @@
 package kubeclient
 
 import (
+	"crypto/tls"
+	"crypto/x509"
 	"fmt"
+	"net/http"
+	"reflect"
+	"unsafe"
 
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/net"
 	"k8s.io/client-go/kubernetes"
 	kubescheme "k8s.io/client-go/kubernetes/scheme"
 	restclient "k8s.io/client-go/rest"
@@ -17,6 +25,7 @@ import (
 	pinnipedconciergeclientsetscheme "go.pinniped.dev/generated/latest/client/concierge/clientset/versioned/scheme"
 	pinnipedsupervisorclientset "go.pinniped.dev/generated/latest/client/supervisor/clientset/versioned"
 	pinnipedsupervisorclientsetscheme "go.pinniped.dev/generated/latest/client/supervisor/clientset/versioned/scheme"
+	"go.pinniped.dev/internal/crypto/ptls"
 )
 
 type Client struct {
@@ -44,11 +53,16 @@ func New(opts ...Option) (*Client, error) {
 		WithConfig(inClusterConfig)(c) // make sure all writes to clientConfig flow through one code path
 	}
 
+	secureKubeConfig, err := createSecureKubeConfig(c.config)
+	if err != nil {
+		return nil, fmt.Errorf("could not create secure client config: %w", err)
+	}
+
 	// explicitly use json when talking to CRD APIs
-	jsonKubeConfig := createJSONKubeConfig(c.config)
+	jsonKubeConfig := createJSONKubeConfig(secureKubeConfig)
 
 	// explicitly use protobuf when talking to built-in kube APIs
-	protoKubeConfig := createProtoKubeConfig(c.config)
+	protoKubeConfig := createProtoKubeConfig(secureKubeConfig)
 
 	// Connect to the core Kubernetes API.
 	k8sClient, err := kubernetes.NewForConfig(configWithWrapper(protoKubeConfig, kubescheme.Scheme, kubescheme.Codecs, c.middlewares, c.transportWrapper))
@@ -107,3 +121,142 @@ func createProtoKubeConfig(kubeConfig *restclient.Config) *restclient.Config {
 	protoKubeConfig.ContentType = runtime.ContentTypeProtobuf
 	return protoKubeConfig
 }
+
+// createSecureKubeConfig returns a copy of the input config with the WrapTransport
+// enhanced to use the secure TLS configuration of the ptls / phttp packages.
+func createSecureKubeConfig(kubeConfig *restclient.Config) (*restclient.Config, error) {
+	secureKubeConfig := restclient.CopyConfig(kubeConfig)
+
+	// by setting proxy to always be non-nil, we bust the client-go global TLS config cache.
+	// this is required to make our wrapper function work without data races.  the unit tests
+	// associated with this code run in parallel to assert that we are not using the cache.
+	// see k8s.io/client-go/transport.tlsConfigKey
+	if secureKubeConfig.Proxy == nil {
+		secureKubeConfig.Proxy = net.NewProxierWithNoProxyCIDR(http.ProxyFromEnvironment)
+	}
+
+	// make sure restclient.TLSConfigFor always returns a non-nil TLS config
+	if len(secureKubeConfig.NextProtos) == 0 {
+		secureKubeConfig.NextProtos = ptls.Secure(nil).NextProtos
+	}
+
+	tlsConfigTest, err := restclient.TLSConfigFor(secureKubeConfig)
+	if err != nil {
+		return nil, err // should never happen because our input config should always be valid
+	}
+	if tlsConfigTest == nil {
+		return nil, fmt.Errorf("unexpected empty TLS config") // should never happen because we set NextProtos above
+	}
+
+	secureKubeConfig.Wrap(func(rt http.RoundTripper) http.RoundTripper {
+		defer func() {
+			if err := AssertSecureTransport(rt); err != nil {
+				panic(err) // not sure what the point of this function would be if it failed to make the config secure
+			}
+		}()
+
+		tlsConfig, err := netTLSClientConfig(rt)
+		if err != nil {
+			// this assumes none of our production code calls Wrap or messes with WrapTransport.
+			// this is a reasonable assumption because all such code should live in this package
+			// and all such code should run after this function is called, not before.  the kube
+			// codebase uses transport wrappers that can be unwrapped to access the underlying
+			// TLS config.
+			panic(err)
+		}
+		if tlsConfig == nil {
+			panic("unexpected empty TLS config") // we validate this case above via tlsConfigTest
+		}
+
+		// mutate the TLS config into our desired state before it is used
+		ptls.Merge(ptls.Secure, tlsConfig)
+
+		return rt // return the input transport since we mutated it in-place
+	})
+
+	if err := AssertSecureConfig(secureKubeConfig); err != nil {
+		return nil, err // not sure what the point of this function would be if it failed to make the config secure
+	}
+
+	return secureKubeConfig, nil
+}
+
+// SecureAnonymousClientConfig has the same properties as restclient.AnonymousClientConfig
+// while still enforcing the secure TLS configuration of the ptls / phttp packages.
+func SecureAnonymousClientConfig(kubeConfig *restclient.Config) *restclient.Config {
+	kubeConfig = restclient.AnonymousClientConfig(kubeConfig)
+	secureKubeConfig, err := createSecureKubeConfig(kubeConfig)
+	if err != nil {
+		panic(err) // should never happen as this would only fail on invalid CA data, which would never work anyway
+	}
+	if err := AssertSecureConfig(secureKubeConfig); err != nil {
+		panic(err) // not sure what the point of this function would be if it failed to make the config secure
+	}
+	return secureKubeConfig
+}
+
+func AssertSecureConfig(kubeConfig *restclient.Config) error {
+	rt, err := restclient.TransportFor(kubeConfig)
+	if err != nil {
+		return fmt.Errorf("failed to build transport: %w", err)
+	}
+
+	return AssertSecureTransport(rt)
+}
+
+func AssertSecureTransport(rt http.RoundTripper) error {
+	tlsConfig, err := netTLSClientConfig(rt)
+	if err != nil {
+		return fmt.Errorf("failed to get TLS config: %w", err)
+	}
+
+	tlsConfigCopy := tlsConfig.Clone()
+	ptls.Merge(ptls.Secure, tlsConfigCopy) // only mutate the copy
+
+	//nolint: gosec // the empty TLS config here is not used
+	if diff := cmp.Diff(tlsConfigCopy, tlsConfig,
+		cmpopts.IgnoreUnexported(tls.Config{}, x509.CertPool{}),
+		cmpopts.IgnoreFields(tls.Config{}, "GetClientCertificate"),
+	); len(diff) != 0 {
+		return fmt.Errorf("tls config is not secure:\n%s", diff)
+	}
+
+	return nil
+}
+
+func netTLSClientConfig(rt http.RoundTripper) (*tls.Config, error) {
+	tlsConfig, err := net.TLSClientConfig(rt)
+	if err == nil {
+		return tlsConfig, nil
+	}
+
+	// TODO fix when we pick up https://github.com/kubernetes/kubernetes/pull/106014
+	if err.Error() == "unknown transport type: *exec.roundTripper" {
+		return net.TLSClientConfig(extractRTUnsafe(rt))
+	}
+
+	return nil, err
+}
+
+func extractRTUnsafe(rt http.RoundTripper) (out http.RoundTripper) {
+	for wrapper, ok := rt.(net.RoundTripperWrapper); ok; wrapper, ok = rt.(net.RoundTripperWrapper) {
+		// keep peeling the wrappers until we get to the exec.roundTripper
+		rt = wrapper.WrappedRoundTripper()
+	}
+
+	// this is some dark magic to read a private field
+	baseField := reflect.ValueOf(rt).Elem().FieldByName("base")
+	basePointer := (*http.RoundTripper)(unsafe.Pointer(baseField.UnsafeAddr()))
+
+	return *basePointer
+}
+
+func Secure(config *restclient.Config) (kubernetes.Interface, *restclient.Config, error) {
+	// our middleware does not apply to the returned restclient.Config, therefore, this
+	// client not having a leader election lock is irrelevant since it would not be enforced
+	secureClient, err := New(WithConfig(config)) // handles nil config correctly
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to build secure client: %w", err)
+	}
+	return secureClient.Kubernetes, secureClient.ProtoConfig, nil
+}

internal/kubeclient/kubeclient_test.go

@@ -7,22 +7,31 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"net"
 	"net/http"
+	"net/url"
 	"runtime"
 	"strings"
+	"sync"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	clientauthenticationv1 "k8s.io/client-go/pkg/apis/clientauthentication/v1"
 	"k8s.io/client-go/rest"
+	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
 	"k8s.io/client-go/transport"
 	apiregistrationv1 "k8s.io/kube-aggregator/pkg/apis/apiregistration/v1"
 
+	// register all client-go auth plugins.
+	_ "k8s.io/client-go/plugin/pkg/client/auth"
+
 	conciergeconfigv1alpha1 "go.pinniped.dev/generated/latest/apis/concierge/config/v1alpha1"
 	supervisorconfigv1alpha1 "go.pinniped.dev/generated/latest/apis/supervisor/config/v1alpha1"
+	"go.pinniped.dev/internal/crypto/ptls"
+	"go.pinniped.dev/internal/httputil/roundtripper"
 	"go.pinniped.dev/internal/testutil/fakekubeapi"
 )
 
@@ -514,9 +523,12 @@ func TestKubeclient(t *testing.T) {
 				return []*spyMiddleware{newSimpleMiddleware(t, true, false, false)}
 			},
 			editRestConfig: func(t *testing.T, restConfig *rest.Config) {
-				restConfig.Dial = func(_ context.Context, _, _ string) (net.Conn, error) {
+				// avoid messing with restConfig.Dial since it breaks client-go TLS cache logic
+				restConfig.Wrap(func(rt http.RoundTripper) http.RoundTripper {
+					return roundtripper.WrapFunc(rt, func(_ *http.Request) (*http.Response, error) {
 						return nil, fmt.Errorf("some fake connection error")
-				}
+					})
+				})
 			},
 			reallyRunTest: func(t *testing.T, c *Client) {
 				_, err := c.PinnipedSupervisor.
@@ -591,8 +603,7 @@ func TestKubeclient(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(test.name, func(t *testing.T) {
-			server, restConfig := fakekubeapi.Start(t, nil)
+			_, restConfig := fakekubeapi.Start(t, nil)
-			defer server.Close()
 
 			if test.editRestConfig != nil {
 				test.editRestConfig(t, restConfig)
@@ -754,21 +765,45 @@ func newFailingMiddleware(t *testing.T, name string, mutateReqFails, mutateRespF
 }
 
 type wantCloser struct {
-	io.ReadCloser
+	m sync.Mutex
-	closeCount                      int
+
-	closeCalls                      []string
+	_rc                              io.ReadCloser
-	couldReadBytesJustBeforeClosing bool
+	_closeCalls                      []string
+	_couldReadBytesJustBeforeClosing bool
 }
 
-func (wc *wantCloser) Close() error {
+func (w *wantCloser) Close() error {
-	wc.closeCount++
+	w.m.Lock()
-	wc.closeCalls = append(wc.closeCalls, getCaller())
+	defer w.m.Unlock()
-	n, _ := wc.ReadCloser.Read([]byte{0})
+
+	w._closeCalls = append(w._closeCalls, getCaller())
+	n, _ := w._rc.Read([]byte{0})
 	if n > 0 {
 		// there were still bytes left to be read
-		wc.couldReadBytesJustBeforeClosing = true
+		w._couldReadBytesJustBeforeClosing = true
 	}
-	return wc.ReadCloser.Close()
+	return w._rc.Close()
+}
+
+func (w *wantCloser) Read(p []byte) (int, error) {
+	w.m.Lock()
+	defer w.m.Unlock()
+
+	return w._rc.Read(p)
+}
+
+func (w *wantCloser) couldRead() bool {
+	w.m.Lock()
+	defer w.m.Unlock()
+
+	return w._couldReadBytesJustBeforeClosing
+}
+
+func (w *wantCloser) calls() []string {
+	w.m.Lock()
+	defer w.m.Unlock()
+
+	return w._closeCalls
 }
 
 func getCaller() string {
@@ -785,11 +820,14 @@ func getCaller() string {
 func wantCloseReqWrapper(t *testing.T) transport.WrapperFunc {
 	caller := getCaller()
 	return func(rt http.RoundTripper) http.RoundTripper {
-		return roundTripperFunc(func(req *http.Request) (bool, *http.Response, error) {
+		return roundtripper.WrapFunc(rt, roundTripperFunc(func(req *http.Request) (bool, *http.Response, error) {
 			if req.Body != nil {
-				wc := &wantCloser{ReadCloser: req.Body}
+				wc := &wantCloser{_rc: req.Body}
 				t.Cleanup(func() {
-					require.Equalf(t, wc.closeCount, 1, "did not close req body expected number of times at %s for req %#v; actual calls = %s", caller, req, wc.closeCalls)
+					require.Eventuallyf(t, func() bool {
+						return 1 == len(wc.calls())
+					}, 5*time.Second, 100*time.Millisecond,
+						"did not close req body expected number of times at %s for req %#v; actual calls = %s", caller, req, wc.calls())
 				})
 				req.Body = wc
 			}
@@ -800,9 +838,12 @@ func wantCloseReqWrapper(t *testing.T) transport.WrapperFunc {
 					if originalErr != nil {
 						return nil, originalErr
 					}
-					wc := &wantCloser{ReadCloser: originalBodyCopy}
+					wc := &wantCloser{_rc: originalBodyCopy}
 					t.Cleanup(func() {
-						require.Equalf(t, wc.closeCount, 1, "did not close req body copy expected number of times at %s for req %#v; actual calls = %s", caller, req, wc.closeCalls)
+						require.Eventuallyf(t, func() bool {
+							return 1 == len(wc.calls())
+						}, 5*time.Second, 100*time.Millisecond,
+							"did not close req body copy expected number of times at %s for req %#v; actual calls = %s", caller, req, wc.calls())
 					})
 					return wc, nil
 				}
@@ -810,7 +851,7 @@ func wantCloseReqWrapper(t *testing.T) transport.WrapperFunc {
 
 			resp, err := rt.RoundTrip(req)
 			return false, resp, err
-		})
+		}).RoundTrip)
 	}
 }
 
@@ -819,20 +860,24 @@ func wantCloseReqWrapper(t *testing.T) transport.WrapperFunc {
 func wantCloseRespWrapper(t *testing.T) transport.WrapperFunc {
 	caller := getCaller()
 	return func(rt http.RoundTripper) http.RoundTripper {
-		return roundTripperFunc(func(req *http.Request) (bool, *http.Response, error) {
+		return roundtripper.WrapFunc(rt, roundTripperFunc(func(req *http.Request) (bool, *http.Response, error) {
 			resp, err := rt.RoundTrip(req)
 			if err != nil {
 				// request failed, so there is no response body to watch for Close() calls on
 				return false, resp, err
 			}
-			wc := &wantCloser{ReadCloser: resp.Body}
+			wc := &wantCloser{_rc: resp.Body}
 			t.Cleanup(func() {
-				require.False(t, wc.couldReadBytesJustBeforeClosing, "did not consume all response body bytes before closing %s", caller)
+				require.Eventuallyf(t, func() bool {
-				require.Equalf(t, wc.closeCount, 1, "did not close resp body expected number of times at %s for req %#v; actual calls = %s", caller, req, wc.closeCalls)
+					return wc.couldRead() == false &&
+						1 == len(wc.calls())
+				}, 5*time.Second, 10*time.Millisecond,
+					`did not close resp body expected number of times at %s for req %#v; actual calls = %s
+did not consume all response body bytes before closing %s, couldRead=%v`, caller, req, wc.calls(), caller, wc.couldRead())
 			})
 			resp.Body = wc
 			return false, resp, err
-		})
+		}).RoundTrip)
 	}
 }
 
@@ -895,3 +940,221 @@ func createGetFederationDomainTest(t *testing.T, client *Client) {
 	require.NoError(t, err)
 	require.Equal(t, goodFederationDomain, federationDomain)
 }
+
+// TestUnwrap ensures that the Client struct returned by this package only contains
+// transports that can be fully unwrapped to get access to the underlying TLS config.
+func TestUnwrap(t *testing.T) {
+	t.Parallel() // make sure to run in parallel to confirm that our client-go TLS cache busting works (i.e. assert no data races)
+
+	server, restConfig := fakekubeapi.Start(t, nil)
+
+	serverSubjects := server.Client().Transport.(*http.Transport).TLSClientConfig.RootCAs.Subjects()
+
+	t.Run("regular client", func(t *testing.T) {
+		t.Parallel() // make sure to run in parallel to confirm that our client-go TLS cache busting works (i.e. assert no data races)
+
+		regularClient := makeClient(t, restConfig, func(_ *rest.Config) {})
+
+		testUnwrap(t, regularClient, serverSubjects)
+	})
+
+	t.Run("exec client", func(t *testing.T) {
+		t.Parallel() // make sure to run in parallel to confirm that our client-go TLS cache busting works (i.e. assert no data races)
+
+		execClient := makeClient(t, restConfig, func(config *rest.Config) {
+			config.ExecProvider = &clientcmdapi.ExecConfig{
+				Command:         "echo",
+				Args:            []string{"pandas are awesome"},
+				APIVersion:      clientauthenticationv1.SchemeGroupVersion.String(),
+				InteractiveMode: clientcmdapi.NeverExecInteractiveMode,
+			}
+		})
+
+		testUnwrap(t, execClient, serverSubjects)
+	})
+
+	t.Run("gcp client", func(t *testing.T) {
+		t.Parallel() // make sure to run in parallel to confirm that our client-go TLS cache busting works (i.e. assert no data races)
+
+		gcpClient := makeClient(t, restConfig, func(config *rest.Config) {
+			config.AuthProvider = &clientcmdapi.AuthProviderConfig{
+				Name: "gcp",
+			}
+		})
+
+		testUnwrap(t, gcpClient, serverSubjects)
+	})
+
+	t.Run("oidc client", func(t *testing.T) {
+		t.Parallel() // make sure to run in parallel to confirm that our client-go TLS cache busting works (i.e. assert no data races)
+
+		oidcClient := makeClient(t, restConfig, func(config *rest.Config) {
+			config.AuthProvider = &clientcmdapi.AuthProviderConfig{
+				Name: "oidc",
+				Config: map[string]string{
+					"idp-issuer-url": "https://pandas.local",
+					"client-id":      "walrus",
+				},
+			}
+		})
+
+		testUnwrap(t, oidcClient, serverSubjects)
+	})
+
+	t.Run("azure client", func(t *testing.T) {
+		t.Parallel() // make sure to run in parallel to confirm that our client-go TLS cache busting works (i.e. assert no data races)
+
+		azureClient := makeClient(t, restConfig, func(config *rest.Config) {
+			config.AuthProvider = &clientcmdapi.AuthProviderConfig{
+				Name: "azure",
+				Config: map[string]string{
+					"client-id":    "pinny",
+					"tenant-id":    "danger",
+					"apiserver-id": "1234",
+				},
+			}
+		})
+
+		testUnwrap(t, azureClient, serverSubjects)
+	})
+}
+
+func testUnwrap(t *testing.T, client *Client, serverSubjects [][]byte) {
+	tests := []struct {
+		name string
+		rt   http.RoundTripper
+	}{
+		{
+			name: "core v1",
+			rt:   extractTransport(client.Kubernetes.CoreV1()),
+		},
+		{
+			name: "coordination v1",
+			rt:   extractTransport(client.Kubernetes.CoordinationV1()),
+		},
+		{
+			name: "api registration v1",
+			rt:   extractTransport(client.Aggregation.ApiregistrationV1()),
+		},
+		{
+			name: "concierge login",
+			rt:   extractTransport(client.PinnipedConcierge.LoginV1alpha1()),
+		},
+		{
+			name: "concierge config",
+			rt:   extractTransport(client.PinnipedConcierge.ConfigV1alpha1()),
+		},
+		{
+			name: "supervisor idp",
+			rt:   extractTransport(client.PinnipedSupervisor.IDPV1alpha1()),
+		},
+		{
+			name: "supervisor config",
+			rt:   extractTransport(client.PinnipedSupervisor.ConfigV1alpha1()),
+		},
+		{
+			name: "json config",
+			rt:   configToTransport(t, client.JSONConfig),
+		},
+		{
+			name: "proto config",
+			rt:   configToTransport(t, client.ProtoConfig),
+		},
+		{
+			name: "anonymous json config",
+			rt:   configToTransport(t, SecureAnonymousClientConfig(client.JSONConfig)),
+		},
+		{
+			name: "anonymous proto config",
+			rt:   configToTransport(t, SecureAnonymousClientConfig(client.ProtoConfig)),
+		},
+		{
+			name: "json config - no cache",
+			rt:   configToTransport(t, bustTLSCache(client.JSONConfig)),
+		},
+		{
+			name: "proto config - no cache",
+			rt:   configToTransport(t, bustTLSCache(client.ProtoConfig)),
+		},
+		{
+			name: "anonymous json config - no cache, inner bust",
+			rt:   configToTransport(t, SecureAnonymousClientConfig(bustTLSCache(client.JSONConfig))),
+		},
+		{
+			name: "anonymous proto config - no cache, inner bust",
+			rt:   configToTransport(t, SecureAnonymousClientConfig(bustTLSCache(client.ProtoConfig))),
+		},
+		{
+			name: "anonymous json config - no cache, double bust",
+			rt:   configToTransport(t, bustTLSCache(SecureAnonymousClientConfig(bustTLSCache(client.JSONConfig)))),
+		},
+		{
+			name: "anonymous proto config - no cache, double bust",
+			rt:   configToTransport(t, bustTLSCache(SecureAnonymousClientConfig(bustTLSCache(client.ProtoConfig)))),
+		},
+		{
+			name: "anonymous json config - no cache, outer bust",
+			rt:   configToTransport(t, bustTLSCache(SecureAnonymousClientConfig(client.JSONConfig))),
+		},
+		{
+			name: "anonymous proto config - no cache, outer bust",
+			rt:   configToTransport(t, bustTLSCache(SecureAnonymousClientConfig(client.ProtoConfig))),
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel() // make sure to run in parallel to confirm that our client-go TLS cache busting works (i.e. assert no data races)
+
+			tlsConfig, err := netTLSClientConfig(tt.rt)
+			require.NoError(t, err)
+			require.NotNil(t, tlsConfig)
+
+			secureTLSConfig := ptls.Secure(nil)
+
+			require.Equal(t, secureTLSConfig.MinVersion, tlsConfig.MinVersion)
+			require.Equal(t, secureTLSConfig.CipherSuites, tlsConfig.CipherSuites)
+			require.Equal(t, secureTLSConfig.NextProtos, tlsConfig.NextProtos)
+
+			// x509.CertPool has some embedded functions that make it hard to compare so just look at the subjects
+			require.Equal(t, serverSubjects, tlsConfig.RootCAs.Subjects())
+		})
+	}
+}
+
+type restClientGetter interface {
+	RESTClient() rest.Interface
+}
+
+func extractTransport(getter restClientGetter) http.RoundTripper {
+	return getter.RESTClient().(*rest.RESTClient).Client.Transport
+}
+
+func configToTransport(t *testing.T, config *rest.Config) http.RoundTripper {
+	t.Helper()
+
+	rt, err := rest.TransportFor(config)
+	require.NoError(t, err)
+	return rt
+}
+
+func bustTLSCache(config *rest.Config) *rest.Config {
+	c := rest.CopyConfig(config)
+	c.Proxy = func(h *http.Request) (*url.URL, error) {
+		return nil, nil // having a non-nil proxy func makes client-go not cache the TLS config
+	}
+	return c
+}
+
+func makeClient(t *testing.T, restConfig *rest.Config, f func(*rest.Config)) *Client {
+	t.Helper()
+
+	restConfig = rest.CopyConfig(restConfig)
+
+	f(restConfig)
+
+	client, err := New(WithConfig(restConfig))
+	require.NoError(t, err)
+
+	return client
+}

internal/kubeclient/roundtrip.go

@@ -20,6 +20,7 @@ import (
 	restclient "k8s.io/client-go/rest"
 	"k8s.io/client-go/transport"
 
+	"go.pinniped.dev/internal/httputil/roundtripper"
 	"go.pinniped.dev/internal/plog"
 )
 
@@ -78,7 +79,7 @@ func newWrapper(
 	middlewares []Middleware,
 ) transport.WrapperFunc {
 	return func(rt http.RoundTripper) http.RoundTripper {
-		return roundTripperFunc(func(req *http.Request) (bool, *http.Response, error) {
+		return roundtripper.WrapFunc(rt, roundTripperFunc(func(req *http.Request) (bool, *http.Response, error) {
 			reqInfo, err := resolver.NewRequestInfo(reqWithoutPrefix(req, hostURL, apiPathPrefix))
 			if err != nil || !reqInfo.IsResourceRequest {
 				resp, err := rt.RoundTrip(req) // we only handle kube resource requests
@@ -120,7 +121,7 @@ func newWrapper(
 				resp, err := rt.RoundTrip(req) // we only handle certain verbs
 				return false, resp, err
 			}
-		})
+		}).RoundTrip)
 	}
 }
 

internal/localuserauthenticator/localuserauthenticator.go

@@ -36,6 +36,7 @@ import (
 	"go.pinniped.dev/internal/constable"
 	"go.pinniped.dev/internal/controller/apicerts"
 	"go.pinniped.dev/internal/controllerlib"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/dynamiccert"
 	"go.pinniped.dev/internal/kubeclient"
 	"go.pinniped.dev/internal/plog"
@@ -71,16 +72,15 @@ func newWebhook(
 // start runs the webhook in a separate goroutine and returns whether or not the
 // webhook was started successfully.
 func (w *webhook) start(ctx context.Context, l net.Listener) error {
-	server := http.Server{
+	c := ptls.Secure(nil)
-		Handler: w,
+	c.GetCertificate = func(_ *tls.ClientHelloInfo) (*tls.Certificate, error) {
-		TLSConfig: &tls.Config{
-			MinVersion: tls.VersionTLS13,
-			GetCertificate: func(_ *tls.ClientHelloInfo) (*tls.Certificate, error) {
 		certPEM, keyPEM := w.certProvider.CurrentCertKeyContent()
 		cert, err := tls.X509KeyPair(certPEM, keyPEM)
 		return &cert, err
-			},
+	}
-		},
+	server := http.Server{
+		Handler:   w,
+		TLSConfig: c,
 	}
 
 	errCh := make(chan error)

internal/localuserauthenticator/localuserauthenticator_test.go

@@ -6,7 +6,6 @@ package localuserauthenticator
 import (
 	"bytes"
 	"context"
-	"crypto/tls"
 	"crypto/x509"
 	"encoding/json"
 	"fmt"
@@ -25,6 +24,7 @@ import (
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	utilnet "k8s.io/apimachinery/pkg/util/net"
 	kubeinformers "k8s.io/client-go/informers"
 	corev1informers "k8s.io/client-go/informers/core/v1"
 	"k8s.io/client-go/kubernetes"
@@ -32,6 +32,7 @@ import (
 
 	"go.pinniped.dev/internal/certauthority"
 	"go.pinniped.dev/internal/dynamiccert"
+	"go.pinniped.dev/internal/net/phttp"
 )
 
 func TestWebhook(t *testing.T) {
@@ -102,7 +103,7 @@ func TestWebhook(t *testing.T) {
 	defer func() { _ = l.Close() }()
 	require.NoError(t, w.start(ctx, l))
 
-	client := newClient(caBundle, serverName)
+	client := newClient(t, caBundle, serverName)
 
 	goodURL := fmt.Sprintf("https://%s/authenticate", l.Addr().String())
 	goodRequestHeaders := map[string][]string{
@@ -475,18 +476,20 @@ func newCertProvider(t *testing.T) (dynamiccert.Private, []byte, string) {
 
 // newClient creates an http.Client that can be used to make an HTTPS call to a
 // service whose serving certs can be verified by the provided CA bundle.
-func newClient(caBundle []byte, serverName string) *http.Client {
+func newClient(t *testing.T, caBundle []byte, serverName string) *http.Client {
+	t.Helper()
+
 	rootCAs := x509.NewCertPool()
-	rootCAs.AppendCertsFromPEM(caBundle)
+	ok := rootCAs.AppendCertsFromPEM(caBundle)
-	return &http.Client{
+	require.True(t, ok)
-		Transport: &http.Transport{
+
-			TLSClientConfig: &tls.Config{
+	c := phttp.Secure(rootCAs)
-				MinVersion: tls.VersionTLS13,
+
-				RootCAs:    rootCAs,
+	tlsConfig, err := utilnet.TLSClientConfig(c.Transport)
-				ServerName: serverName,
+	require.NoError(t, err)
-			},
+	tlsConfig.ServerName = serverName
-		},
+
-	}
+	return c
 }
 
 // newTokenReviewBody creates an io.ReadCloser that contains a JSON-encodeed

internal/net/phttp/debug.go

@@ -0,0 +1,118 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package phttp
+
+import (
+	"net/http"
+	"net/url"
+
+	"k8s.io/client-go/transport"
+
+	"go.pinniped.dev/internal/httputil/roundtripper"
+)
+
+func safeDebugWrappers(rt http.RoundTripper, f transport.WrapperFunc, shouldLog func() bool) http.RoundTripper {
+	return roundtripper.WrapFunc(rt, func(req *http.Request) (*http.Response, error) {
+		// minor optimization to avoid the cleaning logic when the debug wrappers are unused
+		// note: do not make this entire wrapper conditional on shouldLog() - the output is allowed to change at runtime
+		if !shouldLog() {
+			return rt.RoundTrip(req)
+		}
+
+		var (
+			resp *http.Response
+			err  error
+		)
+		debugRT := f(roundtripper.Func(func(_ *http.Request) (*http.Response, error) {
+			// this call needs to be inside this closure so that the debug wrappers can time it
+			// note also that it takes the original (real) request
+			resp, err = rt.RoundTrip(req)
+
+			cleanedResp := cleanResp(resp) // do not leak the user's password during the password grant
+
+			return cleanedResp, err
+		}))
+
+		// run the debug wrappers for their side effects (i.e. logging)
+		// the output is ignored because the input is not the real request
+		cleanedReq := cleanReq(req) // do not leak the user's password during the password grant
+		_, _ = debugRT.RoundTrip(cleanedReq)
+
+		return resp, err
+	})
+}
+
+func cleanReq(req *http.Request) *http.Request {
+	// only pass back things we know to be safe to log
+	return &http.Request{
+		Method: req.Method,
+		URL:    cleanURL(req.URL),
+		Header: cleanHeader(req.Header),
+	}
+}
+
+func cleanResp(resp *http.Response) *http.Response {
+	if resp == nil {
+		return nil
+	}
+
+	// only pass back things we know to be safe to log
+	return &http.Response{
+		Status: resp.Status,
+		Header: cleanHeader(resp.Header),
+	}
+}
+
+func cleanURL(u *url.URL) *url.URL {
+	var user *url.Userinfo
+	if len(u.User.Username()) > 0 {
+		user = url.User("masked_username")
+	}
+
+	var opaque string
+	if len(u.Opaque) > 0 {
+		opaque = "masked_opaque_data"
+	}
+
+	var fragment string
+	if len(u.Fragment) > 0 || len(u.RawFragment) > 0 {
+		fragment = "masked_fragment"
+	}
+
+	// only pass back things we know to be safe to log
+	return &url.URL{
+		Scheme:     u.Scheme,
+		Opaque:     opaque,
+		User:       user,
+		Host:       u.Host,
+		Path:       u.Path,
+		RawPath:    u.RawPath,
+		ForceQuery: u.ForceQuery,
+		RawQuery:   cleanQuery(u.Query()),
+		Fragment:   fragment,
+	}
+}
+
+func cleanQuery(query url.Values) string {
+	if len(query) == 0 {
+		return ""
+	}
+
+	out := url.Values(cleanHeader(http.Header(query))) // cast so we can re-use logic
+	return out.Encode()
+}
+
+func cleanHeader(header http.Header) http.Header {
+	if len(header) == 0 {
+		return nil
+	}
+
+	mask := []string{"masked_value"}
+	out := make(http.Header, len(header))
+	for key := range header {
+		out[key] = mask // only copy the keys
+	}
+
+	return out
+}

internal/net/phttp/debug_test.go

@@ -0,0 +1,340 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package phttp
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"net/http"
+	"net/url"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"go.pinniped.dev/internal/constable"
+	"go.pinniped.dev/internal/httputil/roundtripper"
+)
+
+func Test_safeDebugWrappers_shouldLog(t *testing.T) {
+	t.Parallel()
+
+	var rtFuncCalled, wrapFuncCalled, innerRTCalled int
+	var shouldLog, skipInnerRT bool
+
+	shouldLogFunc := func() bool { return shouldLog }
+
+	rtFunc := roundtripper.Func(func(_ *http.Request) (*http.Response, error) {
+		rtFuncCalled++
+		return nil, nil
+	})
+
+	wrapFunc := func(rt http.RoundTripper) http.RoundTripper {
+		wrapFuncCalled++
+		return roundtripper.Func(func(r *http.Request) (*http.Response, error) {
+			innerRTCalled++
+			if skipInnerRT {
+				return nil, nil
+			}
+			return rt.RoundTrip(r)
+		})
+	}
+
+	r := testReq(t, nil, nil)
+
+	out := safeDebugWrappers(rtFunc, wrapFunc, shouldLogFunc)
+
+	// assert that shouldLogFunc is dynamically honored
+
+	_, _ = out.RoundTrip(r) //nolint:bodyclose
+
+	require.Equal(t, 1, rtFuncCalled)
+	require.Equal(t, 0, wrapFuncCalled)
+	require.Equal(t, 0, innerRTCalled)
+
+	shouldLog = true
+
+	_, _ = out.RoundTrip(r) //nolint:bodyclose
+
+	require.Equal(t, 2, rtFuncCalled)
+	require.Equal(t, 1, wrapFuncCalled)
+	require.Equal(t, 1, innerRTCalled)
+
+	shouldLog = false
+
+	_, _ = out.RoundTrip(r) //nolint:bodyclose
+
+	require.Equal(t, 3, rtFuncCalled)
+	require.Equal(t, 1, wrapFuncCalled)
+	require.Equal(t, 1, innerRTCalled)
+
+	shouldLog = true
+
+	_, _ = out.RoundTrip(r) //nolint:bodyclose
+
+	require.Equal(t, 4, rtFuncCalled)
+	require.Equal(t, 2, wrapFuncCalled)
+	require.Equal(t, 2, innerRTCalled)
+
+	// assert that wrapFunc controls rtFunc being called
+
+	skipInnerRT = true
+
+	_, _ = out.RoundTrip(r) //nolint:bodyclose
+
+	require.Equal(t, 4, rtFuncCalled)
+	require.Equal(t, 3, wrapFuncCalled)
+	require.Equal(t, 3, innerRTCalled)
+
+	skipInnerRT = false
+
+	_, _ = out.RoundTrip(r) //nolint:bodyclose
+
+	require.Equal(t, 5, rtFuncCalled)
+	require.Equal(t, 4, wrapFuncCalled)
+	require.Equal(t, 4, innerRTCalled)
+}
+
+func Test_safeDebugWrappers_clean(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name             string
+		shouldLog        bool
+		inReq, wantReq   *http.Request
+		inResp, wantResp *http.Response
+		inErr            error
+	}{
+		{
+			name:      "header cleaned",
+			shouldLog: true,
+			inReq:     testReq(t, http.Header{"hello": {"from", "earth"}}, nil),
+			wantReq:   testCleanReq(http.Header{"hello": {"masked_value"}}, nil),
+			inResp:    testResp(t, http.Header{"bye": {"for", "now"}}),     //nolint:bodyclose
+			wantResp:  testCleanResp(http.Header{"bye": {"masked_value"}}), //nolint:bodyclose
+			inErr:     nil,
+		},
+		{
+			name:      "header cleaned error",
+			shouldLog: true,
+			inReq:     testReq(t, http.Header{"see": {"from", "mars"}}, nil),
+			wantReq:   testCleanReq(http.Header{"see": {"masked_value"}}, nil),
+			inResp:    testResp(t, http.Header{"bear": {"is", "a"}}),        //nolint:bodyclose
+			wantResp:  testCleanResp(http.Header{"bear": {"masked_value"}}), //nolint:bodyclose
+			inErr:     constable.Error("some error"),
+		},
+		{
+			name:      "header cleaned error nil resp",
+			shouldLog: true,
+			inReq:     testReq(t, http.Header{"see": {"from", "mars"}}, nil),
+			wantReq:   testCleanReq(http.Header{"see": {"masked_value"}}, nil),
+			inResp:    nil,
+			wantResp:  nil,
+			inErr:     constable.Error("some other error"),
+		},
+		{
+			name:      "header cleaned no log",
+			shouldLog: false,
+			inReq:     testReq(t, http.Header{"sky": {"is", "blue"}}, nil),
+			wantReq:   nil,
+			inResp:    testResp(t, http.Header{"night": {"is", "dark"}}), //nolint:bodyclose
+			wantResp:  nil,
+			inErr:     nil,
+		},
+		{
+			name:      "url cleaned, all fields",
+			shouldLog: true,
+			inReq: testReq(t, nil, &url.URL{
+				Scheme:      "sc",
+				Opaque:      "op",
+				User:        url.UserPassword("us", "pa"),
+				Host:        "ho",
+				Path:        "pa",
+				RawPath:     "rap",
+				ForceQuery:  true,
+				RawQuery:    "key1=val1&key2=val2",
+				Fragment:    "fra",
+				RawFragment: "rawf",
+			}),
+			wantReq: testCleanReq(nil, &url.URL{
+				Scheme:      "sc",
+				Opaque:      "masked_opaque_data",
+				User:        url.User("masked_username"),
+				Host:        "ho",
+				Path:        "pa",
+				RawPath:     "rap",
+				ForceQuery:  true,
+				RawQuery:    "key1=masked_value&key2=masked_value",
+				Fragment:    "masked_fragment",
+				RawFragment: "",
+			}),
+			inResp:   testResp(t, http.Header{"sun": {"yellow"}}),         //nolint:bodyclose
+			wantResp: testCleanResp(http.Header{"sun": {"masked_value"}}), //nolint:bodyclose
+			inErr:    nil,
+		},
+		{
+			name:      "url cleaned, some fields",
+			shouldLog: true,
+			inReq: testReq(t, nil, &url.URL{
+				Scheme:      "sc",
+				Opaque:      "",
+				User:        nil,
+				Host:        "ho",
+				Path:        "pa",
+				RawPath:     "rap",
+				ForceQuery:  false,
+				RawQuery:    "key3=val3&key4=val4",
+				Fragment:    "",
+				RawFragment: "",
+			}),
+			wantReq: testCleanReq(nil, &url.URL{
+				Scheme:      "sc",
+				Opaque:      "",
+				User:        nil,
+				Host:        "ho",
+				Path:        "pa",
+				RawPath:     "rap",
+				ForceQuery:  false,
+				RawQuery:    "key3=masked_value&key4=masked_value",
+				Fragment:    "",
+				RawFragment: "",
+			}),
+			inResp:   testResp(t, http.Header{"sun": {"yellow"}}),         //nolint:bodyclose
+			wantResp: testCleanResp(http.Header{"sun": {"masked_value"}}), //nolint:bodyclose
+			inErr:    nil,
+		},
+		{
+			name:      "header and url cleaned, all fields with error",
+			shouldLog: true,
+			inReq: testReq(t, http.Header{"zone": {"of", "the", "enders"}, "welcome": {"home"}}, &url.URL{
+				Scheme:      "sc2",
+				Opaque:      "op2",
+				User:        url.UserPassword("us2", "pa2"),
+				Host:        "ho2",
+				Path:        "pa2",
+				RawPath:     "rap2",
+				ForceQuery:  true,
+				RawQuery:    "a=b&c=d&e=f&a=1&a=2",
+				Fragment:    "fra2",
+				RawFragment: "rawf2",
+			}),
+			wantReq: testCleanReq(http.Header{"zone": {"masked_value"}, "welcome": {"masked_value"}}, &url.URL{
+				Scheme:      "sc2",
+				Opaque:      "masked_opaque_data",
+				User:        url.User("masked_username"),
+				Host:        "ho2",
+				Path:        "pa2",
+				RawPath:     "rap2",
+				ForceQuery:  true,
+				RawQuery:    "a=masked_value&c=masked_value&e=masked_value",
+				Fragment:    "masked_fragment",
+				RawFragment: "",
+			}),
+			inResp:   testResp(t, http.Header{"moon": {"white"}}),          //nolint:bodyclose
+			wantResp: testCleanResp(http.Header{"moon": {"masked_value"}}), //nolint:bodyclose
+			inErr:    constable.Error("yay pandas"),
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			var rtCalled, wrapCalled, innerCalled bool
+
+			rtFunc := roundtripper.Func(func(r *http.Request) (*http.Response, error) {
+				rtCalled = true
+				require.Equal(t, tt.inReq, r)
+				return tt.inResp, tt.inErr
+			})
+
+			var gotReq *http.Request
+			var gotResp *http.Response
+			var gotErr error
+
+			wrapFunc := func(rt http.RoundTripper) http.RoundTripper {
+				wrapCalled = true
+				return roundtripper.Func(func(r *http.Request) (*http.Response, error) {
+					innerCalled = true
+
+					gotReq = r
+
+					resp, err := rt.RoundTrip(r) //nolint:bodyclose
+
+					gotResp = resp
+					gotErr = err
+
+					return resp, err
+				})
+			}
+
+			out := safeDebugWrappers(rtFunc, wrapFunc, func() bool { return tt.shouldLog })
+
+			resp, err := out.RoundTrip(tt.inReq) //nolint:bodyclose
+
+			require.Equal(t, tt.inResp, resp)
+			require.Equal(t, tt.inErr, err)
+			require.True(t, rtCalled)
+			require.Equal(t, tt.shouldLog, wrapCalled)
+			require.Equal(t, tt.shouldLog, innerCalled)
+
+			require.Equal(t, tt.wantReq, gotReq)
+			require.Equal(t, tt.wantResp, gotResp)
+			require.Equal(t, tt.inErr, gotErr)
+		})
+	}
+}
+
+func testReq(t *testing.T, header http.Header, u *url.URL) *http.Request {
+	t.Helper()
+
+	r, err := http.NewRequestWithContext(context.Background(), http.MethodGet, "https://overwritten.com", nil)
+	require.NoError(t, err)
+
+	if u == nil {
+		u = &url.URL{}
+	}
+
+	r.URL = u
+	r.Header = header
+
+	// something non-nil for testing
+	r.Body = io.NopCloser(&bytes.Buffer{})
+	r.Form = url.Values{"a": {"b"}}
+	r.PostForm = url.Values{"c": {"d"}}
+
+	return r
+}
+
+func testResp(t *testing.T, header http.Header) *http.Response {
+	t.Helper()
+
+	return &http.Response{
+		Status: "pandas are the best",
+		Header: header,
+
+		// something non-nil for testing
+		Body:    io.NopCloser(&bytes.Buffer{}),
+		Request: testReq(t, header, nil),
+	}
+}
+
+func testCleanReq(header http.Header, u *url.URL) *http.Request {
+	if u == nil {
+		u = &url.URL{}
+	}
+
+	return &http.Request{
+		Method: http.MethodGet,
+		URL:    u,
+		Header: header,
+	}
+}
+
+func testCleanResp(header http.Header) *http.Response {
+	return &http.Response{
+		Status: "pandas are the best",
+		Header: header,
+	}
+}

internal/net/phttp/phttp.go

@@ -0,0 +1,48 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package phttp
+
+import (
+	"crypto/x509"
+	"net/http"
+	"time"
+
+	"k8s.io/apimachinery/pkg/util/net"
+	"k8s.io/client-go/rest"
+	"k8s.io/client-go/transport"
+
+	"go.pinniped.dev/internal/crypto/ptls"
+	"go.pinniped.dev/internal/plog"
+)
+
+func Default(rootCAs *x509.CertPool) *http.Client {
+	return buildClient(ptls.Default, rootCAs)
+}
+
+func Secure(rootCAs *x509.CertPool) *http.Client {
+	return buildClient(ptls.Secure, rootCAs)
+}
+
+func buildClient(tlsConfigFunc ptls.ConfigFunc, rootCAs *x509.CertPool) *http.Client {
+	baseRT := defaultTransport()
+	baseRT.TLSClientConfig = tlsConfigFunc(rootCAs)
+
+	return &http.Client{
+		Transport: defaultWrap(baseRT),
+		Timeout:   3 * time.Hour, // make it impossible for requests to hang indefinitely
+	}
+}
+
+func defaultTransport() *http.Transport {
+	baseRT := http.DefaultTransport.(*http.Transport).Clone()
+	net.SetTransportDefaults(baseRT)
+	baseRT.MaxIdleConnsPerHost = 25 // copied from client-go
+	return baseRT
+}
+
+func defaultWrap(rt http.RoundTripper) http.RoundTripper {
+	rt = safeDebugWrappers(rt, transport.DebugWrappers, func() bool { return plog.Enabled(plog.LevelTrace) })
+	rt = transport.NewUserAgentRoundTripper(rest.DefaultKubernetesUserAgent(), rt)
+	return rt
+}

internal/net/phttp/phttp_test.go

@@ -0,0 +1,116 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package phttp
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"k8s.io/apimachinery/pkg/util/net"
+	"k8s.io/client-go/util/cert"
+
+	"go.pinniped.dev/internal/crypto/ptls"
+	"go.pinniped.dev/internal/testutil/tlsserver"
+)
+
+// TestUnwrap ensures that the http.Client structs returned by this package contain
+// a transport that can be fully unwrapped to get access to the underlying TLS config.
+func TestUnwrap(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name string
+		f    func(*x509.CertPool) *http.Client
+	}{
+		{
+			name: "default",
+			f:    Default,
+		},
+		{
+			name: "secure",
+			f:    Secure,
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			p, err := x509.SystemCertPool()
+			require.NoError(t, err)
+
+			c := tt.f(p)
+
+			tlsConfig, err := net.TLSClientConfig(c.Transport)
+			require.NoError(t, err)
+			require.NotNil(t, tlsConfig)
+
+			require.NotEmpty(t, tlsConfig.NextProtos)
+			require.GreaterOrEqual(t, tlsConfig.MinVersion, uint16(tls.VersionTLS12))
+			require.Equal(t, p, tlsConfig.RootCAs)
+		})
+	}
+}
+
+func TestClient(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		clientFunc func(*x509.CertPool) *http.Client
+		configFunc ptls.ConfigFunc
+	}{
+		{
+			name:       "default",
+			clientFunc: Default,
+			configFunc: ptls.Default,
+		},
+		{
+			name:       "secure",
+			clientFunc: Secure,
+			configFunc: ptls.Secure,
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			var sawRequest bool
+			server := tlsserver.TLSTestServer(t, http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
+				tlsserver.AssertTLS(t, r, tt.configFunc)
+				assertUserAgent(t, r)
+				sawRequest = true
+			}), tlsserver.RecordTLSHello)
+
+			rootCAs, err := cert.NewPoolFromBytes(tlsserver.TLSTestServerCA(server))
+			require.NoError(t, err)
+
+			c := tt.clientFunc(rootCAs)
+
+			req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, server.URL, nil)
+			require.NoError(t, err)
+
+			resp, err := c.Do(req)
+			require.NoError(t, err)
+			require.NoError(t, resp.Body.Close())
+
+			require.True(t, sawRequest)
+		})
+	}
+}
+
+func assertUserAgent(t *testing.T, r *http.Request) {
+	t.Helper()
+
+	ua := r.Header.Get("user-agent")
+
+	// use assert instead of require to not break the http.Handler with a panic
+	assert.Contains(t, ua, ") kubernetes/")
+}

internal/oidc/downstreamsession/downstream_session.go

@@ -9,7 +9,7 @@ import (
 	"net/url"
 	"time"
 
-	oidc2 "github.com/coreos/go-oidc/v3/oidc"
+	coreosoidc "github.com/coreos/go-oidc/v3/oidc"
 	"github.com/ory/fosite"
 	"github.com/ory/fosite/handler/openid"
 	"github.com/ory/fosite/token/jwt"
@@ -60,8 +60,8 @@ func MakeDownstreamSession(subject string, username string, groups []string, cus
 
 // GrantScopesIfRequested auto-grants the scopes for which we do not require end-user approval, if they were requested.
 func GrantScopesIfRequested(authorizeRequester fosite.AuthorizeRequester) {
-	oidc.GrantScopeIfRequested(authorizeRequester, oidc2.ScopeOpenID)
+	oidc.GrantScopeIfRequested(authorizeRequester, coreosoidc.ScopeOpenID)
-	oidc.GrantScopeIfRequested(authorizeRequester, oidc2.ScopeOfflineAccess)
+	oidc.GrantScopeIfRequested(authorizeRequester, coreosoidc.ScopeOfflineAccess)
 	oidc.GrantScopeIfRequested(authorizeRequester, "pinniped:request-audience")
 }
 

internal/plog/klog.go

@@ -33,7 +33,7 @@ func RemoveKlogGlobalFlags() {
 	}
 }
 
-// KRef is (mostly) copied from klog - it is a standard way to represent a a metav1.Object in logs
+// KRef is (mostly) copied from klog - it is a standard way to represent a metav1.Object in logs
 // when you only have access to the namespace and name of the object.
 func KRef(namespace, name string) string {
 	return fmt.Sprintf("%s/%s", namespace, name)
@@ -44,33 +44,19 @@ func KObj(obj klog.KMetadata) string {
 	return fmt.Sprintf("%s/%s", obj.GetNamespace(), obj.GetName())
 }
 
-func klogLevelForPlogLevel(plogLevel LogLevel) (klogLevel klog.Level) {
+func klogLevelForPlogLevel(plogLevel LogLevel) klog.Level {
 	switch plogLevel {
 	case LevelWarning:
-		klogLevel = klogLevelWarning // unset means minimal logs (Error and Warning)
+		return klogLevelWarning // unset means minimal logs (Error and Warning)
 	case LevelInfo:
-		klogLevel = klogLevelInfo
+		return klogLevelInfo
 	case LevelDebug:
-		klogLevel = klogLevelDebug
+		return klogLevelDebug
 	case LevelTrace:
-		klogLevel = klogLevelTrace
+		return klogLevelTrace
 	case LevelAll:
-		klogLevel = klogLevelAll + 100 // make all really mean all
+		return klogLevelAll + 100 // make all really mean all
 	default:
-		klogLevel = -1
-	}
-
-	return
-}
-
-func getKlogLevel() klog.Level {
-	// hack around klog not exposing a Get method
-	for i := klog.Level(0); i < 256; i++ {
-		if klog.V(i).Enabled() {
-			continue
-		}
-		return i - 1
-	}
-
 		return -1
 	}
+}

internal/plog/level.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 
 	"k8s.io/component-base/logs"
+	"k8s.io/klog/v2"
 
 	"go.pinniped.dev/internal/constable"
 )
@@ -54,5 +55,5 @@ func ValidateAndSetLogLevelGlobally(level LogLevel) error {
 // Enabled returns whether the provided plog level is enabled, i.e., whether print statements at the
 // provided level will show up.
 func Enabled(level LogLevel) bool {
-	return getKlogLevel() >= klogLevelForPlogLevel(level)
+	return klog.V(klogLevelForPlogLevel(level)).Enabled()
 }

internal/plog/level_test.go

@@ -114,3 +114,15 @@ func undoGlobalLogLevelChanges(t *testing.T, originalLogLevel klog.Level) {
 	_, err := logs.GlogSetter(strconv.Itoa(int(originalLogLevel)))
 	require.NoError(t, err)
 }
+
+func getKlogLevel() klog.Level {
+	// hack around klog not exposing a Get method
+	for i := klog.Level(0); i < 256; i++ {
+		if klog.V(i).Enabled() {
+			continue
+		}
+		return i - 1
+	}
+
+	return -1
+}

internal/plog/plog.go

@@ -26,13 +26,11 @@
 // act of desperation to determine why the system is broken.
 package plog
 
-import (
+import "k8s.io/klog/v2"
-	"k8s.io/klog/v2"
-)
 
 const errorKey = "error"
 
-type _ interface {
+type Logger interface {
 	Error(msg string, err error, keysAndValues ...interface{})
 	Warning(msg string, keysAndValues ...interface{})
 	WarningErr(msg string, err error, keysAndValues ...interface{})
@@ -45,23 +43,23 @@ type _ interface {
 	All(msg string, keysAndValues ...interface{})
 }
 
-type PLogger struct {
+type pLogger struct {
 	prefix string
 	depth  int
 }
 
-func New(prefix string) PLogger {
+func New(prefix string) Logger {
-	return PLogger{
+	return &pLogger{
 		depth:  0,
 		prefix: prefix,
 	}
 }
 
-func (p *PLogger) Error(msg string, err error, keysAndValues ...interface{}) {
+func (p *pLogger) Error(msg string, err error, keysAndValues ...interface{}) {
 	klog.ErrorSDepth(p.depth+1, err, p.prefix+msg, keysAndValues...)
 }
 
-func (p *PLogger) warningDepth(msg string, depth int, keysAndValues ...interface{}) {
+func (p *pLogger) warningDepth(msg string, depth int, keysAndValues ...interface{}) {
 	// klog's structured logging has no concept of a warning (i.e. no WarningS function)
 	// Thus we use info at log level zero as a proxy
 	// klog's info logs have an I prefix and its warning logs have a W prefix
@@ -72,111 +70,111 @@ func (p *PLogger) warningDepth(msg string, depth int, keysAndValues ...interface
 	}
 }
 
-func (p *PLogger) Warning(msg string, keysAndValues ...interface{}) {
+func (p *pLogger) Warning(msg string, keysAndValues ...interface{}) {
 	p.warningDepth(msg, p.depth+1, keysAndValues...)
 }
 
 // Use WarningErr to issue a Warning message with an error object as part of the message.
-func (p *PLogger) WarningErr(msg string, err error, keysAndValues ...interface{}) {
+func (p *pLogger) WarningErr(msg string, err error, keysAndValues ...interface{}) {
 	p.warningDepth(msg, p.depth+1, append([]interface{}{errorKey, err}, keysAndValues...)...)
 }
 
-func (p *PLogger) infoDepth(msg string, depth int, keysAndValues ...interface{}) {
+func (p *pLogger) infoDepth(msg string, depth int, keysAndValues ...interface{}) {
 	if klog.V(klogLevelInfo).Enabled() {
 		klog.InfoSDepth(depth+1, p.prefix+msg, keysAndValues...)
 	}
 }
 
-func (p *PLogger) Info(msg string, keysAndValues ...interface{}) {
+func (p *pLogger) Info(msg string, keysAndValues ...interface{}) {
 	p.infoDepth(msg, p.depth+1, keysAndValues...)
 }
 
 // Use InfoErr to log an expected error, e.g. validation failure of an http parameter.
-func (p *PLogger) InfoErr(msg string, err error, keysAndValues ...interface{}) {
+func (p *pLogger) InfoErr(msg string, err error, keysAndValues ...interface{}) {
 	p.infoDepth(msg, p.depth+1, append([]interface{}{errorKey, err}, keysAndValues...)...)
 }
 
-func (p *PLogger) debugDepth(msg string, depth int, keysAndValues ...interface{}) {
+func (p *pLogger) debugDepth(msg string, depth int, keysAndValues ...interface{}) {
 	if klog.V(klogLevelDebug).Enabled() {
 		klog.InfoSDepth(depth+1, p.prefix+msg, keysAndValues...)
 	}
 }
 
-func (p *PLogger) Debug(msg string, keysAndValues ...interface{}) {
+func (p *pLogger) Debug(msg string, keysAndValues ...interface{}) {
 	p.debugDepth(msg, p.depth+1, keysAndValues...)
 }
 
 // Use DebugErr to issue a Debug message with an error object as part of the message.
-func (p *PLogger) DebugErr(msg string, err error, keysAndValues ...interface{}) {
+func (p *pLogger) DebugErr(msg string, err error, keysAndValues ...interface{}) {
 	p.debugDepth(msg, p.depth+1, append([]interface{}{errorKey, err}, keysAndValues...)...)
 }
 
-func (p *PLogger) traceDepth(msg string, depth int, keysAndValues ...interface{}) {
+func (p *pLogger) traceDepth(msg string, depth int, keysAndValues ...interface{}) {
 	if klog.V(klogLevelTrace).Enabled() {
 		klog.InfoSDepth(depth+1, p.prefix+msg, keysAndValues...)
 	}
 }
 
-func (p *PLogger) Trace(msg string, keysAndValues ...interface{}) {
+func (p *pLogger) Trace(msg string, keysAndValues ...interface{}) {
 	p.traceDepth(msg, p.depth+1, keysAndValues...)
 }
 
 // Use TraceErr to issue a Trace message with an error object as part of the message.
-func (p *PLogger) TraceErr(msg string, err error, keysAndValues ...interface{}) {
+func (p *pLogger) TraceErr(msg string, err error, keysAndValues ...interface{}) {
 	p.traceDepth(msg, p.depth+1, append([]interface{}{errorKey, err}, keysAndValues...)...)
 }
 
-func (p *PLogger) All(msg string, keysAndValues ...interface{}) {
+func (p *pLogger) All(msg string, keysAndValues ...interface{}) {
 	if klog.V(klogLevelAll).Enabled() {
 		klog.InfoSDepth(p.depth+1, p.prefix+msg, keysAndValues...)
 	}
 }
 
-var pLogger = PLogger{ //nolint:gochecknoglobals
+var logger Logger = &pLogger{ //nolint:gochecknoglobals
 	depth: 1,
 }
 
 // Use Error to log an unexpected system error.
 func Error(msg string, err error, keysAndValues ...interface{}) {
-	pLogger.Error(msg, err, keysAndValues...)
+	logger.Error(msg, err, keysAndValues...)
 }
 
 func Warning(msg string, keysAndValues ...interface{}) {
-	pLogger.Warning(msg, keysAndValues...)
+	logger.Warning(msg, keysAndValues...)
 }
 
 // Use WarningErr to issue a Warning message with an error object as part of the message.
 func WarningErr(msg string, err error, keysAndValues ...interface{}) {
-	pLogger.WarningErr(msg, err, keysAndValues...)
+	logger.WarningErr(msg, err, keysAndValues...)
 }
 
 func Info(msg string, keysAndValues ...interface{}) {
-	pLogger.Info(msg, keysAndValues...)
+	logger.Info(msg, keysAndValues...)
 }
 
 // Use InfoErr to log an expected error, e.g. validation failure of an http parameter.
 func InfoErr(msg string, err error, keysAndValues ...interface{}) {
-	pLogger.InfoErr(msg, err, keysAndValues...)
+	logger.InfoErr(msg, err, keysAndValues...)
 }
 
 func Debug(msg string, keysAndValues ...interface{}) {
-	pLogger.Debug(msg, keysAndValues...)
+	logger.Debug(msg, keysAndValues...)
 }
 
 // Use DebugErr to issue a Debug message with an error object as part of the message.
 func DebugErr(msg string, err error, keysAndValues ...interface{}) {
-	pLogger.DebugErr(msg, err, keysAndValues...)
+	logger.DebugErr(msg, err, keysAndValues...)
 }
 
 func Trace(msg string, keysAndValues ...interface{}) {
-	pLogger.Trace(msg, keysAndValues...)
+	logger.Trace(msg, keysAndValues...)
 }
 
 // Use TraceErr to issue a Trace message with an error object as part of the message.
 func TraceErr(msg string, err error, keysAndValues ...interface{}) {
-	pLogger.TraceErr(msg, err, keysAndValues...)
+	logger.TraceErr(msg, err, keysAndValues...)
 }
 
 func All(msg string, keysAndValues ...interface{}) {
-	pLogger.All(msg, keysAndValues...)
+	logger.All(msg, keysAndValues...)
 }

internal/supervisor/server/server.go

@@ -41,6 +41,7 @@ import (
 	"go.pinniped.dev/internal/controller/supervisorstorage"
 	"go.pinniped.dev/internal/controllerinit"
 	"go.pinniped.dev/internal/controllerlib"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/deploymentref"
 	"go.pinniped.dev/internal/downward"
 	"go.pinniped.dev/internal/groupsuffix"
@@ -393,10 +394,8 @@ func runSupervisor(podInfo *downward.PodInfo, cfg *supervisor.Config) error {
 	defer func() { _ = httpListener.Close() }()
 	startServer(ctx, shutdown, httpListener, oidProvidersManager)
 
-	//nolint: gosec // Intentionally binding to all network interfaces.
+	c := ptls.Default(nil)
-	httpsListener, err := tls.Listen("tcp", ":8443", &tls.Config{
+	c.GetCertificate = func(info *tls.ClientHelloInfo) (*tls.Certificate, error) {
-		MinVersion: tls.VersionTLS12, // Allow v1.2 because clients like the default `curl` on MacOS don't support 1.3 yet.
-		GetCertificate: func(info *tls.ClientHelloInfo) (*tls.Certificate, error) {
 		cert := dynamicTLSCertProvider.GetTLSCert(strings.ToLower(info.ServerName))
 		defaultCert := dynamicTLSCertProvider.GetDefaultTLSCert()
 		plog.Debug("GetCertificate called for port 8443",
@@ -408,8 +407,9 @@ func runSupervisor(podInfo *downward.PodInfo, cfg *supervisor.Config) error {
 			cert = defaultCert
 		}
 		return cert, nil
-		},
+	}
-	})
+	//nolint: gosec // Intentionally binding to all network interfaces.
+	httpsListener, err := tls.Listen("tcp", ":8443", c)
 	if err != nil {
 		return fmt.Errorf("cannot create listener: %w", err)
 	}

internal/testutil/fakekubeapi/fakekubeapi.go

@@ -18,7 +18,6 @@
 package fakekubeapi
 
 import (
-	"encoding/pem"
 	"fmt"
 	"io/ioutil"
 	"mime"
@@ -37,7 +36,9 @@ import (
 
 	pinnipedconciergeclientsetscheme "go.pinniped.dev/generated/latest/client/concierge/clientset/versioned/scheme"
 	pinnipedsupervisorclientsetscheme "go.pinniped.dev/generated/latest/client/supervisor/clientset/versioned/scheme"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/httputil/httperr"
+	"go.pinniped.dev/internal/testutil/tlsserver"
 )
 
 // Start starts an httptest.Server (with TLS) that pretends to be a Kube API server.
@@ -54,7 +55,9 @@ func Start(t *testing.T, resources map[string]runtime.Object) (*httptest.Server,
 		resources = make(map[string]runtime.Object)
 	}
 
-	server := httptest.NewTLSServer(httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) (err error) {
+	server := tlsserver.TLSTestServer(t, httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
+		tlsserver.AssertTLS(t, r, ptls.Secure)
+
 		obj, err := decodeObj(r)
 		if err != nil {
 			return err
@@ -74,11 +77,11 @@ func Start(t *testing.T, resources map[string]runtime.Object) (*httptest.Server,
 		}
 
 		return nil
-	}))
+	}), tlsserver.RecordTLSHello)
 	restConfig := &restclient.Config{
 		Host: server.URL,
 		TLSClientConfig: restclient.TLSClientConfig{
-			CAData: pem.EncodeToMemory(&pem.Block{Bytes: server.Certificate().Raw, Type: "CERTIFICATE"}),
+			CAData: tlsserver.TLSTestServerCA(server),
 		},
 	}
 	return server, restConfig

internal/testutil/tlsserver.go

@@ -5,38 +5,35 @@ package testutil
 
 import (
 	"crypto/tls"
-	"encoding/pem"
 	"errors"
 	"net"
 	"net/http"
-	"net/http/httptest"
 	"testing"
 
 	"github.com/stretchr/testify/require"
+
+	"go.pinniped.dev/internal/crypto/ptls"
+	"go.pinniped.dev/internal/testutil/tlsserver"
 )
 
 // TLSTestServer starts a test server listening on a local port using a test CA. It returns the PEM CA bundle and the
 // URL of the listening server. The lifetime of the server is bound to the provided *testing.T.
-func TLSTestServer(t *testing.T, handler http.HandlerFunc) (caBundlePEM string, url string) {
+func TLSTestServer(t *testing.T, handler http.HandlerFunc) (caBundlePEM, url string) {
 	t.Helper()
-	server := httptest.NewTLSServer(handler)
-	t.Cleanup(server.Close)
 
-	caBundle := string(pem.EncodeToMemory(&pem.Block{
+	server := tlsserver.TLSTestServer(t, handler, nil)
-		Type:  "CERTIFICATE",
+
-		Bytes: server.TLS.Certificates[0].Certificate[0],
+	return string(tlsserver.TLSTestServerCA(server)), server.URL
-	}))
-	return caBundle, server.URL
 }
 
 func TLSTestServerWithCert(t *testing.T, handler http.HandlerFunc, certificate *tls.Certificate) (url string) {
 	t.Helper()
 
+	c := ptls.Default(nil) // mimic API server config
+	c.Certificates = []tls.Certificate{*certificate}
+
 	server := http.Server{
-		TLSConfig: &tls.Config{
+		TLSConfig: c,
-			Certificates: []tls.Certificate{*certificate},
-			MinVersion:   tls.VersionTLS12,
-		},
 		Handler:   handler,
 	}
 

internal/testutil/tlsserver/tlsserver.go

@@ -0,0 +1,110 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package tlsserver
+
+import (
+	"context"
+	"crypto/tls"
+	"encoding/pem"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"reflect"
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"k8s.io/apimachinery/pkg/util/httpstream"
+
+	"go.pinniped.dev/internal/crypto/ptls"
+)
+
+type ctxKey int
+
+const (
+	mapKey ctxKey = iota + 1
+	helloKey
+)
+
+func TLSTestServer(t *testing.T, handler http.Handler, f func(*httptest.Server)) *httptest.Server {
+	t.Helper()
+
+	server := httptest.NewUnstartedServer(handler)
+	server.TLS = ptls.Default(nil) // mimic API server config
+	if f != nil {
+		f(server)
+	}
+	server.StartTLS()
+	t.Cleanup(server.Close)
+	return server
+}
+
+func TLSTestServerCA(server *httptest.Server) []byte {
+	return pem.EncodeToMemory(&pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: server.Certificate().Raw,
+	})
+}
+
+func RecordTLSHello(server *httptest.Server) {
+	server.Config.ConnContext = func(ctx context.Context, _ net.Conn) context.Context {
+		return context.WithValue(ctx, mapKey, &sync.Map{})
+	}
+
+	server.TLS.GetConfigForClient = func(info *tls.ClientHelloInfo) (*tls.Config, error) {
+		m, ok := getCtxMap(info.Context())
+		if !ok {
+			return nil, fmt.Errorf("could not find ctx map")
+		}
+		if actual, loaded := m.LoadOrStore(helloKey, info); loaded && !reflect.DeepEqual(info, actual) {
+			return nil, fmt.Errorf("different client hello seen")
+		}
+		return nil, nil
+	}
+}
+
+func AssertTLS(t *testing.T, r *http.Request, tlsConfigFunc ptls.ConfigFunc) {
+	t.Helper()
+
+	m, ok := getCtxMap(r.Context())
+	require.True(t, ok)
+
+	h, ok := m.Load(helloKey)
+	require.True(t, ok)
+
+	info, ok := h.(*tls.ClientHelloInfo)
+	require.True(t, ok)
+
+	tlsConfig := tlsConfigFunc(nil)
+
+	supportedVersions := []uint16{tlsConfig.MinVersion}
+	ciphers := tlsConfig.CipherSuites
+
+	if secureTLSConfig := ptls.Secure(nil); tlsConfig.MinVersion != secureTLSConfig.MinVersion {
+		supportedVersions = append([]uint16{secureTLSConfig.MinVersion}, supportedVersions...)
+		ciphers = append(ciphers, secureTLSConfig.CipherSuites...)
+	}
+
+	protos := tlsConfig.NextProtos
+	if httpstream.IsUpgradeRequest(r) {
+		protos = tlsConfig.NextProtos[1:]
+	}
+
+	// use assert instead of require to not break the http.Handler with a panic
+	ok1 := assert.Equal(t, supportedVersions, info.SupportedVersions)
+	ok2 := assert.Equal(t, ciphers, info.CipherSuites)
+	ok3 := assert.Equal(t, protos, info.SupportedProtos)
+
+	if all := ok1 && ok2 && ok3; !all {
+		t.Errorf("insecure TLS detected for %q %q %q upgrade=%v supportedVersions=%v ciphers=%v protos=%v",
+			r.Proto, r.Method, r.URL.String(), httpstream.IsUpgradeRequest(r), ok1, ok2, ok3)
+	}
+}
+
+func getCtxMap(ctx context.Context) (*sync.Map, bool) {
+	m, ok := ctx.Value(mapKey).(*sync.Map)
+	return m, ok
+}

internal/upstreamldap/upstreamldap.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/utils/trace"
 
 	"go.pinniped.dev/internal/authenticators"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/endpointaddr"
 	"go.pinniped.dev/internal/oidc/downstreamsession"
 	"go.pinniped.dev/internal/oidc/provider"
@@ -328,7 +329,7 @@ func (p *Provider) tlsConfig() (*tls.Config, error) {
 			return nil, fmt.Errorf("could not parse CA bundle")
 		}
 	}
-	return &tls.Config{MinVersion: tls.VersionTLS12, RootCAs: rootCAs}, nil
+	return ptls.DefaultLDAP(rootCAs), nil
 }
 
 // A name for this upstream provider.

internal/upstreamldap/upstreamldap_test.go

@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
+	"net/http/httptest"
 	"net/url"
 	"testing"
 	"time"
@@ -22,9 +23,11 @@ import (
 
 	"go.pinniped.dev/internal/authenticators"
 	"go.pinniped.dev/internal/certauthority"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/endpointaddr"
 	"go.pinniped.dev/internal/mocks/mockldapconn"
 	"go.pinniped.dev/internal/testutil"
+	"go.pinniped.dev/internal/testutil/tlsserver"
 )
 
 const (
@@ -1689,10 +1692,22 @@ func TestGetURL(t *testing.T) {
 
 // Testing of host parsing, TLS negotiation, and CA bundle, etc. for the production code's dialer.
 func TestRealTLSDialing(t *testing.T) {
-	testServerCABundle, testServerURL := testutil.TLSTestServer(t, func(w http.ResponseWriter, r *http.Request) {})
+	testServer := tlsserver.TLSTestServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}),
-	parsedURL, err := url.Parse(testServerURL)
+		func(server *httptest.Server) {
+			tlsserver.RecordTLSHello(server)
+			recordFunc := server.TLS.GetConfigForClient
+			server.TLS.GetConfigForClient = func(info *tls.ClientHelloInfo) (*tls.Config, error) {
+				_, _ = recordFunc(info)
+				r, err := http.NewRequestWithContext(info.Context(), http.MethodGet, "/this-is-ldap", nil)
+				require.NoError(t, err)
+				tlsserver.AssertTLS(t, r, ptls.DefaultLDAP)
+				return nil, nil
+			}
+		})
+	parsedURL, err := url.Parse(testServer.URL)
 	require.NoError(t, err)
 	testServerHostAndPort := parsedURL.Host
+	testServerCABundle := tlsserver.TLSTestServerCA(testServer)
 
 	caForTestServerWithBadCertName, err := certauthority.New("Test CA", time.Hour)
 	require.NoError(t, err)
@@ -1720,7 +1735,7 @@ func TestRealTLSDialing(t *testing.T) {
 		{
 			name:      "happy path",
 			host:      testServerHostAndPort,
-			caBundle:  []byte(testServerCABundle),
+			caBundle:  testServerCABundle,
 			connProto: TLS,
 			context:   context.Background(),
 		},
@@ -1751,7 +1766,7 @@ func TestRealTLSDialing(t *testing.T) {
 		{
 			name:      "invalid host with TLS",
 			host:      "this:is:not:a:valid:hostname",
-			caBundle:  []byte(testServerCABundle),
+			caBundle:  testServerCABundle,
 			connProto: TLS,
 			context:   context.Background(),
 			wantError: `LDAP Result Code 200 "Network Error": host "this:is:not:a:valid:hostname" is not a valid hostname or IP address`,
@@ -1759,7 +1774,7 @@ func TestRealTLSDialing(t *testing.T) {
 		{
 			name:      "invalid host with StartTLS",
 			host:      "this:is:not:a:valid:hostname",
-			caBundle:  []byte(testServerCABundle),
+			caBundle:  testServerCABundle,
 			connProto: StartTLS,
 			context:   context.Background(),
 			wantError: `LDAP Result Code 200 "Network Error": host "this:is:not:a:valid:hostname" is not a valid hostname or IP address`,
@@ -1776,7 +1791,7 @@ func TestRealTLSDialing(t *testing.T) {
 			name: "cannot connect to host",
 			// This is assuming that this port was not reclaimed by another app since the test setup ran. Seems safe enough.
 			host:      recentlyClaimedHostAndPort,
-			caBundle:  []byte(testServerCABundle),
+			caBundle:  testServerCABundle,
 			connProto: TLS,
 			context:   context.Background(),
 			wantError: fmt.Sprintf(`LDAP Result Code 200 "Network Error": dial tcp %s: connect: connection refused`, recentlyClaimedHostAndPort),
@@ -1784,7 +1799,7 @@ func TestRealTLSDialing(t *testing.T) {
 		{
 			name:      "pays attention to the passed context",
 			host:      testServerHostAndPort,
-			caBundle:  []byte(testServerCABundle),
+			caBundle:  testServerCABundle,
 			connProto: TLS,
 			context:   alreadyCancelledContext,
 			wantError: fmt.Sprintf(`LDAP Result Code 200 "Network Error": dial tcp %s: operation was canceled`, testServerHostAndPort),
@@ -1792,7 +1807,7 @@ func TestRealTLSDialing(t *testing.T) {
 		{
 			name:      "unsupported connection protocol",
 			host:      testServerHostAndPort,
-			caBundle:  []byte(testServerCABundle),
+			caBundle:  testServerCABundle,
 			connProto: "bad usage of this type",
 			context:   alreadyCancelledContext,
 			wantError: `LDAP Result Code 200 "Network Error": did not specify valid ConnectionProtocol`,
@@ -1824,7 +1839,7 @@ func TestRealTLSDialing(t *testing.T) {
 
 				// Indirectly checking that the Dialer method constructed the ldap.Conn with isTLS set to true,
 				// since this is always the correct behavior unless/until we want to support StartTLS.
-				err := conn.(*ldap.Conn).StartTLS(&tls.Config{})
+				err := conn.(*ldap.Conn).StartTLS(ptls.DefaultLDAP(nil))
 				require.EqualError(t, err, `LDAP Result Code 200 "Network Error": ldap: already encrypted`)
 			}
 		})

pkg/oidcclient/login.go

@@ -31,6 +31,7 @@ import (
 	supervisoroidc "go.pinniped.dev/generated/latest/apis/supervisor/oidc"
 	"go.pinniped.dev/internal/httputil/httperr"
 	"go.pinniped.dev/internal/httputil/securityheader"
+	"go.pinniped.dev/internal/net/phttp"
 	"go.pinniped.dev/internal/oidc/provider"
 	"go.pinniped.dev/internal/upstreamoidc"
 	"go.pinniped.dev/pkg/oidcclient/nonce"
@@ -274,7 +275,7 @@ func Login(issuer string, clientID string, opts ...Option) (*oidctypes.Token, er
 		ctx:          context.Background(),
 		logger:       logr.Discard(), // discard logs unless a logger is specified
 		callbacks:    make(chan callbackResult, 2),
-		httpClient:   http.DefaultClient,
+		httpClient:   phttp.Default(nil),
 
 		// Default implementations of external dependencies (to be mocked in tests).
 		generateState: state.Generate,

test/integration/cli_test.go

@@ -108,7 +108,14 @@ func TestCLIGetKubeconfigStaticToken_Parallel(t *testing.T) {
 	})
 }
 
-func runPinnipedCLI(t *testing.T, envVars []string, pinnipedExe string, args ...string) (string, string) {
+type testingT interface {
+	Helper()
+	Errorf(format string, args ...interface{})
+	FailNow()
+	Logf(format string, args ...interface{})
+}
+
+func runPinnipedCLI(t testingT, envVars []string, pinnipedExe string, args ...string) (string, string) {
 	t.Helper()
 	start := time.Now()
 	var stdout, stderr bytes.Buffer

test/integration/concierge_credentialrequest_test.go

@@ -45,8 +45,10 @@ func TestUnsuccessfulCredentialRequest_Parallel(t *testing.T) {
 	require.Equal(t, "authentication failed", *response.Status.Message)
 }
 
-// TCRs are non-mutating and safe to run in parallel with serial tests, see main_test.go.
+// TestSuccessfulCredentialRequest cannot run in parallel because runPinnipedLoginOIDC uses a fixed port
-func TestSuccessfulCredentialRequest_Parallel(t *testing.T) {
+// for its localhost listener via --listen-port=env.CLIUpstreamOIDC.CallbackURL.Port() per oidcLoginCommand.
+// Since ports are global to the process, tests using oidcLoginCommand must be run serially.
+func TestSuccessfulCredentialRequest(t *testing.T) {
 	env := testlib.IntegrationEnv(t).WithCapability(testlib.ClusterSigningKeyIsAvailable)
 
 	ctx, cancel := context.WithTimeout(context.Background(), 6*time.Minute)

test/integration/concierge_impersonation_proxy_test.go

@@ -65,6 +65,7 @@ import (
 	identityv1alpha1 "go.pinniped.dev/generated/latest/apis/concierge/identity/v1alpha1"
 	loginv1alpha1 "go.pinniped.dev/generated/latest/apis/concierge/login/v1alpha1"
 	pinnipedconciergeclientset "go.pinniped.dev/generated/latest/client/concierge/clientset/versioned"
+	"go.pinniped.dev/internal/crypto/ptls"
 	"go.pinniped.dev/internal/httputil/roundtripper"
 	"go.pinniped.dev/internal/kubeclient"
 	"go.pinniped.dev/internal/testutil"
@@ -305,20 +306,18 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 			Verb: "get", Group: "", Version: "v1", Resource: "namespaces",
 		})
 
-		// Get pods in concierge namespace and pick one.
+		// Get pods in supervisor namespace and pick one.
-		// this is for tests that require performing actions against a running pod. We use the concierge pod because we already have it handy.
+		// this is for tests that require performing actions against a running pod.
-		// We want to make sure it's a concierge pod (not cert agent), because we need to be able to port-forward a running port.
+		// We use the supervisor pod because we already have it handy and need to port-forward a running port.
-		pods, err := adminClient.CoreV1().Pods(env.ConciergeNamespace).List(ctx, metav1.ListOptions{})
+		// We avoid using the concierge for this because it requires TLS 1.3 which is not support by older versions of curl.
+		supervisorPods, err := adminClient.CoreV1().Pods(env.SupervisorNamespace).List(ctx,
+			metav1.ListOptions{LabelSelector: "deployment.pinniped.dev=supervisor"})
 		require.NoError(t, err)
-		require.Greater(t, len(pods.Items), 0)
+		require.NotEmpty(t, supervisorPods.Items, "could not find supervisor pods")
-		var conciergePod *corev1.Pod
+		supervisorPod := supervisorPods.Items[0]
-		for _, pod := range pods.Items {
+
-			pod := pod
+		// make sure the supervisor has a default TLS cert during this test so that it can handle a TLS connection
-			if !strings.Contains(pod.Name, "kube-cert-agent") {
+		createSupervisorDefaultTLSCertificateSecretIfNeeded(ctx, t)
-				conciergePod = &pod
-			}
-		}
-		require.NotNil(t, conciergePod, "could not find a concierge pod")
 
 		// Test that the user can perform basic actions through the client with their username and group membership
 		// influencing RBAC checks correctly.
@@ -346,7 +345,7 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 			// Run the kubectl port-forward command.
 			timeout, cancelFunc := context.WithTimeout(ctx, 2*time.Minute)
 			defer cancelFunc()
-			portForwardCmd, _, portForwardStderr := kubectlCommand(timeout, t, kubeconfigPath, envVarsWithProxy, "port-forward", "--namespace", env.ConciergeNamespace, conciergePod.Name, "10443:8443")
+			portForwardCmd, _, portForwardStderr := kubectlCommand(timeout, t, kubeconfigPath, envVarsWithProxy, "port-forward", "--namespace", supervisorPod.Namespace, supervisorPod.Name, "10443:8443")
 			portForwardCmd.Env = envVarsWithProxy
 
 			// Start, but don't wait for the command to finish.
@@ -366,7 +365,7 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 			defer cancelFunc()
 			startTime := time.Now()
 			for time.Now().Before(startTime.Add(70 * time.Second)) {
-				curlCmd := exec.CommandContext(timeout, "curl", "-k", "-sS", "https://127.0.0.1:10443") // -sS turns off the progressbar but still prints errors
+				curlCmd := exec.CommandContext(timeout, "curl", "-k", "-sS", "https://127.0.0.1:10443/healthz") // -sS turns off the progressbar but still prints errors
 				curlCmd.Stdout = &curlStdOut
 				curlCmd.Stderr = &curlStdErr
 				curlErr := curlCmd.Run()
@@ -382,7 +381,7 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 			// curl the endpoint once more, once 70 seconds has elapsed, to make sure the connection is still open.
 			timeout, cancelFunc = context.WithTimeout(ctx, 30*time.Second)
 			defer cancelFunc()
-			curlCmd := exec.CommandContext(timeout, "curl", "-k", "-sS", "https://127.0.0.1:10443") // -sS turns off the progressbar but still prints errors
+			curlCmd := exec.CommandContext(timeout, "curl", "-k", "-sS", "https://127.0.0.1:10443/healthz") // -sS turns off the progressbar but still prints errors
 			curlCmd.Stdout = &curlStdOut
 			curlCmd.Stderr = &curlStdErr
 			curlErr := curlCmd.Run()
@@ -392,9 +391,8 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 				t.Log("curlStdErr: " + curlStdErr.String())
 				t.Log("stdout: " + curlStdOut.String())
 			}
-			// We expect this to 403, but all we care is that it gets through.
 			require.NoError(t, curlErr)
-			require.Contains(t, curlStdOut.String(), `"forbidden: User \"system:anonymous\" cannot get path \"/\""`)
+			require.Contains(t, curlStdOut.String(), "okokokokok") // a few successful healthz responses
 		})
 
 		t.Run("kubectl port-forward and keeping the connection open for over a minute (idle)", func(t *testing.T) {
@@ -404,7 +402,7 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 			// Run the kubectl port-forward command.
 			timeout, cancelFunc := context.WithTimeout(ctx, 2*time.Minute)
 			defer cancelFunc()
-			portForwardCmd, _, portForwardStderr := kubectlCommand(timeout, t, kubeconfigPath, envVarsWithProxy, "port-forward", "--namespace", env.ConciergeNamespace, conciergePod.Name, "10444:8443")
+			portForwardCmd, _, portForwardStderr := kubectlCommand(timeout, t, kubeconfigPath, envVarsWithProxy, "port-forward", "--namespace", supervisorPod.Namespace, supervisorPod.Name, "10444:8443")
 			portForwardCmd.Env = envVarsWithProxy
 
 			// Start, but don't wait for the command to finish.
@@ -414,13 +412,13 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 				assert.EqualErrorf(t, portForwardCmd.Wait(), "signal: killed", `wanted "kubectl port-forward" to get signaled because context was cancelled (stderr: %q)`, portForwardStderr.String())
 			}()
 
-			// Wait to see if we time out. The default timeout is 60 seconds, but the server should recognize this this
+			// Wait to see if we time out. The default timeout is 60 seconds, but the server should recognize that this
 			// is going to be a long-running command and keep the connection open as long as the client stays connected.
 			time.Sleep(70 * time.Second)
 
 			timeout, cancelFunc = context.WithTimeout(ctx, 2*time.Minute)
 			defer cancelFunc()
-			curlCmd := exec.CommandContext(timeout, "curl", "-k", "-sS", "https://127.0.0.1:10444") // -sS turns off the progressbar but still prints errors
+			curlCmd := exec.CommandContext(timeout, "curl", "-k", "-sS", "https://127.0.0.1:10444/healthz") // -sS turns off the progressbar but still prints errors
 			var curlStdOut, curlStdErr bytes.Buffer
 			curlCmd.Stdout = &curlStdOut
 			curlCmd.Stderr = &curlStdErr
@@ -430,9 +428,8 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 				t.Log("curlStdErr: " + curlStdErr.String())
 				t.Log("stdout: " + curlStdOut.String())
 			}
-			// We expect this to 403, but all we care is that it gets through.
 			require.NoError(t, err)
-			require.Contains(t, curlStdOut.String(), `"forbidden: User \"system:anonymous\" cannot get path \"/\""`)
+			require.Equal(t, curlStdOut.String(), "ok")
 		})
 
 		t.Run("using and watching all the basic verbs", func(t *testing.T) {
@@ -760,7 +757,7 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 				clusterAdminCredentials, impersonationProxyURL, impersonationProxyCACertPEM, nil,
 			)
 			nestedImpersonationUIDOnly.Wrap(func(rt http.RoundTripper) http.RoundTripper {
-				return roundtripper.Func(func(r *http.Request) (*http.Response, error) {
+				return roundtripper.WrapFunc(rt, func(r *http.Request) (*http.Response, error) {
 					r.Header.Set("iMperSONATE-uid", "some-awesome-uid")
 					return rt.RoundTrip(r)
 				})
@@ -798,7 +795,7 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 				},
 			)
 			nestedImpersonationUID.Wrap(func(rt http.RoundTripper) http.RoundTripper {
-				return roundtripper.Func(func(r *http.Request) (*http.Response, error) {
+				return roundtripper.WrapFunc(rt, func(r *http.Request) (*http.Response, error) {
 					r.Header.Set("imperSONate-uiD", "some-fancy-uid")
 					return rt.RoundTrip(r)
 				})
@@ -1115,7 +1112,7 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 
 			// run the kubectl logs command
 			logLinesCount := 10
-			stdout, err = runKubectl(t, kubeconfigPath, envVarsWithProxy, "logs", "--namespace", conciergePod.Namespace, conciergePod.Name, fmt.Sprintf("--tail=%d", logLinesCount))
+			stdout, err = runKubectl(t, kubeconfigPath, envVarsWithProxy, "logs", "--namespace", supervisorPod.Namespace, supervisorPod.Name, fmt.Sprintf("--tail=%d", logLinesCount))
 			require.NoError(t, err, `"kubectl logs" failed`)
 			// Expect _approximately_ logLinesCount lines in the output
 			// (we can't match 100% exactly due to https://github.com/kubernetes/kubernetes/issues/72628).
@@ -1500,6 +1497,20 @@ func TestImpersonationProxy(t *testing.T) { //nolint:gocyclo // yeah, it's compl
 				})
 			})
 		})
+
+		t.Run("assert impersonator runs with secure TLS config", func(t *testing.T) {
+			parallelIfNotEKS(t)
+
+			cancelCtx, cancel := context.WithCancel(ctx)
+			t.Cleanup(cancel)
+
+			startKubectlPortForward(cancelCtx, t, "10445", "443", env.ConciergeAppName+"-proxy", env.ConciergeNamespace)
+
+			stdout, stderr := runNmapSSLEnum(t, "127.0.0.1", 10445)
+
+			require.Empty(t, stderr)
+			require.Contains(t, stdout, getExpectedCiphers(ptls.Default), "stdout:\n%s", stdout)
+		})
 	})
 
 	t.Run("assert correct impersonator service account is being used", func(t *testing.T) {
@@ -1956,7 +1967,7 @@ func performImpersonatorDiscovery(ctx context.Context, t *testing.T, env *testli
 	// probe each pod directly for readiness since the concierge status is a lie - it just means a single pod is ready
 	testlib.RequireEventually(t, func(requireEventually *require.Assertions) {
 		pods, err := adminClient.CoreV1().Pods(env.ConciergeNamespace).List(ctx,
-			metav1.ListOptions{LabelSelector: "app=" + env.ConciergeAppName + ",!kube-cert-agent.pinniped.dev"}) // TODO replace with deployment.pinniped.dev=concierge
+			metav1.ListOptions{LabelSelector: "deployment.pinniped.dev=concierge"})
 		requireEventually.NoError(err)
 		requireEventually.Len(pods.Items, 2) // has to stay in sync with the defaults in our YAML
 
@@ -2373,7 +2384,7 @@ func getCredForConfig(t *testing.T, config *rest.Config) *loginv1alpha1.ClusterC
 	config = rest.CopyConfig(config)
 
 	config.Wrap(func(rt http.RoundTripper) http.RoundTripper {
-		return roundtripper.Func(func(req *http.Request) (*http.Response, error) {
+		return roundtripper.WrapFunc(rt, func(req *http.Request) (*http.Response, error) {
 			resp, err := rt.RoundTrip(req)
 
 			r := req

test/integration/ldap_client_test.go

@@ -759,8 +759,6 @@ func startLongRunningCommandAndWaitForInitialOutput(
 	cmd := exec.CommandContext(ctx, command, args...)
 
 	var stdoutBuf, stderrBuf syncBuffer
-	cmd.Stdout = &stdoutBuf
-	cmd.Stderr = &stderrBuf
 	cmd.Stdout = io.MultiWriter(os.Stdout, &stdoutBuf)
 	cmd.Stderr = io.MultiWriter(os.Stderr, &stderrBuf)
 

test/integration/securetls_test.go

@@ -0,0 +1,256 @@
+// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package integration
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"os/exec"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"go.pinniped.dev/internal/crypto/ptls"
+	"go.pinniped.dev/internal/testutil/tlsserver"
+	"go.pinniped.dev/test/testlib"
+)
+
+// TLS checks safe to run in parallel with serial tests, see main_test.go.
+func TestSecureTLSPinnipedCLIToKAS_Parallel(t *testing.T) {
+	_ = testlib.IntegrationEnv(t)
+
+	server := tlsserver.TLSTestServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		tlsserver.AssertTLS(t, r, ptls.Secure) // pinniped CLI uses ptls.Secure when talking to KAS
+		w.Header().Set("content-type", "application/json")
+		fmt.Fprint(w, `{"kind":"TokenCredentialRequest","apiVersion":"login.concierge.pinniped.dev/v1alpha1",`+
+			`"status":{"credential":{"token":"some-fancy-token"}}}`)
+	}), tlsserver.RecordTLSHello)
+
+	ca := tlsserver.TLSTestServerCA(server)
+
+	pinnipedExe := testlib.PinnipedCLIPath(t)
+
+	stdout, stderr := runPinnipedCLI(t, nil, pinnipedExe, "login", "static",
+		"--token", "does-not-matter",
+		"--concierge-authenticator-type", "webhook",
+		"--concierge-authenticator-name", "does-not-matter",
+		"--concierge-ca-bundle-data", base64.StdEncoding.EncodeToString(ca),
+		"--concierge-endpoint", server.URL,
+		"--enable-concierge",
+		"--credential-cache", "",
+	)
+
+	require.Empty(t, stderr)
+	require.Equal(t, `{"kind":"ExecCredential","apiVersion":"client.authentication.k8s.io/v1beta1",`+
+		`"spec":{"interactive":false},"status":{"expirationTimestamp":null,"token":"some-fancy-token"}}
+`, stdout)
+}
+
+// TLS checks safe to run in parallel with serial tests, see main_test.go.
+func TestSecureTLSPinnipedCLIToSupervisor_Parallel(t *testing.T) {
+	_ = testlib.IntegrationEnv(t)
+
+	server := tlsserver.TLSTestServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		tlsserver.AssertTLS(t, r, ptls.Default) // pinniped CLI uses ptls.Default when talking to supervisor
+		w.Header().Set("content-type", "application/json")
+		fmt.Fprint(w, `{"issuer":"https://not-a-good-issuer"}`)
+	}), tlsserver.RecordTLSHello)
+
+	ca := tlsserver.TLSTestServerCA(server)
+
+	pinnipedExe := testlib.PinnipedCLIPath(t)
+
+	stdout, stderr := runPinnipedCLI(&fakeT{T: t}, nil, pinnipedExe, "login", "oidc",
+		"--ca-bundle-data", base64.StdEncoding.EncodeToString(ca),
+		"--issuer", server.URL,
+		"--credential-cache", "",
+		"--upstream-identity-provider-flow", "cli_password",
+		"--upstream-identity-provider-name", "does-not-matter",
+		"--upstream-identity-provider-type", "oidc",
+	)
+
+	require.Equal(t, `Error: could not complete Pinniped login: could not perform OIDC discovery for "`+
+		server.URL+`": oidc: issuer did not match the issuer returned by provider, expected "`+
+		server.URL+`" got "https://not-a-good-issuer"
+`, stderr)
+	require.Empty(t, stdout)
+}
+
+// TLS checks safe to run in parallel with serial tests, see main_test.go.
+func TestSecureTLSConciergeAggregatedAPI_Parallel(t *testing.T) {
+	env := testlib.IntegrationEnv(t)
+
+	cancelCtx, cancel := context.WithCancel(context.Background())
+	t.Cleanup(cancel)
+
+	startKubectlPortForward(cancelCtx, t, "10446", "443", env.ConciergeAppName+"-api", env.ConciergeNamespace)
+
+	stdout, stderr := runNmapSSLEnum(t, "127.0.0.1", 10446)
+
+	require.Empty(t, stderr)
+	require.Contains(t, stdout, getExpectedCiphers(ptls.Secure), "stdout:\n%s", stdout)
+}
+
+func TestSecureTLSSupervisor(t *testing.T) { // does not run in parallel because of the createSupervisorDefaultTLSCertificateSecretIfNeeded call
+	env := testlib.IntegrationEnv(t)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	t.Cleanup(cancel)
+
+	// make sure the supervisor has a default TLS cert during this test so that it can handle a TLS connection
+	createSupervisorDefaultTLSCertificateSecretIfNeeded(ctx, t)
+
+	startKubectlPortForward(ctx, t, "10447", "443", env.SupervisorAppName+"-nodeport", env.SupervisorNamespace)
+
+	stdout, stderr := runNmapSSLEnum(t, "127.0.0.1", 10447)
+
+	// supervisor's cert is ECDSA
+	defaultECDSAOnly := func(rootCAs *x509.CertPool) *tls.Config {
+		c := ptls.Default(rootCAs)
+		ciphers := make([]uint16, 0, len(c.CipherSuites)/2)
+		for _, id := range c.CipherSuites {
+			id := id
+			if !strings.Contains(tls.CipherSuiteName(id), "_ECDSA_") {
+				continue
+			}
+			ciphers = append(ciphers, id)
+		}
+		c.CipherSuites = ciphers
+		return c
+	}
+
+	require.Empty(t, stderr)
+	require.Contains(t, stdout, getExpectedCiphers(defaultECDSAOnly), "stdout:\n%s", stdout)
+}
+
+type fakeT struct {
+	*testing.T
+}
+
+func (t *fakeT) FailNow() {
+	t.Errorf("fakeT ignored FailNow")
+}
+
+func (t *fakeT) Errorf(format string, args ...interface{}) {
+	t.Cleanup(func() {
+		if !t.Failed() {
+			return
+		}
+		t.Logf("reporting previously ignored errors since main test failed:\n"+format, args...)
+	})
+}
+
+func runNmapSSLEnum(t *testing.T, host string, port uint16) (string, string) {
+	t.Helper()
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+
+	version, err := exec.CommandContext(ctx, "nmap", "-V").CombinedOutput()
+	require.NoError(t, err)
+
+	versionMatches := regexp.MustCompile(`Nmap version 7\.(?P<minor>\d+)`).FindStringSubmatch(string(version))
+	require.Len(t, versionMatches, 2)
+	minorVersion, err := strconv.Atoi(versionMatches[1])
+	require.NoError(t, err)
+	require.GreaterOrEqual(t, minorVersion, 92, "nmap >= 7.92.x is required")
+
+	var stdout, stderr bytes.Buffer
+	//nolint:gosec // we are not performing malicious argument injection against ourselves
+	cmd := exec.CommandContext(ctx, "nmap", "--script", "ssl-enum-ciphers",
+		"-p", strconv.FormatUint(uint64(port), 10),
+		host,
+	)
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+
+	require.NoErrorf(t, cmd.Run(), "stderr:\n%s\n\nstdout:\n%s\n\n", stderr.String(), stdout.String())
+
+	return stdout.String(), stderr.String()
+}
+
+func getExpectedCiphers(configFunc ptls.ConfigFunc) string {
+	config := configFunc(nil)
+	secureConfig := ptls.Secure(nil)
+
+	skip12 := config.MinVersion == secureConfig.MinVersion
+
+	var tls12Bit, tls13Bit string
+
+	if !skip12 {
+		sort.SliceStable(config.CipherSuites, func(i, j int) bool {
+			a := tls.CipherSuiteName(config.CipherSuites[i])
+			b := tls.CipherSuiteName(config.CipherSuites[j])
+
+			ok1 := strings.Contains(a, "_ECDSA_")
+			ok2 := strings.Contains(b, "_ECDSA_")
+
+			if ok1 && ok2 {
+				return false
+			}
+
+			return ok1
+		})
+
+		var s strings.Builder
+		for i, id := range config.CipherSuites {
+			s.WriteString(fmt.Sprintf(tls12Item, tls.CipherSuiteName(id)))
+			if i == len(config.CipherSuites)-1 {
+				break
+			}
+			s.WriteString("\n")
+		}
+		tls12Bit = fmt.Sprintf(tls12Base, s.String())
+	}
+
+	var s strings.Builder
+	for i, id := range secureConfig.CipherSuites {
+		s.WriteString(fmt.Sprintf(tls13Item, strings.Replace(tls.CipherSuiteName(id), "TLS_", "TLS_AKE_WITH_", 1)))
+		if i == len(secureConfig.CipherSuites)-1 {
+			break
+		}
+		s.WriteString("\n")
+	}
+	tls13Bit = fmt.Sprintf(tls13Base, s.String())
+
+	return fmt.Sprintf(baseItem, tls12Bit, tls13Bit)
+}
+
+const (
+	// this surrounds the tls 1.2 and 1.3 text in a way that guarantees that other TLS versions are not supported.
+	baseItem = `/tcp open  unknown
+| ssl-enum-ciphers: %s%s
+|_  least strength: A
+
+Nmap done: 1 IP address (1 host up) scanned in`
+
+	// the "cipher preference: client" bit a bug in nmap.
+	// https://github.com/nmap/nmap/issues/1691#issuecomment-536919978
+	tls12Base = `
+|   TLSv1.2: 
+|     ciphers: 
+%s
+|     compressors: 
+|       NULL
+|     cipher preference: client`
+
+	tls13Base = `
+|   TLSv1.3: 
+|     ciphers: 
+%s
+|     cipher preference: server`
+
+	tls12Item = `|       %s (secp256r1) - A`
+	tls13Item = `|       %s (ecdh_x25519) - A`
+)

test/integration/supervisor_discovery_test.go

@@ -320,6 +320,22 @@ func createTLSCertificateSecret(ctx context.Context, t *testing.T, ns string, ho
 	return ca
 }
 
+func createSupervisorDefaultTLSCertificateSecretIfNeeded(ctx context.Context, t *testing.T) {
+	env := testlib.IntegrationEnv(t)
+	adminClient := testlib.NewKubernetesClientset(t)
+
+	ns := env.SupervisorNamespace
+	name := defaultTLSCertSecretName(env)
+
+	_, err := adminClient.CoreV1().Secrets(ns).Get(ctx, name, metav1.GetOptions{})
+
+	if k8serrors.IsNotFound(err) {
+		_ = createTLSCertificateSecret(ctx, t, ns, "cert-hostname-doesnt-matter", nil, name, adminClient)
+	} else {
+		require.NoError(t, err)
+	}
+}
+
 func temporarilyRemoveAllFederationDomainsAndDefaultTLSCertSecret(
 	ctx context.Context,
 	t *testing.T,

test/testlib/client.go

@@ -132,7 +132,7 @@ func newClientsetWithConfig(t *testing.T, config *rest.Config) kubernetes.Interf
 func NewAnonymousClientRestConfig(t *testing.T) *rest.Config {
 	t.Helper()
 
-	return rest.AnonymousClientConfig(NewClientConfig(t))
+	return kubeclient.SecureAnonymousClientConfig(NewClientConfig(t))
 }
 
 // Starting with an anonymous client config, add a cert and key to use for authentication in the API server.