Add Cache-Control, Pragma, Expires, and X-DNS-Prefetch-Control headers

Signed-off-by: Margo Crawford <margaretc@vmware.com>

internal/httputil/securityheader/securityheader.go

@@ -9,12 +9,22 @@ import "net/http"
 // Wrap the provided http.Handler so it sets appropriate security-related response headers.
 func Wrap(wrapped http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		wrapped.ServeHTTP(w, r)
 		h := w.Header()
 		h.Set("Content-Security-Policy", "default-src 'none'; frame-ancestors 'none'")
 		h.Set("X-Frame-Options", "DENY")
 		h.Set("X-XSS-Protection", "1; mode=block")
 		h.Set("X-Content-Type-Options", "nosniff")
 		h.Set("Referrer-Policy", "no-referrer")
-		wrapped.ServeHTTP(w, r)
+		h.Set("X-DNS-Prefetch-Control", "off")
+
+		// first overwrite existing Cache-Control header with Set, then append more headers with Add
+		h.Set("Cache-Control", "no-cache")
+		h.Add("Cache-Control", "no-store")
+		h.Add("Cache-Control", "max-age=0")
+		h.Add("Cache-Control", "must-revalidate")
+
+		h.Set("Pragma", "no-cache")
+		h.Set("Expires", "0")
 	})
 }

internal/httputil/securityheader/securityheader_test.go

@@ -26,5 +26,9 @@ func TestWrap(t *testing.T) {
 		"X-Content-Type-Options":  []string{"nosniff"},
 		"X-Frame-Options":         []string{"DENY"},
 		"X-Xss-Protection":        []string{"1; mode=block"},
+		"X-Dns-Prefetch-Control":  []string{"off"},
+		"Cache-Control":           []string{"no-cache", "no-store", "max-age=0", "must-revalidate"},
+		"Pragma":                  []string{"no-cache"},
+		"Expires":                 []string{"0"},
 	}, rec.Header())
 }

internal/oidc/auth/auth_handler.go

@@ -16,6 +16,7 @@ import (
 	"golang.org/x/oauth2"
 
 	"go.pinniped.dev/internal/httputil/httperr"
+	"go.pinniped.dev/internal/httputil/securityheader"
 	"go.pinniped.dev/internal/oidc"
 	"go.pinniped.dev/internal/oidc/csrftoken"
 	"go.pinniped.dev/internal/oidc/provider"
@@ -34,7 +35,7 @@ func NewHandler(
 	upstreamStateEncoder oidc.Encoder,
 	cookieCodec oidc.Codec,
 ) http.Handler {
-	return httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
+	return securityheader.Wrap(httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
 		if r.Method != http.MethodPost && r.Method != http.MethodGet {
 			// https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest
 			// Authorization Servers MUST support the use of the HTTP GET and POST methods defined in
@@ -142,7 +143,7 @@ func NewHandler(
 		)
 
 		return nil
-	})
+	}))
 }
 
 func readCSRFCookie(r *http.Request, codec oidc.Decoder) csrftoken.CSRFToken {

internal/oidc/auth/auth_handler_test.go

@@ -773,6 +773,7 @@ func TestAuthorizationEndpoint(t *testing.T) {
 
 		require.Equal(t, test.wantStatus, rsp.Code)
 		testutil.RequireEqualContentType(t, rsp.Header().Get("Content-Type"), test.wantContentType)
+		testutil.RequireSecurityHeaders(t, rsp)
 
 		actualLocation := rsp.Header().Get("Location")
 		if test.wantLocationHeader != "" {

internal/oidc/callback/callback_handler.go

@@ -17,6 +17,7 @@ import (
 	"github.com/ory/fosite/token/jwt"
 
 	"go.pinniped.dev/internal/httputil/httperr"
+	"go.pinniped.dev/internal/httputil/securityheader"
 	"go.pinniped.dev/internal/oidc"
 	"go.pinniped.dev/internal/oidc/csrftoken"
 	"go.pinniped.dev/internal/oidc/provider"
@@ -45,7 +46,7 @@ func NewHandler(
 	stateDecoder, cookieDecoder oidc.Decoder,
 	redirectURI string,
 ) http.Handler {
-	return httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
+	return securityheader.Wrap(httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
 		state, err := validateRequest(r, stateDecoder, cookieDecoder)
 		if err != nil {
 			return err
@@ -108,7 +109,7 @@ func NewHandler(
 		oauthHelper.WriteAuthorizeResponse(w, authorizeRequester, authorizeResponder)
 
 		return nil
-	})
+	}))
 }
 
 func authcode(r *http.Request) string {

internal/oidc/callback/callback_handler_test.go

@@ -477,6 +477,8 @@ func TestCallbackEndpoint(t *testing.T) {
 			t.Logf("response: %#v", rsp)
 			t.Logf("response body: %q", rsp.Body.String())
 
+			testutil.RequireSecurityHeaders(t, rsp)
+
 			if test.wantExchangeAndValidateTokensCall != nil {
 				require.Equal(t, 1, test.idp.ExchangeAuthcodeAndValidateTokensCallCount())
 				test.wantExchangeAndValidateTokensCall.Ctx = req.Context()

internal/testutil/assertions.go

@@ -6,6 +6,7 @@ package testutil
 import (
 	"context"
 	"mime"
+	"net/http/httptest"
 	"testing"
 	"time"
 
@@ -52,3 +53,15 @@ func RequireNumberOfSecretsMatchingLabelSelector(t *testing.T, secrets v1.Secret
 	require.NoError(t, err)
 	require.Len(t, storedAuthcodeSecrets.Items, expectedNumberOfSecrets)
 }
+
+func RequireSecurityHeaders(t *testing.T, response *httptest.ResponseRecorder) {
+	require.Equal(t, "default-src 'none'; frame-ancestors 'none'", response.Header().Get("Content-Security-Policy"))
+	require.Equal(t, "DENY", response.Header().Get("X-Frame-Options"))
+	require.Equal(t, "1; mode=block", response.Header().Get("X-XSS-Protection"))
+	require.Equal(t, "nosniff", response.Header().Get("X-Content-Type-Options"))
+	require.Equal(t, "no-referrer", response.Header().Get("Referrer-Policy"))
+	require.Equal(t, "off", response.Header().Get("X-DNS-Prefetch-Control"))
+	require.ElementsMatch(t, []string{"no-cache", "no-store", "max-age=0", "must-revalidate"}, response.Header().Values("Cache-Control"))
+	require.Equal(t, "no-cache", response.Header().Get("Pragma"))
+	require.Equal(t, "0", response.Header().Get("Expires"))
+}