Disable HTTP/2 for webhoook by updating Knative

go.mod

@@ -32,7 +32,7 @@ require (
 	k8s.io/apimachinery v0.27.4
 	k8s.io/client-go v1.5.2
 	k8s.io/code-generator v0.27.1
-	knative.dev/pkg v0.0.0-20230718152110-aef227e72ead
+	knative.dev/pkg v0.0.0-20231023150739-56bfe0dd9626
 	sigs.k8s.io/yaml v1.4.0
 )
 

go.sum

@@ -2273,8 +2273,8 @@ k8s.io/utils v0.0.0-20230726121419-3b25d923346b h1:sgn3ZU783SCgtaSJjpcVVlRqd6GSn
 k8s.io/utils v0.0.0-20230726121419-3b25d923346b/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
 knative.dev/eventing v0.38.0 h1:n6/k9IJ1kOvpZx4CMLqa1FG7g2iBiyKXwBu1Fy/81q4=
 knative.dev/networking v0.0.0-20220404212543-dde40b019aff h1:pqzWi29qb44TY+5xtc9vty4mSyUYvojXZGCp0y/91eo=
-knative.dev/pkg v0.0.0-20230718152110-aef227e72ead h1:2dDzorpKuVZW3Qp7TbirMMq16FbId8f6bacQFX8jXLw=
-knative.dev/pkg v0.0.0-20230718152110-aef227e72ead/go.mod h1:WmrwRV/P+hGHoMraAEfwg6ec+fBTf+Obu41v354Iabc=
+knative.dev/pkg v0.0.0-20231023150739-56bfe0dd9626 h1:qFE+UDBRg6cpF5LbA0sv1XK4XZ36Z7aTRCa+HcuxnNQ=
+knative.dev/pkg v0.0.0-20231023150739-56bfe0dd9626/go.mod h1:g+UCgSKQ2f15kHYu/V3CPtoKo5F1x/2Y1ot0NSK7gA0=
 knative.dev/serving v0.30.1-0.20220402124840-21c05dc9d9a4 h1:iRFWsFKsA5ddhi+eKZVJdf8gPBomTfjIyRAKk9Uh7Ko=
 rsc.io/binaryregexp v0.2.0/go.mod h1:qTv7/COck+e2FymRvadv62gMdZztPaShugOCi3I+8D8=
 rsc.io/quote/v3 v3.1.0/go.mod h1:yEA65RcK8LyAZtP9Kv3t0HmxON59tX3rD+tICJqUlj0=

vendor/knative.dev/pkg/webhook/webhook.go

@@ -74,6 +74,17 @@ type Options struct {
 	// ControllerOptions encapsulates options for creating a new controller,
 	// including throttling and stats behavior.
 	ControllerOptions *controller.ControllerOptions
+
+	// EnableHTTP2 enables HTTP2 for webhooks.
+	// Mitigate CVE-2023-44487 by disabling HTTP2 by default until the Go
+	// standard library and golang.org/x/net are fully fixed.
+	// Right now, it is possible for authenticated and unauthenticated users to
+	// hold open HTTP2 connections and consume huge amounts of memory.
+	// See:
+	// * https://github.com/kubernetes/kubernetes/pull/121120
+	// * https://github.com/kubernetes/kubernetes/issues/121197
+	// * https://github.com/golang/go/issues/63417#issuecomment-1758858612
+	EnableHTTP2 bool
 }
 
 // Operation is the verb being operated on
@@ -237,12 +248,19 @@ func (wh *Webhook) Run(stop <-chan struct{}) error {
 		QuietPeriod: wh.Options.GracePeriod,
 	}
 
+	// If TLSNextProto is not nil, HTTP/2 support is not enabled automatically.
+	nextProto := map[string]func(*http.Server, *tls.Conn, http.Handler){}
+	if wh.Options.EnableHTTP2 {
+		nextProto = nil
+	}
+
 	server := &http.Server{
 		ErrorLog:          log.New(&zapWrapper{logger}, "", 0),
 		Handler:           drainer,
 		Addr:              fmt.Sprint(":", wh.Options.Port),
 		TLSConfig:         wh.tlsConfig,
 		ReadHeaderTimeout: time.Minute, //https://medium.com/a-journey-with-go/go-understand-and-mitigate-slowloris-attack-711c1b1403f6
+		TLSNextProto:      nextProto,
 	}
 
 	var serve = server.ListenAndServe

vendor/modules.txt

@@ -2163,7 +2163,7 @@ k8s.io/utils/pointer
 k8s.io/utils/ptr
 k8s.io/utils/strings/slices
 k8s.io/utils/trace
-# knative.dev/pkg v0.0.0-20230718152110-aef227e72ead
+# knative.dev/pkg v0.0.0-20231023150739-56bfe0dd9626
 ## explicit; go 1.18
 knative.dev/pkg/apis
 knative.dev/pkg/apis/duck