feat: introduce custom response header limit

Add a new property to configure the response header limit of the transport used to send requests to route services and backends. Resolves: cloudfoundry/routing-release#309
cloudfoundry · Nov 18, 2024 · 8528055 · 8528055
1 parent 35e4728
commit 8528055
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Showing 4 changed files with 55 additions and 27 deletions.
diff --git a/config/config.go b/config/config.go
@@ -461,6 +461,7 @@ type Config struct {
 	MaxIdleConns                 int  `yaml:"max_idle_conns,omitempty"`
 	MaxIdleConnsPerHost          int  `yaml:"max_idle_conns_per_host,omitempty"`
 	MaxRequestHeaderBytes        int  `yaml:"max_request_header_bytes"`
+	MaxResponseHeaderBytes       int  `yaml:"max_response_header_bytes"`
 	KeepAlive100ContinueRequests bool `yaml:"keep_alive_100_continue_requests"`
 
 	HTTPRewrite HTTPRewrite `yaml:"http_rewrite,omitempty"`

diff --git a/integration/header_test.go b/integration/header_test.go
@@ -5,6 +5,7 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"strings"
 
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
@@ -197,4 +198,27 @@ var _ = Describe("Headers", func() {
 			Expect(resp.Header.Get(HeaderKeySignature)).To(BeEmpty())
 		})
 	})
+
+	Context("Header Limits", func() {
+		Context("when a response header size limit is configured", func() {
+			BeforeEach(func() {
+				testApp = NewUnstartedTestApp(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+					w.Header().Set("Too-Large", strings.Repeat("0123456789", 10))
+					w.WriteHeader(200)
+				}))
+				testState.cfg.MaxResponseHeaderBytes = 80
+				testState.StartGorouterOrFail()
+				testApp.Start()
+				testState.register(testApp.Server, testAppRoute)
+			})
+
+			It("fails with 502 when the app exceeds the limit", func() {
+				req := testState.newRequest(fmt.Sprintf("http://%s", testAppRoute))
+				resp, err := testState.client.Do(req)
+				Expect(err).NotTo(HaveOccurred())
+				Expect(resp.StatusCode).To(Equal(http.StatusBadGateway))
+				Expect(resp.Header).To(HaveKeyWithValue("X-Cf-Routererror", []string{"endpoint_failure (net/http: HTTP/1.x transport connection broken: net/http: server response headers exceeded 80 bytes; aborted)"}))
+			})
+		})
+	})
 })
diff --git a/proxy/proxy.go b/proxy/proxy.go
@@ -84,25 +84,27 @@ func NewProxy(
 
 	roundTripperFactory := &round_tripper.FactoryImpl{
 		BackendTemplate: &http.Transport{
-			DialContext:           dialer.DialContext,
-			DisableKeepAlives:     cfg.DisableKeepAlives,
-			MaxIdleConns:          cfg.MaxIdleConns,
-			IdleConnTimeout:       90 * time.Second, // setting the value to golang default transport
-			MaxIdleConnsPerHost:   cfg.MaxIdleConnsPerHost,
-			DisableCompression:    true,
-			TLSClientConfig:       backendTLSConfig,
-			TLSHandshakeTimeout:   cfg.TLSHandshakeTimeout,
-			ExpectContinueTimeout: 1 * time.Second,
+			DialContext:            dialer.DialContext,
+			DisableKeepAlives:      cfg.DisableKeepAlives,
+			MaxIdleConns:           cfg.MaxIdleConns,
+			IdleConnTimeout:        90 * time.Second, // setting the value to golang default transport
+			MaxIdleConnsPerHost:    cfg.MaxIdleConnsPerHost,
+			DisableCompression:     true,
+			TLSClientConfig:        backendTLSConfig,
+			TLSHandshakeTimeout:    cfg.TLSHandshakeTimeout,
+			ExpectContinueTimeout:  1 * time.Second,
+			MaxResponseHeaderBytes: int64(cfg.MaxResponseHeaderBytes),
 		},
 		RouteServiceTemplate: &http.Transport{
-			DialContext:           dialer.DialContext,
-			DisableKeepAlives:     cfg.DisableKeepAlives,
-			MaxIdleConns:          cfg.MaxIdleConns,
-			IdleConnTimeout:       90 * time.Second, // setting the value to golang default transport
-			MaxIdleConnsPerHost:   cfg.MaxIdleConnsPerHost,
-			DisableCompression:    true,
-			TLSClientConfig:       routeServiceTLSConfig,
-			ExpectContinueTimeout: 1 * time.Second,
+			DialContext:            dialer.DialContext,
+			DisableKeepAlives:      cfg.DisableKeepAlives,
+			MaxIdleConns:           cfg.MaxIdleConns,
+			IdleConnTimeout:        90 * time.Second, // setting the value to golang default transport
+			MaxIdleConnsPerHost:    cfg.MaxIdleConnsPerHost,
+			DisableCompression:     true,
+			TLSClientConfig:        routeServiceTLSConfig,
+			ExpectContinueTimeout:  1 * time.Second,
+			MaxResponseHeaderBytes: int64(cfg.MaxResponseHeaderBytes),
 		},
 		IsInstrumented: cfg.SendHttpStartStopClientEvent,
 	}

diff --git a/proxy/round_tripper/dropsonde_round_tripper.go b/proxy/round_tripper/dropsonde_round_tripper.go
@@ -45,16 +45,17 @@ func (t *FactoryImpl) New(expectedServerName string, isRouteService bool, isHttp
 	customTLSConfig := utils.TLSConfigWithServerName(expectedServerName, template.TLSClientConfig, isRouteService)
 
 	newTransport := &http.Transport{
-		DialContext:           template.DialContext,
-		DisableKeepAlives:     template.DisableKeepAlives,
-		MaxIdleConns:          template.MaxIdleConns,
-		IdleConnTimeout:       template.IdleConnTimeout,
-		MaxIdleConnsPerHost:   template.MaxIdleConnsPerHost,
-		DisableCompression:    template.DisableCompression,
-		TLSClientConfig:       customTLSConfig,
-		TLSHandshakeTimeout:   template.TLSHandshakeTimeout,
-		ForceAttemptHTTP2:     isHttp2,
-		ExpectContinueTimeout: template.ExpectContinueTimeout,
+		DialContext:            template.DialContext,
+		DisableKeepAlives:      template.DisableKeepAlives,
+		MaxIdleConns:           template.MaxIdleConns,
+		IdleConnTimeout:        template.IdleConnTimeout,
+		MaxIdleConnsPerHost:    template.MaxIdleConnsPerHost,
+		DisableCompression:     template.DisableCompression,
+		TLSClientConfig:        customTLSConfig,
+		TLSHandshakeTimeout:    template.TLSHandshakeTimeout,
+		ForceAttemptHTTP2:      isHttp2,
+		ExpectContinueTimeout:  template.ExpectContinueTimeout,
+		MaxResponseHeaderBytes: template.MaxResponseHeaderBytes,
 	}
 	if t.IsInstrumented {
 		return NewDropsondeRoundTripper(newTransport)