CVE-2024-34084

@@ -21,8 +21,10 @@ import (
 	"database/sql"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"os"
+	"strings"
 	"testing"
 	"time"
 
@@ -436,6 +438,73 @@ func (s *UnitTestSuite) TestNoopWebhookHandler() {
 	assert.Equal(t, http.StatusOK, resp.StatusCode, "unexpected status code")
 }
 
+func (s *UnitTestSuite) TestHandleWebHookWithTooLargeRequest() {
+	t := s.T()
+	t.Parallel()
+
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+
+	mockStore := mockdb.NewMockStore(ctrl)
+	srv, evt := newDefaultServer(t, mockStore, nil)
+	defer evt.Close()
+
+	pq := testqueue.NewPassthroughQueue(t)
+	queued := pq.GetQueue()
+
+	evt.Register(events.TopicQueueEntityEvaluate, pq.Pass)
+
+	go func() {
+		err := evt.Run(context.Background())
+		require.NoError(t, err, "failed to run eventer")
+	}()
+
+	<-evt.Running()
+
+	hook := withMaxSizeMiddleware(srv.HandleGitHubWebHook())
+	port, err := rand.GetRandomPort()
+	if err != nil {
+		t.Fatal(err)
+	}
+	addr := fmt.Sprintf("localhost:%d", port)
+	server := &http.Server{
+		Addr:              fmt.Sprintf(":%d", port),
+		Handler:           hook,
+		ReadHeaderTimeout: 1 * time.Second,
+	}
+	go server.ListenAndServe()
+
+	event := github.PackageEvent{
+		Action: github.String("published"),
+		Repo: &github.Repository{
+			ID:   github.Int64(12345),
+			Name: github.String("stacklok/minder"),
+		},
+		Org: &github.Organization{
+			Login: github.String("stacklok"),
+		},
+	}
+	packageJson, err := json.Marshal(event)
+	require.NoError(t, err, "failed to marshal package event")
+
+	maliciousBody := strings.NewReader(strings.Repeat("1337", 1000000000))
+	maliciousBodyReader := io.MultiReader(maliciousBody, maliciousBody, maliciousBody, maliciousBody, maliciousBody)
+	_ = packageJson
+
+	client := &http.Client{}
+	req, err := http.NewRequest("POST", fmt.Sprintf("http://%s", addr), maliciousBodyReader)
+	require.NoError(t, err, "failed to create request")
+
+	req.Header.Add("X-GitHub-Event", "meta")
+	req.Header.Add("X-GitHub-Delivery", "12345")
+	req.Header.Add("Content-Type", "application/json")
+	resp, err := httpDoWithRetry(client, req)
+	require.NoError(t, err, "failed to make request")
+	// We expect OK since we don't want to leak information about registered repositories
+	require.Equal(t, http.StatusBadRequest, resp.StatusCode, "unexpected status code")
+	assert.Len(t, queued, 0)
+}
+
 func TestAll(t *testing.T) {
 	t.Parallel()
 

@@ -70,6 +70,10 @@ const metricsPath = "/metrics"
 
 var (
 	readHeaderTimeout = 2 * time.Second
+
+	// RequestBodyMaxBytes is the maximum number of bytes that can be read from a request body
+	// We limit to 2MB for now
+	RequestBodyMaxBytes int64 = 2 << 20
 )
 
 // Server represents the controlplane server
@@ -316,10 +320,10 @@ func (s *Server) StartHTTPServer(ctx context.Context) error {
 		return fmt.Errorf("failed to register GitHub App callback handler: %w", err)
 	}
 
-	mux.Handle("/", s.handlerWithHTTPMiddleware(gwmux))
-	mux.Handle("/api/v1/webhook/", mw(s.HandleGitHubWebHook()))
-	mux.Handle("/api/v1/ghapp/", mw(s.HandleGitHubAppWebhook()))
-	mux.Handle("/api/v1/gh-marketplace/", mw(s.NoopWebhookHandler()))
+	mux.Handle("/", withMaxSizeMiddleware(s.handlerWithHTTPMiddleware(gwmux)))
+	mux.Handle("/api/v1/webhook/", mw(withMaxSizeMiddleware(s.HandleGitHubWebHook())))
+	mux.Handle("/api/v1/ghapp/", mw(withMaxSizeMiddleware(s.HandleGitHubAppWebhook())))
+	mux.Handle("/api/v1/gh-marketplace/", mw(withMaxSizeMiddleware(s.NoopWebhookHandler())))
 	mux.Handle("/static/", fs)
 
 	errch := make(chan error)
@@ -451,3 +455,10 @@ func shutdownHandler(component string, sdf shutdowner) {
 		log.Fatal().Msgf("error shutting down '%s': %+v", component, err)
 	}
 }
+
+func withMaxSizeMiddleware(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		r.Body = http.MaxBytesReader(w, r.Body, RequestBodyMaxBytes)
+		h.ServeHTTP(w, r)
+	})
+}