fix(chisel): fix a nil pointer dereference EE-6481 (#10871)

api/chisel/service.go

@@ -21,6 +21,7 @@ const (
 	tunnelCleanupInterval = 10 * time.Second
 	requiredTimeout       = 15 * time.Second
 	activeTimeout         = 4*time.Minute + 30*time.Second
+	pingTimeout           = 3 * time.Second
 )
 
 // Service represents a service to manage the state of multiple reverse tunnels.
@@ -59,14 +60,18 @@ func (service *Service) pingAgent(endpointID portainer.EndpointID) error {
 	}
 
 	httpClient := &http.Client{
-		Timeout: 3 * time.Second,
+		Timeout: pingTimeout,
 	}
 
 	resp, err := httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+
 	io.Copy(io.Discard, resp.Body)
 	resp.Body.Close()
 
-	return err
+	return nil
 }
 
 // KeepTunnelAlive keeps the tunnel of the given environment for maxAlive duration, or until ctx is done

api/chisel/service_test.go

@@ -0,0 +1,39 @@
+package chisel
+
+import (
+	"net"
+	"net/http"
+	"testing"
+	"time"
+
+	portainer "github.com/portainer/portainer/api"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPingAgentPanic(t *testing.T) {
+	endpointID := portainer.EndpointID(1)
+
+	s := NewService(nil, nil, nil)
+
+	defer func() {
+		require.Nil(t, recover())
+	}()
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/ping", func(w http.ResponseWriter, r *http.Request) {
+		time.Sleep(pingTimeout + 1*time.Second)
+	})
+
+	ln, err := net.ListenTCP("tcp", &net.TCPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 0})
+	require.NoError(t, err)
+
+	go func() {
+		require.NoError(t, http.Serve(ln, mux))
+	}()
+
+	s.getTunnelDetails(endpointID)
+	s.tunnelDetailsMap[endpointID].Port = ln.Addr().(*net.TCPAddr).Port
+
+	require.Error(t, s.pingAgent(endpointID))
+}