[client] Ignore candidates that are part of the the wireguard subnet (#3472)

client/iface/bind/ice_bind.go

@@ -13,6 +13,8 @@ import (
 	"golang.org/x/net/ipv4"
 	"golang.org/x/net/ipv6"
 	wgConn "golang.zx2c4.com/wireguard/conn"
+
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 )
 
 type RecvMessage struct {
@@ -51,9 +53,10 @@ type ICEBind struct {
 
 	muUDPMux sync.Mutex
 	udpMux   *UniversalUDPMuxDefault
+	address  wgaddr.Address
 }
 
-func NewICEBind(transportNet transport.Net, filterFn FilterFn) *ICEBind {
+func NewICEBind(transportNet transport.Net, filterFn FilterFn, address wgaddr.Address) *ICEBind {
 	b, _ := wgConn.NewStdNetBind().(*wgConn.StdNetBind)
 	ib := &ICEBind{
 		StdNetBind:   b,
@@ -63,6 +66,7 @@ func NewICEBind(transportNet transport.Net, filterFn FilterFn) *ICEBind {
 		endpoints:    make(map[netip.Addr]net.Conn),
 		closedChan:   make(chan struct{}),
 		closed:       true,
+		address:      address,
 	}
 
 	rc := receiverCreator{
@@ -142,9 +146,10 @@ func (s *ICEBind) createIPv4ReceiverFn(pc *ipv4.PacketConn, conn *net.UDPConn, r
 
 	s.udpMux = NewUniversalUDPMuxDefault(
 		UniversalUDPMuxParams{
-			UDPConn:  conn,
-			Net:      s.transportNet,
-			FilterFn: s.filterFn,
+			UDPConn:   conn,
+			Net:       s.transportNet,
+			FilterFn:  s.filterFn,
+			WGAddress: s.address,
 		},
 	)
 	return func(bufs [][]byte, sizes []int, eps []wgConn.Endpoint) (n int, err error) {

client/iface/bind/udp_mux_universal.go

@@ -17,6 +17,8 @@ import (
 	"github.com/pion/logging"
 	"github.com/pion/stun/v2"
 	"github.com/pion/transport/v3"
+
+	"github.com/netbirdio/netbird/client/iface/wgaddr"
 )
 
 // FilterFn is a function that filters out candidates based on the address.
@@ -41,6 +43,7 @@ type UniversalUDPMuxParams struct {
 	XORMappedAddrCacheTTL time.Duration
 	Net                   transport.Net
 	FilterFn              FilterFn
+	WGAddress             wgaddr.Address
 }
 
 // NewUniversalUDPMuxDefault creates an implementation of UniversalUDPMux embedding UDPMux
@@ -64,6 +67,7 @@ func NewUniversalUDPMuxDefault(params UniversalUDPMuxParams) *UniversalUDPMuxDef
 		mux:        m,
 		logger:     params.Logger,
 		filterFn:   params.FilterFn,
+		address:    params.WGAddress,
 	}
 
 	// embed UDPMux
@@ -118,6 +122,7 @@ type udpConn struct {
 	filterFn FilterFn
 	// TODO: reset cache on route changes
 	addrCache sync.Map
+	address   wgaddr.Address
 }
 
 func (u *udpConn) WriteTo(b []byte, addr net.Addr) (int, error) {
@@ -159,6 +164,11 @@ func (u *udpConn) performFilterCheck(addr net.Addr) error {
 		return nil
 	}
 
+	if u.address.Network.Contains(a.AsSlice()) {
+		log.Warnf("Address %s is part of the NetBird network %s, refusing to write", addr, u.address)
+		return fmt.Errorf("address %s is part of the NetBird network %s, refusing to write", addr, u.address)
+	}
+
 	if isRouted, prefix, err := u.filterFn(a); err != nil {
 		log.Errorf("Failed to check if address %s is routed: %v", addr, err)
 	} else {