Fix: drop UDP packet which mismatched destination for VMess (#2410)

Co-authored-by: SUN Sizhe <sunsizhe@cmi.chinamobile.com>
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Sizhe Sun 2022-11-26 11:27:24 +08:00 committed by GitHub
parent ed988dcdc5
commit 90b40a8e5a
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1 changed files with 9 additions and 0 deletions

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@ -20,6 +20,8 @@ import (
"golang.org/x/net/http2"
)
var ErrUDPRemoteAddrMismatch = errors.New("udp packet dropped due to mismatched remote address")
type Vmess struct {
*Base
client *vmess.Client
@ -358,7 +360,14 @@ type vmessPacketConn struct {
rAddr net.Addr
}
// WriteTo implments C.PacketConn.WriteTo
// Since VMess doesn't support full cone NAT by design, we verify if addr matches uc.rAddr, and drop the packet if not.
func (uc *vmessPacketConn) WriteTo(b []byte, addr net.Addr) (int, error) {
allowedAddr := uc.rAddr.(*net.UDPAddr)
destAddr := addr.(*net.UDPAddr)
if !(allowedAddr.IP.Equal(destAddr.IP) && allowedAddr.Port == destAddr.Port) {
return 0, ErrUDPRemoteAddrMismatch
}
return uc.Conn.Write(b)
}