QUIC sniffer: Don't accept ClientHello with gaps in CRYPTO data (#7292)

https://github.com/XTLS/Xray-core/pull/7292#pullrequestreview-5712194488

---------

Co-authored-by: 风扇滑翔翼 <Fangliding.fshxy@outlook.com>

common/protocol/tls/sniff.go

@@ -101,6 +101,10 @@ func ReadClientHello(data []byte, h *SniffHeader) error {
 					return errNotClientHello
 				}
 				if nameType == 0 {
+					// RFC 6066 requires a non-empty HostName.
+					if nameLen == 0 {
+						return errNotClientHello
+					}
 					// QUIC separated across packets
 					// May cause the serverName to be incomplete
 					b := byte(0)