From e3b9e2543bb98cec74a5fe2436c4fea4c6b7276f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=A3=8E=E6=89=87=E6=BB=91=E7=BF=94=E7=BF=BC?=
 <Fangliding.fshxy@outlook.com>
Date: Wed, 7 May 2025 14:14:30 +0000
Subject: [PATCH] Add packet length valid check

---
 common/protocol/quic/sniff.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/common/protocol/quic/sniff.go b/common/protocol/quic/sniff.go
index 73b9bf97..0f07f6ff 100644
--- a/common/protocol/quic/sniff.go
+++ b/common/protocol/quic/sniff.go
@@ -4,8 +4,8 @@ import (
 	"crypto"
 	"crypto/aes"
 	"crypto/tls"
-	"fmt"
 	"encoding/binary"
+	"fmt"
 	"io"
 
 	"github.com/quic-go/quic-go/quicvarint"
@@ -169,6 +169,10 @@ func SniffQUIC(b []byte) (*SniffHeader, error) {
 			return nil, err
 		}
 
+		// very stange packet length, maybe a fake QUIC header
+		if packetNumberLength > int(packetLen) {
+			return nil, errNotQuic
+		}
 		extHdrLen := hdrLen + packetNumberLength
 		data := b[extHdrLen : int(packetLen)+hdrLen]
 		decrypted, err := cipher.Open(b[extHdrLen:extHdrLen], nonce, data, b[:extHdrLen])