From c3f4e1ba2e2d7fffd4d8786d76f2ac1948f17733 Mon Sep 17 00:00:00 2001
From: Kaming Chan <hi@terrychan.me>
Date: Fri, 13 May 2022 11:21:39 +0800
Subject: [PATCH] fix: add length check for ssr auth_aes128_sha1 (#2129)

---
 transport/ssr/protocol/auth_aes128_sha1.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/transport/ssr/protocol/auth_aes128_sha1.go b/transport/ssr/protocol/auth_aes128_sha1.go
index d31fb9bf..7b4da962 100644
--- a/transport/ssr/protocol/auth_aes128_sha1.go
+++ b/transport/ssr/protocol/auth_aes128_sha1.go
@@ -154,6 +154,9 @@ func (a *authAES128) Encode(buf *bytes.Buffer, b []byte) error {
 }
 
 func (a *authAES128) DecodePacket(b []byte) ([]byte, error) {
+	if len(b) < 4 {
+		return nil, errAuthAES128LengthError
+	}
 	if !bytes.Equal(a.hmac(a.Key, b[:len(b)-4])[:4], b[len(b)-4:]) {
 		return nil, errAuthAES128ChksumError
 	}