Fix panic unmarshalling hello verify request

Sam Lancia · daenney · commit a50d26c5e4ee · 2023-02-05T15:47:16.000+01:00
This could cause us to panic when unmarshalling a Hello Verify request
message.
diff --git a/pkg/protocol/handshake/message_hello_verify_request.go b/pkg/protocol/handshake/message_hello_verify_request.go
@@ -51,8 +51,8 @@ func (m *MessageHelloVerifyRequest) Unmarshal(data []byte) error {
 	}
 	m.Version.Major = data[0]
 	m.Version.Minor = data[1]
-	cookieLength := data[2]
-	if len(data) < (int(cookieLength) + 3) {
+	cookieLength := int(data[2])
+	if len(data) < cookieLength+3 {
 		return errBufferTooSmall
 	}
 	m.Cookie = make([]byte, cookieLength)

Original file line number	Diff line number	Diff line change
`@@ -51,8 +51,8 @@ func (m *MessageHelloVerifyRequest) Unmarshal(data []byte) error {`
`51`	`51`	`}`
`52`	`52`	`m.Version.Major = data[0]`
`53`	`53`	`m.Version.Minor = data[1]`
`54`		`- cookieLength := data[2]`
`55`		`- if len(data) < (int(cookieLength) + 3) {`
	`54`	`+ cookieLength := int(data[2])`
	`55`	`+ if len(data) < cookieLength+3 {`
`56`	`56`	`return errBufferTooSmall`
`57`	`57`	`}`
`58`	`58`	`m.Cookie = make([]byte, cookieLength)`