From: Jason A. Donenfeld <Jason@zx2c4.com>
Date: Thu, 15 May 2025 14:48:14 +0000 (+0200)
Subject: device: make unmarshall length checks exact
X-Git-Tag: 0.0.20250515~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=842888ac5c93ccc5ee6344eceaadf783fcf1e243;p=thirdparty%2Fwireguard-go.git

device: make unmarshall length checks exact

This is already enforced in receive.go, but if these unmarshallers are
to have error return values anyway, make them as explicit as possible.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---

diff --git a/device/noise-protocol.go b/device/noise-protocol.go
index 12368ec..5f713ee 100644
--- a/device/noise-protocol.go
+++ b/device/noise-protocol.go
@@ -116,11 +116,11 @@ type MessageCookieReply struct {
 	Cookie   [blake2s.Size128 + poly1305.TagSize]byte
 }
 
-var errMessageTooShort = errors.New("message too short")
+var errMessageLengthMismatch = errors.New("message length mismatch")
 
 func (msg *MessageInitiation) unmarshal(b []byte) error {
-	if len(b) < MessageInitiationSize {
-		return errMessageTooShort
+	if len(b) != MessageInitiationSize {
+		return errMessageLengthMismatch
 	}
 
 	msg.Type = binary.LittleEndian.Uint32(b)
@@ -135,8 +135,8 @@ func (msg *MessageInitiation) unmarshal(b []byte) error {
 }
 
 func (msg *MessageResponse) unmarshal(b []byte) error {
-	if len(b) < MessageResponseSize {
-		return errMessageTooShort
+	if len(b) != MessageResponseSize {
+		return errMessageLengthMismatch
 	}
 
 	msg.Type = binary.LittleEndian.Uint32(b)
@@ -151,8 +151,8 @@ func (msg *MessageResponse) unmarshal(b []byte) error {
 }
 
 func (msg *MessageCookieReply) unmarshal(b []byte) error {
-	if len(b) < MessageCookieReplySize {
-		return errMessageTooShort
+	if len(b) != MessageCookieReplySize {
+		return errMessageLengthMismatch
 	}
 
 	msg.Type = binary.LittleEndian.Uint32(b)