From ae0636254c5f6232d78b7d9a9908eee434639406 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Thu, 15 May 2025 16:48:14 +0200 Subject: [PATCH] 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. cherry picked from commit WireGuard/wireguard-go@842888ac5c93ccc5ee6344eceaadf783fcf1e243 Updates tailscale/corp#28879 Signed-off-by: Jason A. Donenfeld --- device/noise-protocol.go | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/device/noise-protocol.go b/device/noise-protocol.go index 2e7e9ae..1e99f68 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)