From 0ce3a12e87c639d32d730405c30a5225dddeaea1 Mon Sep 17 00:00:00 2001
From: Roman Khimov <roman@nspcc.ru>
Date: Thu, 21 May 2020 14:27:19 +0300
Subject: [PATCH] core: check for key length in CheckWitness, fix #968

Only one type of keys is allowed here.
---
 pkg/core/interop_system.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkg/core/interop_system.go b/pkg/core/interop_system.go
index 9f8b4fc14..bfa669bda 100644
--- a/pkg/core/interop_system.go
+++ b/pkg/core/interop_system.go
@@ -322,6 +322,10 @@ func (ic *interopContext) runtimeCheckWitness(v *vm.VM) error {
 	hashOrKey := v.Estack().Pop().Bytes()
 	hash, err := util.Uint160DecodeBytesBE(hashOrKey)
 	if err != nil {
+		// We only accept compressed keys here as per C# implementation.
+		if len(hashOrKey) != 33 {
+			return errors.New("bad parameter length")
+		}
 		key := &keys.PublicKey{}
 		err = key.DecodeBytes(hashOrKey)
 		if err != nil {