From 83dc18e7f10d60428a1da15de2842e284059ef67 Mon Sep 17 00:00:00 2001
From: Leo Chen <leo@harmony.one>
Date: Sat, 23 May 2020 23:50:22 -0700
Subject: [PATCH] fix nil pointer crash

Signed-off-by: Leo Chen <leo@harmony.one>
---
 internal/chain/engine.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/internal/chain/engine.go b/internal/chain/engine.go
index 60bb4141b..1b3eb1ade 100644
--- a/internal/chain/engine.go
+++ b/internal/chain/engine.go
@@ -172,6 +172,9 @@ func (e *engineImpl) VerifySeal(chain engine.ChainReader, header *block.Header)
 	if chain.CurrentHeader().Number().Uint64() <= uint64(1) {
 		return nil
 	}
+	if header == nil {
+		return errors.New("[VerifySeal] nil block header")
+	}
 	publicKeys, err := ReadPublicKeysFromLastBlock(chain, header)
 
 	if err != nil {