From e0ef563edf0bae94c253f9f363173269fac354b0 Mon Sep 17 00:00:00 2001
From: Manav Darji <manavdarji.india@gmail.com>
Date: Fri, 6 Jan 2023 22:05:44 +0530
Subject: [PATCH] consensus/bor: handle unauthorized signer in
 consensus.Prepare

---
 consensus/bor/bor.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/consensus/bor/bor.go b/consensus/bor/bor.go
index b6d643eeba..4f367430ec 100644
--- a/consensus/bor/bor.go
+++ b/consensus/bor/bor.go
@@ -676,6 +676,13 @@ func (c *Bor) Prepare(chain consensus.ChainHeaderReader, header *types.Header) e
 
 	currentSigner := *c.authorizedSigner.Load()
 
+	// Bail out early if we're unauthorized to sign a block. This check also takes
+	// place before block is signed in `Seal`.
+	if !snap.ValidatorSet.HasAddress(currentSigner.signer) {
+		// Check the UnauthorizedSignerError.Error() msg to see why we pass number-1
+		return &UnauthorizedSignerError{number - 1, currentSigner.signer.Bytes()}
+	}
+
 	// Set the correct difficulty
 	header.Difficulty = new(big.Int).SetUint64(Difficulty(snap.ValidatorSet, currentSigner.signer))