From 9ade45d81b804da7b1c722e22d0c9f422f5d70a0 Mon Sep 17 00:00:00 2001
From: William Banfield <4561443+williambanfield@users.noreply.github.com>
Date: Wed, 22 Dec 2021 11:09:57 -0500
Subject: [PATCH] consensus: check that proposal is non-nil before voting
 (#7480)

---
 internal/consensus/state.go | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/internal/consensus/state.go b/internal/consensus/state.go
index 1409a6f51..f0988318a 100644
--- a/internal/consensus/state.go
+++ b/internal/consensus/state.go
@@ -1321,6 +1321,12 @@ func (cs *State) defaultDoPrevote(height int64, round int32) {
 		return
 	}
 
+	if cs.Proposal == nil || cs.ProposalBlock == nil {
+		logger.Debug("prevote step; did not receive proposal, prevoting nil")
+		cs.signAddVote(tmproto.PrevoteType, nil, types.PartSetHeader{})
+		return
+	}
+
 	if !cs.Proposal.Timestamp.Equal(cs.ProposalBlock.Header.Time) {
 		logger.Debug("proposal timestamp not equal, prevoting nil")
 		cs.signAddVote(tmproto.PrevoteType, nil, types.PartSetHeader{})
@@ -1489,6 +1495,13 @@ func (cs *State) enterPrecommit(height int64, round int32) {
 	}
 	// At this point, +2/3 prevoted for a particular block.
 
+	// If we never received a proposal for this block, we must precommit nil
+	if cs.Proposal == nil || cs.ProposalBlock == nil {
+		logger.Debug("precommit step; did not receive proposal, precommitting nil")
+		cs.signAddVote(tmproto.PrecommitType, nil, types.PartSetHeader{})
+		return
+	}
+
 	// If the proposal time does not match the block time, precommit nil.
 	if !cs.Proposal.Timestamp.Equal(cs.ProposalBlock.Header.Time) {
 		logger.Debug("proposal timestamp not equal, precommitting nil")