finality: add more check to ensure reuslt of assembleVoteAttestation (#1791)

Author: NathanBSC

consensus/parlia/parlia.go

@@ -882,6 +882,11 @@ func (p *Parlia) assembleVoteAttestation(chain consensus.ChainHeaderReader, head
 			attestation.VoteAddressSet |= 1 << (valInfo.Index - 1) //Index is offset by 1
 		}
 	}
+	validatorsBitSet := bitset.From([]uint64{uint64(attestation.VoteAddressSet)})
+	if validatorsBitSet.Count() < uint(len(signatures)) {
+		log.Warn(fmt.Sprintf("assembleVoteAttestation, check VoteAddress Set failed, expected:%d, real:%d", len(signatures), validatorsBitSet.Count()))
+		return fmt.Errorf("invalid attestation, check VoteAddress Set failed")
+	}
 
 	// Append attestation to header extra field.
 	buf := new(bytes.Buffer)
@@ -1758,7 +1763,6 @@ func (p *Parlia) GetFinalizedHeader(chain consensus.ChainHeaderReader, header *t
 		return nil
 	}
 
-	// snap.Attestation is nil after plato upgrade, only can happen in local testnet
 	if snap.Attestation == nil {
 		return chain.GetHeaderByNumber(0) // keep consistent with GetJustifiedNumberAndHash
 	}