Store group sigs in the real header, not in a copy

(*Block) Header() returns a (shallow) copy of the header, where we were
storing group signatures and signer bitmaps.  This had no effect, and
the on-chain block was still missing these signatures.

consensus/consensus_leader.go

@@ -308,10 +308,12 @@ func (consensus *Consensus) processCommitMessage(message *msg_pb.Message) {
 		}
 
 		// Sign the block
-		copy(blockObj.Header().PrepareSignature[:], consensus.aggregatedPrepareSig.Serialize()[:])
+		blockObj.SetPrepareSig(
-		copy(blockObj.Header().PrepareBitmap[:], consensus.prepareBitmap.Bitmap)
+			consensus.aggregatedPrepareSig.Serialize(),
-		copy(blockObj.Header().CommitSignature[:], consensus.aggregatedCommitSig.Serialize()[:])
+			consensus.prepareBitmap.Bitmap)
-		copy(blockObj.Header().CommitBitmap[:], consensus.commitBitmap.Bitmap)
+		blockObj.SetCommitSig(
+			consensus.aggregatedCommitSig.Serialize(),
+			consensus.commitBitmap.Bitmap)
 
 		consensus.state = targetState
 

consensus/consensus_validator.go

@@ -282,10 +282,12 @@ func (consensus *Consensus) processCommittedMessage(message *msg_pb.Message) {
 			}
 
 			// Put the signatures into the block
-			copy(blockObj.Header().PrepareSignature[:], consensus.aggregatedPrepareSig.Serialize()[:])
+			blockObj.SetPrepareSig(
-			copy(blockObj.Header().PrepareBitmap[:], consensus.prepareBitmap.Bitmap)
+				consensus.aggregatedPrepareSig.Serialize(),
-			copy(blockObj.Header().CommitSignature[:], consensus.aggregatedCommitSig.Serialize()[:])
+				consensus.prepareBitmap.Bitmap)
-			copy(blockObj.Header().CommitBitmap[:], consensus.commitBitmap.Bitmap)
+			blockObj.SetCommitSig(
+				consensus.aggregatedCommitSig.Serialize(),
+				consensus.commitBitmap.Bitmap)
 			utils.GetLogInstance().Info("Adding block to chain", "numTx", len(blockObj.Transactions()))
 			consensus.OnConsensusDone(&blockObj)
 			consensus.ResetState()

core/types/block.go

@@ -30,6 +30,8 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/rlp"
 	"golang.org/x/crypto/sha3"
+
+	"github.com/harmony-one/harmony/internal/utils"
 )
 
 // Constants for block.
@@ -159,6 +161,28 @@ type Block struct {
 	ReceivedFrom interface{}
 }
 
+// SetPrepareSig sets the block's prepare group signature.
+func (b *Block) SetPrepareSig(sig []byte, signers []byte) {
+	if len(sig) != len(b.header.PrepareSignature) {
+		utils.GetLogInstance().Warn("SetPrepareSig: sig size mismatch",
+			"srcLen", len(sig),
+			"dstLen", len(b.header.PrepareSignature))
+	}
+	copy(b.header.PrepareSignature[:], sig[:])
+	b.header.PrepareBitmap = append(signers[:0:0], signers...)
+}
+
+// SetCommitSig sets the block's commit group signature.
+func (b *Block) SetCommitSig(sig []byte, signers []byte) {
+	if len(sig) != len(b.header.CommitSignature) {
+		utils.GetLogInstance().Warn("SetCommitSig: sig size mismatch",
+			"srcLen", len(sig),
+			"dstLen", len(b.header.CommitSignature))
+	}
+	copy(b.header.CommitSignature[:], sig[:])
+	b.header.CommitBitmap = append(signers[:0:0], signers...)
+}
+
 // DeprecatedTd is an old relic for extracting the TD of a block. It is in the
 // code solely to facilitate upgrading the database from the old format to the
 // new, after which it should be deleted. Do not use!