Additional header validations (#1508)

Additional header validations
Co-authored-by: Stefan Negovanović <93934272+Stefan-Ethernal@users.noreply.github.com>

consensus/polybft/fsm.go

@@ -632,6 +632,10 @@ func (f *fsm) verifyDistributeRewardsTx(distributeRewardsTx *types.Transaction)
 }
 
 func validateHeaderFields(parent *types.Header, header *types.Header) error {
+	// header extra data must be higher or equal to ExtraVanity = 32 in order to be compliant with Ethereum blocks
+	if len(header.ExtraData) < ExtraVanity {
+		return fmt.Errorf("extra-data shorter than %d bytes (%d)", ExtraVanity, len(header.ExtraData))
+	}
 	// verify parent hash
 	if parent.Hash != header.ParentHash {
 		return fmt.Errorf("incorrect header parent hash (parent=%s, header parent=%s)", parent.Hash, header.ParentHash)
@@ -640,6 +644,14 @@ func validateHeaderFields(parent *types.Header, header *types.Header) error {
 	if header.Number != parent.Number+1 {
 		return fmt.Errorf("invalid number")
 	}
+	// verify header nonce is zero
+	if header.Nonce != types.ZeroNonce {
+		return fmt.Errorf("invalid nonce")
+	}
+	// verify that the gasUsed is <= gasLimit
+	if header.GasUsed > header.GasLimit {
+		return fmt.Errorf("invalid gas limit: have %v, max %v", header.GasUsed, header.GasLimit)
+	}
 	// verify time has passed
 	if header.Timestamp <= parent.Timestamp {
 		return fmt.Errorf("timestamp older than parent")

consensus/polybft/fsm_test.go

@@ -27,9 +27,14 @@ import (
 func TestFSM_ValidateHeader(t *testing.T) {
 	t.Parallel()
 
+	extra := createTestExtra(validator.AccountSet{}, validator.AccountSet{}, 0, 0, 0)
 	parent := &types.Header{Number: 0, Hash: types.BytesToHash([]byte{1, 2, 3})}
 	header := &types.Header{Number: 0}
 
+	// parent extra data
+	require.ErrorContains(t, validateHeaderFields(parent, header), "extra-data shorter than")
+	header.ExtraData = extra
+
 	// parent hash
 	require.ErrorContains(t, validateHeaderFields(parent, header), "incorrect header parent hash")
 	header.ParentHash = parent.Hash
@@ -42,6 +47,18 @@ func TestFSM_ValidateHeader(t *testing.T) {
 	require.ErrorContains(t, validateHeaderFields(parent, header), "timestamp older than parent")
 	header.Timestamp = 10
 
+	// failed nonce
+	header.SetNonce(1)
+	require.ErrorContains(t, validateHeaderFields(parent, header), "invalid nonce")
+	header.SetNonce(0)
+
+	// failed gas
+	header.GasLimit = 10
+	header.GasUsed = 11
+	require.ErrorContains(t, validateHeaderFields(parent, header), "invalid gas limit")
+	header.GasLimit = 10
+	header.GasUsed = 10
+
 	// mix digest
 	require.ErrorContains(t, validateHeaderFields(parent, header), "mix digest is not correct")
 	header.MixHash = PolyBFTMixDigest

types/types.go

@@ -24,6 +24,9 @@ var (
 	// ZeroHash is the default zero hash
 	ZeroHash = Hash{}
 
+	// ZeroNonce is the default empty nonce
+	ZeroNonce = Nonce{}
+
 	// EmptyRootHash is the root when there are no transactions
 	EmptyRootHash = StringToHash("0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421")