core, params: add limit for max blobs in blob transaction (#32246)

[EIP-7594](https://eips.ethereum.org/EIPS/eip-7594) defines a limit of
max 6 blobs per transaction. We need to enforce this limit during block
processing.

> Additionally, a limit of 6 blobs per transaction is introduced.
Clients MUST enforce this limit when validating blob transactions at
submission time, when received from the network, and during block
production and processing.

Author: fjl

core/error.go

@@ -118,6 +118,9 @@ var (
 	// ErrMissingBlobHashes is returned if a blob transaction has no blob hashes.
 	ErrMissingBlobHashes = errors.New("blob transaction missing blob hashes")
 
+	// ErrTooManyBlobs is returned if a blob transaction exceeds the maximum number of blobs.
+	ErrTooManyBlobs = errors.New("blob transaction has too many blobs")
+
 	// ErrBlobTxCreate is returned if a blob transaction has no explicit to field.
 	ErrBlobTxCreate = errors.New("blob transaction of type create")
 

core/state_transition.go

@@ -354,6 +354,7 @@ func (st *stateTransition) preCheck() error {
 		}
 	}
 	// Check the blob version validity
+	isOsaka := st.evm.ChainConfig().IsOsaka(st.evm.Context.BlockNumber, st.evm.Context.Time)
 	if msg.BlobHashes != nil {
 		// The to field of a blob tx type is mandatory, and a `BlobTx` transaction internally
 		// has it as a non-nillable value, so any msg derived from blob transaction has it non-nil.
@@ -364,6 +365,9 @@ func (st *stateTransition) preCheck() error {
 		if len(msg.BlobHashes) == 0 {
 			return ErrMissingBlobHashes
 		}
+		if isOsaka && len(msg.BlobHashes) > params.BlobTxMaxBlobs {
+			return ErrTooManyBlobs
+		}
 		for i, hash := range msg.BlobHashes {
 			if !kzg4844.IsValidVersionedHash(hash[:]) {
 				return fmt.Errorf("blob %d has invalid hash version", i)
@@ -395,7 +399,7 @@ func (st *stateTransition) preCheck() error {
 		}
 	}
 	// Verify tx gas limit does not exceed EIP-7825 cap.
-	if st.evm.ChainConfig().IsOsaka(st.evm.Context.BlockNumber, st.evm.Context.Time) && msg.GasLimit > params.MaxTxGas {
+	if isOsaka && msg.GasLimit > params.MaxTxGas {
 		return fmt.Errorf("%w (cap: %d, tx: %d)", ErrGasLimitTooHigh, params.MaxTxGas, msg.GasLimit)
 	}
 	return st.buyGas()

core/txpool/blobpool/blobpool.go

@@ -65,7 +65,7 @@ const (
 	// carry. We choose a smaller limit than the protocol-permitted MaxBlobsPerBlock
 	// in order to ensure network and txpool stability.
 	// Note: if you increase this, validation will fail on txMaxSize.
-	maxBlobsPerTx = 7
+	maxBlobsPerTx = params.BlobTxMaxBlobs
 
 	// maxTxsPerAccount is the maximum number of blob transactions admitted from
 	// a single account. The limit is enforced to minimize the DoS potential of

core/txpool/blobpool/blobpool_test.go

@@ -1191,8 +1191,8 @@ func TestBlobCountLimit(t *testing.T) {
 
 	// Attempt to add transactions.
 	var (
-		tx1 = makeMultiBlobTx(0, 1, 1000, 100, 7, key1)
-		tx2 = makeMultiBlobTx(0, 1, 800, 70, 8, key2)
+		tx1 = makeMultiBlobTx(0, 1, 1000, 100, 6, key1)
+		tx2 = makeMultiBlobTx(0, 1, 800, 70, 7, key2)
 	)
 	errs := pool.Add([]*types.Transaction{tx1, tx2}, true)
 

params/protocol_params.go

@@ -177,6 +177,7 @@ const (
 	BlobTxBlobGasPerBlob               = 1 << 17 // Gas consumption of a single data blob (== blob byte size)
 	BlobTxMinBlobGasprice              = 1       // Minimum gas price for data blobs
 	BlobTxPointEvaluationPrecompileGas = 50000   // Gas price for the point evaluation precompile.
+	BlobTxMaxBlobs                     = 6
 	BlobBaseCost                       = 1 << 13 // Base execution gas cost for a blob.
 
 	HistoryServeWindow = 8192 // Number of blocks to serve historical block hashes for, EIP-2935.