From 215f402231b78f3d1edc430a171802ae0a33df86 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Sun, 20 Jul 2025 15:18:51 +0200
Subject: [PATCH] core, params: add limit for max blobs in blob transaction

---
 core/block_validator.go   | 5 +++++
 core/error.go             | 3 +++
 core/state_transition.go  | 6 +++++-
 params/protocol_params.go | 1 +
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/core/block_validator.go b/core/block_validator.go
index 008444fbbc..3a0635b517 100644
--- a/core/block_validator.go
+++ b/core/block_validator.go
@@ -86,8 +86,13 @@ func (v *BlockValidator) ValidateBody(block *types.Block) error {
 	}
 
 	// Blob transactions may be present after the Cancun fork.
+	isOsaka := v.config.IsOsaka(block.Number(), block.Time())
 	var blobs int
 	for i, tx := range block.Transactions() {
+		if isOsaka && len(tx.BlobHashes()) > params.BlobTxMaxBlobs {
+			return ErrTooManyBlobs
+		}
+
 		// Count the number of blobs to validate against the header's blobGasUsed
 		blobs += len(tx.BlobHashes())
 
diff --git a/core/error.go b/core/error.go
index b9e894bd9b..635d802863 100644
--- a/core/error.go
+++ b/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")
 
diff --git a/core/state_transition.go b/core/state_transition.go
index de4558253b..681c300696 100644
--- a/core/state_transition.go
+++ b/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()
diff --git a/params/protocol_params.go b/params/protocol_params.go
index 3b48709a88..2ec3a5c249 100644
--- a/params/protocol_params.go
+++ b/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.