Merge pull request #421 from bane-labs/ensure-decrypted-hash

Author: roman-khimov

antimev/envelope.go

@@ -37,7 +37,7 @@ var (
 	minEncryptedDataSize = EncryptedDataPrefixLen + EncryptedDataRoundLen + EncryptedDataHashLen + tpke.CipherTextSize + 105 + (aes.BlockSize - 105%aes.BlockSize)
 )
 
-// isEnvelope checks whether a transaction is an Envelope transaction. The criteria
+// IsEnvelope checks whether a transaction is an Envelope transaction. The criteria
 // include receiver's address, data prefix and data length check.
 func IsEnvelope(tx *types.Transaction) bool {
 	if tx.To() == nil || *(tx.To()) != systemcontracts.GovernanceRewardProxyHash {
@@ -51,3 +51,10 @@ func IsEnvelope(tx *types.Transaction) bool {
 
 	return true
 }
+
+// GetEncryptedHash returns the hash of inner encrypted transaction specified in an
+// unencrypted part of Envelope data. Passing non-Envelope as an argument is a no-op.
+func GetEncryptedHash(envelope *types.Transaction) common.Hash {
+	hashOffset := EncryptedDataPrefixLen + EncryptedDataRoundLen
+	return common.Hash(envelope.Data()[hashOffset : hashOffset+EncryptedDataHashLen])
+}

consensus/dbft/dbft.go

@@ -1237,11 +1237,14 @@ func (c *DBFT) validateDecryptedTx(head *types.Header, decryptedTx *types.Transa
 	if decryptedTx.Nonce() != envelope.Nonce() {
 		return fmt.Errorf("decryptedTx nonce mismatch: decryptedNonce %v, envelopeNonce %v", decryptedTx.Nonce(), envelope.Nonce())
 	}
+
 	// Ensure the gasprice is high enough to replace the envelope transaction
 	baseFee := head.BaseFee
 	if decryptedTx.EffectiveGasTipCmp(envelope, baseFee) < 0 {
 		return fmt.Errorf("decryptedTx underpriced: EffectiveGasTip needed %v, EffectiveGasTip permitted %v", envelope.EffectiveGasTipValue(baseFee), decryptedTx.EffectiveGasTipValue(baseFee))
 	}
+
+	// Ensure envelope sender matches decrypted sender.
 	envelopeFrom, err := types.Sender(c.signerConfig, envelope)
 	if err != nil {
 		return fmt.Errorf("%w: failed to retrieve envelope sender: %w", txpool.ErrInvalidSender, err)
@@ -1253,6 +1256,13 @@ func (c *DBFT) validateDecryptedTx(head *types.Header, decryptedTx *types.Transa
 	if envelopeFrom != decryptedFrom {
 		return fmt.Errorf("decryptedTx from mismatch: decryptedFrom %v, envelopeFrom %v", decryptedFrom, envelopeFrom)
 	}
+
+	// Ensure decrypted hash matches the one specified in an unencrypted part of Envelope data.
+	expectedH := antimev.GetEncryptedHash(envelope)
+	if decryptedTx.Hash().Cmp(expectedH) != 0 {
+		return fmt.Errorf("decryptedTx hash mismatch: expected %s, got %s", expectedH, decryptedTx.Hash())
+	}
+
 	return nil
 }
 

internal/ethapi/api.go

@@ -1893,8 +1893,7 @@ func SubmitTransaction(ctx context.Context, b Backend, tx *types.Transaction) (c
 
 	// If the transaction is an antimev envelope, then return the declared transaction hash instead of its own.
 	if antimev.IsEnvelope(tx) {
-		hashOffSet := antimev.EncryptedDataPrefixLen + antimev.EncryptedDataRoundLen
-		return common.Hash(tx.Data()[hashOffSet : hashOffSet+antimev.EncryptedDataHashLen]), nil
+		return antimev.GetEncryptedHash(tx), nil
 	} else {
 		return tx.Hash(), nil
 	}