internal/ethapi: add support for blobs in eth_fillTransaction (#28839)

This change adds support for blob-transaction in certain API-endpoints, e.g. eth_fillTransaction. A follow-up PR will add support for signing such transactions.

core/types/transaction_marshalling.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 	"github.com/holiman/uint256"
 )
 
@@ -47,6 +48,11 @@ type txJSON struct {
 	S                    *hexutil.Big    `json:"s"`
 	YParity              *hexutil.Uint64 `json:"yParity,omitempty"`
 
+	// Blob transaction sidecar encoding:
+	Blobs       []kzg4844.Blob       `json:"blobs,omitempty"`
+	Commitments []kzg4844.Commitment `json:"commitments,omitempty"`
+	Proofs      []kzg4844.Proof      `json:"proofs,omitempty"`
+
 	// Only used for encoding:
 	Hash common.Hash `json:"hash"`
 }
@@ -142,6 +148,11 @@ func (tx *Transaction) MarshalJSON() ([]byte, error) {
 		enc.S = (*hexutil.Big)(itx.S.ToBig())
 		yparity := itx.V.Uint64()
 		enc.YParity = (*hexutil.Uint64)(&yparity)
+		if sidecar := itx.Sidecar; sidecar != nil {
+			enc.Blobs = itx.Sidecar.Blobs
+			enc.Commitments = itx.Sidecar.Commitments
+			enc.Proofs = itx.Sidecar.Proofs
+		}
 	}
 	return json.Marshal(&enc)
 }

crypto/kzg4844/kzg4844.go

@@ -21,21 +21,60 @@ import (
 	"embed"
 	"errors"
 	"hash"
+	"reflect"
 	"sync/atomic"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
 )
 
 //go:embed trusted_setup.json
 var content embed.FS
 
+var (
+	blobT       = reflect.TypeOf(Blob{})
+	commitmentT = reflect.TypeOf(Commitment{})
+	proofT      = reflect.TypeOf(Proof{})
+)
+
 // Blob represents a 4844 data blob.
 type Blob [131072]byte
 
+// UnmarshalJSON parses a blob in hex syntax.
+func (b *Blob) UnmarshalJSON(input []byte) error {
+	return hexutil.UnmarshalFixedJSON(blobT, input, b[:])
+}
+
+// MarshalText returns the hex representation of b.
+func (b Blob) MarshalText() ([]byte, error) {
+	return hexutil.Bytes(b[:]).MarshalText()
+}
+
 // Commitment is a serialized commitment to a polynomial.
 type Commitment [48]byte
 
+// UnmarshalJSON parses a commitment in hex syntax.
+func (c *Commitment) UnmarshalJSON(input []byte) error {
+	return hexutil.UnmarshalFixedJSON(commitmentT, input, c[:])
+}
+
+// MarshalText returns the hex representation of c.
+func (c Commitment) MarshalText() ([]byte, error) {
+	return hexutil.Bytes(c[:]).MarshalText()
+}
+
 // Proof is a serialized commitment to the quotient polynomial.
 type Proof [48]byte
 
+// UnmarshalJSON parses a proof in hex syntax.
+func (p *Proof) UnmarshalJSON(input []byte) error {
+	return hexutil.UnmarshalFixedJSON(proofT, input, p[:])
+}
+
+// MarshalText returns the hex representation of p.
+func (p Proof) MarshalText() ([]byte, error) {
+	return hexutil.Bytes(p[:]).MarshalText()
+}
+
 // Point is a BLS field element.
 type Point [32]byte
 

internal/ethapi/api.go

@@ -1812,13 +1812,14 @@ func (s *TransactionAPI) SendTransaction(ctx context.Context, args TransactionAr
 // on a given unsigned transaction, and returns it to the caller for further
 // processing (signing + broadcast).
 func (s *TransactionAPI) FillTransaction(ctx context.Context, args TransactionArgs) (*SignTransactionResult, error) {
+	args.blobSidecarAllowed = true
+
 	// Set some sanity defaults and terminate on failure
 	if err := args.setDefaults(ctx, s.b); err != nil {
 		return nil, err
 	}
 	// Assemble the transaction and obtain rlp
 	tx := args.toTransaction()
-	// TODO(s1na): fill in blob proofs, commitments
 	data, err := tx.MarshalBinary()
 	if err != nil {
 		return nil, err

internal/ethapi/api_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/ecdsa"
+	"crypto/sha256"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -45,6 +46,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/internal/blocktest"
@@ -1079,6 +1081,195 @@ func TestSendBlobTransaction(t *testing.T) {
 	}
 }
 
+func TestFillBlobTransaction(t *testing.T) {
+	t.Parallel()
+	// Initialize test accounts
+	var (
+		key, _  = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
+		to      = crypto.PubkeyToAddress(key.PublicKey)
+		genesis = &core.Genesis{
+			Config: params.MergedTestChainConfig,
+			Alloc:  core.GenesisAlloc{},
+		}
+		emptyBlob                      = kzg4844.Blob{}
+		emptyBlobCommit, _             = kzg4844.BlobToCommitment(emptyBlob)
+		emptyBlobProof, _              = kzg4844.ComputeBlobProof(emptyBlob, emptyBlobCommit)
+		emptyBlobHash      common.Hash = kzg4844.CalcBlobHashV1(sha256.New(), &emptyBlobCommit)
+	)
+	b := newTestBackend(t, 1, genesis, beacon.New(ethash.NewFaker()), func(i int, b *core.BlockGen) {
+		b.SetPoS()
+	})
+	api := NewTransactionAPI(b, nil)
+	type result struct {
+		Hashes  []common.Hash
+		Sidecar *types.BlobTxSidecar
+	}
+	suite := []struct {
+		name string
+		args TransactionArgs
+		err  string
+		want *result
+	}{
+		{
+			name: "TestInvalidParamsCombination1",
+			args: TransactionArgs{
+				From:   &b.acc.Address,
+				To:     &to,
+				Value:  (*hexutil.Big)(big.NewInt(1)),
+				Blobs:  []kzg4844.Blob{{}},
+				Proofs: []kzg4844.Proof{{}},
+			},
+			err: `blob proofs provided while commitments were not`,
+		},
+		{
+			name: "TestInvalidParamsCombination2",
+			args: TransactionArgs{
+				From:        &b.acc.Address,
+				To:          &to,
+				Value:       (*hexutil.Big)(big.NewInt(1)),
+				Blobs:       []kzg4844.Blob{{}},
+				Commitments: []kzg4844.Commitment{{}},
+			},
+			err: `blob commitments provided while proofs were not`,
+		},
+		{
+			name: "TestInvalidParamsCount1",
+			args: TransactionArgs{
+				From:        &b.acc.Address,
+				To:          &to,
+				Value:       (*hexutil.Big)(big.NewInt(1)),
+				Blobs:       []kzg4844.Blob{{}},
+				Commitments: []kzg4844.Commitment{{}, {}},
+				Proofs:      []kzg4844.Proof{{}, {}},
+			},
+			err: `number of blobs and commitments mismatch (have=2, want=1)`,
+		},
+		{
+			name: "TestInvalidParamsCount2",
+			args: TransactionArgs{
+				From:        &b.acc.Address,
+				To:          &to,
+				Value:       (*hexutil.Big)(big.NewInt(1)),
+				Blobs:       []kzg4844.Blob{{}, {}},
+				Commitments: []kzg4844.Commitment{{}, {}},
+				Proofs:      []kzg4844.Proof{{}},
+			},
+			err: `number of blobs and proofs mismatch (have=1, want=2)`,
+		},
+		{
+			name: "TestInvalidProofVerification",
+			args: TransactionArgs{
+				From:        &b.acc.Address,
+				To:          &to,
+				Value:       (*hexutil.Big)(big.NewInt(1)),
+				Blobs:       []kzg4844.Blob{{}, {}},
+				Commitments: []kzg4844.Commitment{{}, {}},
+				Proofs:      []kzg4844.Proof{{}, {}},
+			},
+			err: `failed to verify blob proof: short buffer`,
+		},
+		{
+			name: "TestGenerateBlobHashes",
+			args: TransactionArgs{
+				From:        &b.acc.Address,
+				To:          &to,
+				Value:       (*hexutil.Big)(big.NewInt(1)),
+				Blobs:       []kzg4844.Blob{emptyBlob},
+				Commitments: []kzg4844.Commitment{emptyBlobCommit},
+				Proofs:      []kzg4844.Proof{emptyBlobProof},
+			},
+			want: &result{
+				Hashes: []common.Hash{emptyBlobHash},
+				Sidecar: &types.BlobTxSidecar{
+					Blobs:       []kzg4844.Blob{emptyBlob},
+					Commitments: []kzg4844.Commitment{emptyBlobCommit},
+					Proofs:      []kzg4844.Proof{emptyBlobProof},
+				},
+			},
+		},
+		{
+			name: "TestValidBlobHashes",
+			args: TransactionArgs{
+				From:        &b.acc.Address,
+				To:          &to,
+				Value:       (*hexutil.Big)(big.NewInt(1)),
+				BlobHashes:  []common.Hash{emptyBlobHash},
+				Blobs:       []kzg4844.Blob{emptyBlob},
+				Commitments: []kzg4844.Commitment{emptyBlobCommit},
+				Proofs:      []kzg4844.Proof{emptyBlobProof},
+			},
+			want: &result{
+				Hashes: []common.Hash{emptyBlobHash},
+				Sidecar: &types.BlobTxSidecar{
+					Blobs:       []kzg4844.Blob{emptyBlob},
+					Commitments: []kzg4844.Commitment{emptyBlobCommit},
+					Proofs:      []kzg4844.Proof{emptyBlobProof},
+				},
+			},
+		},
+		{
+			name: "TestInvalidBlobHashes",
+			args: TransactionArgs{
+				From:        &b.acc.Address,
+				To:          &to,
+				Value:       (*hexutil.Big)(big.NewInt(1)),
+				BlobHashes:  []common.Hash{{0x01, 0x22}},
+				Blobs:       []kzg4844.Blob{emptyBlob},
+				Commitments: []kzg4844.Commitment{emptyBlobCommit},
+				Proofs:      []kzg4844.Proof{emptyBlobProof},
+			},
+			err: fmt.Sprintf("blob hash verification failed (have=%s, want=%s)", common.Hash{0x01, 0x22}, emptyBlobHash),
+		},
+		{
+			name: "TestGenerateBlobProofs",
+			args: TransactionArgs{
+				From:  &b.acc.Address,
+				To:    &to,
+				Value: (*hexutil.Big)(big.NewInt(1)),
+				Blobs: []kzg4844.Blob{emptyBlob},
+			},
+			want: &result{
+				Hashes: []common.Hash{emptyBlobHash},
+				Sidecar: &types.BlobTxSidecar{
+					Blobs:       []kzg4844.Blob{emptyBlob},
+					Commitments: []kzg4844.Commitment{emptyBlobCommit},
+					Proofs:      []kzg4844.Proof{emptyBlobProof},
+				},
+			},
+		},
+	}
+	for _, tc := range suite {
+		t.Run(tc.name, func(t *testing.T) {
+			res, err := api.FillTransaction(context.Background(), tc.args)
+			if len(tc.err) > 0 {
+				if err == nil {
+					t.Fatalf("missing error. want: %s", tc.err)
+				} else if err != nil && err.Error() != tc.err {
+					t.Fatalf("error mismatch. want: %s, have: %s", tc.err, err.Error())
+				}
+				return
+			}
+			if err != nil && len(tc.err) == 0 {
+				t.Fatalf("expected no error. have: %s", err)
+			}
+			if res == nil {
+				t.Fatal("result missing")
+			}
+			want, err := json.Marshal(tc.want)
+			if err != nil {
+				t.Fatalf("failed to encode expected: %v", err)
+			}
+			have, err := json.Marshal(result{Hashes: res.Tx.BlobHashes(), Sidecar: res.Tx.BlobTxSidecar()})
+			if err != nil {
+				t.Fatalf("failed to encode computed sidecar: %v", err)
+			}
+			if !bytes.Equal(have, want) {
+				t.Errorf("blob sidecar mismatch. Have: %s, want: %s", have, want)
+			}
+		})
+	}
+}
+
 func argsFromTransaction(tx *types.Transaction, from common.Address) TransactionArgs {
 	var (
 		gas   = tx.Gas()

internal/ethapi/transaction_args.go

@@ -19,6 +19,7 @@ package ethapi
 import (
 	"bytes"
 	"context"
+	"crypto/sha256"
 	"errors"
 	"fmt"
 	"math/big"
@@ -29,11 +30,17 @@ import (
 	"github.com/ethereum/go-ethereum/consensus/misc/eip4844"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rpc"
 	"github.com/holiman/uint256"
 )
 
+var (
+	maxBlobsPerTransaction = params.MaxBlobGasPerBlock / params.BlobTxBlobGasPerBlob
+)
+
 // TransactionArgs represents the arguments to construct a new transaction
 // or a message call.
 type TransactionArgs struct {
@@ -56,9 +63,17 @@ type TransactionArgs struct {
 	AccessList *types.AccessList `json:"accessList,omitempty"`
 	ChainID    *hexutil.Big      `json:"chainId,omitempty"`
 
-	// Introduced by EIP-4844.
+	// For BlobTxType
 	BlobFeeCap *hexutil.Big  `json:"maxFeePerBlobGas"`
 	BlobHashes []common.Hash `json:"blobVersionedHashes,omitempty"`
+
+	// For BlobTxType transactions with blob sidecar
+	Blobs       []kzg4844.Blob       `json:"blobs"`
+	Commitments []kzg4844.Commitment `json:"commitments"`
+	Proofs      []kzg4844.Proof      `json:"proofs"`
+
+	// This configures whether blobs are allowed to be passed.
+	blobSidecarAllowed bool
 }
 
 // from retrieves the transaction sender address.
@@ -82,9 +97,13 @@ func (args *TransactionArgs) data() []byte {
 
 // setDefaults fills in default values for unspecified tx fields.
 func (args *TransactionArgs) setDefaults(ctx context.Context, b Backend) error {
+	if err := args.setBlobTxSidecar(ctx, b); err != nil {
+		return err
+	}
 	if err := args.setFeeDefaults(ctx, b); err != nil {
 		return err
 	}
+
 	if args.Value == nil {
 		args.Value = new(hexutil.Big)
 	}
@@ -98,15 +117,25 @@ func (args *TransactionArgs) setDefaults(ctx context.Context, b Backend) error {
 	if args.Data != nil && args.Input != nil && !bytes.Equal(*args.Data, *args.Input) {
 		return errors.New(`both "data" and "input" are set and not equal. Please use "input" to pass transaction call data`)
 	}
-	if args.BlobHashes != nil && args.To == nil {
-		return errors.New(`blob transactions cannot have the form of a create transaction`)
-	}
+
+	// BlobTx fields
 	if args.BlobHashes != nil && len(args.BlobHashes) == 0 {
 		return errors.New(`need at least 1 blob for a blob transaction`)
 	}
-	if args.To == nil && len(args.data()) == 0 {
+	if args.BlobHashes != nil && len(args.BlobHashes) > maxBlobsPerTransaction {
+		return fmt.Errorf(`too many blobs in transaction (have=%d, max=%d)`, len(args.BlobHashes), maxBlobsPerTransaction)
+	}
+
+	// create check
+	if args.To == nil {
+		if args.BlobHashes != nil {
+			return errors.New(`missing "to" in blob transaction`)
+		}
+		if len(args.data()) == 0 {
 			return errors.New(`contract creation without any data provided`)
 		}
+	}
+
 	// Estimate the gas usage if necessary.
 	if args.Gas == nil {
 		// These fields are immutable during the estimation, safe to
@@ -130,6 +159,7 @@ func (args *TransactionArgs) setDefaults(ctx context.Context, b Backend) error {
 		args.Gas = &estimated
 		log.Trace("Estimate gas usage automatically", "gas", args.Gas)
 	}
+
 	// If chain id is provided, ensure it matches the local chain id. Otherwise, set the local
 	// chain id as the default.
 	want := b.ChainConfig().ChainID
@@ -165,10 +195,12 @@ func (args *TransactionArgs) setFeeDefaults(ctx context.Context, b Backend) erro
 		}
 		return nil // No need to set anything, user already set MaxFeePerGas and MaxPriorityFeePerGas
 	}
+
 	// Sanity check the EIP-4844 fee parameters.
 	if args.BlobFeeCap != nil && args.BlobFeeCap.ToInt().Sign() == 0 {
 		return errors.New("maxFeePerBlobGas must be non-zero")
 	}
+
 	// Sanity check the non-EIP-1559 fee parameters.
 	head := b.CurrentHeader()
 	isLondon := b.ChainConfig().IsLondon(head.Number)
@@ -250,6 +282,81 @@ func (args *TransactionArgs) setLondonFeeDefaults(ctx context.Context, head *typ
 	return nil
 }
 
+// setBlobTxSidecar adds the blob tx
+func (args *TransactionArgs) setBlobTxSidecar(ctx context.Context, b Backend) error {
+	// No blobs, we're done.
+	if args.Blobs == nil {
+		return nil
+	}
+
+	// Passing blobs is not allowed in all contexts, only in specific methods.
+	if !args.blobSidecarAllowed {
+		return errors.New(`"blobs" is not supported for this RPC method`)
+	}
+
+	n := len(args.Blobs)
+	// Assume user provides either only blobs (w/o hashes), or
+	// blobs together with commitments and proofs.
+	if args.Commitments == nil && args.Proofs != nil {
+		return errors.New(`blob proofs provided while commitments were not`)
+	} else if args.Commitments != nil && args.Proofs == nil {
+		return errors.New(`blob commitments provided while proofs were not`)
+	}
+
+	// len(blobs) == len(commitments) == len(proofs) == len(hashes)
+	if args.Commitments != nil && len(args.Commitments) != n {
+		return fmt.Errorf("number of blobs and commitments mismatch (have=%d, want=%d)", len(args.Commitments), n)
+	}
+	if args.Proofs != nil && len(args.Proofs) != n {
+		return fmt.Errorf("number of blobs and proofs mismatch (have=%d, want=%d)", len(args.Proofs), n)
+	}
+	if args.BlobHashes != nil && len(args.BlobHashes) != n {
+		return fmt.Errorf("number of blobs and hashes mismatch (have=%d, want=%d)", len(args.BlobHashes), n)
+	}
+
+	if args.Commitments == nil {
+		// Generate commitment and proof.
+		commitments := make([]kzg4844.Commitment, n)
+		proofs := make([]kzg4844.Proof, n)
+		for i, b := range args.Blobs {
+			c, err := kzg4844.BlobToCommitment(b)
+			if err != nil {
+				return fmt.Errorf("blobs[%d]: error computing commitment: %v", i, err)
+			}
+			commitments[i] = c
+			p, err := kzg4844.ComputeBlobProof(b, c)
+			if err != nil {
+				return fmt.Errorf("blobs[%d]: error computing proof: %v", i, err)
+			}
+			proofs[i] = p
+		}
+		args.Commitments = commitments
+		args.Proofs = proofs
+	} else {
+		for i, b := range args.Blobs {
+			if err := kzg4844.VerifyBlobProof(b, args.Commitments[i], args.Proofs[i]); err != nil {
+				return fmt.Errorf("failed to verify blob proof: %v", err)
+			}
+		}
+	}
+
+	hashes := make([]common.Hash, n)
+	hasher := sha256.New()
+	for i, c := range args.Commitments {
+		hashes[i] = kzg4844.CalcBlobHashV1(hasher, &c)
+	}
+	if args.BlobHashes != nil {
+		for i, h := range hashes {
+			if h != args.BlobHashes[i] {
+				return fmt.Errorf("blob hash verification failed (have=%s, want=%s)", args.BlobHashes[i], h)
+			}
+		}
+	} else {
+		args.BlobHashes = hashes
+	}
+	return nil
+}
+
 // ToMessage converts the transaction arguments to the Message type used by the
 // core evm. This method is used in calls and traces that do not require a real
 // live transaction.
@@ -363,6 +470,14 @@ func (args *TransactionArgs) toTransaction() *types.Transaction {
 			BlobHashes: args.BlobHashes,
 			BlobFeeCap: uint256.MustFromBig((*big.Int)(args.BlobFeeCap)),
 		}
+		if args.Blobs != nil {
+			data.(*types.BlobTx).Sidecar = &types.BlobTxSidecar{
+				Blobs:       args.Blobs,
+				Commitments: args.Commitments,
+				Proofs:      args.Proofs,
+			}
+		}
+
 	case args.MaxFeePerGas != nil:
 		al := types.AccessList{}
 		if args.AccessList != nil {
@@ -379,6 +494,7 @@ func (args *TransactionArgs) toTransaction() *types.Transaction {
 			Data:       args.data(),
 			AccessList: al,
 		}
+
 	case args.AccessList != nil:
 		data = &types.AccessListTx{
 			To:         args.To,
@@ -390,6 +506,7 @@ func (args *TransactionArgs) toTransaction() *types.Transaction {
 			Data:       args.data(),
 			AccessList: *args.AccessList,
 		}
+
 	default:
 		data = &types.LegacyTx{
 			To:       args.To,
@@ -403,12 +520,6 @@ func (args *TransactionArgs) toTransaction() *types.Transaction {
 	return types.NewTx(data)
 }
 
-// ToTransaction converts the arguments to a transaction.
-// This assumes that setDefaults has been called.
-func (args *TransactionArgs) ToTransaction() *types.Transaction {
-	return args.toTransaction()
-}
-
 // IsEIP4844 returns an indicator if the args contains EIP4844 fields.
 func (args *TransactionArgs) IsEIP4844() bool {
 	return args.BlobHashes != nil || args.BlobFeeCap != nil