Check kzg commitment for beacon-api propose block (#14702)

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

CHANGELOG.md

@@ -73,6 +73,7 @@ The format is based on Keep a Changelog, and this project adheres to Semantic Ve
 - Improvements to HTTP response handling. [pr](https://github.com/prysmaticlabs/prysm/pull/14673)
 - Updated `Blobs` endpoint to return additional metadata fields.
 - Made QUIC the default method to connect with peers.
+- Check kzg commitments align with blobs and proofs for beacon api end point.
 - Increase Max Payload Size in Gossip.
 
 ### Deprecated

beacon-chain/blockchain/kzg/BUILD.bazel

@@ -26,8 +26,7 @@ go_test(
     deps = [
         "//consensus-types/blocks:go_default_library",
         "//testing/require:go_default_library",
-        "@com_github_consensys_gnark_crypto//ecc/bls12-381/fr:go_default_library",
+        "//testing/util:go_default_library",
         "@com_github_crate_crypto_go_kzg_4844//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
     ],
 )

beacon-chain/blockchain/kzg/validation_test.go

@@ -1,51 +1,14 @@
 package kzg
 
 import (
-	"bytes"
-	"crypto/sha256"
-	"encoding/binary"
 	"testing"
 
-	"github.com/consensys/gnark-crypto/ecc/bls12-381/fr"
 	GoKZG "github.com/crate-crypto/go-kzg-4844"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	"github.com/sirupsen/logrus"
+	"github.com/prysmaticlabs/prysm/v5/testing/util"
 )
 
-func deterministicRandomness(seed int64) [32]byte {
-	// Converts an int64 to a byte slice
-	buf := new(bytes.Buffer)
-	err := binary.Write(buf, binary.BigEndian, seed)
-	if err != nil {
-		logrus.WithError(err).Error("Failed to write int64 to bytes buffer")
-		return [32]byte{}
-	}
-	bytes := buf.Bytes()
-
-	return sha256.Sum256(bytes)
-}
-
-// Returns a serialized random field element in big-endian
-func GetRandFieldElement(seed int64) [32]byte {
-	bytes := deterministicRandomness(seed)
-	var r fr.Element
-	r.SetBytes(bytes[:])
-
-	return GoKZG.SerializeScalar(r)
-}
-
-// Returns a random blob using the passed seed as entropy
-func GetRandBlob(seed int64) GoKZG.Blob {
-	var blob GoKZG.Blob
-	bytesPerBlob := GoKZG.ScalarsPerBlob * GoKZG.SerializedScalarSize
-	for i := 0; i < bytesPerBlob; i += GoKZG.SerializedScalarSize {
-		fieldElementBytes := GetRandFieldElement(seed + int64(i))
-		copy(blob[i:i+GoKZG.SerializedScalarSize], fieldElementBytes[:])
-	}
-	return blob
-}
-
 func GenerateCommitmentAndProof(blob GoKZG.Blob) (GoKZG.KZGCommitment, GoKZG.KZGProof, error) {
 	commitment, err := kzgContext.BlobToKZGCommitment(blob, 0)
 	if err != nil {
@@ -74,7 +37,7 @@ func TestBytesToAny(t *testing.T) {
 }
 
 func TestGenerateCommitmentAndProof(t *testing.T) {
-	blob := GetRandBlob(123)
+	blob := util.GetRandBlob(123)
 	commitment, proof, err := GenerateCommitmentAndProof(blob)
 	require.NoError(t, err)
 	expectedCommitment := GoKZG.KZGCommitment{180, 218, 156, 194, 59, 20, 10, 189, 186, 254, 132, 93, 7, 127, 104, 172, 238, 240, 237, 70, 83, 89, 1, 152, 99, 0, 165, 65, 143, 62, 20, 215, 230, 14, 205, 95, 28, 245, 54, 25, 160, 16, 178, 31, 232, 207, 38, 85}

beacon-chain/rpc/eth/beacon/BUILD.bazel

@@ -58,6 +58,7 @@ go_library(
         "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
+        "@com_github_ethereum_go_ethereum//crypto/kzg4844:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_fastssz//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
@@ -118,6 +119,7 @@ go_test(
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "//time/slots:go_default_library",
+        "@com_github_crate_crypto_go_kzg_4844//:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",

beacon-chain/rpc/eth/beacon/handlers.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 	"github.com/pkg/errors"
 	ssz "github.com/prysmaticlabs/fastssz"
 	"github.com/prysmaticlabs/prysm/v5/api"
@@ -1032,21 +1033,17 @@ func unmarshalStrict(data []byte, v interface{}) error {
 func (s *Server) validateBroadcast(ctx context.Context, r *http.Request, blk *eth.GenericSignedBeaconBlock) error {
 	switch r.URL.Query().Get(broadcastValidationQueryParam) {
 	case broadcastValidationConsensus:
-		b, err := blocks.NewSignedBeaconBlock(blk.Block)
+		if err := s.validateConsensus(ctx, blk); err != nil {
-		if err != nil {
-			return errors.Wrapf(err, "could not create signed beacon block")
-		}
-		if err = s.validateConsensus(ctx, b); err != nil {
 			return errors.Wrap(err, "consensus validation failed")
 		}
 	case broadcastValidationConsensusAndEquivocation:
+		if err := s.validateConsensus(r.Context(), blk); err != nil {
+			return errors.Wrap(err, "consensus validation failed")
+		}
 		b, err := blocks.NewSignedBeaconBlock(blk.Block)
 		if err != nil {
 			return errors.Wrapf(err, "could not create signed beacon block")
 		}
-		if err = s.validateConsensus(r.Context(), b); err != nil {
-			return errors.Wrap(err, "consensus validation failed")
-		}
 		if err = s.validateEquivocation(b.Block()); err != nil {
 			return errors.Wrap(err, "equivocation validation failed")
 		}
@@ -1056,7 +1053,12 @@ func (s *Server) validateBroadcast(ctx context.Context, r *http.Request, blk *et
 	return nil
 }
 
-func (s *Server) validateConsensus(ctx context.Context, blk interfaces.ReadOnlySignedBeaconBlock) error {
+func (s *Server) validateConsensus(ctx context.Context, b *eth.GenericSignedBeaconBlock) error {
+	blk, err := blocks.NewSignedBeaconBlock(b.Block)
+	if err != nil {
+		return errors.Wrapf(err, "could not create signed beacon block")
+	}
+
 	parentBlockRoot := blk.Block().ParentRoot()
 	parentBlock, err := s.Blocker.Block(ctx, parentBlockRoot[:])
 	if err != nil {
@@ -1076,6 +1078,24 @@ func (s *Server) validateConsensus(ctx context.Context, blk interfaces.ReadOnlyS
 	if err != nil {
 		return errors.Wrap(err, "could not execute state transition")
 	}
+
+	var blobs [][]byte
+	var proofs [][]byte
+	switch {
+	case blk.Version() == version.Electra:
+		blobs = b.GetElectra().Blobs
+		proofs = b.GetElectra().KzgProofs
+	case blk.Version() == version.Deneb:
+		blobs = b.GetDeneb().Blobs
+		proofs = b.GetDeneb().KzgProofs
+	default:
+		return nil
+	}
+
+	if err := s.validateBlobSidecars(blk, blobs, proofs); err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -1086,6 +1106,25 @@ func (s *Server) validateEquivocation(blk interfaces.ReadOnlyBeaconBlock) error
 	return nil
 }
 
+func (s *Server) validateBlobSidecars(blk interfaces.SignedBeaconBlock, blobs [][]byte, proofs [][]byte) error {
+	if blk.Version() < version.Deneb {
+		return nil
+	}
+	kzgs, err := blk.Block().Body().BlobKzgCommitments()
+	if err != nil {
+		return errors.Wrap(err, "could not get blob kzg commitments")
+	}
+	if len(blobs) != len(proofs) || len(blobs) != len(kzgs) {
+		return errors.New("number of blobs, proofs, and commitments do not match")
+	}
+	for i, blob := range blobs {
+		if err := kzg4844.VerifyBlobProof(kzg4844.Blob(blob), kzg4844.Commitment(kzgs[i]), kzg4844.Proof(proofs[i])); err != nil {
+			return errors.Wrap(err, "could not verify blob proof")
+		}
+	}
+	return nil
+}
+
 // GetBlockRoot retrieves the root of a block.
 func (s *Server) GetBlockRoot(w http.ResponseWriter, r *http.Request) {
 	ctx, span := trace.StartSpan(r.Context(), "beacon.GetBlockRoot")

beacon-chain/rpc/eth/beacon/handlers_test.go

@@ -12,6 +12,7 @@ import (
 	"testing"
 	"time"
 
+	GoKZG "github.com/crate-crypto/go-kzg-4844"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/go-bitfield"
@@ -33,6 +34,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v5/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v5/network/httputil"
 	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
@@ -2922,8 +2924,6 @@ func TestValidateConsensus(t *testing.T) {
 	require.NoError(t, err)
 	block, err := util.GenerateFullBlock(st, privs, util.DefaultBlockGenConfig(), st.Slot())
 	require.NoError(t, err)
-	sbb, err := blocks.NewSignedBeaconBlock(block)
-	require.NoError(t, err)
 	parentRoot, err := parentSbb.Block().HashTreeRoot()
 	require.NoError(t, err)
 	server := &Server{
@@ -2931,7 +2931,11 @@ func TestValidateConsensus(t *testing.T) {
 		Stater:  &testutil.MockStater{StatesByRoot: map[[32]byte]state.BeaconState{bytesutil.ToBytes32(parentBlock.Block.StateRoot): parentState}},
 	}
 
-	require.NoError(t, server.validateConsensus(ctx, sbb))
+	require.NoError(t, server.validateConsensus(ctx, &eth.GenericSignedBeaconBlock{
+		Block: &eth.GenericSignedBeaconBlock_Phase0{
+			Phase0: block,
+		},
+	}))
 }
 
 func TestValidateEquivocation(t *testing.T) {
@@ -4152,3 +4156,24 @@ func TestServer_broadcastBlobSidecars(t *testing.T) {
 	require.NoError(t, server.broadcastSeenBlockSidecars(context.Background(), blk, b.GetDeneb().Blobs, b.GetDeneb().KzgProofs))
 	require.LogsContain(t, hook, "Broadcasted blob sidecar for already seen block")
 }
+
+func Test_validateBlobSidecars(t *testing.T) {
+	blob := util.GetRandBlob(123)
+	commitment := GoKZG.KZGCommitment{180, 218, 156, 194, 59, 20, 10, 189, 186, 254, 132, 93, 7, 127, 104, 172, 238, 240, 237, 70, 83, 89, 1, 152, 99, 0, 165, 65, 143, 62, 20, 215, 230, 14, 205, 95, 28, 245, 54, 25, 160, 16, 178, 31, 232, 207, 38, 85}
+	proof := GoKZG.KZGProof{128, 110, 116, 170, 56, 111, 126, 87, 229, 234, 211, 42, 110, 150, 129, 206, 73, 142, 167, 243, 90, 149, 240, 240, 236, 204, 143, 182, 229, 249, 81, 27, 153, 171, 83, 70, 144, 250, 42, 1, 188, 215, 71, 235, 30, 7, 175, 86}
+	blk := util.NewBeaconBlockDeneb()
+	blk.Block.Body.BlobKzgCommitments = [][]byte{commitment[:]}
+	b, err := blocks.NewSignedBeaconBlock(blk)
+	require.NoError(t, err)
+	s := &Server{}
+	require.NoError(t, s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
+
+	require.ErrorContains(t, "number of blobs, proofs, and commitments do not match", s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{}))
+
+	sk, err := bls.RandKey()
+	require.NoError(t, err)
+	blk.Block.Body.BlobKzgCommitments = [][]byte{sk.PublicKey().Marshal()}
+	b, err = blocks.NewSignedBeaconBlock(blk)
+	require.NoError(t, err)
+	require.ErrorContains(t, "could not verify blob proof: can't verify opening proof", s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
+}

testing/util/BUILD.bazel

@@ -64,6 +64,8 @@ go_library(
         "//testing/assertions:go_default_library",
         "//testing/require:go_default_library",
         "//time/slots:go_default_library",
+        "@com_github_consensys_gnark_crypto//ecc/bls12-381/fr:go_default_library",
+        "@com_github_crate_crypto_go_kzg_4844//:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_ethereum_go_ethereum//core/types:go_default_library",

testing/util/deneb.go

@@ -1,10 +1,14 @@
 package util
 
 import (
+	"bytes"
+	"crypto/sha256"
 	"encoding/binary"
 	"math/big"
 	"testing"
 
+	"github.com/consensys/gnark-crypto/ecc/bls12-381/fr"
+	GoKZG "github.com/crate-crypto/go-kzg-4844"
 	"github.com/ethereum/go-ethereum/common"
 	gethTypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/signing"
@@ -19,6 +23,7 @@ import (
 	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 	"github.com/prysmaticlabs/prysm/v5/time/slots"
+	"github.com/sirupsen/logrus"
 )
 
 type DenebBlockGeneratorOption func(*denebBlockGenerator)
@@ -197,3 +202,36 @@ func ExtendBlocksPlusBlobs(t *testing.T, blks []blocks.ROBlock, size int) ([]blo
 
 	return blks, blobs
 }
+
+func deterministicRandomness(seed int64) [32]byte {
+	// Converts an int64 to a byte slice
+	buf := new(bytes.Buffer)
+	err := binary.Write(buf, binary.BigEndian, seed)
+	if err != nil {
+		logrus.WithError(err).Error("Failed to write int64 to bytes buffer")
+		return [32]byte{}
+	}
+	bytes := buf.Bytes()
+
+	return sha256.Sum256(bytes)
+}
+
+// Returns a serialized random field element in big-endian
+func GetRandFieldElement(seed int64) [32]byte {
+	bytes := deterministicRandomness(seed)
+	var r fr.Element
+	r.SetBytes(bytes[:])
+
+	return GoKZG.SerializeScalar(r)
+}
+
+// Returns a random blob using the passed seed as entropy
+func GetRandBlob(seed int64) GoKZG.Blob {
+	var blob GoKZG.Blob
+	bytesPerBlob := GoKZG.ScalarsPerBlob * GoKZG.SerializedScalarSize
+	for i := 0; i < bytesPerBlob; i += GoKZG.SerializedScalarSize {
+		fieldElementBytes := GetRandFieldElement(seed + int64(i))
+		copy(blob[i:i+GoKZG.SerializedScalarSize], fieldElementBytes[:])
+	}
+	return blob
+}