accounts: remove clique-specific signing method, replace with more generic

accounts/accounts.go

@@ -91,7 +91,7 @@ type Wallet interface {
 	// chain state reader.
 	SelfDerive(base DerivationPath, chain ethereum.ChainStateReader)
 
-	// SignCliqueHeader requests the wallet to sign the hash of a given Clique header
+	// SignData requests the wallet to sign the hash of the given data
 	// It looks up the account specified either solely via its address contained within,
 	// or optionally with the aid of any location metadata from the embedded URL field.
 	//
@@ -101,7 +101,7 @@ type Wallet interface {
 	// about which fields or actions are needed. The user may retry by providing
 	// the needed details via SignHashWithPassphrase, or by other means (e.g. unlock
 	// the account in a keystore).
-	SignCliqueHeader(account Account, header *types.Header) ([]byte, error)
+	SignData(account Account, mimeType string, data []byte) ([]byte, error)
 
 	// Signtext requests the wallet to sign the hash of a given piece of data, prefixed
 	// by the Ethereum prefix scheme

accounts/external/backend.go

@@ -18,6 +18,7 @@ package external
 
 import (
 	"fmt"
+	"github.com/ethereum/go-ethereum/crypto"
 	"math/big"
 	"sync"
 
@@ -151,11 +152,11 @@ func (api *ExternalSigner) signHash(account accounts.Account, hash []byte) ([]by
 	return []byte{}, fmt.Errorf("operation not supported on external signers")
 }
 
-// SignCliqueHeader implements accounts.Wallet, attempting to sign the given clique header
+// SignData signs keccak256(data). The mimetype parameter describes the type of data being signed
-func (api *ExternalSigner) SignCliqueHeader(account accounts.Account, header *types.Header) ([]byte, error) {
+func (api *ExternalSigner) SignData(account accounts.Account, mimeType string, data []byte) ([]byte, error) {
 	// TODO! Replace this with a call to clef SignData with correct mime-type for Clique, once we
 	// have that in place
-	return api.signHash(account, accounts.CliqueHash(header).Bytes())
+	return api.signHash(account, crypto.Keccak256(data))
 }
 
 func (api *ExternalSigner) SignText(account accounts.Account, text []byte) ([]byte, error) {

accounts/keystore/wallet.go

@@ -17,6 +17,7 @@
 package keystore
 
 import (
+	"github.com/ethereum/go-ethereum/crypto"
 	"math/big"
 
 	ethereum "github.com/ethereum/go-ethereum"
@@ -91,9 +92,9 @@ func (w *keystoreWallet) signHash(account accounts.Account, hash []byte) ([]byte
 	return w.keystore.SignHash(account, hash)
 }
 
-// SignCliqueHeader implements accounts.Wallet, attempting to sign the given clique header
+// SignData signs keccak256(data). The mimetype parameter describes the type of data being signed
-func (w *keystoreWallet) SignCliqueHeader(account accounts.Account, header *types.Header) ([]byte, error) {
+func (w *keystoreWallet) SignData(account accounts.Account, mimeType string, data []byte) ([]byte, error) {
-	return w.signHash(account, accounts.CliqueHash(header).Bytes())
+	return w.signHash(account, crypto.Keccak256(data))
 }
 
 func (w *keystoreWallet) SignText(account accounts.Account, text []byte) ([]byte, error) {

accounts/usbwallet/wallet.go

@@ -20,6 +20,7 @@ package usbwallet
 import (
 	"context"
 	"fmt"
+	"github.com/ethereum/go-ethereum/crypto"
 	"io"
 	"math/big"
 	"sync"
@@ -501,9 +502,9 @@ func (w *wallet) signHash(account accounts.Account, hash []byte) ([]byte, error)
 	return nil, accounts.ErrNotSupported
 }
 
-// SignCliqueHeader implements accounts.Wallet, attempting to sign the given clique header
+// SignData signs keccak256(data). The mimetype parameter describes the type of data being signed
-func (w *wallet) SignCliqueHeader(account accounts.Account, header *types.Header) ([]byte, error) {
+func (w *wallet) SignData(account accounts.Account, mimeType string, data []byte) ([]byte, error) {
-	return w.signHash(account, accounts.CliqueHash(header).Bytes())
+	return w.signHash(account, crypto.Keccak256(data))
 }
 
 func (w *wallet) SignText(account accounts.Account, text []byte) ([]byte, error) {

consensus/clique/clique.go

@@ -20,6 +20,8 @@ package clique
 import (
 	"bytes"
 	"errors"
+	"github.com/ethereum/go-ethereum/crypto/sha3"
+	"github.com/ethereum/go-ethereum/rlp"
 	"math/big"
 	"math/rand"
 	"sync"
@@ -136,7 +138,7 @@ var (
 
 // SignerFn is a signer callback function to request a header to be signed by a
 // backing account.
-type SignerFn func(accounts.Account, *types.Header) ([]byte, error)
+type SignerFn func(accounts.Account, string, []byte) ([]byte, error)
 
 // ecrecover extracts the Ethereum account address from a signed header.
 func ecrecover(header *types.Header, sigcache *lru.ARCCache) (common.Address, error) {
@@ -152,7 +154,7 @@ func ecrecover(header *types.Header, sigcache *lru.ARCCache) (common.Address, er
 	signature := header.Extra[len(header.Extra)-extraSeal:]
 
 	// Recover the public key and the Ethereum address
-	pubkey, err := crypto.Ecrecover(accounts.CliqueHash(header).Bytes(), signature)
+	pubkey, err := crypto.Ecrecover(SealHash(header).Bytes(), signature)
 	if err != nil {
 		return common.Address{}, err
 	}
@@ -613,7 +615,7 @@ func (c *Clique) Seal(chain consensus.ChainReader, block *types.Block, results c
 		log.Trace("Out-of-turn signing requested", "wiggle", common.PrettyDuration(wiggle))
 	}
 	// Sign all the things!
-	sighash, err := signFn(accounts.Account{Address: signer}, header)
+	sighash, err := signFn(accounts.Account{Address: signer}, "application/x-clique-header", CliqueRLP(header))
 	if err != nil {
 		return err
 	}
@@ -630,7 +632,7 @@ func (c *Clique) Seal(chain consensus.ChainReader, block *types.Block, results c
 		select {
 		case results <- block.WithSeal(header):
 		default:
-			log.Warn("Sealing result is not read by miner", "sealhash", c.SealHash(header))
+			log.Warn("Sealing result is not read by miner", "sealhash", SealHash(header))
 		}
 	}()
 
@@ -660,7 +662,31 @@ func CalcDifficulty(snap *Snapshot, signer common.Address) *big.Int {
 
 // SealHash returns the hash of a block prior to it being sealed.
 func (c *Clique) SealHash(header *types.Header) common.Hash {
-	return accounts.CliqueHash(header)
+	return SealHash(header)
+}
+
+// SealHash returns the hash of a block prior to it being sealed.
+func SealHash(header *types.Header) (hash common.Hash) {
+	hasher := sha3.NewKeccak256()
+	rlp.Encode(hasher, []interface{}{
+		header.ParentHash,
+		header.UncleHash,
+		header.Coinbase,
+		header.Root,
+		header.TxHash,
+		header.ReceiptHash,
+		header.Bloom,
+		header.Difficulty,
+		header.Number,
+		header.GasLimit,
+		header.GasUsed,
+		header.Time,
+		header.Extra[:len(header.Extra)-65], // Yes, this will panic if extra is too short
+		header.MixDigest,
+		header.Nonce,
+	})
+	hasher.Sum(hash[:0])
+	return hash
 }
 
 // Close implements consensus.Engine. It's a noop for clique as there are no background threads.
@@ -678,3 +704,31 @@ func (c *Clique) APIs(chain consensus.ChainReader) []rpc.API {
 		Public:    false,
 	}}
 }
+
+// CliqueRLP returns the rlp bytes which needs to be signed for the proof-of-authority
+// sealing. The RLP to sign consists of the entire header apart from the 65 byte signature
+// contained at the end of the extra data.
+//
+// Note, the method requires the extra data to be at least 65 bytes, otherwise it
+// panics. This is done to avoid accidentally using both forms (signature present
+// or not), which could be abused to produce different hashes for the same header.
+func CliqueRLP(header *types.Header) []byte {
+	data, _ := rlp.EncodeToBytes([]interface{}{
+		header.ParentHash,
+		header.UncleHash,
+		header.Coinbase,
+		header.Root,
+		header.TxHash,
+		header.ReceiptHash,
+		header.Bloom,
+		header.Difficulty,
+		header.Number,
+		header.GasLimit,
+		header.GasUsed,
+		header.Time,
+		header.Extra[:len(header.Extra)-65], // Yes, this will panic if extra is too short
+		header.MixDigest,
+		header.Nonce,
+	})
+	return data
+}

eth/backend.go

@@ -432,7 +432,7 @@ func (s *Ethereum) StartMining(threads int) error {
 				log.Error("Etherbase account unavailable locally", "err", err)
 				return fmt.Errorf("signer missing: %v", err)
 			}
-			clique.Authorize(eb, wallet.SignCliqueHeader)
+			clique.Authorize(eb, wallet.SignData)
 		}
 		// If mining is started, we can disable the transaction rejection mechanism
 		// introduced to speed sync times.