all: on-chain oracle checkpoint syncing (#19543)

* all: implement simple checkpoint syncing

cmd, les, node: remove callback mechanism

cmd, node: remove callback definition

les: simplify the registrar

les: expose checkpoint rpc services in the light client

les, light: don't store untrusted receipt

cmd, contracts, les: discard stale checkpoint

cmd, contracts/registrar: loose restriction of registeration

cmd, contracts: add replay-protection

all: off-chain multi-signature contract

params: deploy checkpoint contract for rinkeby

cmd/registrar: add raw signing mode for registrar

cmd/registrar, contracts/registrar, les: fixed messages

* cmd/registrar, contracts/registrar: fix lints

* accounts/abi/bind, les: address comments

* cmd, contracts, les, light, params: minor checkpoint sync cleanups

* cmd, eth, les, light: move checkpoint config to config file

* cmd, eth, les, params: address comments

* eth, les, params: address comments

* cmd: polish up the checkpoint admin CLI

* cmd, contracts, params: deploy new version contract

* cmd/checkpoint-admin: add another flag for clef mode signing

* cmd, contracts, les: rename and regen checkpoint oracle with abigen

1 files changed, 333 insertions, 0 deletions

diff --git a/contracts/checkpointoracle/oracle_test.go b/contracts/checkpointoracle/oracle_test.go
new file mode 100644
index 000000000..8c123a3b4
--- /dev/null
+++ b/contracts/checkpointoracle/oracle_test.go
@@ -0,0 +1,333 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package checkpointoracle
+
+import (
+	"bytes"
+	"crypto/ecdsa"
+	"encoding/binary"
+	"errors"
+	"math/big"
+	"reflect"
+	"sort"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/contracts/checkpointoracle/contract"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/params"
+)
+
+var (
+	emptyHash = [32]byte{}
+
+	checkpoint0 = params.TrustedCheckpoint{
+		SectionIndex: 0,
+		SectionHead:  common.HexToHash("0x7fa3c32f996c2bfb41a1a65b3d8ea3e0a33a1674cde43678ad6f4235e764d17d"),
+		CHTRoot:      common.HexToHash("0x98fc5d3de23a0fecebad236f6655533c157d26a1aedcd0852a514dc1169e6350"),
+		BloomRoot:    common.HexToHash("0x99b5adb52b337fe25e74c1c6d3835b896bd638611b3aebddb2317cce27a3f9fa"),
+	}
+	checkpoint1 = params.TrustedCheckpoint{
+		SectionIndex: 1,
+		SectionHead:  common.HexToHash("0x2d4dee68102125e59b0cc61b176bd89f0d12b3b91cfaf52ef8c2c82fb920c2d2"),
+		CHTRoot:      common.HexToHash("0x7d428008ece3b4c4ef5439f071930aad0bb75108d381308df73beadcd01ded95"),
+		BloomRoot:    common.HexToHash("0x652571f7736de17e7bbb427ac881474da684c6988a88bf51b10cca9a2ee148f4"),
+	}
+	checkpoint2 = params.TrustedCheckpoint{
+		SectionIndex: 2,
+		SectionHead:  common.HexToHash("0x61c0de578c0115b1dff8ef39aa600588c7c6ecb8a2f102003d7cf4c4146e9291"),
+		CHTRoot:      common.HexToHash("0x407a08a407a2bc3838b74ca3eb206903c9c8a186ccf5ef14af07794efff1970b"),
+		BloomRoot:    common.HexToHash("0x058b4161f558ce295a92925efc57f34f9210d5a30088d7475c183e0d3e58f5ac"),
+	}
+)
+
+var (
+	// The block frequency for creating checkpoint(only used in test)
+	sectionSize = big.NewInt(512)
+
+	// The number of confirmations needed to generate a checkpoint(only used in test).
+	processConfirms = big.NewInt(4)
+)
+
+// validateOperation executes the operation, watches and delivers all events fired by the backend and ensures the
+// correctness by assert function.
+func validateOperation(t *testing.T, c *contract.CheckpointOracle, backend *backends.SimulatedBackend, operation func(),
+	assert func(<-chan *contract.CheckpointOracleNewCheckpointVote) error, opName string) {
+	// Watch all events and deliver them to assert function
+	var (
+		sink   = make(chan *contract.CheckpointOracleNewCheckpointVote)
+		sub, _ = c.WatchNewCheckpointVote(nil, sink, nil)
+	)
+	defer func() {
+		// Close all subscribers
+		sub.Unsubscribe()
+	}()
+	operation()
+
+	// flush pending block
+	backend.Commit()
+	if err := assert(sink); err != nil {
+		t.Errorf("operation {%s} failed, err %s", opName, err)
+	}
+}
+
+// validateEvents checks that the correct number of contract events
+// fired by contract backend.
+func validateEvents(target int, sink interface{}) (bool, []reflect.Value) {
+	chanval := reflect.ValueOf(sink)
+	chantyp := chanval.Type()
+	if chantyp.Kind() != reflect.Chan || chantyp.ChanDir()&reflect.RecvDir == 0 {
+		return false, nil
+	}
+	count := 0
+	var recv []reflect.Value
+	timeout := time.After(1 * time.Second)
+	cases := []reflect.SelectCase{{Chan: chanval, Dir: reflect.SelectRecv}, {Chan: reflect.ValueOf(timeout), Dir: reflect.SelectRecv}}
+	for {
+		chose, v, _ := reflect.Select(cases)
+		if chose == 1 {
+			// Not enough event received
+			return false, nil
+		}
+		count += 1
+		recv = append(recv, v)
+		if count == target {
+			break
+		}
+	}
+	done := time.After(50 * time.Millisecond)
+	cases = cases[:1]
+	cases = append(cases, reflect.SelectCase{Chan: reflect.ValueOf(done), Dir: reflect.SelectRecv})
+	chose, _, _ := reflect.Select(cases)
+	// If chose equal 0, it means receiving redundant events.
+	return chose == 1, recv
+}
+
+func signCheckpoint(addr common.Address, privateKey *ecdsa.PrivateKey, index uint64, hash common.Hash) []byte {
+	// EIP 191 style signatures
+	//
+	// Arguments when calculating hash to validate
+	// 1: byte(0x19) - the initial 0x19 byte
+	// 2: byte(0) - the version byte (data with intended validator)
+	// 3: this - the validator address
+	// --  Application specific data
+	// 4 : checkpoint section_index(uint64)
+	// 5 : checkpoint hash (bytes32)
+	//     hash = keccak256(checkpoint_index, section_head, cht_root, bloom_root)
+	buf := make([]byte, 8)
+	binary.BigEndian.PutUint64(buf, index)
+	data := append([]byte{0x19, 0x00}, append(addr.Bytes(), append(buf, hash.Bytes()...)...)...)
+	sig, _ := crypto.Sign(crypto.Keccak256(data), privateKey)
+	sig[64] += 27 // Transform V from 0/1 to 27/28 according to the yellow paper
+	return sig
+}
+
+// assertSignature verifies whether the recovered signers are equal with expected.
+func assertSignature(addr common.Address, index uint64, hash [32]byte, r, s [32]byte, v uint8, expect common.Address) bool {
+	buf := make([]byte, 8)
+	binary.BigEndian.PutUint64(buf, index)
+	data := append([]byte{0x19, 0x00}, append(addr.Bytes(), append(buf, hash[:]...)...)...)
+	pubkey, err := crypto.Ecrecover(crypto.Keccak256(data), append(r[:], append(s[:], v-27)...))
+	if err != nil {
+		return false
+	}
+	var signer common.Address
+	copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
+	return bytes.Equal(signer.Bytes(), expect.Bytes())
+}
+
+type Account struct {
+	key  *ecdsa.PrivateKey
+	addr common.Address
+}
+type Accounts []Account
+
+func (a Accounts) Len() int           { return len(a) }
+func (a Accounts) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+func (a Accounts) Less(i, j int) bool { return bytes.Compare(a[i].addr.Bytes(), a[j].addr.Bytes()) < 0 }
+
+func TestCheckpointRegister(t *testing.T) {
+	// Initialize test accounts
+	var accounts Accounts
+	for i := 0; i < 3; i++ {
+		key, _ := crypto.GenerateKey()
+		addr := crypto.PubkeyToAddress(key.PublicKey)
+		accounts = append(accounts, Account{key: key, addr: addr})
+	}
+	sort.Sort(accounts)
+
+	// Deploy registrar contract
+	transactOpts := bind.NewKeyedTransactor(accounts[0].key)
+	contractBackend := backends.NewSimulatedBackend(core.GenesisAlloc{accounts[0].addr: {Balance: big.NewInt(1000000000)}, accounts[1].addr: {Balance: big.NewInt(1000000000)}, accounts[2].addr: {Balance: big.NewInt(1000000000)}}, 10000000)
+	// 3 trusted signers, threshold 2
+	contractAddr, _, c, err := contract.DeployCheckpointOracle(transactOpts, contractBackend, []common.Address{accounts[0].addr, accounts[1].addr, accounts[2].addr}, sectionSize, processConfirms, big.NewInt(2))
+	if err != nil {
+		t.Error("Failed to deploy registrar contract", err)
+	}
+	contractBackend.Commit()
+
+	// getRecent returns block height and hash of the head parent.
+	getRecent := func() (*big.Int, common.Hash) {
+		parentNumber := new(big.Int).Sub(contractBackend.Blockchain().CurrentHeader().Number, big.NewInt(1))
+		parentHash := contractBackend.Blockchain().CurrentHeader().ParentHash
+		return parentNumber, parentHash
+	}
+	// collectSig generates specified number signatures.
+	collectSig := func(index uint64, hash common.Hash, n int, unauthorized *ecdsa.PrivateKey) (v []uint8, r [][32]byte, s [][32]byte) {
+		for i := 0; i < n; i++ {
+			sig := signCheckpoint(contractAddr, accounts[i].key, index, hash)
+			if unauthorized != nil {
+				sig = signCheckpoint(contractAddr, unauthorized, index, hash)
+			}
+			r = append(r, common.BytesToHash(sig[:32]))
+			s = append(s, common.BytesToHash(sig[32:64]))
+			v = append(v, sig[64])
+		}
+		return v, r, s
+	}
+	// insertEmptyBlocks inserts a batch of empty blocks to blockchain.
+	insertEmptyBlocks := func(number int) {
+		for i := 0; i < number; i++ {
+			contractBackend.Commit()
+		}
+	}
+	// assert checks whether the current contract status is same with
+	// the expected.
+	assert := func(index uint64, hash [32]byte, height *big.Int) error {
+		lindex, lhash, lheight, err := c.GetLatestCheckpoint(nil)
+		if err != nil {
+			return err
+		}
+		if lindex != index {
+			return errors.New("latest checkpoint index mismatch")
+		}
+		if !bytes.Equal(lhash[:], hash[:]) {
+			return errors.New("latest checkpoint hash mismatch")
+		}
+		if lheight.Cmp(height) != 0 {
+			return errors.New("latest checkpoint height mismatch")
+		}
+		return nil
+	}
+
+	// Test future checkpoint registration
+	validateOperation(t, c, contractBackend, func() {
+		number, hash := getRecent()
+		v, r, s := collectSig(0, checkpoint0.Hash(), 2, nil)
+		c.SetCheckpoint(transactOpts, number, hash, checkpoint0.Hash(), 0, v, r, s)
+	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
+		return assert(0, emptyHash, big.NewInt(0))
+	}, "test future checkpoint registration")
+
+	insertEmptyBlocks(int(sectionSize.Uint64() + processConfirms.Uint64()))
+
+	// Test transaction replay protection
+	validateOperation(t, c, contractBackend, func() {
+		number, hash := getRecent()
+		v, r, s := collectSig(0, checkpoint0.Hash(), 2, nil)
+		hash = common.HexToHash("deadbeef")
+		c.SetCheckpoint(transactOpts, number, hash, checkpoint0.Hash(), 0, v, r, s)
+	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
+		return assert(0, emptyHash, big.NewInt(0))
+	}, "test transaction replay protection")
+
+	// Test unauthorized signature checking
+	validateOperation(t, c, contractBackend, func() {
+		number, hash := getRecent()
+		u, _ := crypto.GenerateKey()
+		v, r, s := collectSig(0, checkpoint0.Hash(), 2, u)
+		c.SetCheckpoint(transactOpts, number, hash, checkpoint0.Hash(), 0, v, r, s)
+	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
+		return assert(0, emptyHash, big.NewInt(0))
+	}, "test unauthorized signature checking")
+
+	// Test un-multi-signature checkpoint registration
+	validateOperation(t, c, contractBackend, func() {
+		number, hash := getRecent()
+		v, r, s := collectSig(0, checkpoint0.Hash(), 1, nil)
+		c.SetCheckpoint(transactOpts, number, hash, checkpoint0.Hash(), 0, v, r, s)
+	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
+		return assert(0, emptyHash, big.NewInt(0))
+	}, "test un-multi-signature checkpoint registration")
+
+	// Test valid checkpoint registration
+	validateOperation(t, c, contractBackend, func() {
+		number, hash := getRecent()
+		v, r, s := collectSig(0, checkpoint0.Hash(), 2, nil)
+		c.SetCheckpoint(transactOpts, number, hash, checkpoint0.Hash(), 0, v, r, s)
+	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
+		if valid, recv := validateEvents(2, events); !valid {
+			return errors.New("receive incorrect number of events")
+		} else {
+			for i := 0; i < len(recv); i++ {
+				event := recv[i].Interface().(*contract.CheckpointOracleNewCheckpointVote)
+				if !assertSignature(contractAddr, event.Index, event.CheckpointHash, event.R, event.S, event.V, accounts[i].addr) {
+					return errors.New("recover signer failed")
+				}
+			}
+		}
+		number, _ := getRecent()
+		return assert(0, checkpoint0.Hash(), number.Add(number, big.NewInt(1)))
+	}, "test valid checkpoint registration")
+
+	distance := 3*sectionSize.Uint64() + processConfirms.Uint64() - contractBackend.Blockchain().CurrentHeader().Number.Uint64()
+	insertEmptyBlocks(int(distance))
+
+	// Test uncontinuous checkpoint registration
+	validateOperation(t, c, contractBackend, func() {
+		number, hash := getRecent()
+		v, r, s := collectSig(2, checkpoint2.Hash(), 2, nil)
+		c.SetCheckpoint(transactOpts, number, hash, checkpoint2.Hash(), 2, v, r, s)
+	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
+		if valid, recv := validateEvents(2, events); !valid {
+			return errors.New("receive incorrect number of events")
+		} else {
+			for i := 0; i < len(recv); i++ {
+				event := recv[i].Interface().(*contract.CheckpointOracleNewCheckpointVote)
+				if !assertSignature(contractAddr, event.Index, event.CheckpointHash, event.R, event.S, event.V, accounts[i].addr) {
+					return errors.New("recover signer failed")
+				}
+			}
+		}
+		number, _ := getRecent()
+		return assert(2, checkpoint2.Hash(), number.Add(number, big.NewInt(1)))
+	}, "test uncontinuous checkpoint registration")
+
+	// Test old checkpoint registration
+	validateOperation(t, c, contractBackend, func() {
+		number, hash := getRecent()
+		v, r, s := collectSig(1, checkpoint1.Hash(), 2, nil)
+		c.SetCheckpoint(transactOpts, number, hash, checkpoint1.Hash(), 1, v, r, s)
+	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
+		number, _ := getRecent()
+		return assert(2, checkpoint2.Hash(), number)
+	}, "test uncontinuous checkpoint registration")
+
+	// Test stale checkpoint registration
+	validateOperation(t, c, contractBackend, func() {
+		number, hash := getRecent()
+		v, r, s := collectSig(2, checkpoint2.Hash(), 2, nil)
+		c.SetCheckpoint(transactOpts, number, hash, checkpoint2.Hash(), 2, v, r, s)
+	}, func(events <-chan *contract.CheckpointOracleNewCheckpointVote) error {
+		number, _ := getRecent()
+		return assert(2, checkpoint2.Hash(), number.Sub(number, big.NewInt(1)))
+	}, "test stale checkpoint registration")
+}