path: root/contracts/checkpointoracle/oracle_test.go

// Copyright 2019 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
    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)
    defer contractBackend.Close()

    transactOpts := bind.NewKeyedTransactor(accounts[0].key)

    // 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, _ := 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")
}