tests/fuzzzers. eth/protocols/snap: add snap protocol fuzzers

eth/protocols/snap/handler.go

@@ -120,17 +120,17 @@ func MakeProtocols(backend Backend, dnsdisc enode.Iterator) []p2p.Protocol {
 // When this function terminates, the peer is disconnected.
 func handle(backend Backend, peer *Peer) error {
 	for {
-		if err := handleMessage(backend, peer); err != nil {
+		if err := HandleMessage(backend, peer); err != nil {
 			peer.Log().Debug("Message handling failed in `snap`", "err", err)
 			return err
 		}
 	}
 }
 
-// handleMessage is invoked whenever an inbound message is received from a
+// HandleMessage is invoked whenever an inbound message is received from a
 // remote peer on the `snap` protocol. The remote connection is torn down upon
 // returning any error.
-func handleMessage(backend Backend, peer *Peer) error {
+func HandleMessage(backend Backend, peer *Peer) error {
 	// Read the next message from the remote peer, and ensure it's fully consumed
 	msg, err := peer.rw.ReadMsg()
 	if err != nil {

eth/protocols/snap/peer.go

@@ -46,6 +46,16 @@ func newPeer(version uint, p *p2p.Peer, rw p2p.MsgReadWriter) *Peer {
 	}
 }
 
+// NewFakePeer create a fake snap peer without a backing p2p peer, for testing purposes.
+func NewFakePeer(version uint, id string, rw p2p.MsgReadWriter) *Peer {
+	return &Peer{
+		id:      id,
+		rw:      rw,
+		version: version,
+		logger:  log.New("peer", id[:8]),
+	}
+}
+
 // ID retrieves the peer's unique identifier.
 func (p *Peer) ID() string {
 	return p.id

oss-fuzz.sh

@@ -120,5 +120,10 @@ compile_fuzzer tests/fuzzers/bls12381  FuzzCrossG1MultiExp fuzz_cross_g1_multiex
 compile_fuzzer tests/fuzzers/bls12381  FuzzCrossG2Add fuzz_cross_g2_add
 compile_fuzzer tests/fuzzers/bls12381  FuzzCrossPairing fuzz_cross_pairing
 
+compile_fuzzer tests/fuzzers/snap  FuzzARange fuzz_account_range
+compile_fuzzer tests/fuzzers/snap  FuzzSRange fuzz_storage_range
+compile_fuzzer tests/fuzzers/snap  FuzzByteCodes fuzz_byte_codes
+compile_fuzzer tests/fuzzers/snap  FuzzTrieNodes fuzz_trie_nodes
+
 #TODO: move this to tests/fuzzers, if possible
 compile_fuzzer crypto/blake2b  Fuzz      fuzzBlake2b

tests/fuzzers/snap/debug/main.go

@@ -0,0 +1,39 @@
+// Copyright 2021 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 main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/ethereum/go-ethereum/tests/fuzzers/snap"
+)
+
+func main() {
+	if len(os.Args) != 2 {
+		fmt.Fprintf(os.Stderr, "Usage: debug <file>\n")
+		os.Exit(1)
+	}
+	crasher := os.Args[1]
+	data, err := ioutil.ReadFile(crasher)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error loading crasher %v: %v", crasher, err)
+		os.Exit(1)
+	}
+	snap.FuzzTrieNodes(data)
+}

tests/fuzzers/snap/fuzz_handler.go

@@ -0,0 +1,164 @@
+// Copyright 2021 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 snap
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"math/big"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/consensus/ethash"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/eth/protocols/snap"
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/params"
+	"github.com/ethereum/go-ethereum/rlp"
+	fuzz "github.com/google/gofuzz"
+)
+
+var trieRoot common.Hash
+
+func getChain() *core.BlockChain {
+	db := rawdb.NewMemoryDatabase()
+	ga := make(core.GenesisAlloc, 1000)
+	var a = make([]byte, 20)
+	var mkStorage = func(k, v int) (common.Hash, common.Hash) {
+		var kB = make([]byte, 32)
+		var vB = make([]byte, 32)
+		binary.LittleEndian.PutUint64(kB, uint64(k))
+		binary.LittleEndian.PutUint64(vB, uint64(v))
+		return common.BytesToHash(kB), common.BytesToHash(vB)
+	}
+	storage := make(map[common.Hash]common.Hash)
+	for i := 0; i < 10; i++ {
+		k, v := mkStorage(i, i)
+		storage[k] = v
+	}
+	for i := 0; i < 1000; i++ {
+		binary.LittleEndian.PutUint64(a, uint64(i+0xff))
+		acc := core.GenesisAccount{Balance: big.NewInt(int64(i))}
+		if i%2 == 1 {
+			acc.Storage = storage
+		}
+		ga[common.BytesToAddress(a)] = acc
+	}
+	gspec := core.Genesis{
+		Config: params.TestChainConfig,
+		Alloc:  ga,
+	}
+	genesis := gspec.MustCommit(db)
+	blocks, _ := core.GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 2,
+		func(i int, gen *core.BlockGen) {})
+	cacheConf := &core.CacheConfig{
+		TrieCleanLimit:      0,
+		TrieDirtyLimit:      0,
+		TrieTimeLimit:       5 * time.Minute,
+		TrieCleanNoPrefetch: true,
+		TrieCleanRejournal:  0,
+		SnapshotLimit:       100,
+		SnapshotWait:        true,
+	}
+	trieRoot = blocks[len(blocks)-1].Root()
+	bc, _ := core.NewBlockChain(db, cacheConf, gspec.Config, ethash.NewFaker(), vm.Config{}, nil, nil)
+	if _, err := bc.InsertChain(blocks); err != nil {
+		panic(err)
+	}
+	return bc
+}
+
+type dummyBackend struct {
+	chain *core.BlockChain
+}
+
+func (d *dummyBackend) Chain() *core.BlockChain                { return d.chain }
+func (d *dummyBackend) RunPeer(*snap.Peer, snap.Handler) error { return nil }
+func (d *dummyBackend) PeerInfo(enode.ID) interface{}          { return "Foo" }
+func (d *dummyBackend) Handle(*snap.Peer, snap.Packet) error   { return nil }
+
+type dummyRW struct {
+	code       uint64
+	data       []byte
+	writeCount int
+}
+
+func (d *dummyRW) ReadMsg() (p2p.Msg, error) {
+	return p2p.Msg{
+		Code:       d.code,
+		Payload:    bytes.NewReader(d.data),
+		ReceivedAt: time.Now(),
+		Size:       uint32(len(d.data)),
+	}, nil
+}
+
+func (d *dummyRW) WriteMsg(msg p2p.Msg) error {
+	d.writeCount++
+	return nil
+}
+
+func doFuzz(input []byte, obj interface{}, code int) int {
+	if len(input) > 1024*4 {
+		return -1
+	}
+	bc := getChain()
+	defer bc.Stop()
+	backend := &dummyBackend{bc}
+	fuzz.NewFromGoFuzz(input).Fuzz(obj)
+	var data []byte
+	switch p := obj.(type) {
+	case *snap.GetTrieNodesPacket:
+		p.Root = trieRoot
+		data, _ = rlp.EncodeToBytes(obj)
+	default:
+		data, _ = rlp.EncodeToBytes(obj)
+	}
+	cli := &dummyRW{
+		code: uint64(code),
+		data: data,
+	}
+	peer := snap.NewFakePeer(65, "gazonk01", cli)
+	err := snap.HandleMessage(backend, peer)
+	switch {
+	case err == nil && cli.writeCount != 1:
+		panic(fmt.Sprintf("Expected 1 response, got %d", cli.writeCount))
+	case err != nil && cli.writeCount != 0:
+		panic(fmt.Sprintf("Expected 0 response, got %d", cli.writeCount))
+	}
+	return 1
+}
+
+// To run a fuzzer, do
+// $ CGO_ENABLED=0 go-fuzz-build -func FuzzTrieNodes
+// $ go-fuzz
+
+func FuzzARange(input []byte) int {
+	return doFuzz(input, &snap.GetAccountRangePacket{}, snap.GetAccountRangeMsg)
+}
+func FuzzSRange(input []byte) int {
+	return doFuzz(input, &snap.GetStorageRangesPacket{}, snap.GetStorageRangesMsg)
+}
+func FuzzByteCodes(input []byte) int {
+	return doFuzz(input, &snap.GetByteCodesPacket{}, snap.GetByteCodesMsg)
+}
+func FuzzTrieNodes(input []byte) int {
+	return doFuzz(input, &snap.GetTrieNodesPacket{}, snap.GetTrieNodesMsg)
+}