tests/fuzzers: fuzzbuzz fuzzers for keystore, rlp, trie, whisper (#19910)

* fuzzers: fuzzers for keystore, rlp, trie, whisper (cred to @guidovranken)

* fuzzers: move fuzzers to testdata

* testdata/fuzzers: documentation

* testdata/fuzzers: corpus for rlp

* tests/fuzzers: fixup

tests/fuzzers/trie/trie-fuzzer.go

@@ -0,0 +1,189 @@
+// 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 trie
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/ethdb/memorydb"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+// randTest performs random trie operations.
+// Instances of this test are created by Generate.
+type randTest []randTestStep
+
+type randTestStep struct {
+	op    int
+	key   []byte // for opUpdate, opDelete, opGet
+	value []byte // for opUpdate
+	err   error  // for debugging
+}
+
+type proofDb struct{}
+
+func (proofDb) Put(key []byte, value []byte) error {
+	return nil
+}
+
+func (proofDb) Delete(key []byte) error {
+	return nil
+}
+
+const (
+	opUpdate = iota
+	opDelete
+	opGet
+	opCommit
+	opHash
+	opReset
+	opItercheckhash
+	opProve
+	opMax // boundary value, not an actual op
+)
+
+type dataSource struct {
+	input  []byte
+	reader *bytes.Reader
+}
+
+func newDataSource(input []byte) *dataSource {
+	return &dataSource{
+		input, bytes.NewReader(input),
+	}
+}
+func (ds *dataSource) ReadByte() byte {
+	if b, err := ds.reader.ReadByte(); err != nil {
+		return 0
+	} else {
+		return b
+	}
+}
+func (ds *dataSource) Read(buf []byte) (int, error) {
+	return ds.reader.Read(buf)
+}
+func (ds *dataSource) Ended() bool {
+	return ds.reader.Len() == 0
+}
+
+func Generate(input []byte) randTest {
+
+	var allKeys [][]byte
+	r := newDataSource(input)
+	genKey := func() []byte {
+
+		if len(allKeys) < 2 || r.ReadByte() < 0x0f {
+			// new key
+			key := make([]byte, r.ReadByte()%50)
+			r.Read(key)
+			allKeys = append(allKeys, key)
+			return key
+		}
+		// use existing key
+		return allKeys[int(r.ReadByte())%len(allKeys)]
+	}
+
+	var steps randTest
+
+	for i := 0; !r.Ended(); i++ {
+
+		step := randTestStep{op: int(r.ReadByte()) % opMax}
+		switch step.op {
+		case opUpdate:
+			step.key = genKey()
+			step.value = make([]byte, 8)
+			binary.BigEndian.PutUint64(step.value, uint64(i))
+		case opGet, opDelete, opProve:
+			step.key = genKey()
+		}
+		steps = append(steps, step)
+		if len(steps) > 500 {
+			break
+		}
+	}
+
+	return steps
+}
+
+func Fuzz(input []byte) int {
+	program := Generate(input)
+	if len(program) == 0 {
+		return -1
+	}
+	if err := runRandTest(program); err != nil {
+		panic(err)
+	}
+	return 0
+}
+
+func runRandTest(rt randTest) error {
+
+	triedb := trie.NewDatabase(memorydb.New())
+
+	tr, _ := trie.New(common.Hash{}, triedb)
+	values := make(map[string]string) // tracks content of the trie
+
+	for i, step := range rt {
+		switch step.op {
+		case opUpdate:
+			tr.Update(step.key, step.value)
+			values[string(step.key)] = string(step.value)
+		case opDelete:
+			tr.Delete(step.key)
+			delete(values, string(step.key))
+		case opGet:
+			v := tr.Get(step.key)
+			want := values[string(step.key)]
+			if string(v) != want {
+				rt[i].err = fmt.Errorf("mismatch for key 0x%x, got 0x%x want 0x%x", step.key, v, want)
+			}
+		case opCommit:
+			_, rt[i].err = tr.Commit(nil)
+		case opHash:
+			tr.Hash()
+		case opReset:
+			hash, err := tr.Commit(nil)
+			if err != nil {
+				return err
+			}
+			newtr, err := trie.New(hash, triedb)
+			if err != nil {
+				return err
+			}
+			tr = newtr
+		case opItercheckhash:
+			checktr, _ := trie.New(common.Hash{}, triedb)
+			it := trie.NewIterator(tr.NodeIterator(nil))
+			for it.Next() {
+				checktr.Update(it.Key, it.Value)
+			}
+			if tr.Hash() != checktr.Hash() {
+				return fmt.Errorf("hash mismatch in opItercheckhash")
+			}
+		case opProve:
+			rt[i].err = tr.Prove(step.key, 0, proofDb{})
+		}
+		// Abort the test on error.
+		if rt[i].err != nil {
+			return rt[i].err
+		}
+	}
+	return nil
+}