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/rlp/rlp_fuzzer.go

@@ -0,0 +1,127 @@
+// 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 rlp
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/rlp"
+)
+
+func decodeEncode(input []byte, val interface{}, i int) {
+	if err := rlp.DecodeBytes(input, val); err == nil {
+		output, err := rlp.EncodeToBytes(val)
+		if err != nil {
+			panic(err)
+		}
+		if !bytes.Equal(input, output) {
+			panic(fmt.Sprintf("case %d: encode-decode is not equal, \ninput : %x\noutput: %x", i, input, output))
+		}
+	}
+}
+
+func Fuzz(input []byte) int {
+	var i int
+	{
+		if len(input) > 0 {
+			rlp.Split(input)
+		}
+	}
+	{
+		if len(input) > 0 {
+			if elems, _, err := rlp.SplitList(input); err == nil {
+				rlp.CountValues(elems)
+			}
+		}
+	}
+
+	{
+		rlp.NewStream(bytes.NewReader(input), 0).Decode(new(interface{}))
+	}
+
+	{
+		decodeEncode(input, new(interface{}), i)
+		i++
+	}
+	{
+		var v struct {
+			Int    uint
+			String string
+			Bytes  []byte
+		}
+		decodeEncode(input, &v, i)
+		i++
+	}
+
+	{
+		type Types struct {
+			Bool  bool
+			Raw   rlp.RawValue
+			Slice []*Types
+			Iface []interface{}
+		}
+		var v Types
+		decodeEncode(input, &v, i)
+		i++
+	}
+	{
+		type AllTypes struct {
+			Int    uint
+			String string
+			Bytes  []byte
+			Bool   bool
+			Raw    rlp.RawValue
+			Slice  []*AllTypes
+			Array  [3]*AllTypes
+			Iface  []interface{}
+		}
+		var v AllTypes
+		decodeEncode(input, &v, i)
+		i++
+	}
+	{
+		decodeEncode(input, [10]byte{}, i)
+		i++
+	}
+	{
+		var v struct {
+			Byte [10]byte
+			Rool [10]bool
+		}
+		decodeEncode(input, &v, i)
+		i++
+	}
+	{
+		var h types.Header
+		decodeEncode(input, &h, i)
+		i++
+		var b types.Block
+		decodeEncode(input, &b, i)
+		i++
+		var t types.Transaction
+		decodeEncode(input, &t, i)
+		i++
+		var txs types.Transactions
+		decodeEncode(input, &txs, i)
+		i++
+		var rs types.Receipts
+		decodeEncode(input, &rs, i)
+	}
+	return 0
+}