github.com/ethereum/go-ethereum@v1.16.1/tests/fuzzers/bls12381/precompile_fuzzer.go (about)

     1  // Copyright 2020 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package bls
    18  
    19  import (
    20  	"bytes"
    21  	"fmt"
    22  
    23  	"github.com/ethereum/go-ethereum/common"
    24  	"github.com/ethereum/go-ethereum/core/vm"
    25  )
    26  
    27  const (
    28  	blsG1Add      = byte(11)
    29  	blsG1MultiExp = byte(12)
    30  	blsG2Add      = byte(13)
    31  	blsG2MultiExp = byte(14)
    32  	blsPairing    = byte(15)
    33  	blsMapG1      = byte(16)
    34  	blsMapG2      = byte(17)
    35  )
    36  
    37  func checkInput(id byte, inputLen int) bool {
    38  	switch id {
    39  	case blsG1Add:
    40  		return inputLen == 256
    41  	case blsG1MultiExp:
    42  		return inputLen%160 == 0
    43  	case blsG2Add:
    44  		return inputLen == 512
    45  	case blsG2MultiExp:
    46  		return inputLen%288 == 0
    47  	case blsPairing:
    48  		return inputLen%384 == 0
    49  	case blsMapG1:
    50  		return inputLen == 64
    51  	case blsMapG2:
    52  		return inputLen == 128
    53  	}
    54  	panic("programmer error")
    55  }
    56  
    57  // The function must return
    58  //
    59  //   - 1 if the fuzzer should increase priority of the
    60  //     given input during subsequent fuzzing (for example, the input is lexically
    61  //     correct and was parsed successfully);
    62  //   - -1 if the input must not be added to corpus even if gives new coverage; and
    63  //   - 0 otherwise
    64  //
    65  // other values are reserved for future use.
    66  func fuzz(id byte, data []byte) int {
    67  	// Even on bad input, it should not crash, so we still test the gas calc
    68  	precompile := vm.PrecompiledContractsBLS[common.BytesToAddress([]byte{id})]
    69  	gas := precompile.RequiredGas(data)
    70  	if !checkInput(id, len(data)) {
    71  		return 0
    72  	}
    73  	// If the gas cost is too large (25M), bail out
    74  	if gas > 25*1000*1000 {
    75  		return 0
    76  	}
    77  	cpy := make([]byte, len(data))
    78  	copy(cpy, data)
    79  	_, err := precompile.Run(cpy)
    80  	if !bytes.Equal(cpy, data) {
    81  		panic(fmt.Sprintf("input data modified, precompile %d: %x %x", id, data, cpy))
    82  	}
    83  	if err != nil {
    84  		return 0
    85  	}
    86  	return 1
    87  }