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Unverified Commit 15b7e0b2 authored by Martin Holst Swende's avatar Martin Holst Swende Committed by GitHub
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common/math, tests/fuzzers: use big.Int clone (#26006) 

* common/math, tests/fuzzers: use big.Int clone

* common/math: license
parent fb75f11e
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Showing with 110 additions and 92 deletions
common/math/modexp.go deleted 100644 → 0
View file @ fb75f11e
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package math
import (
"math/big"
"math/bits"
"github.com/ethereum/go-ethereum/common"
)
// FastExp is semantically equivalent to x.Exp(x,y, m), but is faster for even
// modulus.
func FastExp(x, y, m *big.Int) *big.Int {
// Split m = m1 × m2 where m1 = 2ⁿ
n := m.TrailingZeroBits()
m1 := new(big.Int).Lsh(common.Big1, n)
mask := new(big.Int).Sub(m1, common.Big1)
m2 := new(big.Int).Rsh(m, n)
// We want z = x**y mod m.
// z1 = x**y mod m1 = (x**y mod m) mod m1 = z mod m1
// z2 = x**y mod m2 = (x**y mod m) mod m2 = z mod m2
z1 := fastExpPow2(x, y, mask)
z2 := new(big.Int).Exp(x, y, m2)
// Reconstruct z from z1, z2 using CRT, using algorithm from paper,
// which uses only a single modInverse.
// p = (z1 - z2) * m2⁻¹ (mod m1)
// z = z2 + p * m2
z := new(big.Int).Set(z2)
// Compute (z1 - z2) mod m1 [m1 == 2**n] into z1.
z1 = z1.And(z1, mask)
z2 = z2.And(z2, mask)
z1 = z1.Sub(z1, z2)
if z1.Sign() < 0 {
z1 = z1.Add(z1, m1)
}
// Reuse z2 for p = z1 * m2inv.
m2inv := new(big.Int).ModInverse(m2, m1)
z2 = z2.Mul(z1, m2inv)
z2 = z2.And(z2, mask)
// Reuse z1 for m2 * p.
z = z.Add(z, z1.Mul(z2, m2))
z = z.Rem(z, m)
return z
}
func fastExpPow2(x, y *big.Int, mask *big.Int) *big.Int {
z := big.NewInt(1)
if y.Sign() == 0 {
return z
}
p := new(big.Int).Set(x)
p = p.And(p, mask)
if p.Cmp(z) <= 0 { // p <= 1
return p
}
if y.Cmp(mask) > 0 {
y = new(big.Int).And(y, mask)
}
t := new(big.Int)
for _, b := range y.Bits() {
for i := 0; i < bits.UintSize; i++ {
if b&1 != 0 {
z, t = t.Mul(z, p), z
z = z.And(z, mask)
}
p, t = t.Mul(p, p), p
p = p.And(p, mask)
b >>= 1
}
}
return z
}
common/math/modexp_test.go 0 → 100644
View file @ 15b7e0b2
// Copyright 2022 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 math
import (
"math/big"
"testing"
big2 "github.com/holiman/big"
)
// TestFastModexp tests some cases found during fuzzing.
func TestFastModexp(t *testing.T) {
for i, tc := range []struct {
base string
exp string
mod string
}{
{"0xeffffff900002f00", "0x40000000000000", "0x200"},
{"0xf000", "0x4f900b400080000", "0x400000d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9d9ffffff005aeffd310000000000000000000000000000000000009f9f9f9f0000000000000000000000000800000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000befffa5a5a5fff900002f000040000000000000000000000000000000029d9d9d000000000000009f9f9f00000000000000009f9f9f000000f3a080ab00000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f0000000000002900009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f000000cf000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f000000000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000befffff0000c0800000000800000000000000000000000000000002000000000000009f9f9f0000000000000000008000ff000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000befffa5a5a5fff900002f000040000000000000000000000000000000029d9d9d000000000000009f9f9f00000000000000009f9f9f000000f3a080ab00000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f0000000000002900009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f000000000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f000000000000000000000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000beffffff900002f0000400000c100000000000000000000000000000000000000006160600000000000000000008000ff0000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f00000000000000009f9f0000"},
{"5", "1435700818", "72"},
{"0xffff", "0x300030003000300030003000300030003000302a3000300030003000300030003000300030003000300030003000300030003030623066307f3030783062303430383064303630343036", "0x300000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"},
{"0x3133", "0x667f00000000000000000000000000ff002a000000000000000000000000000000000000000000000000000000000000667fff30783362773057ee756a6c266134643831646230313630", "0x3030000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"},
} {
var (
base, _ = new(big.Int).SetString(tc.base, 0)
exp, _ = new(big.Int).SetString(tc.exp, 0)
mod, _ = new(big.Int).SetString(tc.mod, 0)
base2, _ = new(big2.Int).SetString(tc.base, 0)
exp2, _ = new(big2.Int).SetString(tc.exp, 0)
mod2, _ = new(big2.Int).SetString(tc.mod, 0)
)
var a = new(big2.Int).Exp(base2, exp2, mod2).String()
var b = new(big.Int).Exp(base, exp, mod).String()
if a != b {
t.Errorf("test %d: %#x ^ %#x mod %#x \n have %x\n want %x", i, base, exp, mod, a, b)
}
}
}
go.mod
View file @ 15b7e0b2
......@@ -33,6 +33,7 @@ require (
github.com/graph-gophers/graphql-go v1.3.0
github.com/hashicorp/go-bexpr v0.1.10
github.com/hashicorp/golang-lru v0.5.5-0.20210104140557-80c98217689d
github.com/holiman/big v0.0.0-20221017200358-a027dc42d04e
github.com/holiman/bloomfilter/v2 v2.0.3
github.com/holiman/uint256 v1.2.0
github.com/huin/goupnp v1.0.3
......@@ -60,7 +61,7 @@ require (
golang.org/x/crypto v0.0.0-20210921155107-089bfa567519
golang.org/x/mobile v0.0.0-20190719004257-d2bd2a29d028
golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a
golang.org/x/sys v0.0.0-20221013171732-95e765b1cc43
golang.org/x/term v0.0.0-20210927222741-03fcf44c2211
golang.org/x/text v0.3.7
golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba
......
go.sum
View file @ 15b7e0b2
......@@ -223,6 +223,8 @@ github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ
github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
github.com/hashicorp/golang-lru v0.5.5-0.20210104140557-80c98217689d h1:dg1dEPuWpEqDnvIw251EVy4zlP8gWbsGj4BsUKCRpYs=
github.com/hashicorp/golang-lru v0.5.5-0.20210104140557-80c98217689d/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
github.com/holiman/big v0.0.0-20221017200358-a027dc42d04e h1:pIYdhNkDh+YENVNi3gto8n9hAmRxKxoar0iE6BLucjw=
github.com/holiman/big v0.0.0-20221017200358-a027dc42d04e/go.mod h1:j9cQbcqHQujT0oKJ38PylVfqohClLr3CvDC+Qcg+lhU=
github.com/holiman/bloomfilter/v2 v2.0.3 h1:73e0e/V0tCydx14a0SCYS/EWCxgwLZ18CZcZKVu0fao=
github.com/holiman/bloomfilter/v2 v2.0.3/go.mod h1:zpoh+gs7qcpqrHr3dB55AMiJwo0iURXE7ZOP9L9hSkA=
github.com/holiman/uint256 v1.2.0 h1:gpSYcPLWGv4sG43I2mVLiDZCNDh/EpGjSk8tmtxitHM=
......@@ -552,8 +554,9 @@ golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBc
golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20211020174200-9d6173849985/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220517195934-5e4e11fc645e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a h1:dGzPydgVsqGcTRVwiLJ1jVbufYwmzD3LfVPLKsKg+0k=
golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20221013171732-95e765b1cc43 h1:OK7RB6t2WQX54srQQYSXMW8dF5C6/8+oA/s5QBmmto4=
golang.org/x/sys v0.0.0-20221013171732-95e765b1cc43/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 h1:JGgROgKl9N8DuW20oFS5gxc+lE67/N3FcwmBPMe7ArY=
......
tests/fuzzers/modexp/debug/main.go 0 → 100644
View file @ 15b7e0b2
// Copyright 2020 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"
"os"
"github.com/ethereum/go-ethereum/tests/fuzzers/modexp"
)
func main() {
if len(os.Args) != 2 {
fmt.Fprintf(os.Stderr, "Usage: debug <file>\n")
fmt.Fprintf(os.Stderr, "Example\n")
fmt.Fprintf(os.Stderr, " $ debug ../crashers/4bbef6857c733a87ecf6fd8b9e7238f65eb9862a\n")
os.Exit(1)
}
crasher := os.Args[1]
data, err := os.ReadFile(crasher)
if err != nil {
fmt.Fprintf(os.Stderr, "error loading crasher %v: %v", crasher, err)
os.Exit(1)
}
modexp.Fuzz(data)
}
tests/fuzzers/modexp/modexp-fuzzer.go
View file @ 15b7e0b2
......@@ -21,8 +21,8 @@ import (
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/core/vm"
big2 "github.com/holiman/big"
)
// Fuzz is the fuzzing entry-point.
......@@ -56,18 +56,21 @@ func Fuzz(input []byte) int {
input = input[96:]
// Retrieve the operands and execute the exponentiation
var (
base = new(big.Int).SetBytes(getData(input, 0, baseLen))
exp = new(big.Int).SetBytes(getData(input, baseLen, expLen))
mod = new(big.Int).SetBytes(getData(input, baseLen+expLen, modLen))
base = new(big.Int).SetBytes(getData(input, 0, baseLen))
exp = new(big.Int).SetBytes(getData(input, baseLen, expLen))
mod = new(big.Int).SetBytes(getData(input, baseLen+expLen, modLen))
base2 = new(big2.Int).SetBytes(getData(input, 0, baseLen))
exp2 = new(big2.Int).SetBytes(getData(input, baseLen, expLen))
mod2 = new(big2.Int).SetBytes(getData(input, baseLen+expLen, modLen))
)
if mod.BitLen() == 0 {
// Modulo 0 is undefined, return zero
return -1
}
var a = math.FastExp(new(big.Int).Set(base), new(big.Int).Set(exp), new(big.Int).Set(mod))
var b = base.Exp(base, exp, mod)
if a.Cmp(b) != 0 {
panic(fmt.Sprintf("Inequality %x != %x", a, b))
var a = new(big2.Int).Exp(base2, exp2, mod2).String()
var b = new(big.Int).Exp(base, exp, mod).String()
if a != b {
panic(fmt.Sprintf("Inequality %#x ^ %#x mod %#x \n have %s\n want %s", base, exp, mod, a, b))
}
return 1
}
......
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