| // Copyright 2019 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 big_test |
| |
| import ( |
| cryptorand "crypto/rand" |
| "math/big" |
| "math/rand" |
| "reflect" |
| "testing" |
| "testing/quick" |
| ) |
| |
| func equal(z, x *big.Int) bool { |
| return z.Cmp(x) == 0 |
| } |
| |
| type bigInt struct { |
| *big.Int |
| } |
| |
| func generatePositiveInt(rand *rand.Rand, size int) *big.Int { |
| n := big.NewInt(1) |
| n.Lsh(n, uint(rand.Intn(size*8))) |
| n.Rand(rand, n) |
| return n |
| } |
| |
| func (bigInt) Generate(rand *rand.Rand, size int) reflect.Value { |
| n := generatePositiveInt(rand, size) |
| if rand.Intn(4) == 0 { |
| n.Neg(n) |
| } |
| return reflect.ValueOf(bigInt{n}) |
| } |
| |
| type notZeroInt struct { |
| *big.Int |
| } |
| |
| func (notZeroInt) Generate(rand *rand.Rand, size int) reflect.Value { |
| n := generatePositiveInt(rand, size) |
| if rand.Intn(4) == 0 { |
| n.Neg(n) |
| } |
| if n.Sign() == 0 { |
| n.SetInt64(1) |
| } |
| return reflect.ValueOf(notZeroInt{n}) |
| } |
| |
| type positiveInt struct { |
| *big.Int |
| } |
| |
| func (positiveInt) Generate(rand *rand.Rand, size int) reflect.Value { |
| n := generatePositiveInt(rand, size) |
| return reflect.ValueOf(positiveInt{n}) |
| } |
| |
| type prime struct { |
| *big.Int |
| } |
| |
| func (prime) Generate(r *rand.Rand, size int) reflect.Value { |
| n, err := cryptorand.Prime(r, r.Intn(size*8-2)+2) |
| if err != nil { |
| panic(err) |
| } |
| return reflect.ValueOf(prime{n}) |
| } |
| |
| type zeroOrOne struct { |
| uint |
| } |
| |
| func (zeroOrOne) Generate(rand *rand.Rand, size int) reflect.Value { |
| return reflect.ValueOf(zeroOrOne{uint(rand.Intn(2))}) |
| } |
| |
| type smallUint struct { |
| uint |
| } |
| |
| func (smallUint) Generate(rand *rand.Rand, size int) reflect.Value { |
| return reflect.ValueOf(smallUint{uint(rand.Intn(1024))}) |
| } |
| |
| // checkAliasingOneArg checks if f returns a correct result when v and x alias. |
| // |
| // f is a function that takes x as an argument, doesn't modify it, sets v to the |
| // result, and returns v. It is the function signature of unbound methods like |
| // |
| // func (v *big.Int) m(x *big.Int) *big.Int |
| // |
| // v and x are two random Int values. v is randomized even if it will be |
| // overwritten to test for improper buffer reuse. |
| func checkAliasingOneArg(t *testing.T, f func(v, x *big.Int) *big.Int, v, x *big.Int) bool { |
| x1, v1 := new(big.Int).Set(x), new(big.Int).Set(x) |
| |
| // Calculate a reference f(x) without aliasing. |
| if out := f(v, x); out != v { |
| return false |
| } |
| |
| // Test aliasing the argument and the receiver. |
| if out := f(v1, v1); out != v1 || !equal(v1, v) { |
| t.Logf("f(v, x) != f(x, x)") |
| return false |
| } |
| |
| // Ensure the arguments was not modified. |
| return equal(x, x1) |
| } |
| |
| // checkAliasingTwoArgs checks if f returns a correct result when any |
| // combination of v, x and y alias. |
| // |
| // f is a function that takes x and y as arguments, doesn't modify them, sets v |
| // to the result, and returns v. It is the function signature of unbound methods |
| // like |
| // |
| // func (v *big.Int) m(x, y *big.Int) *big.Int |
| // |
| // v, x and y are random Int values. v is randomized even if it will be |
| // overwritten to test for improper buffer reuse. |
| func checkAliasingTwoArgs(t *testing.T, f func(v, x, y *big.Int) *big.Int, v, x, y *big.Int) bool { |
| x1, y1, v1 := new(big.Int).Set(x), new(big.Int).Set(y), new(big.Int).Set(v) |
| |
| // Calculate a reference f(x, y) without aliasing. |
| if out := f(v, x, y); out == nil { |
| // Certain functions like ModInverse return nil for certain inputs. |
| // Check that receiver and arguments were unchanged and move on. |
| return equal(x, x1) && equal(y, y1) && equal(v, v1) |
| } else if out != v { |
| return false |
| } |
| |
| // Test aliasing the first argument and the receiver. |
| v1.Set(x) |
| if out := f(v1, v1, y); out != v1 || !equal(v1, v) { |
| t.Logf("f(v, x, y) != f(x, x, y)") |
| return false |
| } |
| // Test aliasing the second argument and the receiver. |
| v1.Set(y) |
| if out := f(v1, x, v1); out != v1 || !equal(v1, v) { |
| t.Logf("f(v, x, y) != f(y, x, y)") |
| return false |
| } |
| |
| // Calculate a reference f(y, y) without aliasing. |
| // We use y because it's the one that commonly has restrictions |
| // like being prime or non-zero. |
| v1.Set(v) |
| y2 := new(big.Int).Set(y) |
| if out := f(v, y, y2); out == nil { |
| return equal(y, y1) && equal(y2, y1) && equal(v, v1) |
| } else if out != v { |
| return false |
| } |
| |
| // Test aliasing the two arguments. |
| if out := f(v1, y, y); out != v1 || !equal(v1, v) { |
| t.Logf("f(v, y1, y2) != f(v, y, y)") |
| return false |
| } |
| // Test aliasing the two arguments and the receiver. |
| v1.Set(y) |
| if out := f(v1, v1, v1); out != v1 || !equal(v1, v) { |
| t.Logf("f(v, y1, y2) != f(y, y, y)") |
| return false |
| } |
| |
| // Ensure the arguments were not modified. |
| return equal(x, x1) && equal(y, y1) |
| } |
| |
| func TestAliasing(t *testing.T) { |
| for name, f := range map[string]interface{}{ |
| "Abs": func(v, x bigInt) bool { |
| return checkAliasingOneArg(t, (*big.Int).Abs, v.Int, x.Int) |
| }, |
| "Add": func(v, x, y bigInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Add, v.Int, x.Int, y.Int) |
| }, |
| "And": func(v, x, y bigInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).And, v.Int, x.Int, y.Int) |
| }, |
| "AndNot": func(v, x, y bigInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).AndNot, v.Int, x.Int, y.Int) |
| }, |
| "Div": func(v, x bigInt, y notZeroInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Div, v.Int, x.Int, y.Int) |
| }, |
| "Exp-XY": func(v, x, y bigInt, z notZeroInt) bool { |
| return checkAliasingTwoArgs(t, func(v, x, y *big.Int) *big.Int { |
| return v.Exp(x, y, z.Int) |
| }, v.Int, x.Int, y.Int) |
| }, |
| "Exp-XZ": func(v, x, y bigInt, z notZeroInt) bool { |
| return checkAliasingTwoArgs(t, func(v, x, z *big.Int) *big.Int { |
| return v.Exp(x, y.Int, z) |
| }, v.Int, x.Int, z.Int) |
| }, |
| "Exp-YZ": func(v, x, y bigInt, z notZeroInt) bool { |
| return checkAliasingTwoArgs(t, func(v, y, z *big.Int) *big.Int { |
| return v.Exp(x.Int, y, z) |
| }, v.Int, y.Int, z.Int) |
| }, |
| "GCD": func(v, x, y bigInt) bool { |
| return checkAliasingTwoArgs(t, func(v, x, y *big.Int) *big.Int { |
| return v.GCD(nil, nil, x, y) |
| }, v.Int, x.Int, y.Int) |
| }, |
| "GCD-X": func(v, x, y bigInt) bool { |
| a, b := new(big.Int), new(big.Int) |
| return checkAliasingTwoArgs(t, func(v, x, y *big.Int) *big.Int { |
| a.GCD(v, b, x, y) |
| return v |
| }, v.Int, x.Int, y.Int) |
| }, |
| "GCD-Y": func(v, x, y bigInt) bool { |
| a, b := new(big.Int), new(big.Int) |
| return checkAliasingTwoArgs(t, func(v, x, y *big.Int) *big.Int { |
| a.GCD(b, v, x, y) |
| return v |
| }, v.Int, x.Int, y.Int) |
| }, |
| "Lsh": func(v, x bigInt, n smallUint) bool { |
| return checkAliasingOneArg(t, func(v, x *big.Int) *big.Int { |
| return v.Lsh(x, n.uint) |
| }, v.Int, x.Int) |
| }, |
| "Mod": func(v, x bigInt, y notZeroInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Mod, v.Int, x.Int, y.Int) |
| }, |
| "ModInverse": func(v, x bigInt, y notZeroInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).ModInverse, v.Int, x.Int, y.Int) |
| }, |
| "ModSqrt": func(v, x bigInt, p prime) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).ModSqrt, v.Int, x.Int, p.Int) |
| }, |
| "Mul": func(v, x, y bigInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Mul, v.Int, x.Int, y.Int) |
| }, |
| "Neg": func(v, x bigInt) bool { |
| return checkAliasingOneArg(t, (*big.Int).Neg, v.Int, x.Int) |
| }, |
| "Not": func(v, x bigInt) bool { |
| return checkAliasingOneArg(t, (*big.Int).Not, v.Int, x.Int) |
| }, |
| "Or": func(v, x, y bigInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Or, v.Int, x.Int, y.Int) |
| }, |
| "Quo": func(v, x bigInt, y notZeroInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Quo, v.Int, x.Int, y.Int) |
| }, |
| "Rand": func(v, x bigInt, seed int64) bool { |
| return checkAliasingOneArg(t, func(v, x *big.Int) *big.Int { |
| rnd := rand.New(rand.NewSource(seed)) |
| return v.Rand(rnd, x) |
| }, v.Int, x.Int) |
| }, |
| "Rem": func(v, x bigInt, y notZeroInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Rem, v.Int, x.Int, y.Int) |
| }, |
| "Rsh": func(v, x bigInt, n smallUint) bool { |
| return checkAliasingOneArg(t, func(v, x *big.Int) *big.Int { |
| return v.Rsh(x, n.uint) |
| }, v.Int, x.Int) |
| }, |
| "Set": func(v, x bigInt) bool { |
| return checkAliasingOneArg(t, (*big.Int).Set, v.Int, x.Int) |
| }, |
| "SetBit": func(v, x bigInt, i smallUint, b zeroOrOne) bool { |
| return checkAliasingOneArg(t, func(v, x *big.Int) *big.Int { |
| return v.SetBit(x, int(i.uint), b.uint) |
| }, v.Int, x.Int) |
| }, |
| "Sqrt": func(v bigInt, x positiveInt) bool { |
| return checkAliasingOneArg(t, (*big.Int).Sqrt, v.Int, x.Int) |
| }, |
| "Sub": func(v, x, y bigInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Sub, v.Int, x.Int, y.Int) |
| }, |
| "Xor": func(v, x, y bigInt) bool { |
| return checkAliasingTwoArgs(t, (*big.Int).Xor, v.Int, x.Int, y.Int) |
| }, |
| } { |
| t.Run(name, func(t *testing.T) { |
| scale := 1.0 |
| switch name { |
| case "ModInverse", "GCD-Y", "GCD-X": |
| scale /= 5 |
| case "Rand": |
| scale /= 10 |
| case "Exp-XZ", "Exp-XY", "Exp-YZ": |
| scale /= 50 |
| case "ModSqrt": |
| scale /= 500 |
| } |
| if err := quick.Check(f, &quick.Config{ |
| MaxCountScale: scale, |
| }); err != nil { |
| t.Error(err) |
| } |
| }) |
| } |
| |
| t.Run("Issue72043a", func(t *testing.T) { |
| v := new(big.Int).SetBytes([]byte{0x4b, 0xd2, 0x7a, 0x6c, 0xb3, 0x16, 0x5a, 0xf3, 0xa0, 0x45, 0x2b, 0xbe, 0x38, 0xba, 0x18, 0xb8, 0x70, 0xbb, 0xde, 0xd2, 0x20, 0xe9, 0xb9, 0x9d, 0x1d, 0xc6, 0x3e, 0xa, 0xa5, 0x60, 0x11, 0xcc, 0xb8, 0xff, 0x8e, 0x62}) |
| x := new(big.Int).SetBytes([]byte{0xb, 0x40, 0x70, 0x8b, 0x64, 0x78, 0x29, 0x9e, 0xd0}) |
| y := new(big.Int).SetBytes([]byte{0x1}) |
| z := new(big.Int).SetBytes([]byte{0xe, 0x91, 0x4d, 0xaa, 0x69, 0x60, 0x51, 0x42, 0x9, 0xa1, 0xf6, 0xfa, 0x5, 0x97, 0x1c, 0x5e, 0x18, 0xaa, 0x91, 0x87, 0x1f, 0xe4, 0x70, 0x84, 0x54, 0x97, 0x3a, 0xc9, 0xe1, 0x92, 0xd4, 0xf3, 0xdf, 0x79, 0x90, 0x18, 0xdd, 0xdf, 0x19, 0x44, 0xf3, 0xf, 0x9d, 0xa6, 0xf, 0xd9}) |
| v.Exp(x, y, z) |
| }) |
| |
| t.Run("Issue72043b", func(t *testing.T) { |
| v := new(big.Int).SetBytes([]byte{0x1, 0x6b, 0x8a, 0x26, 0x2, 0x1d, 0x3b, 0x4, 0x8d, 0x81, 0x85, 0xdb, 0x78, 0x4e, 0x81, 0xb7, 0xa7, 0xc0, 0x6e, 0xe7, 0xa0, 0xa, 0x54, 0x39, 0x3e, 0xa8, 0xb1, 0xe0, 0x0, 0xdb, 0x5a, 0x45, 0xde, 0xbf, 0xe2, 0xc8, 0x4d, 0x2b, 0x80, 0x65, 0x73, 0x5d, 0x6d, 0x65, 0x40, 0x50, 0xd4, 0x8}) |
| x := new(big.Int).SetBytes([]byte{0x7, 0xd6, 0x79, 0xc5, 0x30, 0xc2, 0x1f, 0x39, 0x5e, 0x3d, 0xd2, 0x52, 0xc6, 0xfb, 0xa7, 0xe2, 0x8a, 0x37, 0xdd}) |
| y := new(big.Int).SetBytes([]byte{0x1}) |
| z := new(big.Int).SetBytes([]byte{0x1c, 0x44, 0xba, 0x75, 0xfa, 0xe5, 0x3a, 0x56, 0xc0, 0x94, 0xa, 0x1e, 0x8f, 0xbd, 0xad, 0xdb, 0x17, 0xb8, 0x2b, 0x46, 0xf8, 0x69, 0xc1, 0x54, 0x25, 0x68, 0x53, 0xb5, 0xd5, 0x89, 0x6c, 0x16, 0xef, 0xf2, 0x83, 0x3e, 0x55, 0xa7, 0x54, 0x32, 0xbd, 0xa7, 0x70, 0x13, 0xa4, 0xfa}) |
| v.Exp(x, y, z) |
| }) |
| |
| t.Run("Issue72043c", func(t *testing.T) { |
| v := new(big.Int).SetBytes([]byte{0x2, 0x2a, 0xfc, 0x65, 0xc2, 0x66, 0xb1, 0x63, 0x56, 0xaf, 0x5c, 0x6, 0x4a, 0x19, 0x82, 0x6b, 0xaa, 0x90, 0x57, 0xd9, 0xd0, 0x3e, 0x83, 0xc8, 0x2a, 0x85, 0xe0}) |
| x := new(big.Int).SetBytes([]byte{0x8, 0x6f, 0xc5, 0x74, 0x83, 0x56, 0xa5, 0x6e, 0xfe, 0x7b, 0x32, 0xfb, 0x69, 0x4, 0x3, 0x51, 0xf5, 0x2c, 0x41, 0x7, 0xf7, 0xbb, 0x89, 0x8e}) |
| y := new(big.Int).SetBytes([]byte{0x1}) |
| z := new(big.Int).SetBytes([]byte{0x34, 0xe1, 0x5f, 0xd0, 0xa7, 0xf8, 0x34, 0x7c, 0x3c, 0x63, 0x82, 0x1e, 0xc3, 0x84, 0x9f, 0xa, 0x70, 0x22, 0xd3, 0xc8, 0x24, 0x64, 0x2b, 0xd7, 0x59, 0x20, 0xf2, 0xdd, 0xb5, 0xb2, 0xfa, 0x11, 0x2e, 0x98, 0x95}) |
| v.Exp(x, y, z) |
| }) |
| } |