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sm2: use golang 1.19 style marshal/unmarshal

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Sun Yimin 2022-08-18 09:12:00 +08:00 committed by GitHub
parent 37f3e129da
commit ae12f04c14
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3 changed files with 37 additions and 37 deletions
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4
sm2/sm2.go
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@ -136,7 +136,7 @@ func bytes2Point(curve elliptic.Curve, bytes []byte) (*big.Int, *big.Int, int, e
data := make([]byte, 1+byteLen*2)
data[0] = uncompressed
copy(data[1:], bytes[1:1+byteLen*2])
x, y := elliptic.Unmarshal(curve, data)
x, y := sm2ec.Unmarshal(curve, data)
if x == nil || y == nil {
return nil, nil, 0, fmt.Errorf("sm2: point is not on curve %s", curve.Params().Name)
}
@ -148,7 +148,7 @@ func bytes2Point(curve elliptic.Curve, bytes []byte) (*big.Int, *big.Int, int, e
// Make sure it's NIST curve or SM2 P-256 curve
if strings.HasPrefix(curve.Params().Name, "P-") || strings.EqualFold(curve.Params().Name, sm2ec.P256().Params().Name) {
// y² = x³ - 3x + b, prime curves
x, y := elliptic.UnmarshalCompressed(curve, bytes[:1+byteLen])
x, y := sm2ec.UnmarshalCompressed(curve, bytes[:1+byteLen])
if x == nil || y == nil {
return nil, nil, 0, fmt.Errorf("sm2: point is not on curve %s", curve.Params().Name)
}

26
sm2/sm2ec/elliptic.go
View File

@ -34,3 +34,29 @@ func P256() elliptic.Curve {
initonce.Do(initAll)
return sm2p256
}
// Since golang 1.19
// unmarshaler is implemented by curves with their own constant-time Unmarshal.
// There isn't an equivalent interface for Marshal/MarshalCompressed because
// that doesn't involve any mathematical operations, only FillBytes and Bit.
type unmarshaler interface {
Unmarshal([]byte) (x, y *big.Int)
UnmarshalCompressed([]byte) (x, y *big.Int)
}
func Unmarshal(curve elliptic.Curve, data []byte) (x, y *big.Int) {
if c, ok := curve.(unmarshaler); ok {
return c.Unmarshal(data)
}
return elliptic.Unmarshal(curve, data)
}
// UnmarshalCompressed converts a point, serialized by MarshalCompressed, into
// an x, y pair. It is an error if the point is not in compressed form, is not
// on the curve, or is the point at infinity. On error, x = nil.
func UnmarshalCompressed(curve elliptic.Curve, data []byte) (x, y *big.Int) {
if c, ok := curve.(unmarshaler); ok {
return c.UnmarshalCompressed(data)
}
return elliptic.UnmarshalCompressed(curve, data)
}

44
sm2/sm2ec/elliptic_test.go
View File

@ -11,32 +11,6 @@ import (
var _ = elliptic.P256() // force NIST P curves init, avoid panic when we invoke generic implementation's method
// unmarshaler is implemented by curves with their own constant-time Unmarshal.
// Since golang 1.19
// There isn't an equivalent interface for Marshal/MarshalCompressed because
// that doesn't involve any mathematical operations, only FillBytes and Bit.
type unmarshaler interface {
Unmarshal([]byte) (x, y *big.Int)
UnmarshalCompressed([]byte) (x, y *big.Int)
}
func unmarshal(curve elliptic.Curve, data []byte) (x, y *big.Int) {
if c, ok := curve.(unmarshaler); ok {
return c.Unmarshal(data)
}
return elliptic.Unmarshal(curve, data)
}
// UnmarshalCompressed converts a point, serialized by MarshalCompressed, into
// an x, y pair. It is an error if the point is not in compressed form, is not
// on the curve, or is the point at infinity. On error, x = nil.
func unmarshalCompressed(curve elliptic.Curve, data []byte) (x, y *big.Int) {
if c, ok := curve.(unmarshaler); ok {
return c.UnmarshalCompressed(data)
}
return elliptic.UnmarshalCompressed(curve, data)
}
// genericParamsForCurve returns the dereferenced CurveParams for
// the specified curve. This is used to avoid the logic for
// upgrading a curve to its specific implementation, forcing
@ -87,7 +61,7 @@ func TestOffCurve(t *testing.T) {
x.FillBytes(b[1 : 1+byteLen])
y.FillBytes(b[1+byteLen : 1+2*byteLen])
x1, y1 := unmarshal(curve, b)
x1, y1 := Unmarshal(curve, b)
if x1 != nil || y1 != nil {
t.Errorf("unmarshaling a point not on the curve succeeded")
}
@ -152,18 +126,18 @@ func testInfinity(t *testing.T, curve elliptic.Curve) {
t.Errorf("IsOnCurve(∞) == true")
}
if xx, yy := unmarshal(curve, elliptic.Marshal(curve, x0, y0)); xx != nil || yy != nil {
if xx, yy := Unmarshal(curve, elliptic.Marshal(curve, x0, y0)); xx != nil || yy != nil {
t.Errorf("Unmarshal(Marshal(∞)) did not return an error")
}
// We don't test UnmarshalCompressed(MarshalCompressed(∞)) because there are
// two valid points with x = 0.
if xx, yy := unmarshal(curve, []byte{0x00}); xx != nil || yy != nil {
if xx, yy := Unmarshal(curve, []byte{0x00}); xx != nil || yy != nil {
t.Errorf("Unmarshal(∞) did not return an error")
}
byteLen := (curve.Params().BitSize + 7) / 8
buf := make([]byte, byteLen*2+1)
buf[0] = 4 // Uncompressed format.
if xx, yy := unmarshal(curve, buf); xx != nil || yy != nil {
if xx, yy := Unmarshal(curve, buf); xx != nil || yy != nil {
t.Errorf("Unmarshal((0,0)) did not return an error")
}
}
@ -175,7 +149,7 @@ func TestMarshal(t *testing.T) {
t.Fatal(err)
}
serialized := elliptic.Marshal(curve, x, y)
xx, yy := unmarshal(curve, serialized)
xx, yy := Unmarshal(curve, serialized)
if xx == nil {
t.Fatal("failed to unmarshal")
}
@ -256,7 +230,7 @@ func TestMarshalCompressed(t *testing.T) {
t.Run("Invalid", func(t *testing.T) {
data, _ := hex.DecodeString("02fd4bf61763b46581fd9174d623516cf3c81edd40e29ffa2777fb6cb0ae3ce535")
X, Y := unmarshalCompressed(P256(), data)
X, Y := UnmarshalCompressed(P256(), data)
if X != nil || Y != nil {
t.Error("expected an error for invalid encoding")
}
@ -284,7 +258,7 @@ func testMarshalCompressed(t *testing.T, curve elliptic.Curve, x, y *big.Int, wa
t.Errorf("got unexpected MarshalCompressed result: got %x, want %x", got, want)
}
X, Y := unmarshalCompressed(curve, got)
X, Y := UnmarshalCompressed(curve, got)
if X == nil || Y == nil {
t.Fatalf("UnmarshalCompressed failed unexpectedly")
}
@ -354,7 +328,7 @@ func BenchmarkMarshalUnmarshal(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
buf := elliptic.Marshal(curve, x, y)
xx, yy := unmarshal(curve, buf)
xx, yy := Unmarshal(curve, buf)
if xx.Cmp(x) != 0 || yy.Cmp(y) != 0 {
b.Error("Unmarshal output different from Marshal input")
}
@ -364,7 +338,7 @@ func BenchmarkMarshalUnmarshal(b *testing.B) {
b.ReportAllocs()
for i := 0; i < b.N; i++ {
buf := elliptic.MarshalCompressed(curve, x, y)
xx, yy := unmarshalCompressed(curve, buf)
xx, yy := UnmarshalCompressed(curve, buf)
if xx.Cmp(x) != 0 || yy.Cmp(y) != 0 {
b.Error("Unmarshal output different from Marshal input")
}