2 files changed, 145 insertions, 0 deletions

diff --git a/src/crypto/ecdsa/boring.go b/src/crypto/ecdsa/boring.go
new file mode 100644
index 0000000000..fa15ecb850
--- /dev/null
+++ b/src/crypto/ecdsa/boring.go
@@ -0,0 +1,100 @@
+// Copyright 2017 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 ecdsa
+
+import (
+	"crypto/internal/boring"
+	"math/big"
+	"sync/atomic"
+	"unsafe"
+)
+
+// Cached conversions from Go PublicKey/PrivateKey to BoringCrypto.
+//
+// A new 'boring atomic.Value' field in both PublicKey and PrivateKey
+// serves as a cache for the most recent conversion. The cache is an
+// atomic.Value because code might reasonably set up a key and then
+// (thinking it immutable) use it from multiple goroutines simultaneously.
+// The first operation initializes the cache; if there are multiple simultaneous
+// first operations, they will do redundant work but not step on each other.
+//
+// We could just assume that once used in a Sign or Verify operation,
+// a particular key is never again modified, but that has not been a
+// stated assumption before. Just in case there is any existing code that
+// does modify the key between operations, we save the original values
+// alongside the cached BoringCrypto key and check that the real key
+// still matches before using the cached key. The theory is that the real
+// operations are significantly more expensive than the comparison.
+
+type boringPub struct {
+	key  *boring.PublicKeyECDSA
+	orig PublicKey
+}
+
+func boringPublicKey(pub *PublicKey) (*boring.PublicKeyECDSA, error) {
+	b := (*boringPub)(atomic.LoadPointer(&pub.boring))
+	if b != nil && publicKeyEqual(&b.orig, pub) {
+		return b.key, nil
+	}
+
+	b = new(boringPub)
+	b.orig = copyPublicKey(pub)
+	key, err := boring.NewPublicKeyECDSA(b.orig.Curve.Params().Name, b.orig.X, b.orig.Y)
+	if err != nil {
+		return nil, err
+	}
+	b.key = key
+	atomic.StorePointer(&pub.boring, unsafe.Pointer(b))
+	return key, nil
+}
+
+type boringPriv struct {
+	key  *boring.PrivateKeyECDSA
+	orig PrivateKey
+}
+
+func boringPrivateKey(priv *PrivateKey) (*boring.PrivateKeyECDSA, error) {
+	b := (*boringPriv)(atomic.LoadPointer(&priv.boring))
+	if b != nil && privateKeyEqual(&b.orig, priv) {
+		return b.key, nil
+	}
+
+	b = new(boringPriv)
+	b.orig = copyPrivateKey(priv)
+	key, err := boring.NewPrivateKeyECDSA(b.orig.Curve.Params().Name, b.orig.X, b.orig.Y, b.orig.D)
+	if err != nil {
+		return nil, err
+	}
+	b.key = key
+	atomic.StorePointer(&priv.boring, unsafe.Pointer(b))
+	return key, nil
+}
+
+func publicKeyEqual(k1, k2 *PublicKey) bool {
+	return k1.X != nil &&
+		k1.Curve.Params() == k2.Curve.Params() &&
+		k1.X.Cmp(k2.X) == 0 &&
+		k1.Y.Cmp(k2.Y) == 0
+}
+
+func privateKeyEqual(k1, k2 *PrivateKey) bool {
+	return publicKeyEqual(&k1.PublicKey, &k2.PublicKey) &&
+		k1.D.Cmp(k2.D) == 0
+}
+
+func copyPublicKey(k *PublicKey) PublicKey {
+	return PublicKey{
+		Curve: k.Curve,
+		X:     new(big.Int).Set(k.X),
+		Y:     new(big.Int).Set(k.Y),
+	}
+}
+
+func copyPrivateKey(k *PrivateKey) PrivateKey {
+	return PrivateKey{
+		PublicKey: copyPublicKey(&k.PublicKey),
+		D:         new(big.Int).Set(k.D),
+	}
+}
diff --git a/src/crypto/ecdsa/ecdsa.go b/src/crypto/ecdsa/ecdsa.go
index ccce873859..04738cdbd7 100644
--- a/src/crypto/ecdsa/ecdsa.go
+++ b/src/crypto/ecdsa/ecdsa.go
@@ -41,6 +41,11 @@ import (
 	"golang.org/x/crypto/cryptobyte/asn1"
 )
 
+import (
+	"crypto/internal/boring"
+	"unsafe"
+)
+
 // A invertible implements fast inverse mod Curve.Params().N
 type invertible interface {
 	// Inverse returns the inverse of k in GF(P)
@@ -60,6 +65,8 @@ const (
 type PublicKey struct {
 	elliptic.Curve
 	X, Y *big.Int
+
+	boring unsafe.Pointer
 }
 
 // Any methods implemented on PublicKey might need to also be implemented on
@@ -87,6 +94,8 @@ func (pub *PublicKey) Equal(x crypto.PublicKey) bool {
 type PrivateKey struct {
 	PublicKey
 	D *big.Int
+
+	boring unsafe.Pointer
 }
 
 // Public returns the public key corresponding to priv.
@@ -113,6 +122,15 @@ func (priv *PrivateKey) Equal(x crypto.PrivateKey) bool {
 // where the private part is kept in, for example, a hardware module. Common
 // uses should use the Sign function in this package directly.
 func (priv *PrivateKey) Sign(rand io.Reader, digest []byte, opts crypto.SignerOpts) ([]byte, error) {
+	if boring.Enabled && rand == boring.RandReader {
+		b, err := boringPrivateKey(priv)
+		if err != nil {
+			return nil, err
+		}
+		return boring.SignMarshalECDSA(b, digest)
+	}
+	boring.UnreachableExceptTests()
+
 	r, s, err := Sign(rand, priv, digest)
 	if err != nil {
 		return nil, err
@@ -147,6 +165,15 @@ func randFieldElement(c elliptic.Curve, rand io.Reader) (k *big.Int, err error)
 
 // GenerateKey generates a public and private key pair.
 func GenerateKey(c elliptic.Curve, rand io.Reader) (*PrivateKey, error) {
+	if boring.Enabled && rand == boring.RandReader {
+		x, y, d, err := boring.GenerateKeyECDSA(c.Params().Name)
+		if err != nil {
+			return nil, err
+		}
+		return &PrivateKey{PublicKey: PublicKey{Curve: c, X: x, Y: y}, D: d}, nil
+	}
+	boring.UnreachableExceptTests()
+
 	k, err := randFieldElement(c, rand)
 	if err != nil {
 		return nil, err
@@ -200,6 +227,15 @@ var errZeroParam = errors.New("zero parameter")
 func Sign(rand io.Reader, priv *PrivateKey, hash []byte) (r, s *big.Int, err error) {
 	randutil.MaybeReadByte(rand)
 
+	if boring.Enabled && rand == boring.RandReader {
+		b, err := boringPrivateKey(priv)
+		if err != nil {
+			return nil, nil, err
+		}
+		return boring.SignECDSA(b, hash)
+	}
+	boring.UnreachableExceptTests()
+
 	// Get min(log2(q) / 2, 256) bits of entropy from rand.
 	entropylen := (priv.Curve.Params().BitSize + 7) / 16
 	if entropylen > 32 {
@@ -289,6 +325,15 @@ func SignASN1(rand io.Reader, priv *PrivateKey, hash []byte) ([]byte, error) {
 // Verify verifies the signature in r, s of hash using the public key, pub. Its
 // return value records whether the signature is valid.
 func Verify(pub *PublicKey, hash []byte, r, s *big.Int) bool {
+	if boring.Enabled {
+		b, err := boringPublicKey(pub)
+		if err != nil {
+			return false
+		}
+		return boring.VerifyECDSA(b, hash, r, s)
+	}
+	boring.UnreachableExceptTests()
+
 	// See [NSA] 3.4.2
 	c := pub.Curve
 	N := c.Params().N