Merge pull request #32 from libp2p/bug/key-equality

Replace bytes.Equal -> subtle.ConstantTimeCompare

crypto/ecdsa.go

@@ -115,7 +115,7 @@ func (ePriv *ECDSAPrivateKey) Raw() ([]byte, error) {
 	return x509.MarshalECPrivateKey(ePriv.priv)
 }
 
-// Equals compares to private keys
+// Equals compares two private keys
 func (ePriv *ECDSAPrivateKey) Equals(o Key) bool {
 	oPriv, ok := o.(*ECDSAPrivateKey)
 	if !ok {

crypto/ed25519.go

@@ -2,6 +2,7 @@ package crypto
 
 import (
 	"bytes"
+	"crypto/subtle"
 	"errors"
 	"fmt"
 	"io"
@@ -70,7 +71,7 @@ func (k *Ed25519PrivateKey) Equals(o Key) bool {
 		return false
 	}
 
-	return bytes.Equal(k.k, edk.k)
+	return subtle.ConstantTimeCompare(k.k, edk.k) == 1
 }
 
 // GetPublic returns an ed25519 public key from a private key.

crypto/key.go

@@ -4,12 +4,12 @@
 package crypto
 
 import (
-	"bytes"
 	"crypto/elliptic"
 	"crypto/hmac"
 	"crypto/rand"
 	"crypto/sha1"
 	"crypto/sha512"
+	"crypto/subtle"
 	"encoding/base64"
 	"errors"
 	"fmt"
@@ -364,5 +364,5 @@ func KeyEqual(k1, k2 Key) bool {
 
 	b1, err1 := k1.Bytes()
 	b2, err2 := k2.Bytes()
-	return bytes.Equal(b1, b2) && err1 == err2
+	return subtle.ConstantTimeCompare(b1, b2) == 1 && err1 == err2
 }