crypto: add btcec fallback for sign/recover without cgo (#3680)

* vendor: add github.com/btcsuite/btcd/btcec

* crypto: add btcec fallback for sign/recover without cgo

This commit adds a non-cgo fallback implementation of secp256k1
operations.

* crypto, core/vm: remove wrappers for sha256, ripemd160

1 files changed, 16 insertions, 10 deletions

diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index 593b6ca55..1447c2cad 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -17,11 +17,14 @@
 package vm
 
 import (
+	"crypto/sha256"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/ethereum/go-ethereum/params"
+	"golang.org/x/crypto/ripemd160"
 )
 
 // Precompiled contract is the basic interface for native Go contracts. The implementation
@@ -35,8 +38,8 @@ type PrecompiledContract interface {
 // Precompiled contains the default set of ethereum contracts
 var PrecompiledContracts = map[common.Address]PrecompiledContract{
 	common.BytesToAddress([]byte{1}): &ecrecover{},
-	common.BytesToAddress([]byte{2}): &sha256{},
-	common.BytesToAddress([]byte{3}): &ripemd160{},
+	common.BytesToAddress([]byte{2}): &sha256hash{},
+	common.BytesToAddress([]byte{3}): &ripemd160hash{},
 	common.BytesToAddress([]byte{4}): &dataCopy{},
 }
 
@@ -88,31 +91,34 @@ func (c *ecrecover) Run(in []byte) []byte {
 }
 
 // SHA256 implemented as a native contract
-type sha256 struct{}
+type sha256hash struct{}
 
 // RequiredGas returns the gas required to execute the pre-compiled contract.
 //
 // This method does not require any overflow checking as the input size gas costs
 // required for anything significant is so high it's impossible to pay for.
-func (c *sha256) RequiredGas(inputSize int) uint64 {
+func (c *sha256hash) RequiredGas(inputSize int) uint64 {
 	return uint64(inputSize+31)/32*params.Sha256WordGas + params.Sha256Gas
 }
-func (c *sha256) Run(in []byte) []byte {
-	return crypto.Sha256(in)
+func (c *sha256hash) Run(in []byte) []byte {
+	h := sha256.Sum256(in)
+	return h[:]
 }
 
 // RIPMED160 implemented as a native contract
-type ripemd160 struct{}
+type ripemd160hash struct{}
 
 // RequiredGas returns the gas required to execute the pre-compiled contract.
 //
 // This method does not require any overflow checking as the input size gas costs
 // required for anything significant is so high it's impossible to pay for.
-func (c *ripemd160) RequiredGas(inputSize int) uint64 {
+func (c *ripemd160hash) RequiredGas(inputSize int) uint64 {
 	return uint64(inputSize+31)/32*params.Ripemd160WordGas + params.Ripemd160Gas
 }
-func (c *ripemd160) Run(in []byte) []byte {
-	return common.LeftPadBytes(crypto.Ripemd160(in), 32)
+func (c *ripemd160hash) Run(in []byte) []byte {
+	ripemd := ripemd160.New()
+	ripemd.Write(in)
+	return common.LeftPadBytes(ripemd.Sum(nil), 32)
 }
 
 // data copy implemented as a native contract