plugeth/core/vm/contracts.go
2015-06-09 16:03:05 +02:00

103 lines
2.7 KiB
Go

package vm
import (
"math/big"
"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"
)
type Address interface {
Call(in []byte) []byte
}
type PrecompiledAccount struct {
Gas func(l int) *big.Int
fn func(in []byte) []byte
}
func (self PrecompiledAccount) Call(in []byte) []byte {
return self.fn(in)
}
var Precompiled = PrecompiledContracts()
// XXX Could set directly. Testing requires resetting and setting of pre compiled contracts.
func PrecompiledContracts() map[string]*PrecompiledAccount {
return map[string]*PrecompiledAccount{
// ECRECOVER
string(common.LeftPadBytes([]byte{1}, 20)): &PrecompiledAccount{func(l int) *big.Int {
return params.EcrecoverGas
}, ecrecoverFunc},
// SHA256
string(common.LeftPadBytes([]byte{2}, 20)): &PrecompiledAccount{func(l int) *big.Int {
n := big.NewInt(int64(l+31) / 32)
n.Mul(n, params.Sha256WordGas)
return n.Add(n, params.Sha256Gas)
}, sha256Func},
// RIPEMD160
string(common.LeftPadBytes([]byte{3}, 20)): &PrecompiledAccount{func(l int) *big.Int {
n := big.NewInt(int64(l+31) / 32)
n.Mul(n, params.Ripemd160WordGas)
return n.Add(n, params.Ripemd160Gas)
}, ripemd160Func},
string(common.LeftPadBytes([]byte{4}, 20)): &PrecompiledAccount{func(l int) *big.Int {
n := big.NewInt(int64(l+31) / 32)
n.Mul(n, params.IdentityWordGas)
return n.Add(n, params.IdentityGas)
}, memCpy},
}
}
func sha256Func(in []byte) []byte {
return crypto.Sha256(in)
}
func ripemd160Func(in []byte) []byte {
return common.LeftPadBytes(crypto.Ripemd160(in), 32)
}
const ecRecoverInputLength = 128
func ecrecoverFunc(in []byte) []byte {
in = common.RightPadBytes(in, 128)
// "in" is (hash, v, r, s), each 32 bytes
// but for ecrecover we want (r, s, v)
r := common.BytesToBig(in[64:96])
s := common.BytesToBig(in[96:128])
// Treat V as a 256bit integer
vbig := common.Bytes2Big(in[32:64])
v := byte(vbig.Uint64())
if !crypto.ValidateSignatureValues(v, r, s) {
glog.V(logger.Error).Infof("EC RECOVER FAIL: v, r or s value invalid")
return nil
}
// v needs to be at the end and normalized for libsecp256k1
vbignormal := new(big.Int).Sub(vbig, big.NewInt(27))
vnormal := byte(vbignormal.Uint64())
rsv := append(in[64:128], vnormal)
pubKey, err := crypto.Ecrecover(in[:32], rsv)
// make sure the public key is a valid one
if err != nil {
glog.V(logger.Error).Infof("EC RECOVER FAIL: ", err)
return nil
}
// the first byte of pubkey is bitcoin heritage
return common.LeftPadBytes(crypto.Sha3(pubKey[1:])[12:], 32)
}
func memCpy(in []byte) []byte {
return in
}