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