core: add Metropolis pre-compiles (EIP 197, 198 and 213)

3 files changed, 242 insertions, 2 deletions

diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index 43b60ba77..407f198f0 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -22,7 +22,9 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/crypto/bn256"
 	"github.com/ethereum/go-ethereum/params"
 	"golang.org/x/crypto/ripemd160"
 )
@@ -45,6 +47,19 @@ var PrecompiledContracts = map[common.Address]PrecompiledContract{
 	common.BytesToAddress([]byte{4}): &dataCopy{},
 }
 
+// PrecompiledContractsMetropolis contains the default set of ethereum contracts
+// for metropolis hardfork
+var PrecompiledContractsMetropolis = map[common.Address]PrecompiledContract{
+	common.BytesToAddress([]byte{1}): &ecrecover{},
+	common.BytesToAddress([]byte{2}): &sha256hash{},
+	common.BytesToAddress([]byte{3}): &ripemd160hash{},
+	common.BytesToAddress([]byte{4}): &dataCopy{},
+	common.BytesToAddress([]byte{5}): &bigModexp{},
+	common.BytesToAddress([]byte{6}): &bn256Add{},
+	common.BytesToAddress([]byte{7}): &bn256ScalarMul{},
+	common.BytesToAddress([]byte{8}): &pairing{},
+}
+
 // RunPrecompile runs and evaluate the output of a precompiled contract defined in contracts.go
 func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) {
 	gas := p.RequiredGas(input)
@@ -132,3 +147,190 @@ func (c *dataCopy) RequiredGas(input []byte) uint64 {
 func (c *dataCopy) Run(in []byte) ([]byte, error) {
 	return in, nil
 }
+
+// bigModexp implements a native big integer exponential modular operation.
+type bigModexp 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 *bigModexp) RequiredGas(input []byte) uint64 {
+	// TODO reword required gas to have error reporting and convert arithmetic
+	// to uint64.
+	if len(input) < 3*32 {
+		input = append(input, make([]byte, 3*32-len(input))...)
+	}
+	var (
+		baseLen = new(big.Int).SetBytes(input[:31])
+		expLen  = math.BigMax(new(big.Int).SetBytes(input[32:64]), big.NewInt(1))
+		modLen  = new(big.Int).SetBytes(input[65:97])
+	)
+	x := new(big.Int).Set(math.BigMax(baseLen, modLen))
+	x.Mul(x, x)
+	x.Mul(x, expLen)
+	x.Div(x, new(big.Int).SetUint64(params.QuadCoeffDiv))
+
+	return x.Uint64()
+}
+
+func (c *bigModexp) Run(input []byte) ([]byte, error) {
+	if len(input) < 3*32 {
+		input = append(input, make([]byte, 3*32-len(input))...)
+	}
+	// why 32-byte? These values won't fit anyway
+	var (
+		baseLen = new(big.Int).SetBytes(input[:32]).Uint64()
+		expLen  = new(big.Int).SetBytes(input[32:64]).Uint64()
+		modLen  = new(big.Int).SetBytes(input[64:96]).Uint64()
+	)
+
+	input = input[96:]
+	if uint64(len(input)) < baseLen {
+		input = append(input, make([]byte, baseLen-uint64(len(input)))...)
+	}
+	base := new(big.Int).SetBytes(input[:baseLen])
+
+	input = input[baseLen:]
+	if uint64(len(input)) < expLen {
+		input = append(input, make([]byte, expLen-uint64(len(input)))...)
+	}
+	exp := new(big.Int).SetBytes(input[:expLen])
+
+	input = input[expLen:]
+	if uint64(len(input)) < modLen {
+		input = append(input, make([]byte, modLen-uint64(len(input)))...)
+	}
+	mod := new(big.Int).SetBytes(input[:modLen])
+
+	return common.LeftPadBytes(base.Exp(base, exp, mod).Bytes(), len(input[:modLen])), nil
+}
+
+type bn256Add 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 *bn256Add) RequiredGas(input []byte) uint64 {
+	return 0 // TODO
+}
+
+func (c *bn256Add) Run(in []byte) ([]byte, error) {
+	in = common.RightPadBytes(in, 128)
+
+	x, onCurve := new(bn256.G1).Unmarshal(in[:64])
+	if !onCurve {
+		return nil, errNotOnCurve
+	}
+	gx, gy, _, _ := x.CurvePoints()
+	if gx.Cmp(bn256.P) >= 0 || gy.Cmp(bn256.P) >= 0 {
+		return nil, errInvalidCurvePoint
+	}
+
+	y, onCurve := new(bn256.G1).Unmarshal(in[64:128])
+	if !onCurve {
+		return nil, errNotOnCurve
+	}
+	gx, gy, _, _ = y.CurvePoints()
+	if gx.Cmp(bn256.P) >= 0 || gy.Cmp(bn256.P) >= 0 {
+		return nil, errInvalidCurvePoint
+	}
+	x.Add(x, y)
+
+	return x.Marshal(), nil
+}
+
+type bn256ScalarMul 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 *bn256ScalarMul) RequiredGas(input []byte) uint64 {
+	return 0 // TODO
+}
+
+func (c *bn256ScalarMul) Run(in []byte) ([]byte, error) {
+	in = common.RightPadBytes(in, 96)
+
+	g1, onCurve := new(bn256.G1).Unmarshal(in[:64])
+	if !onCurve {
+		return nil, errNotOnCurve
+	}
+	x, y, _, _ := g1.CurvePoints()
+	if x.Cmp(bn256.P) >= 0 || y.Cmp(bn256.P) >= 0 {
+		return nil, errInvalidCurvePoint
+	}
+	g1.ScalarMult(g1, new(big.Int).SetBytes(in[64:96]))
+
+	return g1.Marshal(), nil
+}
+
+// pairing implements a pairing pre-compile for the bn256 curve
+type pairing 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 *pairing) RequiredGas(input []byte) uint64 {
+	//return 0 // TODO
+	k := (len(input) + 191) / pairSize
+	return uint64(60000*k + 40000)
+}
+
+const pairSize = 192
+
+var (
+	true32Byte           = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
+	fals32Byte           = make([]byte, 32)
+	errNotOnCurve        = errors.New("point not on elliptic curve")
+	errInvalidCurvePoint = errors.New("invalid elliptic curve point")
+)
+
+func (c *pairing) Run(in []byte) ([]byte, error) {
+	if len(in) == 0 {
+		return true32Byte, nil
+	}
+
+	if len(in)%pairSize > 0 {
+		return nil, errBadPrecompileInput
+	}
+
+	var (
+		g1s []*bn256.G1
+		g2s []*bn256.G2
+	)
+	for i := 0; i < len(in); i += pairSize {
+		g1, onCurve := new(bn256.G1).Unmarshal(in[i : i+64])
+		if !onCurve {
+			return nil, errNotOnCurve
+		}
+
+		x, y, _, _ := g1.CurvePoints()
+		if x.Cmp(bn256.P) >= 0 || y.Cmp(bn256.P) >= 0 {
+			return nil, errInvalidCurvePoint
+		}
+
+		g2, onCurve := new(bn256.G2).Unmarshal(in[i+64 : i+192])
+		if !onCurve {
+			return nil, errNotOnCurve
+		}
+		x2, y2, _, _ := g2.CurvePoints()
+		if x2.Real().Cmp(bn256.P) >= 0 || x2.Imag().Cmp(bn256.P) >= 0 ||
+			y2.Real().Cmp(bn256.P) >= 0 || y2.Imag().Cmp(bn256.P) >= 0 {
+			return nil, errInvalidCurvePoint
+		}
+
+		g1s = append(g1s, g1)
+		g2s = append(g2s, g2)
+	}
+
+	isOne := bn256.PairingCheck(g1s, g2s)
+	if isOne {
+		return true32Byte, nil
+	}
+
+	return fals32Byte, nil
+}
diff --git a/core/vm/contracts_test.go b/core/vm/contracts_test.go
index 830a8f69d..2b4070ede 100644
--- a/core/vm/contracts_test.go
+++ b/core/vm/contracts_test.go
@@ -1 +1,35 @@
 package vm
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+const input = ""
+
+func TestPairing(t *testing.T) {
+	pairing := &pairing{}
+
+	for i, test := range []struct {
+		input string
+		valid int
+	}{
+		{"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", 1},
+		{"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", 1},
+		{"0f25929bcb43d5a57391564615c9e70a992b10eafa4db109709649cf48c50dd216da2f5cb6be7a0aa72c440c53c9bbdfec6c36c7d515536431b3a865468acbba2e89718ad33c8bed92e210e81d1853435399a271913a6520736a4729cf0d51eb01a9e2ffa2e92599b68e44de5bcf354fa2642bd4f26b259daa6f7ce3ed57aeb314a9a87b789a58af499b314e13c3d65bede56c07ea2d418d6874857b70763713178fb49a2d6cd347dc58973ff49613a20757d0fcc22079f9abd10c3baee245901b9e027bd5cfc2cb5db82d4dc9677ac795ec500ecd47deee3b5da006d6d049b811d7511c78158de484232fc68daf8a45cf217d1c2fae693ff5871e8752d73b21198e9393920d483a7260bfb731fb5d25f1aa493335a9e71297e485b7aef312c21800deef121f1e76426a00665e5c4479674322d4f75edadd46debd5cd992f6ed090689d0585ff075ec9e99ad690c3395bc4b313370b38ef355acdadcd122975b12c85ea5db8c6deb4aab71808dcb408fe3d1e7690c43d37b4ce6cc0166fa7daa", 1},
+		{"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", 1},
+		{"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", 1},
+		{"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", 0},
+	} {
+		r, err := pairing.Run(common.FromHex(test.input))
+		if err != nil {
+			t.Error(i, ":", err)
+		}
+
+		if int(r[31]) != test.valid {
+			t.Error(i, "expected", test.valid, "but was", r[31])
+		}
+	}
+
+}
diff --git a/core/vm/evm.go b/core/vm/evm.go
index 9296cc7ca..20eaaccb4 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -37,6 +37,10 @@ type (
 func run(evm *EVM, snapshot int, contract *Contract, input []byte) ([]byte, error) {
 	if contract.CodeAddr != nil {
 		precompiledContracts := PrecompiledContracts
+		if evm.ChainConfig().IsMetropolis(evm.BlockNumber) {
+			precompiledContracts = PrecompiledContractsMetropolis
+		}
+
 		if p := precompiledContracts[*contract.CodeAddr]; p != nil {
 			return RunPrecompiledContract(p, input, contract)
 		}
@@ -100,8 +104,8 @@ type EVM struct {
 	abort int32
 }
 
-// NewEVM retutrns a new EVM evmironment. The returned EVM is not thread safe
-// and should only ever be used *once*.
+// NewEVM retutrns a new EVM . The returned EVM is not thread safe and should
+// only ever be used *once*.
 func NewEVM(ctx Context, statedb StateDB, chainConfig *params.ChainConfig, vmConfig Config) *EVM {
 	evm := &EVM{
 		Context:     ctx,