From 5a30af2c75d39a8d3e21a4c06458b2d04846873d Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Wed, 18 Mar 2020 12:41:09 +0300
Subject: [PATCH] core: implement Neo.Crypto.ECDsaVerify interop

---
 pkg/core/interop/crypto/ecdsa.go | 31 ++++++++++++++++
 pkg/core/interop_neo_test.go     | 63 ++++++++++++++++++++++++++++++++
 pkg/core/interops.go             |  2 +
 3 files changed, 96 insertions(+)
 create mode 100644 pkg/core/interop/crypto/ecdsa.go

diff --git a/pkg/core/interop/crypto/ecdsa.go b/pkg/core/interop/crypto/ecdsa.go
new file mode 100644
index 000000000..ab7f5b6b5
--- /dev/null
+++ b/pkg/core/interop/crypto/ecdsa.go
@@ -0,0 +1,31 @@
+package crypto
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
+	"github.com/nspcc-dev/neo-go/pkg/vm"
+)
+
+// ECDSAVerify checks ECDSA signature.
+func ECDSAVerify(ic *interop.Context, v *vm.VM) error {
+	msg := getMessage(ic, v.Estack().Pop().Item())
+	hashToCheck := hash.Sha256(msg).BytesBE()
+	keyb := v.Estack().Pop().Bytes()
+	signature := v.Estack().Pop().Bytes()
+	pkey, err := keys.NewPublicKeyFromBytes(keyb)
+	if err != nil {
+		return err
+	}
+	res := pkey.Verify(signature, hashToCheck)
+	v.Estack().PushVal(res)
+	return nil
+}
+
+func getMessage(_ *interop.Context, item vm.StackItem) []byte {
+	msg, err := item.TryBytes()
+	if err != nil {
+		panic(err)
+	}
+	return msg
+}
diff --git a/pkg/core/interop_neo_test.go b/pkg/core/interop_neo_test.go
index 26068690f..7253edb17 100644
--- a/pkg/core/interop_neo_test.go
+++ b/pkg/core/interop_neo_test.go
@@ -1,12 +1,14 @@
 package core
 
 import (
+	"fmt"
 	"math/big"
 	"testing"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/enumerator"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/iterator"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
@@ -231,6 +233,67 @@ func TestWitnessGetVerificationScript(t *testing.T) {
 	require.Equal(t, witness.VerificationScript, value)
 }
 
+func TestECDSAVerify(t *testing.T) {
+	priv, err := keys.NewPrivateKey()
+	require.NoError(t, err)
+
+	chain := newTestChain(t)
+	defer chain.Close()
+
+	ic := chain.newInteropContext(trigger.Application, dao.NewSimple(storage.NewMemoryStore()), nil, nil)
+	runCase := func(t *testing.T, isErr bool, result interface{}, args ...interface{}) {
+		v := vm.New()
+		for i := range args {
+			v.Estack().PushVal(args[i])
+		}
+
+		var err error
+		func() {
+			defer func() {
+				if r := recover(); r != nil {
+					err = fmt.Errorf("panic: %v", r)
+				}
+			}()
+			err = crypto.ECDSAVerify(ic, v)
+		}()
+
+		if isErr {
+			require.Error(t, err)
+			return
+		}
+		require.NoError(t, err)
+		require.Equal(t, 1, v.Estack().Len())
+		require.Equal(t, result, v.Estack().Pop().Value().(bool))
+	}
+
+	msg := []byte("test message")
+
+	t.Run("success", func(t *testing.T) {
+		sign := priv.Sign(msg)
+		runCase(t, false, true, sign, priv.PublicKey().Bytes(), msg)
+	})
+
+	t.Run("missing arguments", func(t *testing.T) {
+		runCase(t, true, false)
+		sign := priv.Sign(msg)
+		runCase(t, true, false, sign)
+		runCase(t, true, false, sign, priv.PublicKey().Bytes())
+	})
+
+	t.Run("invalid signature", func(t *testing.T) {
+		sign := priv.Sign(msg)
+		sign[0] ^= sign[0]
+		runCase(t, false, false, sign, priv.PublicKey().Bytes(), msg)
+	})
+
+	t.Run("invalid public key", func(t *testing.T) {
+		sign := priv.Sign(msg)
+		pub := priv.PublicKey().Bytes()
+		pub = pub[10:]
+		runCase(t, true, false, sign, pub, msg)
+	})
+}
+
 func TestPopInputFromVM(t *testing.T) {
 	v, tx, _, chain := createVMAndTX(t)
 	defer chain.Close()
diff --git a/pkg/core/interops.go b/pkg/core/interops.go
index edcdb3310..751035f7d 100644
--- a/pkg/core/interops.go
+++ b/pkg/core/interops.go
@@ -11,6 +11,7 @@ import (
 	"sort"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/enumerator"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/iterator"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
@@ -137,6 +138,7 @@ var neoInterops = []interop.Function{
 	{Name: "Neo.Contract.GetStorageContext", Func: contractGetStorageContext, Price: 1},
 	{Name: "Neo.Contract.IsPayable", Func: contractIsPayable, Price: 1},
 	{Name: "Neo.Contract.Migrate", Func: contractMigrate, Price: 0},
+	{Name: "Neo.Crypto.ECDsaVerify", Func: crypto.ECDSAVerify, Price: 1},
 	{Name: "Neo.Enumerator.Concat", Func: enumerator.Concat, Price: 1},
 	{Name: "Neo.Enumerator.Create", Func: enumerator.Create, Price: 1},
 	{Name: "Neo.Enumerator.Next", Func: enumerator.Next, Price: 1},