From 0b2e9312afbcbbdb0dec1f28ced1edd9dcc73d71 Mon Sep 17 00:00:00 2001
From: Roman Khimov <roman@nspcc.ru>
Date: Mon, 8 Feb 2021 17:38:03 +0300
Subject: [PATCH] manifest: add event validity check

Refs. #1699.
---
 pkg/smartcontract/manifest/abi.go           |  6 ++++++
 pkg/smartcontract/manifest/event.go         | 24 +++++++++++++++++++++
 pkg/smartcontract/manifest/event_test.go    | 23 ++++++++++++++++++++
 pkg/smartcontract/manifest/manifest_test.go | 24 ++++++++++++++++++++-
 4 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/pkg/smartcontract/manifest/abi.go b/pkg/smartcontract/manifest/abi.go
index ee14e25c9..443002ed3 100644
--- a/pkg/smartcontract/manifest/abi.go
+++ b/pkg/smartcontract/manifest/abi.go
@@ -54,6 +54,12 @@ func (a *ABI) IsValid() error {
 	if len(a.Methods) == 0 {
 		return errors.New("ABI contains no methods")
 	}
+	for i := range a.Events {
+		err := a.Events[i].IsValid()
+		if err != nil {
+			return err
+		}
+	}
 	return nil
 }
 
diff --git a/pkg/smartcontract/manifest/event.go b/pkg/smartcontract/manifest/event.go
index a80b13902..a6fd44349 100644
--- a/pkg/smartcontract/manifest/event.go
+++ b/pkg/smartcontract/manifest/event.go
@@ -2,6 +2,7 @@ package manifest
 
 import (
 	"errors"
+	"sort"
 
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 )
@@ -12,6 +13,29 @@ type Event struct {
 	Parameters []Parameter `json:"parameters"`
 }
 
+// IsValid checks Event consistency and correctness.
+func (e *Event) IsValid() error {
+	if e.Name == "" {
+		return errors.New("empty or absent name")
+	}
+	if len(e.Parameters) > 1 {
+		paramNames := make([]string, len(e.Parameters))
+		for i := range e.Parameters {
+			paramNames[i] = e.Parameters[i].Name
+		}
+		sort.Strings(paramNames)
+		for i := range paramNames {
+			if i == 0 {
+				continue
+			}
+			if paramNames[i] == paramNames[i-1] {
+				return errors.New("duplicate parameter name")
+			}
+		}
+	}
+	return nil
+}
+
 // ToStackItem converts Event to stackitem.Item.
 func (e *Event) ToStackItem() stackitem.Item {
 	params := make([]stackitem.Item, len(e.Parameters))
diff --git a/pkg/smartcontract/manifest/event_test.go b/pkg/smartcontract/manifest/event_test.go
index 81c63c755..2e50bdd46 100644
--- a/pkg/smartcontract/manifest/event_test.go
+++ b/pkg/smartcontract/manifest/event_test.go
@@ -9,6 +9,29 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func TestEventIsValid(t *testing.T) {
+	e := Event{}
+	require.Error(t, e.IsValid())
+
+	e.Name = "some"
+	require.NoError(t, e.IsValid())
+
+	e.Parameters = make([]Parameter, 0)
+	require.NoError(t, e.IsValid())
+
+	e.Parameters = append(e.Parameters, NewParameter("p1", smartcontract.BoolType))
+	require.NoError(t, e.IsValid())
+
+	e.Parameters = append(e.Parameters, NewParameter("p2", smartcontract.IntegerType))
+	require.NoError(t, e.IsValid())
+
+	e.Parameters = append(e.Parameters, NewParameter("p3", smartcontract.IntegerType))
+	require.NoError(t, e.IsValid())
+
+	e.Parameters = append(e.Parameters, NewParameter("p1", smartcontract.IntegerType))
+	require.Error(t, e.IsValid())
+}
+
 func TestEvent_ToStackItemFromStackItem(t *testing.T) {
 	m := &Event{
 		Name:       "mur",
diff --git a/pkg/smartcontract/manifest/manifest_test.go b/pkg/smartcontract/manifest/manifest_test.go
index f5d03ca4d..834be1b4e 100644
--- a/pkg/smartcontract/manifest/manifest_test.go
+++ b/pkg/smartcontract/manifest/manifest_test.go
@@ -121,10 +121,32 @@ func TestIsValid(t *testing.T) {
 		Parameters: []Parameter{},
 	})
 
-	t.Run("valid, no groups", func(t *testing.T) {
+	t.Run("valid, no groups/events", func(t *testing.T) {
 		require.NoError(t, m.IsValid(contractHash))
 	})
 
+	m.ABI.Events = append(m.ABI.Events, Event{
+		Name:       "itHappened",
+		Parameters: []Parameter{},
+	})
+
+	t.Run("valid, with events", func(t *testing.T) {
+		require.NoError(t, m.IsValid(contractHash))
+	})
+
+	m.ABI.Events = append(m.ABI.Events, Event{
+		Name: "itHappened",
+		Parameters: []Parameter{
+			NewParameter("qwerty", smartcontract.IntegerType),
+			NewParameter("qwerty", smartcontract.IntegerType),
+		},
+	})
+
+	t.Run("invalid, bad event", func(t *testing.T) {
+		require.Error(t, m.IsValid(contractHash))
+	})
+	m.ABI.Events = m.ABI.Events[:1]
+
 	t.Run("with groups", func(t *testing.T) {
 		m.Groups = make([]Group, 3)
 		pks := make([]*keys.PrivateKey, 3)