SmartContract: restrict the number of allowed notifications

src/Neo.CLI/config.fs.mainnet.json

@@ -40,7 +40,8 @@
       "HF_Aspidochelone": 3000000,
       "HF_Basilisk": 4500000,
       "HF_Cockatrice": 5800000,
-      "HF_Domovoi": 5800000
+      "HF_Domovoi": 5800000,
+      "HF_Echidna": 5800001
     },
     "StandbyCommittee": [
       "026fa34ec057d74c2fdf1a18e336d0bd597ea401a0b2ad57340d5c220d09f44086",

src/Neo.CLI/config.json

@@ -38,7 +38,8 @@
       "HF_Aspidochelone": 1730000,
       "HF_Basilisk": 4120000,
       "HF_Cockatrice": 5450000,
-      "HF_Domovoi": 5570000
+      "HF_Domovoi": 5570000,
+      "HF_Echidna": 5570001
     },
     "InitialGasDistribution": 5200000000000000,
     "ValidatorsCount": 7,

src/Neo.CLI/config.mainnet.json

@@ -38,7 +38,8 @@
       "HF_Aspidochelone": 1730000,
       "HF_Basilisk": 4120000,
       "HF_Cockatrice": 5450000,
-      "HF_Domovoi": 5570000
+      "HF_Domovoi": 5570000,
+      "HF_Echidna": 5570001
     },
     "InitialGasDistribution": 5200000000000000,
     "ValidatorsCount": 7,

src/Neo.CLI/config.testnet.json

@@ -38,7 +38,8 @@
       "HF_Aspidochelone": 210000,
       "HF_Basilisk": 2680000,
       "HF_Cockatrice": 3967000,
-      "HF_Domovoi": 4144000
+      "HF_Domovoi": 4144000,
+      "HF_Echidna": 4144001
     },
     "InitialGasDistribution": 5200000000000000,
     "ValidatorsCount": 7,

src/Neo/Hardfork.cs

@@ -16,6 +16,7 @@ public enum Hardfork : byte
         HF_Aspidochelone,
         HF_Basilisk,
         HF_Cockatrice,
-        HF_Domovoi
+        HF_Domovoi,
+        HF_Echidna
     }
 }

src/Neo/Neo.csproj

@@ -16,6 +16,7 @@
     <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="8.0.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="8.0.2" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="8.0.0" />
+    <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="8.0.1" />
   </ItemGroup>
 
   <ItemGroup>

src/Neo/SmartContract/ApplicationEngine.Runtime.cs

@@ -36,6 +36,11 @@ partial class ApplicationEngine
         /// </summary>
         public const int MaxNotificationSize = 1024;
 
+        /// <summary>
+        /// The maximum number of notifications per application execution.
+        /// </summary>
+        public const int MaxNotificationCount = 512;
+
         private uint random_times = 0;
 
         /// <summary>
@@ -395,8 +400,15 @@ protected internal void RuntimeNotifyV1(byte[] eventName, Array state)
         protected internal void SendNotification(UInt160 hash, string eventName, Array state)
         {
             NotifyEventArgs notification = new(ScriptContainer, hash, eventName, (Array)state.DeepCopy(asImmutable: true));
-            Notify?.Invoke(this, notification);
             notifications ??= new List<NotifyEventArgs>();
+            // Restrict the number of notifications for Application executions. Do not check
+            // persisting triggers to avoid native persist failure. Do not check verification
+            // trigger since verification context is loaded with ReadOnly flag.
+            if (IsHardforkEnabled(Hardfork.HF_Echidna) && Trigger == TriggerType.Application && notifications.Count >= MaxNotificationCount)
+            {
+                throw new InvalidOperationException($"Maximum number of notifications `{MaxNotificationCount}` is reached.");
+            }
+            Notify?.Invoke(this, notification);
             notifications.Add(notification);
             CurrentContext.GetState<ExecutionContextState>().NotificationCount++;
         }

src/Neo/SmartContract/Native/RoleManagement.cs

@@ -26,7 +26,16 @@
     {
         [ContractEvent(0, name: "Designation",
             "Role", ContractParameterType.Integer,
-            "BlockIndex", ContractParameterType.Integer)]
+            "BlockIndex", ContractParameterType.Integer,
+            Hardfork.HF_Echidna)]
+
+        [ContractEvent(Hardfork.HF_Echidna, 0, name: "Designation",
+            "Role", ContractParameterType.Integer,
+            "BlockIndex", ContractParameterType.Integer,
+            "Old", ContractParameterType.Array,
+            "New", ContractParameterType.Array
+            )]
+
         internal RoleManagement() : base() { }
 
         /// <summary>
@@ -69,7 +78,18 @@
             list.AddRange(nodes);
             list.Sort();
             engine.SnapshotCache.Add(key, new StorageItem(list));
-            engine.SendNotification(Hash, "Designation", new VM.Types.Array(engine.ReferenceCounter, new StackItem[] { (int)role, engine.PersistingBlock.Index }));
+
+            if (engine.IsHardforkEnabled(Hardfork.HF_Echidna))
+            {
+                var oldNodes = new VM.Types.Array(engine.ReferenceCounter, GetDesignatedByRole(engine.Snapshot, role, index - 1).Select(u => (ByteString)u.EncodePoint(true)));
+                var newNodes = new VM.Types.Array(engine.ReferenceCounter, nodes.Select(u => (ByteString)u.EncodePoint(true)));
+
+                engine.SendNotification(Hash, "Designation", new VM.Types.Array(engine.ReferenceCounter, [(int)role, engine.PersistingBlock.Index, oldNodes, newNodes]));
+            }
+            else
+            {
+                engine.SendNotification(Hash, "Designation", new VM.Types.Array(engine.ReferenceCounter, [(int)role, engine.PersistingBlock.Index]));
+            }
         }
 
         private class NodeList : InteroperableList<ECPoint>

src/Neo/SmartContract/Native/StdLib.cs

@@ -11,6 +11,7 @@
 
 #pragma warning disable IDE0051
 
+using Microsoft.IdentityModel.Tokens;
 using Neo.Cryptography;
 using Neo.Json;
 using Neo.VM.Types;
@@ -131,6 +132,28 @@ public static byte[] Base64Decode([MaxLength(MaxInputLength)] string s)
             return Convert.FromBase64String(s);
         }
 
+        /// <summary>
+        /// Encodes a byte array into a base64Url string.
+        /// </summary>
+        /// <param name="data">The base64Url to be encoded.</param>
+        /// <returns>The encoded base64Url string.</returns>
+        [ContractMethod(Hardfork.HF_Echidna, CpuFee = 1 << 5)]
+        public static string Base64UrlEncode([MaxLength(MaxInputLength)] string data)
+        {
+            return Base64UrlEncoder.Encode(data);
+        }
+
+        /// <summary>
+        /// Decodes a byte array from a base64Url string.
+        /// </summary>
+        /// <param name="s">The base64Url string.</param>
+        /// <returns>The decoded base64Url string.</returns>
+        [ContractMethod(Hardfork.HF_Echidna, CpuFee = 1 << 5)]
+        public static string Base64UrlDecode([MaxLength(MaxInputLength)] string s)
+        {
+            return Base64UrlEncoder.Decode(s);
+        }
+
         /// <summary>
         /// Encodes a byte array into a base58 <see cref="string"/>.
         /// </summary>

tests/Neo.UnitTests/SmartContract/Native/UT_StdLib.cs

@@ -406,5 +406,25 @@ public void TestRuntime_Deserialize()
             Assert.AreEqual(engine.ResultStack.Pop<Integer>().GetInteger(), 100);
             Assert.AreEqual(engine.ResultStack.Pop<ByteString>().GetString(), "test");
         }
+
+        [TestMethod]
+        public void TestBase64Url()
+        {
+            var snapshotCache = TestBlockchain.GetTestSnapshotCache();
+            using (var script = new ScriptBuilder())
+            {
+                // Test encoding
+                script.EmitDynamicCall(NativeContract.StdLib.Hash, "base64UrlEncode", "[email protected]&Issuer=https://example.com");
+                script.EmitDynamicCall(NativeContract.StdLib.Hash, "base64UrlDecode", "U3ViamVjdD10ZXN0QGV4YW1wbGUuY29tJklzc3Vlcj1odHRwczovL2V4YW1wbGUuY29t");
+
+                using var engine = ApplicationEngine.Create(TriggerType.Application, null, snapshotCache, settings: TestBlockchain.TheNeoSystem.Settings);
+                engine.LoadScript(script.ToArray());
+
+                Assert.AreEqual(engine.Execute(), VMState.HALT);
+                Assert.AreEqual(2, engine.ResultStack.Count);
+                Assert.AreEqual("[email protected]&Issuer=https://example.com", engine.ResultStack.Pop<ByteString>());
+                Assert.AreEqual("U3ViamVjdD10ZXN0QGV4YW1wbGUuY29tJklzc3Vlcj1odHRwczovL2V4YW1wbGUuY29t", engine.ResultStack.Pop<ByteString>().GetString());
+            }
+        }
     }
 }