[ETCM-844] Validate peer fork id during eth/64 handshake (#1064)

* [ETCM-844] Validate peer fork id

* [ETCM-844] Apply review suggestion

Author: lukasz-golebiewski

src/main/scala/io/iohk/ethereum/forkid/ForkIdValidator.scala

@@ -22,9 +22,12 @@ case object Connect extends ForkIdValidationResult
 case object ErrRemoteStale extends ForkIdValidationResult
 case object ErrLocalIncompatibleOrStale extends ForkIdValidationResult
 
+import cats.effect._
+
 object ForkIdValidator {
 
-  implicit val unsafeLogger: SelfAwareStructuredLogger[Task] = Slf4jLogger.getLogger[Task]
+  implicit val taskLogger: SelfAwareStructuredLogger[Task] = Slf4jLogger.getLogger[Task]
+  implicit val syncIoLogger: SelfAwareStructuredLogger[SyncIO] = Slf4jLogger.getLogger[SyncIO]
 
   val maxUInt64: BigInt = (BigInt(0x7fffffffffffffffL) << 1) + 1 // scalastyle:ignore magic.number
 

src/main/scala/io/iohk/ethereum/network/handshaker/EthNodeStatus64ExchangeState.scala

@@ -1,12 +1,17 @@
 package io.iohk.ethereum.network.handshaker
 
+import cats.effect.SyncIO
+
+import io.iohk.ethereum.forkid.Connect
 import io.iohk.ethereum.forkid.ForkId
+import io.iohk.ethereum.forkid.ForkIdValidator
 import io.iohk.ethereum.network.EtcPeerManagerActor.PeerInfo
 import io.iohk.ethereum.network.EtcPeerManagerActor.RemoteStatus
 import io.iohk.ethereum.network.p2p.Message
 import io.iohk.ethereum.network.p2p.MessageSerializable
 import io.iohk.ethereum.network.p2p.messages.Capability
 import io.iohk.ethereum.network.p2p.messages.ETH64
+import io.iohk.ethereum.network.p2p.messages.WireProtocol.Disconnect
 
 case class EthNodeStatus64ExchangeState(
     handshakerConfiguration: EtcHandshakerConfiguration
@@ -15,8 +20,17 @@ case class EthNodeStatus64ExchangeState(
   import handshakerConfiguration._
 
   def applyResponseMessage: PartialFunction[Message, HandshakerState[PeerInfo]] = { case status: ETH64.Status =>
-    // TODO: validate fork id of the remote peer
-    applyRemoteStatusMessage(RemoteStatus(status))
+    import ForkIdValidator.syncIoLogger
+    (for {
+      validationResult <-
+        ForkIdValidator.validatePeer[SyncIO](blockchainReader.genesisHeader.hash, blockchainConfig)(
+          blockchainReader.getBestBlockNumber(),
+          status.forkId
+        )
+    } yield validationResult match {
+      case Connect => applyRemoteStatusMessage(RemoteStatus(status))
+      case _       => DisconnectedState[PeerInfo](Disconnect.Reasons.UselessPeer)
+    }).unsafeRunSync()
   }
 
   override protected def createStatusMsg(): MessageSerializable = {

src/test/scala/io/iohk/ethereum/network/handshaker/EtcHandshakerSpec.scala

@@ -190,7 +190,8 @@ class EtcHandshakerSpec extends AnyFlatSpec with Matchers {
     }
   }
 
-  it should "send status with fork id when peer supports ETH64" in new LocalPeerETH64Setup with RemotePeerETH64Setup {
+  it should "connect correctly after validating fork id when peer supports ETH64" in new LocalPeerETH64Setup
+    with RemotePeerETH64Setup {
 
     val newChainWeight = ChainWeight.zero.increase(genesisBlock.header).increase(firstBlock.header)
 
@@ -223,6 +224,45 @@ class EtcHandshakerSpec extends AnyFlatSpec with Matchers {
     }
   }
 
+  it should "disconnect from a useless peer after validating fork id when peer supports ETH64" in new LocalPeerETH64Setup
+    with RemotePeerETH64Setup {
+
+    val newChainWeight = ChainWeight.zero.increase(genesisBlock.header).increase(firstBlock.header)
+
+    blockchainWriter.save(firstBlock, Nil, newChainWeight, saveAsBestBlock = true)
+
+    val newLocalStatusMsg =
+      localStatusMsg
+        .copy(
+          bestHash = firstBlock.header.hash,
+          totalDifficulty = newChainWeight.totalDifficulty,
+          forkId = ForkId(0xfc64ec04L, Some(1150000))
+        )
+
+    initHandshakerWithoutResolver.nextMessage.map(_.messageToSend) shouldBe Right(localHello: HelloEnc)
+
+    val newRemoteStatusMsg =
+      remoteStatusMsg
+        .copy(
+          forkId = ForkId(1, None) // ForkId that is incompatible with our chain
+        )
+
+    val handshakerAfterHelloOpt = initHandshakerWithoutResolver.applyMessage(remoteHello)
+    assert(handshakerAfterHelloOpt.isDefined)
+
+    handshakerAfterHelloOpt.get.nextMessage.map(_.messageToSend.underlyingMsg) shouldBe Right(newLocalStatusMsg)
+
+    val handshakerAfterStatusOpt = handshakerAfterHelloOpt.get.applyMessage(newRemoteStatusMsg)
+    assert(handshakerAfterStatusOpt.isDefined)
+
+    handshakerAfterStatusOpt.get.nextMessage match {
+      case Left(HandshakeFailure(Disconnect.Reasons.UselessPeer)) => succeed
+      case other =>
+        fail(s"Invalid handshaker state: $other")
+    }
+
+  }
+
   it should "fail if a timeout happened during hello exchange" in new TestSetup {
     val handshakerAfterTimeout = initHandshakerWithoutResolver.processTimeout
     handshakerAfterTimeout.nextMessage.map(_.messageToSend) shouldBe Left(
@@ -447,7 +487,7 @@ class EtcHandshakerSpec extends AnyFlatSpec with Matchers {
       totalDifficulty = 0,
       bestHash = genesisBlock.header.hash,
       genesisHash = genesisBlock.header.hash,
-      forkId = ForkId(2L, Some(3L))
+      forkId = ForkId(0xfc64ec04L, Some(1150000))
     )
 
     val remoteStatus: RemoteStatus = RemoteStatus(remoteStatusMsg)