[ETCM-797] Implement a correct seed calculation for block validation

* fix bug seed calculation

* [ETCM-797] add testcase for ecip 1099 seed bug

* [ETCM-797] add debug endpoint to request a specific block (by number) from connected peers

* refactor EthashUtils.seed and add a comment

* Revert "[ETCM-797] add debug endpoint to request a specific block (by number) from connected peers"

This reverts commit 48b39b5.

* remove ecip1099ActivationBlock parameter from EthashDAGManager

Co-authored-by: Jaap van der Plas <[email protected]>

Author: bsuieric

src/main/scala/io/iohk/ethereum/consensus/pow/EthashDAGManager.scala

@@ -17,7 +17,7 @@ class EthashDAGManager(blockCreator: EthashBlockCreator) extends Logger {
     (currentEpoch, currentEpochDag, currentEpochDagSize) match {
       case (Some(`epoch`), Some(dag), Some(dagSize)) => (dag, dagSize)
       case _ =>
-        val seed = EthashUtils.seed(blockNumber)
+        val seed = EthashUtils.seed(blockNumber, blockCreator.blockchainConfig.ecip1099BlockNumber.toLong)
         val dagSize = EthashUtils.dagSize(epoch)
         val dagNumHashes = (dagSize / EthashUtils.HASH_BYTES).toInt
         val dag =

src/main/scala/io/iohk/ethereum/consensus/pow/EthashUtils.scala

@@ -61,10 +61,15 @@ object EthashUtils {
 
   // scalastyle:on magic.number
 
-  private def epochBeforeEcip1099(blockNumber: Long): Long = blockNumber / EPOCH_LENGTH_BEFORE_ECIP_1099
+  // computes seed for epoch of given blockNumber
+  // this also involves the non-ECIP1099 epoch of the first blocks of the
+  // ECIP1099 epoch, to make sure every block in the latter results in the same
+  // seed being calculated, would there be a cache miss.
+  def seed(blockNumber: Long, ecip1099ActivationBlock: Long): ByteString = {
+    val epochLength = calcEpochLength(blockNumber, ecip1099ActivationBlock)
+    val startBlock = (blockNumber / epochLength) * epochLength + 1
+    val epoch = startBlock / EPOCH_LENGTH_BEFORE_ECIP_1099
 
-  def seed(blockNumber: Long): ByteString = {
-    val epoch = epochBeforeEcip1099(blockNumber)
     (BigInt(0) until epoch)
       .foldLeft(ByteString(Hex.decode("00" * 32))) { case (b, _) => kec256(b) }
   }

src/main/scala/io/iohk/ethereum/consensus/pow/validators/EthashBlockHeaderValidator.scala

@@ -42,7 +42,7 @@ class EthashBlockHeaderValidator(blockchainConfig: BlockchainConfig) {
     }
 
     val epoch = EthashUtils.epoch(blockHeader.number.toLong, blockchainConfig.ecip1099BlockNumber.toLong)
-    val seed = EthashUtils.seed(blockHeader.number.toLong)
+    val seed = EthashUtils.seed(blockHeader.number.toLong, blockchainConfig.ecip1099BlockNumber.toLong)
     val powCacheData = getPowCacheData(epoch, seed)
 
     val proofOfWork = hashimotoLight(

src/main/scala/io/iohk/ethereum/jsonrpc/EthMiningService.scala

@@ -21,6 +21,7 @@ import scala.collection.concurrent.{TrieMap, Map => ConcurrentMap}
 import scala.concurrent.duration.FiniteDuration
 import scala.language.existentials
 import io.iohk.ethereum.transactions.TransactionPicker
+import io.iohk.ethereum.utils.BlockchainConfig
 
 object EthMiningService {
 
@@ -45,6 +46,7 @@ object EthMiningService {
 
 class EthMiningService(
     blockchain: Blockchain,
+    blockchainConfig: BlockchainConfig,
     ledger: Ledger,
     jsonRpcConfig: JsonRpcConfig,
     ommersPool: ActorRef,
@@ -92,7 +94,7 @@ class EthMiningService(
             Right(
               GetWorkResponse(
                 powHeaderHash = ByteString(kec256(BlockHeader.getEncodedWithoutNonce(pb.block.header))),
-                dagSeed = EthashUtils.seed(pb.block.header.number.toLong),
+                dagSeed = EthashUtils.seed(pb.block.header.number.toLong, blockchainConfig.ecip1099BlockNumber.toLong),
                 target = ByteString((BigInt(2).pow(256) / pb.block.header.difficulty).toByteArray)
               )
             )

src/main/scala/io/iohk/ethereum/nodebuilder/NodeBuilder.scala

@@ -405,6 +405,7 @@ trait EthInfoServiceBuilder {
 
 trait EthMiningServiceBuilder {
   self: BlockchainBuilder
+    with BlockchainConfigBuilder
     with LedgerBuilder
     with JSONRpcConfigBuilder
     with OmmersPoolBuilder
@@ -414,6 +415,7 @@ trait EthMiningServiceBuilder {
 
   lazy val ethMiningService = new EthMiningService(
     blockchain,
+    blockchainConfig,
     ledger,
     jsonRpcConfig,
     ommersPool,

src/test/scala/io/iohk/ethereum/consensus/pow/EthashUtilsSpec.scala

@@ -10,6 +10,8 @@ import org.scalatest.matchers.should.Matchers
 
 import scala.annotation.tailrec
 import io.iohk.ethereum.SuperSlow
+import io.iohk.ethereum.utils.ByteStringUtils
+import org.scalatest.prop.TableFor2
 
 class EthashUtilsSpec extends AnyFlatSpec with Matchers with ScalaCheckPropertyChecks with SuperSlow {
 
@@ -18,8 +20,21 @@ class EthashUtilsSpec extends AnyFlatSpec with Matchers with ScalaCheckPropertyC
   val ecip1099forkBlockNumber: Long = 11460000
 
   "Ethash" should "generate correct hash" in {
-    forAll(Gen.choose[Long](0, 15000000L)) { blockNumber =>
-      seed(blockNumber) shouldBe seedForBlockReference(blockNumber)
+    val seedEpoch0 = ByteStringUtils.string2hash("0000000000000000000000000000000000000000000000000000000000000000")
+    val seedEpoch1 = ByteStringUtils.string2hash("290decd9548b62a8d60345a988386fc84ba6bc95484008f6362f93160ef3e563")
+    val seedEpoch382 = ByteStringUtils.string2hash("d3d0aa11197dcdcfcb3ad3c73d415af47299bddb47fda6081d31d9dd06462f6a")
+    val seedEpoch383 = ByteStringUtils.string2hash("bf532874eb434842e7a3e4acd113fe454541651872760d9b95d11d7f90ca25dc")
+    val table: TableFor2[Long, ByteString] = Table(
+      ("blockNumber", "referenceSeed"),
+      (0, seedEpoch0),
+      (1, seedEpoch0),
+      (30_000, seedEpoch1),
+      (ecip1099forkBlockNumber, seedEpoch382),
+      (ecip1099forkBlockNumber + 30_000, seedEpoch382),
+      (ecip1099forkBlockNumber + 60_000, seedEpoch383)
+    )
+    forAll(table) { (blockNumber, referenceSeed) =>
+      seed(blockNumber, ecip1099forkBlockNumber) shouldBe referenceSeed
     }
   }
 
@@ -55,7 +70,7 @@ class EthashUtilsSpec extends AnyFlatSpec with Matchers with ScalaCheckPropertyC
 
     val blockNumber = 486382
     val _epoch = epoch(blockNumber, ecip1099forkBlockNumber)
-    val _seed = seed(blockNumber)
+    val _seed = seed(blockNumber, ecip1099forkBlockNumber)
     val cache = makeCache(_epoch, _seed)
     val proofOfWork = hashimotoLight(hash, nonce, dagSize(_epoch), cache)
 
@@ -129,25 +144,12 @@ class EthashUtilsSpec extends AnyFlatSpec with Matchers with ScalaCheckPropertyC
 
       forAll(table) { (blockNumber, hashWithoutNonce, nonce, mixHash) =>
         val _epoch = epoch(blockNumber, ecip1099forkBlockNumber)
-        val _seed = seed(blockNumber)
+        val _seed = seed(blockNumber, ecip1099forkBlockNumber)
         val cache = makeCache(_epoch, _seed)
         val proofOfWork =
           hashimotoLight(Hex.decode(hashWithoutNonce), Hex.decode(nonce), dagSize(_epoch), cache)
         proofOfWork.mixHash shouldBe ByteString(Hex.decode(mixHash))
       }
     }
   }
-
-  def seedForBlockReference(blockNumber: BigInt): ByteString = {
-    @tailrec
-    def go(current: BigInt, currentHash: ByteString): ByteString = {
-      if (current < EPOCH_LENGTH_BEFORE_ECIP_1099) {
-        currentHash
-      } else {
-        go(current - EPOCH_LENGTH_BEFORE_ECIP_1099, kec256(currentHash))
-      }
-    }
-
-    go(blockNumber, ByteString(Hex.decode("00" * 32)))
-  }
 }

src/test/scala/io/iohk/ethereum/jsonrpc/EthMiningServiceSpec.scala

@@ -249,6 +249,7 @@ class EthMiningServiceSpec
 
     lazy val ethMiningService = new EthMiningService(
       blockchain,
+      blockchainConfig,
       ledger,
       jsonRpcConfig,
       ommersPool.ref,

src/test/scala/io/iohk/ethereum/jsonrpc/JsonRpcControllerFixture.scala

@@ -85,6 +85,7 @@ class JsonRpcControllerFixture(implicit system: ActorSystem)
 
   val ethMiningService = new EthMiningService(
     blockchain,
+    blockchainConfig,
     ledger,
     config,
     ommersPool.ref,