light: fix txpool causes panic on reorgOnNewHead

core/headerchain.go

@@ -225,6 +225,9 @@ type WhCallback func(*types.Header) error
 func (hc *HeaderChain) ValidateHeaderChain(chain []*types.Header, checkFreq int) (int, error) {
 	// Do a sanity check that the provided chain is actually ordered and linked
 	for i := 1; i < len(chain); i++ {
+		if chain[i] == nil {
+			return 0, fmt.Errorf("header was nil")
+		}
 		if chain[i].Number.Uint64() != chain[i-1].Number.Uint64()+1 || chain[i].ParentHash != chain[i-1].Hash() {
 			// Chain broke ancestry, log a message (programming error) and skip insertion
 			log.Error("Non contiguous header insert", "number", chain[i].Number, "hash", chain[i].Hash(),
@@ -291,6 +294,9 @@ func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, writeHeader WhCa
 			log.Debug("Premature abort during headers import")
 			return i, errors.New("aborted")
 		}
+		if header == nil {
+			return i, fmt.Errorf("nil header")
+		}
 		// If the header's already known, skip it, otherwise store
 		hash := header.Hash()
 		if hc.HasHeader(hash, header.Number.Uint64()) {

light/txpool.go

@@ -223,6 +223,15 @@ func (pool *TxPool) rollbackTxs(hash common.Hash, txc txStateChanges) {
 func (pool *TxPool) reorgOnNewHead(ctx context.Context, newHeader *types.Header) (txStateChanges, error) {
 	txc := make(txStateChanges)
 	oldh := pool.chain.GetHeaderByHash(pool.head)
+	if oldh == nil {
+		current := pool.chain.CurrentHeader()
+		if current.Number.Uint64() > 0 {
+			oldh = pool.chain.GetHeaderByHash(current.ParentHash)
+		} else {
+			oldh = current
+		}
+		pool.head = oldh.Hash()
+	}
 	newh := newHeader
 	// find common ancestor, create list of rolled back and new block hashes
 	var oldHashes, newHashes []common.Hash
@@ -308,7 +317,15 @@ func (pool *TxPool) setNewHead(head *types.Header) {
 	ctx, cancel := context.WithTimeout(context.Background(), blockCheckTimeout)
 	defer cancel()
 
-	txc, _ := pool.reorgOnNewHead(ctx, head)
+	if head == nil {
+		return
+	}
+
+	txc, err := pool.reorgOnNewHead(ctx, head)
+	if err != nil {
+		log.Info("light.txpool reorg failed", "error", err)
+		return
+	}
 	m, r := txc.getLists()
 	pool.relay.NewHead(pool.head, m, r)
 	pool.eip2f = pool.config.IsEnabled(pool.config.GetEthashEIP2Transition, head.Number)

light/txpool_test.go

@@ -53,33 +53,33 @@ func (self *testTxRelay) Discard(hashes []common.Hash) {
 	self.discard <- len(hashes)
 }
 
-const poolTestTxs = 1000
-const poolTestBlocks = 100
+const poolTestTxsN = 1000
+const poolTestBlocksN = 100
 
 // test tx 0..n-1
-var testTx [poolTestTxs]*types.Transaction
+var testTxSet [poolTestTxsN]*types.Transaction
 
 // txs sent before block i
 func sentTx(i int) int {
-	return int(math.Pow(float64(i)/float64(poolTestBlocks), 0.9) * poolTestTxs)
+	return int(math.Pow(float64(i)/float64(poolTestBlocksN), 0.9) * poolTestTxsN)
 }
 
 // txs included in block i or before that (minedTx(i) <= sentTx(i))
 func minedTx(i int) int {
-	return int(math.Pow(float64(i)/float64(poolTestBlocks), 1.1) * poolTestTxs)
+	return int(math.Pow(float64(i)/float64(poolTestBlocksN), 1.1) * poolTestTxsN)
 }
 
 func txPoolTestChainGen(i int, block *core.BlockGen) {
 	s := minedTx(i)
 	e := minedTx(i + 1)
 	for i := s; i < e; i++ {
-		block.AddTx(testTx[i])
+		block.AddTx(testTxSet[i])
 	}
 }
 
 func TestTxPool(t *testing.T) {
-	for i := range testTx {
-		testTx[i], _ = types.SignTx(types.NewTransaction(uint64(i), acc1Addr, big.NewInt(10000), vars.TxGas, nil, nil), types.HomesteadSigner{}, testBankKey)
+	for i := range testTxSet {
+		testTxSet[i], _ = types.SignTx(types.NewTransaction(uint64(i), acc1Addr, big.NewInt(10000), vars.TxGas, nil, nil), types.HomesteadSigner{}, testBankKey)
 	}
 
 	var (
@@ -91,7 +91,7 @@ func TestTxPool(t *testing.T) {
 	core.MustCommitGenesis(ldb, &gspec)
 	// Assemble the test environment
 	blockchain, _ := core.NewBlockChain(sdb, nil, params.TestChainConfig, ethash.NewFullFaker(), vm.Config{}, nil)
-	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), sdb, poolTestBlocks, txPoolTestChainGen)
+	gchain, _ := core.GenerateChain(params.TestChainConfig, genesis, ethash.NewFaker(), sdb, poolTestBlocksN, txPoolTestChainGen)
 	if _, err := blockchain.InsertChain(gchain); err != nil {
 		panic(err)
 	}
@@ -113,16 +113,35 @@ func TestTxPool(t *testing.T) {
 		s := sentTx(i - 1)
 		e := sentTx(i)
 		for i := s; i < e; i++ {
-			pool.Add(ctx, testTx[i])
+			pool.Add(ctx, testTxSet[i])
 			got := <-relay.send
 			exp := 1
 			if got != exp {
 				t.Errorf("relay.Send expected len = %d, got %d", exp, got)
 			}
 		}
+		if ii == len(gchain)/4 {
+			// Fuck up pool head
+			// This is an edge case that I'm not sure could really happen (hopefully not),
+			// but checking anyways. Call it sanity.
+			t.Log("Setting pool head to empty hash")
+			pool.head = common.Hash{}
+		}
 
+		if ii == len(gchain)/2 {
+			// Attempt to insert a nil header into the headerchain
+			t.Log("Inserting nil header into header chain")
+			if _, err := lightchain.InsertHeaderChain([]*types.Header{nil}, 1); err == nil {
+				t.Fatal("insert nil header error should not be errorless")
+			}
+		}
+		if ii == len(gchain)/4*3 {
+			var h *types.Header
+			t.Log("Setting pool head to a nil header", h.Hash().Hex())
+			pool.setNewHead(h)
+		}
 		if _, err := lightchain.InsertHeaderChain([]*types.Header{block.Header()}, 1); err != nil {
-			panic(err)
+			t.Fatal(err)
 		}
 
 		got := <-relay.mined