core: more tests for sidechain import, fixes #19105 (#19113)

* blockchain: more tests for sidechain import, fixes #19105

* core/blockchain: rework import of pruned canon blocks and canon-prepended sidechains

* core/blockchain: minor clarity change

* core/blockchain: remove unused method
This commit is contained in:
Martin Holst Swende 2019-02-21 11:36:49 +01:00 committed by Péter Szilágyi
parent 628a0bde3f
commit 8577b5b020
2 changed files with 115 additions and 20 deletions

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@ -1084,15 +1084,21 @@ func (bc *BlockChain) InsertChain(chain types.Blocks) (int, error) {
if len(chain) == 0 {
return 0, nil
}
// Remove already known canon-blocks
var (
block, prev *types.Block
)
// Do a sanity check that the provided chain is actually ordered and linked
for i := 1; i < len(chain); i++ {
if chain[i].NumberU64() != chain[i-1].NumberU64()+1 || chain[i].ParentHash() != chain[i-1].Hash() {
block = chain[i]
prev = chain[i-1]
if block.NumberU64() != prev.NumberU64()+1 || block.ParentHash() != prev.Hash() {
// Chain broke ancestry, log a message (programming error) and skip insertion
log.Error("Non contiguous block insert", "number", chain[i].Number(), "hash", chain[i].Hash(),
"parent", chain[i].ParentHash(), "prevnumber", chain[i-1].Number(), "prevhash", chain[i-1].Hash())
log.Error("Non contiguous block insert", "number", block.Number(), "hash", block.Hash(),
"parent", block.ParentHash(), "prevnumber", prev.Number(), "prevhash", prev.Hash())
return 0, fmt.Errorf("non contiguous insert: item %d is #%d [%x…], item %d is #%d [%x…] (parent [%x…])", i-1, chain[i-1].NumberU64(),
chain[i-1].Hash().Bytes()[:4], i, chain[i].NumberU64(), chain[i].Hash().Bytes()[:4], chain[i].ParentHash().Bytes()[:4])
return 0, fmt.Errorf("non contiguous insert: item %d is #%d [%x…], item %d is #%d [%x…] (parent [%x…])", i-1, prev.NumberU64(),
prev.Hash().Bytes()[:4], i, block.NumberU64(), block.Hash().Bytes()[:4], block.ParentHash().Bytes()[:4])
}
}
// Pre-checks passed, start the full block imports
@ -1146,6 +1152,22 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, []
it := newInsertIterator(chain, results, bc.Validator())
block, err := it.next()
// Left-trim all the known blocks
if err == ErrKnownBlock {
// First block (and state) is known
// 1. We did a roll-back, and should now do a re-import
// 2. The block is stored as a sidechain, and is lying about it's stateroot, and passes a stateroot
// from the canonical chain, which has not been verified.
// Skip all known blocks that are behind us
current := bc.CurrentBlock().NumberU64()
for block != nil && err == ErrKnownBlock && current >= block.NumberU64() {
stats.ignored++
block, err = it.next()
}
// Falls through to the block import
}
switch {
// First block is pruned, insert as sidechain and reorg only if TD grows enough
case err == consensus.ErrPrunedAncestor:
@ -1165,20 +1187,6 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, []
// If there are any still remaining, mark as ignored
return it.index, events, coalescedLogs, err
// First block (and state) is known
// 1. We did a roll-back, and should now do a re-import
// 2. The block is stored as a sidechain, and is lying about it's stateroot, and passes a stateroot
// from the canonical chain, which has not been verified.
case err == ErrKnownBlock:
// Skip all known blocks that behind us
current := bc.CurrentBlock().NumberU64()
for block != nil && err == ErrKnownBlock && current >= block.NumberU64() {
stats.ignored++
block, err = it.next()
}
// Falls through to the block import
// Some other error occurred, abort
case err != nil:
stats.ignored += len(it.chain)
@ -1304,7 +1312,12 @@ func (bc *BlockChain) insertSidechain(block *types.Block, it *insertIterator) (i
for ; block != nil && (err == consensus.ErrPrunedAncestor); block, err = it.next() {
// Check the canonical state root for that number
if number := block.NumberU64(); current.NumberU64() >= number {
if canonical := bc.GetBlockByNumber(number); canonical != nil && canonical.Root() == block.Root() {
canonical := bc.GetBlockByNumber(number)
if canonical != nil && canonical.Hash() == block.Hash() {
// Not a sidechain block, this is a re-import of a canon block which has it's state pruned
continue
}
if canonical != nil && canonical.Root() == block.Root() {
// This is most likely a shadow-state attack. When a fork is imported into the
// database, and it eventually reaches a block height which is not pruned, we
// just found that the state already exist! This means that the sidechain block

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@ -1521,3 +1521,85 @@ func TestLowDiffLongChain(t *testing.T) {
header = chain.GetHeader(header.ParentHash, number-1)
}
}
// Tests that importing a sidechain (S), where
// - S is sidechain, containing blocks [Sn...Sm]
// - C is canon chain, containing blocks [G..Cn..Cm]
// - A common ancestor is placed at prune-point + blocksBetweenCommonAncestorAndPruneblock
// - The sidechain S is prepended with numCanonBlocksInSidechain blocks from the canon chain
func testSideImport(t *testing.T, numCanonBlocksInSidechain, blocksBetweenCommonAncestorAndPruneblock int) {
// Generate a canonical chain to act as the main dataset
engine := ethash.NewFaker()
db := ethdb.NewMemDatabase()
genesis := new(Genesis).MustCommit(db)
// Generate and import the canonical chain
blocks, _ := GenerateChain(params.TestChainConfig, genesis, engine, db, 2*triesInMemory, nil)
diskdb := ethdb.NewMemDatabase()
new(Genesis).MustCommit(diskdb)
chain, err := NewBlockChain(diskdb, nil, params.TestChainConfig, engine, vm.Config{}, nil)
if err != nil {
t.Fatalf("failed to create tester chain: %v", err)
}
if n, err := chain.InsertChain(blocks); err != nil {
t.Fatalf("block %d: failed to insert into chain: %v", n, err)
}
lastPrunedIndex := len(blocks) - triesInMemory - 1
lastPrunedBlock := blocks[lastPrunedIndex]
firstNonPrunedBlock := blocks[len(blocks)-triesInMemory]
// Verify pruning of lastPrunedBlock
if chain.HasBlockAndState(lastPrunedBlock.Hash(), lastPrunedBlock.NumberU64()) {
t.Errorf("Block %d not pruned", lastPrunedBlock.NumberU64())
}
// Verify firstNonPrunedBlock is not pruned
if !chain.HasBlockAndState(firstNonPrunedBlock.Hash(), firstNonPrunedBlock.NumberU64()) {
t.Errorf("Block %d pruned", firstNonPrunedBlock.NumberU64())
}
// Generate the sidechain
// First block should be a known block, block after should be a pruned block. So
// canon(pruned), side, side...
// Generate fork chain, make it longer than canon
parentIndex := lastPrunedIndex + blocksBetweenCommonAncestorAndPruneblock
parent := blocks[parentIndex]
fork, _ := GenerateChain(params.TestChainConfig, parent, engine, db, 2*triesInMemory, func(i int, b *BlockGen) {
b.SetCoinbase(common.Address{2})
})
// Prepend the parent(s)
var sidechain []*types.Block
for i := numCanonBlocksInSidechain; i > 0; i-- {
sidechain = append(sidechain, blocks[parentIndex+1-i])
}
sidechain = append(sidechain, fork...)
_, err = chain.InsertChain(sidechain)
if err != nil {
t.Errorf("Got error, %v", err)
}
head := chain.CurrentBlock()
if got := fork[len(fork)-1].Hash(); got != head.Hash() {
t.Fatalf("head wrong, expected %x got %x", head.Hash(), got)
}
}
// Tests that importing a sidechain (S), where
// - S is sidechain, containing blocks [Sn...Sm]
// - C is canon chain, containing blocks [G..Cn..Cm]
// - The common ancestor Cc is pruned
// - The first block in S: Sn, is == Cn
// That is: the sidechain for import contains some blocks already present in canon chain.
// So the blocks are
// [ Cn, Cn+1, Cc, Sn+3 ... Sm]
// ^ ^ ^ pruned
func TestPrunedImportSide(t *testing.T) {
//glogger := log.NewGlogHandler(log.StreamHandler(os.Stdout, log.TerminalFormat(false)))
//glogger.Verbosity(3)
//log.Root().SetHandler(log.Handler(glogger))
testSideImport(t, 3, 3)
testSideImport(t, 3, -3)
testSideImport(t, 10, 0)
testSideImport(t, 1, 10)
testSideImport(t, 1, -10)
}