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eth, eth/downloader: detect and handle madeup hash attacks

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This commit is contained in:
Péter Szilágyi
2015-05-15 13:14:46 +03:00
parent 9ad515d2dc
commit 83226762c2
4 changed files with 111 additions and 44 deletions
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45
eth/downloader/downloader_test.go
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@ -130,8 +130,23 @@ func (dl *downloadTester) getBlock(hash common.Hash) *types.Block {
return dl.blocks[knownHash]
}
func (dl *downloadTester) getHashes(hash common.Hash) error {
dl.downloader.DeliverHashes(dl.activePeerId, dl.hashes)
// getHashes retrieves a batch of hashes for reconstructing the chain.
func (dl *downloadTester) getHashes(head common.Hash) error {
// Gather the next batch of hashes
hashes := make([]common.Hash, 0, maxHashFetch)
for i, hash := range dl.hashes {
if hash == head {
for len(hashes) < cap(hashes) && i < len(dl.hashes) {
hashes = append(hashes, dl.hashes[i])
i++
}
break
}
}
// Delay delivery a bit to allow attacks to unfold
time.Sleep(time.Millisecond)
dl.downloader.DeliverHashes(dl.activePeerId, hashes)
return nil
}
@ -166,7 +181,7 @@ func (dl *downloadTester) badBlocksPeer(id string, td *big.Int, hash common.Hash
func TestDownload(t *testing.T) {
minDesiredPeerCount = 4
blockTtl = 1 * time.Second
blockTTL = 1 * time.Second
targetBlocks := 1000
hashes := createHashes(0, targetBlocks)
@ -215,7 +230,7 @@ func TestMissing(t *testing.T) {
func TestTaking(t *testing.T) {
minDesiredPeerCount = 4
blockTtl = 1 * time.Second
blockTTL = 1 * time.Second
targetBlocks := 1000
hashes := createHashes(0, targetBlocks)
@ -256,7 +271,7 @@ func TestInactiveDownloader(t *testing.T) {
func TestCancel(t *testing.T) {
minDesiredPeerCount = 4
blockTtl = 1 * time.Second
blockTTL = 1 * time.Second
targetBlocks := 1000
hashes := createHashes(0, targetBlocks)
@ -282,7 +297,7 @@ func TestCancel(t *testing.T) {
func TestThrottling(t *testing.T) {
minDesiredPeerCount = 4
blockTtl = 1 * time.Second
blockTTL = 1 * time.Second
targetBlocks := 16 * blockCacheLimit
hashes := createHashes(0, targetBlocks)
@ -429,3 +444,21 @@ func TestInvalidHashOrderAttack(t *testing.T) {
t.Fatalf("failed to synchronise blocks: %v", err)
}
}
// Tests that if a malicious peer makes up a random hash chain and tries to push
// indefinitely, it actually gets caught with it.
func TestMadeupHashChainAttack(t *testing.T) {
blockTTL = 100 * time.Millisecond
crossCheckCycle = 25 * time.Millisecond
// Create a long chain of hashes without backing blocks
hashes := createHashes(0, 1024*blockCacheLimit)
hashes = hashes[:len(hashes)-1]
// Try and sync with the malicious node and check that it fails
tester := newTester(t, hashes, nil)
tester.newPeer("attack", big.NewInt(10000), hashes[0])
if _, err := tester.syncTake("attack", hashes[0]); err != ErrCrossCheckFailed {
t.Fatalf("synchronisation error mismatch: have %v, want %v", err, ErrCrossCheckFailed)
}
}