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eth/downloader: circumvent hash reordering attacks

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This commit is contained in:
Péter Szilágyi
2015-05-15 11:58:37 +03:00
parent bcc2980179
commit 72411eb24c
3 changed files with 88 additions and 49 deletions
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36
eth/downloader/downloader.go
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@ -23,20 +23,20 @@ var (
minDesiredPeerCount = 5 // Amount of peers desired to start syncing
blockTtl = 20 * time.Second // The amount of time it takes for a block request to time out
errLowTd = errors.New("peer's TD is too low")
ErrBusy = errors.New("busy")
errUnknownPeer = errors.New("peer's unknown or unhealthy")
ErrBadPeer = errors.New("action from bad peer ignored")
errNoPeers = errors.New("no peers to keep download active")
ErrPendingQueue = errors.New("pending items in queue")
ErrTimeout = errors.New("timeout")
errEmptyHashSet = errors.New("empty hash set by peer")
errPeersUnavailable = errors.New("no peers available or all peers tried for block download process")
errAlreadyInPool = errors.New("hash already in pool")
errBlockNumberOverflow = errors.New("received block which overflows")
errCancelHashFetch = errors.New("hash fetching cancelled (requested)")
errCancelBlockFetch = errors.New("block downloading cancelled (requested)")
errNoSyncActive = errors.New("no sync active")
errLowTd = errors.New("peer's TD is too low")
ErrBusy = errors.New("busy")
errUnknownPeer = errors.New("peer's unknown or unhealthy")
ErrBadPeer = errors.New("action from bad peer ignored")
errNoPeers = errors.New("no peers to keep download active")
ErrPendingQueue = errors.New("pending items in queue")
ErrTimeout = errors.New("timeout")
errEmptyHashSet = errors.New("empty hash set by peer")
errPeersUnavailable = errors.New("no peers available or all peers tried for block download process")
errAlreadyInPool = errors.New("hash already in pool")
ErrInvalidChain = errors.New("retrieved hash chain is invalid")
errCancelHashFetch = errors.New("hash fetching cancelled (requested)")
errCancelBlockFetch = errors.New("block downloading cancelled (requested)")
errNoSyncActive = errors.New("no sync active")
)
type hashCheckFn func(common.Hash) bool
@ -334,8 +334,14 @@ out:
// If the peer was previously banned and failed to deliver it's pack
// in a reasonable time frame, ignore it's message.
if peer := d.peers.Peer(blockPack.peerId); peer != nil {
// Deliver the received chunk of blocks, but drop the peer if invalid
// Deliver the received chunk of blocks
if err := d.queue.Deliver(blockPack.peerId, blockPack.blocks); err != nil {
if err == ErrInvalidChain {
// The hash chain is invalid (blocks are not ordered properly), abort
d.queue.Reset()
return err
}
// Peer did deliver, but some blocks were off, penalize
glog.V(logger.Debug).Infof("Failed delivery for peer %s: %v\n", blockPack.peerId, err)
peer.Demote()
break