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Avoid leaking the prune height through getdata (fingerprinting countermeasure)

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Jonas Schnelli 2017-08-11 20:59:24 +02:00
parent 27df193efd
commit bd09416524
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1 changed files with 10 additions and 0 deletions
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10
src/net_processing.cpp
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@ -1091,6 +1091,16 @@ void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParam
pfrom->fDisconnect = true;
send = false;
}
// Avoid leaking prune-height by never sending blocks below the NODE_NETWORK_LIMITED threshold
if (send && !pfrom->fWhitelisted && (
(((pfrom->GetLocalServices() & NODE_NETWORK_LIMITED) == NODE_NETWORK_LIMITED) && ((pfrom->GetLocalServices() & NODE_NETWORK) != NODE_NETWORK) && (chainActive.Tip()->nHeight - mi->second->nHeight > (int)NODE_NETWORK_LIMITED_MIN_BLOCKS + 2 /* add two blocks buffer extension for possible races */) )
)) {
LogPrint(BCLog::NET, "Ignore block request below NODE_NETWORK_LIMITED threshold from peer=%d\n", pfrom->GetId());
//disconnect node and prevent it from stalling (would otherwise wait for the missing block)
pfrom->fDisconnect = true;
send = false;
}
// Pruned nodes may have deleted the block, so check whether
// it's available before trying to send.
if (send && (mi->second->nStatus & BLOCK_HAVE_DATA))