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Don't process unrequested, low-work blocks

A peer could try to waste our resources by sending us unrequested blocks with
low work, eg to fill up our disk.  Since
e2652002b6 we no longer request blocks until we
know we're on a chain with more than nMinimumChainWork (our anti-DoS
threshold), but we would still process unrequested blocks that had more work
than our tip.  This commit fixes that behavior.

Github-Pull: #11458
Rebased-From: ce8cd7a7da
0.15
Suhas Daftuar 7 years ago committed by MarcoFalke
parent
commit
3acec38781
  1. 6
      src/validation.cpp

6
src/validation.cpp

@ -3120,6 +3120,12 @@ static bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CValidation @@ -3120,6 +3120,12 @@ static bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CValidation
if (pindex->nTx != 0) return true; // This is a previously-processed block that was pruned
if (!fHasMoreWork) return true; // Don't process less-work chains
if (fTooFarAhead) return true; // Block height is too high
// Protect against DoS attacks from low-work chains.
// If our tip is behind, a peer could try to send us
// low-work blocks on a fake chain that we would never
// request; don't process these.
if (pindex->nChainWork < nMinimumChainWork) return true;
}
if (fNewBlock) *fNewBlock = true;

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