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| author | Mark Friedenbach <mark@friedenbach.org> | 2015-05-22 14:49:50 -0700 |
|---|---|---|
| committer | Mark Friedenbach <mark@friedenbach.org> | 2015-05-27 14:03:11 -0700 |
| commit | ef8dfe41d1eba0de6d6554e25e658169f97313b5 (patch) | |
| tree | fb269c424ccf2fe715c639df712dba7ae1cf34dc /src | |
| parent | ce56f5621a94dcc2159ebe57e43da727eab18e6c (diff) | |
| download | bitcoin-ef8dfe41d1eba0de6d6554e25e658169f97313b5.tar.xz | |
Prevent block.nTime from decreasing
Under some circumstances it is possible for there to be a significant,
discontinuous jump in a node's clock value. On mining nodes, this can
result in block templates which are no longer valid due to time-based
nLockTime constraints. UpdateTime() is modified so that it will never
decrease a block's nLockTime, thereby preventing such invalidations.
Diffstat (limited to 'src')
| -rw-r--r-- | src/miner.cpp | 17 | ||||
| -rw-r--r-- | src/miner.h | 2 |
2 files changed, 14 insertions, 5 deletions
diff --git a/src/miner.cpp b/src/miner.cpp index 7a57b42e30..693e04dec2 100644 --- a/src/miner.cpp +++ b/src/miner.cpp @@ -81,13 +81,19 @@ public: } }; -void UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev) +int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev) { - pblock->nTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime()); + int64_t nOldTime = pblock->nTime; + int64_t nNewTime = std::max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime()); + + if (nOldTime < nNewTime) + pblock->nTime = nNewTime; // Updating time can change work required on testnet: if (consensusParams.fPowAllowMinDifficultyBlocks) pblock->nBits = GetNextWorkRequired(pindexPrev, pblock, consensusParams); + + return nNewTime - nOldTime; } CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn) @@ -138,6 +144,7 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn) LOCK2(cs_main, mempool.cs); CBlockIndex* pindexPrev = chainActive.Tip(); const int nHeight = pindexPrev->nHeight + 1; + pblock->nTime = GetAdjustedTime(); CCoinsViewCache view(pcoinsTip); // Priority order to process transactions @@ -152,7 +159,7 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn) mi != mempool.mapTx.end(); ++mi) { const CTransaction& tx = mi->second.GetTx(); - if (tx.IsCoinBase() || !IsFinalTx(tx, nHeight)) + if (tx.IsCoinBase() || !IsFinalTx(tx, nHeight, pblock->nTime)) continue; COrphan* porphan = NULL; @@ -529,7 +536,9 @@ void static BitcoinMiner(CWallet *pwallet) break; // Update nTime every few seconds - UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev); + if (UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev) < 0) + break; // Recreate the block if the clock has run backwards, + // so that we can use the correct time. if (chainparams.GetConsensus().fPowAllowMinDifficultyBlocks) { // Changing pblock->nTime can change work required on testnet: diff --git a/src/miner.h b/src/miner.h index 96a6b70ecd..d46f4b1f2d 100644 --- a/src/miner.h +++ b/src/miner.h @@ -30,6 +30,6 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn); CBlockTemplate* CreateNewBlockWithKey(CReserveKey& reservekey); /** Modify the extranonce in a block */ void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce); -void UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev); +int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev); #endif // BITCOIN_MINER_H |