From 2a220540258487709b77eded1e82e3839cfd5aab Mon Sep 17 00:00:00 2001 From: Gregory Maxwell Date: Mon, 9 Sep 2013 02:11:11 -0700 Subject: [PATCH] Longer term workaround for chainstate corruption from negative versions. This also makes negative transaction versions non-standard. This avoids an issue triggered in Bitcoin block 256818 where transactions with negative version numbers were incorrectly serialized into the UTXO set. On restart nodes detect the inconsistency and refuse to start so long as a block with these transactions is inside the self-consistency check window, logging "coin database inconsistencies found". The software recommends reindexing, but reindexing does not correct the problem. This should be fixed by changing the chainstate serialization, but working around it seems harmless for now because the version is not used by any network rule currently. A patch free workaround is to start with -checklevel=2 which skips the consistency checks, but the IsStandard change is important for miners in order to protect unpatched nodes. --- src/main.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/main.cpp b/src/main.cpp index 06fea7446..972ea3de0 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -362,7 +362,7 @@ bool CTxOut::IsDust() const bool CTransaction::IsStandard(string& strReason) const { - if (nVersion > CTransaction::CURRENT_VERSION) { + if (nVersion > CTransaction::CURRENT_VERSION || nVersion < 1) { strReason = "version"; return false; } @@ -1513,6 +1513,11 @@ bool CBlock::DisconnectBlock(CValidationState &state, CBlockIndex *pindex, CCoin CCoins &outs = view.GetCoins(hash); CCoins outsBlock = CCoins(tx, pindex->nHeight); + // The CCoins serialization does not serialize negative numbers. + // No network rules currently depend on the version here, so an inconsistency is harmless + // but it must be corrected before txout nversion ever influences a network rule. + if (outsBlock.nVersion < 0) + outs.nVersion = outsBlock.nVersion; if (outs != outsBlock) fClean = fClean && error("DisconnectBlock() : added transaction mismatch? database corrupted");