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authorMatt Corallo <git@bluematt.me>2017-06-05 20:46:23 -0400
committerMatt Corallo <git@bluematt.me>2017-06-22 12:21:09 -0400
commitb014668e27b496bd6ad30985294f3d6971311910 (patch)
tree9236fe0b456f308f413791efe72fa6b9733f7d02 /src/validation.cpp
parenteada04e778435574198b5778bf6ccc72cfcba7be (diff)
Add CheckInputs wrapper CCoinsViewMemPool -> non-consensus-critical
This wraps CheckInputs in ATMP's cache-inputs call to check that each scriptPubKey the CCoinsViewCache provides is the one which was committed to by the input's transaction hash.
Diffstat (limited to 'src/validation.cpp')
-rw-r--r--src/validation.cpp38
1 files changed, 37 insertions, 1 deletions
diff --git a/src/validation.cpp b/src/validation.cpp
index 621077bcba..463c16c11f 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -399,6 +399,42 @@ void UpdateMempoolForReorg(DisconnectedBlockTransactions &disconnectpool, bool f
LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
}
+// Used to avoid mempool polluting consensus critical paths if CCoinsViewMempool
+// were somehow broken and returning the wrong scriptPubKeys
+static bool CheckInputsFromMempoolAndCache(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &view, CTxMemPool& pool,
+ unsigned int flags, bool cacheSigStore, PrecomputedTransactionData& txdata) {
+ AssertLockHeld(cs_main);
+
+ // pool.cs should be locked already, but go ahead and re-take the lock here
+ // to enforce that mempool doesn't change between when we check the view
+ // and when we actually call through to CheckInputs
+ LOCK(pool.cs);
+
+ assert(!tx.IsCoinBase());
+ for (const CTxIn& txin : tx.vin) {
+ const Coin& coin = view.AccessCoin(txin.prevout);
+
+ // At this point we haven't actually checked if the coins are all
+ // available (or shouldn't assume we have, since CheckInputs does).
+ // So we just return failure if the inputs are not available here,
+ // and then only have to check equivalence for available inputs.
+ if (coin.IsSpent()) return false;
+
+ const CTransactionRef& txFrom = pool.get(txin.prevout.hash);
+ if (txFrom) {
+ assert(txFrom->GetHash() == txin.prevout.hash);
+ assert(txFrom->vout.size() > txin.prevout.n);
+ assert(txFrom->vout[txin.prevout.n] == coin.out);
+ } else {
+ const Coin& coinFromDisk = pcoinsTip->AccessCoin(txin.prevout);
+ assert(!coinFromDisk.IsSpent());
+ assert(coinFromDisk.out == coin.out);
+ }
+ }
+
+ return CheckInputs(tx, state, view, true, flags, cacheSigStore, true, txdata);
+}
+
static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool& pool, CValidationState& state, const CTransactionRef& ptx, bool fLimitFree,
bool* pfMissingInputs, int64_t nAcceptTime, std::list<CTransactionRef>* plTxnReplaced,
bool fOverrideMempoolLimit, const CAmount& nAbsurdFee, std::vector<COutPoint>& coins_to_uncache)
@@ -782,7 +818,7 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
// invalid blocks (using TestBlockValidity), however allowing such
// transactions into the mempool can be exploited as a DoS attack.
unsigned int currentBlockScriptVerifyFlags = GetBlockScriptFlags(chainActive.Tip(), Params().GetConsensus());
- if (!CheckInputs(tx, state, view, true, currentBlockScriptVerifyFlags, true, true, txdata))
+ if (!CheckInputsFromMempoolAndCache(tx, state, view, pool, currentBlockScriptVerifyFlags, true, txdata))
{
// If we're using promiscuousmempoolflags, we may hit this normally
// Check if current block has some flags that scriptVerifyFlags