Merge pull request #63 from CryptoCoderz/master

Added: In depth block scan during validation for added security

Author: CryptoCoderz

src/chainparams.cpp

@@ -113,7 +113,7 @@ class CMainParams : public CChainParams {
         nPoolMaxTransactions = 9;
         strMNenginePoolDummyAddress = "dUnVN6zz2apaoWkb5krGoBCwwo8ZD3axue";
         strDevOpsAddress = "dSCXLHTZJJqTej8ZRszZxbLrS6dDGVJhw7";
-        nEndPoWBlock = 394624;
+        nEndPoWBlock = 999999;
         nStartPoSBlock = 0;
     }
 

src/main.cpp

@@ -735,6 +735,23 @@ double CTransaction::ComputePriority(double dPriorityInputs, unsigned int nTxSiz
     return dPriorityInputs / nTxSize;
 }
 
+void CTransaction::GetMapTxInputs(MapPrevTx& mapInputs) const
+{
+    // Load TX inputs
+    CTxDB txdb("r");
+    map<uint256, CTxIndex> mapUnused;
+    bool fInvalid = false;
+    // Ensure we can fetch inputs
+    if (!this->FetchInputs(txdb, mapUnused, false, false, mapInputs, fInvalid))
+    {
+        if (fInvalid)
+        {
+            LogPrintf("Invalid TX attempted to set in GetMapTXInputs\n");
+            return;
+        }
+    }
+}
+
 bool CTransaction::CheckTransaction() const
 {
     // Basic checks that don't depend on any context
@@ -917,7 +934,11 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CTransaction &tx, bool fLimitFree,
                           error("AcceptToMemoryPool : too many sigops %s, %d > %d",
                                 hash.ToString(), nSigOps, MAX_TX_SIGOPS));
 
-        int64_t nFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
+        int64_t nFees = tx.GetValueMapIn(mapInputs)-tx.GetValueOut();
+        if (tx.GetValueMapIn(mapInputs) < tx.GetValueOut()) {
+            LogPrintf("AcceptToMemoryPool : tx input is less that output\n");
+            return tx.DoS(100, error("AcceptToMemoryPool : tx input is less that output"));
+        }
         unsigned int nSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 
         // Don't accept it if it can't get into a block
@@ -1079,7 +1100,11 @@ bool AcceptableInputs(CTxMemPool& pool, const CTransaction &txo, bool fLimitFree
                           error("AcceptableInputs : too many sigops %s, %d > %d",
                                 hash.ToString(), nSigOps, MAX_TX_SIGOPS));
 
-        int64_t nFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
+        int64_t nFees = tx.GetValueMapIn(mapInputs)-tx.GetValueOut();
+        if (tx.GetValueMapIn(mapInputs) < tx.GetValueOut()) {
+            LogPrintf("AcceptableInputs : tx input is less that output\n");
+            return error("AcceptableInputs : tx input is less than output");
+        }
         unsigned int nSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
         int64_t txMinFee = GetMinFee(tx, nSize, true, GMF_RELAY);
 
@@ -1568,7 +1593,7 @@ bool CTransaction::DisconnectInputs(CTxDB& txdb)
 
 
 bool CTransaction::FetchInputs(CTxDB& txdb, const map<uint256, CTxIndex>& mapTestPool,
-                               bool fBlock, bool fMiner, MapPrevTx& inputsRet, bool& fInvalid)
+                               bool fBlock, bool fMiner, MapPrevTx& inputsRet, bool& fInvalid) const
 {
     // FetchInputs can return false either because we just haven't seen some inputs
     // (in which case the transaction should be stored as an orphan)
@@ -1651,7 +1676,7 @@ const CTxOut& CTransaction::GetOutputFor(const CTxIn& input, const MapPrevTx& in
     return txPrev.vout[input.prevout.n];
 }
 
-int64_t CTransaction::GetValueIn(const MapPrevTx& inputs) const
+int64_t CTransaction::GetValueMapIn(const MapPrevTx& inputs) const
 {
     if (IsCoinBase())
         return 0;
@@ -1972,12 +1997,17 @@ bool CBlock::ConnectBlock(CTxDB& txdb, CBlockIndex* pindex, bool fJustCheck)
             if (nSigOps > MAX_BLOCK_SIGOPS)
                 return DoS(100, error("ConnectBlock() : too many sigops"));
 
-            int64_t nTxValueIn = tx.GetValueIn(mapInputs);
+            int64_t nTxValueIn = tx.GetValueMapIn(mapInputs);
             int64_t nTxValueOut = tx.GetValueOut();
             nValueIn += nTxValueIn;
             nValueOut += nTxValueOut;
-            if (!tx.IsCoinStake())
+            if (!tx.IsCoinStake()) {
                 nFees += nTxValueIn - nTxValueOut;
+                if (nTxValueIn < nTxValueOut) {
+                    LogPrintf("ConnectBlock : block contains a tx input that is less that output\n");
+                    return false;
+                }
+            }
             if (tx.IsCoinStake())
                 nStakeReward = nTxValueOut - nTxValueIn;
 
@@ -2912,10 +2942,28 @@ bool CBlock::AcceptBlock()
     if (GetBlockTime() <= pindexPrev->GetPastTimeLimit() || FutureDrift(GetBlockTime()) < pindexPrev->GetBlockTime())
         return error("AcceptBlock() : block's timestamp is too early");
 
+    // Set logged values
+    CAmount tx_inputs_values = 0;
+    CAmount tx_outputs_values = 0;
+    CAmount tx_threshold = (300 * COIN);
     // Check that all transactions are finalized
     BOOST_FOREACH(const CTransaction& tx, vtx)
-        if (!IsFinalTx(tx, nHeight, GetBlockTime()))
+    {
+        if (!IsFinalTx(tx, nHeight, GetBlockTime())) {
             return DoS(10, error("AcceptBlock() : contains a non-final transaction"));
+        }
+        // Log inputs/output values
+        MapPrevTx mapInputs;
+        tx.GetMapTxInputs(mapInputs);
+        tx_inputs_values += tx.GetValueMapIn(mapInputs);
+        tx_outputs_values += tx.GetValueOut();
+    }
+
+    // Ensure input/output sanity of transactions in the block
+    if((tx_inputs_values + tx_threshold) < tx_outputs_values)
+    {
+        return DoS(100, error("AcceptBlock() : block contains a tx input that is less that output"));
+    }
 
     // Check that the block chain matches the known block chain up to a checkpoint
     if (!Checkpoints::CheckHardened(nHeight, hash))

src/main.h

@@ -328,6 +328,8 @@ class CTransaction
         }
         return nValueOut;
     }
+    // Map TX inputs for scanning
+    void GetMapTxInputs(MapPrevTx &mapInputs) const;
 
     /** Amount of bitcoins coming in to this transaction
         Note that lightweight clients may not know anything besides the hash of previous transactions,
@@ -337,7 +339,7 @@ class CTransaction
         @return Sum of value of all inputs (scriptSigs)
         @see CTransaction::FetchInputs
      */
-    int64_t GetValueIn(const MapPrevTx& mapInputs) const;
+    int64_t GetValueMapIn(const MapPrevTx& mapInputs) const;
 
     bool ReadFromDisk(CDiskTxPos pos, FILE** pfileRet=NULL)
     {
@@ -416,7 +418,7 @@ class CTransaction
      @return    Returns true if all inputs are in txdb or mapTestPool
      */
     bool FetchInputs(CTxDB& txdb, const std::map<uint256, CTxIndex>& mapTestPool,
-                     bool fBlock, bool fMiner, MapPrevTx& inputsRet, bool& fInvalid);
+                     bool fBlock, bool fMiner, MapPrevTx& inputsRet, bool& fInvalid) const;
 
     /** Sanity check previous transactions, then, if all checks succeed,
         mark them as spent by this transaction.

src/miner.cpp

@@ -316,7 +316,7 @@ CBlock* CreateNewBlock(CReserveKey& reservekey, bool fProofOfStake, int64_t* pFe
             if (!tx.FetchInputs(txdb, mapTestPoolTmp, false, true, mapInputs, fInvalid))
                 continue;
 
-            int64_t nTxFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
+            int64_t nTxFees = tx.GetValueMapIn(mapInputs)-tx.GetValueOut();
 
             nTxSigOps += GetP2SHSigOpCount(tx, mapInputs);
             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)

src/rpcmining.cpp

@@ -623,7 +623,7 @@ Value getblocktemplate(const Array& params, bool fHelp)
         bool fInvalid = false;
         if (tx.FetchInputs(txdb, mapUnused, false, false, mapInputs, fInvalid))
         {
-            entry.push_back(Pair("fee", (int64_t)(tx.GetValueIn(mapInputs) - tx.GetValueOut())));
+            entry.push_back(Pair("fee", (int64_t)(tx.GetValueMapIn(mapInputs) - tx.GetValueOut())));
 
             Array deps;
             BOOST_FOREACH (MapPrevTx::value_type& inp, mapInputs)

src/velocity.cpp

@@ -85,7 +85,7 @@ bool Velocity(CBlockIndex* prevBlock, CBlock* block)
         BOOST_FOREACH(const CTransaction& tx, block->vtx)
         {
             TXvalue = tx.GetValueOut();
-            TXinput = tx.GetValueIn(mapInputs);
+            TXinput = tx.GetValueMapIn(mapInputs);
             TXfee = TXinput - TXvalue;
             TXcount = block->vtx.size();
             // TXlogic = GetPrevAccountBalance - TXinput;
@@ -169,7 +169,7 @@ bool Velocity(CBlockIndex* prevBlock, CBlock* block)
             {
                 TXcount = block->vtx.size();
                 TXvalue = tx.GetValueOut();
-                TXinput = tx.GetValueIn(mapInputs);
+                TXinput = tx.GetValueMapIn(mapInputs);
                 TXfee = TXinput - TXvalue;
                 if(TXfee > devopsPayment){
                     TXnetfee = TXfee - devopsPayment;