Bugfix: Enable ConnectBestBlock to properly report back validation problems, and ensure orphan processing (when their parents are found) cannot be used to counter-DDoS the node providing the parent

Also fix a minor typo

src/main.cpp

@@ -1250,7 +1250,6 @@ bool ConnectBestBlock(CValidationState &state) {
                 BOOST_FOREACH(CBlockIndex *pindexSwitch, vAttach) {
                     if (fRequestShutdown)
                         break;
-                    CValidationState state;
                     try {
                         if (!SetBestChain(state, pindexSwitch))
                             return false;
@@ -1405,7 +1404,7 @@ bool CTransaction::CheckInputs(CValidationState &state, CCoinsViewCache &inputs,
         }
 
         if (nValueIn < GetValueOut())
-            return state.DoS(100, error("ChecktInputs() : %s value in < value out", GetHash().ToString().substr(0,10).c_str()));
+            return state.DoS(100, error("CheckInputs() : %s value in < value out", GetHash().ToString().substr(0,10).c_str()));
 
         // Tally transaction fees
         int64 nTxFee = nValueIn - GetValueOut();
@@ -2259,7 +2258,9 @@ bool ProcessBlock(CValidationState &state, CNode* pfrom, CBlock* pblock, CDiskBl
              ++mi)
         {
             CBlock* pblockOrphan = (*mi).second;
-            if (pblockOrphan->AcceptBlock(state))
+            // Use a dummy CValidationState so someone can't setup nodes to counter-DoS based on orphan resolution (that is, feeding people an invalid block based on LegitBlockX in order to get anyone relaying LegitBlockX banned)
+            CValidationState stateDummy;
+            if (pblockOrphan->AcceptBlock(stateDummy))
                 vWorkQueue.push_back(pblockOrphan->GetHash());
             mapOrphanBlocks.erase(pblockOrphan->GetHash());
             delete pblockOrphan;
@@ -3453,8 +3454,10 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                     CDataStream(vMsg) >> tx;
                     CInv inv(MSG_TX, tx.GetHash());
                     bool fMissingInputs2 = false;
+                    // Use a dummy CValidationState so someone can't setup nodes to counter-DoS based on orphan resolution (that is, feeding people an invalid transaction based on LegitTxX in order to get anyone relaying LegitTxX banned)
+                    CValidationState stateDummy;
 
-                    if (tx.AcceptToMemoryPool(state, true, true, &fMissingInputs2))
+                    if (tx.AcceptToMemoryPool(stateDummy, true, true, &fMissingInputs2))
                     {
                         printf("   accepted orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
                         RelayTransaction(tx, inv.hash, vMsg);