Fake stake patch - 4.0

src/main.cpp

@@ -55,6 +55,7 @@ CCriticalSection cs_main;
 BlockMap mapBlockIndex;
 map<uint256, uint256> mapProofOfStake;
 set<pair<COutPoint, unsigned int> > setStakeSeen;
+ map<COutPoint, int> mapStakeSpent;
 map<unsigned int, unsigned int> mapHashedBlocks;
 CChain chainActive;
 CBlockIndex* pindexBestHeader = NULL;
@@ -1970,6 +1971,10 @@ bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex
                 if (coins->vout.size() < out.n + 1)
                     coins->vout.resize(out.n + 1);
                 coins->vout[out.n] = undo.txout;
+
+                // erase the spent input
+                if(IsSporkActive(SPORK_19_FAKE_STAKE_FIX) && block.GetBlockTime() >= GetSporkValue(SPORK_19_FAKE_STAKE_FIX))
+                    mapStakeSpent.erase(out);
             }
         }
     }
@@ -2203,6 +2208,28 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
         if (!pblocktree->WriteTxIndex(vPos))
             return state.Abort("Failed to write transaction index");
 
+    if(IsSporkActive(SPORK_19_FAKE_STAKE_FIX) && block.GetBlockTime() >= GetSporkValue(SPORK_19_FAKE_STAKE_FIX)){
+        // add new entries
+        for (const CTransaction tx:block.vtx) {
+            if (tx.IsCoinBase())
+                continue;
+            for (const CTxIn in: tx.vin) {
+                LogPrint("map", "mapStakeSpent: Insert %s | %u\n", in.prevout.ToString(), pindex->nHeight);
+                mapStakeSpent.insert(std::make_pair(in.prevout, pindex->nHeight));
+            }
+        }
+
+        // delete old entries
+        for (auto it = mapStakeSpent.begin(); it != mapStakeSpent.end();) {
+            if (it->second < pindex->nHeight - Params().MaxReorganizationDepth()) {
+                LogPrint("map", "mapStakeSpent: Erase %s | %u\n", it->first.ToString(), it->second);
+                it = mapStakeSpent.erase(it);
+            } else {
+                it++;
+            }
+        }
+    }
+
     // add this block to the view's block chain
     view.SetBestBlock(pindex->GetBlockHash());
 
@@ -3332,6 +3359,57 @@ bool AcceptBlock(CBlock& block, CValidationState& state, CBlockIndex** ppindex,
 
     int nHeight = pindex->nHeight;
 
+    if(IsSporkActive(SPORK_19_FAKE_STAKE_FIX) && block.GetBlockTime() >= GetSporkValue(SPORK_19_FAKE_STAKE_FIX)) {
+
+        if (block.IsProofOfStake()) {
+            LOCK(cs_main);
+
+            CCoinsViewCache coins(pcoinsTip);
+
+            if (!coins.HaveInputs(block.vtx[1])) {
+                // the inputs are spent at the chain tip so we should look at the recently spent outputs
+
+                for (CTxIn in : block.vtx[1].vin) {
+                    auto it = mapStakeSpent.find(in.prevout);
+                    if (it == mapStakeSpent.end()) {
+                        return false;
+                    }
+                    if (it->second <= pindexPrev->nHeight) {
+                        return false;
+                    }
+                }
+            }
+
+            // if this is on a fork
+            if (!chainActive.Contains(pindexPrev) && pindexPrev != NULL) {
+                // start at the block we're adding on to
+                CBlockIndex *last = pindexPrev;
+
+                //while that block is not on the main chain
+                while (!chainActive.Contains(last) && pindexPrev != NULL) {
+                    CBlock bl;
+                    ReadBlockFromDisk(bl, last);
+                    // loop through every spent input from said block
+                    for (CTransaction t: bl.vtx) {
+                        for (CTxIn in: t.vin) {
+                            // loop through every spent input in the staking transaction of the new block
+                            for (CTxIn stakeIn: block.vtx[1].vin) {
+                                // if they spend the same input
+                                if (stakeIn.prevout == in.prevout) {
+                                    //reject the block
+                                    return false;
+                                }
+                            }
+                        }
+                    }
+
+                    // go to the parent block
+                    last = pindexPrev->pprev;
+                }
+            }
+        }
+    }
+
     // Write block to history file
     try {
         unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);

src/spork.cpp

@@ -137,6 +137,7 @@ int64_t GetSporkValue(int nSporkID)
         if (nSporkID == SPORK_16_MN_WINNER_MINIMUM_AGE) r = SPORK_16_MN_WINNER_MINIMUM_AGE_DEFAULT;
         if (nSporkID == SPORK_17_PROPOSAL_VETO) r = SPORK_17_PROPOSAL_VETO_DEFAULT; 
         if (nSporkID == SPORK_18_KILL_STRAGGLERS) r = SPORK_18_KILL_STRAGGLERS_DEFAULT; 
+        if (nSporkID == SPORK_19_FAKE_STAKE_FIX) r = SPORK_19_FAKE_STAKE_FIX_DEFAULT; 
 
         if (r == -1) LogPrintf("GetSpork::Unknown Spork %d\n", nSporkID);
     }
@@ -287,6 +288,7 @@ int CSporkManager::GetSporkIDByName(std::string strName)
     if (strName == "SPORK_16_MN_WINNER_MINIMUM_AGE") return SPORK_16_MN_WINNER_MINIMUM_AGE;
     if (strName == "SPORK_17_PROPOSAL_VETO") return SPORK_17_PROPOSAL_VETO;
     if (strName == "SPORK_18_KILL_STRAGGLERS") return SPORK_18_KILL_STRAGGLERS;
+    if (strName == "SPORK_19_FAKE_STAKE_FIX") return SPORK_19_FAKE_STAKE_FIX;
 
     return -1;
 }
@@ -308,6 +310,7 @@ std::string CSporkManager::GetSporkNameByID(int id)
     if (id == SPORK_16_MN_WINNER_MINIMUM_AGE) return "SPORK_16_MN_WINNER_MINIMUM_AGE";
     if (id == SPORK_17_PROPOSAL_VETO) return "SPORK_17_PROPOSAL_VETO";
     if (id == SPORK_18_KILL_STRAGGLERS) return "SPORK_18_KILL_STRAGGLERS";
+    if (id == SPORK_19_FAKE_STAKE_FIX) return "SPORK_19_FAKE_STAKE_FIX";
 
     return "Unknown";
 }

src/spork.h

@@ -26,7 +26,7 @@ using namespace boost;
     - This would result in old clients getting confused about which spork is for what
 */
 #define SPORK_START 10001
-#define SPORK_END 10017
+#define SPORK_END 10018
 
 #define SPORK_2_SWIFTTX 10001
 #define SPORK_3_SWIFTTX_BLOCK_FILTERING 10002
@@ -43,6 +43,7 @@ using namespace boost;
 #define SPORK_16_MN_WINNER_MINIMUM_AGE 10015
 #define SPORK_17_PROPOSAL_VETO 10016
 #define SPORK_18_KILL_STRAGGLERS 10017
+#define SPORK_19_FAKE_STAKE_FIX 10018
 
 #define SPORK_2_SWIFTTX_DEFAULT 978307200                         //2001-1-1
 #define SPORK_3_SWIFTTX_BLOCK_FILTERING_DEFAULT 1424217600        //2015-2-18
@@ -60,6 +61,7 @@ using namespace boost;
                                                                   // Set this to zero to emulate classic behaviour
 #define SPORK_17_PROPOSAL_VETO_DEFAULT 2000000001
 #define SPORK_18_KILL_STRAGGLERS_DEFAULT 0
+#define SPORK_19_FAKE_STAKE_FIX_DEFAULT 4070908800
 
 class CSporkMessage;
 class CSporkManager;