add consensus.mandatory_coinbase_destination

Author: instagibbs

src/chainparams.cpp

@@ -322,6 +322,9 @@ class CRegTestParams : public CChainParams {
         assert(consensus.hashGenesisBlock == uint256S("0x0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206"));
         assert(genesis.hashMerkleRoot == uint256S("0x4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"));
 
+        // All non-zero coinbase outputs must go to this scriptPubKey
+        consensus.mandatory_coinbase_destination = CScript(ParseHex(gArgs.GetArg("-con_mandatorycoinbase", ""))); // Blank script allows any coinbase destination
+
         vFixedSeeds.clear(); //!< Regtest mode doesn't have any fixed seeds.
         vSeeds.clear();      //!< Regtest mode doesn't have any DNS seeds.
 

src/chainparamsbase.cpp

@@ -20,6 +20,7 @@ void SetupChainParamsBaseOptions()
     gArgs.AddArg("-regtest", "Enter regression test mode, which uses a special chain in which blocks can be solved instantly. "
                                    "This is intended for regression testing tools and app development.", true, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-testnet", "Use the test chain", false, OptionsCategory::CHAINPARAMS);
+    gArgs.AddArg("-con_mandatorycoinbase", "All non-zero valued coinbase outputs must go to this scriptPubKey, if set.", false, OptionsCategory::CHAINPARAMS);
 }
 
 static std::unique_ptr<CBaseChainParams> globalChainBaseParams;

src/consensus/params.h

@@ -11,6 +11,8 @@
 #include <map>
 #include <string>
 
+#include <script/script.h> // mandatory_coinbase_destination
+
 namespace Consensus {
 
 enum DeploymentPos
@@ -75,6 +77,9 @@ struct Params {
     int64_t DifficultyAdjustmentInterval() const { return nPowTargetTimespan / nPowTargetSpacing; }
     uint256 nMinimumChainWork;
     uint256 defaultAssumeValid;
+
+    // Elements-specific chainparams
+    CScript mandatory_coinbase_destination;
 };
 } // namespace Consensus
 

src/validation.cpp

@@ -1847,6 +1847,17 @@ bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBl
 
     nBlocksTotal++;
 
+    // Check that all non-zero coinbase outputs pay to the required destination
+    const CScript& mandatory_coinbase_destination = chainparams.GetConsensus().mandatory_coinbase_destination;
+    if (mandatory_coinbase_destination != CScript()) {
+        for (auto& txout : block.vtx[0]->vout) {
+            if (txout.scriptPubKey != mandatory_coinbase_destination && txout.nValue != 0) {
+                return state.DoS(100, error("ConnectBlock(): Coinbase outputs didnt match required scriptPubKey"),
+                                 REJECT_INVALID, "bad-coinbase-txos");
+            }
+        }
+    }
+
     bool fScriptChecks = true;
     if (!hashAssumeValid.IsNull()) {
         // We've been configured with the hash of a block which has been externally verified to have a valid history.