[0.17] MODIFIED: blockheaders include block height, nodes validate it

src/chain.h

@@ -210,6 +210,7 @@ class CBlockIndex
     int32_t nVersion;
     uint256 hashMerkleRoot;
     uint32_t nTime;
+    uint32_t block_height;
     uint32_t nBits;
     uint32_t nNonce;
 
@@ -238,6 +239,7 @@ class CBlockIndex
         nVersion       = 0;
         hashMerkleRoot = uint256();
         nTime          = 0;
+        block_height   = 0;
         nBits          = 0;
         nNonce         = 0;
     }
@@ -254,6 +256,7 @@ class CBlockIndex
         nVersion       = block.nVersion;
         hashMerkleRoot = block.hashMerkleRoot;
         nTime          = block.nTime;
+        block_height   = block.block_height;
         nBits          = block.nBits;
         nNonce         = block.nNonce;
     }
@@ -284,6 +287,7 @@ class CBlockIndex
             block.hashPrevBlock = pprev->GetBlockHash();
         block.hashMerkleRoot = hashMerkleRoot;
         block.nTime          = nTime;
+        block.block_height   = block_height;
         block.nBits          = nBits;
         block.nNonce         = nNonce;
         return block;
@@ -403,6 +407,9 @@ class CDiskBlockIndex : public CBlockIndex
         READWRITE(hashPrev);
         READWRITE(hashMerkleRoot);
         READWRITE(nTime);
+        if (g_con_blockheightinheader) {
+            READWRITE(block_height);
+        }
         READWRITE(nBits);
         READWRITE(nNonce);
     }
@@ -414,6 +421,7 @@ class CDiskBlockIndex : public CBlockIndex
         block.hashPrevBlock   = hashPrev;
         block.hashMerkleRoot  = hashMerkleRoot;
         block.nTime           = nTime;
+        block.block_height    = block_height;
         block.nBits           = nBits;
         block.nNonce          = nNonce;
         return block.GetHash();

src/chainparams.cpp

@@ -4,9 +4,10 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <chainparams.h>
-#include <consensus/merkle.h>
 
 #include <chainparamsseeds.h>
+#include <consensus/merkle.h>
+#include <hash.h>
 #include <tinyformat.h>
 #include <util.h>
 #include <utilstrencodings.h>
@@ -17,13 +18,13 @@
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/split.hpp>
 
-static CBlock CreateGenesisBlock(const char* pszTimestamp, const CScript& genesisOutputScript, uint32_t nTime, uint32_t nNonce, uint32_t nBits, int32_t nVersion, const CAmount& genesisReward)
+static CBlock CreateGenesisBlock(const CScript& coinbase_sig, const CScript& genesisOutputScript, uint32_t nTime, uint32_t nNonce, uint32_t nBits, int32_t nVersion, const CAmount& genesisReward)
 {
     CMutableTransaction txNew;
     txNew.nVersion = 1;
     txNew.vin.resize(1);
     txNew.vout.resize(1);
-    txNew.vin[0].scriptSig = CScript() << 486604799 << CScriptNum(4) << std::vector<unsigned char>((const unsigned char*)pszTimestamp, (const unsigned char*)pszTimestamp + strlen(pszTimestamp));
+    txNew.vin[0].scriptSig = coinbase_sig;
     txNew.vout[0].nValue = genesisReward;
     txNew.vout[0].scriptPubKey = genesisOutputScript;
 
@@ -38,6 +39,12 @@ static CBlock CreateGenesisBlock(const char* pszTimestamp, const CScript& genesi
     return genesis;
 }
 
+static CBlock CreateGenesisBlock(const char* pszTimestamp, const CScript& genesisOutputScript, uint32_t nTime, uint32_t nNonce, uint32_t nBits, int32_t nVersion, const CAmount& genesisReward)
+{
+    CScript coinbase_sig = CScript() << 486604799 << CScriptNum(4) << std::vector<unsigned char>((const unsigned char*)pszTimestamp, (const unsigned char*)pszTimestamp + strlen(pszTimestamp));
+    return CreateGenesisBlock(coinbase_sig, genesisOutputScript, nTime, nNonce, nBits, nVersion, genesisReward);
+}
+
 /**
  * Build the genesis block. Note that the output of its generation
  * transaction cannot be spent since it did not originally exist in the
@@ -403,6 +410,7 @@ class CCustomParams : public CRegTestParams {
     {
         UpdateVersionBitsParametersFromArgs(args);
 
+        consensus.genesis_style = args.GetArg("-con_genesis_style", "default_style");
         consensus.nSubsidyHalvingInterval = args.GetArg("-con_nsubsidyhalvinginterval", consensus.nSubsidyHalvingInterval);
         consensus.BIP16Exception = uint256S(args.GetArg("-con_bip16exception", "0x0"));
         consensus.BIP34Height = args.GetArg("-con_bip34height", consensus.BIP34Height);
@@ -420,6 +428,10 @@ class CCustomParams : public CRegTestParams {
         consensus.nMinimumChainWork = uint256S(args.GetArg("-con_nminimumchainwork", "0x0"));
         consensus.defaultAssumeValid = uint256S(args.GetArg("-con_defaultassumevalid", "0x00"));
 
+        // Note: g_con_blockheightinheader is used instead of consensus.blockheight_in_header to avoid
+        // circular dependency
+        consensus.blockheight_in_header = g_con_blockheightinheader = gArgs.GetBoolArg("-con_blockheightinheader", false);
+
         // All non-zero coinbase outputs must go to this scriptPubKey
         std::vector<unsigned char> man_bytes = ParseHex(gArgs.GetArg("-con_mandatorycoinbase", ""));
         consensus.mandatory_coinbase_destination = CScript(man_bytes.begin(), man_bytes.end()); // Blank script allows any coinbase destination
@@ -457,12 +469,30 @@ class CCustomParams : public CRegTestParams {
         }
     }
 
+    void SetGenesisBlock()
+    {
+        if (consensus.genesis_style == "regtest2_style") {
+            // Same style as in https://github.com/bitcoin/bitcoin/pull/8994
+            genesis = CreateGenesisBlock(strNetworkID.c_str(), CScript(OP_TRUE), 1296688602, 2, 0x207fffff, 1, 50 * COIN);
+
+        } else if (consensus.genesis_style == "default_style") {
+            CHashWriter h(SER_DISK, 0);
+            h << strNetworkID;
+            uint256 hash = h.GetHash();
+            CScript coinbase_sig = CScript() << std::vector<uint8_t>(hash.begin(), hash.end());
+            genesis = CreateGenesisBlock(coinbase_sig, CScript(OP_TRUE), 1296688602, 2, 0x207fffff, 1, 50 * COIN);
+
+        } else {
+            throw std::runtime_error(strprintf("%s: Unknown consensus.genesis_style %s.", __func__, consensus.genesis_style));
+        }
+    }
+
 public:
     CCustomParams(const std::string& chain, ArgsManager& args) : CRegTestParams(args)
     {
         strNetworkID = chain;
         UpdateFromArgs(args);
-        genesis = CreateGenesisBlock(strNetworkID.c_str(), CScript(OP_TRUE), 1296688602, 2, 0x207fffff, 1, 50 * COIN);
+        SetGenesisBlock();
         consensus.hashGenesisBlock = genesis.GetHash();
     }
 };

src/chainparamsbase.cpp

@@ -21,9 +21,11 @@ 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_genesis_style=<style>", "Use genesis style <style> (default: default_style). Allowed values: default_style, regtest2_style", true, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-vbparams=deployment:start:end", "Use given start/end times for specified version bits deployment (regtest or custom only)", true, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-con_mandatorycoinbase", "All non-zero valued coinbase outputs must go to this scriptPubKey, if set.", false, OptionsCategory::CHAINPARAMS);
     gArgs.AddArg("-seednode=<ip>", "Use specified node as seed node. This option can be specified multiple times to connect to multiple nodes. (custom only)", true, OptionsCategory::CHAINPARAMS);
+    gArgs.AddArg("-con_blockheightinheader", "Whether the chain includes the block height directly in the header, for easier validation of block height in low-resource environments.", false, OptionsCategory::CHAINPARAMS);
 }
 
 static std::unique_ptr<CBaseChainParams> globalChainBaseParams;

src/consensus/params.h

@@ -49,6 +49,7 @@ struct BIP9Deployment {
  * Parameters that influence chain consensus.
  */
 struct Params {
+    std::string genesis_style;
     uint256 hashGenesisBlock;
     int nSubsidyHalvingInterval;
     /* Block hash that is excepted from BIP16 enforcement */
@@ -80,6 +81,7 @@ struct Params {
 
     // Elements-specific chainparams
     CScript mandatory_coinbase_destination;
+    bool blockheight_in_header;
 };
 } // namespace Consensus
 

src/miner.cpp

@@ -168,6 +168,9 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& sc
     // Fill in header
     pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
     UpdateTime(pblock, chainparams.GetConsensus(), pindexPrev);
+    if (g_con_blockheightinheader) {
+        pblock->block_height = nHeight;
+    }
     pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock, chainparams.GetConsensus());
     pblock->nNonce         = 0;
     pblocktemplate->vTxSigOpsCost[0] = WITNESS_SCALE_FACTOR * GetLegacySigOpCount(*pblock->vtx[0]);

src/primitives/block.cpp

@@ -10,6 +10,8 @@
 #include <utilstrencodings.h>
 #include <crypto/common.h>
 
+bool g_con_blockheightinheader = false;
+
 uint256 CBlockHeader::GetHash() const
 {
     return SerializeHash(*this);

src/primitives/block.h

@@ -10,6 +10,11 @@
 #include <serialize.h>
 #include <uint256.h>
 
+/** 
+ * Also found in consensus params as blockheight_in_header (circular dep otherwise)
+ */
+extern bool g_con_blockheightinheader;
+
 /** Nodes collect new transactions into a block, hash them into a hash tree,
  * and scan through nonce values to make the block's hash satisfy proof-of-work
  * requirements.  When they solve the proof-of-work, they broadcast the block
@@ -25,6 +30,9 @@ class CBlockHeader
     uint256 hashPrevBlock;
     uint256 hashMerkleRoot;
     uint32_t nTime;
+    // Height in header as well as in coinbase for easier hsm validation
+    // Is set for serialization with `-con_blockheightinheader=1`
+    uint32_t block_height;
     uint32_t nBits;
     uint32_t nNonce;
 
@@ -41,6 +49,9 @@ class CBlockHeader
         READWRITE(hashPrevBlock);
         READWRITE(hashMerkleRoot);
         READWRITE(nTime);
+        if (g_con_blockheightinheader) {
+            READWRITE(block_height);
+        }
         READWRITE(nBits);
         READWRITE(nNonce);
     }
@@ -51,6 +62,7 @@ class CBlockHeader
         hashPrevBlock.SetNull();
         hashMerkleRoot.SetNull();
         nTime = 0;
+        block_height = 0;
         nBits = 0;
         nNonce = 0;
     }
@@ -111,6 +123,7 @@ class CBlock : public CBlockHeader
         block.hashPrevBlock  = hashPrevBlock;
         block.hashMerkleRoot = hashMerkleRoot;
         block.nTime          = nTime;
+        block.block_height   = block_height;
         block.nBits          = nBits;
         block.nNonce         = nNonce;
         return block;

src/validation.cpp

@@ -3263,6 +3263,11 @@ static bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationSta
     if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast())
         return state.Invalid(false, REJECT_INVALID, "time-too-old", "block's timestamp is too early");
 
+    // Check height in header against prev
+    if (g_con_blockheightinheader && (uint32_t)nHeight != block.block_height)
+        return state.Invalid(error("%s: block height in header is incorrect", __func__),
+                             REJECT_INVALID, "bad-header-height");
+
     // Check timestamp
     if (block.GetBlockTime() > nAdjustedTime + MAX_FUTURE_BLOCK_TIME)
         return state.Invalid(false, REJECT_INVALID, "time-too-new", "block timestamp too far in the future");