Merge #741: Allow specifying peg-in data in createrawtransaction

5a4d611 Test raw transaction peg-in (Andrew Chow) ac6f052 Have find_vout_for_address only get non-confidential address when using elements chain (Andrew Chow) cefe407 Allow specifying peg-in info in raw transaction RPC inputs (Andrew Chow) 42babb8 Refactor peg-in input construction into its own function in rpc/rawtransaction.cpp (Andrew Chow) a90d152 Refactor peg-in witness construction to it's own function (Andrew Chow) Pull request description: Adds to `createrawtransaction` the fields `pegin_bitcoin_tx`, `pegin_txout_proof`, and `pegin_claim_script` so that raw transactions can contain peg-in inputs too. Since `ConstructTransaction` is used by `createpsbt` and `walletcreatefundedpsbt` but those should not support peg-ins yet (the peg-in data should go into PSBT fields for peg-ins but those don't exist yet), an argument is added to it to optionally reject peg-in data. Tree-SHA512: fcf3e4be87f92bfc5b00321bec405001d98615cefb76118345e0c759c6bfcb90b6050735960b6fbdbe26479fa11c9273f9963873a8adc1fbad9ed31dc7953ee0
ElementsProject · Oct 16, 2019 · 0d2832a · 0d2832a
2 parents 63701d1 + 5a4d611
commit 0d2832a
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Showing 8 changed files with 260 additions and 121 deletions.
diff --git a/src/pegins.cpp b/src/pegins.cpp
@@ -496,3 +496,45 @@ std::vector<std::pair<CScript, CScript>> GetValidFedpegScripts(const CBlockIndex
     fedpegscripts.resize(std::min(fedpegscripts.size(), params.total_valid_epochs));
     return fedpegscripts;
 }
+
+template<typename T_tx_ref, typename T_merkle_block>
+CScriptWitness CreatePeginWitnessInner(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const T_tx_ref& tx_ref, const T_merkle_block& merkle_block)
+{
+    std::vector<unsigned char> value_bytes;
+    CVectorWriter ss_val(0, 0, value_bytes, 0);
+    try {
+        ss_val << value;
+    } catch (...) {
+        throw std::ios_base::failure("Amount serialization is invalid.");
+    }
+
+    // Strip witness data for proof inclusion since only TXID-covered fields matters
+    CDataStream ss_tx(SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
+    ss_tx << tx_ref;
+    std::vector<unsigned char> tx_data_stripped(ss_tx.begin(), ss_tx.end());
+
+    // Serialize merkle block
+    CDataStream ss_txout_proof(SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
+    ss_txout_proof << merkle_block;
+    std::vector<unsigned char> txout_proof_bytes(ss_txout_proof.begin(), ss_txout_proof.end());
+
+    // Construct pegin proof
+    CScriptWitness pegin_witness;
+    std::vector<std::vector<unsigned char> >& stack = pegin_witness.stack;
+    stack.push_back(value_bytes);
+    stack.push_back(std::vector<unsigned char>(asset.begin(), asset.end()));
+    stack.push_back(std::vector<unsigned char>(genesis_hash.begin(), genesis_hash.end()));
+    stack.push_back(std::vector<unsigned char>(claim_script.begin(), claim_script.end()));
+    stack.push_back(tx_data_stripped);
+    stack.push_back(txout_proof_bytes);
+    return pegin_witness;
+}
+
+CScriptWitness CreatePeginWitness(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const CTransactionRef& tx_ref, const CMerkleBlock& merkle_block)
+{
+    return CreatePeginWitnessInner(value, asset, genesis_hash, claim_script, tx_ref, merkle_block);
+}
+CScriptWitness CreatePeginWitness(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const Sidechain::Bitcoin::CTransactionRef& tx_ref, const Sidechain::Bitcoin::CMerkleBlock& merkle_block)
+{
+    return CreatePeginWitnessInner(value, asset, genesis_hash, claim_script, tx_ref, merkle_block);
+}
diff --git a/src/pegins.h b/src/pegins.h
@@ -7,7 +7,9 @@
 
 #include <amount.h>
 #include <consensus/params.h>
+#include <merkleblock.h>
 #include <primitives/bitcoin/transaction.h>
+#include <primitives/bitcoin/merkleblock.h>
 #include <primitives/transaction.h>
 #include <script/script.h>
 #include <chain.h>
@@ -38,4 +40,9 @@ bool MatchLiquidWatchman(const CScript& script);
  * scriptPubKey for the script, the second is the witnessScript. */
 std::vector<std::pair<CScript, CScript>> GetValidFedpegScripts(const CBlockIndex* pblockindex, const Consensus::Params& params, bool nextblock_validation);
 
+/** Create the peg-in witness stack */
+CScriptWitness CreatePeginWitness(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const CTransactionRef& tx_ref, const CMerkleBlock& merkle_block);
+CScriptWitness CreatePeginWitness(const CAmount& value, const CAsset& asset, const uint256& genesis_hash, const CScript& claim_script, const Sidechain::Bitcoin::CTransactionRef& tx_ref, const Sidechain::Bitcoin::CMerkleBlock& merkle_block);
+
+
 #endif // BITCOIN_PEGINS_H
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
@@ -4,6 +4,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <asset.h>
+#include <block_proof.h>
 #include <chain.h>
 #include <coins.h>
 #include <compat/byteswap.h>
@@ -21,6 +22,8 @@
 #include <policy/policy.h>
 #include <policy/rbf.h>
 #include <primitives/transaction.h>
+#include <primitives/bitcoin/merkleblock.h>
+#include <primitives/bitcoin/transaction.h>
 #include <psbt.h>
 #include <rpc/rawtransaction.h>
 #include <rpc/server.h>
@@ -363,7 +366,125 @@ static UniValue verifytxoutproof(const JSONRPCRequest& request)
     return res;
 }
 
-CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, const UniValue& rbf, const UniValue& assets_in, std::vector<CPubKey>* output_pubkeys_out)
+template<typename T_tx>
+unsigned int GetPeginTxnOutputIndex(const T_tx& txn, const CScript& witnessProgram, const std::vector<std::pair<CScript, CScript>>& fedpegscripts)
+{
+    for (const auto & scripts : fedpegscripts) {
+        CScript mainchain_script = GetScriptForWitness(calculate_contract(scripts.second, witnessProgram));
+        if (scripts.first.IsPayToScriptHash()) {
+            mainchain_script = GetScriptForDestination(ScriptHash(mainchain_script));
+        }
+        for (unsigned int nOut = 0; nOut < txn.vout.size(); nOut++)
+            if (txn.vout[nOut].scriptPubKey == mainchain_script) {
+                return nOut;
+            }
+        }
+    return txn.vout.size();
+}
+
+// Modifies an existing transaction input in-place to be a valid peg-in input, and inserts the witness if deemed valid.
+template<typename T_tx_ref, typename T_merkle_block>
+static void CreatePegInInputInner(CMutableTransaction& mtx, uint32_t input_idx, T_tx_ref& txBTCRef, T_merkle_block& merkleBlock, const std::set<CScript>& claim_scripts, const std::vector<unsigned char>& txData, const std::vector<unsigned char>& txOutProofData)
+{
+    if ((mtx.vin.size() > input_idx && !mtx.vin[input_idx].scriptSig.empty()) || (mtx.witness.vtxinwit.size() > input_idx && !mtx.witness.vtxinwit[input_idx].IsNull())) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Attempting to add a peg-in to an input that already has a scriptSig or witness");
+    }
+
+    CDataStream ssTx(txData, SER_NETWORK, PROTOCOL_VERSION);
+    try {
+        ssTx >> txBTCRef;
+    }
+    catch (...) {
+        throw JSONRPCError(RPC_TYPE_ERROR, "The included bitcoinTx is malformed. Are you sure that is the whole string?");
+    }
+
+    CDataStream ssTxOutProof(txOutProofData, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS);
+    try {
+        ssTxOutProof >> merkleBlock;
+    }
+    catch (...) {
+        throw JSONRPCError(RPC_TYPE_ERROR, "The included txoutproof is malformed. Are you sure that is the whole string?");
+    }
+
+    if (!ssTxOutProof.empty()) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid tx out proof");
+    }
+
+    std::vector<uint256> txHashes;
+    std::vector<unsigned int> txIndices;
+    if (merkleBlock.txn.ExtractMatches(txHashes, txIndices) != merkleBlock.header.hashMerkleRoot)
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid tx out proof");
+
+    if (txHashes.size() != 1 || txHashes[0] != txBTCRef->GetHash())
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "The txoutproof must contain bitcoinTx and only bitcoinTx");
+
+    CScript witness_script;
+    unsigned int nOut = txBTCRef->vout.size();
+    const auto fedpegscripts = GetValidFedpegScripts(chainActive.Tip(), Params().GetConsensus(), true /* nextblock_validation */);
+    for (const CScript& script : claim_scripts) {
+        nOut = GetPeginTxnOutputIndex(*txBTCRef, script, fedpegscripts);
+        if (nOut != txBTCRef->vout.size()) {
+            witness_script = script;
+            break;
+        }
+    }
+    if (nOut == txBTCRef->vout.size()) {
+        if (claim_scripts.size() == 1) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Given claim_script does not match the given Bitcoin transaction.");
+        } else {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, "Failed to find output in bitcoinTx to the mainchain_address from getpeginaddress");
+        }
+    }
+    assert(witness_script != CScript());
+
+    int version = -1;
+    std::vector<unsigned char> witness_program;
+    if (!witness_script.IsWitnessProgram(version, witness_program) || version != 0) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Given or recovered script is not a v0 witness program.");
+    }
+
+    CAmount value = 0;
+    if (!GetAmountFromParentChainPegin(value, *txBTCRef, nOut)) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Amounts to pegin must be explicit and asset must be %s", Params().GetConsensus().parent_pegged_asset.GetHex()));
+    }
+
+    // Add/replace input in mtx
+    if (mtx.vin.size() <= input_idx) {
+        mtx.vin.resize(input_idx + 1);
+    }
+    mtx.vin[input_idx] = CTxIn(COutPoint(txHashes[0], nOut), CScript(), ~(uint32_t)0);
+
+    // Construct pegin proof
+    CScriptWitness pegin_witness = CreatePeginWitness(value, Params().GetConsensus().pegged_asset, Params().ParentGenesisBlockHash(), witness_script, txBTCRef, merkleBlock);
+
+    // Peg-in witness isn't valid, even though the block header is(without depth check)
+    // We re-check depth before returning with more descriptive result
+    std::string err;
+    if (!IsValidPeginWitness(pegin_witness, fedpegscripts, mtx.vin[input_idx].prevout, err, false)) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Constructed peg-in witness is invalid: %s", err));
+    }
+
+    // Put input witness in transaction
+    mtx.vin[input_idx].m_is_pegin = true;
+    CTxInWitness txinwit;
+    txinwit.m_pegin_witness = pegin_witness;
+
+    if (mtx.witness.vtxinwit.size() <= input_idx) {
+        mtx.witness.vtxinwit.resize(input_idx + 1);
+    }
+    mtx.witness.vtxinwit[input_idx] = txinwit;
+}
+
+void CreatePegInInput(CMutableTransaction& mtx, uint32_t input_idx, CTransactionRef& tx_btc, CMerkleBlock& merkle_block, const std::set<CScript>& claim_scripts, const std::vector<unsigned char>& txData, const std::vector<unsigned char>& txOutProofData)
+{
+    CreatePegInInputInner(mtx, input_idx, tx_btc, merkle_block, claim_scripts, txData, txOutProofData);
+}
+void CreatePegInInput(CMutableTransaction& mtx, uint32_t input_idx, Sidechain::Bitcoin::CTransactionRef& tx_btc, Sidechain::Bitcoin::CMerkleBlock& merkle_block, const std::set<CScript>& claim_scripts, const std::vector<unsigned char>& txData, const std::vector<unsigned char>& txOutProofData)
+{
+    CreatePegInInputInner(mtx, input_idx, tx_btc, merkle_block, claim_scripts, txData, txOutProofData);
+}
+
+CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, const UniValue& rbf, const UniValue& assets_in, std::vector<CPubKey>* output_pubkeys_out, bool allow_peg_in)
 {
     if (inputs_in.isNull() || outputs_in.isNull())
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, arguments 1 and 2 must be non-null");
@@ -422,8 +543,43 @@ CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniVal
         }
 
         CTxIn in(COutPoint(txid, nOutput), CScript(), nSequence);
-
         rawTx.vin.push_back(in);
+
+        // Get the pegin stuff if it's there
+        const UniValue& pegin_tx = find_value(o, "pegin_bitcoin_tx");
+        const UniValue& pegin_tx_proof = find_value(o, "pegin_txout_proof");
+        const UniValue& pegin_script = find_value(o, "pegin_claim_script");
+        if (!pegin_tx.isNull() && !pegin_tx_proof.isNull() && !pegin_script.isNull() && allow_peg_in) {
+            if (!IsHex(pegin_script.get_str())) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Given claim_script is not hex.");
+            }
+            // If given manually, no need for it to be a witness script
+            std::vector<unsigned char> claim_script_bytes(ParseHex(pegin_script.get_str()));
+            CScript claim_script(claim_script_bytes.begin(), claim_script_bytes.end());
+            std::set<CScript> claim_scripts;
+            claim_scripts.insert(std::move(claim_script));
+            if (Params().GetConsensus().ParentChainHasPow()) {
+                Sidechain::Bitcoin::CTransactionRef tx_btc;
+                Sidechain::Bitcoin::CMerkleBlock merkle_block;
+                CreatePegInInput(rawTx, idx, tx_btc, merkle_block, claim_scripts, ParseHex(pegin_tx.get_str()), ParseHex(pegin_tx_proof.get_str()));
+                if (!CheckParentProofOfWork(merkle_block.header.GetHash(), merkle_block.header.nBits, Params().GetConsensus())) {
+                    throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid tx out proof");
+                }
+            } else {
+                CTransactionRef tx_btc;
+                CMerkleBlock merkle_block;
+                CreatePegInInput(rawTx, idx, tx_btc, merkle_block, claim_scripts, ParseHex(pegin_tx.get_str()), ParseHex(pegin_tx_proof.get_str()));
+                if (!CheckProofSignedParent(merkle_block.header, Params().GetConsensus())) {
+                    throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid tx out proof");
+                }
+            }
+        } else if (!pegin_tx.isNull() || !pegin_tx_proof.isNull() || !pegin_script.isNull()) {
+            if (allow_peg_in) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Some but not all pegin_ arguments provided");
+            } else {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "pegin_ arguments provided but this command does not support peg-ins");
+            }
+        }
     }
 
     if (!outputs_is_obj) {
@@ -558,6 +714,9 @@ static UniValue createrawtransaction(const JSONRPCRequest& request)
                                     {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The transaction id"},
                                     {"vout", RPCArg::Type::NUM, RPCArg::Optional::NO, "The output number"},
                                     {"sequence", RPCArg::Type::NUM, /* default */ "depends on the value of the 'replaceable' and 'locktime' arguments", "The sequence number"},
+                                    {"pegin_bitcoin_tx", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The raw bitcoin transaction (in hex) depositing bitcoin to the mainchain_address generated by getpeginaddress"},
+                                    {"pegin_txout_proof", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "A rawtxoutproof (in hex) generated by the mainchain daemon's `gettxoutproof` containing a proof of only bitcoin_tx"},
+                                    {"pegin_claim_script", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The claim script generated by getpeginaddress."},
                                 },
                                 },
                         },
@@ -1952,7 +2111,7 @@ UniValue createpsbt(const JSONRPCRequest& request)
     );
 
     std::vector<CPubKey> output_pubkeys;
-    CMutableTransaction rawTx = ConstructTransaction(request.params[0], request.params[1], request.params[2], request.params[3], request.params[4], &output_pubkeys);
+    CMutableTransaction rawTx = ConstructTransaction(request.params[0], request.params[1], request.params[2], request.params[3], request.params[4], &output_pubkeys, false /* allow_peg_in */);
 
     // Make a blank psbt
     PartiallySignedTransaction psbtx(rawTx);

diff --git a/src/rpc/rawtransaction.h b/src/rpc/rawtransaction.h
@@ -19,6 +19,10 @@ UniValue SignTransaction(interfaces::Chain& chain, CMutableTransaction& mtx, con
 /** Create a transaction from univalue parameters. If (and only if)
     output_pubkeys_out is null, the "nonce hack" of storing Confidential
     Assets output pubkeys in nonces will be used. */
-CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, const UniValue& rbf, const UniValue& assets_in, std::vector<CPubKey>* output_pubkeys_out = nullptr);
+CMutableTransaction ConstructTransaction(const UniValue& inputs_in, const UniValue& outputs_in, const UniValue& locktime, const UniValue& rbf, const UniValue& assets_in, std::vector<CPubKey>* output_pubkeys_out = nullptr, bool allow_peg_in = true);
+
+/** Create a peg-in input */
+void CreatePegInInput(CMutableTransaction& mtx, uint32_t input_idx, CTransactionRef& tx_btc, CMerkleBlock& merkle_block, const std::set<CScript>& claim_scripts, const std::vector<unsigned char>& txData, const std::vector<unsigned char>& txOutProofData);
+void CreatePegInInput(CMutableTransaction& mtx, uint32_t input_idx, Sidechain::Bitcoin::CTransactionRef& tx_btc, Sidechain::Bitcoin::CMerkleBlock& merkle_block, const std::set<CScript>& claim_scripts, const std::vector<unsigned char>& txData, const std::vector<unsigned char>& txOutProofData);
 
 #endif // BITCOIN_RPC_RAWTRANSACTION_H