WalletApi: getMultisigInfo entry for gui wallets

WalletApi: makeMultisig call introduced

WalletApi: finalizeMultisig call introduced

WalletApi: new calls exportMultisigImages and importMultisigImages

WalletApi: method to return multisig wallet creation state

WalletApi: create multisig transaction, sign multisig transaction, commit transaction and get multisig data are added

WalletApi: identation and style fixes

5 files changed, 301 insertions, 0 deletions

diff --git a/src/wallet/api/pending_transaction.cpp b/src/wallet/api/pending_transaction.cpp
index ff4619f0f..8d200220d 100644
--- a/src/wallet/api/pending_transaction.cpp
+++ b/src/wallet/api/pending_transaction.cpp
@@ -34,6 +34,7 @@
 
 #include "cryptonote_basic/cryptonote_format_utils.h"
 #include "cryptonote_basic/cryptonote_basic_impl.h"
+#include "common/base58.h"
 
 #include <memory>
 #include <vector>
@@ -102,6 +103,11 @@ bool PendingTransactionImpl::commit(const std::string &filename, bool overwrite)
       }
       // Commit tx
       else {
+        auto multisigState = m_wallet.multisig();
+        if (multisigState.isMultisig && m_signers.size() < multisigState.threshold) {
+            throw runtime_error("Not enough signers to send multisig transaction");
+        }
+
         m_wallet.pauseRefresh();
         while (!m_pending_tx.empty()) {
             auto & ptx = m_pending_tx.back();
@@ -188,6 +194,53 @@ std::vector<std::set<uint32_t>> PendingTransactionImpl::subaddrIndices() const
     return result;
 }
 
+std::string PendingTransactionImpl::multisigSignData() {
+    try {
+        if (!m_wallet.multisig().isMultisig) {
+            throw std::runtime_error("wallet is not multisig");
+        }
+
+        auto cipher = m_wallet.m_wallet->save_multisig_tx(m_pending_tx);
+        return epee::string_tools::buff_to_hex_nodelimer(cipher);
+    } catch (const std::exception& e) {
+        m_status = Status_Error;
+        m_errorString = std::string(tr("Couldn't multisig sign data: ")) + e.what();
+    }
+
+    return std::string();
+}
+
+void PendingTransactionImpl::signMultisigTx() {
+    try {
+        std::vector<crypto::hash> ignore;
+
+        tools::wallet2::multisig_tx_set txSet;
+        txSet.m_ptx = m_pending_tx;
+        txSet.m_signers = m_signers;
+
+        if (!m_wallet.m_wallet->sign_multisig_tx(txSet, ignore)) {
+            throw std::runtime_error("couldn't sign multisig transaction");
+        }
+
+        std::swap(m_pending_tx, txSet.m_ptx);
+        std::swap(m_signers, txSet.m_signers);
+    } catch (const std::exception& e) {
+        m_status = Status_Error;
+        m_errorString = std::string(tr("Couldn't sign multisig transaction: ")) + e.what();
+    }
+}
+
+std::vector<std::string> PendingTransactionImpl::signersKeys() const {
+    std::vector<std::string> keys;
+    keys.reserve(m_signers.size());
+
+    for (const auto& signer: m_signers) {
+        keys.emplace_back(tools::base58::encode(cryptonote::t_serializable_object_to_blob(signer)));
+    }
+
+    return keys;
+}
+
 }
 
 namespace Bitmonero = Monero;
diff --git a/src/wallet/api/pending_transaction.h b/src/wallet/api/pending_transaction.h
index d0bd66eb5..4f963c134 100644
--- a/src/wallet/api/pending_transaction.h
+++ b/src/wallet/api/pending_transaction.h
@@ -55,6 +55,10 @@ public:
     std::vector<std::set<uint32_t>> subaddrIndices() const;
     // TODO: continue with interface;
 
+    std::string multisigSignData();
+    void signMultisigTx();
+    std::vector<std::string> signersKeys() const;
+
 private:
     friend class WalletImpl;
     WalletImpl &m_wallet;
@@ -62,6 +66,7 @@ private:
     int  m_status;
     std::string m_errorString;
     std::vector<tools::wallet2::pending_tx> m_pending_tx;
+    std::unordered_set<crypto::public_key> m_signers;
 };
 
 
diff --git a/src/wallet/api/wallet.cpp b/src/wallet/api/wallet.cpp
index 36c895aca..ade7b461c 100644
--- a/src/wallet/api/wallet.cpp
+++ b/src/wallet/api/wallet.cpp
@@ -77,6 +77,36 @@ namespace {
       dir /= ".shared-ringdb";
       return dir.string();
     }
+
+    void checkMultisigWalletReady(const tools::wallet2* wallet) {
+        if (!wallet) {
+            throw runtime_error("Wallet is not initialized yet");
+        }
+
+        bool ready;
+        if (!wallet->multisig(&ready)) {
+            throw runtime_error("Wallet is not multisig");
+        }
+
+        if (!ready) {
+            throw runtime_error("Multisig wallet is not finalized yet");
+        }
+    }
+
+    void checkMultisigWalletNotReady(const tools::wallet2* wallet) {
+        if (!wallet) {
+            throw runtime_error("Wallet is not initialized yet");
+        }
+
+        bool ready;
+        if (!wallet->multisig(&ready)) {
+            throw runtime_error("Wallet is not multisig");
+        }
+
+        if (ready) {
+            throw runtime_error("Multisig wallet is already finalized");
+        }
+    }
 }
 
 struct Wallet2CallbackImpl : public tools::i_wallet2_callback
@@ -1058,6 +1088,132 @@ void WalletImpl::setSubaddressLabel(uint32_t accountIndex, uint32_t addressIndex
     }
 }
 
+MultisigState WalletImpl::multisig() const {
+    MultisigState state;
+    state.isMultisig = m_wallet->multisig(&state.isReady, &state.threshold, &state.total);
+
+    return state;
+}
+
+string WalletImpl::getMultisigInfo() const {
+    try {
+        clearStatus();
+        return m_wallet->get_multisig_info();
+    } catch (const exception& e) {
+        LOG_ERROR("Error on generating multisig info: ") << e.what();
+        setStatusError(string(tr("Failed to get multisig info: ")) + e.what());
+    }
+
+    return string();
+}
+
+string WalletImpl::makeMultisig(const vector<string>& info, uint32_t threshold) {
+    try {
+        clearStatus();
+
+        if (m_wallet->multisig()) {
+            throw runtime_error("Wallet is already multisig");
+        }
+
+        return m_wallet->make_multisig(epee::wipeable_string(m_password), info, threshold);
+    } catch (const exception& e) {
+        LOG_ERROR("Error on making multisig wallet: ") << e.what();
+        setStatusError(string(tr("Failed to make multisig: ")) + e.what());
+    }
+
+    return string();
+}
+
+bool WalletImpl::finalizeMultisig(const vector<string>& extraMultisigInfo) {
+    try {
+        clearStatus();
+        checkMultisigWalletNotReady(m_wallet);
+
+        if (m_wallet->finalize_multisig(epee::wipeable_string(m_password), extraMultisigInfo)) {
+            return true;
+        }
+
+        setStatusError(tr("Failed to finalize multisig wallet creation"));
+    } catch (const exception& e) {
+        LOG_ERROR("Error on finalizing multisig wallet creation: ") << e.what();
+        setStatusError(string(tr("Failed to finalize multisig wallet creation: ")) + e.what());
+    }
+
+    return false;
+}
+
+bool WalletImpl::exportMultisigImages(string& images) {
+    try {
+        clearStatus();
+        checkMultisigWalletReady(m_wallet);
+
+        auto blob = m_wallet->export_multisig();
+        images = epee::string_tools::buff_to_hex_nodelimer(blob);
+        return true;
+    } catch (const exception& e) {
+        LOG_ERROR("Error on exporting multisig images: ") << e.what();
+        setStatusError(string(tr("Failed to export multisig images: ")) + e.what());
+    }
+
+    return false;
+}
+
+size_t WalletImpl::importMultisigImages(const vector<string>& images) {
+    try {
+        clearStatus();
+        checkMultisigWalletReady(m_wallet);
+
+        std::vector<std::string> blobs;
+        blobs.reserve(images.size());
+
+        for (const auto& image: images) {
+            std::string blob;
+            if (!epee::string_tools::parse_hexstr_to_binbuff(image, blob)) {
+                LOG_ERROR("Failed to parse imported multisig images");
+                setStatusError(tr("Failed to parse imported multisig images"));
+                return 0;
+            }
+
+            blobs.emplace_back(std::move(blob));
+        }
+
+        return m_wallet->import_multisig(blobs);
+    } catch (const exception& e) {
+        LOG_ERROR("Error on importing multisig images: ") << e.what();
+        setStatusError(string(tr("Failed to import multisig images: ")) + e.what());
+    }
+
+    return 0;
+}
+
+PendingTransaction* WalletImpl::restoreMultisigTransaction(const string& signData) {
+    try {
+        clearStatus();
+        checkMultisigWalletReady(m_wallet);
+
+        string binary;
+        if (!epee::string_tools::parse_hexstr_to_binbuff(signData, binary)) {
+            throw runtime_error("Failed to deserialize multisig transaction");
+        }
+
+        tools::wallet2::multisig_tx_set txSet;
+        if (!m_wallet->load_multisig_tx(binary, txSet, {})) {
+          throw runtime_error("couldn't parse multisig transaction data");
+        }
+
+        auto ptx = new PendingTransactionImpl(*this);
+        ptx->m_pending_tx = txSet.m_ptx;
+        ptx->m_signers = txSet.m_signers;
+
+        return ptx;
+    } catch (exception& e) {
+        LOG_ERROR("Error on restoring multisig transaction: ") << e.what();
+        setStatusError(string(tr("Failed to restore multisig transaction: ")) + e.what());
+    }
+
+    return nullptr;
+}
+
 // TODO:
 // 1 - properly handle payment id (add another menthod with explicit 'payment_id' param)
 // 2 - check / design how "Transaction" can be single interface
@@ -1095,6 +1251,7 @@ PendingTransaction *WalletImpl::createTransaction(const string &dst_addr, const
             break;
         }
 
+
         std::vector<uint8_t> extra;
         // if dst_addr is not an integrated address, parse payment_id
         if (!info.has_payment_id && !payment_id.empty()) {
@@ -1155,6 +1312,9 @@ PendingTransaction *WalletImpl::createTransaction(const string &dst_addr, const
                                                                           extra, subaddr_account, subaddr_indices, m_trustedDaemon);
             }
 
+            if (multisig().isMultisig) {
+                transaction->m_signers = m_wallet->make_multisig_tx_set(transaction->m_pending_tx).m_signers;
+            }
         } catch (const tools::error::daemon_busy&) {
             // TODO: make it translatable with "tr"?
             setStatusError(tr("daemon is busy. Please try again later."));
diff --git a/src/wallet/api/wallet.h b/src/wallet/api/wallet.h
index 7a0526e0a..e0e627c36 100644
--- a/src/wallet/api/wallet.h
+++ b/src/wallet/api/wallet.h
@@ -127,6 +127,14 @@ public:
     std::string getSubaddressLabel(uint32_t accountIndex, uint32_t addressIndex) const;
     void setSubaddressLabel(uint32_t accountIndex, uint32_t addressIndex, const std::string &label);
 
+    MultisigState multisig() const override;
+    std::string getMultisigInfo() const override;
+    std::string makeMultisig(const std::vector<std::string>& info, uint32_t threshold) override;
+    bool finalizeMultisig(const std::vector<std::string>& extraMultisigInfo) override;
+    bool exportMultisigImages(std::string& images) override;
+    size_t importMultisigImages(const std::vector<std::string>& images) override;
+    PendingTransaction*  restoreMultisigTransaction(const std::string& signData) override;
+
     PendingTransaction * createTransaction(const std::string &dst_addr, const std::string &payment_id,
                                         optional<uint64_t> amount, uint32_t mixin_count,
                                         PendingTransaction::Priority priority = PendingTransaction::Priority_Low,
diff --git a/src/wallet/api/wallet2_api.h b/src/wallet/api/wallet2_api.h
index 6ffef4400..f762f37c5 100644
--- a/src/wallet/api/wallet2_api.h
+++ b/src/wallet/api/wallet2_api.h
@@ -100,6 +100,30 @@ struct PendingTransaction
     virtual uint64_t txCount() const = 0;
     virtual std::vector<uint32_t> subaddrAccount() const = 0;
     virtual std::vector<std::set<uint32_t>> subaddrIndices() const = 0;
+
+    /**
+     * @brief multisigSignData
+     * @return encoded multisig transaction with signers' keys.
+     *         Transfer this data to another wallet participant to sign it.
+     *         Assumed use case is:
+     *         1. Initiator:
+     *              auto data = pendingTransaction->multisigSignData();
+     *         2. Signer1:
+     *              pendingTransaction = wallet->restoreMultisigTransaction(data);
+     *              pendingTransaction->signMultisigTx();
+     *              auto signed = pendingTransaction->multisigSignData();
+     *         3. Signer2:
+     *              pendingTransaction = wallet->restoreMultisigTransaction(signed);
+     *              pendingTransaction->signMultisigTx();
+     *              pendingTransaction->commit();
+     */
+    virtual std::string multisigSignData() = 0;
+    virtual void signMultisigTx() = 0;
+    /**
+     * @brief signersKeys
+     * @return vector of base58-encoded signers' public keys
+     */
+    virtual std::vector<std::string> signersKeys() const = 0;
 };
 
 /**
@@ -291,6 +315,15 @@ struct SubaddressAccount
     virtual void refresh() = 0;
 };
 
+struct MultisigState {
+    MultisigState() : isMultisig(false), isReady(false), threshold(0), total(0) {}
+
+    bool isMultisig;
+    bool isReady;
+    uint32_t threshold;
+    uint32_t total;
+};
+
 struct WalletListener
 {
     virtual ~WalletListener() = 0;
@@ -630,6 +663,48 @@ struct Wallet
      */
     virtual void setSubaddressLabel(uint32_t accountIndex, uint32_t addressIndex, const std::string &label) = 0;
 
+    /**
+     * @brief multisig - returns current state of multisig wallet creation process
+     * @return MultisigState struct
+     */
+    virtual MultisigState multisig() const = 0;
+    /**
+     * @brief getMultisigInfo
+     * @return serialized and signed multisig info string
+     */
+    virtual std::string getMultisigInfo() const = 0;
+    /**
+     * @brief makeMultisig - switches wallet in multisig state. The one and only creation phase for N / N wallets
+     * @param info - vector of multisig infos from other participants obtained with getMulitisInfo call
+     * @param threshold - number of required signers to make valid transaction. Must be equal to number of participants (N) or N - 1
+     * @return in case of N / N wallets returns empty string since no more key exchanges needed. For N - 1 / N wallets returns base58 encoded extra multisig info
+     */
+    virtual std::string makeMultisig(const std::vector<std::string>& info, uint32_t threshold) = 0;
+    /**
+     * @brief finalizeMultisig - finalizes N - 1 / N multisig wallets creation
+     * @param extraMultisigInfo - wallet participants' extra multisig info obtained with makeMultisig call
+     * @return true if success
+     */
+    virtual bool finalizeMultisig(const std::vector<std::string>& extraMultisigInfo) = 0;
+    /**
+     * @brief exportMultisigImages - exports transfers' key images
+     * @param images - output paramter for hex encoded array of images
+     * @return true if success
+     */
+    virtual bool exportMultisigImages(std::string& images) = 0;
+    /**
+     * @brief importMultisigImages - imports other participants' multisig images
+     * @param images - array of hex encoded arrays of images obtained with exportMultisigImages
+     * @return number of imported images
+     */
+    virtual size_t importMultisigImages(const std::vector<std::string>& images) = 0;
+
+    /**
+     * @brief restoreMultisigTransaction creates PendingTransaction from signData
+     * @param signData encrypted unsigned transaction. Obtained with PendingTransaction::multisigSignData
+     * @return PendingTransaction
+     */
+    virtual PendingTransaction*  restoreMultisigTransaction(const std::string& signData) = 0;
     /*!
      * \brief createTransaction creates transaction. if dst_addr is an integrated address, payment_id is ignored
      * \param dst_addr          destination address as string