Merge pull request #8551

eca7f6a Fix segfault restoring encrypted multisig seed (j-berman)
f713c3c Require user ack multisig is experimental to restore (j-berman)
564a7a3 multisig: fix #8537 seed restore (suggestions by @UkoeHB) (j-berman)

src/multisig/multisig_account.cpp

@@ -127,7 +127,7 @@ namespace multisig
   bool multisig_account::multisig_is_ready() const
   {
     if (main_kex_rounds_done())
-      return m_kex_rounds_complete >= multisig_kex_rounds_required(m_signers.size(), m_threshold) + 1;
+      return m_kex_rounds_complete >= multisig_setup_rounds_required(m_signers.size(), m_threshold);
     else
       return false;
   }
@@ -200,4 +200,11 @@ namespace multisig
     return num_signers - threshold + 1;
   }
   //----------------------------------------------------------------------------------------------------------------------
+  // EXTERNAL
+  //----------------------------------------------------------------------------------------------------------------------
+  std::uint32_t multisig_setup_rounds_required(const std::uint32_t num_signers, const std::uint32_t threshold)
+  {
+    return multisig_kex_rounds_required(num_signers, threshold) + 1;
+  }
+  //----------------------------------------------------------------------------------------------------------------------
 } //namespace multisig

src/multisig/multisig_account.h

@@ -245,4 +245,13 @@ namespace multisig
   * return: number of kex rounds required
   */
   std::uint32_t multisig_kex_rounds_required(const std::uint32_t num_signers, const std::uint32_t threshold);
+
+  /**
+  * brief: multisig_setup_rounds_required - The number of setup rounds required to produce an M-of-N shared key.
+  *    - A participant must complete all kex rounds and 1 initialization round.
+  * param: num_signers - number of participants in multisig (N)
+  * param: threshold - threshold of multisig (M)
+  * return: number of setup rounds required
+  */
+  std::uint32_t multisig_setup_rounds_required(const std::uint32_t num_signers, const std::uint32_t threshold);
 } //namespace multisig

src/multisig/multisig_account_kex_impl.cpp

@@ -74,7 +74,7 @@ namespace multisig
       "Multisig threshold may not be larger than number of signers.");
     CHECK_AND_ASSERT_THROW_MES(threshold > 0, "Multisig threshold must be > 0.");
     CHECK_AND_ASSERT_THROW_MES(round > 0, "Multisig kex round must be > 0.");
-    CHECK_AND_ASSERT_THROW_MES(round <= multisig_kex_rounds_required(num_signers, threshold) + 1,
+    CHECK_AND_ASSERT_THROW_MES(round <= multisig_setup_rounds_required(num_signers, threshold),
       "Trying to process multisig kex for an invalid round.");
   }
   //----------------------------------------------------------------------------------------------------------------------

src/simplewallet/simplewallet.cpp

@@ -4118,6 +4118,7 @@ bool simple_wallet::init(const boost::program_options::variables_map& vm)
 
   epee::wipeable_string multisig_keys;
   epee::wipeable_string password;
+  epee::wipeable_string seed_pass;
 
   if (!handle_command_line(vm))
     return false;
@@ -4134,6 +4135,17 @@ bool simple_wallet::init(const boost::program_options::variables_map& vm)
     if(!ask_wallet_create_if_needed()) return false;
   }
 
+  bool enable_multisig = false;
+  if (m_restore_multisig_wallet) {
+    fail_msg_writer() << tr("Multisig is disabled.");
+    fail_msg_writer() << tr("Multisig is an experimental feature and may have bugs. Things that could go wrong include: funds sent to a multisig wallet can't be spent at all, can only be spent with the participation of a malicious group member, or can be stolen by a malicious group member.");
+    if (!command_line::is_yes(input_line("Do you want to continue restoring a multisig wallet?", true))) {
+      message_writer() << tr("You have canceled restoring a multisig wallet.");
+      return false;
+    }
+    enable_multisig = true;
+  }
+
   if (!m_generate_new.empty() || m_restoring)
   {
     if (!m_subaddress_lookahead.empty() && !parse_subaddress_lookahead(m_subaddress_lookahead))
@@ -4213,20 +4225,10 @@ bool simple_wallet::init(const boost::program_options::variables_map& vm)
       auto pwd_container = password_prompter(tr("Enter seed offset passphrase, empty if none"), false);
       if (std::cin.eof() || !pwd_container)
         return false;
-      epee::wipeable_string seed_pass = pwd_container->password();
-      if (!seed_pass.empty())
-      {
-        if (m_restore_multisig_wallet)
-        {
-          crypto::secret_key key;
-          crypto::cn_slow_hash(seed_pass.data(), seed_pass.size(), (crypto::hash&)key);
-          sc_reduce32((unsigned char*)key.data);
-          multisig_keys = m_wallet->decrypt<epee::wipeable_string>(std::string(multisig_keys.data(), multisig_keys.size()), key, true);
-        }
-        else
+      seed_pass = pwd_container->password();
+      if (!seed_pass.empty() && !m_restore_multisig_wallet)
         m_recovery_key = cryptonote::decrypt_key(m_recovery_key, seed_pass);
     }
-    }
     if (!m_generate_from_view_key.empty())
     {
       m_wallet_file = m_generate_from_view_key;
@@ -4568,7 +4570,7 @@ bool simple_wallet::init(const boost::program_options::variables_map& vm)
       m_wallet_file = m_generate_new;
       boost::optional<epee::wipeable_string> r;
       if (m_restore_multisig_wallet)
-        r = new_wallet(vm, multisig_keys, old_language);
+        r = new_wallet(vm, multisig_keys, seed_pass, old_language);
       else
         r = new_wallet(vm, m_recovery_key, m_restore_deterministic_wallet, m_non_deterministic, old_language);
       CHECK_AND_ASSERT_MES(r, false, tr("account creation failed"));
@@ -4667,6 +4669,8 @@ bool simple_wallet::init(const boost::program_options::variables_map& vm)
       }
       m_wallet->set_refresh_from_block_height(m_restore_height);
     }
+    if (enable_multisig)
+      m_wallet->enable_multisig(true);
     m_wallet->rewrite(m_wallet_file, password);
   }
   else
@@ -5057,7 +5061,7 @@ boost::optional<epee::wipeable_string> simple_wallet::new_wallet(const boost::pr
 }
 //----------------------------------------------------------------------------------------------------
 boost::optional<epee::wipeable_string> simple_wallet::new_wallet(const boost::program_options::variables_map& vm,
-    const epee::wipeable_string &multisig_keys, const std::string &old_language)
+    const epee::wipeable_string &multisig_keys, const epee::wipeable_string &seed_pass, const std::string &old_language)
 {
   std::pair<std::unique_ptr<tools::wallet2>, tools::password_container> rc;
   try { rc = tools::wallet2::make_new(vm, false, password_prompter); }
@@ -5091,7 +5095,16 @@ boost::optional<epee::wipeable_string> simple_wallet::new_wallet(const boost::pr
 
   try
   {
+    if (seed_pass.empty())
       m_wallet->generate(m_wallet_file, std::move(rc.second).password(), multisig_keys, create_address_file);
+    else
+    {
+      crypto::secret_key key;
+      crypto::cn_slow_hash(seed_pass.data(), seed_pass.size(), (crypto::hash&)key);
+      sc_reduce32((unsigned char*)key.data);
+      const epee::wipeable_string &msig_keys = m_wallet->decrypt<epee::wipeable_string>(std::string(multisig_keys.data(), multisig_keys.size()), key, true);
+      m_wallet->generate(m_wallet_file, std::move(rc.second).password(), msig_keys, create_address_file);
+    }
     bool ready;
     uint32_t threshold, total;
     if (!m_wallet->multisig(&ready, &threshold, &total) || !ready)

src/simplewallet/simplewallet.h

@@ -101,7 +101,7 @@ namespace cryptonote
     boost::optional<epee::wipeable_string> new_wallet(const boost::program_options::variables_map& vm, const cryptonote::account_public_address& address,
         const boost::optional<crypto::secret_key>& spendkey, const crypto::secret_key& viewkey);
     boost::optional<epee::wipeable_string> new_wallet(const boost::program_options::variables_map& vm,
-        const epee::wipeable_string &multisig_keys, const std::string &old_language);
+        const epee::wipeable_string &multisig_keys, const epee::wipeable_string &seed_pass, const std::string &old_language);
     boost::optional<epee::wipeable_string> new_wallet(const boost::program_options::variables_map& vm);
     boost::optional<epee::wipeable_string> open_wallet(const boost::program_options::variables_map& vm);
     bool close_wallet();

src/wallet/wallet2.cpp

@@ -4691,7 +4691,8 @@ void wallet2::init_type(hw::device::device_type device_type)
 }
 
 /*!
- * \brief  Generates a wallet or restores one.
+ * \brief  Generates a wallet or restores one. Assumes the multisig setup
+ *         has already completed for the provided multisig info.
  * \param  wallet_              Name of wallet file
  * \param  password             Password of wallet file
  * \param  multisig_data        The multisig restore info and keys
@@ -4750,11 +4751,6 @@ void wallet2::generate(const std::string& wallet_, const epee::wipeable_string&
   crypto::public_key local_signer;
   THROW_WALLET_EXCEPTION_IF(!crypto::secret_key_to_public_key(spend_secret_key, local_signer), error::invalid_multisig_seed);
   THROW_WALLET_EXCEPTION_IF(std::find(multisig_signers.begin(), multisig_signers.end(), local_signer) == multisig_signers.end(), error::invalid_multisig_seed);
-  rct::key skey = rct::zero();
-  for (const auto &msk: multisig_keys)
-    sc_add(skey.bytes, skey.bytes, rct::sk2rct(msk).bytes);
-  THROW_WALLET_EXCEPTION_IF(!(rct::rct2sk(skey) == spend_secret_key), error::invalid_multisig_seed);
-  memwipe(&skey, sizeof(rct::key));
 
   m_account.make_multisig(view_secret_key, spend_secret_key, spend_public_key, multisig_keys);
 
@@ -4765,6 +4761,8 @@ void wallet2::generate(const std::string& wallet_, const epee::wipeable_string&
   m_multisig = true;
   m_multisig_threshold = threshold;
   m_multisig_signers = multisig_signers;
+  // wallet is assumed already finalized
+  m_multisig_rounds_passed = multisig::multisig_setup_rounds_required(m_multisig_signers.size(), m_multisig_threshold);
   setup_keys(password);
 
   create_keys_file(wallet_, false, password, m_nettype != MAINNET || create_address_file);
@@ -5215,7 +5213,7 @@ bool wallet2::multisig(bool *ready, uint32_t *threshold, uint32_t *total) const
   if (ready)
   {
     *ready = !(get_account().get_keys().m_account_address.m_spend_public_key == rct::rct2pk(rct::identity())) &&
-      (m_multisig_rounds_passed == multisig::multisig_kex_rounds_required(m_multisig_signers.size(), m_multisig_threshold) + 1);
+      (m_multisig_rounds_passed == multisig::multisig_setup_rounds_required(m_multisig_signers.size(), m_multisig_threshold));
   }
   return true;
 }

src/wallet/wallet2.h

@@ -817,7 +817,8 @@ private:
     };
 
     /*!
-     * \brief  Generates a wallet or restores one.
+     * \brief  Generates a wallet or restores one. Assumes the multisig setup
+      *        has already completed for the provided multisig info.
      * \param  wallet_              Name of wallet file
      * \param  password             Password of wallet file
      * \param  multisig_data        The multisig restore info and keys

tests/unit_tests/multisig.cpp

@@ -171,7 +171,7 @@ static void make_wallets(std::vector<tools::wallet2>& wallets, unsigned int M)
 {
   ASSERT_TRUE(wallets.size() > 1 && wallets.size() <= KEYS_COUNT);
   ASSERT_TRUE(M <= wallets.size());
-  std::uint32_t total_rounds_required = multisig::multisig_kex_rounds_required(wallets.size(), M) + 1;
+  std::uint32_t total_rounds_required = multisig::multisig_setup_rounds_required(wallets.size(), M);
   std::uint32_t rounds_complete{0};
 
   // initialize wallets, get first round multisig kex msgs