simplewallet: prompt when spending more than one old out in one tx

src/simplewallet/simplewallet.cpp

@@ -92,6 +92,8 @@ typedef cryptonote::simple_wallet sw;
 
 #define MIN_RING_SIZE 11 // Used to inform user about min ring size -- does not track actual protocol
 
+#define OLD_AGE_WARN_THRESHOLD (30 * 86400 / DIFFICULTY_TARGET_V2) // 30 days
+
 #define LOCK_IDLE_SCOPE() \
   bool auto_refresh_enabled = m_auto_refresh_enabled.load(std::memory_order_relaxed); \
   m_auto_refresh_enabled.store(false, std::memory_order_relaxed); \
@@ -5606,6 +5608,43 @@ bool simple_wallet::print_ring_members(const std::vector<tools::wallet2::pending
   return true;
 }
 //----------------------------------------------------------------------------------------------------
+bool simple_wallet::prompt_if_old(const std::vector<tools::wallet2::pending_tx> &ptx_vector)
+{
+  // count the number of old outputs
+  std::string err;
+  uint64_t bc_height = get_daemon_blockchain_height(err);
+  if (!err.empty())
+    return true;
+
+  int max_n_old = 0;
+  for (const auto &ptx: ptx_vector)
+  {
+    int n_old = 0;
+    for (const auto i: ptx.selected_transfers)
+    {
+      const tools::wallet2::transfer_details &td = m_wallet->get_transfer_details(i);
+      uint64_t age = bc_height - td.m_block_height;
+      if (age > OLD_AGE_WARN_THRESHOLD)
+        ++n_old;
+    }
+    max_n_old = std::max(max_n_old, n_old);
+  }
+  if (max_n_old > 1)
+  {
+    std::stringstream prompt;
+    prompt << tr("Transaction spends more than one very old output. Privacy would be better if they were sent separately.");
+    prompt << ENDL << tr("Spend them now anyway?");
+    std::string accepted = input_line(prompt.str(), true);
+    if (std::cin.eof())
+      return false;
+    if (!command_line::is_yes(accepted))
+    {
+      return false;
+    }
+  }
+  return true;
+}
+//----------------------------------------------------------------------------------------------------
 bool simple_wallet::transfer_main(int transfer_type, const std::vector<std::string> &args_, bool called_by_mms)
 {
 //  "transfer [index=<N1>[,<N2>,...]] [<priority>] [<ring_size>] <address> <amount> [<payment_id>]"
@@ -5907,6 +5946,12 @@ bool simple_wallet::transfer_main(int transfer_type, const std::vector<std::stri
       }
     }
 
+    if (!prompt_if_old(ptx_vector))
+    {
+      fail_msg_writer() << tr("transaction cancelled.");
+      return false;
+    }
+
     // if more than one tx necessary, prompt user to confirm
     if (m_wallet->always_confirm_transfers() || ptx_vector.size() > 1)
     {
@@ -6088,7 +6133,8 @@ bool simple_wallet::locked_transfer(const std::vector<std::string> &args_)
 //----------------------------------------------------------------------------------------------------
 bool simple_wallet::locked_sweep_all(const std::vector<std::string> &args_)
 {
-  return sweep_main(0, true, args_);
+  sweep_main(0, true, args_);
+  return true;
 }
 //----------------------------------------------------------------------------------------------------
 
@@ -6408,6 +6454,12 @@ bool simple_wallet::sweep_main(uint64_t below, bool locked, const std::vector<st
       return true;
     }
 
+    if (!prompt_if_old(ptx_vector))
+    {
+      fail_msg_writer() << tr("transaction cancelled.");
+      return false;
+    }
+
     // give user total and fee, and prompt to confirm
     uint64_t total_fee = 0, total_sent = 0;
     for (size_t n = 0; n < ptx_vector.size(); ++n)
@@ -6754,7 +6806,8 @@ bool simple_wallet::sweep_single(const std::vector<std::string> &args_)
 //----------------------------------------------------------------------------------------------------
 bool simple_wallet::sweep_all(const std::vector<std::string> &args_)
 {
-  return sweep_main(0, false, args_);
+  sweep_main(0, false, args_);
+  return true;
 }
 //----------------------------------------------------------------------------------------------------
 bool simple_wallet::sweep_below(const std::vector<std::string> &args_)
@@ -6770,7 +6823,8 @@ bool simple_wallet::sweep_below(const std::vector<std::string> &args_)
     fail_msg_writer() << tr("invalid amount threshold");
     return true;
   }
-  return sweep_main(below, false, std::vector<std::string>(++args_.begin(), args_.end()));
+  sweep_main(below, false, std::vector<std::string>(++args_.begin(), args_.end()));
+  return true;
 }
 //----------------------------------------------------------------------------------------------------
 bool simple_wallet::donate(const std::vector<std::string> &args_)

src/simplewallet/simplewallet.h

@@ -261,6 +261,7 @@ namespace cryptonote
     void on_refresh_finished(uint64_t start_height, uint64_t fetched_blocks, bool is_init, bool received_money);
     std::pair<std::string, std::string> show_outputs_line(const std::vector<uint64_t> &heights, uint64_t blockchain_height, uint64_t highlight_height = std::numeric_limits<uint64_t>::max()) const;
     bool freeze_thaw(const std::vector<std::string>& args, bool freeze);
+    bool prompt_if_old(const std::vector<tools::wallet2::pending_tx> &ptx_vector);
 
     struct transfer_view
     {