wallet2: better test on whether to allow output import

Being offline is not a good enough heuristic, so we keep track
of whether the wallet ever refreshed from a daemon, which is a
lot better, and probably the best we can do without manual user
designation (which would break existing cold wallet setups till
the user designates those wallets)

src/wallet/wallet2.cpp

@@ -1218,7 +1218,8 @@ wallet2::wallet2(network_type nettype, uint64_t kdf_rounds, bool unattended, std
   m_export_format(ExportFormat::Binary),
   m_load_deprecated_formats(false),
   m_credits_target(0),
-  m_enable_multisig(false)
+  m_enable_multisig(false),
+  m_has_ever_refreshed_from_node(false)
 {
   set_rpc_client_secret_key(rct::rct2sk(rct::skGen()));
 }
@@ -3535,6 +3536,8 @@ void wallet2::refresh(bool trusted_daemon, uint64_t start_height, uint64_t & blo
           throw std::runtime_error("proxy exception in refresh thread");
       }
 
+      m_has_ever_refreshed_from_node = true;
+
       if(!first && blocks_start_height == next_blocks_start_height)
       {
         m_node_rpc_proxy.set_height(m_blockchain.size());
@@ -13175,7 +13178,8 @@ size_t wallet2::import_outputs(const std::tuple<uint64_t, uint64_t, std::vector<
 {
   PERF_TIMER(import_outputs);
 
-  THROW_WALLET_EXCEPTION_IF(!m_offline, error::wallet_internal_error, "Hot wallets cannot import outputs");
+  THROW_WALLET_EXCEPTION_IF(m_has_ever_refreshed_from_node, error::wallet_internal_error,
+      "Hot wallets cannot import outputs");
 
   // we can now import piecemeal
   const size_t offset = std::get<0>(outputs);
@@ -13254,7 +13258,8 @@ size_t wallet2::import_outputs(const std::tuple<uint64_t, uint64_t, std::vector<
 {
   PERF_TIMER(import_outputs);
 
-  THROW_WALLET_EXCEPTION_IF(!m_offline, error::wallet_internal_error, "Hot wallets cannot import outputs");
+  THROW_WALLET_EXCEPTION_IF(m_has_ever_refreshed_from_node, error::wallet_internal_error,
+      "Hot wallets cannot import outputs");
 
   // we can now import piecemeal
   const size_t offset = std::get<0>(outputs);

src/wallet/wallet2.h

@@ -1229,11 +1229,17 @@ private:
       if(ver < 29)
         return;
       a & m_rpc_client_secret_key;
+      if(ver < 30)
+      {
+        m_has_ever_refreshed_from_node = false;
+        return;
+      }
+      a & m_has_ever_refreshed_from_node;
     }
 
     BEGIN_SERIALIZE_OBJECT()
       MAGIC_FIELD("monero wallet cache")
-      VERSION_FIELD(0)
+      VERSION_FIELD(1)
       FIELD(m_blockchain)
       FIELD(m_transfers)
       FIELD(m_account_public_address)
@@ -1259,6 +1265,12 @@ private:
       FIELD(m_device_last_key_image_sync)
       FIELD(m_cold_key_images)
       FIELD(m_rpc_client_secret_key)
+      if (version < 1)
+      {
+        m_has_ever_refreshed_from_node = false;
+        return true;
+      }
+      FIELD(m_has_ever_refreshed_from_node)
     END_SERIALIZE()
 
     /*!
@@ -1471,7 +1483,7 @@ private:
 
     // Import/Export wallet data
     std::tuple<uint64_t, uint64_t, std::vector<tools::wallet2::exported_transfer_details>> export_outputs(bool all = false, uint32_t start = 0, uint32_t count = 0xffffffff) const;
-    std::string export_outputs_to_str(bool all = false, uint32_t start = 0, uint32_t count = 0) const;
+    std::string export_outputs_to_str(bool all = false, uint32_t start = 0, uint32_t count = 0xffffffff) const;
     size_t import_outputs(const std::tuple<uint64_t, uint64_t, std::vector<tools::wallet2::exported_transfer_details>> &outputs);
     size_t import_outputs(const std::tuple<uint64_t, uint64_t, std::vector<tools::wallet2::transfer_details>> &outputs);
     size_t import_outputs_from_str(const std::string &outputs_st);
@@ -1906,11 +1918,13 @@ private:
     ExportFormat m_export_format;
     bool m_load_deprecated_formats;
 
+    bool m_has_ever_refreshed_from_node;
+
     static boost::mutex default_daemon_address_lock;
     static std::string default_daemon_address;
   };
 }
-BOOST_CLASS_VERSION(tools::wallet2, 29)
+BOOST_CLASS_VERSION(tools::wallet2, 30)
 BOOST_CLASS_VERSION(tools::wallet2::transfer_details, 12)
 BOOST_CLASS_VERSION(tools::wallet2::multisig_info, 1)
 BOOST_CLASS_VERSION(tools::wallet2::multisig_info::LR, 0)

tests/functional_tests/cold_signing.py

@@ -109,6 +109,15 @@ class ColdSigningTest():
                     num_outputs -= 1
                 count = 1 + int(random.random() * 5)
                 res = self.hot_wallet.export_outputs(all = True, start = start, count = count)
+
+                # the hot wallet cannot import outputs
+                ok = False
+                try:
+                    self.hot_wallet.import_outputs(res.outputs_data_hex)
+                except:
+                    ok = True
+                assert ok
+
                 try:
                     self.cold_wallet.import_outputs(res.outputs_data_hex)
                 except Exception as e: