Correct key image check in tx_pool

src/cryptonote_core/tx_pool.cpp

@@ -422,27 +422,18 @@ namespace cryptonote
       CHECKED_GET_SPECIFIC_VARIANT(in, const txin_to_key, txin, false);
       std::unordered_set<crypto::hash>& kei_image_set = m_spent_key_images[txin.k_image];
 
-      /* If any existing key-image in the set is publicly visible AND this is
-         not forcibly "kept_by_block", then fail (duplicate key image). If all
-         existing key images are supposed to be hidden, we silently allow so
-         that the node doesn't leak knowledge of a local/stem tx. */
-      bool visible = false;
+      // Only allow multiple txes per key-image if kept-by-block. Only allow
+      // the same txid if going from local/stem->fluff.
+
       if (tx_relay != relay_method::block)
       {
-        for (const crypto::hash& other_id : kei_image_set)
-          visible |= m_blockchain.txpool_tx_matches_category(other_id, relay_category::legacy);
-      }
-
-      CHECK_AND_ASSERT_MES(!visible, false, "internal error: tx_relay=" << unsigned(tx_relay)
+        const bool one_txid =
+          (kei_image_set.empty() || (kei_image_set.size() == 1 && *(kei_image_set.cbegin()) == id));
+        CHECK_AND_ASSERT_MES(one_txid, false, "internal error: tx_relay=" << unsigned(tx_relay)
                                            << ", kei_image_set.size()=" << kei_image_set.size() << ENDL << "txin.k_image=" << txin.k_image << ENDL
                                            << "tx_id=" << id);
+      }
 
-      /* If adding a tx (hash) that already exists, fail only if the tx has
-         been publicly "broadcast" previously. This way, when a private tx is
-         received for the first time from a remote node, "this" node will
-         respond as-if it were seen for the first time. LMDB does the
-         "hard-check"  on key-images, so the effect is overwriting the existing
-         tx_pool metadata and "first seen" time. */
       const bool new_or_previously_private =
         kei_image_set.insert(id).second ||
         !m_blockchain.txpool_tx_matches_category(id, relay_category::legacy);

tests/core_tests/chaingen_main.cpp

@@ -161,6 +161,7 @@ int main(int argc, char* argv[])
     GENERATE_AND_PLAY(txpool_spend_key_all);
     GENERATE_AND_PLAY(txpool_double_spend_norelay);
     GENERATE_AND_PLAY(txpool_double_spend_local);
+    GENERATE_AND_PLAY(txpool_double_spend_keyimage);
 
     // Double spend
     GENERATE_AND_PLAY(gen_double_spend_in_tx<false>);

tests/core_tests/tx_pool.cpp

@@ -125,10 +125,12 @@ txpool_double_spend_base::txpool_double_spend_base()
   , m_no_relay_hashes()
   , m_all_hashes()
   , m_no_new_index(0)
+  , m_failed_index(0)
   , m_new_timestamp_index(0)
   , m_last_tx(crypto::hash{})
 {
   REGISTER_CALLBACK_METHOD(txpool_double_spend_base, mark_no_new);
+  REGISTER_CALLBACK_METHOD(txpool_double_spend_base, mark_failed);
   REGISTER_CALLBACK_METHOD(txpool_double_spend_base, mark_timestamp_change);
   REGISTER_CALLBACK_METHOD(txpool_double_spend_base, timestamp_change_pause);
   REGISTER_CALLBACK_METHOD(txpool_double_spend_base, check_unchanged);
@@ -143,6 +145,12 @@ bool txpool_double_spend_base::mark_no_new(cryptonote::core& /*c*/, size_t ev_in
   return true;
 }
 
+bool txpool_double_spend_base::mark_failed(cryptonote::core& /*c*/, size_t ev_index, const std::vector<test_event_entry>& /*events*/)
+{
+  m_failed_index = ev_index + 1;
+  return true;
+}
+
 bool txpool_double_spend_base::mark_timestamp_change(cryptonote::core& /*c*/, size_t ev_index, const std::vector<test_event_entry>& /*events*/)
 {
   m_new_timestamp_index = ev_index + 1;
@@ -483,6 +491,8 @@ bool txpool_double_spend_base::check_tx_verification_context(const cryptonote::t
   m_last_tx = cryptonote::get_transaction_hash(tx);
   if (m_no_new_index == event_idx)
     return !tvc.m_verifivation_failed && !tx_added;
+  else if (m_failed_index == event_idx)
+    return tvc.m_verifivation_failed;// && !tx_added;
   else
     return !tvc.m_verifivation_failed && tx_added;
 }
@@ -559,3 +569,45 @@ bool txpool_double_spend_local::generate(std::vector<test_event_entry>& events)
   return true;
 }
 
+bool txpool_double_spend_keyimage::generate(std::vector<test_event_entry>& events) const
+{
+  INIT_MEMPOOL_TEST();
+
+  DO_CALLBACK(events, "check_txpool_spent_keys");
+  SET_EVENT_VISITOR_SETT(events, event_visitor_settings::set_local_relay);
+  DO_CALLBACK(events, "mark_no_new");
+
+  const std::size_t tx_index1 = events.size();
+  MAKE_TX(events, tx_0, miner_account, bob_account, send_amount, blk_0);
+
+  DO_CALLBACK(events, "increase_all_tx_count");
+  DO_CALLBACK(events, "check_txpool_spent_keys");
+  DO_CALLBACK(events, "mark_timestamp_change");
+  DO_CALLBACK(events, "check_new_hidden");
+  DO_CALLBACK(events, "timestamp_change_pause");
+  DO_CALLBACK(events, "mark_no_new");
+  const std::size_t tx_index2 = events.size();
+  events.push_back(tx_0);
+  DO_CALLBACK(events, "check_txpool_spent_keys");
+  DO_CALLBACK(events, "mark_timestamp_change");
+  DO_CALLBACK(events, "check_unchanged");
+
+  // use same key image with different id
+  cryptonote::transaction tx_1;
+  {
+    auto events_copy = events;
+    events_copy.erase(events_copy.begin() + tx_index1);
+    events_copy.erase(events_copy.begin() + tx_index2 - 1);
+    MAKE_TX(events_copy, tx_temp, miner_account, bob_account, send_amount, blk_0);
+    tx_1 = tx_temp;
+  }
+
+  // same key image
+  DO_CALLBACK(events, "timestamp_change_pause");
+  DO_CALLBACK(events, "mark_failed");
+  events.push_back(tx_1);
+  DO_CALLBACK(events, "check_unchanged");
+
+  return true;
+}
+

tests/core_tests/tx_pool.h

@@ -77,6 +77,7 @@ class txpool_double_spend_base : public txpool_base
   std::unordered_set<crypto::hash> m_no_relay_hashes;
   std::unordered_map<crypto::hash, uint64_t> m_all_hashes;
   size_t m_no_new_index;
+  size_t m_failed_index;
   size_t m_new_timestamp_index;
   crypto::hash m_last_tx;
 
@@ -86,6 +87,7 @@ public:
   txpool_double_spend_base();
 
   bool mark_no_new(cryptonote::core& c, size_t ev_index, const std::vector<test_event_entry>& events);
+  bool mark_failed(cryptonote::core& c, size_t ev_index, const std::vector<test_event_entry>& events);
   bool mark_timestamp_change(cryptonote::core& c, size_t ev_index, const std::vector<test_event_entry>& events);
 
   //! Pause for 1 second, so that `receive_time` for tx meta changes (tx hidden from public rpc being updated)
@@ -116,3 +118,12 @@ struct txpool_double_spend_local : txpool_double_spend_base
 
   bool generate(std::vector<test_event_entry>& events) const;
 };
+
+struct txpool_double_spend_keyimage : txpool_double_spend_base
+{
+  txpool_double_spend_keyimage()
+    : txpool_double_spend_base()
+  {}
+
+  bool generate(std::vector<test_event_entry>& events) const;
+};