Add a configurable size limit for tx_extra in tx pool

src/cryptonote_basic/verification_context.h

@@ -53,6 +53,7 @@ namespace cryptonote
     bool m_overspend;
     bool m_fee_too_low;
     bool m_too_few_outputs;
+    bool m_tx_extra_too_big;
   };
 
   struct block_verification_context

src/cryptonote_config.h

@@ -206,6 +206,11 @@
 
 #define DNS_BLOCKLIST_LIFETIME (86400 * 8)
 
+//The default limit is enough for the mandatory transaction content with 16 outputs (547 bytes),
+//a custom tag and length (3 bytes) and up to 100 bytes of custom data for each recipient.
+// (1+32) + (1+1+16*32) + (1+2+16*100) = 2150
+#define DEFAULT_TX_EXTRA_MAX_SIZE               2150
+
 // New constants are intended to go here
 namespace config
 {

src/cryptonote_core/cryptonote_core.cpp

@@ -223,6 +223,11 @@ namespace cryptonote
   , "Keep alternative blocks on restart"
   , false
   };
+  static const command_line::arg_descriptor<size_t> arg_max_tx_extra_size  = {
+    "max-tx-extra-size"
+  , "Set the maximum permitted size of tx_extra in bytes (0 = no limit)."
+  , DEFAULT_TX_EXTRA_MAX_SIZE
+  };
 
   //-----------------------------------------------------------------------------------------------
   core::core(i_cryptonote_protocol* pprotocol):
@@ -353,6 +358,7 @@ namespace cryptonote
     command_line::add_arg(desc, arg_reorg_notify);
     command_line::add_arg(desc, arg_block_rate_notify);
     command_line::add_arg(desc, arg_keep_alt_blocks);
+    command_line::add_arg(desc, arg_max_tx_extra_size);
 
     miner::init_options(desc);
     BlockchainDB::init_options(desc);
@@ -487,6 +493,7 @@ namespace cryptonote
     bool prune_blockchain = command_line::get_arg(vm, arg_prune_blockchain);
     bool keep_alt_blocks = command_line::get_arg(vm, arg_keep_alt_blocks);
     bool keep_fakechain = command_line::get_arg(vm, arg_keep_fakechain);
+    size_t max_tx_extra_size = command_line::get_arg(vm, arg_max_tx_extra_size);
 
     boost::filesystem::path folder(m_config_folder);
     if (m_nettype == FAKECHAIN)
@@ -680,7 +687,7 @@ namespace cryptonote
     r = m_blockchain_storage.init(db.release(), m_nettype, m_offline, regtest ? &regtest_test_options : test_options, fixed_difficulty, get_checkpoints);
     CHECK_AND_ASSERT_MES(r, false, "Failed to initialize blockchain storage");
 
-    r = m_mempool.init(max_txpool_weight, m_nettype == FAKECHAIN);
+    r = m_mempool.init(max_txpool_weight, m_nettype == FAKECHAIN, max_tx_extra_size);
     CHECK_AND_ASSERT_MES(r, false, "Failed to initialize memory pool");
 
     // now that we have a valid m_blockchain_storage, we can clean out any

src/cryptonote_core/tx_pool.cpp

@@ -218,6 +218,15 @@ namespace cryptonote
       return false;
     }
 
+    size_t tx_extra_size = tx.extra.size();
+    if (!kept_by_block && m_max_tx_extra_size > 0 && tx_extra_size > m_max_tx_extra_size)
+    {
+      LOG_PRINT_L1("transaction tx-extra is too big: " << tx_extra_size << " bytes, the limit is: " << m_max_tx_extra_size);
+      tvc.m_verifivation_failed = true;
+      tvc.m_tx_extra_too_big = true;
+      return false;
+    }
+
     // if the transaction came from a block popped from the chain,
     // don't check if we have its key images as spent.
     // TODO: Investigate why not?
@@ -1687,12 +1696,13 @@ namespace cryptonote
     return n_removed;
   }
   //---------------------------------------------------------------------------------
-  bool tx_memory_pool::init(size_t max_txpool_weight, bool mine_stem_txes)
+  bool tx_memory_pool::init(size_t max_txpool_weight, bool mine_stem_txes, size_t max_tx_extra_size)
   {
     CRITICAL_REGION_LOCAL(m_transactions_lock);
     CRITICAL_REGION_LOCAL1(m_blockchain);
 
     m_txpool_max_weight = max_txpool_weight ? max_txpool_weight : DEFAULT_TXPOOL_MAX_WEIGHT;
+    m_max_tx_extra_size = max_tx_extra_size;
     m_txs_by_fee_and_receive_time.clear();
     m_spent_key_images.clear();
     m_txpool_weight = 0;

src/cryptonote_core/tx_pool.h

@@ -207,10 +207,11 @@ namespace cryptonote
      *
      * @param max_txpool_weight the max weight in bytes
      * @param mine_stem_txes whether to mine txes in stem relay mode
+     * @param max_tx_extra_size the max size of tx_extra
      *
      * @return true
      */
-    bool init(size_t max_txpool_weight = 0, bool mine_stem_txes = false);
+    bool init(size_t max_txpool_weight = 0, bool mine_stem_txes = false, size_t max_tx_extra_size = 0);
 
     /**
      * @brief attempts to save the transaction pool state to disk
@@ -632,6 +633,7 @@ namespace cryptonote
     size_t m_txpool_max_weight;
     size_t m_txpool_weight;
     bool m_mine_stem_txes;
+    size_t m_max_tx_extra_size;
 
     mutable std::unordered_map<crypto::hash, std::tuple<bool, tx_verification_context, uint64_t, crypto::hash>> m_input_cache;
 

src/rpc/core_rpc_server_commands_defs.h

@@ -88,7 +88,7 @@ namespace cryptonote
 // advance which version they will stop working with
 // Don't go over 32767 for any of these
 #define CORE_RPC_VERSION_MAJOR 3
-#define CORE_RPC_VERSION_MINOR 11
+#define CORE_RPC_VERSION_MINOR 12
 #define MAKE_CORE_RPC_VERSION(major,minor) (((major)<<16)|(minor))
 #define CORE_RPC_VERSION MAKE_CORE_RPC_VERSION(CORE_RPC_VERSION_MAJOR, CORE_RPC_VERSION_MINOR)
 
@@ -592,6 +592,7 @@ namespace cryptonote
       bool fee_too_low;
       bool too_few_outputs;
       bool sanity_check_failed;
+      bool tx_extra_too_big;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE_PARENT(rpc_access_response_base)
@@ -606,6 +607,7 @@ namespace cryptonote
         KV_SERIALIZE(fee_too_low)
         KV_SERIALIZE(too_few_outputs)
         KV_SERIALIZE(sanity_check_failed)
+        KV_SERIALIZE(tx_extra_too_big)
       END_KV_SERIALIZE_MAP()
     };
     typedef epee::misc_utils::struct_init<response_t> response;