Add a size limit for tx_extra in tx pool

src/cryptonote_core/cryptonote_tx_utils.cpp

@@ -437,6 +437,8 @@ namespace cryptonote
     if (!sort_tx_extra(tx.extra, tx.extra))
       return false;
 
+    CHECK_AND_ASSERT_MES(tx.extra.size() <= MAX_TX_EXTRA_SIZE, false, "TX extra size (" << tx.extra.size() << ") is greater than max allowed (" << MAX_TX_EXTRA_SIZE << ")");
+
     //check money
     if(summary_outs_money > summary_inputs_money )
     {