blockchain: skip checking tx semantics in embedded block hash range

If the txes are bad, this'll be picked up by the block hash mismatch
since the tx merkle root is part of the block hash.

src/cryptonote_core/blockchain.cpp

@@ -4154,6 +4154,15 @@ void Blockchain::load_compiled_in_block_hashes()
 }
 #endif
 
+bool Blockchain::is_within_compiled_block_hash_area(uint64_t height) const
+{
+#if defined(PER_BLOCK_CHECKPOINT)
+  return height < m_blocks_hash_check.size();
+#else
+  return false;
+#endif
+}
+
 void Blockchain::lock()
 {
   m_blockchain_lock.lock();

src/cryptonote_core/blockchain.h

@@ -865,6 +865,9 @@ namespace cryptonote
     cryptonote::blobdata get_txpool_tx_blob(const crypto::hash& txid) const;
     bool for_all_txpool_txes(std::function<bool(const crypto::hash&, const txpool_tx_meta_t&, const cryptonote::blobdata*)>, bool include_blob = false) const;
 
+    bool is_within_compiled_block_hash_area(uint64_t height) const;
+    bool is_within_compiled_block_hash_area() const { return is_within_compiled_block_hash_area(m_db->height()); }
+
     void lock();
     void unlock();
 

src/cryptonote_core/cryptonote_core.cpp

@@ -564,7 +564,11 @@ namespace cryptonote
         rv.outPk[n].dest = rct::pk2rct(boost::get<txout_to_key>(tx.vout[n].target).key);
     }
 
-    if(!check_tx_semantic(tx, keeped_by_block))
+    if (keeped_by_block && get_blockchain_storage().is_within_compiled_block_hash_area())
+    {
+      MTRACE("Skipping semantics check for tx kept by block in embedded hash area");
+    }
+    else if(!check_tx_semantic(tx, keeped_by_block))
     {
       LOG_PRINT_L1("WRONG TRANSACTION BLOB, Failed to check tx " << tx_hash << " semantic, rejected");
       tvc.m_verifivation_failed = true;