From 90c7b5d02da379f60af766729a2ac91fccf974c5 Mon Sep 17 00:00:00 2001
From: cryptozoidberg <crypto.zoidberg@gmail.com>
Date: Sat, 13 Jan 2024 20:24:10 +0100
Subject: [PATCH] hf4 mandatory check for decoy size

---
 src/currency_core/blockchain_storage.cpp    |  5 +++++
 src/currency_core/currency_config.h         |  1 +
 src/currency_core/currency_format_utils.cpp | 19 +++++++++++++++++++
 src/currency_core/currency_format_utils.h   |  1 +
 4 files changed, 26 insertions(+)

diff --git a/src/currency_core/blockchain_storage.cpp b/src/currency_core/blockchain_storage.cpp
index 242aa76b..265113ba 100644
--- a/src/currency_core/blockchain_storage.cpp
+++ b/src/currency_core/blockchain_storage.cpp
@@ -5814,6 +5814,7 @@ bool blockchain_storage::validate_tx_for_hardfork_specific_terms(const transacti
   
   // TODO @#@# consider: 1) tx.proofs, 2) new proof data structures
 
+
   if (var_is_after_hardfork_4_zone)
   {    
     CHECK_AND_ASSERT_MES(tx.version > TRANSACTION_VERSION_PRE_HF4, false, "HF4: tx with version " << tx.version << " is not allowed");
@@ -5825,6 +5826,10 @@ bool blockchain_storage::validate_tx_for_hardfork_specific_terms(const transacti
     {
       return false;
     }
+    uint64_t keys_count = get_hf4_inputs_key_offsets_count(tx); 
+    if (keys_count != 0 && keys_count - 1 < CURRENCY_HF4_MANDATORY_DECOY_SET_SIZE)
+      return false;
+
   }
 
 
diff --git a/src/currency_core/currency_config.h b/src/currency_core/currency_config.h
index 14070d4f..b77791cb 100644
--- a/src/currency_core/currency_config.h
+++ b/src/currency_core/currency_config.h
@@ -37,6 +37,7 @@
 #define CURRENT_BLOCK_MAJOR_VERSION                     3
 
 #define CURRENCY_DEFAULT_DECOY_SET_SIZE                 10
+#define CURRENCY_HF4_MANDATORY_DECOY_SET_SIZE           15
 
 #define CURRENT_BLOCK_MINOR_VERSION                     0
 #define CURRENCY_BLOCK_FUTURE_TIME_LIMIT                60*60*2
diff --git a/src/currency_core/currency_format_utils.cpp b/src/currency_core/currency_format_utils.cpp
index 7797956c..080f251e 100644
--- a/src/currency_core/currency_format_utils.cpp
+++ b/src/currency_core/currency_format_utils.cpp
@@ -3751,6 +3751,25 @@ namespace currency
     return true;
   }
   //---------------------------------------------------------------
+  //if return 0 -> no txin_zc_input seen
+  uint64_t get_hf4_inputs_key_offsets_count(const transaction& tx)
+  {
+    uint64_t key_offsets_count = 0;
+
+    for (const auto& e : tx.vin)
+    {
+      if (e.type() != typeid(txin_zc_input))
+        continue;
+
+      if (boost::get<txin_zc_input>(e).key_offsets.size() > key_offsets_count)
+      {
+        key_offsets_count = boost::get<txin_zc_input>(e).key_offsets.size();
+      }
+    }
+
+    return key_offsets_count;
+  }
+  //---------------------------------------------------------------
   bool check_native_coins_amount_burnt_in_outs(const transaction& tx, const uint64_t amount, uint64_t* p_amount_burnt /* = nullptr */)
   {
     if (tx.version <= TRANSACTION_VERSION_PRE_HF4)
diff --git a/src/currency_core/currency_format_utils.h b/src/currency_core/currency_format_utils.h
index f5b101f9..aa031ce8 100644
--- a/src/currency_core/currency_format_utils.h
+++ b/src/currency_core/currency_format_utils.h
@@ -421,6 +421,7 @@ namespace currency
   bool add_padding_to_tx(transaction& tx, size_t count);
   bool is_service_tx(const transaction& tx);
   bool does_tx_have_only_mixin_inputs(const transaction& tx);
+  uint64_t get_hf4_inputs_key_offsets_count(const transaction& tx);
   bool is_showing_sender_addres(const transaction& tx);
   bool check_native_coins_amount_burnt_in_outs(const transaction& tx, const uint64_t amount, uint64_t* p_amount_burnt = nullptr);
   std::string print_stake_kernel_info(const stake_kernel& sk);