Merge pull request #38 from wowario/ftl_check_window

Tighten future time limit and timestamp check window

src/cryptonote_config.h

@@ -44,10 +44,12 @@
 #define CURRENT_TRANSACTION_VERSION                     2
 #define CURRENT_BLOCK_MAJOR_VERSION                     7
 #define CURRENT_BLOCK_MINOR_VERSION                     7
+#define CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT_V3           420
 #define CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT_V2           300*2
 #define CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT              60*60*2
 #define CRYPTONOTE_DEFAULT_TX_SPENDABLE_AGE             4
 
+#define BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW_V2            11
 #define BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW               60
 
 // MONEY_SUPPLY - total number coins to be generated

src/cryptonote_core/blockchain.cpp

@@ -1335,11 +1335,12 @@ bool Blockchain::complete_timestamps_vector(uint64_t start_top_height, std::vect
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
 
-  if(timestamps.size() >= BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW)
+  uint64_t blockchain_timestamp_check_window = get_current_hard_fork_version() < 9 ? BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW : BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW_V2;
+  if(timestamps.size() >= blockchain_timestamp_check_window)
     return true;
 
   CRITICAL_REGION_LOCAL(m_blockchain_lock);
-  size_t need_elements = BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW - timestamps.size();
+  size_t need_elements = blockchain_timestamp_check_window - timestamps.size();
   CHECK_AND_ASSERT_MES(start_top_height < m_db->height(), false, "internal error: passed start_height not < " << " m_db->height() -- " << start_top_height << " >= " << m_db->height());
   size_t stop_offset = start_top_height > need_elements ? start_top_height - need_elements : 0;
   while (start_top_height != stop_offset)
@@ -3196,9 +3197,10 @@ bool Blockchain::check_block_timestamp(std::vector<uint64_t>& timestamps, const
   LOG_PRINT_L3("Blockchain::" << __func__);
   uint64_t median_ts = epee::misc_utils::median(timestamps);
 
+  uint64_t blockchain_timestamp_check_window = get_current_hard_fork_version() < 9 ? BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW : BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW_V2;
   if(b.timestamp < median_ts)
   {
-    MERROR_VER("Timestamp of block with id: " << get_block_hash(b) << ", " << b.timestamp << ", less than median of last " << BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW << " blocks, " << median_ts);
+    MERROR_VER("Timestamp of block with id: " << get_block_hash(b) << ", " << b.timestamp << ", less than median of last " << blockchain_timestamp_check_window << " blocks, " << median_ts);
     return false;
   }
 
@@ -3215,15 +3217,16 @@ bool Blockchain::check_block_timestamp(std::vector<uint64_t>& timestamps, const
 bool Blockchain::check_block_timestamp(const block& b) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
-  uint64_t cryptonote_block_future_time_limit = get_current_hard_fork_version() < 7 ? CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT : CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT_V2;
+  uint64_t cryptonote_block_future_time_limit = get_current_hard_fork_version() < 9 ? CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT_V2 : CRYPTONOTE_BLOCK_FUTURE_TIME_LIMIT_V3;
+  uint64_t blockchain_timestamp_check_window = get_current_hard_fork_version() < 9 ? BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW : BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW_V2;
   if(b.timestamp > get_adjusted_time() + cryptonote_block_future_time_limit)
   {
-    MERROR_VER("Timestamp of block with id: " << get_block_hash(b) << ", " << b.timestamp << ", bigger than adjusted time + 2 hours");
+    MERROR_VER("Timestamp of block with id: " << get_block_hash(b) << ", " << b.timestamp << ", bigger than adjusted time + 7 minutes");
     return false;
   }
 
   // if not enough blocks, no proper median yet, return true
-  if(m_db->height() < BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW)
+  if(m_db->height() < blockchain_timestamp_check_window)
   {
     return true;
   }
@@ -3232,7 +3235,7 @@ bool Blockchain::check_block_timestamp(const block& b) const
   auto h = m_db->height();
 
   // need most recent 60 blocks, get index of first of those
-  size_t offset = h - BLOCKCHAIN_TIMESTAMP_CHECK_WINDOW;
+  size_t offset = h - blockchain_timestamp_check_window;
   for(;offset < h; ++offset)
   {
     timestamps.push_back(m_db->get_block_timestamp(offset));