Fake outs set is now decided by the wallet

This plugs a privacy leak from the wallet to the daemon,
as the daemon could previously see what input is included
as a transaction input, which the daemon hadn't previously
supplied. Now, the wallet requests a particular set of
outputs, including the real one.

This can result in transactions that can't be accepted if
the wallet happens to select too many outputs with non standard
unlock times. The daemon could know this and select another
output, but the wallet is blind to it. It's currently very
unlikely since I don't think anything uses non default
unlock times. The wallet requests more outputs than necessary
so it can use spares if any of the returns outputs are still
locked. If there are not enough spares to reach the desired
mixin, the transaction will fail.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 36a233ee7..cc6b48b6b 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -1597,6 +1597,25 @@ bool Blockchain::get_random_outs_for_amounts(const COMMAND_RPC_GET_RANDOM_OUTPUT
   return true;
 }
 //------------------------------------------------------------------
+bool Blockchain::get_outs(const COMMAND_RPC_GET_OUTPUTS::request& req, COMMAND_RPC_GET_OUTPUTS::response& res) const
+{
+  LOG_PRINT_L3("Blockchain::" << __func__);
+  CRITICAL_REGION_LOCAL(m_blockchain_lock);
+
+  res.outs.clear();
+  res.outs.reserve(req.outputs.size());
+  for (const auto &i: req.outputs)
+  {
+    // get tx_hash, tx_out_index from DB
+    crypto::public_key key = m_db->get_output_key(i.amount, i.index).pubkey;
+    tx_out_index toi = m_db->get_output_tx_and_index(i.amount, i.index);
+    bool unlocked = is_tx_spendtime_unlocked(m_db->get_tx_unlock_time(toi.first));
+
+    res.outs.push_back({key, unlocked});
+  }
+  return true;
+}
+//------------------------------------------------------------------
 // This function takes a list of block hashes from another node
 // on the network to find where the split point is between us and them.
 // This is used to see what to send another node that needs to sync.