From 4e115a3a4c1d3b12fe2beca116dd9674ca1d5c06 Mon Sep 17 00:00:00 2001
From: moneromooo-monero <moneromooo-monero@users.noreply.github.com>
Date: Tue, 26 Sep 2017 17:31:15 +0100
Subject: [PATCH] core: remove out sorting from v7 rules

and restore random shuffle of outputs

This turned out to have a flaw (sort order depends on output
index), and this doesn't really bring much anyway
---
 src/cryptonote_core/blockchain.cpp          | 20 --------------------
 src/cryptonote_core/cryptonote_tx_utils.cpp | 21 ++++-----------------
 2 files changed, 4 insertions(+), 37 deletions(-)

diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 0b09d503c..46427d161 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -2383,26 +2383,6 @@ bool Blockchain::check_tx_outputs(const transaction& tx, tx_verification_context
     }
   }
 
-  // from v7, sorted outs
-  if (m_hardfork->get_current_version() >= 7) {
-    const crypto::public_key *last_key = NULL;
-    for (size_t n = 0; n < tx.vout.size(); ++n)
-    {
-      const tx_out &o = tx.vout[n];
-      if (o.target.type() == typeid(txout_to_key))
-      {
-        const txout_to_key& out_to_key = boost::get<txout_to_key>(o.target);
-        if (last_key && memcmp(&out_to_key.key, last_key, sizeof(*last_key)) >= 0)
-        {
-          MERROR_VER("transaction has unsorted outputs");
-          tvc.m_invalid_output = true;
-          return false;
-        }
-        last_key = &out_to_key.key;
-      }
-    }
-  }
-
   return true;
 }
 //------------------------------------------------------------------
diff --git a/src/cryptonote_core/cryptonote_tx_utils.cpp b/src/cryptonote_core/cryptonote_tx_utils.cpp
index 19ed57aba..a5969c6b6 100644
--- a/src/cryptonote_core/cryptonote_tx_utils.cpp
+++ b/src/cryptonote_core/cryptonote_tx_utils.cpp
@@ -264,6 +264,10 @@ namespace cryptonote
       tx.vin.push_back(input_to_key);
     }
 
+    // "Shuffle" outs
+    std::vector<tx_destination_entry> shuffled_dsts(destinations);
+    std::random_shuffle(shuffled_dsts.begin(), shuffled_dsts.end(), [](unsigned int i) { return crypto::rand<unsigned int>() % i; });
+
     // sort ins by their key image
     std::vector<size_t> ins_order(sources.size());
     for (size_t n = 0; n < sources.size(); ++n)
@@ -309,23 +313,6 @@ namespace cryptonote
       summary_outs_money += dst_entr.amount;
     }
 
-#if 0
-    // sort outs by their public key
-    std::vector<size_t> outs_order(tx.vout.size());
-    for (size_t n = 0; n < tx.vout.size(); ++n)
-      outs_order[n] = n;
-    std::sort(outs_order.begin(), outs_order.end(), [&](size_t i0, size_t i1) {
-      const txout_to_key &tk0 = boost::get<txout_to_key>(tx.vout[i0].target);
-      const txout_to_key &tk1 = boost::get<txout_to_key>(tx.vout[i1].target);
-      return memcmp(&tk0.key, &tk1.key, sizeof(tk0.key)) < 0;
-    });
-    tools::apply_permutation(outs_order, [&] (size_t i0, size_t i1) {
-      std::swap(tx.vout[i0], tx.vout[i1]);
-      if (!amount_keys.empty())
-        std::swap(amount_keys[i0], amount_keys[i1]);
-    });
-#endif
-
     //check money
     if(summary_outs_money > summary_inputs_money )
     {