From 6137a0b94d86e9f1c3321969da1c74f1d5e72b4f Mon Sep 17 00:00:00 2001
From: moneromooo-monero <moneromooo-monero@users.noreply.github.com>
Date: Tue, 12 Sep 2017 21:41:30 +0100
Subject: blockchain: reject unsorted ins and outs from v7

This ensures no information is leaked by the ordering
---
 src/common/apply_permutation.h         |  9 +++++++-
 src/cryptonote_core/blockchain.cpp     | 39 ++++++++++++++++++++++++++++++++++
 tests/unit_tests/apply_permutation.cpp | 29 +++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/src/common/apply_permutation.h b/src/common/apply_permutation.h
index 4de224690..4fd952686 100644
--- a/src/common/apply_permutation.h
+++ b/src/common/apply_permutation.h
@@ -32,12 +32,18 @@
 
 #include <vector>
 #include <functional>
+#include "misc_log_ex.h"
 
 namespace tools
 {
 
-void apply_permutation(std::vector<size_t> permutation, const std::function<void(size_t, size_t)> &swap)
+template<typename F>
+void apply_permutation(std::vector<size_t> permutation, const F &swap)
 {
+  //sanity check
+  for (size_t n = 0; n < permutation.size(); ++n)
+    CHECK_AND_ASSERT_THROW_MES(std::find(permutation.begin(), permutation.end(), n) != permutation.end(), "Bad permutation");
+
   for (size_t i = 0; i < permutation.size(); ++i)
   {
     size_t current = i;
@@ -55,6 +61,7 @@ void apply_permutation(std::vector<size_t> permutation, const std::function<void
 template<typename T>
 void apply_permutation(const std::vector<size_t> &permutation, std::vector<T> &v)
 {
+  CHECK_AND_ASSERT_THROW_MES(permutation.size() == v.size(), "Mismatched vector sizes");
   apply_permutation(permutation, [&v](size_t i0, size_t i1){ std::swap(v[i0], v[i1]); });
 }
 
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 93a4e26f8..c0d142979 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -2333,6 +2333,26 @@ 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;
 }
 //------------------------------------------------------------------
@@ -2501,6 +2521,25 @@ bool Blockchain::check_tx_inputs(transaction& tx, tx_verification_context &tvc,
     }
   }
 
+  // from v7, sorted ins
+  if (hf_version >= 7) {
+    const crypto::key_image *last_key_image = NULL;
+    for (size_t n = 0; n < tx.vin.size(); ++n)
+    {
+      const txin_v &txin = tx.vin[n];
+      if (txin.type() == typeid(txin_to_key))
+      {
+        const txin_to_key& in_to_key = boost::get<txin_to_key>(txin);
+        if (last_key_image && memcmp(&in_to_key.k_image, last_key_image, sizeof(*last_key_image)) >= 0)
+        {
+          MERROR_VER("transaction has unsorted inputs");
+          tvc.m_verifivation_failed = true;
+          return false;
+        }
+        last_key_image = &in_to_key.k_image;
+      }
+    }
+  }
   auto it = m_check_txin_table.find(tx_prefix_hash);
   if(it == m_check_txin_table.end())
   {
diff --git a/tests/unit_tests/apply_permutation.cpp b/tests/unit_tests/apply_permutation.cpp
index 888a00746..a008b74ee 100644
--- a/tests/unit_tests/apply_permutation.cpp
+++ b/tests/unit_tests/apply_permutation.cpp
@@ -43,3 +43,32 @@ TEST(apply_permutation, reorder)
   tools::apply_permutation({3, 5, 6, 1, 2, 4, 0}, v);
   ASSERT_EQ(v, std::vector<int>({1, 2, 4, 4, 6, 7, 8}));
 }
+
+TEST(apply_permutation, bad_size)
+{
+  std::vector<int> v_large = {8, 4, 6, 1, 7, 2, 4, 9};
+  std::vector<int> v_small = {8, 4, 6, 1, 7, 2};
+  try
+  { 
+    tools::apply_permutation({3, 5, 6, 1, 2, 4, 0}, v_large);
+    ASSERT_FALSE(true);
+  }
+  catch (const std::exception &e) {}
+  try
+  { 
+    tools::apply_permutation({3, 5, 6, 1, 2, 4, 0}, v_small);
+    ASSERT_FALSE(true);
+  }
+  catch (const std::exception &e) {}
+}
+
+TEST(apply_permutation, bad_permutation)
+{
+  std::vector<int> v = {8, 4, 6, 1, 7, 2, 4};
+  try
+  { 
+    tools::apply_permutation({3, 5, 6, 1, 2, 4, 1}, v);
+    ASSERT_FALSE(true);
+  }
+  catch (const std::exception &e) {}
+}
-- 
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