From e7197602539b79baa14350bb9e99c935dfbebb72 Mon Sep 17 00:00:00 2001
From: Lee Clagett <code@leeclagett.com>
Date: Tue, 10 Mar 2020 22:30:07 -0400
Subject: [PATCH] Fix receive order leakage with tx fluffing

---
 src/cryptonote_protocol/levin_notify.cpp |  3 +++
 tests/unit_tests/levin.cpp               | 20 ++++++++++++--------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/cryptonote_protocol/levin_notify.cpp b/src/cryptonote_protocol/levin_notify.cpp
index e45c34e02..5abd0d506 100644
--- a/src/cryptonote_protocol/levin_notify.cpp
+++ b/src/cryptonote_protocol/levin_notify.cpp
@@ -358,7 +358,10 @@ namespace levin
         });
 
         for (auto& connection : connections)
+        {
+          std::sort(connection.first.begin(), connection.first.end()); // don't leak receive order
           make_payload_send_txs(*zone_->p2p, std::move(connection.first), connection.second, zone_->pad_txs);
+        }
 
         if (next_flush != std::chrono::steady_clock::time_point::max())
           fluff_flush::queue(std::move(zone_), next_flush);
diff --git a/tests/unit_tests/levin.cpp b/tests/unit_tests/levin.cpp
index 38707f075..720103e5a 100644
--- a/tests/unit_tests/levin.cpp
+++ b/tests/unit_tests/levin.cpp
@@ -462,8 +462,8 @@ TEST_F(levin_notify, fluff_without_padding)
     }
 
     std::vector<cryptonote::blobdata> txs(2);
-    txs[0].resize(100, 'e');
-    txs[1].resize(200, 'f');
+    txs[0].resize(100, 'f');
+    txs[1].resize(200, 'e');
 
     ASSERT_EQ(10u, contexts_.size());
     {
@@ -479,6 +479,7 @@ TEST_F(levin_notify, fluff_without_padding)
         for (++context; context != contexts_.end(); ++context)
             EXPECT_EQ(1u, context->process_send_queue());
 
+        std::sort(txs.begin(), txs.end());
         ASSERT_EQ(9u, receiver_.notified_size());
         for (unsigned count = 0; count < 9; ++count)
         {
@@ -510,8 +511,8 @@ TEST_F(levin_notify, fluff_with_padding)
     }
 
     std::vector<cryptonote::blobdata> txs(2);
-    txs[0].resize(100, 'e');
-    txs[1].resize(200, 'f');
+    txs[0].resize(100, 'f');
+    txs[1].resize(200, 'e');
 
     ASSERT_EQ(10u, contexts_.size());
     {
@@ -527,6 +528,7 @@ TEST_F(levin_notify, fluff_with_padding)
         for (++context; context != contexts_.end(); ++context)
             EXPECT_EQ(1u, context->process_send_queue());
 
+        std::sort(txs.begin(), txs.end());
         ASSERT_EQ(9u, receiver_.notified_size());
         for (unsigned count = 0; count < 9; ++count)
         {
@@ -558,8 +560,8 @@ TEST_F(levin_notify, private_fluff_without_padding)
     }
 
     std::vector<cryptonote::blobdata> txs(2);
-    txs[0].resize(100, 'e');
-    txs[1].resize(200, 'f');
+    txs[0].resize(100, 'f');
+    txs[1].resize(200, 'e');
 
     ASSERT_EQ(10u, contexts_.size());
     {
@@ -572,6 +574,7 @@ TEST_F(levin_notify, private_fluff_without_padding)
         io_service_.reset();
         ASSERT_LT(0u, io_service_.poll());
 
+        std::sort(txs.begin(), txs.end());
         EXPECT_EQ(0u, context->process_send_queue());
         for (++context; context != contexts_.end(); ++context)
         {
@@ -610,8 +613,8 @@ TEST_F(levin_notify, private_fluff_with_padding)
     }
 
     std::vector<cryptonote::blobdata> txs(2);
-    txs[0].resize(100, 'e');
-    txs[1].resize(200, 'f');
+    txs[0].resize(100, 'f');
+    txs[1].resize(200, 'e');
 
     ASSERT_EQ(10u, contexts_.size());
     {
@@ -624,6 +627,7 @@ TEST_F(levin_notify, private_fluff_with_padding)
         io_service_.reset();
         ASSERT_LT(0u, io_service_.poll());
 
+        std::sort(txs.begin(), txs.end());
         EXPECT_EQ(0u, context->process_send_queue());
         for (++context; context != contexts_.end(); ++context)
         {