rpc: new sanity check on relayed transactions

This will weed out some transactions with silly rings

6 files changed, 152 insertions, 0 deletions

diff --git a/src/cryptonote_core/CMakeLists.txt b/src/cryptonote_core/CMakeLists.txt
index fb96de226..2cbe89b01 100644
--- a/src/cryptonote_core/CMakeLists.txt
+++ b/src/cryptonote_core/CMakeLists.txt
@@ -30,6 +30,7 @@ set(cryptonote_core_sources
   blockchain.cpp
   cryptonote_core.cpp
   tx_pool.cpp
+  tx_sanity_check.cpp
   cryptonote_tx_utils.cpp)
 
 set(cryptonote_core_headers)
@@ -39,6 +40,7 @@ set(cryptonote_core_private_headers
   blockchain.h
   cryptonote_core.h
   tx_pool.h
+  tx_sanity_check.h
   cryptonote_tx_utils.h)
 
 monero_private_headers(cryptonote_core
diff --git a/src/cryptonote_core/tx_sanity_check.cpp b/src/cryptonote_core/tx_sanity_check.cpp
new file mode 100644
index 000000000..d3b225f1c
--- /dev/null
+++ b/src/cryptonote_core/tx_sanity_check.cpp
@@ -0,0 +1,100 @@
+// Copyright (c) 2019, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <stdint.h>
+#include <vector>
+#include "cryptonote_basic/cryptonote_basic_impl.h"
+#include "cryptonote_basic/cryptonote_format_utils.h"
+#include "blockchain.h"
+#include "tx_sanity_check.h"
+
+#undef MONERO_DEFAULT_LOG_CATEGORY
+#define MONERO_DEFAULT_LOG_CATEGORY "txsanity"
+
+namespace cryptonote
+{
+
+bool tx_sanity_check(Blockchain &blockchain, const cryptonote::blobdata &tx_blob)
+{
+  cryptonote::transaction tx;
+
+  if (!cryptonote::parse_and_validate_tx_from_blob(tx_blob, tx))
+  {
+    MERROR("Failed to parse transaction");
+    return false;
+  }
+
+  if (cryptonote::is_coinbase(tx))
+  {
+    MERROR("Transaction is coinbase");
+    return false;
+  }
+  std::set<uint64_t> rct_indices;
+  size_t n_indices = 0;
+
+  for (const auto &txin : tx.vin)
+  {
+    if (txin.type() != typeid(cryptonote::txin_to_key))
+      continue;
+    const cryptonote::txin_to_key &in_to_key = boost::get<cryptonote::txin_to_key>(txin);
+    if (in_to_key.amount != 0)
+      continue;
+    const std::vector<uint64_t> absolute = cryptonote::relative_output_offsets_to_absolute(in_to_key.key_offsets);
+    for (uint64_t offset: absolute)
+      rct_indices.insert(offset);
+    n_indices += in_to_key.key_offsets.size();
+  }
+
+  if (n_indices <= 10)
+  {
+    MERROR("n_indices is only " << n_indices);
+    return true;
+  }
+
+  uint64_t n_available = blockchain.get_num_mature_outputs(0);
+  if (n_available < 10000)
+    return true;
+
+  if (rct_indices.size() < n_indices * 9 / 10)
+  {
+    MERROR("unique indices is only " << rct_indices.size() << "/" << n_indices);
+    return false;
+  }
+
+  std::vector<uint64_t> offsets(rct_indices.begin(), rct_indices.end());
+  uint64_t median = epee::misc_utils::median(offsets);
+  if (median < n_available * 9 / 10)
+  {
+    MERROR("median is " << median << "/" << n_available);
+    return false;
+  }
+
+  return true;
+}
+
+}
diff --git a/src/cryptonote_core/tx_sanity_check.h b/src/cryptonote_core/tx_sanity_check.h
new file mode 100644
index 000000000..c12d1b0b1
--- /dev/null
+++ b/src/cryptonote_core/tx_sanity_check.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2019, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "cryptonote_basic/blobdatatype.h"
+
+namespace cryptonote
+{
+  class Blockchain;
+
+  bool tx_sanity_check(Blockchain &blockchain, const cryptonote::blobdata &tx_blob);
+}
diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index 71bfcc950..97c5015ca 100644
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -41,6 +41,7 @@ using namespace epee;
 #include "cryptonote_basic/cryptonote_format_utils.h"
 #include "cryptonote_basic/account.h"
 #include "cryptonote_basic/cryptonote_basic_impl.h"
+#include "cryptonote_core/tx_sanity_check.h"
 #include "misc_language.h"
 #include "net/parse.h"
 #include "storages/http_abstract_invoke.h"
@@ -844,6 +845,14 @@ namespace cryptonote
       return true;
     }
 
+    if (req.do_sanity_checks && !cryptonote::tx_sanity_check(m_core.get_blockchain_storage(), tx_blob))
+    {
+      res.status = "Failed";
+      res.reason = "Sanity check failed";
+      res.sanity_check_failed = true;
+      return true;
+    }
+
     cryptonote_connection_context fake_context = AUTO_VAL_INIT(fake_context);
     tx_verification_context tvc = AUTO_VAL_INIT(tvc);
     if(!m_core.handle_incoming_tx(tx_blob, tvc, false, false, req.do_not_relay) || tvc.m_verifivation_failed)
diff --git a/src/rpc/core_rpc_server_commands_defs.h b/src/rpc/core_rpc_server_commands_defs.h
index d2aba8d67..a1e2fdf8d 100644
--- a/src/rpc/core_rpc_server_commands_defs.h
+++ b/src/rpc/core_rpc_server_commands_defs.h
@@ -577,10 +577,12 @@ namespace cryptonote
     {
       std::string tx_as_hex;
       bool do_not_relay;
+      bool do_sanity_checks;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(tx_as_hex)
         KV_SERIALIZE_OPT(do_not_relay, false)
+        KV_SERIALIZE_OPT(do_sanity_checks, true)
       END_KV_SERIALIZE_MAP()
     };
     typedef epee::misc_utils::struct_init<request_t> request;
@@ -599,6 +601,7 @@ namespace cryptonote
       bool overspend;
       bool fee_too_low;
       bool not_rct;
+      bool sanity_check_failed;
       bool untrusted;
 
       BEGIN_KV_SERIALIZE_MAP()
@@ -613,6 +616,7 @@ namespace cryptonote
         KV_SERIALIZE(overspend)
         KV_SERIALIZE(fee_too_low)
         KV_SERIALIZE(not_rct)
+        KV_SERIALIZE(sanity_check_failed)
         KV_SERIALIZE(untrusted)
       END_KV_SERIALIZE_MAP()
     };
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index dfcc61426..b74742c6a 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -5988,6 +5988,7 @@ void wallet2::commit_tx(pending_tx& ptx)
     COMMAND_RPC_SEND_RAW_TX::request req;
     req.tx_as_hex = epee::string_tools::buff_to_hex_nodelimer(tx_to_blob(ptx.tx));
     req.do_not_relay = false;
+    req.do_sanity_checks = true;
     COMMAND_RPC_SEND_RAW_TX::response daemon_send_resp;
     m_daemon_rpc_mutex.lock();
     bool r = epee::net_utils::invoke_http_json("/sendrawtransaction", req, daemon_send_resp, m_http_client, rpc_timeout);