wallet: add shared ring database

This maps key images to rings, so that different forks can reuse
the rings by key image. This avoids revealing the real inputs like
would happen if two forks spent the same outputs with different
rings. This database is meant to be shared with all Monero forks
which don't bother making a new chain, putting users' privacy at
risk in the process. It is placed in a shared data directory by
default ($HOME/.shared-ringdb on UNIX like systems). You may
use --shared-ringdb-dir to override this location, and should
then do so for all Monero forks for them to share the database.

2 files changed, 62 insertions, 0 deletions

diff --git a/src/simplewallet/simplewallet.cpp b/src/simplewallet/simplewallet.cpp
index 8bae1e2c9..3363b84ed 100644
--- a/src/simplewallet/simplewallet.cpp
+++ b/src/simplewallet/simplewallet.cpp
@@ -1294,6 +1294,58 @@ bool simple_wallet::export_raw_multisig(const std::vector<std::string> &args)
   return true;
 }
 
+bool simple_wallet::print_ring(const std::vector<std::string> &args)
+{
+  crypto::key_image key_image;
+  if (args.size() != 1)
+  {
+    fail_msg_writer() << tr("usage: print_ring <key_image>");
+    return true;
+  }
+
+  if (!epee::string_tools::hex_to_pod(args[0], key_image))
+  {
+    fail_msg_writer() << tr("Invalid key image");
+    return true;
+  }
+
+  std::vector<uint64_t> ring;
+  try
+  {
+    if (m_wallet->get_ring(m_wallet->get_ring_database(), key_image, ring))
+    {
+      std::stringstream str;
+      for (const auto &x: ring)
+        str << x << " ";
+      success_msg_writer() << tr("Ring size ") << std::to_string(ring.size()) << ": " << str.str();
+    }
+    else
+    {
+      fail_msg_writer() << tr("Key image either not spent, or spent with mixin 0");
+    }
+  }
+  catch (const std::exception &e)
+  {
+    fail_msg_writer() << tr("Failed to get key image ring: ") << e.what();
+  }
+
+  return true;
+}
+
+bool simple_wallet::save_known_rings(const std::vector<std::string> &args)
+{
+  try
+  {
+    LOCK_IDLE_SCOPE();
+    m_wallet->find_and_save_rings(m_wallet->get_ring_database());
+  }
+  catch (const std::exception &e)
+  {
+    fail_msg_writer() << tr("Failed to save known rings: ") << e.what();
+  }
+  return true;
+}
+
 bool simple_wallet::set_always_confirm_transfers(const std::vector<std::string> &args/* = std::vector<std::string>()*/)
 {
   const auto pwd_container = get_and_verify_password();
@@ -1951,6 +2003,14 @@ simple_wallet::simple_wallet()
                            boost::bind(&simple_wallet::export_raw_multisig, this, _1),
                            tr("export_raw_multisig_tx <filename>"),
                            tr("Export a signed multisig transaction to a file"));
+  m_cmd_binder.set_handler("print_ring",
+                           boost::bind(&simple_wallet::print_ring, this, _1),
+                           tr("print_ring <key_image>"),
+                           tr("Print the ring used to spend a given key image (if the ring size is > 1)"));
+  m_cmd_binder.set_handler("save_known_rings",
+                           boost::bind(&simple_wallet::save_known_rings, this, _1),
+                           tr("save_known_rings"),
+                           tr("Save known rings to the shared rings database"));
   m_cmd_binder.set_handler("help",
                            boost::bind(&simple_wallet::help, this, _1),
                            tr("help [<command>]"),
diff --git a/src/simplewallet/simplewallet.h b/src/simplewallet/simplewallet.h
index 6f344439e..781b74b66 100644
--- a/src/simplewallet/simplewallet.h
+++ b/src/simplewallet/simplewallet.h
@@ -208,6 +208,8 @@ namespace cryptonote
     bool sign_multisig(const std::vector<std::string>& args);
     bool submit_multisig(const std::vector<std::string>& args);
     bool export_raw_multisig(const std::vector<std::string>& args);
+    bool print_ring(const std::vector<std::string>& args);
+    bool save_known_rings(const std::vector<std::string>& args);
 
     uint64_t get_daemon_blockchain_height(std::string& err);
     bool try_connect_to_daemon(bool silent = false, uint32_t* version = nullptr);