epee: add SSL support

RPC connections now have optional tranparent SSL.

An optional private key and certificate file can be passed,
using the --{rpc,daemon}-ssl-private-key and
--{rpc,daemon}-ssl-certificate options. Those have as
argument a path to a PEM format private private key and
certificate, respectively.
If not given, a temporary self signed certificate will be used.

SSL can be enabled or disabled using --{rpc}-ssl, which
accepts autodetect (default), disabled or enabled.

Access can be restricted to particular certificates using the
--rpc-ssl-allowed-certificates, which takes a list of
paths to PEM encoded certificates. This can allow a wallet to
connect to only the daemon they think they're connected to,
by forcing SSL and listing the paths to the known good
certificates.

To generate long term certificates:

openssl genrsa -out /tmp/KEY 4096
openssl req -new -key /tmp/KEY -out /tmp/REQ
openssl x509 -req -days 999999 -sha256 -in /tmp/REQ -signkey /tmp/KEY -out /tmp/CERT

/tmp/KEY is the private key, and /tmp/CERT is the certificate,
both in PEM format. /tmp/REQ can be removed. Adjust the last
command to set expiration date, etc, as needed. It doesn't
make a whole lot of sense for monero anyway, since most servers
will run with one time temporary self signed certificates anyway.

SSL support is transparent, so all communication is done on the
existing ports, with SSL autodetection. This means you can start
using an SSL daemon now, but you should not enforce SSL yet or
nothing will talk to you.

4 files changed, 80 insertions, 12 deletions

diff --git a/src/wallet/api/wallet.cpp b/src/wallet/api/wallet.cpp
index 935a8d51c..2b7853330 100644
--- a/src/wallet/api/wallet.cpp
+++ b/src/wallet/api/wallet.cpp
@@ -1924,7 +1924,7 @@ bool WalletImpl::verifyMessageWithPublicKey(const std::string &message, const st
 
 bool WalletImpl::connectToDaemon()
 {
-    bool result = m_wallet->check_connection(NULL, DEFAULT_CONNECTION_TIMEOUT_MILLIS);
+    bool result = m_wallet->check_connection(NULL, NULL, DEFAULT_CONNECTION_TIMEOUT_MILLIS);
     if (!result) {
         setStatusError("Error connecting to daemon at " + m_wallet->get_daemon_address());
     } else {
@@ -1937,7 +1937,7 @@ bool WalletImpl::connectToDaemon()
 Wallet::ConnectionStatus WalletImpl::connected() const
 {
     uint32_t version = 0;
-    m_is_connected = m_wallet->check_connection(&version, DEFAULT_CONNECTION_TIMEOUT_MILLIS);
+    m_is_connected = m_wallet->check_connection(&version, NULL, DEFAULT_CONNECTION_TIMEOUT_MILLIS);
     if (!m_is_connected)
         return Wallet::ConnectionStatus_Disconnected;
     // Version check is not implemented in light wallets nodes/wallets
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index c02d10ab4..ac405157f 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -237,6 +237,11 @@ struct options {
   const command_line::arg_descriptor<std::string> password_file = {"password-file", tools::wallet2::tr("Wallet password file"), "", true};
   const command_line::arg_descriptor<int> daemon_port = {"daemon-port", tools::wallet2::tr("Use daemon instance at port <arg> instead of 18081"), 0};
   const command_line::arg_descriptor<std::string> daemon_login = {"daemon-login", tools::wallet2::tr("Specify username[:password] for daemon RPC client"), "", true};
+  const command_line::arg_descriptor<std::string> daemon_ssl = {"daemon-ssl", tools::wallet2::tr("Enable SSL on daemon RPC connections: enabled|disabled|autodetect"), "autodetect"};
+  const command_line::arg_descriptor<std::string> daemon_ssl_private_key = {"daemon-ssl-private-key", tools::wallet2::tr("Path to a PEM format private key"), ""};
+  const command_line::arg_descriptor<std::string> daemon_ssl_certificate = {"daemon-ssl-certificate", tools::wallet2::tr("Path to a PEM format certificate"), ""};
+  const command_line::arg_descriptor<std::vector<std::string>> daemon_ssl_allowed_certificates = {"daemon-ssl-allowed-certificates", tools::wallet2::tr("List of paths to PEM format certificates of allowed RPC servers")};
+  const command_line::arg_descriptor<bool> daemon_ssl_allow_any_cert = {"daemon-ssl-allow-any-cert", tools::wallet2::tr("Allow any SSL certificate from the daemon"), false};
   const command_line::arg_descriptor<bool> testnet = {"testnet", tools::wallet2::tr("For testnet. Daemon must also be launched with --testnet flag"), false};
   const command_line::arg_descriptor<bool> stagenet = {"stagenet", tools::wallet2::tr("For stagenet. Daemon must also be launched with --stagenet flag"), false};
   const command_line::arg_descriptor<std::string, false, true, 2> shared_ringdb_dir = {
@@ -308,6 +313,14 @@ std::unique_ptr<tools::wallet2> make_basic(const boost::program_options::variabl
   auto daemon_port = command_line::get_arg(vm, opts.daemon_port);
   auto device_name = command_line::get_arg(vm, opts.hw_device);
   auto device_derivation_path = command_line::get_arg(vm, opts.hw_device_derivation_path);
+  auto daemon_ssl_private_key = command_line::get_arg(vm, opts.daemon_ssl_private_key);
+  auto daemon_ssl_certificate = command_line::get_arg(vm, opts.daemon_ssl_certificate);
+  auto daemon_ssl_allowed_certificates = command_line::get_arg(vm, opts.daemon_ssl_allowed_certificates);
+  auto daemon_ssl_allow_any_cert = command_line::get_arg(vm, opts.daemon_ssl_allow_any_cert);
+  auto daemon_ssl = command_line::get_arg(vm, opts.daemon_ssl);
+  epee::net_utils::ssl_support_t ssl_support;
+  THROW_WALLET_EXCEPTION_IF(!epee::net_utils::ssl_support_from_string(ssl_support, daemon_ssl), tools::error::wallet_internal_error,
+      tools::wallet2::tr("Invalid argument for ") + std::string(opts.daemon_ssl.name));
 
   THROW_WALLET_EXCEPTION_IF(!daemon_address.empty() && !daemon_host.empty() && 0 != daemon_port,
       tools::error::wallet_internal_error, tools::wallet2::tr("can't specify daemon host or port more than once"));
@@ -358,8 +371,20 @@ std::unique_ptr<tools::wallet2> make_basic(const boost::program_options::variabl
     catch (const std::exception &e) { }
   }
 
+  std::list<std::string> ssl_allowed_certificates;
+  for (const std::string &path: daemon_ssl_allowed_certificates)
+  {
+      ssl_allowed_certificates.push_back({});
+      if (!epee::file_io_utils::load_file_to_string(path, ssl_allowed_certificates.back()))
+      {
+        MERROR("Failed to load certificate: " << path);
+        ssl_allowed_certificates.back() = std::string();
+      }
+  }
+
   std::unique_ptr<tools::wallet2> wallet(new tools::wallet2(nettype, kdf_rounds, unattended));
-  wallet->init(std::move(daemon_address), std::move(login), 0, false, *trusted_daemon);
+  wallet->init(std::move(daemon_address), std::move(login), 0, *trusted_daemon, ssl_support, std::make_pair(daemon_ssl_private_key, daemon_ssl_certificate), ssl_allowed_certificates, daemon_ssl_allow_any_cert);
+
   boost::filesystem::path ringdb_path = command_line::get_arg(vm, opts.shared_ringdb_dir);
   wallet->set_ring_database(ringdb_path.string());
   wallet->get_message_store().set_options(vm);
@@ -1015,6 +1040,11 @@ void wallet2::init_options(boost::program_options::options_description& desc_par
   command_line::add_arg(desc_params, opts.password_file);
   command_line::add_arg(desc_params, opts.daemon_port);
   command_line::add_arg(desc_params, opts.daemon_login);
+  command_line::add_arg(desc_params, opts.daemon_ssl);
+  command_line::add_arg(desc_params, opts.daemon_ssl_private_key);
+  command_line::add_arg(desc_params, opts.daemon_ssl_certificate);
+  command_line::add_arg(desc_params, opts.daemon_ssl_allowed_certificates);
+  command_line::add_arg(desc_params, opts.daemon_ssl_allow_any_cert);
   command_line::add_arg(desc_params, opts.testnet);
   command_line::add_arg(desc_params, opts.stagenet);
   command_line::add_arg(desc_params, opts.shared_ringdb_dir);
@@ -1066,7 +1096,7 @@ std::unique_ptr<wallet2> wallet2::make_dummy(const boost::program_options::varia
 }
 
 //----------------------------------------------------------------------------------------------------
-bool wallet2::init(std::string daemon_address, boost::optional<epee::net_utils::http::login> daemon_login, uint64_t upper_transaction_weight_limit, bool ssl, bool trusted_daemon)
+bool wallet2::init(std::string daemon_address, boost::optional<epee::net_utils::http::login> daemon_login, uint64_t upper_transaction_weight_limit, bool trusted_daemon, epee::net_utils::ssl_support_t ssl_support, const std::pair<std::string, std::string> &private_key_and_certificate_path, const std::list<std::string> &allowed_certificates, bool allow_any_cert)
 {
   m_checkpoints.init_default_checkpoints(m_nettype);
   if(m_http_client.is_connected())
@@ -1076,8 +1106,7 @@ bool wallet2::init(std::string daemon_address, boost::optional<epee::net_utils::
   m_daemon_address = std::move(daemon_address);
   m_daemon_login = std::move(daemon_login);
   m_trusted_daemon = trusted_daemon;
-  // When switching from light wallet to full wallet, we need to reset the height we got from lw node.
-  return m_http_client.set_server(get_daemon_address(), get_daemon_login(), ssl);
+  return m_http_client.set_server(get_daemon_address(), get_daemon_login(), ssl_support, private_key_and_certificate_path, allowed_certificates, allow_any_cert);
 }
 //----------------------------------------------------------------------------------------------------
 bool wallet2::is_deterministic() const
@@ -4848,7 +4877,7 @@ bool wallet2::prepare_file_names(const std::string& file_path)
   return true;
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::check_connection(uint32_t *version, uint32_t timeout)
+bool wallet2::check_connection(uint32_t *version, bool *ssl, uint32_t timeout)
 {
   THROW_WALLET_EXCEPTION_IF(!m_is_initialized, error::wallet_not_initialized);
 
@@ -4856,15 +4885,20 @@ bool wallet2::check_connection(uint32_t *version, uint32_t timeout)
 
   // TODO: Add light wallet version check.
   if(m_light_wallet) {
-      version = 0;
+      if (version)
+        *version = 0;
+      if (ssl)
+        *ssl = m_light_wallet_connected; // light wallet is always SSL
       return m_light_wallet_connected;
   }
 
-  if(!m_http_client.is_connected())
+  if(!m_http_client.is_connected(ssl))
   {
     m_node_rpc_proxy.invalidate();
     if (!m_http_client.connect(std::chrono::milliseconds(timeout)))
       return false;
+    if(!m_http_client.is_connected(ssl))
+      return false;
   }
 
   if (version)
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index 3b2dd6076..83ad7e56b 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -676,7 +676,11 @@ namespace tools
 
     bool deinit();
     bool init(std::string daemon_address = "http://localhost:8080",
-      boost::optional<epee::net_utils::http::login> daemon_login = boost::none, uint64_t upper_transaction_weight_limit = 0, bool ssl = false, bool trusted_daemon = false);
+      boost::optional<epee::net_utils::http::login> daemon_login = boost::none, uint64_t upper_transaction_weight_limit = 0,
+      bool trusted_daemon = true,
+      epee::net_utils::ssl_support_t ssl_support = epee::net_utils::ssl_support_t::e_ssl_support_autodetect,
+      const std::pair<std::string, std::string> &private_key_and_certificate_path = {},
+      const std::list<std::string> &allowed_certificates = {}, bool allow_any_cert = false);
 
     void stop() { m_run.store(false, std::memory_order_relaxed); m_message_store.stop(); }
 
@@ -800,7 +804,7 @@ namespace tools
     bool sign_multisig_tx_to_file(multisig_tx_set &exported_txs, const std::string &filename, std::vector<crypto::hash> &txids);
     std::vector<pending_tx> create_unmixable_sweep_transactions();
     void discard_unmixable_outputs();
-    bool check_connection(uint32_t *version = NULL, uint32_t timeout = 200000);
+    bool check_connection(uint32_t *version = NULL, bool *ssl = NULL, uint32_t timeout = 200000);
     void get_transfers(wallet2::transfer_container& incoming_transfers) const;
     void get_payments(const crypto::hash& payment_id, std::list<wallet2::payment_details>& payments, uint64_t min_height = 0, const boost::optional<uint32_t>& subaddr_account = boost::none, const std::set<uint32_t>& subaddr_indices = {}) const;
     void get_payments(std::list<std::pair<crypto::hash,wallet2::payment_details>>& payments, uint64_t min_height, uint64_t max_height = (uint64_t)-1, const boost::optional<uint32_t>& subaddr_account = boost::none, const std::set<uint32_t>& subaddr_indices = {}) const;
diff --git a/src/wallet/wallet_rpc_server.cpp b/src/wallet/wallet_rpc_server.cpp
index c87c2fca6..fd95c19a9 100644
--- a/src/wallet/wallet_rpc_server.cpp
+++ b/src/wallet/wallet_rpc_server.cpp
@@ -63,6 +63,10 @@ namespace
   const command_line::arg_descriptor<bool> arg_restricted = {"restricted-rpc", "Restricts to view-only commands", false};
   const command_line::arg_descriptor<std::string> arg_wallet_dir = {"wallet-dir", "Directory for newly created wallets"};
   const command_line::arg_descriptor<bool> arg_prompt_for_password = {"prompt-for-password", "Prompts for password when not provided", false};
+  const command_line::arg_descriptor<std::string> arg_rpc_ssl = {"rpc-ssl", tools::wallet2::tr("Enable SSL on wallet RPC connections: enabled|disabled|autodetect"), "autodetect"};
+  const command_line::arg_descriptor<std::string> arg_rpc_ssl_private_key = {"rpc-ssl-private-key", tools::wallet2::tr("Path to a PEM format private key"), ""};
+  const command_line::arg_descriptor<std::string> arg_rpc_ssl_certificate = {"rpc-ssl-certificate", tools::wallet2::tr("Path to a PEM format certificate"), ""};
+  const command_line::arg_descriptor<std::vector<std::string>> arg_rpc_ssl_allowed_certificates = {"rpc-ssl-allowed-certificates", tools::wallet2::tr("List of paths to PEM format certificates of allowed RPC servers (all allowed if empty)")};
 
   constexpr const char default_rpc_username[] = "monero";
 
@@ -233,10 +237,32 @@ namespace tools
       assert(bool(http_login));
     } // end auth enabled
 
+    auto rpc_ssl_private_key = command_line::get_arg(vm, arg_rpc_ssl_private_key);
+    auto rpc_ssl_certificate = command_line::get_arg(vm, arg_rpc_ssl_certificate);
+    auto rpc_ssl_allowed_certificates = command_line::get_arg(vm, arg_rpc_ssl_allowed_certificates);
+    auto rpc_ssl = command_line::get_arg(vm, arg_rpc_ssl);
+    epee::net_utils::ssl_support_t rpc_ssl_support;
+    if (!epee::net_utils::ssl_support_from_string(rpc_ssl_support, rpc_ssl))
+    {
+      MERROR("Invalid argument for " << std::string(arg_rpc_ssl.name));
+      return false;
+    }
+    std::list<std::string> allowed_certificates;
+    for (const std::string &path: rpc_ssl_allowed_certificates)
+    {
+        allowed_certificates.push_back({});
+        if (!epee::file_io_utils::load_file_to_string(path, allowed_certificates.back()))
+        {
+          MERROR("Failed to load certificate: " << path);
+          allowed_certificates.back() = std::string();
+        }
+    }
+
     m_net_server.set_threads_prefix("RPC");
     auto rng = [](size_t len, uint8_t *ptr) { return crypto::rand(len, ptr); };
     return epee::http_server_impl_base<wallet_rpc_server, connection_context>::init(
-      rng, std::move(bind_port), std::move(rpc_config->bind_ip), std::move(rpc_config->access_control_origins), std::move(http_login)
+      rng, std::move(bind_port), std::move(rpc_config->bind_ip), std::move(rpc_config->access_control_origins), std::move(http_login),
+      rpc_ssl_support, std::make_pair(rpc_ssl_private_key, rpc_ssl_certificate), allowed_certificates
     );
   }
   //------------------------------------------------------------------------------------------------------------------------------
@@ -3937,6 +3963,10 @@ int main(int argc, char** argv) {
   command_line::add_arg(desc_params, arg_from_json);
   command_line::add_arg(desc_params, arg_wallet_dir);
   command_line::add_arg(desc_params, arg_prompt_for_password);
+  command_line::add_arg(desc_params, arg_rpc_ssl);
+  command_line::add_arg(desc_params, arg_rpc_ssl_private_key);
+  command_line::add_arg(desc_params, arg_rpc_ssl_certificate);
+  command_line::add_arg(desc_params, arg_rpc_ssl_allowed_certificates);
 
   daemonizer::init_options(hidden_options, desc_params);
   desc_params.add(hidden_options);