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.

1 files changed, 31 insertions, 1 deletions

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);