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.

2 files changed, 65 insertions, 3 deletions

diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index b524273bf..29597f5cc 100644
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -76,6 +76,11 @@ namespace cryptonote
     command_line::add_arg(desc, arg_rpc_bind_port);
     command_line::add_arg(desc, arg_rpc_restricted_bind_port);
     command_line::add_arg(desc, arg_restricted_rpc);
+    command_line::add_arg(desc, arg_rpc_ssl);
+    command_line::add_arg(desc, arg_rpc_ssl_private_key);
+    command_line::add_arg(desc, arg_rpc_ssl_certificate);
+    command_line::add_arg(desc, arg_rpc_ssl_allowed_certificates);
+    command_line::add_arg(desc, arg_rpc_ssl_allow_any_cert);
     command_line::add_arg(desc, arg_bootstrap_daemon_address);
     command_line::add_arg(desc, arg_bootstrap_daemon_login);
     cryptonote::rpc_args::init_options(desc);
@@ -112,11 +117,11 @@ namespace cryptonote
         epee::net_utils::http::login login;
         login.username = bootstrap_daemon_login.substr(0, loc);
         login.password = bootstrap_daemon_login.substr(loc + 1);
-        m_http_client.set_server(m_bootstrap_daemon_address, login, false);
+        m_http_client.set_server(m_bootstrap_daemon_address, login, epee::net_utils::ssl_support_t::e_ssl_support_autodetect);
       }
       else
       {
-        m_http_client.set_server(m_bootstrap_daemon_address, boost::none, false);
+        m_http_client.set_server(m_bootstrap_daemon_address, boost::none, epee::net_utils::ssl_support_t::e_ssl_support_autodetect);
       }
       m_should_use_bootstrap_daemon = true;
     }
@@ -131,9 +136,32 @@ namespace cryptonote
     if (rpc_config->login)
       http_login.emplace(std::move(rpc_config->login->username), std::move(rpc_config->login->password).password());
 
+    epee::net_utils::ssl_support_t ssl_support;
+    const std::string ssl = command_line::get_arg(vm, arg_rpc_ssl);
+    if (!epee::net_utils::ssl_support_from_string(ssl_support, ssl))
+    {
+      MFATAL("Invalid RPC SSL support: " << ssl);
+      return false;
+    }
+    const std::string ssl_private_key = command_line::get_arg(vm, arg_rpc_ssl_private_key);
+    const std::string ssl_certificate = command_line::get_arg(vm, arg_rpc_ssl_certificate);
+    const std::vector<std::string> ssl_allowed_certificate_paths = command_line::get_arg(vm, arg_rpc_ssl_allowed_certificates);
+    std::list<std::string> ssl_allowed_certificates;
+    for (const std::string &path: ssl_allowed_certificate_paths)
+    {
+      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();
+      }
+    }
+    const bool ssl_allow_any_cert = command_line::get_arg(vm, arg_rpc_ssl_allow_any_cert);
+
     auto rng = [](size_t len, uint8_t *ptr){ return crypto::rand(len, ptr); };
     return epee::http_server_impl_base<core_rpc_server, connection_context>::init(
-      rng, std::move(port), std::move(rpc_config->bind_ip), std::move(rpc_config->access_control_origins), std::move(http_login)
+      rng, std::move(port), std::move(rpc_config->bind_ip), std::move(rpc_config->access_control_origins), std::move(http_login),
+      ssl_support, std::make_pair(ssl_private_key, ssl_certificate), ssl_allowed_certificates, ssl_allow_any_cert
     );
   }
   //------------------------------------------------------------------------------------------------------------------------------
@@ -2317,6 +2345,35 @@ namespace cryptonote
     , false
     };
 
+  const command_line::arg_descriptor<std::string> core_rpc_server::arg_rpc_ssl = {
+      "rpc-ssl"
+    , "Enable SSL on RPC connections: enabled|disabled|autodetect"
+    , "autodetect"
+    };
+
+  const command_line::arg_descriptor<std::string> core_rpc_server::arg_rpc_ssl_private_key = {
+      "rpc-ssl-private-key"
+    , "Path to a PEM format private key"
+    , ""
+    };
+
+  const command_line::arg_descriptor<std::string> core_rpc_server::arg_rpc_ssl_certificate = {
+      "rpc-ssl-certificate"
+    , "Path to a PEM format certificate"
+    , ""
+    };
+
+  const command_line::arg_descriptor<std::vector<std::string>> core_rpc_server::arg_rpc_ssl_allowed_certificates = {
+      "rpc-ssl-allowed-certificates"
+    , "List of paths to PEM format certificates of allowed peers (all allowed if empty)"
+    };
+
+  const command_line::arg_descriptor<bool> core_rpc_server::arg_rpc_ssl_allow_any_cert = {
+      "rpc-ssl-allow-any-cert"
+    , "Allow any peer certificate, rather than just those on the allowed list"
+    , false
+    };
+
   const command_line::arg_descriptor<std::string> core_rpc_server::arg_bootstrap_daemon_address = {
       "bootstrap-daemon-address"
     , "URL of a 'bootstrap' remote daemon that the connected wallets can use while this daemon is still not fully synced"
diff --git a/src/rpc/core_rpc_server.h b/src/rpc/core_rpc_server.h
index 62a377841..da1907af2 100644
--- a/src/rpc/core_rpc_server.h
+++ b/src/rpc/core_rpc_server.h
@@ -56,6 +56,11 @@ namespace cryptonote
     static const command_line::arg_descriptor<std::string, false, true, 2> arg_rpc_bind_port;
     static const command_line::arg_descriptor<std::string> arg_rpc_restricted_bind_port;
     static const command_line::arg_descriptor<bool> arg_restricted_rpc;
+    static const command_line::arg_descriptor<std::string> arg_rpc_ssl;
+    static const command_line::arg_descriptor<std::string> arg_rpc_ssl_private_key;
+    static const command_line::arg_descriptor<std::string> arg_rpc_ssl_certificate;
+    static const command_line::arg_descriptor<std::vector<std::string>> arg_rpc_ssl_allowed_certificates;
+    static const command_line::arg_descriptor<bool> arg_rpc_ssl_allow_any_cert;
     static const command_line::arg_descriptor<std::string> arg_bootstrap_daemon_address;
     static const command_line::arg_descriptor<std::string> arg_bootstrap_daemon_login;