Change SSL certificate file list to OpenSSL builtin load_verify_location

Specifying SSL certificates for peer verification does an exact match,
making it a not-so-obvious alias for the fingerprints option. This
changes the checks to OpenSSL which loads concatenated certificate(s)
from a single file and does a certificate-authority (chain of trust)
check instead. There is no drop in security - a compromised exact match
fingerprint has the same worse case failure. There is increased security
in allowing separate long-term CA key and short-term SSL server keys.

This also removes loading of the system-default CA files if a custom
CA file or certificate fingerprint is specified.

1 files changed, 5 insertions, 15 deletions

diff --git a/src/wallet/wallet_rpc_server.cpp b/src/wallet/wallet_rpc_server.cpp
index 92265d954..7824ed62e 100644
--- a/src/wallet/wallet_rpc_server.cpp
+++ b/src/wallet/wallet_rpc_server.cpp
@@ -68,7 +68,7 @@ namespace
   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)")};
+  const command_line::arg_descriptor<std::string> arg_rpc_ssl_ca_certificates = {"rpc-ssl-ca-certificates", tools::wallet2::tr("Path to file containing concatenated PEM format certificate(s) to replace system CA(s).")};
   const command_line::arg_descriptor<std::vector<std::string>> arg_rpc_ssl_allowed_fingerprints = {"rpc-ssl-allowed-fingerprints", tools::wallet2::tr("List of certificate fingerprints to allow")};
 
   constexpr const char default_rpc_username[] = "monero";
@@ -247,7 +247,7 @@ namespace tools
 
     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_ca_file = command_line::get_arg(vm, arg_rpc_ssl_ca_certificates);
     auto rpc_ssl_allowed_fingerprints = command_line::get_arg(vm, arg_rpc_ssl_allowed_fingerprints);
     auto rpc_ssl = command_line::get_arg(vm, arg_rpc_ssl);
     epee::net_utils::ssl_support_t rpc_ssl_support;
@@ -256,16 +256,6 @@ namespace tools
       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();
-        }
-    }
 
     std::vector<std::vector<uint8_t>> allowed_fingerprints{ rpc_ssl_allowed_fingerprints.size() };
     std::transform(rpc_ssl_allowed_fingerprints.begin(), rpc_ssl_allowed_fingerprints.end(), allowed_fingerprints.begin(), epee::from_hex::vector);
@@ -277,7 +267,7 @@ namespace tools
     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),
-      rpc_ssl_support, std::make_pair(rpc_ssl_private_key, rpc_ssl_certificate), std::move(allowed_certificates), std::move(allowed_fingerprints)
+      rpc_ssl_support, std::make_pair(rpc_ssl_private_key, rpc_ssl_certificate), std::move(rpc_ssl_ca_file), std::move(allowed_fingerprints)
     );
   }
   //------------------------------------------------------------------------------------------------------------------------------
@@ -4070,7 +4060,7 @@ namespace tools
       for (auto c: fp)
         v.push_back(c);
     }
-    if (!m_wallet->set_daemon(req.address, boost::none, req.trusted, ssl_support, std::make_pair(req.ssl_private_key_path, req.ssl_certificate_path), req.ssl_allowed_certificates, ssl_allowed_fingerprints, req.ssl_allow_any_cert))
+    if (!m_wallet->set_daemon(req.address, boost::none, req.trusted, ssl_support, std::make_pair(req.ssl_private_key_path, req.ssl_certificate_path), std::move(req.ssl_ca_file), ssl_allowed_fingerprints, req.ssl_allow_any_cert))
     {
       er.code = WALLET_RPC_ERROR_CODE_NO_DAEMON_CONNECTION;
       er.message = std::string("Unable to set daemon");
@@ -4278,7 +4268,7 @@ int main(int argc, char** argv) {
   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);
+  command_line::add_arg(desc_params, arg_rpc_ssl_ca_certificates);
   command_line::add_arg(desc_params, arg_rpc_ssl_allowed_fingerprints);
 
   daemonizer::init_options(hidden_options, desc_params);