1 files changed, 136 insertions, 0 deletions
diff --git a/src/network/credentials_manager.cpp b/src/network/credentials_manager.cpp
new file mode 100644
index 0000000..f93a366
--- /dev/null
+++ b/src/network/credentials_manager.cpp
@@ -0,0 +1,136 @@
+#include "biboumi.h"
+
+#ifdef BOTAN_FOUND
+#include <network/tcp_socket_handler.hpp>
+#include <network/credentials_manager.hpp>
+#include <logger/logger.hpp>
+#include <botan/tls_exceptn.h>
+#include <config/config.hpp>
+
+/**
+ * TODO find a standard way to find that out.
+ */
+static const std::vector<std::string> default_cert_files = {
+    "/etc/ssl/certs/ca-bundle.crt",
+    "/etc/pki/tls/certs/ca-bundle.crt",
+    "/etc/ssl/certs/ca-certificates.crt",
+    "/etc/ca-certificates/extracted/tls-ca-bundle.pem"
+};
+
+Botan::Certificate_Store_In_Memory BasicCredentialsManager::certificate_store;
+bool BasicCredentialsManager::certs_loaded = false;
+
+BasicCredentialsManager::BasicCredentialsManager(const TCPSocketHandler* const socket_handler):
+    Botan::Credentials_Manager(),
+    socket_handler(socket_handler),
+    trusted_fingerprint{}
+{
+  BasicCredentialsManager::load_certs();
+}
+
+void BasicCredentialsManager::set_trusted_fingerprint(const std::string& fingerprint)
+{
+  this->trusted_fingerprint = fingerprint;
+}
+
+const std::string& BasicCredentialsManager::get_trusted_fingerprint() const
+{
+  return this->trusted_fingerprint;
+}
+
+void check_tls_certificate(const std::vector<Botan::X509_Certificate>& certs,
+                           const std::string& hostname, const std::string& trusted_fingerprint,
+                           const std::exception_ptr& exc)
+{
+
+  if (!trusted_fingerprint.empty() && !certs.empty() &&
+      trusted_fingerprint == certs[0].fingerprint() &&
+      certs[0].matches_dns_name(hostname))
+    // We trust the certificate, based on the trusted fingerprint and
+    // the fact that the hostname matches
+    return;
+
+  if (exc)
+    std::rethrow_exception(exc);
+}
+
+#if BOTAN_VERSION_CODE < BOTAN_VERSION_CODE_FOR(1,11,34)
+void BasicCredentialsManager::verify_certificate_chain(const std::string& type,
+                                                       const std::string& purported_hostname,
+                                                       const std::vector<Botan::X509_Certificate>& certs)
+{
+  log_debug("Checking remote certificate (", type, ") for hostname ", purported_hostname);
+  try
+    {
+      Botan::Credentials_Manager::verify_certificate_chain(type, purported_hostname, certs);
+      log_debug("Certificate is valid");
+    }
+  catch (const std::exception& tls_exception)
+    {
+      log_warning("TLS certificate check failed: ", tls_exception.what());
+      std::exception_ptr exception_ptr{};
+      if (this->socket_handler->abort_on_invalid_cert())
+        exception_ptr = std::current_exception();
+
+      check_tls_certificate(certs, purported_hostname, this->trusted_fingerprint, exception_ptr);
+    }
+}
+#endif
+
+bool BasicCredentialsManager::try_to_open_one_ca_bundle(const std::vector<std::string>& paths)
+{
+  for (const auto& path: paths)
+    {
+      try
+        {
+          Botan::DataSource_Stream bundle(path);
+          log_debug("Using ca bundle: ", path);
+          while (!bundle.end_of_data() && bundle.check_available(27))
+            {
+              // TODO: remove this work-around for Botan 1.11.29
+              // https://github.com/randombit/botan/issues/438#issuecomment-192866796
+              // Note that every certificate that fails to be transcoded into latin-1
+              // will be ignored. As a result, some TLS connection may be refused
+              // because the certificate is signed by an issuer that was ignored.
+              try {
+                  Botan::X509_Certificate cert(bundle);
+                  BasicCredentialsManager::certificate_store.add_certificate(cert);
+                } catch (const Botan::Decoding_Error& error) {
+                  continue;
+                }
+            }
+          // Only use the first file that can successfully be read.
+          return true;
+        }
+      catch (const Botan::Stream_IO_Error& e)
+        {
+          log_debug(e.what());
+        }
+    }
+  return false;
+}
+
+void BasicCredentialsManager::load_certs()
+{
+  //  Only load the certificates the first time
+  if (BasicCredentialsManager::certs_loaded)
+    return;
+  const std::string conf_path = Config::get("ca_file", "");
+  std::vector<std::string> paths;
+  if (conf_path.empty())
+    paths = default_cert_files;
+  else
+    paths.push_back(conf_path);
+
+  if (BasicCredentialsManager::try_to_open_one_ca_bundle(paths))
+    BasicCredentialsManager::certs_loaded = true;
+  else
+    log_warning("The CA could not be loaded, TLS negociation will probably fail.");
+}
+
+std::vector<Botan::Certificate_Store*> BasicCredentialsManager::trusted_certificate_authorities(const std::string&, const std::string&)
+{
+  return {&this->certificate_store};
+}
+
+#endif