Support a trusted SHA1 fingerprint to be configured for each IRC server

database/database.xml

@@ -13,6 +13,7 @@
         <field name="username" type="string" length="1024" default=""/>
         <field name="realname" type="string" length="1024" default=""/>
         <field name="verifyCert" type="boolean" default="true"/>
+        <field name="trustedFingerprint" type="string"/>
 
         <field name="encodingOut" type="string" default="ISO-8859-1"/>
         <field name="encodingIn"  type="string" default="ISO-8859-1"/>

louloulibs/network/credentials_manager.cpp

@@ -26,11 +26,17 @@ bool Basic_Credentials_Manager::certs_loaded = false;
 
 Basic_Credentials_Manager::Basic_Credentials_Manager(const TCPSocketHandler* const socket_handler):
     Botan::Credentials_Manager(),
-    socket_handler(socket_handler)
+    socket_handler(socket_handler),
+    trusted_fingerprint{}
 {
   this->load_certs();
 }
 
+void Basic_Credentials_Manager::set_trusted_fingerprint(const std::string& fingerprint)
+{
+  this->trusted_fingerprint = fingerprint;
+}
+
 void Basic_Credentials_Manager::verify_certificate_chain(const std::string& type,
                                                          const std::string& purported_hostname,
                                                          const std::vector<Botan::X509_Certificate>& certs)
@@ -44,6 +50,13 @@ void Basic_Credentials_Manager::verify_certificate_chain(const std::string& type
   catch (const std::exception& tls_exception)
     {
       log_warning("TLS certificate check failed: " << tls_exception.what());
+      if (!this->trusted_fingerprint.empty() && !certs.empty() &&
+          this->trusted_fingerprint == certs[0].fingerprint() &&
+          certs[0].matches_dns_name(purported_hostname))
+        // We trust the certificate, based on the trusted fingerprint and
+        // the fact that the hostname matches
+        return;
+
       if (this->socket_handler->abort_on_invalid_cert())
         throw;
     }

louloulibs/network/credentials_manager.hpp

@@ -19,6 +19,7 @@ public:
                                 const std::vector<Botan::X509_Certificate>&) override final;
   std::vector<Botan::Certificate_Store*> trusted_certificate_authorities(const std::string& type,
                                                                          const std::string& context) override final;
+  void set_trusted_fingerprint(const std::string& fingerprint);
 
 private:
   const TCPSocketHandler* const socket_handler;
@@ -26,6 +27,7 @@ private:
   static void load_certs();
   static Botan::Certificate_Store_In_Memory certificate_store;
   static bool certs_loaded;
+  std::string trusted_fingerprint;
 };
 
 #endif //BOTAN_FOUND

louloulibs/network/tcp_socket_handler.hpp

@@ -248,7 +248,9 @@ private:
   static Botan::AutoSeeded_RNG rng;
   static Botan::TLS::Policy policy;
   static Botan::TLS::Session_Manager_In_Memory session_manager;
+protected:
   Basic_Credentials_Manager credential_manager;
+private:
   /**
    * We use a unique_ptr because we may not want to create the object at
    * all. The Botan::TLS::Client object generates a handshake message and

src/irc/irc_client.cpp

@@ -89,6 +89,13 @@ void IrcClient::start()
 
   this->bind_addr = Config::get("outgoing_bind", "");
 
+#ifdef BOTAN_FOUND
+# ifdef USE_DATABASE
+  auto options = Database::get_irc_server_options(this->bridge.get_bare_jid(),
+                                                  this->get_hostname());
+  this->credential_manager.set_trusted_fingerprint(options.trustedFingerprint);
+# endif
+#endif
   this->connect(this->hostname, port, tls);
 }
 

src/xmpp/biboumi_adhoc_commands.cpp

@@ -175,6 +175,19 @@ void ConfigureIrcServerStep1(XmppComponent&, AdhocSession& session, XmlNode& com
     verify_cert_value.set_inner("false");
   verify_cert.add_child(std::move(verify_cert_value));
   x.add_child(std::move(verify_cert));
+
+  XmlNode fingerprint("field");
+  fingerprint["var"] = "fingerprint";
+  fingerprint["type"] = "text-single";
+  fingerprint["label"] = "SHA-1 fingerprint of the TLS certificate to trust.";
+  if (!options.trustedFingerprint.value().empty())
+    {
+      XmlNode fingerprint_value("value");
+      fingerprint_value.set_inner(options.trustedFingerprint.value());
+      fingerprint.add_child(std::move(fingerprint_value));
+    }
+  fingerprint.add_child(required);
+  x.add_child(std::move(fingerprint));
 #endif
 
   XmlNode pass("field");
@@ -301,6 +314,13 @@ void ConfigureIrcServerStep2(XmppComponent&, AdhocSession& session, XmlNode& com
               auto val = to_bool(value->get_inner());
               options.verifyCert = val;
             }
+
+          else if (field->get_tag("var") == "fingerprint" && value &&
+                   !value->get_inner().empty())
+            {
+              options.trustedFingerprint = value->get_inner();
+            }
+
 #endif // BOTAN_FOUND
 
           else if (field->get_tag("var") == "pass" &&