path: root/0001-vnc-Add-anonymous-TLS-encryption-support.patch

From 546151b4e15fd45901f38172435cd9aa63893727 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Thu, 14 Jun 2018 12:21:37 +0200
Subject: [PATCH 1/6] vnc: Add anonymous TLS encryption support

Add support for encrypting the VNC connection using anonymous TLS. In
effect this means that the channel is encrypted using TLS but that no
authentication of the peers are done. This means the connection is still
vulnerable to man-in-the-middle attacks where an attacker proxies the
VNC connection.
---
 meson.build                                   |   1 +
 src/grd-enums.h                               |   6 +
 src/grd-session-vnc.c                         |  98 +++-
 src/grd-session-vnc.h                         |  15 +
 src/grd-settings.c                            |  28 ++
 src/grd-settings.h                            |   2 +
 src/grd-vnc-server.c                          |  45 ++
 src/grd-vnc-tls.c                             | 444 ++++++++++++++++++
 src/grd-vnc-tls.h                             |  28 ++
 src/meson.build                               |   5 +-
 ...nome.desktop.remote-desktop.gschema.xml.in |  10 +
 11 files changed, 666 insertions(+), 16 deletions(-)
 create mode 100644 src/grd-vnc-tls.c
 create mode 100644 src/grd-vnc-tls.h

diff --git a/meson.build b/meson.build
index af423a4..813c97f 100644
--- a/meson.build
+++ b/meson.build
@@ -20,6 +20,7 @@ libvncclient_dep = dependency('libvncclient')
 libsecret_dep = dependency('libsecret-1')
 libnotify_dep = dependency('libnotify')
 winpr_dep = dependency('winpr2', version: freerdp_req)
+gnutls_dep = dependency('gnutls')
 
 cdata = configuration_data()
 cdata.set_quoted('GETTEXT_PACKAGE', 'gnome-remote-desktop')
diff --git a/src/grd-enums.h b/src/grd-enums.h
index ffab821..4333863 100644
--- a/src/grd-enums.h
+++ b/src/grd-enums.h
@@ -27,4 +27,10 @@ typedef enum
   GRD_VNC_AUTH_METHOD_PASSWORD
 } GrdVncAuthMethod;
 
+typedef enum
+{
+  GRD_VNC_ENCRYPTION_NONE = 1 << 0,
+  GRD_VNC_ENCRYPTION_TLS_ANON = 1 << 1,
+} GrdVncEncryption;
+
 #endif /* GRD_ENUMS_H */
diff --git a/src/grd-session-vnc.c b/src/grd-session-vnc.c
index a06d34d..d014315 100644
--- a/src/grd-session-vnc.c
+++ b/src/grd-session-vnc.c
@@ -44,7 +44,9 @@ struct _GrdSessionVnc
 {
   GrdSession parent;
 
+  GrdVncServer *vnc_server;
   GSocketConnection *connection;
+  GList *socket_grabs;
   GSource *source;
   rfbScreenInfoPtr rfb_screen;
   rfbClientPtr rfb_client;
@@ -518,12 +520,30 @@ check_rfb_password (rfbClientPtr  rfb_client,
     }
 }
 
+int
+grd_session_vnc_get_fd (GrdSessionVnc *session_vnc)
+{
+  return session_vnc->rfb_screen->inetdSock;
+}
+
 int
 grd_session_vnc_get_framebuffer_stride (GrdSessionVnc *session_vnc)
 {
   return session_vnc->rfb_screen->paddedWidthInBytes;
 }
 
+rfbClientPtr
+grd_session_vnc_get_rfb_client (GrdSessionVnc *session_vnc)
+{
+  return session_vnc->rfb_client;
+}
+
+GrdVncServer *
+grd_session_vnc_get_vnc_server (GrdSessionVnc *session_vnc)
+{
+  return session_vnc->vnc_server;
+}
+
 static void
 init_vnc_session (GrdSessionVnc *session_vnc)
 {
@@ -564,33 +584,74 @@ init_vnc_session (GrdSessionVnc *session_vnc)
   rfbProcessEvents (rfb_screen, 0);
 }
 
+void
+grd_session_vnc_grab_socket (GrdSessionVnc        *session_vnc,
+                             GrdVncSocketGrabFunc  grab_func)
+{
+  session_vnc->socket_grabs = g_list_prepend (session_vnc->socket_grabs,
+                                              grab_func);
+}
+
+void
+grd_session_vnc_ungrab_socket (GrdSessionVnc        *session_vnc,
+                               GrdVncSocketGrabFunc  grab_func)
+{
+  session_vnc->socket_grabs = g_list_remove (session_vnc->socket_grabs,
+                                             grab_func);
+}
+
+static gboolean
+vnc_socket_grab_func (GrdSessionVnc  *session_vnc,
+                      GError        **error)
+{
+  if (rfbIsActive (session_vnc->rfb_screen))
+    {
+      rfbProcessEvents (session_vnc->rfb_screen, 0);
+
+      if (session_vnc->pending_framebuffer_resize &&
+          session_vnc->rfb_client->preferredEncoding != -1)
+        {
+          resize_vnc_framebuffer (session_vnc,
+                                  session_vnc->pending_framebuffer_width,
+                                  session_vnc->pending_framebuffer_height);
+          session_vnc->pending_framebuffer_resize = FALSE;
+        }
+    }
+
+  return TRUE;
+}
+
 static gboolean
 handle_socket_data (GSocket *socket,
                     GIOCondition condition,
                     gpointer user_data)
 {
-  GrdSessionVnc *session_vnc = user_data;
+  GrdSessionVnc *session_vnc = GRD_SESSION_VNC (user_data);
+  GrdSession *session = GRD_SESSION (session_vnc);
 
-  if (condition & G_IO_IN)
+  if (condition & (G_IO_ERR | G_IO_HUP))
+    {
+      g_warning ("Client disconnected");
+
+      grd_session_stop (session);
+    }
+  else if (condition & G_IO_IN)
     {
-      if (rfbIsActive (session_vnc->rfb_screen))
+      GrdVncSocketGrabFunc grab_func;
+      g_autoptr (GError) error = NULL;
+
+      grab_func = g_list_first (session_vnc->socket_grabs)->data;
+      if (!grab_func (session_vnc, &error))
         {
-          rfbProcessEvents (session_vnc->rfb_screen, 0);
+          g_warning ("Error when reading socket: %s", error->message);
 
-          if (session_vnc->pending_framebuffer_resize &&
-              session_vnc->rfb_client->preferredEncoding != -1)
-            {
-              resize_vnc_framebuffer (session_vnc,
-                                      session_vnc->pending_framebuffer_width,
-                                      session_vnc->pending_framebuffer_height);
-              session_vnc->pending_framebuffer_resize = FALSE;
-            }
+          grd_session_stop (session);
         }
     }
   else
     {
-      g_debug ("Unhandled socket condition %d\n", condition);
-      return G_SOURCE_REMOVE;
+      g_warning ("Unhandled socket condition %d\n", condition);
+      g_assert_not_reached ();
     }
 
   return G_SOURCE_CONTINUE;
@@ -603,7 +664,10 @@ grd_session_vnc_attach_source (GrdSessionVnc *session_vnc)
 
   socket = g_socket_connection_get_socket (session_vnc->connection);
   session_vnc->source = g_socket_create_source (socket,
-                                                G_IO_IN | G_IO_PRI,
+                                                (G_IO_IN |
+                                                 G_IO_PRI |
+                                                 G_IO_ERR |
+                                                 G_IO_HUP),
                                                 NULL);
   g_source_set_callback (session_vnc->source,
                          (GSourceFunc) handle_socket_data,
@@ -629,8 +693,10 @@ grd_session_vnc_new (GrdVncServer      *vnc_server,
                               "context", context,
                               NULL);
 
+  session_vnc->vnc_server = vnc_server;
   session_vnc->connection = g_object_ref (connection);
 
+  grd_session_vnc_grab_socket (session_vnc, vnc_socket_grab_func);
   grd_session_vnc_attach_source (session_vnc);
 
   init_vnc_session (session_vnc);
@@ -645,6 +711,8 @@ grd_session_vnc_dispose (GObject *object)
 
   g_assert (!session_vnc->rfb_screen);
 
+  g_clear_pointer (&session_vnc->socket_grabs, g_list_free);
+
   g_clear_pointer (&session_vnc->pressed_keys, g_hash_table_unref);
 
   G_OBJECT_CLASS (grd_session_vnc_parent_class)->dispose (object);
diff --git a/src/grd-session-vnc.h b/src/grd-session-vnc.h
index 07678c8..bba3d56 100644
--- a/src/grd-session-vnc.h
+++ b/src/grd-session-vnc.h
@@ -36,6 +36,9 @@ G_DECLARE_FINAL_TYPE (GrdSessionVnc,
                       GRD, SESSION_VNC,
                       GrdSession);
 
+typedef gboolean (* GrdVncSocketGrabFunc) (GrdSessionVnc  *session_vnc,
+                                           GError        **error);
+
 GrdSessionVnc *grd_session_vnc_new (GrdVncServer      *vnc_server,
                                     GSocketConnection *connection);
 
@@ -55,8 +58,20 @@ void grd_session_vnc_move_cursor (GrdSessionVnc *session_vnc,
                                   int            x,
                                   int            y);
 
+int grd_session_vnc_get_fd (GrdSessionVnc *session_vnc);
+
 int grd_session_vnc_get_framebuffer_stride (GrdSessionVnc *session_vnc);
 
 gboolean grd_session_vnc_is_client_gone (GrdSessionVnc *session_vnc);
 
+rfbClientPtr grd_session_vnc_get_rfb_client (GrdSessionVnc *session_vnc);
+
+void grd_session_vnc_grab_socket (GrdSessionVnc        *session_vnc,
+                                  GrdVncSocketGrabFunc  grab_func);
+
+void grd_session_vnc_ungrab_socket (GrdSessionVnc        *session_vnc,
+                                    GrdVncSocketGrabFunc  grab_func);
+
+GrdVncServer * grd_session_vnc_get_vnc_server (GrdSessionVnc *session_vnc);
+
 #endif /* GRD_SESSION_VNC_H */
diff --git a/src/grd-settings.c b/src/grd-settings.c
index 3af87be..f37f2da 100644
--- a/src/grd-settings.c
+++ b/src/grd-settings.c
@@ -60,6 +60,7 @@ struct _GrdSettings
     gboolean view_only;
     GrdVncAuthMethod auth_method;
     int port;
+    GrdVncEncryption encryption;
   } vnc;
 };
 
@@ -232,6 +233,12 @@ grd_settings_get_vnc_auth_method (GrdSettings *settings)
     return settings->vnc.auth_method;
 }
 
+GrdVncEncryption
+grd_settings_get_vnc_encryption (GrdSettings *settings)
+{
+  return settings->vnc.encryption;
+}
+
 static void
 update_rdp_tls_cert (GrdSettings *settings)
 {
@@ -267,6 +274,13 @@ update_vnc_auth_method (GrdSettings *settings)
                                                    "auth-method");
 }
 
+static void
+update_vnc_encryption (GrdSettings *settings)
+{
+  settings->vnc.encryption = g_settings_get_flags (settings->vnc.settings,
+                                                   "encryption");
+}
+
 static void
 on_rdp_settings_changed (GSettings   *rdp_settings,
                          const char  *key,
@@ -304,6 +318,11 @@ on_vnc_settings_changed (GSettings   *vnc_settings,
       update_vnc_auth_method (settings);
       g_signal_emit (settings, signals[VNC_AUTH_METHOD_CHANGED], 0);
     }
+  else if (strcmp (key, "encryption") == 0)
+    {
+      update_vnc_encryption (settings);
+      g_signal_emit (settings, signals[VNC_ENCRYPTION_CHANGED], 0);
+    }
 }
 
 static void
@@ -335,6 +354,8 @@ grd_settings_init (GrdSettings *settings)
 
   settings->rdp.port = GRD_RDP_SERVER_PORT;
   settings->vnc.port = GRD_VNC_SERVER_PORT;
+
+  update_vnc_encryption (settings);
 }
 
 static void
@@ -379,4 +400,11 @@ grd_settings_class_init (GrdSettingsClass *klass)
                   0,
                   NULL, NULL, NULL,
                   G_TYPE_NONE, 0);
+  signals[VNC_ENCRYPTION_CHANGED] =
+    g_signal_new ("vnc-encryption-changed",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_NONE, 0);
 }
diff --git a/src/grd-settings.h b/src/grd-settings.h
index e12e47e..b940fdb 100644
--- a/src/grd-settings.h
+++ b/src/grd-settings.h
@@ -64,4 +64,6 @@ gboolean grd_settings_get_vnc_view_only (GrdSettings *settings);
 
 GrdVncAuthMethod grd_settings_get_vnc_auth_method (GrdSettings *settings);
 
+GrdVncEncryption grd_settings_get_vnc_encryption (GrdSettings *settings);
+
 #endif /* GRD_SETTINGS_H */
diff --git a/src/grd-vnc-server.c b/src/grd-vnc-server.c
index a6d95cb..f9c68db 100644
--- a/src/grd-vnc-server.c
+++ b/src/grd-vnc-server.c
@@ -24,11 +24,13 @@
 
 #include "grd-vnc-server.h"
 
+#include <rfb/rfb.h>
 #include <gio/gio.h>
 #include <rfb/rfb.h>
 
 #include "grd-context.h"
 #include "grd-session-vnc.h"
+#include "grd-vnc-tls.h"
 
 
 enum
@@ -130,6 +132,43 @@ on_incoming (GSocketService    *service,
   return TRUE;
 }
 
+static void
+sync_encryption_settings (GrdVncServer *vnc_server)
+{
+  GrdSettings *settings = grd_context_get_settings (vnc_server->context);
+  rfbSecurityHandler *tls_security_handler;
+  GrdVncEncryption encryption;
+
+  tls_security_handler = grd_vnc_tls_get_security_handler ();
+  encryption = grd_settings_get_vnc_encryption (settings);
+
+  if (encryption == (GRD_VNC_ENCRYPTION_NONE | GRD_VNC_ENCRYPTION_TLS_ANON))
+    {
+      rfbRegisterSecurityHandler (tls_security_handler);
+      rfbUnregisterChannelSecurityHandler (tls_security_handler);
+    }
+  else if (encryption == GRD_VNC_ENCRYPTION_NONE)
+    {
+      rfbUnregisterSecurityHandler (tls_security_handler);
+      rfbUnregisterChannelSecurityHandler (tls_security_handler);
+    }
+  else
+    {
+      if (encryption != GRD_VNC_ENCRYPTION_TLS_ANON)
+        g_warning ("Invalid VNC encryption setting, falling back to TLS-ANON");
+
+      rfbRegisterChannelSecurityHandler (tls_security_handler);
+      rfbUnregisterSecurityHandler (tls_security_handler);
+    }
+}
+
+static void
+on_vnc_encryption_changed (GrdSettings  *settings,
+                           GrdVncServer *vnc_server)
+{
+  sync_encryption_settings (vnc_server);
+}
+
 gboolean
 grd_vnc_server_start (GrdVncServer  *vnc_server,
                       GError       **error)
@@ -220,12 +259,18 @@ static void
 grd_vnc_server_constructed (GObject *object)
 {
   GrdVncServer *vnc_server = GRD_VNC_SERVER (object);
+  GrdSettings *settings = grd_context_get_settings (vnc_server->context);
 
   if (grd_context_get_debug_flags (vnc_server->context) & GRD_DEBUG_VNC)
     rfbLogEnable (1);
   else
     rfbLogEnable (0);
 
+  g_signal_connect (settings, "vnc-encryption-changed",
+                    G_CALLBACK (on_vnc_encryption_changed),
+                    vnc_server);
+  sync_encryption_settings (vnc_server);
+
   G_OBJECT_CLASS (grd_vnc_server_parent_class)->constructed (object);
 }
 
diff --git a/src/grd-vnc-tls.c b/src/grd-vnc-tls.c
new file mode 100644
index 0000000..ec4758e
--- /dev/null
+++ b/src/grd-vnc-tls.c
@@ -0,0 +1,444 @@
+/*
+ * Copyright (C) 2018 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#include "grd-vnc-tls.h"
+
+#include <errno.h>
+#include <glib.h>
+#include <gnutls/gnutls.h>
+#include <rfb/rfb.h>
+
+#include "grd-session-vnc.h"
+#include "grd-vnc-server.h"
+
+typedef struct _GrdVncTlsContext
+{
+  gnutls_anon_server_credentials_t anon_credentials;
+  gnutls_dh_params_t dh_params;
+} GrdVncTlsContext;
+
+typedef enum _GrdTlsHandshakeState
+{
+  GRD_TLS_HANDSHAKE_STATE_INIT,
+  GRD_TLS_HANDSHAKE_STATE_DURING,
+  GRD_TLS_HANDSHAKE_STATE_FINISHED
+} GrdTlsHandshakeState;
+
+typedef struct _GrdVncTlsSession
+{
+  GrdVncTlsContext *tls_context;
+
+  int fd;
+
+  gnutls_session_t tls_session;
+  GrdTlsHandshakeState handshake_state;
+
+  char *peek_buffer;
+  int peek_buffer_size;
+  int peek_buffer_len;
+} GrdVncTlsSession;
+
+static gboolean
+tls_handshake_grab_func (GrdSessionVnc  *session_vnc,
+                         GError        **error);
+
+static GrdVncTlsContext *
+grd_vnc_tls_context_new (void)
+{
+  GrdVncTlsContext *tls_context;
+  const unsigned int dh_bits = 1024;
+
+  tls_context = g_new0 (GrdVncTlsContext, 1);
+
+  gnutls_global_init ();
+
+  gnutls_anon_allocate_server_credentials (&tls_context->anon_credentials);
+
+  gnutls_dh_params_init (&tls_context->dh_params);
+  gnutls_dh_params_generate2 (tls_context->dh_params, dh_bits);
+
+  gnutls_anon_set_server_dh_params (tls_context->anon_credentials,
+                                    tls_context->dh_params);
+
+  return tls_context;
+}
+
+static void
+grd_vnc_tls_context_free (GrdVncTlsContext *tls_context)
+{
+  gnutls_dh_params_deinit (tls_context->dh_params);
+  gnutls_anon_free_server_credentials (tls_context->anon_credentials);
+  gnutls_global_deinit ();
+}
+
+GrdVncTlsContext *
+ensure_tls_context (GrdVncServer *vnc_server)
+{
+  GrdVncTlsContext *tls_context;
+
+  tls_context = g_object_get_data (G_OBJECT (vnc_server), "vnc-tls-context");
+  if (!tls_context)
+    {
+      tls_context = grd_vnc_tls_context_new ();
+      g_object_set_data_full (G_OBJECT (vnc_server), "vnc-tls-context",
+                              tls_context,
+                              (GDestroyNotify) grd_vnc_tls_context_free);
+    }
+
+  return tls_context;
+}
+
+static gboolean
+perform_anon_tls_handshake (GrdVncTlsSession  *tls_session,
+                            GError           **error)
+{
+  GrdVncTlsContext *tls_context = tls_session->tls_context;
+  const char kx_priority[] = "NORMAL:+ANON-DH";
+  int ret;
+
+  gnutls_init (&tls_session->tls_session, GNUTLS_SERVER | GNUTLS_NO_SIGNAL);
+
+  gnutls_set_default_priority (tls_session->tls_session);
+  gnutls_priority_set_direct (tls_session->tls_session, kx_priority, NULL);
+
+  gnutls_credentials_set (tls_session->tls_session,
+                          GNUTLS_CRD_ANON,
+                          tls_context->anon_credentials);
+  gnutls_transport_set_ptr (tls_session->tls_session,
+                            GINT_TO_POINTER (tls_session->fd));
+
+  ret = gnutls_handshake (tls_session->tls_session);
+  if (ret != GNUTLS_E_SUCCESS && !gnutls_error_is_fatal (ret))
+    {
+      tls_session->handshake_state = GRD_TLS_HANDSHAKE_STATE_DURING;
+      return TRUE;
+    }
+
+  if (ret != GNUTLS_E_SUCCESS)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "%s", gnutls_strerror (ret));
+      gnutls_deinit (tls_session->tls_session);
+      tls_session->tls_session = NULL;
+      return FALSE;
+    }
+
+  tls_session->handshake_state = GRD_TLS_HANDSHAKE_STATE_FINISHED;
+  return TRUE;
+}
+
+static gboolean
+continue_tls_handshake (GrdVncTlsSession  *tls_session,
+                        GError           **error)
+{
+  int ret;
+
+  ret = gnutls_handshake (tls_session->tls_session);
+  if (ret != GNUTLS_E_SUCCESS && !gnutls_error_is_fatal (ret))
+    return TRUE;
+
+  if (ret != GNUTLS_E_SUCCESS)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "%s", gnutls_strerror (ret));
+      gnutls_deinit (tls_session->tls_session);
+      tls_session->tls_session = NULL;
+      return FALSE;
+    }
+
+  tls_session->handshake_state = GRD_TLS_HANDSHAKE_STATE_FINISHED;
+  return TRUE;
+}
+
+static void
+grd_vnc_tls_session_free (GrdVncTlsSession *tls_session)
+{
+  g_clear_pointer (&tls_session->peek_buffer, g_free);
+  g_clear_pointer (&tls_session->tls_session, gnutls_deinit);
+  g_free (tls_session);
+}
+
+static GrdVncTlsSession *
+grd_vnc_tls_session_from_vnc_session (GrdSessionVnc *session_vnc)
+{
+  return g_object_get_data (G_OBJECT (session_vnc), "vnc-tls-session");
+}
+
+static int
+do_read (GrdVncTlsSession *tls_session,
+         char             *buf,
+         int               len)
+{
+  do
+    {
+      int ret;
+
+      ret = gnutls_record_recv (tls_session->tls_session, buf, len);
+      if (ret == GNUTLS_E_AGAIN ||
+          ret == GNUTLS_E_INTERRUPTED)
+        {
+          continue;
+        }
+      else if (ret < 0)
+        {
+          g_debug ("gnutls_record_recv failed: %s", gnutls_strerror (ret));
+          errno = EIO;
+          return -1;
+        }
+      else
+        {
+          return ret;
+        }
+    }
+  while (TRUE);
+}
+
+static int
+grd_vnc_tls_read_from_socket (rfbClientPtr  rfb_client,
+                              char         *buf,
+                              int           len)
+{
+  GrdSessionVnc *session_vnc = rfb_client->screen->screenData;
+  GrdVncTlsSession *tls_session =
+    grd_vnc_tls_session_from_vnc_session (session_vnc);
+  int to_read = len;
+  int len_read = 0;
+
+  if (to_read < tls_session->peek_buffer_len)
+    {
+      memcpy (buf, tls_session->peek_buffer, to_read);
+      memmove (buf,
+               tls_session->peek_buffer + to_read,
+               tls_session->peek_buffer_len - to_read);
+      len_read = to_read;
+      to_read = 0;
+    }
+  else
+    {
+      memcpy (buf,
+              tls_session->peek_buffer,
+              tls_session->peek_buffer_len);
+      to_read -= tls_session->peek_buffer_len;
+      len_read = tls_session->peek_buffer_len;
+
+      g_clear_pointer (&tls_session->peek_buffer,
+                       g_free);
+      tls_session->peek_buffer_len = 0;
+      tls_session->peek_buffer_size = 0;
+    }
+
+  if (to_read > 0)
+    {
+      int ret;
+
+      ret = do_read (tls_session, buf + len_read, to_read);
+      if (ret == -1)
+        return -1;
+
+      len_read += ret;
+    }
+
+  return len_read;
+}
+
+static int
+grd_vnc_tls_peek_at_socket (rfbClientPtr  rfb_client,
+                            char         *buf,
+                            int           len)
+{
+  GrdSessionVnc *session_vnc = rfb_client->screen->screenData;
+  GrdVncTlsSession *tls_session =
+    grd_vnc_tls_session_from_vnc_session (session_vnc);
+  int peekable_len;
+
+  if (tls_session->peek_buffer_len < len)
+    {
+      int ret;
+
+      if (len > tls_session->peek_buffer_size)
+        {
+          tls_session->peek_buffer = g_renew (char,
+                                              tls_session->peek_buffer,
+                                              len);
+          tls_session->peek_buffer_size = len;
+        }
+
+      ret = do_read (tls_session,
+                     tls_session->peek_buffer + tls_session->peek_buffer_len,
+                     len - tls_session->peek_buffer_len);
+      if (ret == -1)
+        return -1;
+
+      tls_session->peek_buffer_len += ret;
+    }
+
+  peekable_len = MIN (len, tls_session->peek_buffer_len);
+  memcpy (buf, tls_session->peek_buffer, peekable_len);
+
+  return peekable_len;
+}
+
+static rfbBool
+grd_vnc_tls_has_pending_on_socket (rfbClientPtr rfb_client)
+{
+  GrdSessionVnc *session_vnc = rfb_client->screen->screenData;
+  GrdVncTlsSession *tls_session =
+    grd_vnc_tls_session_from_vnc_session (session_vnc);
+
+  if (tls_session->peek_buffer_len > 0)
+    return TRUE;
+
+  if (gnutls_record_check_pending (tls_session->tls_session) > 0)
+    return TRUE;
+
+  return FALSE;
+}
+
+static int
+grd_vnc_tls_write_to_socket (rfbClientPtr  rfb_client,
+                             const char   *buf,
+                             int           len)
+{
+  GrdSessionVnc *session_vnc = rfb_client->screen->screenData;
+  GrdVncTlsSession *tls_session =
+    grd_vnc_tls_session_from_vnc_session (session_vnc);
+
+  do
+    {
+      int ret;
+
+      ret = gnutls_record_send (tls_session->tls_session, buf, len);
+      if (ret == GNUTLS_E_AGAIN ||
+          ret == GNUTLS_E_INTERRUPTED)
+        {
+          continue;
+        }
+      else if (ret < 0)
+        {
+          g_debug ("gnutls_record_send failed: %s", gnutls_strerror (ret));
+          errno = EIO;
+          return -1;
+        }
+      else
+        {
+          return ret;
+        }
+    }
+  while (TRUE);
+}
+
+static gboolean
+perform_handshake (GrdSessionVnc  *session_vnc,
+                   GError        **error)
+{
+  GrdVncTlsSession *tls_session =
+    grd_vnc_tls_session_from_vnc_session (session_vnc);
+
+  switch (tls_session->handshake_state)
+    {
+    case GRD_TLS_HANDSHAKE_STATE_INIT:
+      if (!perform_anon_tls_handshake (tls_session, error))
+        return FALSE;
+      break;
+    case GRD_TLS_HANDSHAKE_STATE_DURING:
+      if (!continue_tls_handshake (tls_session, error))
+        return FALSE;
+      break;
+    case GRD_TLS_HANDSHAKE_STATE_FINISHED:
+      break;
+    }
+
+  switch (tls_session->handshake_state)
+    {
+    case GRD_TLS_HANDSHAKE_STATE_INIT:
+      break;
+    case GRD_TLS_HANDSHAKE_STATE_DURING:
+      break;
+    case GRD_TLS_HANDSHAKE_STATE_FINISHED:
+      grd_session_vnc_ungrab_socket (session_vnc, tls_handshake_grab_func);
+      rfbSendSecurityTypeList (grd_session_vnc_get_rfb_client (session_vnc),
+                               RFB_SECURITY_TAG_CHANNEL);
+      break;
+    }
+
+  return TRUE;
+}
+
+static gboolean
+tls_handshake_grab_func (GrdSessionVnc  *session_vnc,
+                         GError        **error)
+{
+  g_autoptr (GError) handshake_error = NULL;
+
+  if (!perform_handshake (session_vnc, &handshake_error))
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "TLS handshake failed: %s", handshake_error->message);
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+static void
+rfb_tls_security_handler (rfbClientPtr rfb_client)
+{
+  GrdSessionVnc *session_vnc = rfb_client->screen->screenData;
+  GrdVncTlsSession *tls_session;
+  g_autoptr(GError) error = NULL;
+
+  tls_session = grd_vnc_tls_session_from_vnc_session (session_vnc);
+  if (!tls_session)
+    {
+      GrdVncServer *vnc_server = grd_session_vnc_get_vnc_server (session_vnc);
+
+      tls_session = g_new0 (GrdVncTlsSession, 1);
+      tls_session->fd = grd_session_vnc_get_fd (session_vnc);
+      tls_session->tls_context = ensure_tls_context (vnc_server);
+      g_object_set_data_full (G_OBJECT (session_vnc), "vnc-tls-session",
+                              tls_session,
+                              (GDestroyNotify) grd_vnc_tls_session_free);
+
+      rfb_client->readFromSocket = grd_vnc_tls_read_from_socket;
+      rfb_client->peekAtSocket = grd_vnc_tls_peek_at_socket;
+      rfb_client->hasPendingOnSocket = grd_vnc_tls_has_pending_on_socket;
+      rfb_client->writeToSocket = grd_vnc_tls_write_to_socket;
+
+      grd_session_vnc_grab_socket (session_vnc, tls_handshake_grab_func);
+    }
+
+  if (!perform_handshake (session_vnc, &error))
+    {
+      g_warning ("TLS handshake failed: %s", error->message);
+      rfbCloseClient (rfb_client);
+    }
+}
+
+static rfbSecurityHandler anon_tls_security_handler = {
+  .type = rfbTLS,
+  .handler = rfb_tls_security_handler,
+  .securityTags = RFB_SECURITY_TAG_CHANNEL,
+};
+
+rfbSecurityHandler *
+grd_vnc_tls_get_security_handler (void)
+{
+  return &anon_tls_security_handler;
+}
diff --git a/src/grd-vnc-tls.h b/src/grd-vnc-tls.h
new file mode 100644
index 0000000..135ef8c
--- /dev/null
+++ b/src/grd-vnc-tls.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2018 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#ifndef GRD_VNC_TLS_H
+#define GRD_VNC_TLS_H
+
+#include <rfb/rfb.h>
+
+rfbSecurityHandler * grd_vnc_tls_get_security_handler (void);
+
+#endif /* GRD_VNC_TLS_H */
diff --git a/src/meson.build b/src/meson.build
index 1b6425d..17579b1 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -33,6 +33,8 @@ daemon_sources = files([
   'grd-vnc-pipewire-stream.h',
   'grd-vnc-server.c',
   'grd-vnc-server.h',
+  'grd-vnc-tls.c',
+  'grd-vnc-tls.h',
 ])
 
 gen_daemon_sources = []
@@ -66,7 +68,8 @@ executable('gnome-remote-desktop-daemon',
                           libvncserver_dep,
                           libsecret_dep,
                           libnotify_dep,
-                          winpr_dep],
+                          winpr_dep,
+                          gnutls_dep],
            include_directories: [configinc],
            install: true,
            install_dir: libexecdir)
diff --git a/src/org.gnome.desktop.remote-desktop.gschema.xml.in b/src/org.gnome.desktop.remote-desktop.gschema.xml.in
index 4b6e593..0086d99 100644
--- a/src/org.gnome.desktop.remote-desktop.gschema.xml.in
+++ b/src/org.gnome.desktop.remote-desktop.gschema.xml.in
@@ -49,5 +49,15 @@
 	 * password - by requiring the remote client to provide a known password
       </description>
     </key>
+    <key name='encryption' flags='org.gnome.desktop.remote-desktop.GrdVncEncryption'>
+      <default>['tls-anon']</default>
+      <summary>Allowed encryption method to use</summary>
+      <description>
+	Allowed encryption methods. Includes the following:
+
+	 * none     - no encryption
+	 * tls-anon - anonymous (unauthenticated) TLS
+      </description>
+    </key>
   </schema>
 </schemalist>
-- 
2.26.2


From 2e46518f421fd8704770bb6742accfacba3570aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Wed, 27 Nov 2019 11:02:09 +0100
Subject: [PATCH 2/6] session-vnc: Add paused/resumed signals

Paused is when the socket sourec is detached, and resumed when attached.
Meant to be used by the TLS channel security to a attach/detach
out-of-socket source.
---
 src/grd-session-vnc.c | 72 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 65 insertions(+), 7 deletions(-)

diff --git a/src/grd-session-vnc.c b/src/grd-session-vnc.c
index d014315..7edd407 100644
--- a/src/grd-session-vnc.c
+++ b/src/grd-session-vnc.c
@@ -40,14 +40,27 @@
 #define BGRX_SAMPLES_PER_PIXEL 3
 #define BGRX_BYTES_PER_PIXEL 4
 
+enum
+{
+  PAUSED,
+  RESUMED,
+
+  N_SIGNALS
+};
+
+static guint signals[N_SIGNALS];
+
 struct _GrdSessionVnc
 {
   GrdSession parent;
 
   GrdVncServer *vnc_server;
   GSocketConnection *connection;
+
   GList *socket_grabs;
   GSource *source;
+  gboolean is_paused;
+
   rfbScreenInfoPtr rfb_screen;
   rfbClientPtr rfb_client;
 
@@ -73,7 +86,7 @@ struct _GrdSessionVnc
 G_DEFINE_TYPE (GrdSessionVnc, grd_session_vnc, GRD_TYPE_SESSION);
 
 static void
-grd_session_vnc_detach_source (GrdSessionVnc *session_vnc);
+grd_session_vnc_pause (GrdSessionVnc *session_vnc);
 
 static gboolean
 close_session_idle (gpointer user_data);
@@ -224,7 +237,8 @@ handle_client_gone (rfbClientPtr rfb_client)
 
   g_debug ("VNC client gone");
 
-  grd_session_vnc_detach_source (session_vnc);
+  grd_session_vnc_pause (session_vnc);
+
   maybe_queue_close_session_idle (session_vnc);
   session_vnc->rfb_client = NULL;
 }
@@ -293,7 +307,7 @@ handle_new_client (rfbClientPtr rfb_client)
                               session_vnc->prompt_cancellable,
                               prompt_response_callback,
                               session_vnc);
-      grd_session_vnc_detach_source (session_vnc);
+      grd_session_vnc_pause (session_vnc);
       return RFB_CLIENT_ON_HOLD;
     case GRD_VNC_AUTH_METHOD_PASSWORD:
       session_vnc->rfb_screen->passwordCheck = check_rfb_password;
@@ -511,7 +525,7 @@ check_rfb_password (rfbClientPtr  rfb_client,
   if (memcmp (challenge_encrypted, response_encrypted, len) == 0)
     {
       grd_session_start (GRD_SESSION (session_vnc));
-      grd_session_vnc_detach_source (session_vnc);
+      grd_session_vnc_pause (session_vnc);
       return TRUE;
     }
   else
@@ -681,6 +695,36 @@ grd_session_vnc_detach_source (GrdSessionVnc *session_vnc)
   g_clear_pointer (&session_vnc->source, g_source_destroy);
 }
 
+gboolean
+grd_session_vnc_is_paused (GrdSessionVnc *session_vnc)
+{
+  return session_vnc->is_paused;
+}
+
+static void
+grd_session_vnc_pause (GrdSessionVnc *session_vnc)
+{
+  if (grd_session_vnc_is_paused (session_vnc))
+    return;
+
+  session_vnc->is_paused = TRUE;
+
+  grd_session_vnc_detach_source (session_vnc);
+  g_signal_emit (session_vnc, signals[PAUSED], 0);
+}
+
+static void
+grd_session_vnc_resume (GrdSessionVnc *session_vnc)
+{
+  if (!grd_session_vnc_is_paused (session_vnc))
+    return;
+
+  session_vnc->is_paused = FALSE;
+
+  grd_session_vnc_attach_source (session_vnc);
+  g_signal_emit (session_vnc, signals[RESUMED], 0);
+}
+
 GrdSessionVnc *
 grd_session_vnc_new (GrdVncServer      *vnc_server,
                      GSocketConnection *connection)
@@ -698,6 +742,7 @@ grd_session_vnc_new (GrdVncServer      *vnc_server,
 
   grd_session_vnc_grab_socket (session_vnc, vnc_socket_grab_func);
   grd_session_vnc_attach_source (session_vnc);
+  session_vnc->is_paused = FALSE;
 
   init_vnc_session (session_vnc);
 
@@ -727,7 +772,7 @@ grd_session_vnc_stop (GrdSession *session)
 
   g_clear_object (&session_vnc->pipewire_stream);
 
-  grd_session_vnc_detach_source (session_vnc);
+  grd_session_vnc_pause (session_vnc);
 
   g_clear_object (&session_vnc->connection);
   g_clear_pointer (&session_vnc->rfb_screen->frameBuffer, g_free);
@@ -783,8 +828,8 @@ grd_session_vnc_stream_ready (GrdSession *session,
                     G_CALLBACK (on_pipewire_stream_closed),
                     session_vnc);
 
-  if (!session_vnc->source)
-    grd_session_vnc_attach_source (session_vnc);
+  if (grd_session_vnc_is_paused (session_vnc))
+    grd_session_vnc_resume (session_vnc);
 }
 
 static void
@@ -803,4 +848,17 @@ grd_session_vnc_class_init (GrdSessionVncClass *klass)
 
   session_class->stop = grd_session_vnc_stop;
   session_class->stream_ready = grd_session_vnc_stream_ready;
+
+  signals[PAUSED] = g_signal_new ("paused",
+                                  G_TYPE_FROM_CLASS (klass),
+                                  G_SIGNAL_RUN_LAST,
+                                  0,
+                                  NULL, NULL, NULL,
+                                  G_TYPE_NONE, 0);
+  signals[RESUMED] = g_signal_new ("resumed",
+                                   G_TYPE_FROM_CLASS (klass),
+                                   G_SIGNAL_RUN_LAST,
+                                   0,
+                                   NULL, NULL, NULL,
+                                   G_TYPE_NONE, 0);
 }
-- 
2.26.2


From b59c36ccf73939d32ccf5ab4eb47460a9fe415f3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Wed, 27 Nov 2019 11:03:46 +0100
Subject: [PATCH 3/6] session-vnc: Add grd_session_vnc_dispatch() helper

To be used by the TLS channel security to dispatch when there is data
available that is not visible to the socket source.
---
 src/grd-session-vnc.c | 26 ++++++++++++++++----------
 src/grd-session-vnc.h |  2 ++
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/grd-session-vnc.c b/src/grd-session-vnc.c
index 7edd407..29c94a1 100644
--- a/src/grd-session-vnc.c
+++ b/src/grd-session-vnc.c
@@ -635,6 +635,21 @@ vnc_socket_grab_func (GrdSessionVnc  *session_vnc,
   return TRUE;
 }
 
+void
+grd_session_vnc_dispatch (GrdSessionVnc *session_vnc)
+{
+  GrdVncSocketGrabFunc grab_func;
+  g_autoptr (GError) error = NULL;
+
+  grab_func = g_list_first (session_vnc->socket_grabs)->data;
+  if (!grab_func (session_vnc, &error))
+    {
+      g_warning ("Error when reading socket: %s", error->message);
+
+      grd_session_stop (GRD_SESSION (session_vnc));
+    }
+}
+
 static gboolean
 handle_socket_data (GSocket *socket,
                     GIOCondition condition,
@@ -651,16 +666,7 @@ handle_socket_data (GSocket *socket,
     }
   else if (condition & G_IO_IN)
     {
-      GrdVncSocketGrabFunc grab_func;
-      g_autoptr (GError) error = NULL;
-
-      grab_func = g_list_first (session_vnc->socket_grabs)->data;
-      if (!grab_func (session_vnc, &error))
-        {
-          g_warning ("Error when reading socket: %s", error->message);
-
-          grd_session_stop (session);
-        }
+      grd_session_vnc_dispatch (session_vnc);
     }
   else
     {
diff --git a/src/grd-session-vnc.h b/src/grd-session-vnc.h
index bba3d56..58f635c 100644
--- a/src/grd-session-vnc.h
+++ b/src/grd-session-vnc.h
@@ -72,6 +72,8 @@ void grd_session_vnc_grab_socket (GrdSessionVnc        *session_vnc,
 void grd_session_vnc_ungrab_socket (GrdSessionVnc        *session_vnc,
                                     GrdVncSocketGrabFunc  grab_func);
 
+void grd_session_vnc_dispatch (GrdSessionVnc *session_vnc);
+
 GrdVncServer * grd_session_vnc_get_vnc_server (GrdSessionVnc *session_vnc);
 
 #endif /* GRD_SESSION_VNC_H */
-- 
2.26.2


From 966b2ddbd1c03c9e20dc66e5ea9a2dfb39ba4bfa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Wed, 27 Nov 2019 11:05:13 +0100
Subject: [PATCH 4/6] vnc/tls: Add some logging

Uses the log utility from libvncserver as it is related to the RFB
protocol rather than the session itself.
---
 src/grd-vnc-tls.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/grd-vnc-tls.c b/src/grd-vnc-tls.c
index ec4758e..ac6c35f 100644
--- a/src/grd-vnc-tls.c
+++ b/src/grd-vnc-tls.c
@@ -67,6 +67,7 @@ grd_vnc_tls_context_new (void)
 
   tls_context = g_new0 (GrdVncTlsContext, 1);
 
+  rfbLog ("TLS: Initializing gnutls context\n");
   gnutls_global_init ();
 
   gnutls_anon_allocate_server_credentials (&tls_context->anon_credentials);
@@ -127,6 +128,7 @@ perform_anon_tls_handshake (GrdVncTlsSession  *tls_session,
   ret = gnutls_handshake (tls_session->tls_session);
   if (ret != GNUTLS_E_SUCCESS && !gnutls_error_is_fatal (ret))
     {
+      rfbLog ("TLS: More handshake pending\n");
       tls_session->handshake_state = GRD_TLS_HANDSHAKE_STATE_DURING;
       return TRUE;
     }
@@ -140,6 +142,8 @@ perform_anon_tls_handshake (GrdVncTlsSession  *tls_session,
       return FALSE;
     }
 
+  rfbLog ("TLS: Handshake finished");
+
   tls_session->handshake_state = GRD_TLS_HANDSHAKE_STATE_FINISHED;
   return TRUE;
 }
@@ -373,6 +377,7 @@ perform_handshake (GrdSessionVnc  *session_vnc,
       break;
     case GRD_TLS_HANDSHAKE_STATE_FINISHED:
       grd_session_vnc_ungrab_socket (session_vnc, tls_handshake_grab_func);
+      rfbLog ("TLS: Sending post-channel security security list\n");
       rfbSendSecurityTypeList (grd_session_vnc_get_rfb_client (session_vnc),
                                RFB_SECURITY_TAG_CHANNEL);
       break;
@@ -387,6 +392,7 @@ tls_handshake_grab_func (GrdSessionVnc  *session_vnc,
 {
   g_autoptr (GError) handshake_error = NULL;
 
+  rfbLog ("TLS: Continuing handshake\n");
   if (!perform_handshake (session_vnc, &handshake_error))
     {
       g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
@@ -404,6 +410,8 @@ rfb_tls_security_handler (rfbClientPtr rfb_client)
   GrdVncTlsSession *tls_session;
   g_autoptr(GError) error = NULL;
 
+  rfbLog ("TLS: Setting up rfbClient for gnutls encrypted traffic\n");
+
   tls_session = grd_vnc_tls_session_from_vnc_session (session_vnc);
   if (!tls_session)
     {
@@ -424,6 +432,7 @@ rfb_tls_security_handler (rfbClientPtr rfb_client)
       grd_session_vnc_grab_socket (session_vnc, tls_handshake_grab_func);
     }
 
+  rfbLog ("TLS: Performing handshake\n");
   if (!perform_handshake (session_vnc, &error))
     {
       g_warning ("TLS handshake failed: %s", error->message);
-- 
2.26.2


From e01d27dc9911f4d7ecfd232c7e389f4dabfd87de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Wed, 27 Nov 2019 11:07:40 +0100
Subject: [PATCH 5/6] vnc/tls: Dispatch also when data is pending outside of
 the socket

gnutls may have data available in its buffers, and we have our own peek
buffer temporarly storing data later to be processed. This would missed
by the socket source, as it wouldn't get any notification about it from
epoll(). Deal with this by adding a custom source that dispatches as
long as there is data to read in those buffers.
---
 src/grd-session-vnc.h |  2 +
 src/grd-vnc-tls.c     | 90 ++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 86 insertions(+), 6 deletions(-)

diff --git a/src/grd-session-vnc.h b/src/grd-session-vnc.h
index 58f635c..0d01ad3 100644
--- a/src/grd-session-vnc.h
+++ b/src/grd-session-vnc.h
@@ -72,6 +72,8 @@ void grd_session_vnc_grab_socket (GrdSessionVnc        *session_vnc,
 void grd_session_vnc_ungrab_socket (GrdSessionVnc        *session_vnc,
                                     GrdVncSocketGrabFunc  grab_func);
 
+gboolean grd_session_vnc_is_paused (GrdSessionVnc *session_vnc);
+
 void grd_session_vnc_dispatch (GrdSessionVnc *session_vnc);
 
 GrdVncServer * grd_session_vnc_get_vnc_server (GrdSessionVnc *session_vnc);
diff --git a/src/grd-vnc-tls.c b/src/grd-vnc-tls.c
index ac6c35f..312b6b9 100644
--- a/src/grd-vnc-tls.c
+++ b/src/grd-vnc-tls.c
@@ -41,6 +41,12 @@ typedef enum _GrdTlsHandshakeState
   GRD_TLS_HANDSHAKE_STATE_FINISHED
 } GrdTlsHandshakeState;
 
+typedef struct _PeekBufferSource
+{
+  GSource parent;
+  GrdSessionVnc *session_vnc;
+} PeekBufferSource;
+
 typedef struct _GrdVncTlsSession
 {
   GrdVncTlsContext *tls_context;
@@ -53,6 +59,8 @@ typedef struct _GrdVncTlsSession
   char *peek_buffer;
   int peek_buffer_size;
   int peek_buffer_len;
+
+  GSource *peek_buffer_source;
 } GrdVncTlsSession;
 
 static gboolean
@@ -299,13 +307,9 @@ grd_vnc_tls_peek_at_socket (rfbClientPtr  rfb_client,
   return peekable_len;
 }
 
-static rfbBool
-grd_vnc_tls_has_pending_on_socket (rfbClientPtr rfb_client)
+static gboolean
+grd_vnc_tls_session_has_pending_data (GrdVncTlsSession *tls_session)
 {
-  GrdSessionVnc *session_vnc = rfb_client->screen->screenData;
-  GrdVncTlsSession *tls_session =
-    grd_vnc_tls_session_from_vnc_session (session_vnc);
-
   if (tls_session->peek_buffer_len > 0)
     return TRUE;
 
@@ -315,6 +319,16 @@ grd_vnc_tls_has_pending_on_socket (rfbClientPtr rfb_client)
   return FALSE;
 }
 
+static rfbBool
+grd_vnc_tls_has_pending_on_socket (rfbClientPtr rfb_client)
+{
+  GrdSessionVnc *session_vnc = rfb_client->screen->screenData;
+  GrdVncTlsSession *tls_session =
+    grd_vnc_tls_session_from_vnc_session (session_vnc);
+
+  return grd_vnc_tls_session_has_pending_data (tls_session);
+}
+
 static int
 grd_vnc_tls_write_to_socket (rfbClientPtr  rfb_client,
                              const char   *buf,
@@ -403,6 +417,62 @@ tls_handshake_grab_func (GrdSessionVnc  *session_vnc,
   return TRUE;
 }
 
+static gboolean
+peek_buffer_source_prepare (GSource *source,
+                            int     *timeout)
+{
+  PeekBufferSource *psource = (PeekBufferSource *) source;
+  GrdSessionVnc *session_vnc = psource->session_vnc;
+  GrdVncTlsSession *tls_session =
+    grd_vnc_tls_session_from_vnc_session (session_vnc);
+
+  return grd_vnc_tls_session_has_pending_data (tls_session);
+}
+
+static gboolean
+peek_buffer_source_dispatch (GSource     *source,
+                             GSourceFunc  callback,
+                             gpointer     user_data)
+{
+  PeekBufferSource *psource = (PeekBufferSource *) source;
+  GrdSessionVnc *session_vnc = psource->session_vnc;
+
+  grd_session_vnc_dispatch (session_vnc);
+
+  return G_SOURCE_CONTINUE;
+}
+
+static GSourceFuncs peek_buffer_source_funcs = {
+  .prepare = peek_buffer_source_prepare,
+  .dispatch = peek_buffer_source_dispatch,
+};
+
+static void
+attach_peek_buffer_source (GrdSessionVnc *session_vnc)
+{
+  GrdVncTlsSession *tls_session;
+
+  tls_session = grd_vnc_tls_session_from_vnc_session (session_vnc);
+  tls_session->peek_buffer_source = g_source_new (&peek_buffer_source_funcs,
+                                                  sizeof (PeekBufferSource));
+  ((PeekBufferSource *) tls_session->peek_buffer_source)->session_vnc =
+    session_vnc;
+  g_source_set_priority (tls_session->peek_buffer_source,
+                         G_PRIORITY_DEFAULT + 1);
+
+  g_source_attach (tls_session->peek_buffer_source, NULL);
+}
+
+static void
+detach_peek_buffer_source (GrdSessionVnc *session_vnc)
+{
+  GrdVncTlsSession *tls_session;
+
+  tls_session = grd_vnc_tls_session_from_vnc_session (session_vnc);
+
+  g_clear_pointer (&tls_session->peek_buffer_source, g_source_destroy);
+}
+
 static void
 rfb_tls_security_handler (rfbClientPtr rfb_client)
 {
@@ -429,6 +499,14 @@ rfb_tls_security_handler (rfbClientPtr rfb_client)
       rfb_client->hasPendingOnSocket = grd_vnc_tls_has_pending_on_socket;
       rfb_client->writeToSocket = grd_vnc_tls_write_to_socket;
 
+      if (!grd_session_vnc_is_paused (session_vnc))
+        attach_peek_buffer_source (session_vnc);
+
+      g_signal_connect (session_vnc, "paused",
+                        G_CALLBACK (detach_peek_buffer_source), NULL);
+      g_signal_connect (session_vnc, "resumed",
+                        G_CALLBACK (attach_peek_buffer_source), NULL);
+
       grd_session_vnc_grab_socket (session_vnc, tls_handshake_grab_func);
     }
 
-- 
2.26.2


From 682f3b4a8e985f00a00e761a086a15cb5e2b9b04 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Wed, 27 Nov 2019 16:48:00 +0100
Subject: [PATCH 6/6] session-vnc: Set our own password handling function up
 front

libvncserver decides whether to register a auth security handler
depending on whether the password data is set or not. When we use the
prompt auth method, we don't want to ask for password, so set the
password data to NULL.

Also, to be a bit more in control of the password mechanism, always set
the password function up front, instead of just when the client uses the
password prompt.
---
 src/grd-session-vnc.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/src/grd-session-vnc.c b/src/grd-session-vnc.c
index 29c94a1..ebe1540 100644
--- a/src/grd-session-vnc.c
+++ b/src/grd-session-vnc.c
@@ -91,11 +91,6 @@ grd_session_vnc_pause (GrdSessionVnc *session_vnc);
 static gboolean
 close_session_idle (gpointer user_data);
 
-static rfbBool
-check_rfb_password (rfbClientPtr  rfb_client,
-                    const char   *response_encrypted,
-                    int           len);
-
 static void
 swap_uint8 (uint8_t *a,
             uint8_t *b)
@@ -310,7 +305,6 @@ handle_new_client (rfbClientPtr rfb_client)
       grd_session_vnc_pause (session_vnc);
       return RFB_CLIENT_ON_HOLD;
     case GRD_VNC_AUTH_METHOD_PASSWORD:
-      session_vnc->rfb_screen->passwordCheck = check_rfb_password;
       /*
        * authPasswdData needs to be non NULL in libvncserver to trigger
        * password authentication.
@@ -594,6 +588,8 @@ init_vnc_session (GrdSessionVnc *session_vnc)
   rfb_screen->frameBuffer = g_malloc0 (screen_width * screen_height * 4);
   memset (rfb_screen->frameBuffer, 0x1f, screen_width * screen_height * 4);
 
+  rfb_screen->passwordCheck = check_rfb_password;
+
   rfbInitServer (rfb_screen);
   rfbProcessEvents (rfb_screen, 0);
 }
-- 
2.26.2