[Spice-devel] [spice-gtk 2/2] Recheck clipboard size after modifying its data

[Marc-André Lureau]

looks good, ack

On Mon, Nov 17, 2014 at 3:17 PM, Christophe Fergeau <cfergeau at redhat.com> wrote:
> SpiceGtkSession::clipboard_received_cb() starts by checking if the
> clipboard is empty, or if the length of its data exceeds
> 'max-clipboard-size'.
>
> Later in that function, the data is modified, and can be shortened
> (removal of trailing '\0' or of '\r' for Windows -> linux copy and
> paste), or enlarged (addition of '\r' for linux -> Windows c&p).
>
> This commit adds another check that the clipboard length is still valid
> (non-0, and not bigger than 'max-clipboard-size') after making these
> transformations.
> ---
>  gtk/spice-gtk-session.c | 29 ++++++++++++++++++++++-------
>  1 file changed, 22 insertions(+), 7 deletions(-)
>
> diff --git a/gtk/spice-gtk-session.c b/gtk/spice-gtk-session.c
> index 26a0ecf..ca32d28 100644
> --- a/gtk/spice-gtk-session.c
> +++ b/gtk/spice-gtk-session.c
> @@ -826,6 +826,24 @@ skip_grab_clipboard:
>      return TRUE;
>  }
>
> +static gboolean check_clipboard_size_limits(SpiceGtkSession *session,
> +                                            gint clipboard_len)
> +{
> +    int max_clipboard;
> +
> +    g_object_get(session->priv->main, "max-clipboard", &max_clipboard, NULL);
> +    if (max_clipboard != -1 && clipboard_len > max_clipboard) {
> +        g_warning("discarded clipboard of size %d (max: %d)",
> +                  clipboard_len, max_clipboard);
> +        return FALSE;
> +    } else if (clipboard_len <= 0) {
> +        SPICE_DEBUG("discarding empty clipboard");
> +        return FALSE;
> +    }
> +
> +    return TRUE;
> +}
> +
>  static void clipboard_received_cb(GtkClipboard *clipboard,
>                                    GtkSelectionData *selection_data,
>                                    gpointer user_data)
> @@ -845,18 +863,12 @@ static void clipboard_received_cb(GtkClipboard *clipboard,
>      gchar* name;
>      GdkAtom atom;
>      int selection;
> -    int max_clipboard;
>
>      selection = get_selection_from_clipboard(s, clipboard);
>      g_return_if_fail(selection != -1);
>
> -    g_object_get(s->main, "max-clipboard", &max_clipboard, NULL);
>      len = gtk_selection_data_get_length(selection_data);
> -    if (max_clipboard != -1 && len > max_clipboard) {
> -        g_warning("discarded clipboard of size %d (max: %d)", len, max_clipboard);
> -        return;
> -    } else if (len <= 0) {
> -        SPICE_DEBUG("discarding empty clipboard");
> +    if (!check_clipboard_size_limits(self, len)) {
>          return;
>      } else {
>          atom = gtk_selection_data_get_data_type(selection_data);
> @@ -902,6 +914,9 @@ static void clipboard_received_cb(GtkClipboard *clipboard,
>               */
>              len = strlen((const char *)data);
>          }
> +        if (!check_clipboard_size_limits(self, len)) {
> +            return;
> +        }
>      }
>
>      spice_main_clipboard_selection_notify(s->main, selection, type,
> --
> 2.1.0
>
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-- 
Marc-André Lureau