_dbus_header_byteswap: change the first byte of the message, not just the struct member

This has been wrong approximately forever, for instance see:
http://lists.freedesktop.org/archives/dbus/2007-March/007357.html

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=38120
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=629938
Reviewed-by: Will Thompson <will.thompson@collabora.co.uk>

1 files changed, 6 insertions, 0 deletions

diff --git a/dbus/dbus-marshal-header.c b/dbus/dbus-marshal-header.c
index 3f31d7a0..a6c9b80d 100644
--- a/dbus/dbus-marshal-header.c
+++ b/dbus/dbus-marshal-header.c
@@ -1468,14 +1468,20 @@ void
 _dbus_header_byteswap (DBusHeader *header,
                        int         new_order)
 {
+  unsigned char byte_order;
+
   if (header->byte_order == new_order)
     return;
 
+  byte_order = _dbus_string_get_byte (&header->data, BYTE_ORDER_OFFSET);
+  _dbus_assert (header->byte_order == byte_order);
+
   _dbus_marshal_byteswap (&_dbus_header_signature_str,
                           0, header->byte_order,
                           new_order,
                           &header->data, 0);
 
+  _dbus_string_set_byte (&header->data, BYTE_ORDER_OFFSET, new_order);
   header->byte_order = new_order;
 }