In Linux and Oracle Solaris guests,
After installing the Guest Additions into a fresh installation
of a supported Linux distribution or Oracle Solaris system,
many unsupported systems will work correctly too, the guest's
graphics mode will change to fit the size of the
Multiple guest monitors are supported in guests using the X.Org server version 1.3, which is part of release 7.3 of the X Window System version 11, or a later version. The layout of the guest screens can be adjusted as needed using the tools which come with the guest operating system.
If you want to understand more about the details of how the X.Org drivers are set up, in
particular if you want to use them in a setting which our installer does not handle correctly,
see
Starting from
VBoxDRMClient runs as a root process and is a bridge between the host and the guest's vmwgfx driver. This means that VBoxDRMClient listens to screen resize hints from the host and forwards them to the vmwgfx driver. This enables guest screen resize functionality to be available before the user has performed a graphical login.
In order to perform Desktop Environment specific actions, such as setting the primary screen in a multimonitor setup, a Desktop Environment helper is used. Once the user has performed a graphical login operation, the helper daemon starts with user session scope and attempts to connect to VBoxDRMClient using an IPC connection. When VBoxDRMClient has received a corresponding command from the host, it is forwarded to the helper daemon over IPC and the action is then performed.
By default, VBoxDRMClient allows any process to connect to its IPC socket. This can be restricted by using the following steps:
The Guest Additions Linux installer creates a
You must set the
VBoxManage guestproperty set "VM name" /VirtualBox/GuestAdd/DRMIpcRestricted 1 \ --flags RDONLYGUEST
It is important to set only the RDONLYGUEST flag for the property, so that it cannot be changed from inside the guest.
Both steps are required. If one of them is missing, all processes will have access to the IPC socket.
Restricted mode can be disabled by unsetting the guest property, as follows:
VBoxManage guestproperty unset "VM name" /VirtualBox/GuestAdd/DRMIpcRestricted