1. Introduction
1.1 Who needs that
2. Principles
2.1 Non reversible isolation
2.2 Isolation areas
2.3 New system calls
2.4 Limiting super-user: The capabilities system
2.5 Enhancing the capability system
2.6 Playing with the new system calls
2.6.1 Playing with /usr/sbin/chcontext
2.6.2 Playing with /usr/sbin/chcontext as root
2.6.3 Playing with /usr/sbin/chbind
2.6.4 Playing with /usr/sbin/reducecap
2.7 Unification
3. Applications
3.1 Virtual server
3.2 Per user fire-wall
3.3 Secure server/Intrusion detection
3.4 Fail over servers
4. Installation
4.1 The packages
4.2 Setting a virtual server
4.3 Basic configuration of the virtual server
4.4 Entering the virtual server
4.5 Configuring the services
4.6 Starting/Stopping the virtual server
4.7 Starting/Stopping all the virtual servers
4.8 Restarting a virtual server from inside
4.9 Executing tasks at vserver start/stop time
4.10 Issues
4.11 How real is it ?
5. Features
6. Future directions
6.1 User controlled security box
6.2 Kernel enhancements
6.2.1 Per context disk quota
6.2.2 Global limits
6.2.3 Scheduler
6.2.4 Security issues
6.2.4.1 /dev/random
6.2.4.2 /dev/pts
6.2.4.3 Network devices
7. Alternative technologies
7.1 Virtual machines
7.2 Partitioning
7.3 Limitation of those technologies
8. Conclusion
9. Download
10. References
Top Up

4.1 The packages

 Next

  • The kernel

    We are supplying a patched 2.4.26 kernel. You will find here the kernel, the .config and the patch.

    To install the kernel, just untar it. This will create a file /boot/kernel-2.4.26-vs1.28 (ctx stands for security context) and a directory /lib/modules/2.4.26-vs1.28.

    Then, you need to update your boot loader. For lilo, you add a section like this at the end of the file /etc/lilo.conf 


    
image=/boot/vmlinuz-2.4.26-vs1.28
	label=linux2.4.26-vs1.28
	read-only
	root=current

    lilo.conf section to add

    Change the /dev/XXXX to your root partition. Then execute /sbin/lilo.

    Reboot and select the proper kernel. This kernel is fully compatible with a normal 2.4.26 and will perform without any new configuration. Note that the supplied kernel does not carry all the features and modules found on the various distributions.

  • The vserver package

    This package provides the various utilities to make use of those new system calls. The package also provides a complete solution to implement virtual servers. We describe the major components here.

    • /usr/sbin/chcontext

      This is the utility to request a new security context. It can be used to lower the capability ceiling. Execute it to learn more.

    • /usr/sbin/chbind

      This is the utility to select one IP number and assign it to a process and its children.

    • /usr/sbin/newvserver (in vserver-admin)

      Front-end to help create new virtual servers.

    • /usr/sbin/reducecap

      This utility is used to lower the capability ceiling of children processes.

    • /usr/sbin/vdu

      A trimmed down "du" command reporting space usage of files with a single link. Useful to tell how much space a unified vserver is using.

    • /usr/sbin/vkill

      Locate the security context associated with a process, enter it and kill the process. Generally used after you have located a process with vtop, vpstree or vps.

    • /usr/sbin/vps

      Execute the ps command in security context 1 so all processes in all vservers are shown. The security context and vserver name are mapped inside the report.

    • /usr/sbin/vpstree

      Execute the pstree command in security context 1 so all processes in all vservers are shown.

    • /usr/sbin/vrpm

      Apply an rpm command in several (or all) vservers. Useful when you wish to update many vservers with the same package. 


      	/usr/sbin/vrpm server1 server2 -- -Uvh /tmp/*.rpm
	/usr/sbin/vrpm ALL -- -Uvh /tmp/*.rpm

      After updating many packages in different vservers you may want to re-unify them to recover disk space (and increase cache effectivity). You can do this using the vunify command, or simply by using the --unify option to the vrpm command. After performing the rpm updates, vrpm will trigger the vunify utility on the vservers for the updated packages. 


      	/usr/sbin/vrpm --unify server1 server2 -- -Uvh /tmp/*.rpm

    • /usr/sbin/vserver

      This is the wrapper to start, stop and administer virtual servers.

    • /usr/sbin/vserver-stat

      Produce a small report showing the activity in active security context. The report presents the number of process in each active security context as well as the name of the vserver associated with this context.

    • /usr/sbin/vtop

      Execute the top command in security context 1 so all processes in all vservers are shown.

    • /etc/rc.d/init.d/vservers

      This is an init script used to start all virtual servers at boot time and stop them at shutdown time. Only virtual servers with ONBOOT=yes are started at boot time. All vservers are stopped at shutdown time.

    • /etc/rc.d/init.d/rebootmgr

      This is a daemon listening to requests from virtual servers. It can either restart or stop a virtual server. The /sbin/vreboot and /sbin/vhalt utilities are used to send request to the reboot manager.

    • /sbin/vreboot and /sbin/vhalt

      Those utilities are copied in each virtual server. They connect to the reboot manager (rebootmgr) server using the /dev/reboot Unix domain socket and request either a restart or a stop of the virtual server. The reboot manager issue either a "/usr/sbin/vserver vserver restart" or "/usr/sbin/vserver vserver stop" command. This allows the virtual server administrator to test if all automatic service are properly restarted at boot time.

    • /usr/lib/vserver/vdu

      This is a limited clone of the du command. It skips file with more than one link. It is used to evaluate the disk usage of an unified vserver. Using the normal du for this task is misleading since it will count all unified files.

Top Up

Next
One big HTML document