Vlock
vlock is a Virtual Console lock program.
Concepts
Sometimes a malicious local user could cause more problems than a sophisticated remote one. vlock is a program that locks one or more sessions on the Linux console to prevent attackers from gaining physical access to the machine.
Installation
USE flags
USE flags for app-misc/vlock A console screen locker
Emerge
To install app-misc/vlock:
root #
emerge --ask app-misc/vlock
Usage
When not working in a virtual console, switch to one by pressing CTRL+ALT+F1 through F6. By default, vlock locks the current console session. Use the -a
switch in order to lock all console sessions.
user $
vlock -a
It is also possible to use vlock from an X session. Use the -n
option to make vlock switch to an empty virtual console.
root #
usermod -a -G vlock larry
user $
vlock -na
Disable SysRq key
The magic SysRq key combination can unlock consoles when least expected. In order to prevent this, disable the SysRq mechanism while consoles are locked like so:
user $
vlock -sa
If a user does not know how to use the SysRq key, then it is probably not needed. Disable it when configuring the kernel:
Kernel hacking ---> [ ] Magic SysRq key