SysRq (Magic SysRq key)

[Patrick]

Quote Screen Locker (In)Security - Can we disable these at least 4 backdoors?

@Patrick

A lot ways to disable the screensaver.

We might have to reconsider SysRq (Magic SysRq key) as per:

Backdoor #3: Alt-SysRq-F .

This is the Linux kernel “OOM-killer” keystroke. It shoots down random long-running programs of its choosing, and so might might target and kill xscreensaver, and there’s no way for xscreensaver to protect itself from that. You can disable it globally with: sudo ‘echo 176 > /proc/sys/kernel/sysrq’

What does 176 value for /proc/sys/kernel/sysrq mean? Anyone can find documentation for that?