Re: [kernel-hardening] Re: [PATCH v6 0/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN

[Daniel Micay]

On Wed, 2017-05-10 at 21:29 +0100, Alan Cox wrote:
> 
> In addition your change to allow it to be used by root in the guest
> completely invalidates any protection you have because I can push
> 
> "rm -rf /\n"
> 
> as root in my namespace and exit
> 
> The tty buffers are not flushed across the context change so the shell
> you return to gets the input and oh dear....
> 
> Alan

I might be missing something, but it looks like the patch tracks where
the tty was created and only allows this with CAP_SYS_ADMIN in the ns
where the tty came from.