Re: [PATCH v5 0/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN

[Alan Cox]

> There could be a few user programs that would be effected by this
> change.
> See: <https://codesearch.debian.net/search?q=ioctl%5C%28.*TIOCSTI>
> notable programs are: agetty, csh, xemacs and tcsh
> 
> However, I still believe that this change is worth it given that the
> Kconfig defaults to n. This will be a feature that is turned on for the
> same reason that people activate it when using grsecurity. Users of this
> opt-in feature will realize that they are choosing security over some OS
> features 

Only in this case they are not.

If I am at the point I have the ability to send you TIOCSTI you already
lost because I can just open /dev/tty to get access to my controlling tty
and use write().

Alan