linux-kernel - Re: [PATCH v5 0/2] security: tty: make TIOCSTI ioctl require CAP_SYS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170425144746.0d8721a3@lxorguk.ukuu.org.uk>
Date:   Tue, 25 Apr 2017 14:47:46 +0100
From:   Alan Cox <gnomes@...rguk.ukuu.org.uk>
To:     Matt Brown <matt@...tt.com>
Cc:     serge@...lyn.com, jmorris@...ei.org, gregkh@...uxfoundation.org,
        jslaby@...e.com, corbet@....net, keescook@...omium.org,
        akpm@...ux-foundation.org, jannh@...gle.com,
        kernel-hardening@...ts.openwall.com,
        linux-security-module@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v5 0/2] security: tty: make TIOCSTI ioctl require
 CAP_SYS_ADMIN

> 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