Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN

From	Matt Brown <matt@nmatt.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN
Date	2017-04-20 02:10 +0200
Message-ID	<ty7Pz-1FO-7@gated-at.bofh.it> (permalink)
References	<txOMV-6En-9@gated-at.bofh.it> <txVOq-2NI-17@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 04/19/2017 07:18 AM, James Morris wrote:
> On Tue, 18 Apr 2017, Matt Brown wrote:
>
>> This patch reproduces GRKERNSEC_HARDEN_TTY functionality from the grsecurity
>> project in-kernel.
>
> It seems like an ugly hack to an ugly feature (CAP_SYS_ADMIN barely makes
> sense here), and rather than sprinkling these types of things throughout
> the kernel, I wonder if it might be better to implement it via LSM, in the
> YAMA module.
>
>

CAP_SYS_ADMIN is already used in the TIOCSTI TTY code to allow
character insertion into TTYs other than the caller's controlling
terminal. This is done because different TTYs indicate a security
boundary that should only be able to be crossed by a privileged
process. This patch would merely extend this security boundary
protection to include unprivileged processes from utilizing a common
TTY to step across a security boundary.

>
> - James
>

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[PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-04-19 05:50 +0200
  Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-04-19 07:00 +0200
    Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Kees Cook <keescook@chromium.org> - 2017-04-19 07:30 +0200
      Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-04-20 01:50 +0200
    Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-04-20 01:30 +0200
      Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-04-20 02:00 +0200
        Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-04-20 06:50 +0200
          Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-04-20 17:20 +0200
            Re: [kernel-hardening] Re: [PATCH] make TIOCSTI ioctl require  CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-04-20 17:30 +0200
            Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN matt@nmatt.com - 2017-04-20 19:20 +0200
              Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-04-20 19:50 +0200
                Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-04-21 07:20 +0200
                Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-04-21 07:30 +0200
                Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Kees Cook <keescook@chromium.org> - 2017-04-21 08:10 +0200
                Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-04-22 19:20 +0200
                Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-04-22 22:00 +0200
  Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN James Morris <jmorris@namei.org> - 2017-04-19 13:20 +0200
    Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-04-20 02:10 +0200

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