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Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN

From Matt Brown <matt@nmatt.com>
Newsgroups linux.kernel
Subject Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN
Date 2017-05-30 21:00 +0200
Message-ID <tMUx3-2xi-15@gated-at.bofh.it> (permalink)
References (7 earlier) <tMFRn-1q5-5@gated-at.bofh.it> <tMOrE-7i1-25@gated-at.bofh.it> <tMSbU-1dJ-19@gated-at.bofh.it> <tMU41-2mV-7@gated-at.bofh.it> <tMUnn-2tM-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 5/30/17 2:44 PM, Nick Kralevich wrote:
> On Tue, May 30, 2017 at 11:32 AM, Stephen Smalley <sds@tycho.nsa.gov> wrote:
>>> Seccomp requires the program in question to "opt-in" so to speak and
>>> set
>>> certain restrictions on itself. However as you state above, any
>>> TIOCSTI
>>> protection doesn't matter if the program correctly allocates a
>>> tty/pty pair.
>>> This protections seeks to protect users from programs that don't do
>>> things
>>> correctly. Rather than killing bugs, this feature attempts to kill an
>>> entire
>>> bug class that shows little sign of slowing down in the world of
>>> containers and
>>> sandboxes.
>>
>> Just FYI, you can also restrict TIOCSTI (or any other ioctl command)
>> via SELinux ioctl whitelisting, and Android is using that feature to
>> restrict TIOCSTI usage in Android O (at least based on the developer
>> previews to date, also in AOSP master).
> 
> For reference, this is https://android-review.googlesource.com/306278
> , where we moved to a whitelist for handling ioctls for ptys.
> 
> -- Nick
> 

Thanks, I didn't know that android was doing this. I still think this feature
is worthwhile for people to be able to harden their systems against this attack
vector without having to implement a MAC.

Matt

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[PATCH v7 2/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-29 23:40 +0200
  Re: [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require  CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-05-30 00:30 +0200
    Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Boris Lukashev <blukashev@sempervictus.com> - 2017-05-30 02:00 +0200
      Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Casey Schaufler <casey@schaufler-ca.com> - 2017-05-30 02:30 +0200
        Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-30 04:10 +0200
          Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Casey Schaufler <casey@schaufler-ca.com> - 2017-05-30 04:50 +0200
            Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-30 05:20 +0200
              Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-05-30 14:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-30 18:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Daniel Micay <danielmicay@gmail.com> - 2017-05-30 18:50 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Stephen Smalley <sds@tycho.nsa.gov> - 2017-05-30 20:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Nick Kralevich <nnk@google.com> - 2017-05-30 20:50 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-30 21:00 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Daniel Micay <danielmicay@gmail.com> - 2017-05-30 22:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-31 01:10 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Daniel Micay <danielmicay@gmail.com> - 2017-05-31 01:50 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-31 02:00 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-05-31 01:00 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-31 01:20 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-05-31 02:00 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Kees Cook <keescook@chromium.org> - 2017-06-01 04:40 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-06-01 15:10 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-06-01 19:20 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-06-01 23:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Kees Cook <keescook@chromium.org> - 2017-06-01 21:00 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-06-01 23:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-06-02 16:50 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-06-02 17:40 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-06-02 18:10 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-06-02 19:00 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-06-02 19:40 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN "Serge E. Hallyn" <serge@hallyn.com> - 2017-06-02 20:20 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-06-02 21:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Kees Cook <keescook@chromium.org> - 2017-06-02 21:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-06-02 21:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-06-02 22:10 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Nick Kralevich <nnk@google.com> - 2017-06-02 22:20 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-06-02 22:50 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make  TIOCSTI ioctl require CAP_SYS_ADMIN Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-06-04 00:10 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-06-04 00:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Peter Dolding <oiaohm@gmail.com> - 2017-06-04 05:40 +0200
              Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Casey Schaufler <casey@schaufler-ca.com> - 2017-05-30 17:30 +0200
                Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-30 18:10 +0200
        Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Boris Lukashev <blukashev@sempervictus.com> - 2017-06-04 08:30 +0200
      Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN James Morris <jmorris@namei.org> - 2017-05-31 04:50 +0200
        Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI  ioctl require CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-31 06:20 +0200
    Re: [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require  CAP_SYS_ADMIN Matt Brown <matt@nmatt.com> - 2017-05-30 02:20 +0200

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