From: Matt Brown <matt@nmatt.com>
To: Nick Kralevich <nnk@google.com>, Stephen Smalley <sds@tycho.nsa.gov>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
Casey Schaufler <casey@schaufler-ca.com>,
Boris Lukashev <blukashev@sempervictus.com>,
Greg KH <gregkh@linuxfoundation.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
Kees Cook <keescook@chromium.org>,
kernel-hardening@lists.openwall.com,
linux-security-module <linux-security-module@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [kernel-hardening] Re: [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN
Date: Tue, 30 May 2017 14:57:17 -0400 [thread overview]
Message-ID: <100b7d8c-7468-3122-4f59-3b0dcdf5dfc3@nmatt.com> (raw)
In-Reply-To: <CAFJ0LnHKKccbr-LqHHaFX5UNB20DzqfWDhvR-NTpgPedtkg0RA@mail.gmail.com>
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
next prev parent reply other threads:[~2017-05-30 18:57 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-29 21:37 [PATCH v7 0/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown
2017-05-29 21:37 ` [PATCH v7 1/2] security: tty: Add owner user namespace to tty_struct Matt Brown
2017-05-29 21:38 ` [PATCH v7 2/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN Matt Brown
2017-05-29 22:26 ` Alan Cox
2017-05-29 23:51 ` [kernel-hardening] " Boris Lukashev
2017-05-30 0:27 ` Casey Schaufler
2017-05-30 2:00 ` Matt Brown
2017-05-30 2:46 ` Casey Schaufler
2017-05-30 3:18 ` Matt Brown
2017-05-30 12:24 ` Alan Cox
2017-05-30 16:28 ` Matt Brown
2017-05-30 16:44 ` Daniel Micay
2017-05-30 18:32 ` Stephen Smalley
2017-05-30 18:44 ` Nick Kralevich
2017-05-30 18:57 ` Matt Brown [this message]
2017-05-30 20:22 ` Daniel Micay
2017-05-30 23:00 ` Matt Brown
2017-05-30 23:40 ` Daniel Micay
2017-05-30 23:59 ` Matt Brown
2017-05-30 22:51 ` Alan Cox
2017-05-30 23:19 ` Matt Brown
2017-05-30 23:56 ` Alan Cox
2017-06-01 2:35 ` Kees Cook
2017-06-01 13:08 ` Alan Cox
2017-06-01 17:18 ` Serge E. Hallyn
2017-06-01 21:26 ` Alan Cox
2017-06-01 18:58 ` Kees Cook
2017-06-01 21:24 ` Alan Cox
2017-06-02 14:46 ` Matt Brown
2017-06-02 15:36 ` Serge E. Hallyn
2017-06-02 16:02 ` Matt Brown
2017-06-02 16:57 ` Serge E. Hallyn
2017-06-02 17:32 ` Matt Brown
2017-06-02 18:18 ` Serge E. Hallyn
2017-06-02 19:22 ` Matt Brown
2017-06-02 19:25 ` Kees Cook
2017-06-02 19:26 ` Matt Brown
2017-06-02 20:05 ` Alan Cox
2017-06-02 20:11 ` Nick Kralevich
2017-06-02 20:46 ` Matt Brown
2017-06-03 22:00 ` Alan Cox
2017-06-03 22:22 ` Matt Brown
2017-06-04 3:37 ` Peter Dolding
2017-05-30 15:20 ` Casey Schaufler
2017-05-30 16:09 ` Matt Brown
2017-06-04 6:29 ` Boris Lukashev
2017-05-31 2:48 ` James Morris
2017-05-31 4:10 ` Matt Brown
2017-05-30 0:15 ` Matt Brown
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