linux-kernel - Re: [PATCH v4 1/2] tiocsti-restrict : Add owner user namespace to tty

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Message-ID: <12d91b0b-0aa9-a0d5-7cb4-83371e0e8749@nmatt.com>
Date:   Wed, 3 May 2017 16:02:55 -0400
From:   Matt Brown <matt@...tt.com>
To:     Greg KH <gregkh@...uxfoundation.org>,
        Kees Cook <keescook@...omium.org>
Cc:     "Serge E. Hallyn" <serge@...lyn.com>,
        James Morris <jmorris@...ei.org>, Jiri Slaby <jslaby@...e.com>,
        Jonathan Corbet <corbet@....net>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Jann Horn <jannh@...gle.com>,
        "kernel-hardening@...ts.openwall.com" 
        <kernel-hardening@...ts.openwall.com>,
        linux-security-module <linux-security-module@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>
Subject: Re: [PATCH v4 1/2] tiocsti-restrict : Add owner user namespace to
 tty_struct

On 05/03/2017 03:45 PM, Greg KH wrote:
> On Wed, May 03, 2017 at 12:32:07PM -0700, Kees Cook wrote:
>> On Mon, Apr 24, 2017 at 6:57 AM, Serge E. Hallyn <serge@...lyn.com> wrote:
>>> Quoting Matt Brown (matt@...tt.com):
>>>> This patch adds struct user_namespace *owner_user_ns to the tty_struct.
>>>> Then it is set to current_user_ns() in the alloc_tty_struct function.
>>>>
>>>> This is done to facilitate capability checks against the original user
>>>> namespace that allocated the tty.
>>>>
>>>> E.g. ns_capable(tty->owner_user_ns,CAP_SYS_ADMIN)
>>>>
>>>> This combined with the use of user namespace's will allow hardening
>>>> protections to be built to mitigate container escapes that utilize TTY
>>>> ioctls such as TIOCSTI.
>>>>
>>>> See: https://bugzilla.redhat.com/show_bug.cgi?id=1411256
>>>>
>>>> Signed-off-by: Matt Brown <matt@...tt.com>
>>>
>>> Acked-by: Serge Hallyn <serge@...lyn.com>
>>
>> This Ack didn't end up in the v5, but I think it stands, yes?
>>
>> Greg, is the v5 okay to pull for you or would a v6 with Acks/Reviews
>> included be preferred?
>
> v6 would be great, and we are dropping patch 2 from the series, right?
> I was expecting this to be resent.  I'll start looking at new patches
> like this after 4.12-rc1 is out.
>

I will create a v6 with the Acks/Reviews. I'd like to keep patch 2 in
since that got acked by at least Serge. (Kees also? or just patch 1?)

> thanks,
>
> greg k-h
>