Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Tue, 30 May 2017 19:59:12 -0400
From: Matt Brown <>
To: Daniel Micay <>, Nick Kralevich <>,
 Stephen Smalley <>, Alan Cox <>,
 Kees Cook <>
Cc: Casey Schaufler <>,
 Boris Lukashev <>,
 Greg KH <>, "Serge E. Hallyn" <>,,
 linux-security-module <>,
 linux-kernel <>
Subject: Re: Re: [PATCH v7 2/2] security: tty: make TIOCSTI
 ioctl require CAP_SYS_ADMIN

On 5/30/17 7:40 PM, Daniel Micay wrote:
> On Tue, 2017-05-30 at 19:00 -0400, Matt Brown wrote:
>> On 5/30/17 4:22 PM, Daniel Micay wrote:
>>>> 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.
>>> Since there's a capable LSM hook for ioctl already, it means it
>>> could go
>>> in Yama with ptrace_scope but core kernel code would still need to
>>> be
>>> changed to track the owning tty. I think Yama vs. core kernel
>>> shouldn't
>>> matter much anymore due to stackable LSMs.
>> What does everyone think about a v8 that moves this feature under Yama
>> and uses
>> the file_ioctl LSM hook?
> It would only make a difference if it could be fully contained there, as
> in not depending on tracking the tty owner.

For the reasons discussed earlier (to allow for nested containers where one of
the containers is privileged) we want to track the user namespace that owns the tty.

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.