From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Dave Chinner <david@fromorbit.com>
Cc: TongZhang <ztong@vt.edu>,
darrick.wong@oracle.com, linux-xfs@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
linux-security-module@vger.kernel.org,
Wenbo Shen <shenwenbosmile@gmail.com>
Subject: Re: Leaking Path in XFS's ioctl interface(missing LSM check)
Date: Wed, 26 Sep 2018 19:24:26 +0100 [thread overview]
Message-ID: <20180926192426.472360ea@alans-desktop> (raw)
In-Reply-To: <20180926013329.GD31060@dastard>
On Wed, 26 Sep 2018 11:33:29 +1000
Dave Chinner <david@fromorbit.com> wrote:
> On Tue, Sep 25, 2018 at 08:51:50PM -0400, TongZhang wrote:
> > Hi,
> >
> > I'm bringing up this issue again to let of LSM developers know the situation, and would like to know your thoughts.
> > Several weeks ago I sent an email to the security list to discuss the issue where
> > XFS's ioctl interface can do things like vfs_readlink without asking LSM's
> > permission, which we think is kind of weird and this kind of operation should be
> > audited by LSM.
>
> These aren't user interfaces. They are filesystem maintenance and
> extension interfaces. They are intended for low level filesystem
> utilities that require complete, unrestricted access to the
> underlying filesystem via holding CAP_SYSADMIN in the initns.
CAP_SYS_ADMIN is meaningless in an environment using a strong LSM set up.
So what if I have CAP_SYS_ADMIN ? In a secure environment low level
complete unrestricted access to the file system is most definitely
something that should be mediated.
CAP_SYS_ADMIN is also a bit weird because low level access usually
implies you can bypass access controls so you should also check
CAP_SYS_DAC ?
Alan
next prev parent reply other threads:[~2018-09-26 18:24 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 0:51 Leaking Path in XFS's ioctl interface(missing LSM check) TongZhang
2018-09-26 1:33 ` Dave Chinner
2018-09-26 13:23 ` Stephen Smalley
2018-09-27 2:08 ` Dave Chinner
2018-09-26 18:24 ` Alan Cox [this message]
2018-09-27 1:38 ` Dave Chinner
2018-09-27 21:23 ` James Morris
2018-09-27 22:19 ` Dave Chinner
2018-09-27 23:12 ` Tetsuo Handa
2018-09-30 14:16 ` Alan Cox
2018-10-01 0:25 ` Dave Chinner
2018-10-01 15:04 ` Alan Cox
2018-10-01 15:25 ` Theodore Y. Ts'o
2018-10-01 22:53 ` Dave Chinner
2018-10-01 15:44 ` Darrick J. Wong
2018-10-01 20:08 ` James Morris
2018-10-01 22:45 ` Dave Chinner
2018-10-02 19:20 ` James Morris
2018-10-02 22:42 ` Dave Chinner
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