From: Dave Chinner <david@fromorbit.com>
To: TongZhang <ztong@vt.edu>
Cc: 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 11:33:29 +1000 [thread overview]
Message-ID: <20180926013329.GD31060@dastard> (raw)
In-Reply-To: <5EF0D46A-C098-4B51-AD13-225FFCA35D4C@vt.edu>
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.
i.e. they are used to perform filesystem maintenance and extension
operations that need to be completely invisible to users from
userspace. e.g. online file defragmentation (xfs_fsr), data
migration (e.g. HSM products), efficient backup of data (xfsdump),
metadata and data scrubbing, online repair, etc.
IOWs, I really don't think these interfaces are something the LSMs
should be trying to intercept or audit, because they are essentially
internal filesystem interfaces used by trusted code and not general
user application facing APIs.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2018-09-26 1:33 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 [this message]
2018-09-26 13:23 ` Stephen Smalley
2018-09-27 2:08 ` Dave Chinner
2018-09-26 18:24 ` Alan Cox
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180926013329.GD31060@dastard \
--to=david@fromorbit.com \
--cc=darrick.wong@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=shenwenbosmile@gmail.com \
--cc=ztong@vt.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).