From: ebiederm@xmission.com (Eric W. Biederman)
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ludwig Nussel <ludwig.nussel@suse.de>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Jan Kara <jack@suse.cz> (maintainer:EXT2 FILE SYSTEM),
Rob Landley <rob@landley.net> (maintainer:DOCUMENTATION),
Andrew Morton <akpm@linux-foundation.org> (maintainer:EXT3 FILE
SYSTEM),
Andreas Dilger <adilger.kernel@dilger.ca> (maintainer:EXT3 FILE
SYSTEM),
"Theodore Ts'o" <tytso@mit.edu> (maintainer:EXT4 FILE SYSTEM),
linux-ext4@vger.kernel.org (open list:EXT2 FILE SYSTEM),
linux-doc@vger.kernel.org (open list:DOCUMENTATION)
Subject: Re: [PATCH 1/3] implement uid and gid mount options for ext2
Date: Thu, 02 Aug 2012 06:00:55 -0700 [thread overview]
Message-ID: <87629130u0.fsf@xmission.com> (raw)
In-Reply-To: <20120802130642.46b12c59@pyramind.ukuu.org.uk> (Alan Cox's message of "Thu, 2 Aug 2012 13:06:42 +0100")
Alan Cox <alan@lxorguk.ukuu.org.uk> writes:
>> +uid=n[:m] Make all files appear to belong to uid n.
>> + Useful for e.g. removable media with fstab
>> + options 'user,uid=useruid'. The optional second
>> + uid m is actually written to the file system.
>
> So what happens if I insert a USB key containing a device node to the
> hard disk ? Why is this functionality useful in the current form ?
>
> (ie I think you need an actual rational security model first)
> Also why is this at the per fs level duplicating stuff each time rather
> than at the vfs level - this seems to be vfs level functionality.
Even more fun there is essentially a generic implementation in the user
namespaces. What needs to be implemented to support this is support for
mounting in a non-default user namespace, and then all of the mapping
functionality is generic. Which I presume will imply MS_NODEV.
Eric
next prev parent reply other threads:[~2012-08-02 13:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-02 11:54 [PATCH 0/3] implement uid and gid mount options for ext2, ext3 and ext4 Ludwig Nussel
2012-08-02 11:54 ` [PATCH 1/3] implement uid and gid mount options for ext2 Ludwig Nussel
2012-08-02 12:06 ` Alan Cox
2012-08-02 13:00 ` Eric W. Biederman [this message]
2012-08-02 11:54 ` [PATCH 2/3] implement uid and gid mount options for ext3 Ludwig Nussel
2012-08-02 11:54 ` [PATCH 3/3] implement uid and gid mount options for ext4 Ludwig Nussel
[not found] <1336660924-9598-1-git-send-email-ludwig.nussel@suse.d>
2012-05-11 11:10 ` [PATCH resend split 0/3] implement uid and gid mount options for ext2, ext3 and ext4 Ludwig Nussel
2012-05-11 11:10 ` [PATCH 1/3] implement uid and gid mount options for ext2 Ludwig Nussel
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