From: "H. Peter Anvin" <hpa@zytor.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: akpm@linux-foundation.org, serue@us.ibm.com,
viro@ftp.linux.org.uk, linuxram@us.ibm.com,
ebiederm@xmission.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, containers@lists.osdl.org
Subject: Re: [patch] unprivileged mounts update
Date: Wed, 25 Apr 2007 09:55:06 -0700 [thread overview]
Message-ID: <462F87EA.1000002@zytor.com> (raw)
In-Reply-To: <E1HgjG0-0005CN-00@dorka.pomaz.szeredi.hu>
Miklos Szeredi wrote:
>
> Andrew, please skip this patch, for now.
>
> Serge found a problem with the fsuid approach: setfsuid(nonzero) will
> remove filesystem related capabilities. So even if root is trying to
> set the "user=UID" flag on a mount, access to the target (and in case
> of bind, the source) is checked with user privileges.
>
> Root should be able to set this flag on any mountpoint, _regardless_
> of permissions.
>
Right, if you're using fsuid != 0, you're not running as root (fsuid is
the equivalent to euid for the filesystem.)
I fail to see how ruid should have *any* impact on mount(2). That seems
to be a design flaw.
-hpa
next prev parent reply other threads:[~2007-04-25 16:58 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-25 7:45 [patch] unprivileged mounts update Miklos Szeredi
2007-04-25 15:18 ` Miklos Szeredi
2007-04-25 16:55 ` H. Peter Anvin [this message]
2007-04-25 17:20 ` Serge E. Hallyn
2007-04-25 17:46 ` Eric W. Biederman
2007-04-25 17:56 ` Serge E. Hallyn
2007-04-25 18:41 ` Eric W. Biederman
2007-04-25 18:52 ` Serge E. Hallyn
2007-04-25 19:33 ` Miklos Szeredi
2007-04-26 14:57 ` Serge E. Hallyn
2007-04-26 15:23 ` Miklos Szeredi
2007-04-26 16:19 ` Serge E. Hallyn
2007-04-26 16:29 ` Miklos Szeredi
2007-04-26 19:42 ` Serge E. Hallyn
2007-04-26 19:56 ` Miklos Szeredi
2007-04-27 2:10 ` Serge E. Hallyn
2007-04-25 17:21 ` Eric W. Biederman
2007-04-25 17:30 ` Serge E. Hallyn
2007-04-26 19:10 ` Jan Engelhardt
2007-04-26 20:27 ` Miklos Szeredi
2007-04-27 4:10 ` Eric W. Biederman
2007-04-27 7:01 ` Jan Engelhardt
2007-04-25 19:33 ` Andrew Morton
2007-04-25 19:45 ` Miklos Szeredi
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