Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755461AbaJNSMh (ORCPT ); Tue, 14 Oct 2014 14:12:37 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:51940 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753601AbaJNSMg (ORCPT ); Tue, 14 Oct 2014 14:12:36 -0400 In-Reply-To: <1413296756-25071-5-git-send-email-seth.forshee@canonical.com> References: <1413296756-25071-1-git-send-email-seth.forshee@canonical.com> <1413296756-25071-5-git-send-email-seth.forshee@canonical.com> To: Seth Forshee Cc: "Eric W. Biederman" , fuse-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Miklos Szeredi , "Serge H. Hallyn" MIME-Version: 1.0 Subject: Re: [fuse-devel] [PATCH v4 4/5] fuse: Support privileged xattrs only with a mount option X-KeepSent: D40DA8DF:F78EA39D-86257D71:0057C4DC; type=4; name=$KeepSent X-Mailer: IBM Notes Release 9.0.1 October 14, 2013 From: Michael j Theall Message-ID: Date: Tue, 14 Oct 2014 13:12:26 -0500 X-MIMETrack: Serialize by Router on D03NM132/03/M/IBM(Release 9.0.1FP1|April 03, 2014) at 10/14/2014 12:12:28, Serialize complete at 10/14/2014 12:12:28 Content-Type: text/plain; charset="US-ASCII" X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14101418-0029-0000-0000-000004E7F423 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Seth Forshee wrote on 10/14/2014 09:25:55 AM: > From: Seth Forshee > To: Miklos Szeredi > Cc: fuse-devel@lists.sourceforge.net, "Serge H. Hallyn" > , linux-kernel@vger.kernel.org, Seth > Forshee , "Eric W. Biederman" > , linux-fsdevel@vger.kernel.org > Date: 10/14/2014 09:27 AM > Subject: [fuse-devel] [PATCH v4 4/5] fuse: Support privileged xattrs > only with a mount option > > Allowing unprivileged users to provide arbitrary xattrs via fuse > mounts bypasses the normal restrictions on setting xattrs. Such > mounts should be restricted to reading and writing xattrs in the > user.* namespace. > Can you explain how the normal restrictions on setting xattrs are bypassed? My filesystem still needs security.* and system.*, and it looks like xattr_permission already prevents non-privileged users from accessing trusted.* > It's difficult though to tell whether a mount is being performed > on behalf of an unprivileged user since fuse mounts are ususally > done via a suid root helper. Thus a new mount option, > privileged_xattrs, is added to indicated that xattrs from other > namespaces are allowed. This option can only be supplied by > system-wide root; supplying the option as an unprivileged user > will cause the mount to fail. I can't say I'm convinced that this is the right direction to head. Regards, Michael Theall -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/