Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751481AbaKKOE6 (ORCPT ); Tue, 11 Nov 2014 09:04:58 -0500 Received: from mail-wi0-f172.google.com ([209.85.212.172]:57805 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751022AbaKKOE4 (ORCPT ); Tue, 11 Nov 2014 09:04:56 -0500 Date: Tue, 11 Nov 2014 15:04:54 +0100 From: Miklos Szeredi To: Seth Forshee Cc: "Eric W. Biederman" , "Serge H. Hallyn" , Andy Lutomirski , Michael j Theall , fuse-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v5 2/4] fuse: Support fuse filesystems outside of init_user_ns Message-ID: <20141111140454.GD333@tucsk> References: <1414013060-137148-1-git-send-email-seth.forshee@canonical.com> <1414013060-137148-3-git-send-email-seth.forshee@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1414013060-137148-3-git-send-email-seth.forshee@canonical.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 22, 2014 at 04:24:18PM -0500, Seth Forshee wrote: > Update fuse to translate uids and gids to/from the user namspace > of the process servicing requests on /dev/fuse. Any ids which do > not map into the namespace will result in errors. inodes will > also be marked bad when unmappable ids are received from > userspace. Okay. > Due to security concerns the namespace used should be fixed, > otherwise a user might be able to gain elevated privileges or > influence processes that the user would otherwise be unable to > manipulate. Thus the namespace of the mounting process is used > for all translations, and this namespace is required to be the > same as the one in use when /dev/fuse was opened. Maybe I'm being dense, but can someone give a concrete example of such an attack? That might also help me understand how exactly user/pid namespaces work... Patch otherwise looks okay. Thanks, Miklos -- 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/