Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753076AbbBWQq0 (ORCPT ); Mon, 23 Feb 2015 11:46:26 -0500 Received: from h2.hallyn.com ([78.46.35.8]:56735 "EHLO h2.hallyn.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753004AbbBWQqZ (ORCPT ); Mon, 23 Feb 2015 11:46:25 -0500 Date: Mon, 23 Feb 2015 10:46:23 -0600 From: "Serge E. Hallyn" To: Christoph Lameter Cc: Serge Hallyn , Serge Hallyn , Andy Lutomirski , Aaron Jones , "Ted Ts'o" , linux-security-module@vger.kernel.org, akpm@linuxfoundation.org, "Andrew G. Morgan" , Mimi Zohar , Austin S Hemmelgarn , Markku Savela , Jarkko Sakkinen , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Michael Kerrisk , Jonathan Corbet Subject: Re: [PATCH] capabilities: Ambient capability set V1 Message-ID: <20150223164623.GB32181@mail.hallyn.com> References: <20150223161625.GD25477@ubuntumail> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Content-Length: 1683 Lines: 37 On Mon, Feb 23, 2015 at 10:44:32AM -0600, Christoph Lameter wrote: > On Mon, 23 Feb 2015, Serge Hallyn wrote: > > > The core concern for amorgan is that an unprivileged user not be > > able to cause a privileged program to run in a way that it fails to > > drop privilege before running unprivileged-user-provided code. > > I do not see a problem with dropping privilege since the ambient set > is supposed to be preserved across a drop of priviledge. Because you're tricking the program into thinking it has dropped the privilege, when in fact it has not. > > Since your desire is precisely for a mode where dropping privilege > > works as usual, but exec then re-gains some or all of that privilege, > > I would say that the ambient set stays active even if the setuid binary > drops to regular perms. > > > we need to either agree on a way to enter that mode that ordinary > > use caes can't be tricked into using, or find a way for legacy > > users to be tpiped off as to what's going on (without having to be > > re-written) > > Well if the ambient set is completely separate then the existing > semantics are preserved while the ambient set stays active as intended. > > -- > 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/ -- 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/