From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Serge E. Hallyn" Subject: Re: [PATCH] capabilities: Ambient capability set V1 Date: Mon, 23 Feb 2015 10:46:23 -0600 Message-ID: <20150223164623.GB32181@mail.hallyn.com> References: <20150223161625.GD25477@ubuntumail> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-api@vger.kernel.org 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/