From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757002AbdLWQD7 (ORCPT ); Sat, 23 Dec 2017 11:03:59 -0500 Received: from shards.monkeyblade.net ([184.105.139.130]:53676 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752651AbdLWQD6 (ORCPT ); Sat, 23 Dec 2017 11:03:58 -0500 Date: Sat, 23 Dec 2017 11:03:56 -0500 (EST) Message-Id: <20171223.110356.169739765604909704.davem@davemloft.net> To: alexei.starovoitov@gmail.com Cc: jannh@google.com, netdev@vger.kernel.org, daniel@iogearbox.net, ben@decadent.org.uk, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: kasan for bpf From: David Miller In-Reply-To: <20171223043155.biljcns7iwe7n633@ast-mbp> References: <20171223022617.GO2971@decadent.org.uk> <20171223043155.biljcns7iwe7n633@ast-mbp> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sat, 23 Dec 2017 08:03:57 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexei Starovoitov Date: Fri, 22 Dec 2017 20:31:56 -0800 > Thoughts? Even though you propose it as the opposite, it sounds like a crutch for the verifier. If we strictly control objects that the eBPF program can access, verifier ensures this, and all other objects go through helpers, then I cannot see what kasan for bpf can buy us. To me it tells the world "yes, verifier and carefully designed helpers are insufficient" and that's not the message I have been giving to rooms full of hundreds of people listening to my xdp/bpf presentations.