From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F5E2C04ABB for ; Tue, 11 Sep 2018 15:30:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B23A720866 for ; Tue, 11 Sep 2018 15:29:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B23A720866 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727161AbeIKU3q (ORCPT ); Tue, 11 Sep 2018 16:29:46 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33524 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726800AbeIKU3p (ORCPT ); Tue, 11 Sep 2018 16:29:45 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AB47CC12AF; Tue, 11 Sep 2018 15:29:56 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.34.27.30]) by smtp.corp.redhat.com (Postfix) with SMTP id EAC1AD1CE7; Tue, 11 Sep 2018 15:29:53 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 11 Sep 2018 17:29:56 +0200 (CEST) Date: Tue, 11 Sep 2018 17:29:53 +0200 From: Oleg Nesterov To: Kees Cook Cc: Rik van Riel , Michal Hocko , Stanislav Kozina , LKML Subject: Re: get_arg_page() && ptr_size accounting Message-ID: <20180911152953.GB9450@redhat.com> References: <20180910122907.GA23963@redhat.com> <20180910172109.GB27005@redhat.com> <20180910174355.GA27312@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Tue, 11 Sep 2018 15:29:56 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Tue, 11 Sep 2018 15:29:56 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'oleg@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/10, Kees Cook wrote: > > On Mon, Sep 10, 2018 at 10:43 AM, Oleg Nesterov wrote: > > > > with this patch > > > > #define MAX_ARG_STRINGS 0x7FFFFFFF > > > > doesn't match the reality. perhaps something like below makes sense just > > to make it clear, but this is cosmetic. > > Part of the discussion from back then was basically "we don't have > hard-coded limits so programs need to check dynamically themselves". > > I'd prefer to leave it all well enough alone since I don't want to > introduce regressions here in the face of the many many Stack Clash > style weaknesses. I simply can't understand... Perhaps you too misunderstood me, I only tried to say that count() can stop earlier, it is pointless to continue to count the arg/env strings after argc + envc > _STK_LIM / 4 * 3 / 2, copy_strings() will fail anyway. Oleg.