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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 A7234C49ED9 for ; Tue, 10 Sep 2019 17:59:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A08221479 for ; Tue, 10 Sep 2019 17:59:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728113AbfIJR7O (ORCPT ); Tue, 10 Sep 2019 13:59:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13369 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726524AbfIJR7O (ORCPT ); Tue, 10 Sep 2019 13:59:14 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2A90DA2667D; Tue, 10 Sep 2019 17:59:14 +0000 (UTC) Received: from asgard.redhat.com (ovpn-112-20.ams2.redhat.com [10.36.112.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9EC3660BF3; Tue, 10 Sep 2019 17:59:06 +0000 (UTC) Date: Tue, 10 Sep 2019 18:58:39 +0100 From: Eugene Syromiatnikov To: linux-kernel@vger.kernel.org, Christian Brauner , Oleg Nesterov Cc: Andrew Morton , "Peter Zijlstra (Intel)" , Ingo Molnar , "Dmitry V. Levin" , Eric Biederman Subject: [PATCH v2] fork: check exit_signal passed in clone3() call Message-ID: <20190910175839.GA27330@asgard.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.68]); Tue, 10 Sep 2019 17:59:14 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. After some consideration, I've decided to utilise Oleg's proposal[1] "(args.exit_signal & ~((u64)CSIGNAL))" as a check. I still don't like it, as it mixes argument copy check (I'm not sure if it's ever needed, however, as I'm not sure if there's a reason for exit_signal field of struct kernel_clone_args to have int type) with argument sanity check; moreover, it covers only clone3 case, and the code in copy_process is still error-prone in the long run. Ideally, the check should be somewhere in the one place, but as of now this one place is likely _do_fork, but it's kinda weir to have argument check there as of now. Changes since v1[2]: - Check changed to comparison against negated CSIGNAL to address the bug reported by Oleg[3]. - Added a comment to _do_fork that exit_signal has to be checked by the caller. [1] https://lkml.org/lkml/2019/9/10/581 [2] https://lkml.org/lkml/2019/9/10/411 [3] https://lkml.org/lkml/2019/9/10/467 Eugene Syromiatnikov (1): fork: check exit_signal passed in clone3() call kernel/fork.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) -- 2.1.4