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 7FEBBECDE47 for ; Thu, 25 Oct 2018 13:01:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 508602082D for ; Thu, 25 Oct 2018 13:01:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 508602082D 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-security-module-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727416AbeJYVeO (ORCPT ); Thu, 25 Oct 2018 17:34:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49422 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727125AbeJYVeO (ORCPT ); Thu, 25 Oct 2018 17:34:14 -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 385F03003BD9; Thu, 25 Oct 2018 13:01:34 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.106]) by smtp.corp.redhat.com (Postfix) with SMTP id 733F218A6F; Thu, 25 Oct 2018 13:01:32 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 25 Oct 2018 15:01:32 +0200 (CEST) Date: Thu, 25 Oct 2018 15:01:30 +0200 From: Oleg Nesterov To: Tetsuo Handa Cc: serge@hallyn.com, syzbot , jmorris@namei.org, keescook@chromium.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: KASAN: use-after-free Read in task_is_descendant Message-ID: <20181025130129.GE3725@redhat.com> References: <76013c9e-0664-ef5e-b6c0-d48f6ce5db3c@i-love.sakura.ne.jp> <20181022134634.GA7358@redhat.com> <201810250215.w9P2Fm2M078167@www262.sakura.ne.jp> <20181025111355.GA3725@redhat.com> <20181025121709.GD3725@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181025121709.GD3725@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Thu, 25 Oct 2018 13:01:34 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 10/25, Oleg Nesterov wrote: > > As I said below, please ignore ptracer_exception_found(), another caller for now, > perhaps it needs some changes too. I even have a vague feeling that I have already > blamed this function some time ago... Heh, yes, 3 years ago ;) https://lore.kernel.org/lkml/20150106184427.GA18153@redhat.com/ I can't understand my email today, but note that I tried to point out that task_is_descendant() can dereference the freed mem. And yes, task_is_descendant() is overcompicated for no reason, afaics. Oleg.