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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 E9E39C0030C for ; Thu, 5 Sep 2019 14:20:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 741B621929 for ; Thu, 5 Sep 2019 14:11:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730236AbfIEOLP (ORCPT ); Thu, 5 Sep 2019 10:11:15 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:43047 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726048AbfIEOLP (ORCPT ); Thu, 5 Sep 2019 10:11:15 -0400 Received: from p5de0b6c5.dip0.t-ipconnect.de ([93.224.182.197] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1i5sTf-0002A9-IN; Thu, 05 Sep 2019 16:11:11 +0200 Date: Thu, 5 Sep 2019 16:11:10 +0200 (CEST) From: Thomas Gleixner To: Peter Zijlstra cc: LKML , Frederic Weisbecker , Oleg Nesterov , Ingo Molnar , Kees Cook Subject: Re: [patch 5/6] posix-cpu-timers: Sanitize thread clock permissions In-Reply-To: <20190905122108.GO2349@hirez.programming.kicks-ass.net> Message-ID: References: <20190905120339.561100423@linutronix.de> <20190905120540.068959005@linutronix.de> <20190905122108.GO2349@hirez.programming.kicks-ass.net> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 5 Sep 2019, Peter Zijlstra wrote: > On Thu, Sep 05, 2019 at 02:03:44PM +0200, Thomas Gleixner wrote: > > The thread clock permissions are restricted to tasks of the same thread > > group, but that also prevents a ptracer from reading them. This is > > inconsistent vs. the process restrictions and unnecessary strict. > > > > Relax it to ptrace permissions in the same way as process permissions are > > handled. > > More of a meta comment on the added permission checking; so where > clock_getcpuclockid() is allowed to return -EPERM, it doesn't because > that's in glibc and it has no clue. > > And these patches implement the ptrace checks and result in -EINVAL for > timer_create() and clock_gettime(), even though it should arguably be > -EPERM, but we're not allowed to return that here. Yeah. Maybe we should nevertheless. Thanks, tglx