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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 1ADFBC5DF63 for ; Wed, 6 Nov 2019 20:56:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E49D521A49 for ; Wed, 6 Nov 2019 20:56:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732380AbfKFU4r (ORCPT ); Wed, 6 Nov 2019 15:56:47 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:45258 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731910AbfKFU4q (ORCPT ); Wed, 6 Nov 2019 15:56:46 -0500 Received: from localhost ([127.0.0.1] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1iSSM6-00032c-Gz; Wed, 06 Nov 2019 21:56:42 +0100 Message-Id: <20191106202805.856479311@linutronix.de> User-Agent: quilt/0.65 Date: Wed, 06 Nov 2019 20:35:00 +0100 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Stephen Hemminger , Willy Tarreau , Juergen Gross , Sean Christopherson , Linus Torvalds , "H. Peter Anvin" Subject: [patch 1/9] x86/ptrace: Prevent truncation of bitmap size References: <20191106193459.581614484@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The active() callback of the IO bitmap regset divides the IO bitmap size by the word size (32/64 bit). As the I/O bitmap size is in bytes the active check fails for bitmap sizes of 1-3 bytes on 32bit and 1-7 bytes on 64bit. Use DIV_ROUND_UP() instead. Signed-off-by: Thomas Gleixner --- arch/x86/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -697,7 +697,7 @@ static int ptrace_set_debugreg(struct ta static int ioperm_active(struct task_struct *target, const struct user_regset *regset) { - return target->thread.io_bitmap_max / regset->size; + return DIV_ROUND_UP(target->thread.io_bitmap_max, regset->size); } static int ioperm_get(struct task_struct *target,