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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 9CE1DC33CB1 for ; Fri, 17 Jan 2020 07:20:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E84920748 for ; Fri, 17 Jan 2020 07:20:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729138AbgAQHUZ (ORCPT ); Fri, 17 Jan 2020 02:20:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:42358 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729121AbgAQHUZ (ORCPT ); Fri, 17 Jan 2020 02:20:25 -0500 Received: from goober.digi.com (acc1027289.lnk.telstra.net [149.135.16.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 84C962073A; Fri, 17 Jan 2020 07:20:23 +0000 (UTC) From: gerg@linux-m68k.org To: linux-m68k@vger.kernel.org Cc: Greg Ungerer Subject: [PATCH] m68knommu: fix memcpy() out of bounds warning in get_user() Date: Fri, 17 Jan 2020 17:20:05 +1000 Message-Id: <20200117072005.13923-1-gerg@linux-m68k.org> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-m68k-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-m68k@vger.kernel.org From: Greg Ungerer Newer versions of gcc are giving warnings in the non-MMU m68k version of the get_user() macro: ./arch/m68k/include/asm/string.h:72:25: warning: ‘__builtin_memcpy’ forming offset [3, 4] is out of the bounds [0, 2] of object ‘__gu_val’ with type ‘short unsigned int’ [-Warray-bounds] The warnings are generated when smaller sized variables are used as the result of user space pointers to larger values. For example a short/2-byte variable stores the result of a user space int (4-byte) pointer. The warning is in the 8-byte branch of get_user() - even though that branch is not the taken branch in the warning cases. Refactor the 8-byte branch of get_user() so that it uses a correctly formed union type to read and write the source and destination objects. Keep using the memcpy() just in case the user space pointer is not naturaly aligned. Signed-off-by: Greg Ungerer --- arch/m68k/include/asm/uaccess_no.h | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/arch/m68k/include/asm/uaccess_no.h b/arch/m68k/include/asm/uaccess_no.h index 0134008bf539..6bc80c35726d 100644 --- a/arch/m68k/include/asm/uaccess_no.h +++ b/arch/m68k/include/asm/uaccess_no.h @@ -71,26 +71,29 @@ extern int __put_user_bad(void); #define get_user(x, ptr) \ ({ \ int __gu_err = 0; \ - typeof(x) __gu_val = 0; \ switch (sizeof(*(ptr))) { \ case 1: \ - __get_user_asm(__gu_err, __gu_val, ptr, b, "=d"); \ + __get_user_asm(__gu_err, x, ptr, b, "=d"); \ break; \ case 2: \ - __get_user_asm(__gu_err, __gu_val, ptr, w, "=r"); \ + __get_user_asm(__gu_err, x, ptr, w, "=r"); \ break; \ case 4: \ - __get_user_asm(__gu_err, __gu_val, ptr, l, "=r"); \ + __get_user_asm(__gu_err, x, ptr, l, "=r"); \ break; \ - case 8: \ - memcpy((void *) &__gu_val, ptr, sizeof (*(ptr))); \ + case 8: { \ + union { \ + u64 l; \ + __typeof__(*(ptr)) t; \ + } __gu_val; \ + memcpy(&__gu_val.l, ptr, sizeof(__gu_val.l)); \ + (x) = __gu_val.t; \ break; \ + } \ default: \ - __gu_val = 0; \ __gu_err = __get_user_bad(); \ break; \ } \ - (x) = (typeof(*(ptr))) __gu_val; \ __gu_err; \ }) #define __get_user(x, ptr) get_user(x, ptr) -- 2.17.1