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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 F13BAC47404 for ; Wed, 9 Oct 2019 19:21:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D04D920B7C for ; Wed, 9 Oct 2019 19:21:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731734AbfJITVI (ORCPT ); Wed, 9 Oct 2019 15:21:08 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:51958 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728804AbfJITVI (ORCPT ); Wed, 9 Oct 2019 15:21:08 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.2 #3 (Red Hat Linux)) id 1iIHWD-000215-PY; Wed, 09 Oct 2019 19:21:05 +0000 Date: Wed, 9 Oct 2019 20:21:05 +0100 From: Al Viro To: Max Filippov Cc: linux-xtensa@linux-xtensa.org, linux-kernel@vger.kernel.org Subject: [PATCH] xtensa: fix {get,put}_user() for 64bit values Message-ID: <20191009192105.GC26530@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org First of all, on short copies __copy_{to,from}_user() return the amount of bytes left uncopied, *not* -EFAULT. get_user() and put_user() are expected to return -EFAULT on failure. Another problem is get_user(v32, (__u64 __user *)p); that should fetch 64bit value and the assign it to v32, truncating it in process. Current code, OTOH, reads 8 bytes of data and stores them at the address of v32, stomping on the 4 bytes that follow v32 itself. Signed-off-by: Al Viro -- diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h index 6792928ba84a..155174ddb7ae 100644 --- a/arch/xtensa/include/asm/uaccess.h +++ b/arch/xtensa/include/asm/uaccess.h @@ -100,7 +100,7 @@ do { \ case 4: __put_user_asm(x, ptr, retval, 4, "s32i", __cb); break; \ case 8: { \ __typeof__(*ptr) __v64 = x; \ - retval = __copy_to_user(ptr, &__v64, 8); \ + retval = __copy_to_user(ptr, &__v64, 8) ? -EFAULT : 0; \ break; \ } \ default: __put_user_bad(); \ @@ -198,7 +198,12 @@ do { \ case 1: __get_user_asm(x, ptr, retval, 1, "l8ui", __cb); break;\ case 2: __get_user_asm(x, ptr, retval, 2, "l16ui", __cb); break;\ case 4: __get_user_asm(x, ptr, retval, 4, "l32i", __cb); break;\ - case 8: retval = __copy_from_user(&x, ptr, 8); break; \ + case 8: { \ + __u64 __x = 0; \ + retval = __copy_from_user(&__x, ptr, 8) ? -EFAULT : 0; \ + (x) = *(__force __typeof__(*(ptr)) *) &__x; \ + break; \ + } \ default: (x) = __get_user_bad(); \ } \ } while (0)