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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 E1BE4C43603 for ; Thu, 5 Dec 2019 00:50:56 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A36F422B48 for ; Thu, 5 Dec 2019 00:50:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="r8AN03Eb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A36F422B48 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 579F96B0D70; Wed, 4 Dec 2019 19:50:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 52B096B0D91; Wed, 4 Dec 2019 19:50:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 41AA46B0D94; Wed, 4 Dec 2019 19:50:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0060.hostedemail.com [216.40.44.60]) by kanga.kvack.org (Postfix) with ESMTP id 28A9A6B0D70 for ; Wed, 4 Dec 2019 19:50:56 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id E4F4F180AD807 for ; Thu, 5 Dec 2019 00:50:55 +0000 (UTC) X-FDA: 76229258070.27.sugar14_8185d59e9c3e X-HE-Tag: sugar14_8185d59e9c3e X-Filterd-Recvd-Size: 2681 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Dec 2019 00:50:55 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9405E2053B; Thu, 5 Dec 2019 00:50:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575507054; bh=lH7P687besa4OGV/7OiHV6h7e1PEBTR5VnImDs+SfOw=; h=Date:From:To:Subject:In-Reply-To:From; b=r8AN03EbPXyY3GJ6gIq6wdmVYSSoh+IRu0G+PIqpN8i7twI0VTZV9z9z/f1WrAupw aQvBDdEAFoLhMzcU3ZYSSiZsxHGCdzNdspdxQjY/nadng/3PFHokJZJqZdX2qB/DzG RN3wY2K4CZ3E4u08iS/UmmK+rdKeDytMCa0WkJX8= Date: Wed, 04 Dec 2019 16:50:53 -0800 From: Andrew Morton To: akpm@linux-foundation.org, error27@gmail.com, joe@perches.com, julia.lawall@lip6.fr, keescook@chromium.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org Subject: [patch 23/86] kernel/sys.c: avoid copying possible padding bytes in copy_to_user Message-ID: <20191205005053.9loW-toi-%akpm@linux-foundation.org> In-Reply-To: <20191204164858.fe4ed8886e34ad9f3b34ea00@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Joe Perches Subject: kernel/sys.c: avoid copying possible padding bytes in copy_to_user Initialization is not guaranteed to zero padding bytes so use an explicit memset instead to avoid leaking any kernel content in any possible padding bytes. Link: http://lkml.kernel.org/r/dfa331c00881d61c8ee51577a082d8bebd61805c.camel@perches.com Signed-off-by: Joe Perches Cc: Dan Carpenter Cc: Julia Lawall Cc: Thomas Gleixner Cc: Kees Cook Signed-off-by: Andrew Morton --- kernel/sys.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/kernel/sys.c~kernel-sysc-avoid-copying-possible-padding-bytes-in-copy_to_user +++ a/kernel/sys.c @@ -1279,11 +1279,13 @@ SYSCALL_DEFINE1(uname, struct old_utsnam SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name) { - struct oldold_utsname tmp = {}; + struct oldold_utsname tmp; if (!name) return -EFAULT; + memset(&tmp, 0, sizeof(tmp)); + down_read(&uts_sem); memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN); memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN); _