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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 9EC98CA9EB9 for ; Sat, 26 Oct 2019 19:46:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7DA3320867 for ; Sat, 26 Oct 2019 19:46:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726553AbfJZTqP (ORCPT ); Sat, 26 Oct 2019 15:46:15 -0400 Received: from smtprelay0033.hostedemail.com ([216.40.44.33]:60078 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726350AbfJZTqP (ORCPT ); Sat, 26 Oct 2019 15:46:15 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay07.hostedemail.com (Postfix) with ESMTP id DA1B3181D341E; Sat, 26 Oct 2019 19:46:13 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: game48_1929a876a3b5b X-Filterd-Recvd-Size: 1608 Received: from XPS-9350.home (unknown [47.151.135.224]) (Authenticated sender: joe@perches.com) by omf10.hostedemail.com (Postfix) with ESMTPA; Sat, 26 Oct 2019 19:46:12 +0000 (UTC) Message-ID: Subject: [PATCH] kernel: sys.c: Avoid copying possible padding bytes in copy_to_user From: Joe Perches To: Andrew Morton Cc: LKML , Dan Carpenter , Julia Lawall , Thomas Gleixner Date: Sat, 26 Oct 2019 12:46:08 -0700 Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.34.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Joe Perches --- kernel/sys.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/sys.c b/kernel/sys.c index a611d1..3459a5 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1279,11 +1279,13 @@ SYSCALL_DEFINE1(uname, struct old_utsname __user *, name) 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);