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=unavailable 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 26A7EC2BA19 for ; Wed, 15 Apr 2020 17:12:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D95921744 for ; Wed, 15 Apr 2020 17:12:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1416454AbgDORMh (ORCPT ); Wed, 15 Apr 2020 13:12:37 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:56942 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1416415AbgDORMQ (ORCPT ); Wed, 15 Apr 2020 13:12:16 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jOla5-0004e6-JQ; Wed, 15 Apr 2020 11:12:09 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jOla3-0001gx-82; Wed, 15 Apr 2020 11:12:09 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Richard Palethorpe , Kees Cook , linux-can@vger.kernel.org, netdev@vger.kernel.org, security@kernel.org, wg@grandegger.com, mkl@pengutronix.de, davem@davemloft.net References: <20200415113445.11881-1-sashal@kernel.org> <20200415113445.11881-68-sashal@kernel.org> Date: Wed, 15 Apr 2020 12:09:08 -0500 In-Reply-To: <20200415113445.11881-68-sashal@kernel.org> (Sasha Levin's message of "Wed, 15 Apr 2020 07:33:43 -0400") Message-ID: <87h7xkisln.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1jOla3-0001gx-82;;;mid=<87h7xkisln.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+wxNH2X5oEIwUT5tCdku1C684p3kocAA0= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH AUTOSEL 5.6 068/129] slcan: Don't transmit uninitialized stack data in padding X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org How does this differ from Greg's backports of this patches? Sasha Levin writes: > From: Richard Palethorpe > > [ Upstream commit b9258a2cece4ec1f020715fe3554bc2e360f6264 ] > > struct can_frame contains some padding which is not explicitly zeroed in > slc_bump. This uninitialized data will then be transmitted if the stack > initialization hardening feature is not enabled (CONFIG_INIT_STACK_ALL). > > This commit just zeroes the whole struct including the padding. > > Signed-off-by: Richard Palethorpe > Fixes: a1044e36e457 ("can: add slcan driver for serial/USB-serial CAN adapters") > Reviewed-by: Kees Cook > Cc: linux-can@vger.kernel.org > Cc: netdev@vger.kernel.org > Cc: security@kernel.org > Cc: wg@grandegger.com > Cc: mkl@pengutronix.de > Cc: davem@davemloft.net > Acked-by: Marc Kleine-Budde > Signed-off-by: David S. Miller > Signed-off-by: Sasha Levin > --- > drivers/net/can/slcan.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c > index a3664281a33fc..4dfa459ef5c73 100644 > --- a/drivers/net/can/slcan.c > +++ b/drivers/net/can/slcan.c > @@ -148,7 +148,7 @@ static void slc_bump(struct slcan *sl) > u32 tmpid; > char *cmd = sl->rbuff; > > - cf.can_id = 0; > + memset(&cf, 0, sizeof(cf)); > > switch (*cmd) { > case 'r': > @@ -187,8 +187,6 @@ static void slc_bump(struct slcan *sl) > else > return; > > - *(u64 *) (&cf.data) = 0; /* clear payload */ > - > /* RTR frames may have a dlc > 0 but they never have any data bytes */ > if (!(cf.can_id & CAN_RTR_FLAG)) { > for (i = 0; i < cf.can_dlc; i++) {