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, 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 C7B49C00523 for ; Wed, 8 Jan 2020 10:10:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A5D6D2070E for ; Wed, 8 Jan 2020 10:10:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727682AbgAHKKJ (ORCPT ); Wed, 8 Jan 2020 05:10:09 -0500 Received: from mga09.intel.com ([134.134.136.24]:52442 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726368AbgAHKKJ (ORCPT ); Wed, 8 Jan 2020 05:10:09 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jan 2020 02:10:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,409,1571727600"; d="scan'208";a="395696582" Received: from jochenh-mobl.ger.corp.intel.com (HELO kekkonen.fi.intel.com) ([10.252.51.76]) by orsmga005.jf.intel.com with ESMTP; 08 Jan 2020 02:10:06 -0800 Received: by kekkonen.fi.intel.com (Postfix, from userid 1000) id B38A021EDA; Wed, 8 Jan 2020 12:10:04 +0200 (EET) Date: Wed, 8 Jan 2020 12:10:04 +0200 From: Sakari Ailus To: Arnd Bergmann Cc: Mauro Carvalho Chehab , Hans Verkuil , syzbot+54fd8cca4b7226c94b8e@syzkaller.appspotmail.com, Ezequiel Garcia , Vandana BN , Boris Brezillon , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] media: v4l2-core: only zero-out ioctl-read buffers Message-ID: <20200108101004.GC4383@kekkonen.localdomain> References: <20200108100013.284108-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200108100013.284108-1-arnd@arndb.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 08, 2020 at 11:00:00AM +0100, Arnd Bergmann wrote: > The memset() got moved out of the check for _IOC_NONE, so passing a > made-up command number with a size but no direction would allow clearing > data on user-provided pointers. > > Move video_get_user() back into the _IOC_NONE check where it belongs. > > Reported-by: syzbot+54fd8cca4b7226c94b8e@syzkaller.appspotmail.com > Fixes: 6c625c01c7a6 ("media: v4l2-core: split out data copy from video_usercopy") > Signed-off-by: Arnd Bergmann Thanks for the fix, Arnd! Reviewed-by: Sakari Ailus > --- > drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c > index b0d670715c27..0f11fc6b5447 100644 > --- a/drivers/media/v4l2-core/v4l2-ioctl.c > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c > @@ -3208,12 +3208,12 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg, > parg = mbuf; > } > > + err = video_get_user((void __user *)arg, parg, orig_cmd, > + &always_copy); > + if (err) > + goto out; > } > > - err = video_get_user((void __user *)arg, parg, orig_cmd, &always_copy); > - if (err) > - goto out; > - > err = check_array_args(cmd, parg, &array_size, &user_ptr, &kernel_ptr); > if (err < 0) > goto out; -- Sakari Ailus sakari.ailus@linux.intel.com