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=-9.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E501CC433E0 for ; Mon, 10 Aug 2020 09:08:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3245206B5 for ; Mon, 10 Aug 2020 09:08:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597050507; bh=lJPq5ETxHPZ0RoMNhAnC8Tl6vZT66KDQarRsEygWibM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=kdR7CGRlqPQsTiG7DS4eShySNhgLdupXBivkezsZGPKAr+h0sfgz38XGt8JSZh5AB wsqE6xbr7EMDPzkrXDor3RGc/9b5nS5KPOkG12p8ohcSkpL4Fa5zSLGZYu6PiFM+oC fbAItlVaWGIDTfzguC/04gzi3Oy76oWq3Uql07tU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726177AbgHJJIY (ORCPT ); Mon, 10 Aug 2020 05:08:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:34076 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726021AbgHJJIX (ORCPT ); Mon, 10 Aug 2020 05:08:23 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 578B9206B5; Mon, 10 Aug 2020 09:08:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597050502; bh=lJPq5ETxHPZ0RoMNhAnC8Tl6vZT66KDQarRsEygWibM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SPNk10mhV3Z9sVkCmr79SktXZo76Dck7IItQ4xzcqZ70UuvqrAI0mz1z+ZnIzgbU8 X2VffCf2KC79hHcy/0SJFqlKsDaB3GBSoDEPhel6x87RuC673xH9UzPxQO4jYzfV3l NKLn3qbeRcF6yAoHcy9OGOIi7Um2UTvMcgXh4BZo= Date: Mon, 10 Aug 2020 11:08:33 +0200 From: Greg KH To: Dmitry Vyukov Cc: syzbot , Andrey Konovalov , balbi@kernel.org, Dan Carpenter , Alexander Potapenko , LKML , USB list , syzkaller-bugs Subject: Re: KMSAN: kernel-infoleak in raw_ioctl Message-ID: <20200810090833.GA2271719@kroah.com> References: <000000000000ce85c405ac744ff6@google.com> <20200810074706.GD1529187@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Mon, Aug 10, 2020 at 11:00:07AM +0200, Dmitry Vyukov wrote: > On Mon, Aug 10, 2020 at 9:46 AM Greg KH wrote: > > > > On Sun, Aug 09, 2020 at 09:27:18AM -0700, syzbot wrote: > > > Hello, > > > > > > syzbot found the following issue on: > > > > > > HEAD commit: ce8056d1 wip: changed copy_from_user where instrumented > > > git tree: https://github.com/google/kmsan.git master > > > console output: https://syzkaller.appspot.com/x/log.txt?x=141eb8b2900000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=3afe005fb99591f > > > dashboard link: https://syzkaller.appspot.com/bug?extid=a7e220df5a81d1ab400e > > > compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) > > > userspace arch: i386 > > > > > > Unfortunately, I don't have any reproducer for this issue yet. > > > > The irony of a kernel module written for syzbot testing, causing syzbot > > reports.... > > The raw gadget and KCOV are also kernel code and subject to all the > same rules as any other kernel code from syzkaller point of view. > > But I think the root cause of this bug is the origin of the uninitialized-ness: > > Local variable ----buf.i@asix_get_phy_addr created at: > asix_read_cmd drivers/net/usb/asix_common.c:312 [inline] > asix_read_phy_addr drivers/net/usb/asix_common.c:295 [inline] > asix_get_phy_addr+0x4d/0x290 drivers/net/usb/asix_common.c:314 > asix_read_cmd drivers/net/usb/asix_common.c:312 [inline] > asix_read_phy_addr drivers/net/usb/asix_common.c:295 [inline] > asix_get_phy_addr+0x4d/0x290 drivers/net/usb/asix_common.c:314 read buffers sent to USB hardware are ment to be filled in by the hardware with the data received from it, we do not zero-out those buffers before passing the pointer there. Perhaps with testing frameworks like the raw usb controller, that might cause a number of false-positives to happen? thanks, greg k-h