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=-5.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 6AAF2C43466 for ; Sat, 19 Sep 2020 20:17:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 349DC21D42 for ; Sat, 19 Sep 2020 20:17:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dswyVVpW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726582AbgISURq (ORCPT ); Sat, 19 Sep 2020 16:17:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726511AbgISURq (ORCPT ); Sat, 19 Sep 2020 16:17:46 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15035C0613CE; Sat, 19 Sep 2020 13:17:46 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id k8so5734093pfk.2; Sat, 19 Sep 2020 13:17:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=nufqMxRxzBynEUzPSmKE11m5kNg4+eB3mixf5Nnih4E=; b=dswyVVpWzVbiP2kS5AD/QD8cHzI45lM/MxkySFRQSVYmP2C8cVcZnsoIUHMkeP0p6/ NlTrTAXVIQGKSljeVEQhU+rnZwZ3C/3m2dB4u56v+olo8gfT5B9MdaXdKTVwCBBXSfso d5Z4wDdJJBRlamEyPm/YjKSiZ8yioEkioxLfq+AigV1SPZ/xhfZr0jOIVyYzat9wDWYC 51w3q3tm5bQ7RG8qzu+7WpdTHbkb0eyDyFpKSEapx3qUPx39/PPaLOEEJuICYPy02oWM UnjgNwiJitmwsUd5YiujlNl9YLxZIOY8BPW9NDqyDoHD3//eqchZuhpJIFz3Tx97SysN eKpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=nufqMxRxzBynEUzPSmKE11m5kNg4+eB3mixf5Nnih4E=; b=L7q3f+lVdQWz5koVnjAq++F2J045zwW+UsnLWFb2cdoChW+tdV9g2b7PeM4nG+OdqA 0WVyNt7Ssad8I2VFRgattaVfuMbenElb2M/sCD7nL/F96amVb413wNm0LVg/aVRVtUU1 pJhuXPep9Adfd/UPkSyAFUUqyHmERBVH/MoZ627oVBdLRoPIOjJTP5AROPohdLhWq8D0 drNLTPK3ipjC+bjKsOcI9iPWCfeWK5ba9KM4y1uKhNWoorlh0+nSnJTfGNUURNObHY68 /zRSynaIk22FZq1M0hk3hR5CqAuDxCv5uoUn0AXQ3JsRylWCgjvE5HZhEwGZCu/7XY9s UNyQ== X-Gm-Message-State: AOAM532ORsq3/aD383vrB/oD9QGONCSOLttvFL78oT3KQyns55nMvScT i3nsadjXVV57YNGdX8ndoPEmRmUWhO3FMTvfj+A= X-Google-Smtp-Source: ABdhPJwmaLvMmQ0FhJwwhvT/7QRl99Kv7dcwIDpJdJkJ/7+mObcFcvLUIlKkLC9FIB3sn+NWTWMmwg== X-Received: by 2002:aa7:8aca:0:b029:13e:d13d:a07d with SMTP id b10-20020aa78aca0000b029013ed13da07dmr37930221pfd.20.1600546664624; Sat, 19 Sep 2020 13:17:44 -0700 (PDT) Received: from [192.168.0.104] ([49.207.212.24]) by smtp.gmail.com with ESMTPSA id d20sm6371822pjv.39.2020.09.19.13.17.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Sep 2020 13:17:43 -0700 (PDT) Subject: Re: [Linux-kernel-mentees] [PATCH] fs: fix KMSAN uninit-value bug by initializing nd in do_file_open_root From: Anant Thazhemadam To: Al Viro , Greg KH Cc: Eric Biggers , linux-fsdevel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, syzbot+4191a44ad556eacc1a7a@syzkaller.appspotmail.com, linux-kernel@vger.kernel.org References: <20200916052657.18683-1-anant.thazhemadam@gmail.com> <20200916054157.GC825@sol.localdomain> <20200917002238.GO3421308@ZenIV.linux.org.uk> <20200919144451.GF2712238@kroah.com> <20200919161727.GG3421308@ZenIV.linux.org.uk> <20200919165558.GH3421308@ZenIV.linux.org.uk> <26d881e5-f68a-b3b7-4cb0-04a3c6c384ac@gmail.com> Message-ID: Date: Sun, 20 Sep 2020 01:47:39 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.2.2 MIME-Version: 1.0 In-Reply-To: <26d881e5-f68a-b3b7-4cb0-04a3c6c384ac@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 19-09-2020 17:03, Anant Thazhemadam wrote: > On 19-09-2020 22:25, Al Viro wrote: >> On Sat, Sep 19, 2020 at 05:17:27PM +0100, Al Viro wrote: >> >>> Lovely... That would get an empty path and non-directory for a starting >>> point, but it should end up with LAST_ROOT in nd->last_type. Which should >>> not be able to reach the readers of those fields... Which kernel had >>> that been on? >> Yecchhh... I see what's going on; I suspect that this ought to be enough. >> Folks, could somebody test it on the original reproducer setup? > Sure. I can do that. Looks like this patch actually fixes this bug. I made syzbot test the patch, and no issues were triggered! Note:    syzbot tested the patch with the KMSAN kernel, which was recently rebased on v5.9-rc4. Thanks, Anant