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=-7.1 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,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 D2530C433DF for ; Sat, 1 Aug 2020 19:48:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A66BE206E9 for ; Sat, 1 Aug 2020 19:48:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="cxXfQUbd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725939AbgHATsu (ORCPT ); Sat, 1 Aug 2020 15:48:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725883AbgHATst (ORCPT ); Sat, 1 Aug 2020 15:48:49 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D252FC06174A; Sat, 1 Aug 2020 12:48:49 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id g19so6306634plq.0; Sat, 01 Aug 2020 12:48:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=D/zKsPT50/brRt6TQ94qvPI8VW7jt5RqidXgO91dbKA=; b=cxXfQUbdWAv5Q1PSHtTmYyxr4TWeAH2VpZs7yypxRFxoctSqlLGqImL3/wJeRI12SP 9jbrwT1oRJSvTo1cxVm8JCLGKMn7uk5KWjYBnS7pE1IvV9jSsl/xS7XwWXP0Xs1DuIe2 wD358QjSfLvbk5nq/ND1+Jen8VIKBNTOMhkVP3314bv+0TAf3+MjWWHSYlDPzUJtf0xC po7jVaP3lakpIkxsnqw9NbhGx56vxinDxhwEWADfqMgdgOek8KHSr2+aCp4Az+ioByS1 cYVspwvAEByNv+oC8uBj/CSSh2usnS4RJ6ibkM3z1Ndwt7/xTo3sLq/vLJbsvL4k5iHb gc0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=D/zKsPT50/brRt6TQ94qvPI8VW7jt5RqidXgO91dbKA=; b=t+XtR1cTQ1RHKU7a5LkbS5YgF/uveafTqtmpa3J3q4vxCpKPtYHGlWaxp7lqjlK5wj PoIMSCKIdT+LOcIYM+99zCJUFTC8xDWlKXkALVw8NJq+EDoAxnbsw1IBigMFGK398C/b vxCccLbuiIwVnUvcMwcpn1969JIyf0ITGyqRyJbwl2aYUu9wF4yprhLbbJ7tx5xnnMZB Ro2lY/f09H9WlWgM+cDLUS1wpoetWwMgAGykXfZ9O4jAiPLhUjGO/kvg8sbXJG4tJXgM JPqsFdPrKqunzrOyp+qNkC1dW8cU9Jx2F9lqWGVeLtsVbyOh8+gFtOq03GDv0GkkO8w8 q+0g== X-Gm-Message-State: AOAM532BMZuouSMKvd+9jtCom2fogPJCw9/A8Wk+xJAZL9FSXYm6nKq5 KDUQaPTldJvhi1k7bY2WfO8= X-Google-Smtp-Source: ABdhPJyZmsSRAtwKHUgKvrRVZquGxxpXMiTCw6T+Na+Re7YXxks6NrlDC9q5U48690eyjt3T1ajvjw== X-Received: by 2002:a17:90a:5208:: with SMTP id v8mr10250476pjh.29.1596311329344; Sat, 01 Aug 2020 12:48:49 -0700 (PDT) Received: from ast-mbp.dhcp.thefacebook.com ([2620:10d:c090:400::5:65b5]) by smtp.gmail.com with ESMTPSA id u66sm14834950pfb.191.2020.08.01.12.48.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 01 Aug 2020 12:48:48 -0700 (PDT) Date: Sat, 1 Aug 2020 12:48:46 -0700 From: Alexei Starovoitov To: Daniel Borkmann Cc: Christian Brauner , Christoph Hellwig , davem@davemloft.net, kuba@kernel.org, ast@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Rodrigo Madera Subject: Re: [PATCH net] net/bpfilter: initialize pos in __bpfilter_process_sockopt Message-ID: <20200801194846.dxmvg5fmg67nuhwy@ast-mbp.dhcp.thefacebook.com> References: <20200730160900.187157-1-hch@lst.de> <20200730161303.erzgrhqsgc77d4ny@wittgenstein> <03954b8f-0db7-427b-cfd6-7146da9b5466@iogearbox.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <03954b8f-0db7-427b-cfd6-7146da9b5466@iogearbox.net> Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Jul 31, 2020 at 02:07:42AM +0200, Daniel Borkmann wrote: > On 7/30/20 6:13 PM, Christian Brauner wrote: > > On Thu, Jul 30, 2020 at 06:09:00PM +0200, Christoph Hellwig wrote: > > > __bpfilter_process_sockopt never initialized the pos variable passed to > > > the pipe write. This has been mostly harmless in the past as pipes > > > ignore the offset, but the switch to kernel_write no verified the > > > > s/no/now/ > > > > > position, which can lead to a failure depending on the exact stack > > > initialization patter. Initialize the variable to zero to make > > > > s/patter/pattern/ > > > > > rw_verify_area happy. > > > > > > Fixes: 6955a76fbcd5 ("bpfilter: switch to kernel_write") > > > Reported-by: Christian Brauner > > > Reported-by: Rodrigo Madera > > > Signed-off-by: Christoph Hellwig > > > Tested-by: Rodrigo Madera > > > --- > > > > Thanks for tracking this down, Christoph! This fixes the logging issue > > for me. > > Tested-by: Christian Brauner > > Reviewed-by: Christian Brauner > > Applied to bpf & fixed up the typos in the commit msg, thanks everyone! Daniel, why is it necessary in bpf tree? I fixed it already in bpf-next in commit a4fa458950b4 ("bpfilter: Initialize pos variable") two weeks ago...