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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DCB0AC4332F for ; Thu, 10 Mar 2022 22:42:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344366AbiCJWnm (ORCPT ); Thu, 10 Mar 2022 17:43:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344401AbiCJWne (ORCPT ); Thu, 10 Mar 2022 17:43:34 -0500 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 636C6B51 for ; Thu, 10 Mar 2022 14:42:31 -0800 (PST) Received: by mail-pl1-x62c.google.com with SMTP id e2so6148060pls.10 for ; Thu, 10 Mar 2022 14:42:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=message-id:date:mime-version:user-agent:content-language:to:cc :references:from:subject:in-reply-to:content-transfer-encoding; bh=H0dJecyPS2t445Yyuaocacfsz4kMpFTNDFKZg5I5Xqo=; b=i2+4Hhkq0ffVuy/voAgJ7Oie2KiFixt/XYRgrrvr6dmSS6Qob5Wmq9eVqbssVG/Prz NZKOO3RZDuV1X5NCn3/n69tAPp9lX1Q8rfhM9oczaPrXHNiLC7k/Aqdn/AuwHiAldis2 G2Gz0IpLA0/WkI4mr0CL1pkAmvljkK0MqjH7oZuZ0AeS0C2qPAhHZGoaVoB3Km3j5tE5 1PZkCUi8Sjgri2Mi5KBmQGRAzr0wfrySJPF6OjoYKqatacXrXCJsZ0FohWDwgJKVE04B b7XCJdSrDWHSVxF2XGnY6kwky7gCnRwqeHHuDWF3JvOd1hc/hnbHvT62GCX8HpFGNF4G T0jg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent :content-language:to:cc:references:from:subject:in-reply-to :content-transfer-encoding; bh=H0dJecyPS2t445Yyuaocacfsz4kMpFTNDFKZg5I5Xqo=; b=tdvF5k2Ol8ZGaIGI9bflmQ5HER4JzHqLYR86w6P94APjRXZuv0R/iLUmXZUVZBvq35 o9ytuNcWVdb8KQG0pZglCpZUGtWaxViKkVfcVe14LrhNMcJNpU81VW8WYp++ra//vtOM W4xgzDhO4t9jzplYNOcclQRFFlJHDWJYnkGJizSoQQ/EmLA3lI1N4eq+vR/xRgdDa22a erwMtTYckb2qdh5KIfArMOs5WAuyFfPwv0P9vTmyMT8xL0ByDJ+quQIqLhLbSvbUIVF1 +CDdi/x0p1MvcTs/MUvwnbQ8I8OGOWiamM3b90DrHZbxT4OI018bc5oiY1o3knRhnKBY aRHA== X-Gm-Message-State: AOAM530A9gIDVR+x4xxwFXn+7QF8KPbOAQV+udH5xqqiBAh/vRX7LIiZ ip43th33u+6XWZB+VM+U6iX+tw== X-Google-Smtp-Source: ABdhPJz+HM8Z5oVHOCVhGxstjdd7fA+IbJhbFxh8NNun6SGE5r59isngyOt7OckA9+Vcvc9xTcThVg== X-Received: by 2002:a17:902:cccc:b0:14e:e89c:c669 with SMTP id z12-20020a170902cccc00b0014ee89cc669mr7408737ple.58.1646952150727; Thu, 10 Mar 2022 14:42:30 -0800 (PST) Received: from [192.168.254.17] ([50.39.160.154]) by smtp.gmail.com with ESMTPSA id y10-20020a63b50a000000b0038088a28ec0sm6504255pge.22.2022.03.10.14.42.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Mar 2022 14:42:30 -0800 (PST) Message-ID: <62a9b061-1cf5-dff1-c062-a3961de92dca@linaro.org> Date: Thu, 10 Mar 2022 14:42:29 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Content-Language: en-US To: Jakub Kicinski Cc: davem@davemloft.net, Willem de Bruijn , Hideaki YOSHIFUJI , David Ahern , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, syzbot+e223cf47ec8ae183f2a0@syzkaller.appspotmail.com References: <20220310221328.877987-1-tadeusz.struk@linaro.org> <20220310143011.00c21f53@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: Tadeusz Struk Subject: Re: [PATCH v2] net: ipv6: fix skb_over_panic in __ip6_append_data In-Reply-To: <20220310143011.00c21f53@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 3/10/22 14:30, Jakub Kicinski wrote: >> + >> + /* >> + * Check if there is still room for payload >> + */ > TBH I think the check is self-explanatory. Not worth a banner comment, > for sure. Ok > >> + if (fragheaderlen >= mtu) { >> + err = -EMSGSIZE; >> + kfree_skb(skb); >> + goto error; >> + } > Not sure if Willem prefers this placement, but seems like we can lift > this check out of the loop, as soon as fragheaderlen and mtu are known. > He said to check it before the skb_put() and so I did. The fragheaderlen is known early, but mtu can be updated inside the loop by ip6_append_data_mtu() so I'm not sure we can do the check before that. -- Thanks, Tadeusz