From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 217D51D3566; Thu, 5 Dec 2024 09:24:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733390666; cv=none; b=O8OdXc77MpWBH2kLRuqnBO4H3pm5br7XM8jKrC61QQ+KbV8mWuc/0uI6smZRpeHm6m567qBRY6rLaOoBmpdH13ASj/9N8ELUqc/sr/Txuh+ARYQ7RciwA32JKJdqkLocNNIDL3zvXkLIWUEDYeLIysfSK1KeyDikcFrXA+7Pd94= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733390666; c=relaxed/simple; bh=cxFYSQQ5LcnRKyXdrDH1BoaRM9MtIMnb4DyaV45f1Bc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=K/M8Q/AN4yaJGL2UAuou5tc2apxPWEpvpAj41Eb1BRT8mnTiyx4GTjR8M3r71eK3Yx4PuvB/2f9U8rS/cq9LBEuudwyKHsWQAyP7mo03rHpYTLShp4Ffn3CBgwTbS9aMUb7L92UUFrC19WMmq2vUOaysiKQlJotEswbhgl4MIjk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FzD77ljE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FzD77ljE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA971C4CED6; Thu, 5 Dec 2024 09:24:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733390665; bh=cxFYSQQ5LcnRKyXdrDH1BoaRM9MtIMnb4DyaV45f1Bc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=FzD77ljENiZ+ljuA89DGZ4YEL0purKsI+Ut5BV2BeTJoj1TdLCMjQ1BnBHEILfPO2 rOtuNGQaSqSz/+nZEcQFHb0uYJ2vxBksDCxN9kHAbfpjhxePSQaLqwvfPcAn5n7WOu MWqsudJR6pmiF97rZIwOpdRvXiKBhM7kc7sOP+wbZP3Ecg4+N+MtklOXNll27VOBVF 7ONCEioOfv8Wy3Eqjt4HSV9jSuOOCa8ECOrBNwLCXbUCifV9l2f65fRGoXAmnQCcHL XIWdVGNYqe17nJqu4RyybxB3sR8Op3aWh7JodcXbe1HDOa28M/bRqslrS+0F7mKy7M /9bqEBrngQT/w== Message-ID: <0f07b584-1013-4932-b155-cc0883ca7061@kernel.org> Date: Thu, 5 Dec 2024 10:24:20 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net-next] tcp: Check space before adding MPTCP options Content-Language: en-GB To: Mo Yuanhao Cc: martineau@kernel.org, geliang@kernel.org, davem@davemloft.net, dsahern@kernel.org, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, mptcp@lists.linux.dev, stable@vger.kernel.org, Eric Dumazet References: <20241204085801.11563-1-moyuanhao3676@163.com> <80b6603d-ed52-43b7-a434-0253e5de784a@kernel.org> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi MoYuanhao, On 05/12/2024 08:54, Eric Dumazet wrote: > On Thu, Dec 5, 2024 at 8:31 AM Mo Yuanhao wrote: >> >> 在 2024/12/4 19:01, Matthieu Baerts 写道: >>> Hi MoYuanhao, >>> >>> +Cc MPTCP mailing list. >>> >>> (Please cc the MPTCP list next time) >>> >>> On 04/12/2024 09:58, MoYuanhao wrote: >>>> Ensure enough space before adding MPTCP options in tcp_syn_options() >>>> Added a check to verify sufficient remaining space >>>> before inserting MPTCP options in SYN packets. >>>> This prevents issues when space is insufficient. >>> >>> Thank you for this patch. I'm surprised we all missed this check, but >>> yes it is missing. >>> >>> As mentioned by Eric in his previous email, please add a 'Fixes' tag. >>> For bug-fixes, you should also Cc stable and target 'net', not 'net-next': >>> >>> Fixes: cec37a6e41aa ("mptcp: Handle MP_CAPABLE options for outgoing >>> connections") >>> Cc: stable@vger.kernel.org >>> >>> >>> Regarding the code, it looks OK to me, as we did exactly that with >>> mptcp_synack_options(). In mptcp_established_options(), we pass >>> 'remaining' because many MPTCP options can be set, but not here. So I >>> guess that's fine to keep the code like that, especially for the 'net' tree. >>> >>> >>> Also, and linked to Eric's email, did you have an issue with that, or is >>> it to prevent issues in the future? >>> >>> >>> One last thing, please don’t repost your patches within one 24h period, see: >>> >>> https://docs.kernel.org/process/maintainer-netdev.html >>> >>> >>> Because the code is OK to me, and the same patch has already been sent >>> twice to the netdev ML within a few hours, I'm going to apply this patch >>> in our MPTCP tree with the suggested modifications. Later on, we will >>> send it for inclusion in the net tree. >>> >>> pw-bot: awaiting-upstream >>> >>> (Not sure this pw-bot instruction will work as no net/mptcp/* files have >>> been modified) >>> >>> Cheers, >>> Matt >> Hi Matt, >> >> Thank you for your feedback! >> >> I have made the suggested updates to the patch (version 2): >> >> I’ve added the Fixes tag and Cc'd the stable@vger.kernel.org list. >> The target branch has been adjusted to net as per your suggestion. >> I will make sure to Cc the MPTCP list in future submissions. >> >> Regarding your question, this patch was created to prevent potential >> issues related to insufficient space for MPTCP options in the future. I >> didn't encounter a specific issue, but it seemed like a necessary >> safeguard to ensure robustness when handling SYN packets with MPTCP options. >> >> Additionally, I have made further optimizations to the patch, which are >> included in the attached version. I believe it would be more elegant to >> introduce a new function, mptcp_set_option(), similar to >> mptcp_set_option_cond(), to handle MPTCP options. >> >> This is my first time replying to a message in a Linux mailing list, so >> if there are any formatting issues or mistakes, please point them out >> and I will make sure to correct them in future submissions. >> >> Thanks again for your review and suggestions. Looking forward to seeing >> the patch applied to the MPTCP tree and later inclusion in the net tree. > > We usually do not refactor for a patch targeting a net tree. Indeed, I agree with Eric. Even if the code looks good, more lines have been modified, maybe more risks, but also harder to backport to stable. Also, I already applied your previous patches with the modifications I suggested -- the code is the same as in v1, only the commit message has been modified -- in the MPTCP tree: New patches for t/upstream-net and t/upstream: - 06dcf123ebe0: tcp: check space before adding MPTCP SYN options - Results: 4fdf39fbfdb4..05c0ade28862 (export-net) - Results: 0de5663a2d56..993a44eee93f (export) Tests have been running too: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/12158569520 Is this patch not OK for you? https://github.com/multipath-tcp/mptcp_net-next/commit/06dcf123ebe0 Cheers, Matt -- Sponsored by the NGI0 Core fund.