From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 9990147ACC5 for ; Thu, 20 Aug 2026 16:03:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787241841; cv=none; b=QjIykbSJqJrMtXPHiOSY7kpunU7mnU4bMkw+GA0baSuiaW1ALdloQkz415Js3GtxhnqWgVfBYcy+MdAkIQz9QqUXRKLsjxIja656spn8Ao5e9G8zcrhEYMIqbc4HUdkk0z/Oea83gq9xfHi2YFlV6zz3l1iR8BFZabKZaA1qY/I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787241841; c=relaxed/simple; bh=gQhSMy9VM9ZBiuqB3pME/3XeXjsNEKPI7hNykgtF6gc=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=gko3beAPY3wM3CUfKTkYu/rUGDOEKyd754NdWwFHrfk7SoSHB2Va3MTMm02EMiBB7PCNaDuPuiNx0OBZtakP7PFnovWjEx3M08GvjBsw1/IPw7D/WEwr6aa0ctpu0a/ChRRNjUpccSOEqDU4NLC3lxCybUmWmQReuRERzZjJ3Pg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Fmc5jzT2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Fmc5jzT2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF37C1F000E9; Thu, 20 Aug 2026 16:03:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787241839; bh=Juiu+jZnExXFp5Y3thLZE3HHicJVl/CLH4Pg4WYN5X8=; h=Date:Subject:To:References:From:In-Reply-To; b=Fmc5jzT2K2oUIZTijbqE4rLDM4ZtpPp3stlOZ8lwwOqa4/zvfkm7FsTn6AHcxFvsE DXwF1Td8+wHp5ioihuLgNn4yXlcUjtT5WdZ2ST/3ywRhK1WQDiYSx7V8XwI+Uf84MG Hm9kBE5nobX/iArohdMlwvshbQa/7E1rR1c7xWqob7tnst7c/sdL4gxOmIOFQZeIRI EbOkuEaXsFGaYM0K3YvI8qYQF7ttRAi7n2/JYGRwjN1L+ouEq4WKhF1i2HKPW2Jde3 hBr7CeTT7rqFOez3oc5eUEU+d9x1BCmVRSEJtLFpXGlpwAnvRCzhbnfJqEgo90KUUP 8XKksjkkQMSxA== Message-ID: Date: Thu, 20 Aug 2026 18:03:57 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH mptcp-net] mptcp: options: fix uninit-value in mptcp_write_data_fin Content-Language: fr To: Geliang Tang , MPTCP Linux References: <20260814-mptcp-dfin-csum-v1-1-08d0b9b86bb7@kernel.org> <0680b4cbbcb963684af9101936825fa09b71a335.camel@kernel.org> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Geliang, On 19/08/2026 11:09, Geliang Tang wrote: > Hi Matt, > > On Fri, 2026-08-14 at 23:38 +0200, Matthieu Baerts (NGI0) wrote: >> When sending a DATA_FIN without data, and because the DATA_FIN >> occupies >> 1 octet of the connection-level sequence space [1], it is then >> required >> to add a DSS mapping with specific values. >> >> If the checksum has been negotiated, it also needs to be computed, >> and >> included in the outgoing packet, and thus the initial csum data needs >> to >> be reset to 0 as well. This is no longer the case since commit >> cfcceb7a39fc ("tcp: shrink per-packet memset in >> __tcp_transmit_skb()"), >> because the whole ext_copy structure is no longer zeroed by default. >> >> This seems to be the only case where use_map is changed and set >> afterwards, so initialising the csum field only in this case, along >> with >> other fields for this specific case. > > Initially, I was wondering if we could skip calling mptcp_make_csum() > for data_fin in mptcp_write_options(), similar to how we skip it for > the infinite mapping: > > /* data_len == 0 is reserved for the infinite mapping, > * the checksum will also be set to 0. > */ > put_len_csum(mpext->data_len, > (mpext->data_len ? mptcp_make_csum(mpext) : 0), > ptr); > > But I realized that your modification is more straightforward. > >> >> Fixes: cfcceb7a39fc ("tcp: shrink per-packet memset in >> __tcp_transmit_skb()") >> Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.3.3 [1] >> Link: >> https://sashiko.dev/#/patchset/20260812-net-next-mptcp-misc-feat-7-3-v1-0-1905a818f6cb%40kernel.org?part=2 >> Signed-off-by: Matthieu Baerts (NGI0) > > Looks good to me! > > Reviewed-by: Geliang Tang Thank you for the review! New patches for t/upstream-net and t/upstream: - fbdc41264992: mptcp: options: fix uninit-value in mptcp_write_data_fin - Results: e9b9aadd7dfb..d251bdc7d65e (export-net) - Results: 8cefef708ced..77661003be12 (export) Tests are now in progress: - export-net: https://github.com/multipath-tcp/mptcp_net-next/commit/439ace86ec3085a503e16283cf2719876d9a9d7e/checks - export: https://github.com/multipath-tcp/mptcp_net-next/commit/7c1c363f2cd4fb1dbd7edb83dc2d57313289d200/checks Cheers, Matt -- Sponsored by the NGI0 Core fund.