From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794337843; b=zFkxdRijq94cQk5VbBBQTdU3D5jhLX4TSJrIWS8DXYEB/bksfJzZjNCdOBdmRxlTzJez 1pnnsyGIMLDtYhLtsufUFRlO/ZEScPc9fhOYIquZUBeogikgb7d7XzkM0kGcNAb3h9AXh fLtmrSuNiJ4GZgx1CjsG5owEzYPQcoPPYRtJYv7Hio44aEnbM5LvdDZKvtqZi/MqnIHXq kPBridsZOuivcNB9aKnwIIDUIEg8EJezuW3aJiV/T8X54E1qfIxue3HoiUMw3jnGqVXUP 3znZMLZwL+FvAXWUef+EKBOKxj9S/2X0iUp0tA2SL4r87NKmaQrH6CnPpQtfMI2S4Xw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794337843; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:Content-Language:To:Cc:References:From:Autocrypt:Organization: In-Reply-To:Content-Type:Content-Transfer-Encoding; bh=rX5bGHGHbQdz2HJQU94iTFz4MzHCw+66W5HX4woLxJU=; b=HEtMXaTXTyVmh3+Erxe5WUn9L0vIAMfwYTIHTTm/Em0CkZsvIBXBi0QlX9vF29ifX0kX /gIqnCpx7YjV3umT+4KwijJWLDQQ8zCh8l6RRDaTcYagvZC6YezOcgpfGBR65skkRcIwe qUUMDqLPvAbjK1NxqhLCxdWsscFzdB4Mz/A5E19qiw4ypspUPA9CGP9FrgFJ+05I1t7L1 3TD6ob541tfRa5qNCSoYVdLvXjtKuA36yFCqkTUN8TcCBHWGcrw4Ir0f6UJZNl1CUlXiI UT5ei6pR5Ou2ksEIXnYVb+qL6BDgTGAc6NvZZDqyEmgciT7ecMHWoOJg069l1HdfZnA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ISpOO8YU; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F940606A320; Tue, 10 Nov 2026 19:10:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ISpOO8YU Received: by smtp.kernel.org (Postfix) with ESMTPSA id B889E1F0089F; Tue, 10 Nov 2026 19:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794337843; bh=rX5bGHGHbQdz2HJQU94iTFz4MzHCw+66W5HX4woLxJU=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ISpOO8YUBuHYjih4u0J5MiALoBs+CBneFpjwVn33ld/A/qtonhrUKQ1RAQBdZJ0Bd UjkHxRsNoBD85cugGJKFEVKEvHj2rrfgrqNqmDeY59Dd2EtpDH5aQGCJeppLDtlhQ0 ChC1KQlXWKWQnKroWllU9JMv5fpToz6YeZ5lRV/i5JDRkUF9iRmbsztp8cPysj7irZ wE7GhOQ9B21hdo1+6bW97u4mhOegjtW3bLgc99E3JNjxGxk3bzkF8UdaMeG2gmW62v Ds5U887ir9Tb6dwuwEuJfXefE7NbezaX8vKAOcR17j6GBJROsWQ4ZHGc6LKdhpRF8d 4GOIJqZsbgT0A== Message-ID: Date: Tue, 10 Nov 2026 20:10:37 +0100 X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net] mptcp: reject DATA_ACKs against a reversed send interval Content-Language: fr To: Eric Dumazet Cc: "David S . Miller" , Jakub Kicinski , Paolo Abeni , Mat Martineau , Geliang Tang , Simon Horman , Kuniyuki Iwashima , netdev@vger.kernel.org, Kyle Zeng , MPTCP Linux References: <20261104130747.1045741-1-edumazet@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: <20261104130747.1045741-1-edumazet@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Eric, (+cc MPTCP list) On 04/11/2026 14:07, Eric Dumazet wrote: > From: Kyle Zeng > > ack_update_msk() samples snd_nxt before taking the data lock, but reads > snd_una after taking it. Concurrent transmission and ACK processing can > therefore leave the sampled upper bound behind snd_una. Active-open > completion also exposes a reversed interval when it initializes snd_una > to IDSN + 1 while the socket-owned state synchronization is deferred. > > A peer-supplied 64-bit Data ACK half a sequence space away can pass both > wraparound comparisons against such an interval. The resulting snd_una > can make __mptcp_retrans() inflate a fragment's already_sent field. Later > ACKs can then underflow data_len and cause out-of-bounds page fragments > to be passed to TCP. > > Read snd_nxt after acquiring the data lock and reject reversed intervals > before checking the received Data ACK. This keeps the interval shorter > than half the sequence space, so the existing upper-bound check cannot > accept an advance beyond snd_nxt. Preserve the existing handling of old > ACKs and keep the transmit fields under their existing socket locking. Sorry, I missed this patch (the MPTCP CI didn't get it). It looks good to me: Reviewed-by: Matthieu Baerts (NGI0) While at it: Cc: stable@vger.kernel.org @Net Maintainers: this patch can be applied to the net tree directly, thank you! (Or did I miss my review window?) Cheers, Matt -- Sponsored by the NGI0 Core fund.