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 A8EB8CA5A; Sat, 21 Dec 2024 10:28:30 +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=1734776910; cv=none; b=Zd/hiES75pzMXxL6Db3PMwbnEzOkHGBZVMg4TVFpZDrsx5EQHTzgWsypI5Csej+DTHVYm3P3DHa5zwEtN3CwBe9jhvgPw1/HXJrJJUaUv6QQRpz9ztgsb1sPdxmsv/B1xwwYCo6FXCx75bNYlmaJHnZqj3Et/vFHPhFL283DAOQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734776910; c=relaxed/simple; bh=F8qyLk2tQa0JK3a0b5tK09o53tJ+d/qyRpNct4qmXKc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Lyh7CZ+OsVfETbIr3OQMvopUNpB09q4/fYQul8I4/hzfcovsCkFMcbXb65KFhkM7uMzmK7vOVBRRZ51MJEU65dLohoGKkhilGawJactqi8rJ2qABBINVTv778OK3YFQVMPGA9K6QgberYdpqLR+2M+1GOtJ9Q75w/rdYDhh/keg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iyLdsT/n; 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="iyLdsT/n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E52BC4CECE; Sat, 21 Dec 2024 10:28:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734776910; bh=F8qyLk2tQa0JK3a0b5tK09o53tJ+d/qyRpNct4qmXKc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=iyLdsT/nJrKFR2MLsSwIx9L76rSuuFPuR6fMP9dPZq/A1D/KZRdIS/Wn3TYdCURnR l8lWD9JEVFQif/1NPHwDT/Og/Uc6kM6zV942nE4m/Fm0f35js8twbgbeCpFyak0NB3 CTpwtCR5su71BwQqwdGeOG37PY7eKMfywfsWr6raPne7Ac+IXVATKTb9lr+8VRYvqJ 7t/hnBrSdse3ZoUlgm0MFuaBCduoM9W6pAMPll6so04wbG4K5fyTtQgonKEstOrY3y co5H2+3veYjslLNWH1VLzgy60ywWIqTXJ8HGsHqSCDVoqWXmN/y8is8G/13+FY3HRy R8NV2h+GbfYTQ== Message-ID: <047cb3ef-f0c0-43e4-82e9-dc0073c8b953@kernel.org> Date: Sat, 21 Dec 2024 11:28:26 +0100 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 net] mptcp: fix TCP options overflow. Content-Language: en-GB To: Paolo Abeni , netdev@vger.kernel.org Cc: Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Simon Horman , mptcp@lists.linux.dev, stable@vger.kernel.org References: <025d9df8cde3c9a557befc47e9bc08fbbe3476e5.1734771049.git.pabeni@redhat.com> 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: <025d9df8cde3c9a557befc47e9bc08fbbe3476e5.1734771049.git.pabeni@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Paolo, On 21/12/2024 09:51, Paolo Abeni wrote: > Syzbot reported the following splat: (...) > Eric noted a probable shinfo->nr_frags corruption, which indeed > occurs. > > The root cause is a buggy MPTCP option len computation in some > circumstances: the ADD_ADDR option should be mutually exclusive > with DSS since the blamed commit. > > Still, mptcp_established_options_add_addr() tries to set the > relevant info in mptcp_out_options, if the remaining space is > large enough even when DSS is present. > > Since the ADD_ADDR infos and the DSS share the same union > fields, adding first corrupts the latter. In the worst-case > scenario, such corruption increases the DSS binary layout, > exceeding the computed length and possibly overwriting the > skb shared info. > > Address the issue by enforcing mutual exclusion in > mptcp_established_options_add_addr(), too. Thank you for the investigation and the fix, it looks good to me: Reviewed-by: Matthieu Baerts (NGI0) > Reported-by: syzbot+38a095a81f30d82884c1@syzkaller.appspotmail.com If you don't mind, can you please add these two tags when applying the patches to help to track the backports? Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/538 Cc: stable@vger.kernel.org > Fixes: 1bff1e43a30e ("mptcp: optimize out option generation") > Signed-off-by: Paolo Abeni Cheers, Matt -- Sponsored by the NGI0 Core fund.