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 1DAA21F8ADF for ; Wed, 8 Jan 2025 11:57:50 +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=1736337471; cv=none; b=uqHIELfynknLBtqjYT8KxyTJxa279wYcb7au61vAi90/1Z6juW4srLxqmBwIFRbVtJMRHMl4nbPWipu4saLWXSYRiHlKr1mVNDNLcR0GjHOe0zeRdlocChhsf3bHqopnYAYnoq/gSrOWW7BvtnZQoUaAiRKSXqvA2vCSX9/sv1A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736337471; c=relaxed/simple; bh=D5YzjvdjB3RXvjfxcHfXm82Xqr86PT3LxoQW3rjiYF4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Oe88nHYpdd60eh7KIVb7p9vA+ZPI14LWo5+CWHc+9jeBohgivHd8Gz/ZRBwQEFcDHwINnvKkPln54xZrsD6UFAIq0UhZ1k6BSMAO9BM93WU68AanMceiifZRKr1u26aX7DpckPE/62Zv8s+g9KNbYQQnihzlhwEFRkUZpVlhCkM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qLFWDOau; 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="qLFWDOau" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 19906C4CEDD; Wed, 8 Jan 2025 11:57:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736337470; bh=D5YzjvdjB3RXvjfxcHfXm82Xqr86PT3LxoQW3rjiYF4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=qLFWDOauRk18QCNyr6Vep/UqalniaGRyBx4toTRphH6HAZx2+66ujzgT4s7ZiNsE2 a7pcn6t7Zqxa0G73uK9ny1qp4SPD7Mip1+/vX2Gcsyc7iwupHu8Hcg47ZAIgq15noT lt7vyZkUJ23VntNiKtFnORTDwQYrH4uGqvsCl6uzZbsxVl/2Yoo1wbNiae0i15hVRN s64wy+HlBqHD4OfoSkr6fIh1L3i+h7mhfQzWkPXenkRIKxgl0l0lfkT/LD4ZNecdFO DqQWdFawj2+oPYlASFXt9blR+tkGttr9CIelb2/SPj5C5MEPPQcza+RlmRN2PCaTBO zphFKBsbt6p+Q== Message-ID: Date: Wed, 8 Jan 2025 12:57:48 +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 mptcp-net 0/9] net: sysctl: avoid using current->nsproxy Content-Language: en-GB To: Mat Martineau Cc: mptcp@lists.linux.dev References: <20250107-mptcp-sysfs-netns-v1-0-2fa7075d9970@kernel.org> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Mat, On 08/01/2025 02:49, Mat Martineau wrote: > On Tue, 7 Jan 2025, Matthieu Baerts (NGI0) wrote: > >> As pointed out by Al Viro and Eric Dumazet in [1], using the 'net' >> structure via 'current' is not recommended for different reasons: >> >> - Inconsistency: getting info from the reader's/writer's netns vs only >>  from the opener's netns. >> >> - current->nsproxy can be NULL in some cases, resulting in an 'Oops' >>  (null-ptr-deref), e.g. when the current task is exiting, as spotted by >>  syzbot [1] using acct(2). >> >> The 'net' or 'pernet' structure can be obtained from the table->data >> using container_of(). >> >> Note that table->data could also be used directly in more places, but >> that would increase the size of this fix to replace all accesses via >> 'net'. >> >> Patches 2-9 remove access of net via current->nsproxy in sysfs handlers >> in MPTCP, SCTP and RDS. There are multiple patches to ease the >> backports. >> >> Patch 1 is not directly linked to this, but it is a small fix for MPTCP >> available_schedulers sysctl knob to explicitly mark it as read-only. >> >> Please note that this series does not address Al's comment [2]. In SCTP, >> some sysctl knobs set other sysfs-exposed variables for the min/max: two >> processes could then write two linked values at the same time, resulting >> in new values being outside the new boundaries. > > > Thanks Matthieu, > > The mptcp patches (1-3) LGTM: > > Reviewed-by: Mat Martineau > > > The sctp and rds patches look fine as well. Thank you for this review! Patches are now in our tree (fixes for -net) with your RvB tag on the 3 first ones. I will upstream them later on today. New patches for t/upstream-net and t/upstream: - 968e9bb5a4cd: mptcp: sysctl: avail sched: remove write access - eda363130f80: mptcp: sysctl: sched: avoid using current->nsproxy - c838529f87ee: mptcp: sysctl: blackhole timeout: avoid using current->nsproxy - fb1a7a8fb16c: sctp: sysctl: cookie_hmac_alg: avoid using current->nsproxy - a18c9552dca0: sctp: sysctl: rto_min/max: avoid using current->nsproxy - 8408f9182e52: sctp: sysctl: auth_enable: avoid using current->nsproxy - c45cb99c9aa0: sctp: sysctl: udp_port: avoid using current->nsproxy - 3df3f684ee7e: sctp: sysctl: plpmtud_probe_interval: avoid using current->nsproxy - a77b912deb35: rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy - Results: bd3d4b1ab1bc..d66993cd4a59 (export-net) - Results: ebe8ebeee62e..f289bc80702c (export) Tests are now in progress: - export-net: https://github.com/multipath-tcp/mptcp_net-next/commit/6c101bff7e1613c0087472d2ee78c986e221435e/checks - export: https://github.com/multipath-tcp/mptcp_net-next/commit/0e96d0da96b041f087c5c0b46bc34978572ccffe/checks Cheers, Matt -- Sponsored by the NGI0 Core fund.