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 ECF8A28D8D1 for ; Thu, 22 May 2025 15:01:42 +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=1747926103; cv=none; b=le0OnoLu2chVvAKV6i3CXVDBjQFMh21sdRfgNYt7uLxW361qFTijEOeKT4lWhCmg54mK7rKsou8O0kSyGzp9F1Ohbor+D7Fzw32wnOA1lLUzDgZ5+iX0qyWSDMsaJ7mv2OGnk/d316qnI9vGZquYXRhx0cvZhYcEv+NjWzGewPw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747926103; c=relaxed/simple; bh=vc0vgLYAQE9jzGVdH+RIFukLzTCKNXnC6T+AWqR0grc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WJK5+UBUWEUWUFRA3l6JZIMKZvGgSUHFG/k952CSyy1EvBRWTB2Re0BXFTsHmv3/yHS/GiNiCLwSYZpE+osYhIaD2iNE1zhX9t2bHuEzybPmRH2COuMnOb9G4qpVQoVJxNoIFoHmhaeAPe8dz6pDumOJhuKZzN750CXIiw6+iv0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eIgxv6Mj; 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="eIgxv6Mj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E71FC4CEE4; Thu, 22 May 2025 15:01:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747926102; bh=vc0vgLYAQE9jzGVdH+RIFukLzTCKNXnC6T+AWqR0grc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=eIgxv6Mj51PvX1o5rPBmd4IAanffhW9zrpWpowZIbdXKqTPeLJ+7hugiWxxSqIBps ir8p8M0ytbp6rXks3fjA4NRkTns3fY3+6fCGP3S+kiWYmiKQIsH1WDobqwbbJMmnV0 p6ClvJ6OFzHXh1dJAV+qgLubf5nhWdKuk8gUbJIoGvC2yaLc/+93WO5UoMHMb3F04M /MMJ6weO9NV1fEK+Wr7qa132N6ybtw5FsOYsp5uopJ1fgvTBDGGCLG6SUEhpCOuLkG 6M0HgwmQtda4tBebexGN1cZPmdszeu9+wWhiSZaGcHTwJDOtAdz1tsZR/Ym4B0oNRy Z14VOPQPgWnDA== Message-ID: Date: Thu, 22 May 2025 17:01:37 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH v1 net-next 2/6] socket: Rename sock_create_kern() to __sock_create_kern(). Content-Language: en-GB, fr-BE To: Kuniyuki Iwashima , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn Cc: Simon Horman , Kuniyuki Iwashima , netdev@vger.kernel.org References: <20250517035120.55560-1-kuniyu@amazon.com> <20250517035120.55560-3-kuniyu@amazon.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: <20250517035120.55560-3-kuniyu@amazon.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Kuniyuki, On 17/05/2025 05:50, Kuniyuki Iwashima wrote: > sock_create_kern() is a catchy name and often chosen by non-networking > developers to create kernel sockets. But due to its poor documentation, > it has caused a bunch of netns use-after-free: > > * commit ef7134c7fc48 ("smb: client: Fix use-after-free of network > namespace.") > * commit b013b817f32f ("nvme-tcp: fix use-after-free of netns by > kernel TCP socket.") > .. and more in NFS, SMC, MPTCP, RDS > > Some non-networking maintainers mentioned that the socket API should > be more robust to prevent this type of issues. [0] > > The current sock_create_kern() doesn't hold a reference to the netns, > which allows the netns to be removed while the socket is still around. > This is useful when the socket is used as the backend for a networking > device. > > But, this is rather a special case, where netdev folks should use a > dedicated API, and we should provide sock_create_kern() as the standard > API for general in-kernel use cases. > > In fact, we did so before commit 26abe14379f8 ("net: Modify sk_alloc > to not reference count the netns of kernel sockets."), > > sock_create_kern(&init_net, ..., &sock) > sk_change_net(sock->sk, net); > > but that implicit API change ended up causing a lot of problems. > > Let's rename sock_create_kern() to __sock_create_kern() as a special > API and add a fat documentation. > > The next patch will add sock_create_kern() that holds netns refcnt. Thank you for clarifying this! (...) > diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c > index d39e7c178460..a7467497de0f 100644 > --- a/net/mptcp/pm_kernel.c > +++ b/net/mptcp/pm_kernel.c > @@ -637,8 +637,8 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk, > int backlog = 1024; > int err; > > - err = sock_create_kern(sock_net(sk), entry->addr.family, > - SOCK_STREAM, IPPROTO_MPTCP, &entry->lsk); > + err = __sock_create_kern(sock_net(sk), entry->addr.family, > + SOCK_STREAM, IPPROTO_MPTCP, &entry->lsk); > if (err) > return err; > > diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c > index 15613d691bfe..602e689e991f 100644 > --- a/net/mptcp/subflow.c > +++ b/net/mptcp/subflow.c > @@ -1757,7 +1757,7 @@ int mptcp_subflow_create_socket(struct sock *sk, unsigned short family, > if (unlikely(!sk->sk_socket)) > return -EINVAL; > > - err = sock_create_kern(net, family, SOCK_STREAM, IPPROTO_TCP, &sf); > + err = __sock_create_kern(net, family, SOCK_STREAM, IPPROTO_TCP, &sf); > if (err) > return err; > > @@ -1948,7 +1948,7 @@ static int subflow_ulp_init(struct sock *sk) > int err = 0; > > /* disallow attaching ULP to a socket unless it has been > - * created with sock_create_kern() > + * created with __sock_create_kern() > */ > if (!sk->sk_kern_sock) { > err = -EOPNOTSUPP; For the changes in MPTCP: Acked-by: Matthieu Baerts (NGI0) # net/mptcp (...) Cheers, Matt -- Sponsored by the NGI0 Core fund.