From: David Laight <David.Laight@ACULAB.COM>
To: 'Jakub Kicinski' <kuba@kernel.org>, Martin KaFai Lau <kafai@fb.com>
Cc: Stanislav Fomichev <sdf@google.com>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
David Miller <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
"kernel-team@fb.com" <kernel-team@fb.com>,
Paolo Abeni <pabeni@redhat.com>
Subject: RE: [PATCH bpf-next 02/14] bpf: net: Avoid sock_setsockopt() taking sk lock when called from bpf
Date: Fri, 29 Jul 2022 10:04:29 +0000 [thread overview]
Message-ID: <732a8006394f49d58c586156f3f81281@AcuMS.aculab.com> (raw)
In-Reply-To: <20220728095629.6109f78c@kernel.org>
From: Jakub Kicinski
> Sent: 28 July 2022 17:56
>
> On Thu, 28 Jul 2022 09:31:04 -0700 Martin KaFai Lau wrote:
> > If I understand the concern correctly, it may not be straight forward to
> > grip the reason behind the testings at in_bpf() [ the in_task() and
> > the current->bpf_ctx test ] ? Yes, it is a valid point.
> >
> > The optval.is_bpf bit can be directly traced back to the bpf_setsockopt
> > helper and should be easier to reason about.
>
> I think we're saying the opposite thing. in_bpf() the context checking
> function is fine. There is a clear parallel to in_task() and combined
> with the capability check it should be pretty obvious what the code
> is intending to achieve.
>
> sockptr_t::in_bpf which randomly implies that the lock is already held
> will be hard to understand for anyone not intimately familiar with the
> BPF code. Naming that bit is_locked seems much clearer.
>
> Which is what I believe Stan was proposing.
Or make sk_setsockopt() be called after the integer value
has been read and with the lock held.
That saves any (horrid) conditional locking.
Also sockptr_t should probably have been a structure with separate
user and kernel address fields.
Putting the length in there would (probably) save code.
There then might be scope for pre-copying short user buffers
into a kernel buffer while still allowing the requests that
ignore the length copy directly from a user buffer.
David
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Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2022-07-29 10:04 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-27 6:08 [PATCH bpf-next 00/14] bpf: net: Remove duplicated codes from bpf_setsockopt() Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 01/14] net: Change sock_setsockopt from taking sock ptr to sk ptr Martin KaFai Lau
2022-07-27 8:11 ` David Laight
2022-07-27 20:42 ` Martin KaFai Lau
2022-07-27 8:16 ` Eric Dumazet
2022-07-27 18:50 ` Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 02/14] bpf: net: Avoid sock_setsockopt() taking sk lock when called from bpf Martin KaFai Lau
2022-07-27 8:36 ` David Laight
2022-07-27 20:05 ` Martin KaFai Lau
2022-07-27 16:47 ` sdf
2022-07-27 18:37 ` Martin KaFai Lau
2022-07-27 20:39 ` Stanislav Fomichev
2022-07-27 21:21 ` Martin KaFai Lau
2022-07-27 21:38 ` Stanislav Fomichev
2022-07-28 0:45 ` Martin KaFai Lau
2022-07-28 1:49 ` Jakub Kicinski
2022-07-28 16:31 ` Martin KaFai Lau
2022-07-28 16:56 ` Jakub Kicinski
2022-07-28 17:20 ` Martin KaFai Lau
2022-07-28 17:40 ` Jakub Kicinski
2022-07-29 10:04 ` David Laight [this message]
2022-07-29 19:06 ` Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 03/14] bpf: net: Consider optval.is_bpf before capable check in sock_setsockopt() Martin KaFai Lau
2022-07-27 16:54 ` sdf
2022-07-27 18:47 ` Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 04/14] bpf: net: Avoid do_tcp_setsockopt() taking sk lock when called from bpf Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 05/14] bpf: net: Avoid do_ip_setsockopt() " Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 06/14] bpf: net: Avoid do_ipv6_setsockopt() " Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 07/14] bpf: Embed kernel CONFIG check into the if statement in bpf_setsockopt Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 08/14] bpf: Change bpf_setsockopt(SOL_SOCKET) to reuse sock_setsockopt() Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 09/14] bpf: Refactor bpf specific tcp optnames to a new function Martin KaFai Lau
2022-07-27 6:09 ` [PATCH bpf-next 10/14] bpf: Change bpf_setsockopt(SOL_TCP) to reuse do_tcp_setsockopt() Martin KaFai Lau
2022-07-27 6:10 ` [PATCH bpf-next 11/14] bpf: Change bpf_setsockopt(SOL_IP) to reuse do_ip_setsockopt() Martin KaFai Lau
2022-07-27 6:10 ` [PATCH bpf-next 12/14] bpf: Change bpf_setsockopt(SOL_IPV6) to reuse do_ipv6_setsockopt() Martin KaFai Lau
2022-07-27 6:10 ` [PATCH bpf-next 13/14] bpf: Add a few optnames to bpf_setsockopt Martin KaFai Lau
2022-07-27 6:10 ` [PATCH bpf-next 14/14] selftests/bpf: bpf_setsockopt tests Martin KaFai Lau
2022-07-27 17:14 ` [PATCH bpf-next 00/14] bpf: net: Remove duplicated codes from bpf_setsockopt() Jakub Kicinski
2022-07-27 20:42 ` Martin KaFai Lau
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