From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Stanislav Fomichev <sdf@google.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Mykola Lysenko <mykolal@fb.com>,
Shuah Khan <shuah@kernel.org>, Haowen Bai <baihaowen@meizu.com>,
bpf <bpf@vger.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Tom Rix <trix@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
clang-built-linux <llvm@lists.linux.dev>,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] bpf: Deprecate "data" member of bpf_lpm_trie_key
Date: Thu, 9 Feb 2023 12:50:28 -0800 [thread overview]
Message-ID: <CAADnVQKsB2n0=hShYpYnTr5yFYRt5MX2QMWo3V9SB9JrM6GhTg@mail.gmail.com> (raw)
In-Reply-To: <63e5521a.170a0220.297d7.3a80@mx.google.com>
On Thu, Feb 9, 2023 at 12:05 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Thu, Feb 09, 2023 at 11:52:10AM -0800, Andrii Nakryiko wrote:
> > Do we need to add a new type to UAPI at all here? We can make this new
> > struct internal to kernel code (e.g. struct bpf_lpm_trie_key_kern) and
> > point out that it should match the layout of struct bpf_lpm_trie_key.
> > User-space can decide whether to use bpf_lpm_trie_key as-is, or if
> > just to ensure their custom struct has the same layout (I see some
> > internal users at Meta do just this, just make sure that they have
> > __u32 prefixlen as first member).
>
> The uses outside the kernel seemed numerous enough to justify a new UAPI
> struct (samples, selftests, etc). It also paves a single way forward
> when the userspace projects start using modern compiler options (e.g.
> systemd is usually pretty quick to adopt new features).
I don't understand how the new uapi struct bpf_lpm_trie_key_u8 helps.
cilium progs and progs/map_ptr_kern.c
cannot do s/bpf_lpm_trie_key/bpf_lpm_trie_key_u8/.
They will fail to build, so they're stuck with bpf_lpm_trie_key.
Can we do just
struct bpf_lpm_trie_key_kern {
__u32 prefixlen;
__u8 data[];
};
and use it in the kernel?
What is the disadvantage?
next prev parent reply other threads:[~2023-02-09 20:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-09 19:23 [PATCH] bpf: Deprecate "data" member of bpf_lpm_trie_key Kees Cook
2023-02-09 19:52 ` Andrii Nakryiko
2023-02-09 20:05 ` Kees Cook
2023-02-09 20:50 ` Alexei Starovoitov [this message]
2023-02-09 21:12 ` Kees Cook
2023-02-09 22:01 ` Alexei Starovoitov
2023-02-11 17:55 ` Kees Cook
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