From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Florent Revest <revest@chromium.org>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
KP Singh <kpsingh@chromium.org>,
open list <linux-kernel@vger.kernel.org>,
KP Singh <kpsingh@kernel.org>
Subject: Re: [PATCH bpf-next v6 4/5] selftests/bpf: Use vmlinux.h in socket_cookie_prog.c
Date: Wed, 27 Jan 2021 12:57:34 -0800 [thread overview]
Message-ID: <CAEf4BzbnQ6XfUAuBDeuO9qSNojHGKgXJZG3NtBp4MaAXjscr2Q@mail.gmail.com> (raw)
In-Reply-To: <20210126183559.1302406-4-revest@chromium.org>
On Tue, Jan 26, 2021 at 10:36 AM Florent Revest <revest@chromium.org> wrote:
>
> When migrating from the bpf.h's to the vmlinux.h's definition of struct
> bps_sock, an interesting LLVM behavior happened. LLVM started producing
> two fetches of ctx->sk in the sockops program this means that the
> verifier could not keep track of the NULL-check on ctx->sk. Therefore,
> we need to extract ctx->sk in a variable before checking and
> dereferencing it.
>
> Acked-by: KP Singh <kpsingh@kernel.org>
> Signed-off-by: Florent Revest <revest@chromium.org>
> ---
Acked-by: Andrii Nakryiko <andrii@kernel.org>
> .../testing/selftests/bpf/progs/socket_cookie_prog.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
> index 81e84be6f86d..fbd5eaf39720 100644
> --- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
> +++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
> @@ -1,12 +1,13 @@
> // SPDX-License-Identifier: GPL-2.0
> // Copyright (c) 2018 Facebook
>
> -#include <linux/bpf.h>
> -#include <sys/socket.h>
> +#include "vmlinux.h"
>
> #include <bpf/bpf_helpers.h>
> #include <bpf/bpf_endian.h>
>
> +#define AF_INET6 10
> +
> struct socket_cookie {
> __u64 cookie_key;
> __u32 cookie_value;
> @@ -41,7 +42,7 @@ int set_cookie(struct bpf_sock_addr *ctx)
> SEC("sockops")
> int update_cookie(struct bpf_sock_ops *ctx)
> {
> - struct bpf_sock *sk;
> + struct bpf_sock *sk = ctx->sk;
> struct socket_cookie *p;
>
> if (ctx->family != AF_INET6)
> @@ -50,10 +51,10 @@ int update_cookie(struct bpf_sock_ops *ctx)
> if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
> return 1;
>
> - if (!ctx->sk)
> + if (!sk)
> return 1;
>
> - p = bpf_sk_storage_get(&socket_cookies, ctx->sk, 0, 0);
> + p = bpf_sk_storage_get(&socket_cookies, sk, 0, 0);
> if (!p)
> return 1;
>
> --
> 2.30.0.280.ga3ce27912f-goog
>
next prev parent reply other threads:[~2021-01-27 20:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 18:35 [PATCH bpf-next v6 1/5] bpf: Be less specific about socket cookies guarantees Florent Revest
2021-01-26 18:35 ` [PATCH bpf-next v6 2/5] bpf: Expose bpf_get_socket_cookie to tracing programs Florent Revest
2021-01-27 21:01 ` Andrii Nakryiko
2021-01-30 11:35 ` Florent Revest
[not found] ` <4a8ceab1-6eef-9fda-0502-5a0550f53ddc@iogearbox.net>
[not found] ` <37730136-2c33-589c-a749-4221b60b9751@iogearbox.net>
2021-01-30 11:45 ` Florent Revest
2021-02-01 22:32 ` Daniel Borkmann
2021-02-01 22:37 ` Alexei Starovoitov
2021-02-10 11:10 ` Florent Revest
2021-01-26 18:35 ` [PATCH bpf-next v6 3/5] selftests/bpf: Integrate the socket_cookie test to test_progs Florent Revest
2021-01-27 20:58 ` Andrii Nakryiko
2021-01-26 18:35 ` [PATCH bpf-next v6 4/5] selftests/bpf: Use vmlinux.h in socket_cookie_prog.c Florent Revest
2021-01-27 20:57 ` Andrii Nakryiko [this message]
2021-01-26 18:35 ` [PATCH bpf-next v6 5/5] selftests/bpf: Add a selftest for the tracing bpf_get_socket_cookie Florent Revest
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