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From: Song Liu <song@kernel.org>
To: Lorenz Bauer <lmb@cloudflare.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	kernel-team@cloudflare.com, Networking <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf v2 2/2] bpf: program: refuse non-O_RDWR flags in BPF_OBJ_GET
Date: Fri, 26 Mar 2021 13:13:46 -0700	[thread overview]
Message-ID: <CAPhsuW7E4bhEGcboKQ5O=1o0iVNPLpJB1nrAgxweiZqGhZm-JQ@mail.gmail.com> (raw)
In-Reply-To: <20210326160501.46234-2-lmb@cloudflare.com>

On Fri, Mar 26, 2021 at 9:07 AM Lorenz Bauer <lmb@cloudflare.com> wrote:
>
> As for bpf_link, refuse creating a non-O_RDWR fd. Since program fds
> currently don't allow modifications this is a precaution, not a
> straight up bug fix.
>
> Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
> ---
>  kernel/bpf/inode.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
> index dc56237d6960..d2de2abec35b 100644
> --- a/kernel/bpf/inode.c
> +++ b/kernel/bpf/inode.c
> @@ -543,7 +543,7 @@ int bpf_obj_get_user(const char __user *pathname, int flags)
>                 return PTR_ERR(raw);

For both patches, shall we do the check before bpf_obj_do_get(), which is a few
lines above?

Thanks,
Song

>
>         if (type == BPF_TYPE_PROG)
> -               ret = bpf_prog_new_fd(raw);
> +               ret = (f_flags != O_RDWR) ? -EINVAL : bpf_prog_new_fd(raw);
>         else if (type == BPF_TYPE_MAP)
>                 ret = bpf_map_new_fd(raw, f_flags);
>         else if (type == BPF_TYPE_LINK)
> --
> 2.27.0
>

  reply	other threads:[~2021-03-26 20:14 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26 16:05 [PATCH bpf v2 1/2] bpf: link: refuse non-O_RDWR flags in BPF_OBJ_GET Lorenz Bauer
2021-03-26 16:05 ` [PATCH bpf v2 2/2] bpf: program: " Lorenz Bauer
2021-03-26 20:13   ` Song Liu [this message]
2021-03-28  4:51     ` Andrii Nakryiko
2021-03-29  8:19     ` Lorenz Bauer
2021-03-28  4:49 ` [PATCH bpf v2 1/2] bpf: link: " Andrii Nakryiko
2021-03-31 14:04 ` Lorenz Bauer
2021-04-01 18:04   ` Alexei Starovoitov
2021-04-01 21:44   ` Alexei Starovoitov

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