From: Lorenz Bauer <lmb@cloudflare.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: kernel-team <kernel-team@cloudflare.com>,
Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf v2 1/2] bpf: link: refuse non-O_RDWR flags in BPF_OBJ_GET
Date: Wed, 31 Mar 2021 15:04:13 +0100 [thread overview]
Message-ID: <CACAyw9_FHepkTzdFkiGUFV6F8u7zaZYOeH+bUjWxcBNBNeBYBg@mail.gmail.com> (raw)
In-Reply-To: <20210326160501.46234-1-lmb@cloudflare.com>
On Fri, 26 Mar 2021 at 16:05, Lorenz Bauer <lmb@cloudflare.com> wrote:
>
> Invoking BPF_OBJ_GET on a pinned bpf_link checks the path access
> permissions based on file_flags, but the returned fd ignores flags.
> This means that any user can acquire a "read-write" fd for a pinned
> link with mode 0664 by invoking BPF_OBJ_GET with BPF_F_RDONLY in
> file_flags. The fd can be used to invoke BPF_LINK_DETACH, etc.
>
> Fix this by refusing non-O_RDWR flags in BPF_OBJ_GET. This works
> because OBJ_GET by default returns a read write mapping and libbpf
> doesn't expose a way to override this behaviour for programs
> and links.
Hi Alexei and Daniel,
I think these two patches might have fallen through the cracks, could
you take a look? I'm not sure what the etiquette is around bumping a
set, so please let me know if you'd prefer me to send the patches with
acks included or something like that.
Best
--
Lorenz Bauer | Systems Engineer
6th Floor, County Hall/The Riverside Building, SE1 7PB, UK
www.cloudflare.com
next prev parent reply other threads:[~2021-03-31 14:05 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
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 [this message]
2021-04-01 18:04 ` Alexei Starovoitov
2021-04-01 21:44 ` Alexei Starovoitov
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