netdev - RE: [PATCH v2 bpf-next 1/5] bpf: add support for forced LINK

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5f24a70aa2fa7_54fa2b1d9fe285b4cf@john-XPS-13-9370.notmuch>
Date:   Fri, 31 Jul 2020 16:19:38 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     Andrii Nakryiko <andriin@...com>, bpf@...r.kernel.org,
        netdev@...r.kernel.org, ast@...com, daniel@...earbox.net
Cc:     andrii.nakryiko@...il.com, kernel-team@...com,
        Andrii Nakryiko <andriin@...com>,
        Song Liu <songliubraving@...com>
Subject: RE: [PATCH v2 bpf-next 1/5] bpf: add support for forced LINK_DETACH
 command

Andrii Nakryiko wrote:
> Add LINK_DETACH command to force-detach bpf_link without destroying it. It has
> the same behavior as auto-detaching of bpf_link due to cgroup dying for
> bpf_cgroup_link or net_device being destroyed for bpf_xdp_link. In such case,
> bpf_link is still a valid kernel object, but is defuncts and doesn't hold BPF
> program attached to corresponding BPF hook. This functionality allows users
> with enough access rights to manually force-detach attached bpf_link without
> killing respective owner process.
> 
> This patch implements LINK_DETACH for cgroup, xdp, and netns links, mostly
> re-using existing link release handling code.
> 
> Acked-by: Song Liu <songliubraving@...com>
> Signed-off-by: Andrii Nakryiko <andriin@...com>
> ---

Looks necessary otherwise we have no way, as far as I read it, to delete
an XDP program and go back the no prog state after link_{create|update}.

Acked-by: John Fastabend <john.fastabend@...il.com>