netdev - Re: [PATCH bpf-next v2 05/17] inet: Run SK_LOOKUP BPF program on socket lookup

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: <87wo5d2xht.fsf@cloudflare.com>
Date:   Fri, 15 May 2020 14:28:30 +0200
From:   Jakub Sitnicki <jakub@...udflare.com>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org, dccp@...r.kernel.org,
        kernel-team@...udflare.com, Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Gerrit Renker <gerrit@....abdn.ac.uk>,
        Jakub Kicinski <kuba@...nel.org>,
        Andrii Nakryiko <andrii.nakryiko@...il.com>,
        Martin KaFai Lau <kafai@...com>,
        Marek Majkowski <marek@...udflare.com>,
        Lorenz Bauer <lmb@...udflare.com>
Subject: Re: [PATCH bpf-next v2 05/17] inet: Run SK_LOOKUP BPF program on socket lookup

On Mon, May 11, 2020 at 10:44 PM CEST, Alexei Starovoitov wrote:
> On Mon, May 11, 2020 at 08:52:06PM +0200, Jakub Sitnicki wrote:
>> Run a BPF program before looking up a listening socket on the receive path.
>> Program selects a listening socket to yield as result of socket lookup by
>> calling bpf_sk_assign() helper and returning BPF_REDIRECT code.
>>
>> Alternatively, program can also fail the lookup by returning with BPF_DROP,
>> or let the lookup continue as usual with BPF_OK on return.
>>
>> This lets the user match packets with listening sockets freely at the last
>> possible point on the receive path, where we know that packets are destined
>> for local delivery after undergoing policing, filtering, and routing.
>>
>> With BPF code selecting the socket, directing packets destined to an IP
>> range or to a port range to a single socket becomes possible.
>>
>> Suggested-by: Marek Majkowski <marek@...udflare.com>
>> Reviewed-by: Lorenz Bauer <lmb@...udflare.com>
>> Signed-off-by: Jakub Sitnicki <jakub@...udflare.com>
>> ---

[...]

> Also please switch to bpf_link way of attaching. All system wide attachments
> should be visible and easily debuggable via 'bpftool link show'.
> Currently we're converting tc and xdp hooks to bpf_link. This new hook
> should have it from the beginning.

Just to clarify, I understood that bpf(BPF_PROG_ATTACH/DETACH) doesn't
have to be supported for new hooks.

Please correct me if I misunderstood.