netdev - Re: [Patch bpf v2] skmsg: check sk_rcvbuf limit before queuing to ingress

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: <877diarpsz.fsf@cloudflare.com>
Date:   Thu, 01 Jul 2021 17:56:12 +0200
From:   Jakub Sitnicki <jakub@...udflare.com>
To:     Cong Wang <xiyou.wangcong@...il.com>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        Cong Wang <cong.wang@...edance.com>,
        Jiang Wang <jiang.wang@...edance.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        John Fastabend <john.fastabend@...il.com>,
        Lorenz Bauer <lmb@...udflare.com>
Subject: Re: [Patch bpf v2] skmsg: check sk_rcvbuf limit before queuing to
 ingress_skb

On Thu, Jul 01, 2021 at 08:16 AM CEST, Cong Wang wrote:
> From: Cong Wang <cong.wang@...edance.com>
>
> Jiang observed OOM frequently when testing our AF_UNIX/UDP
> proxy. This is due to the fact that we do not actually limit
> the socket memory before queueing skb to ingress_skb. We
> charge the skb memory later when handling the psock backlog,
> but it is not limited either.
>
> This patch adds checks for sk->sk_rcvbuf right before queuing
> to ingress_skb and drops packets if this limit exceeds. This
> is very similar to UDP receive path. Ideally we should set the
> skb owner before this check too, but it is hard to make TCP
> happy about sk_forward_alloc.
>
> Reported-by: Jiang Wang <jiang.wang@...edance.com>
> Cc: Daniel Borkmann <daniel@...earbox.net>
> Cc: John Fastabend <john.fastabend@...il.com>
> Cc: Lorenz Bauer <lmb@...udflare.com>
> Cc: Jakub Sitnicki <jakub@...udflare.com>
> Signed-off-by: Cong Wang <cong.wang@...edance.com>
> ---

Acked-by: Jakub Sitnicki <jakub@...udflare.com>

By saying that it is hard to make TCP happy about sk_forward_alloc, I'm
guessing you're referring to problems described in 144748eb0c44 ("bpf,
sockmap: Fix incorrect fwd_alloc accounting") [1]?

Thanks for the fix.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=144748eb0c445091466c9b741ebd0bfcc5914f3d

[...]