From: Carl Lei <xecycle@gmail.com>
To: netfilter@vger.kernel.org
Subject: Re: nft tproxy failed to redirect on one system
Date: Wed, 22 Nov 2023 10:59:58 +0800 [thread overview]
Message-ID: <20231122105958.76a2cb30@xcws1> (raw)
In-Reply-To: <327D57E822A265D5+20230822181631.528b64c2@xcws1>
On Tue, 22 Aug 2023 18:16:31 +0800
Carl Lei <me@xecycle.info> wrote:
> On Tue, 22 Aug 2023 12:05:01 +0200
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
>
> > On Mon, Aug 21, 2023 at 03:48:07PM +0800, Carl Lei wrote:
> > > Btw: sent to wrong address, re-sent to list...
> > >
> > > On Fri, 11 Aug 2023 12:00:43 +0800
> > > Carl Lei <me@xecycle.info> wrote:
> > >
> > > > Sorry for being incomplete, but I added nftrace before these
> > > > rules and saw packets went through the same chain of rules,
> > > > first hitting tproxy in mangle, then meta mark 42 counter
> > > > accept in input-new-isolated. But on one system it works for
> > > > local programs AND network-received packets, on another system
> > > > it works only for local programs. On the bad system the
> > > > packets instead gets directed to whatever program originally
> > > > listening on the original port, or rejected; e.g. I have an
> > > > nginx listening on 0.0.0.0:80 but no programs on 443, then curl
> > > > http in a vm connected to vbr0 goes to my nginx, and curl https
> > > > gets rejected. I expect them to go to that program listening
> > > > on 1081.
> > >
> > > Looked closer at the trace, I found that on the bad system, when
> > > the packet goes back to input rules, its trace id changed; on the
> > > good system it does not change. Perhaps this explains it, but I
> > > don't know why it was changed?
> >
> > Could you provide more detailed information on your setup? You refer
> > to a system where this works fine and another where this does not,
> > but you do not specify kernel and userspace versions?
>
> Sorry I forgot that in my first email, indeed I replied to myself
> several times and already provided versions, but I did not realize I
> sent to a wrong address. My used versions are (copying from my
> previous mails):
>
> "they are both running Arch Linux, the good system running kernel
> 6.4.8-arch1-1, the bad system I tried both 6.4.4 and 6.4.9; nftables
> version both 1:1.0.7-2; the proxy program on 1081 is also identical,
> running identical config."
>
> > Some simple script with 'ip netns' as a reproducer might also help
> > that might help people jump in a provide feedback.
>
> I will try ASAP to make a reproducer.
Sorry for the delay, I finally figured out what is going on.
When I do `modprobe br_netfilter`, which automatically sets sysctl
net/bridge/bridge-nf-call-iptables=1, the rule breaks --- the packet
would change trace id when it comes back to INPUT chains. After I set
that sysctl to 0, the rule works again.
And yes, the packet is coming from a container, having a veth connected
to a bridge on the host.
next prev parent reply other threads:[~2023-11-22 3:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230811120043.0c3c6302@xcws1>
2023-08-21 7:48 ` nft tproxy failed to redirect on one system Carl Lei
2023-08-22 10:05 ` Pablo Neira Ayuso
2023-08-22 10:16 ` Carl Lei
2023-11-22 2:59 ` Carl Lei [this message]
2023-08-11 4:00 Carl Lei
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231122105958.76a2cb30@xcws1 \
--to=xecycle@gmail.com \
--cc=netfilter@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).