linux-kernel - Re: [PATCH 4.19 13/99] netfilter: nf_conncount: fix argument order to find_next

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Date:   Mon, 22 Apr 2019 21:26:56 +0200
From:   Andreas Hartmann <andihartmann@...enet.de>
To:     Florian Westphal <fw@...len.de>
Cc:     Pablo Neira Ayuso <pablo@...filter.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4.19 13/99] netfilter: nf_conncount: fix argument order to
 find_next_bit

On 22.04.19 at 20:57 Florian Westphal wrote:
> Andreas Hartmann <andihartmann@...19freenet.de> wrote:
>>> Could you at least tell us how you're using nf_conncount (nf/iptables
>>> rules)?
>>
>> # Generated by iptables-save v1.6.2 on Mon Apr 22 20:19:30 2019
>> *filter
>> :INPUT DROP [0:0]
>> :FORWARD ACCEPT [0:0]
>> :OUTPUT DROP [4423:248703]
>> -A INPUT -s 127.0.0.1/32 -d 239.255.255.250/32 -i lo -p udp -j ACCEPT
>> -A INPUT -p tcp -m tcp --dport 113 -j REJECT --reject-with icmp-port-unreachable
>> -A INPUT -d 255.255.255.255/32 -p udp -j ACCEPT
>> -A INPUT -d 224.0.0.1/32 -j ACCEPT
>> -A INPUT -s 127.0.0.1/32 -d 127.0.0.2/32 -i lo -j ACCEPT
>> -A INPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -i lo -j ACCEPT
>> -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
>> -A INPUT -s 192.168.22.0/24 -j ACCEPT
>> -A INPUT -j LOG --log-prefix "In Input gesperrt: "
>> -A INPUT -s 169.254.2.1/32 -d 169.254.2.2/32 -i br1 -p tcp -m tcp --sport 80 -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -d 224.0.0.22/32 -o lo -p igmp -j ACCEPT
>> -A OUTPUT -d 192.168.6.173/32 -o br1 -p tcp -m tcp --dport 80 -j ACCEPT
>> -A OUTPUT -s 169.254.2.2/32 -d 239.255.255.250/32 -o br1 -p udp -j DROP
>> -A OUTPUT -s 192.168.22.6/32 -d 224.0.0.251/32 -o br1 -p udp -j ACCEPT
>> -A OUTPUT -s 127.0.0.1/32 -d 239.255.255.250/32 -o lo -p udp -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -d 255.255.255.255/32 -o br1 -p udp -m udp --dport 1900 -j ACCEPT
>> -A OUTPUT -s 127.0.0.1/32 -d 127.255.255.255/32 -o br1 -p udp -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -d 239.0.0.250/32 -o br1 -p igmp -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -d 239.255.255.250/32 -o br1 -p igmp -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -d 239.255.255.250/32 -o br1 -p udp -m udp --dport 1900 -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -d 239.1.1.1/32 -o br1 -p udp -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -d 239.1.1.1/32 -o br1 -p igmp -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -d 224.0.0.251/32 -o br1 -p igmp -j ACCEPT
>> -A OUTPUT -s 192.168.22.6/32 -p tcp -m tcp --dport 1935 -j ACCEPT
>> -A OUTPUT -s 192.168.22.0/24 -d 192.168.3.0/24 -j ACCEPT
>> -A OUTPUT -s 127.0.0.1/32 -d 127.0.0.2/32 -o lo -j ACCEPT
>> -A OUTPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -o lo -j ACCEPT
>> -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
>> -A OUTPUT -s 192.168.22.0/24 -d 192.168.22.0/24 -j ACCEPT
>> -A OUTPUT -j LOG --log-prefix "In Output gesperrt: "
>> -A OUTPUT -s 169.254.2.2/32 -d 169.254.2.1/32 -o br1 -p tcp -m tcp --dport 80 -j ACCEPT
>> COMMIT
> 
> I don't see connlimit match is in use.
> 
> Could you post output of
> 
> lsmod | grep nf_conncount
> 
> and
> 
> grep CONNCOUNT ~/your_kernel_conf

True - it's not in use (it's not even configured) at all. I'm surprised that it seems to fix the problem anyway.
Ok - I'm testing few weeks more. If it comes up again: this has been a false positive.
If I can't see it any more - I wouldn't know what to do any further at the moment.

Regarding git bisect, the only other possible remaining changes would be at the moment

tty: Don't hold ldisc lock in tty_reopen() if ldisc present                     Dmitry Safonov
tty: Simplify tty->count math in tty_reopen()                                   Dmitry Safonov
tty: Hold tty_ldisc_lock() during tty_reopen()                                  Dmitry Safonov
tty/ldsem: Wake up readers after timed out down_write()                         Dmitry Safonov

But I don't know how this change could break video streaming using serviio ... .


Thanks
Andreas