Am hitting an issue with this commit:
commit 0d7df906a0e78079a02108b06d32c3ef2238ad25
Author: Florian Westphal <f...@strlen.de>
Date: Tue Feb 27 19:42:37 2018 +0100
netfilter: x_tables: ensure last rule in base chain matches underflow/policy
This trips on my system:
[ 64.402790] ip6_tables: last base chain position 1136 doesn't match
underflow 1344 (hook 1)
More annoyingly, the return value means that ip6tables aren't initialized
so there's no firewall protection.
My iptables isn't syzkaller generated - it's mostly crufty vi-generated. ;)
Messages generated as I tried to build smaller tables to narrow down the
problem:
(not sure where it gets the numbers from, as I reduced it from 50 lines down to
3
and no real correlation to the tables I was trying to load - in particular the
numbers
went up once and remained unchanged once, even though between each try I was
whacking out another 5-10 lines...)
[ 64.402790] ip6_tables: last base chain position 1136 doesn't match
underflow 1344 (hook 1)
[ 1897.914828] ip6_tables: last base chain position 928 doesn't match underflow
1136 (hook 1)
[ 1954.032735] ip6_tables: last base chain position 720 doesn't match underflow
928 (hook 1)
[ 2021.813719] ip6_tables: last base chain position 920 doesn't match underflow
1128 (hook 1)
[ 2035.044103] ip6_tables: last base chain position 920 doesn't match underflow
1128 (hook 1)
[ 2060.594412] ip6_tables: last base chain position 616 doesn't match underflow
824 (hook 1)
I finally got /etc/sysconfig/ip6tables down to this:
# Generated by ip6tables-save v1.6.2 on Thu Mar 8 08:20:04 2018
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [208207395:46346275671]
[120166037:34218429901] -A INPUT -i lo+ -j ACCEPT
[129329499:129691207309] -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j
ACCEPT
[0:0] -A INPUT -j DROP
COMMIT
# Completed on Thu Mar 8 08:20:04 2018
About as minimal as it can get. :)
Any ideas?
