[Bug 214419] ipfw coredump when try to add rule with table of IPv6 addresses

[wo0x]

Hi there,

   I just subscribed to this list due to the subjected bug--and I am quite
happy to find this trouble has yet been noted by others:

# fwcmd=/sbin/ipfw
# ${fwcmd} -f table dnssrv flush
# ${fwcmd}    table dnssrv create type addr
# ${fwcmd}    table dnssrv add 2a02:e00:fffd:139::9
added: 2a02:e00:fffd:139::9/128 0
# ${fwcmd}    table dnssrv add 2001:41D0:A:0028::1
added: 2001:41d0:a:28::1/128 0
# ${fwcmd}    table dnssrv add 2001:4860:4860::8844
added: 2001:4860:4860::8844/128 0
# ${fwcmd} add 20020 allow ip6 from any to "table(dnssrv)" out via gif0
setup keep-state
Segmentation fault (core dumped)
# uname -v
FreeBSD 11.0-STABLE #0 r308635: Mon Nov 14 08:55:15 UTC 2016
root at tunnel.example.vnet:/usr/obj/usr/src/sys/CUSTOM

When doing "ipfw list" all rules are with numbers lower to 20020 are listed
correctly. Then again SegFault is notified and processing of further rules
is interrupted, more precisely: The mandatory "65535 deny ip from any to
any" is also missing.

This is from within a VNET jail using a cloned "gif  interface. If
connection is relevant: The jails "external" interface has the same MAC
address like the host system. Involved is a netgraph utilizing ng_etf, that
filters ethertypes ipv4 (0x0800) and arp (0x0806) to the affected jails
ng_eiface.

If I can help with any input, please let me know. I am just lacking
knowledge to debug or analyze dumps.

Best"
Benjamin