In the Linux kernel, the following vulnerability has been resolved:
netfilter: xtables: avoid NFPROTO_UNSPEC where needed
syzbot managed to call xt_cluster match via ebtables:
WARNING: CPU: 0 PID: 11 at net/netfilter/xtcluster.c:72 xtclustermt+0x196/0x780 [..] ebtdo_table+0x174b/0x2a40
Module registers to NFPROTO_UNSPEC, but it assumes ipv4/ipv6 packet processing. As this is only useful to restrict locally terminating TCP/UDP traffic, register this for ipv4 and ipv6 family only.
Pablo points out that this is a general issue, direct users of the set/getsockopt interface can call into targets/matches that were only intended for use with ip(6)tables.
Check all UNSPEC matches and targets for similar issues:
Most matches/targets are changed to register for NFPROTO_IPV4/IPV6, as they are provided for use by ip(6)tables.
The MARK target is also used by arptables, so register for NFPROTO_ARP too.
While at it, bail out if connbytes fails to enable the corresponding conntrack family.
This change passes the selftests in iptables.git.