When not running for a specific family only (via -4/-6 flags), xtables-monitor potentially sees events/traces for all families. To correctly parse rules when printing for NEWRULE, DELRULE or TRACE messages, nft_handle has to be reinitialized for the rule's family. It is not sufficient to reset nft_handle::ops: Some expression parsers rely upon nft_handle::family to be properly set, too (cf. references to 'ctx->h->family in nft-ruleparse.c). Adjusting the 'afinfo' pointer provided by libxtables is even more crucial, as e.g. do_parse() in xshared.c relies upon it for the proper optstring. This is actually a day-1 bug in xtables-monitor which surfaced due to commit 9075c3aa983d9 ("nft: Increase rule parser strictness"). Therefore make this fix the commit it is following-up. Fixes: ca69b0290dc50 ("xtables-monitor: Fix ip6tables rule printing") Signed-off-by: Phil Sutter <phil@xxxxxx> --- iptables/xtables-monitor.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/iptables/xtables-monitor.c b/iptables/xtables-monitor.c index cf2729d87968b..cf92355f76f8a 100644 --- a/iptables/xtables-monitor.c +++ b/iptables/xtables-monitor.c @@ -92,7 +92,9 @@ static int rule_cb(const struct nlmsghdr *nlh, void *data) if (arg->nfproto && arg->nfproto != family) goto err_free; + xtables_set_nfproto(family); arg->h->ops = nft_family_ops_lookup(family); + arg->h->family = family; if (arg->is_event) printf(" EVENT: "); -- 2.43.0