From fdf6491193e411087ae77bcbc6468e3e1cff99ed Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 20 Feb 2023 17:24:00 +0100 Subject: netfilter: ctnetlink: make event listener tracking global pernet tracking doesn't work correctly because other netns might have set NETLINK_LISTEN_ALL_NSID on its event socket. In this case its expected that events originating in other net namespaces are also received. Making pernet-tracking work while also honoring NETLINK_LISTEN_ALL_NSID requires much more intrusive changes both in netlink and nfnetlink, f.e. adding a 'setsockopt' callback that lets nfnetlink know that the event socket entered (or left) ALL_NSID mode. Move to global tracking instead: if there is an event socket anywhere on the system, all net namespaces which have conntrack enabled and use autobind mode will allocate the ecache extension. netlink_has_listeners() returns false only if the given group has no subscribers in any net namespace, the 'net' argument passed to nfnetlink_has_listeners is only used to derive the protocol (nfnetlink), it has no other effect. For proper NETLINK_LISTEN_ALL_NSID-aware pernet tracking of event listeners a new netlink_has_net_listeners() is also needed. Fixes: 90d1daa45849 ("netfilter: conntrack: add nf_conntrack_events autodetect mode") Reported-by: Bryce Kahle Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/netfilter.h') diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index d8817d381c14..bef8db9d6c08 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -488,4 +488,9 @@ extern const struct nfnl_ct_hook __rcu *nfnl_ct_hook; */ DECLARE_PER_CPU(bool, nf_skb_duplicated); +/** + * Contains bitmask of ctnetlink event subscribers, if any. + * Can't be pernet due to NETLINK_LISTEN_ALL_NSID setsockopt flag. + */ +extern u8 nf_ctnetlink_has_listener; #endif /*__LINUX_NETFILTER_H*/ -- cgit