This is a note to let you know that I've just added the patch titled
netfilter: ctnetlink: make event listener tracking global
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-ctnetlink-make-event-listener-tracking-glo.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 15e3c5a951052b86d3aa166bb35e4e83ec8b2ba8
Author: Florian Westphal <fw@xxxxxxxxx>
Date: Mon Feb 20 17:24:00 2023 +0100
netfilter: ctnetlink: make event listener tracking global
[ Upstream commit fdf6491193e411087ae77bcbc6468e3e1cff99ed ]
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 <bryce.kahle@xxxxxxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index d8817d381c14b..bef8db9d6c085 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*/
diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h
index e1290c159184a..1f463b3957c78 100644
--- a/include/net/netns/conntrack.h
+++ b/include/net/netns/conntrack.h
@@ -95,7 +95,6 @@ struct nf_ip_net {
struct netns_ct {
#ifdef CONFIG_NF_CONNTRACK_EVENTS
- u8 ctnetlink_has_listener;
bool ecache_dwork_pending;
#endif
u8 sysctl_log_invalid; /* Log invalid packets */
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 5a6705a0e4ecf..6e80f0f6149ea 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -669,6 +669,9 @@ const struct nf_ct_hook __rcu *nf_ct_hook __read_mostly;
EXPORT_SYMBOL_GPL(nf_ct_hook);
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
+u8 nf_ctnetlink_has_listener;
+EXPORT_SYMBOL_GPL(nf_ctnetlink_has_listener);
+
const struct nf_nat_hook __rcu *nf_nat_hook __read_mostly;
EXPORT_SYMBOL_GPL(nf_nat_hook);
diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c
index 8698b34246460..69948e1d6974e 100644
--- a/net/netfilter/nf_conntrack_ecache.c
+++ b/net/netfilter/nf_conntrack_ecache.c
@@ -309,7 +309,7 @@ bool nf_ct_ecache_ext_add(struct nf_conn *ct, u16 ctmask, u16 expmask, gfp_t gfp
break;
return true;
case 2: /* autodetect: no event listener, don't allocate extension. */
- if (!READ_ONCE(net->ct.ctnetlink_has_listener))
+ if (!READ_ONCE(nf_ctnetlink_has_listener))
return true;
fallthrough;
case 1:
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 6d18fb3468683..81c7737c803a6 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -29,6 +29,7 @@
#include <net/netlink.h>
#include <net/netns/generic.h>
+#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
MODULE_LICENSE("GPL");
@@ -685,12 +686,12 @@ static void nfnetlink_bind_event(struct net *net, unsigned int group)
group_bit = (1 << group);
spin_lock(&nfnl_grp_active_lock);
- v = READ_ONCE(net->ct.ctnetlink_has_listener);
+ v = READ_ONCE(nf_ctnetlink_has_listener);
if ((v & group_bit) == 0) {
v |= group_bit;
/* read concurrently without nfnl_grp_active_lock held. */
- WRITE_ONCE(net->ct.ctnetlink_has_listener, v);
+ WRITE_ONCE(nf_ctnetlink_has_listener, v);
}
spin_unlock(&nfnl_grp_active_lock);
@@ -744,12 +745,12 @@ static void nfnetlink_unbind(struct net *net, int group)
spin_lock(&nfnl_grp_active_lock);
if (!nfnetlink_has_listeners(net, group)) {
- u8 v = READ_ONCE(net->ct.ctnetlink_has_listener);
+ u8 v = READ_ONCE(nf_ctnetlink_has_listener);
v &= ~group_bit;
/* read concurrently without nfnl_grp_active_lock held. */
- WRITE_ONCE(net->ct.ctnetlink_has_listener, v);
+ WRITE_ONCE(nf_ctnetlink_has_listener, v);
}
spin_unlock(&nfnl_grp_active_lock);
#endif
