[PATCH 6.19 138/220] netfilter: nft_ct: drop pending enqueued packets on removal

Greg Kroah-Hartman
2026-03-23T13:56:26Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 36eae0956f659e48d5366d9b083d9417f3263ddc ]

Packets sitting in nfqueue might hold a reference to:

- templates that specify the conntrack zone, because a percpu area is
used and module removal is possible.
- conntrack timeout policies and helper, where object removal leave
a stale reference.

Since these objects can just go away, drop enqueued packets to avoid
stale reference to them.

If there is a need for finer grain removal, this logic can be revisited
to make selective packet drop upon dependencies.

Fixes: 7e0b2b57f01d ("netfilter: nft_ct: add ct timeout support")
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_ct.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 6f2ae7cad7310..db1bf69f87750 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -23,6 +23,7 @@
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_seqadj.h>
+#include "nf_internals.h"

struct nft_ct_helper_obj {
struct nf_conntrack_helper *helper4;
@@ -543,6 +544,7 @@ static void __nft_ct_set_destroy(const struct nft_ctx *ctx, struct nft_ct *priv)
#endif
#ifdef CONFIG_NF_CONNTRACK_ZONES
case NFT_CT_ZONE:
+ nf_queue_nf_hook_drop(ctx->net);
mutex_lock(&nft_ct_pcpu_mutex);
if (--nft_ct_pcpu_template_refcnt == 0)
nft_ct_tmpl_put_pcpu();
@@ -1016,6 +1018,7 @@ static void nft_ct_timeout_obj_destroy(const struct nft_ctx *ctx,
struct nft_ct_timeout_obj *priv = nft_obj_data(obj);
struct nf_ct_timeout *timeout = priv->timeout;

+ nf_queue_nf_hook_drop(ctx->net);
nf_ct_untimeout(ctx->net, timeout);
nf_ct_netns_put(ctx->net, ctx->family);
kfree(priv->timeout);
@@ -1148,6 +1151,7 @@ static void nft_ct_helper_obj_destroy(const struct nft_ctx *ctx,
{
struct nft_ct_helper_obj *priv = nft_obj_data(obj);

+ nf_queue_nf_hook_drop(ctx->net);
if (priv->helper4)
nf_conntrack_helper_put(priv->helper4);
if (priv->helper6)
--
2.51.0