[PATCH net 0/3] Netfilter fixes for net

[PATCH net 0/3] Netfilter fixes for net

[Florian Westphal]

The following patchset contains Netfilter fixes for *net*:

1) I managed to add a null dereference crash in nft_set_pipapo
   in the current development cycle, was not caught by CI
   because the avx2 implementation is fine, but selftest
   splats when run on non-avx2 host.

2) Fix the ipvs estimater kthread affinity, was incorrect
   since 6.14. From Frederic Weisbecker.

3) nf_tables should not allow to add a device to a flowtable
   or netdev chain more than once -- reject this.
   From Pablo Neira Ayuso.  This has been broken for long time,
   blamed commit dates from v5.8.

Please, pull these changes from:
The following changes since commit d7e82594a45c5cb270940ac469846e8026c7db0f:

  selftests: tls: test TCP stealing data from under the TLS socket (2025-08-12 18:59:06 -0700)

are available in the Git repository at:

  https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git tags/nf-25-08-13

for you to fetch changes up to cf5fb87fcdaaaafec55dcc0dc5a9e15ead343973:

  netfilter: nf_tables: reject duplicate device on updates (2025-08-13 08:34:55 +0200)

----------------------------------------------------------------
netfilter pull request nf-25-08-13

----------------------------------------------------------------
Florian Westphal (1):
      netfilter: nft_set_pipapo: fix null deref for empty set

Frederic Weisbecker (1):
      ipvs: Fix estimator kthreads preferred affinity

Pablo Neira Ayuso (1):
      netfilter: nf_tables: reject duplicate device on updates

 include/net/ip_vs.h            | 13 +++++++++++++
 kernel/kthread.c               |  1 +
 net/netfilter/ipvs/ip_vs_est.c |  3 ++-
 net/netfilter/nf_tables_api.c  | 30 ++++++++++++++++++++++++++++++
 net/netfilter/nft_set_pipapo.c |  5 ++---
 5 files changed, 48 insertions(+), 4 deletions(-)
-- 
2.49.1

[PATCH net 1/3] netfilter: nft_set_pipapo: fix null deref for empty set

[Florian Westphal]

Blamed commit broke the check for a null scratch map:
  -  if (unlikely(!m || !*raw_cpu_ptr(m->scratch)))
  +  if (unlikely(!raw_cpu_ptr(m->scratch)))

This should have been "if (!*raw_ ...)".
Use the pattern of the avx2 version which is more readable.

This can only be reproduced if avx2 support isn't available.

Fixes: d8d871a35ca9 ("netfilter: nft_set_pipapo: merge pipapo_get/lookup")
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nft_set_pipapo.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
index 1a19649c2851..9a10251228fd 100644
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -426,10 +426,9 @@ static struct nft_pipapo_elem *pipapo_get(const struct nft_pipapo_match *m,
 
 	local_bh_disable();
 
-	if (unlikely(!raw_cpu_ptr(m->scratch)))
-		goto out;
-
 	scratch = *raw_cpu_ptr(m->scratch);
+	if (unlikely(!scratch))
+		goto out;
 
 	map_index = scratch->map_index;
 
-- 
2.49.1

[PATCH net 2/3] ipvs: Fix estimator kthreads preferred affinity

[Florian Westphal]

From: Frederic Weisbecker <frederic@kernel.org>

The estimator kthreads' affinity are defined by sysctl overwritten
preferences and applied through a plain call to the scheduler's affinity
API.

However since the introduction of managed kthreads preferred affinity,
such a practice shortcuts the kthreads core code which eventually
overwrites the target to the default unbound affinity.

Fix this with using the appropriate kthread's API.

Fixes: d1a89197589c ("kthread: Default affine kthread to its preferred NUMA node")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/net/ip_vs.h            | 13 +++++++++++++
 kernel/kthread.c               |  1 +
 net/netfilter/ipvs/ip_vs_est.c |  3 ++-
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index ff406ef4fd4a..29a36709e7f3 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -1163,6 +1163,14 @@ static inline const struct cpumask *sysctl_est_cpulist(struct netns_ipvs *ipvs)
 		return housekeeping_cpumask(HK_TYPE_KTHREAD);
 }
 
+static inline const struct cpumask *sysctl_est_preferred_cpulist(struct netns_ipvs *ipvs)
+{
+	if (ipvs->est_cpulist_valid)
+		return ipvs->sysctl_est_cpulist;
+	else
+		return NULL;
+}
+
 static inline int sysctl_est_nice(struct netns_ipvs *ipvs)
 {
 	return ipvs->sysctl_est_nice;
@@ -1270,6 +1278,11 @@ static inline const struct cpumask *sysctl_est_cpulist(struct netns_ipvs *ipvs)
 	return housekeeping_cpumask(HK_TYPE_KTHREAD);
 }
 
+static inline const struct cpumask *sysctl_est_preferred_cpulist(struct netns_ipvs *ipvs)
+{
+	return NULL;
+}
+
 static inline int sysctl_est_nice(struct netns_ipvs *ipvs)
 {
 	return IPVS_EST_NICE;
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 0e98b228a8ef..31b072e8d427 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -893,6 +893,7 @@ int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask)
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(kthread_affine_preferred);
 
 /*
  * Re-affine kthreads according to their preferences
diff --git a/net/netfilter/ipvs/ip_vs_est.c b/net/netfilter/ipvs/ip_vs_est.c
index f821ad2e19b3..15049b826732 100644
--- a/net/netfilter/ipvs/ip_vs_est.c
+++ b/net/netfilter/ipvs/ip_vs_est.c
@@ -265,7 +265,8 @@ int ip_vs_est_kthread_start(struct netns_ipvs *ipvs,
 	}
 
 	set_user_nice(kd->task, sysctl_est_nice(ipvs));
-	set_cpus_allowed_ptr(kd->task, sysctl_est_cpulist(ipvs));
+	if (sysctl_est_preferred_cpulist(ipvs))
+		kthread_affine_preferred(kd->task, sysctl_est_preferred_cpulist(ipvs));
 
 	pr_info("starting estimator thread %d...\n", kd->id);
 	wake_up_process(kd->task);
-- 
2.49.1

[PATCH net 3/3] netfilter: nf_tables: reject duplicate device on updates

[Florian Westphal]

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

A chain/flowtable update with duplicated devices in the same batch is
possible. Unfortunately, netdev event path only removes the first
device that is found, leaving unregistered the hook of the duplicated
device.

Check if a duplicated device exists in the transaction batch, bail out
with EEXIST in such case.

WARNING is hit when unregistering the hook:

 [49042.221275] WARNING: CPU: 4 PID: 8425 at net/netfilter/core.c:340 nf_hook_entry_head+0xaa/0x150
 [49042.221375] CPU: 4 UID: 0 PID: 8425 Comm: nft Tainted: G S                  6.16.0+ #170 PREEMPT(full)
 [...]
 [49042.221382] RIP: 0010:nf_hook_entry_head+0xaa/0x150

Fixes: 78d9f48f7f44 ("netfilter: nf_tables: add devices to existing flowtable")
Fixes: b9703ed44ffb ("netfilter: nf_tables: support for adding new devices to an existing netdev chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nf_tables_api.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 13d0ed9d1895..58c5425d61c2 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2803,6 +2803,7 @@ static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,
 	struct nft_chain *chain = ctx->chain;
 	struct nft_chain_hook hook = {};
 	struct nft_stats __percpu *stats = NULL;
+	struct nftables_pernet *nft_net;
 	struct nft_hook *h, *next;
 	struct nf_hook_ops *ops;
 	struct nft_trans *trans;
@@ -2845,6 +2846,20 @@ static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,
 				if (nft_hook_list_find(&basechain->hook_list, h)) {
 					list_del(&h->list);
 					nft_netdev_hook_free(h);
+					continue;
+				}
+
+				nft_net = nft_pernet(ctx->net);
+				list_for_each_entry(trans, &nft_net->commit_list, list) {
+					if (trans->msg_type != NFT_MSG_NEWCHAIN ||
+					    trans->table != ctx->table ||
+					    !nft_trans_chain_update(trans))
+						continue;
+
+					if (nft_hook_list_find(&nft_trans_chain_hooks(trans), h)) {
+						nft_chain_release_hook(&hook);
+						return -EEXIST;
+					}
 				}
 			}
 		} else {
@@ -9060,6 +9075,7 @@ static int nft_flowtable_update(struct nft_ctx *ctx, const struct nlmsghdr *nlh,
 {
 	const struct nlattr * const *nla = ctx->nla;
 	struct nft_flowtable_hook flowtable_hook;
+	struct nftables_pernet *nft_net;
 	struct nft_hook *hook, *next;
 	struct nf_hook_ops *ops;
 	struct nft_trans *trans;
@@ -9076,6 +9092,20 @@ static int nft_flowtable_update(struct nft_ctx *ctx, const struct nlmsghdr *nlh,
 		if (nft_hook_list_find(&flowtable->hook_list, hook)) {
 			list_del(&hook->list);
 			nft_netdev_hook_free(hook);
+			continue;
+		}
+
+		nft_net = nft_pernet(ctx->net);
+		list_for_each_entry(trans, &nft_net->commit_list, list) {
+			if (trans->msg_type != NFT_MSG_NEWFLOWTABLE ||
+			    trans->table != ctx->table ||
+			    !nft_trans_flowtable_update(trans))
+				continue;
+
+			if (nft_hook_list_find(&nft_trans_flowtable_hooks(trans), hook)) {
+				err = -EEXIST;
+				goto err_flowtable_update_hook;
+			}
 		}
 	}
 
-- 
2.49.1

Re: [PATCH net 1/3] netfilter: nft_set_pipapo: fix null deref for empty set

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Florian Westphal <fw@strlen.de>:

On Wed, 13 Aug 2025 13:36:36 +0200 you wrote:
> Blamed commit broke the check for a null scratch map:
>   -  if (unlikely(!m || !*raw_cpu_ptr(m->scratch)))
>   +  if (unlikely(!raw_cpu_ptr(m->scratch)))
> 
> This should have been "if (!*raw_ ...)".
> Use the pattern of the avx2 version which is more readable.
> 
> [...]

Here is the summary with links:
  - [net,1/3] netfilter: nft_set_pipapo: fix null deref for empty set
    https://git.kernel.org/netdev/net/c/30c1d25b9870
  - [net,2/3] ipvs: Fix estimator kthreads preferred affinity
    https://git.kernel.org/netdev/net/c/c0a23bbc98e9
  - [net,3/3] netfilter: nf_tables: reject duplicate device on updates
    https://git.kernel.org/netdev/net/c/cf5fb87fcdaa

You are awesome, thank you!
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