[PATCH net-next 0/6] netfilter: fixes for net-next

[PATCH net-next 0/6] netfilter: fixes for net-next

[Florian Westphal]

Hi,

The following patchset contains Netfilter fixes for *net-next*:

These fixes target next because the bug is either not severe or has
existed for so long that there is no reason to cram them in at the last
minute.

1) Fix IPVS ftp unregistering during netns cleanup, broken since netns
   support was introduced in 2011 in the 2.6.39 kernel.
   From Slavin Liu.
2) nfnetlink must reset the 'nlh' pointer back to the original
   address when a batch is replayed, else we emit bogus ACK messages
   and conceal real errno from userspace.  From Fernando Fernandez Mancera.
   This was broken since 6.10.

3) Recent fix for nftables 'pipapo' set type was incomplete, it only
   made things work for the AVX2 version of the algorithm.

4) Testing revealed another problem with avx2 version that results in
   out-of-bounds read access, this bug always existed since feature was
   added in 5.7 kernel.  This also comes with a selftest update.

Last fix resolves a long-standing bug (since 4.9) in conntrack /proc
interface:
Decrease skip count when we reap an expired entry during dump.
As-is we erronously elide one conntrack entry from dump for every expired
entry seen.  From Eric Dumazet.

Please, pull these changes from:
The following changes since commit dc1dea796b197aba2c3cae25bfef45f4b3ad46fe:

  tcp: Remove stale locking comment for TFO. (2025-09-23 18:21:36 -0700)

are available in the Git repository at:

  https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git tags/nf-next-25-09-24

for you to fetch changes up to c5ba345b2d358b07cc4f07253ba1ada73e77d586:

  netfilter: nf_conntrack: do not skip entries in /proc/net/nf_conntrack (2025-09-24 11:50:28 +0200)

----------------------------------------------------------------
netfilter pull request nf-next-25-09-24

----------------------------------------------------------------
Eric Dumazet (1):
      netfilter: nf_conntrack: do not skip entries in /proc/net/nf_conntrack

Fernando Fernandez Mancera (1):
      netfilter: nfnetlink: reset nlh pointer during batch replay

Florian Westphal (3):
      netfilter: nft_set_pipapo: use 0 genmask for packetpath lookups
      netfilter: nft_set_pipapo_avx2: fix skip of expired entries
      selftests: netfilter: nft_concat_range.sh: add check for double-create bug

Slavin Liu (1):
      ipvs: Defer ip_vs_ftp unregister during netns cleanup

 net/netfilter/ipvs/ip_vs_ftp.c                     |  4 +-
 net/netfilter/nf_conntrack_standalone.c            |  3 ++
 net/netfilter/nfnetlink.c                          |  2 +
 net/netfilter/nft_set_pipapo.c                     |  9 ++--
 net/netfilter/nft_set_pipapo_avx2.c                |  9 ++--
 .../selftests/net/netfilter/nft_concat_range.sh    | 56 +++++++++++++++++++++-
 6 files changed, 73 insertions(+), 10 deletions(-)

[PATCH net-next 1/6] ipvs: Defer ip_vs_ftp unregister during netns cleanup

[Florian Westphal]

From: Slavin Liu <slavin452@gmail.com>

On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp
before connections with valid cp->app pointers are flushed, leading to a
use-after-free.

Fix this by introducing a global `exiting_module` flag, set to true in
ip_vs_ftp_exit() before unregistering the pernet subsystem. In
__ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns
cleanup (when exiting_module is false) and defer it to
__ip_vs_cleanup_batch(), which unregisters all apps after all connections
are flushed. If called during module exit, unregister ip_vs_ftp
immediately.

Fixes: 61b1ab4583e2 ("IPVS: netns, add basic init per netns.")
Suggested-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Slavin Liu <slavin452@gmail.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/ipvs/ip_vs_ftp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
index d8a284999544..206c6700e200 100644
--- a/net/netfilter/ipvs/ip_vs_ftp.c
+++ b/net/netfilter/ipvs/ip_vs_ftp.c
@@ -53,6 +53,7 @@ enum {
 	IP_VS_FTP_EPSV,
 };
 
+static bool exiting_module;
 /*
  * List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper
  * First port is set to the default port.
@@ -605,7 +606,7 @@ static void __ip_vs_ftp_exit(struct net *net)
 {
 	struct netns_ipvs *ipvs = net_ipvs(net);
 
-	if (!ipvs)
+	if (!ipvs || !exiting_module)
 		return;
 
 	unregister_ip_vs_app(ipvs, &ip_vs_ftp);
@@ -627,6 +628,7 @@ static int __init ip_vs_ftp_init(void)
  */
 static void __exit ip_vs_ftp_exit(void)
 {
+	exiting_module = true;
 	unregister_pernet_subsys(&ip_vs_ftp_ops);
 	/* rcu_barrier() is called by netns */
 }
-- 
2.49.1

[PATCH net-next 2/6] netfilter: nfnetlink: reset nlh pointer during batch replay

[Florian Westphal]

From: Fernando Fernandez Mancera <fmancera@suse.de>

During a batch replay, the nlh pointer is not reset until the parsing of
the commands. Since commit bf2ac490d28c ("netfilter: nfnetlink: Handle
ACK flags for batch messages") that is problematic as the condition to
add an ACK for batch begin will evaluate to true even if NLM_F_ACK
wasn't used for batch begin message.

If there is an error during the command processing, netlink is sending
an ACK despite that. This misleads userspace tools which think that the
return code was 0. Reset the nlh pointer to the original one when a
replay is triggered.

Fixes: bf2ac490d28c ("netfilter: nfnetlink: Handle ACK flags for batch messages")
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nfnetlink.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index e598a2a252b0..811d02b4c4f7 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -376,6 +376,7 @@ static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
 	const struct nfnetlink_subsystem *ss;
 	const struct nfnl_callback *nc;
 	struct netlink_ext_ack extack;
+	struct nlmsghdr *onlh = nlh;
 	LIST_HEAD(err_list);
 	u32 status;
 	int err;
@@ -386,6 +387,7 @@ static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
 	status = 0;
 replay_abort:
 	skb = netlink_skb_clone(oskb, GFP_KERNEL);
+	nlh = onlh;
 	if (!skb)
 		return netlink_ack(oskb, nlh, -ENOMEM, NULL);
 
-- 
2.49.1

[PATCH net-next 3/6] netfilter: nft_set_pipapo: use 0 genmask for packetpath lookups

[Florian Westphal]

In commit c4eaca2e1052 ("netfilter: nft_set_pipapo: don't check genbit from
packetpath lookups") I replaced genmask_cur() with NFT_GENMASK_ANY, but
this change has no effect in the pipapo set type.

New entries are unreachable from the active copy, so NFT_GENMASK_ANY has
same result as genmask_cur():

current-gen elements are disabled and the new-generation
elements cannot be found.

Tests did not catch this incomplete fix because the change also dropped
the genmask test from the AVX2 version of the algorithm, so test only
fails if host cpu lacks AVX2 support.

Use genmask test only from the control plane (inserts, deletions, ..).

Packet path has to skip the check, use of 0 is enough for this because
ext->genmask has a the relevant bit set when the element is INACTIVE
in that generation: using a 0 genmask thus makes nft_set_elem_active()
always return true.

Fix the comment and replace NFT_GENMASK_ANY with 0.

Fixes: c4eaca2e1052 ("netfilter: nft_set_pipapo: don't check genbit from packetpath lookups")
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nft_set_pipapo.c      | 9 ++++-----
 net/netfilter/nft_set_pipapo_avx2.c | 2 +-
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
index a7b8fa8cab7c..112fe46788b6 100644
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -549,8 +549,7 @@ static struct nft_pipapo_elem *pipapo_get(const struct nft_pipapo_match *m,
  *
  * This function is called from the data path.  It will search for
  * an element matching the given key in the current active copy.
- * Unlike other set types, this uses NFT_GENMASK_ANY instead of
- * nft_genmask_cur().
+ * Unlike other set types, this uses 0 instead of nft_genmask_cur().
  *
  * This is because new (future) elements are not reachable from
  * priv->match, they get added to priv->clone instead.
@@ -560,8 +559,8 @@ static struct nft_pipapo_elem *pipapo_get(const struct nft_pipapo_match *m,
  * inconsistent state: matching old entries get skipped but thew
  * newly matching entries are unreachable.
  *
- * GENMASK will still find the 'now old' entries which ensures consistent
- * priv->match view.
+ * GENMASK_ANY doesn't work for the same reason: old-gen entries get
+ * skipped, new-gen entries are only reachable from priv->clone.
  *
  * nft_pipapo_commit swaps ->clone and ->match shortly after the
  * genbit flip.  As ->clone doesn't contain the old entries in the first
@@ -578,7 +577,7 @@ nft_pipapo_lookup(const struct net *net, const struct nft_set *set,
 	const struct nft_pipapo_elem *e;
 
 	m = rcu_dereference(priv->match);
-	e = pipapo_get_slow(m, (const u8 *)key, NFT_GENMASK_ANY, get_jiffies_64());
+	e = pipapo_get_slow(m, (const u8 *)key, 0, get_jiffies_64());
 
 	return e ? &e->ext : NULL;
 }
diff --git a/net/netfilter/nft_set_pipapo_avx2.c b/net/netfilter/nft_set_pipapo_avx2.c
index 27dab3667548..e72fd045d037 100644
--- a/net/netfilter/nft_set_pipapo_avx2.c
+++ b/net/netfilter/nft_set_pipapo_avx2.c
@@ -1292,7 +1292,7 @@ nft_pipapo_avx2_lookup(const struct net *net, const struct nft_set *set,
 
 	m = rcu_dereference(priv->match);
 
-	e = pipapo_get_avx2(m, rp, NFT_GENMASK_ANY, get_jiffies_64());
+	e = pipapo_get_avx2(m, rp, 0, get_jiffies_64());
 	local_bh_enable();
 
 	return e ? &e->ext : NULL;
-- 
2.49.1

[PATCH net-next 4/6] netfilter: nft_set_pipapo_avx2: fix skip of expired entries

[Florian Westphal]

KASAN reports following splat:
BUG: KASAN: slab-out-of-bounds in pipapo_get_avx2+0x941/0x25d0
Read of size 1 at addr ffff88814c561be0 by task nft/3944
Call Trace:
 pipapo_get_avx2+0x941/0x25d0
 nft_pipapo_insert+0x440/0x11b0
 nf_tables_newsetelem+0x220a/0x3a00
 ..

This bisects to commit 84c1da7b38d9 ("netfilter: nft_set_pipapo: use AVX2
algorithm for insertions too").

However, that change merely uncovers this bug.

When we find a match but that match has expired or timed out, the AVX2
implementation restarts the full match loop.

At that point, the pointer to the key data has already been changed and
points to the keys last field.
This will then result in out-of-bounds read once its incremented again
for the next field.

The restart logic in AVX2 is different compared to the plain C
implementation, but both should follow the same logic.

The C implementation just calls pipapo_refill() again do check the next
entry.  Do the same in the AVX2 implementation.

Note that with this change, due to implementation differences of
pipapo_refill vs. nft_pipapo_avx2_refill, the refill call will return
the same element again. Then, on the next call, it will move to the next
entry as expected.  This is because avx2_refill doesn't clear the bitmap
in the 'last' conditional.  This is harmless. Expired/timed out elements
are also not expected to be frequent.

selftest is added in a followup commit.

Fixes: 7400b063969b ("nft_set_pipapo: Introduce AVX2-based lookup implementation")
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nft_set_pipapo_avx2.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nft_set_pipapo_avx2.c b/net/netfilter/nft_set_pipapo_avx2.c
index e72fd045d037..7ff90325c97f 100644
--- a/net/netfilter/nft_set_pipapo_avx2.c
+++ b/net/netfilter/nft_set_pipapo_avx2.c
@@ -1179,7 +1179,6 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 
 	nft_pipapo_avx2_prepare();
 
-next_match:
 	nft_pipapo_for_each_field(f, i, m) {
 		bool last = i == m->field_count - 1, first = !i;
 		int ret = 0;
@@ -1226,6 +1225,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 
 #undef NFT_SET_PIPAPO_AVX2_LOOKUP
 
+next_match:
 		if (ret < 0) {
 			scratch->map_index = map_index;
 			kernel_fpu_end();
@@ -1238,8 +1238,11 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 
 			e = f->mt[ret].e;
 			if (unlikely(__nft_set_elem_expired(&e->ext, tstamp) ||
-				     !nft_set_elem_active(&e->ext, genmask)))
+				     !nft_set_elem_active(&e->ext, genmask))) {
+				ret = pipapo_refill(res, f->bsize, f->rules,
+						    fill, f->mt, last);
 				goto next_match;
+			}
 
 			scratch->map_index = map_index;
 			kernel_fpu_end();
-- 
2.49.1

[PATCH net-next 5/6] selftests: netfilter: nft_concat_range.sh: add check for double-create bug

[Florian Westphal]

Add a test case for bug resolved with:
'netfilter: nft_set_pipapo_avx2: fix skip of expired entries'.

It passes on nf.git (it uses the generic/C version for insertion
duplicate check) but fails on unpatched nf-next if AVX2 is supported:

  cannot create same element twice      0s                        [FAIL]
Could create element twice in same transaction
table inet filter { # handle 8
[..]
  elements = { 1.2.3.4 . 1.2.4.1 counter packets 0 bytes 0,
               1.2.4.1 . 1.2.3.4 counter packets 0 bytes 0,
               1.2.3.4 . 1.2.4.1 counter packets 0 bytes 0,
               1.2.4.1 . 1.2.3.4 counter packets 0 bytes 0 }

Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 .../net/netfilter/nft_concat_range.sh         | 56 ++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/netfilter/nft_concat_range.sh b/tools/testing/selftests/net/netfilter/nft_concat_range.sh
index 20e76b395c85..ad97c6227f35 100755
--- a/tools/testing/selftests/net/netfilter/nft_concat_range.sh
+++ b/tools/testing/selftests/net/netfilter/nft_concat_range.sh
@@ -29,7 +29,7 @@ TYPES="net_port port_net net6_port port_proto net6_port_mac net6_port_mac_proto
        net6_port_net6_port net_port_mac_proto_net"
 
 # Reported bugs, also described by TYPE_ variables below
-BUGS="flush_remove_add reload net_port_proto_match avx2_mismatch"
+BUGS="flush_remove_add reload net_port_proto_match avx2_mismatch doublecreate"
 
 # List of possible paths to pktgen script from kernel tree for performance tests
 PKTGEN_SCRIPT_PATHS="
@@ -408,6 +408,18 @@ perf_duration	0
 "
 
 
+TYPE_doublecreate="
+display		cannot create same element twice
+type_spec	ipv4_addr . ipv4_addr
+chain_spec	ip saddr . ip daddr
+dst		addr4
+proto		icmp
+
+race_repeat	0
+
+perf_duration	0
+"
+
 # Set template for all tests, types and rules are filled in depending on test
 set_template='
 flush ruleset
@@ -1900,6 +1912,48 @@ test_bug_avx2_mismatch()
 	fi
 }
 
+test_bug_doublecreate()
+{
+	local elements="1.2.3.4 . 1.2.4.1, 1.2.4.1 . 1.2.3.4"
+	local ret=1
+	local i
+
+	setup veth send_"${proto}" set || return ${ksft_skip}
+
+	add "{ $elements }" || return 1
+	# expected to work: 'add' on existing should be no-op.
+	add "{ $elements }" || return 1
+
+	# 'create' should return an error.
+	if nft create element inet filter test "{ $elements }" 2>/dev/null; then
+		err "Could create an existing element"
+		return 1
+	fi
+nft -f - <<EOF 2>/dev/null
+flush set inet filter test
+create element inet filter test { $elements }
+create element inet filter test { $elements }
+EOF
+	ret=$?
+	if [ $ret -eq 0 ]; then
+		err "Could create element twice in one transaction"
+		err "$(nft -a list ruleset)"
+		return 1
+	fi
+
+nft -f - <<EOF 2>/dev/null
+flush set inet filter test
+create element inet filter test { $elements }
+EOF
+	ret=$?
+	if [ $ret -ne 0 ]; then
+		err "Could not flush and re-create element in one transaction"
+		return 1
+	fi
+
+	return 0
+}
+
 test_reported_issues() {
 	eval test_bug_"${subtest}"
 }
-- 
2.49.1

[PATCH net-next 6/6] netfilter: nf_conntrack: do not skip entries in /proc/net/nf_conntrack

[Florian Westphal]

From: Eric Dumazet <edumazet@google.com>

ct_seq_show() has an opportunistic garbage collector :

if (nf_ct_should_gc(ct)) {
    nf_ct_kill(ct);
    goto release;
}

So if one nf_conn is killed there, next time ct_get_next() runs,
we skip the following item in the bucket, even if it should have
been displayed if gc did not take place.

We can decrement st->skip_elems to tell ct_get_next() one of the items
was removed from the chain.

Fixes: 58e207e4983d ("netfilter: evict stale entries when user reads /proc/net/nf_conntrack")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nf_conntrack_standalone.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 1f14ef0436c6..708b79380f04 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -317,6 +317,9 @@ static int ct_seq_show(struct seq_file *s, void *v)
 	smp_acquire__after_ctrl_dep();
 
 	if (nf_ct_should_gc(ct)) {
+		struct ct_iter_state *st = s->private;
+
+		st->skip_elems--;
 		nf_ct_kill(ct);
 		goto release;
 	}
-- 
2.49.1

Re: [PATCH net-next 0/6] netfilter: fixes for net-next

[Pablo Neira Ayuso]

Trimming Cc:

On Wed, Sep 24, 2025 at 04:06:48PM +0200, Florian Westphal wrote:
> Hi,
> 
> The following patchset contains Netfilter fixes for *net-next*:
> 
> These fixes target next because the bug is either not severe or has
> existed for so long that there is no reason to cram them in at the last
> minute.
> 
> 1) Fix IPVS ftp unregistering during netns cleanup, broken since netns
>    support was introduced in 2011 in the 2.6.39 kernel.
>    From Slavin Liu.
> 2) nfnetlink must reset the 'nlh' pointer back to the original
>    address when a batch is replayed, else we emit bogus ACK messages
>    and conceal real errno from userspace.  From Fernando Fernandez Mancera.
>    This was broken since 6.10.

Side note: nftables userspace does not use this feature. This is used
by a tool that is not in the netfilter.org repositories, to my
knowledged.

> 3) Recent fix for nftables 'pipapo' set type was incomplete, it only
>    made things work for the AVX2 version of the algorithm.
> 
> 4) Testing revealed another problem with avx2 version that results in
>    out-of-bounds read access, this bug always existed since feature was
>    added in 5.7 kernel.  This also comes with a selftest update.
> 
> Last fix resolves a long-standing bug (since 4.9) in conntrack /proc
> interface:
> Decrease skip count when we reap an expired entry during dump.
> As-is we erronously elide one conntrack entry from dump for every expired
> entry seen.  From Eric Dumazet.
> 
> Please, pull these changes from:
> The following changes since commit dc1dea796b197aba2c3cae25bfef45f4b3ad46fe:
> 
>   tcp: Remove stale locking comment for TFO. (2025-09-23 18:21:36 -0700)
> 
> are available in the Git repository at:
> 
>   https://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git tags/nf-next-25-09-24
> 
> for you to fetch changes up to c5ba345b2d358b07cc4f07253ba1ada73e77d586:
> 
>   netfilter: nf_conntrack: do not skip entries in /proc/net/nf_conntrack (2025-09-24 11:50:28 +0200)
> 
> ----------------------------------------------------------------
> netfilter pull request nf-next-25-09-24
> 
> ----------------------------------------------------------------
> Eric Dumazet (1):
>       netfilter: nf_conntrack: do not skip entries in /proc/net/nf_conntrack
> 
> Fernando Fernandez Mancera (1):
>       netfilter: nfnetlink: reset nlh pointer during batch replay
> 
> Florian Westphal (3):
>       netfilter: nft_set_pipapo: use 0 genmask for packetpath lookups
>       netfilter: nft_set_pipapo_avx2: fix skip of expired entries
>       selftests: netfilter: nft_concat_range.sh: add check for double-create bug
> 
> Slavin Liu (1):
>       ipvs: Defer ip_vs_ftp unregister during netns cleanup
> 
>  net/netfilter/ipvs/ip_vs_ftp.c                     |  4 +-
>  net/netfilter/nf_conntrack_standalone.c            |  3 ++
>  net/netfilter/nfnetlink.c                          |  2 +
>  net/netfilter/nft_set_pipapo.c                     |  9 ++--
>  net/netfilter/nft_set_pipapo_avx2.c                |  9 ++--
>  .../selftests/net/netfilter/nft_concat_range.sh    | 56 +++++++++++++++++++++-
>  6 files changed, 73 insertions(+), 10 deletions(-)

Re: [PATCH net-next 0/6] netfilter: fixes for net-next

[Fernando Fernandez Mancera]

On 9/25/25 12:29 AM, Pablo Neira Ayuso wrote:
> Trimming Cc:
> 
> On Wed, Sep 24, 2025 at 04:06:48PM +0200, Florian Westphal wrote:
>> Hi,
>>
>> The following patchset contains Netfilter fixes for *net-next*:
>>
>> These fixes target next because the bug is either not severe or has
>> existed for so long that there is no reason to cram them in at the last
>> minute.
>>
>> 1) Fix IPVS ftp unregistering during netns cleanup, broken since netns
>>     support was introduced in 2011 in the 2.6.39 kernel.
>>     From Slavin Liu.
>> 2) nfnetlink must reset the 'nlh' pointer back to the original
>>     address when a batch is replayed, else we emit bogus ACK messages
>>     and conceal real errno from userspace.  From Fernando Fernandez Mancera.
>>     This was broken since 6.10.
> 
> Side note: nftables userspace does not use this feature. This is used
> by a tool that is not in the netfilter.org repositories, to my
> knowledged.
> 

Yes, that is right. It was found in an external tool using libnftnl 
directly. FWIW, the libnftnl examples also uses the NLM_F_ACK for the 
messages containing data as new rule, chain, table..

Re: [PATCH net-next 1/6] ipvs: Defer ip_vs_ftp unregister during netns cleanup

[patchwork-bot+netdevbpf]

Hello:

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

On Wed, 24 Sep 2025 16:06:49 +0200 you wrote:
> From: Slavin Liu <slavin452@gmail.com>
> 
> On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp
> before connections with valid cp->app pointers are flushed, leading to a
> use-after-free.
> 
> Fix this by introducing a global `exiting_module` flag, set to true in
> ip_vs_ftp_exit() before unregistering the pernet subsystem. In
> __ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns
> cleanup (when exiting_module is false) and defer it to
> __ip_vs_cleanup_batch(), which unregisters all apps after all connections
> are flushed. If called during module exit, unregister ip_vs_ftp
> immediately.
> 
> [...]

Here is the summary with links:
  - [net-next,1/6] ipvs: Defer ip_vs_ftp unregister during netns cleanup
    https://git.kernel.org/netdev/net-next/c/134121bfd99a
  - [net-next,2/6] netfilter: nfnetlink: reset nlh pointer during batch replay
    https://git.kernel.org/netdev/net-next/c/09efbac953f6
  - [net-next,3/6] netfilter: nft_set_pipapo: use 0 genmask for packetpath lookups
    https://git.kernel.org/netdev/net-next/c/4dbac7db17f1
  - [net-next,4/6] netfilter: nft_set_pipapo_avx2: fix skip of expired entries
    https://git.kernel.org/netdev/net-next/c/5823699a11cf
  - [net-next,5/6] selftests: netfilter: nft_concat_range.sh: add check for double-create bug
    https://git.kernel.org/netdev/net-next/c/94bd247bc25b
  - [net-next,6/6] netfilter: nf_conntrack: do not skip entries in /proc/net/nf_conntrack
    https://git.kernel.org/netdev/net-next/c/c5ba345b2d35

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH net-next 0/6] netfilter: fixes for net-next

[Nikolaos Gkarlis]

Hi,

I was wondering whether it would be possible to submit a backport of
Fernando's fix to the affected LTS releases, if that is not already
planned.

I'm asking because this bug broke an unofficial Go library that I use:
https://github.com/google/nftables/issues/329.

If you think that would be appropriate, I'd be happy to help move this
forward in any way I can.

Thanks!

Re: [PATCH net-next 0/6] netfilter: fixes for net-next

[Florian Westphal]

Nikolaos Gkarlis <nickgarlis@gmail.com> wrote:
> I was wondering whether it would be possible to submit a backport of
> Fernando's fix to the affected LTS releases, if that is not already
> planned.

09efbac953f6 ("netfilter: nfnetlink: reset nlh pointer during batch replay")
has all needed tags to get picked up by -stable team.

It applies cleanly all the way back to 6.12.y.  Earlioer
maintained releases are not affected.