[PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[Pablo Neira Ayuso]

Hi,

The following patchset contains Netfilter/IPVS updates for net-next:

1) Disable br_netfilter in userns and schedule it for removal in 2027,
   from Florian Westphal.

2) Prepare the flowtable to support for IPv4 over IPv6 tunneling and
   vice-versa, this includes 5 patches from Lorenzo Bianconi.

3) Update selftest nft_queue.sh to make it more stable on debug
   kernels, from Jakub Kicinski.

4) Fix a overflow in IPVS sync messages which can only happen in very
   old 2.6 kernels, from Julian Anastasov.

5) Flush conntrack gc worker when existing netns to address a unlikely
   UaF, from Florian Westphal.

6) Switch nf_tables chain types to use rcu, otherwise module removal
   can trigger UaF, also from Florian.

7) Add two new helper functions to validate that socket is of inet type,
   coming in 2 patches from Florian Westphal.

8) Remove redundant parsing in nft_exthdr for the tcp options case,
   from Fernando F. Mancera.

9) Remove redundant skb_header_pointer() calls in nft_exthdr for tcp
   options, from Fernando F. Mancera.

Please, pull these changes from:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git nf-next-26-10-11

Thanks.

----------------------------------------------------------------

The following changes since commit a5e7d8e446af9803e37a3b6a4d416fb41178348f:

  Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue (2026-10-05 17:51:32 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git nf-next-26-10-11

for you to fetch changes up to b4074bbf5c23b05bd34022ade979f3d5f4e86516:

  netfilter: nft_exthdr: avoid 60 bytes stack buffer in TCP option mangling (2026-10-11 23:29:26 +0200)

----------------------------------------------------------------
netfilter pull request 26-10-11

----------------------------------------------------------------
Fernando Fernandez Mancera (2):
      netfilter: nft_exthdr: remove redundant op parsing in tcp_set_init
      netfilter: nft_exthdr: avoid 60 bytes stack buffer in TCP option mangling

Florian Westphal (5):
      netfilter: disable br_netfilter in user namespaces
      netfilter: conntrack: fix unlikely UaF in gc worker
      netfilter: nf_tables: switch chain_types array to rcu
      netfilter: add nf_skb_sk helper and use it
      netfilter: add nf_sk_to_full_sk helper and use it

Jakub Kicinski (1):
      selftests: netfilter: nft_queue.sh: only queue icmp echo request/reply

Julian Anastasov (1):
      ipvs: fix buffer overflow when sending sync messages

Lorenzo Bianconi (6):
      netfilter: flowtable: recognize IPv4/IPv6 in tunnel proto matching
      netfilter: flowtable: set inner protocol when popping tunnel header
      netfilter: flowtable: populate tunnel tuple regardless of inner protocol
      netfilter: flowtable: add encap_proto to flow_offload_tunnel
      netfilter: flowtable: refactor MTU check for tunnel offload
      netfilter: flowtable: unify tunnel push for IPv4 and IPv6

 Documentation/networking/bridge.rst                |   5 +-
 include/linux/netdevice.h                          |   1 +
 include/net/netfilter/nf_flow_table.h              |   1 +
 include/net/netfilter/nf_socket.h                  |  35 ++++
 net/bridge/br_netfilter_hooks.c                    |  33 +++-
 net/ipv4/ipip.c                                    |   1 +
 net/ipv4/netfilter.c                               |   3 +-
 net/ipv6/ip6_tunnel.c                              |   1 +
 net/ipv6/netfilter.c                               |   3 +-
 net/netfilter/ipvs/ip_vs_sync.c                    |  23 ++-
 net/netfilter/nf_conntrack_core.c                  |   5 +
 net/netfilter/nf_flow_table_ip.c                   | 215 +++++++++++++--------
 net/netfilter/nf_flow_table_path.c                 |   2 +
 net/netfilter/nf_tables_api.c                      |  94 ++++++---
 net/netfilter/nft_chain_nat.c                      |   1 +
 net/netfilter/nft_exthdr.c                         |  34 ++--
 net/netfilter/nft_socket.c                         |  16 +-
 net/netfilter/xt_socket.c                          |  26 +--
 tools/testing/selftests/net/netfilter/nft_queue.sh |   2 +-
 19 files changed, 336 insertions(+), 165 deletions(-)

[PATCH net-next 01/15] netfilter: disable br_netfilter in user namespaces

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

br_netfilter has way too many bugs, schedule for removal and disable
the feature in user namespaces.

In particular, we get more and more gadgets to have bridge ports escape
rcu_read_lock() protection, then underlying device gets reconfigured
(macvlan or something else), then reinject into network stack causes
crash because net_device is assumed to still have bridge rx data
associated with it.

br_netfilter is an ancient kludge that emulates ip stack from within the
bridge and then calls into ipv4/ipv6 netfilter hooks to have bridged
frames processed via iptables/ip6tables by setting the 'call-iptables'
sysctls to 1. It is NOT related to ebtables or nftables 'bridge' family
at all.

Note that in addition to call-iptables, sysctls, the bridge also exposes
call-iptables per bridge device via netlink and sysfs
('BROPT_NF_CALL_IPTABLES') toggles.

Those are still available, the brnet structure is scoped to br_netfilter;
exposing it bridge-wide is a big no-no.

This relies on brnf_device_event() no longer registering the base
br_netfilter hooks, so while BROPT_NF_CALL_IPTABLES can be set, it
has no effect because the hooks that evaluate this feature bit
are never registered.

brnf_init_net can no longer depend on CONFIG_SYSCTL, else such builds
never disable support in user namespaces.

Cc: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 Documentation/networking/bridge.rst |  5 +++--
 net/bridge/br_netfilter_hooks.c     | 33 ++++++++++++++++++++---------
 2 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/Documentation/networking/bridge.rst b/Documentation/networking/bridge.rst
index c1e6ea52c9e5..dded1a6edd60 100644
--- a/Documentation/networking/bridge.rst
+++ b/Documentation/networking/bridge.rst
@@ -277,8 +277,9 @@ Netfilter
 =========
 
 The bridge netfilter module is a legacy feature that allows to filter bridged
-packets with iptables and ip6tables. Its use is discouraged. Users should
-consider using nftables for packet filtering.
+packets with iptables and ip6tables. This feature is scheduled for removal and
+not available in user namespaces. Consider using nftables for packet filtering
+instead.
 
 The older ebtables tool is more feature-limited compared to nftables, but
 just like nftables it doesn't need this module either to function.
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 0a394e5f4391..e15355ff215a 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -54,6 +54,7 @@ static unsigned int brnf_net_id __read_mostly;
 
 struct brnf_net {
 	bool enabled;
+	bool in_userns;
 
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header *ctl_hdr;
@@ -1100,7 +1101,7 @@ static int brnf_device_event(struct notifier_block *unused, unsigned long event,
 
 	net = dev_net(dev);
 	brnet = net_generic(net, brnf_net_id);
-	if (brnet->enabled)
+	if (brnet->enabled || brnet->in_userns)
 		return NOTIFY_OK;
 
 	ret = nf_register_net_hooks(net, br_nf_ops, ARRAY_SIZE(br_nf_ops));
@@ -1229,9 +1230,11 @@ static inline void br_netfilter_sysctl_default(struct brnf_net *brnf)
 	brnf->filter_pppoe_tagged = 0;
 	brnf->pass_vlan_indev = 0;
 }
+#endif
 
 static int br_netfilter_sysctl_init_net(struct net *net)
 {
+#ifdef CONFIG_SYSCTL
 	struct ctl_table *table = brnf_table;
 	struct brnf_net *brnet;
 
@@ -1259,25 +1262,39 @@ static int br_netfilter_sysctl_init_net(struct net *net)
 
 		return -ENOMEM;
 	}
-
+#endif
 	return 0;
 }
 
 static void br_netfilter_sysctl_exit_net(struct net *net,
 					 struct brnf_net *brnet)
 {
-	const struct ctl_table *table = brnet->ctl_hdr->ctl_table_arg;
+#ifdef CONFIG_SYSCTL
+	struct ctl_table_header *header = brnet->ctl_hdr;
+	const struct ctl_table *table;
 
-	unregister_net_sysctl_table(brnet->ctl_hdr);
+	if (!header)
+		return;
+
+	table = header->ctl_table_arg;
+	unregister_net_sysctl_table(header);
 	if (!net_eq(net, &init_net))
 		kfree(table);
+#endif
 }
 
 static int __net_init brnf_init_net(struct net *net)
 {
+	if (net->user_ns != &init_user_ns) {
+		struct brnf_net *brnet = net_generic(net, brnf_net_id);
+
+		brnet->in_userns = true;
+		pr_warn_once("br_netfilter no longer supported in user namespaces\n");
+		return 0;
+	}
+
 	return br_netfilter_sysctl_init_net(net);
 }
-#endif
 
 static void __net_exit brnf_exit_net(struct net *net)
 {
@@ -1289,15 +1306,11 @@ static void __net_exit brnf_exit_net(struct net *net)
 		brnet->enabled = false;
 	}
 
-#ifdef CONFIG_SYSCTL
 	br_netfilter_sysctl_exit_net(net, brnet);
-#endif
 }
 
 static struct pernet_operations brnf_net_ops __read_mostly = {
-#ifdef CONFIG_SYSCTL
 	.init = brnf_init_net,
-#endif
 	.exit = brnf_exit_net,
 	.id   = &brnf_net_id,
 	.size = sizeof(struct brnf_net),
@@ -1318,7 +1331,7 @@ static int __init br_netfilter_init(void)
 	}
 
 	RCU_INIT_POINTER(nf_br_ops, &br_ops);
-	printk(KERN_NOTICE "Bridge firewalling registered\n");
+	pr_warn("br_netfilter is slated for removal in 2027.\n");
 	return 0;
 }
 
-- 
2.47.3

[PATCH net-next 02/15] netfilter: flowtable: recognize IPv4/IPv6 in tunnel proto matching

[Pablo Neira Ayuso]

From: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

Allow the flowtable to parse IPv4-in-IPv6 and IPv6-in-IPv4 tunnels by
accepting both IPPROTO_IPIP and IPPROTO_IPV6 as the inner protocol when
walking the outer header in nf_flow_ip4_tunnel_proto() and
nf_flow_ip6_tunnel_proto(). This is a preliminary patch to support IPv4
over IPv6 and SIT tunnel flowtable offload.
Please note IPv4 over IPv6 and SIT tunnel flowtable offloading is not
enabled yet.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_ip.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index c8c29a9a1684..42e8de696474 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -326,7 +326,7 @@ static bool nf_flow_ip4_tunnel_proto(struct nf_flowtable_ctx *ctx,
 	if (iph->ttl <= 1)
 		return false;
 
-	if (iph->protocol == IPPROTO_IPIP) {
+	if (iph->protocol == IPPROTO_IPIP || iph->protocol == IPPROTO_IPV6) {
 		ctx->tun.inner_proto = iph->protocol;
 		ctx->tun.hdr_size = size;
 		ctx->offset += ctx->tun.hdr_size;
@@ -351,7 +351,7 @@ static bool nf_flow_ip6_tunnel_proto(struct nf_flowtable_ctx *ctx,
 	if (ipv6_ext_hdr(ip6h->nexthdr))
 		return false;
 
-	if (ip6h->nexthdr == IPPROTO_IPV6) {
+	if (ip6h->nexthdr == IPPROTO_IPIP || ip6h->nexthdr == IPPROTO_IPV6) {
 		ctx->tun.inner_proto = ip6h->nexthdr;
 		ctx->tun.hdr_size = sizeof(*ip6h);
 		ctx->offset += ctx->tun.hdr_size;
-- 
2.47.3

[PATCH net-next 03/15] netfilter: flowtable: set inner protocol when popping tunnel header

[Pablo Neira Ayuso]

From: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

Pop the outer tunnel header and set skb->protocol to the inner protocol
derived from ctx->tun.inner_proto in nf_flow_ip_tunnel_pop(), instead of
bailing out unless the tunnel carries IP-in-IP or IPv6-in-IPv6.
This is a preliminary patch to support IPv4 over IPv6 and SIT tunnel
flowtable offload.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_ip.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 42e8de696474..cd636b4cf74b 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -372,6 +372,11 @@ static void nf_flow_ip_tunnel_pop(struct nf_flowtable_ctx *ctx,
 
 	skb_pull(skb, ctx->tun.hdr_size);
 	skb_reset_network_header(skb);
+
+	if (ctx->tun.inner_proto == IPPROTO_IPIP)
+		skb->protocol = htons(ETH_P_IP);
+	else
+		skb->protocol = htons(ETH_P_IPV6);
 }
 
 static bool nf_flow_skb_encap_protocol(struct nf_flowtable_ctx *ctx,
-- 
2.47.3

[PATCH net-next 04/15] netfilter: flowtable: populate tunnel tuple regardless of inner protocol

[Pablo Neira Ayuso]

From: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

Store the outer tunnel addresses and inner protocol in the flow tuple
unconditionally in nf_flow_tuple_encap(), instead of only when the
tunnel is IP-in-IP or IPv6-in-IPv6. Bail out early when the inner
protocol is neither IPPROTO_IPIP nor IPPROTO_IPV6.
This makes the tuple usable for cross-family tunnels such as
IPv4-over-IPv6 and SIT, where the inner protocol differs from the
outer address family.
This is a preliminary patch to support IPv4 over IPv6 and SIT tunnel
flowtable offload.
Please note IPv4 over IPv6 and SIT tunnel flowtable offloading is not
enabled yet.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_ip.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index cd636b4cf74b..a53393f8eda0 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -189,22 +189,22 @@ static void nf_flow_tuple_encap(struct nf_flowtable_ctx *ctx,
 		break;
 	}
 
+	if (ctx->tun.inner_proto != IPPROTO_IPIP &&
+	    ctx->tun.inner_proto != IPPROTO_IPV6)
+		return;
+
 	switch (ctx->ether_type) {
 	case htons(ETH_P_IP):
 		iph = (struct iphdr *)(skb_network_header(skb) + offset);
-		if (ctx->tun.inner_proto == IPPROTO_IPIP) {
-			tuple->tun.dst_v4.s_addr = iph->daddr;
-			tuple->tun.src_v4.s_addr = iph->saddr;
-			tuple->tun.inner_proto = IPPROTO_IPIP;
-		}
+		tuple->tun.dst_v4.s_addr = iph->daddr;
+		tuple->tun.src_v4.s_addr = iph->saddr;
+		tuple->tun.inner_proto = ctx->tun.inner_proto;
 		break;
 	case htons(ETH_P_IPV6):
 		ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
-		if (ctx->tun.inner_proto == IPPROTO_IPV6) {
-			tuple->tun.dst_v6 = ip6h->daddr;
-			tuple->tun.src_v6 = ip6h->saddr;
-			tuple->tun.inner_proto = IPPROTO_IPV6;
-		}
+		tuple->tun.dst_v6 = ip6h->daddr;
+		tuple->tun.src_v6 = ip6h->saddr;
+		tuple->tun.inner_proto = ctx->tun.inner_proto;
 		break;
 	default:
 		break;
-- 
2.47.3

[PATCH net-next 05/15] netfilter: flowtable: add encap_proto to flow_offload_tunnel

[Pablo Neira Ayuso]

From: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

Add encap_proto (AF_INET or AF_INET6) to struct flow_offload_tunnel
to allow its use as part of the hash table key during flowtable entry
lookup.
This is a preliminary change to support IPv4 over IPv6 tunneling via
the flowtable infrastructure for software acceleration.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/linux/netdevice.h             | 1 +
 include/net/netfilter/nf_flow_table.h | 1 +
 net/ipv4/ipip.c                       | 1 +
 net/ipv6/ip6_tunnel.c                 | 1 +
 net/netfilter/nf_flow_table_ip.c      | 2 ++
 net/netfilter/nf_flow_table_path.c    | 2 ++
 6 files changed, 8 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f61c97231309..fee3728ad666 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -911,6 +911,7 @@ struct net_device_path {
 			};
 
 			u8	inner_proto;
+			u8	encap_proto;
 		} tun;
 		struct {
 			enum {
diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h
index 5b611efaa3cd..5b22d31cb140 100644
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -118,6 +118,7 @@ struct flow_offload_tunnel {
 	};
 
 	u8	inner_proto;
+	u8	encap_proto;
 };
 
 struct flow_offload_tuple {
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 2ffe64e736e0..15189e1fa068 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -379,6 +379,7 @@ static int ipip_fill_forward_path(struct net_device_path_ctx *ctx,
 	path->tun.src_v4.s_addr = tiph->saddr;
 	path->tun.dst_v4.s_addr = tiph->daddr;
 	path->tun.inner_proto = IPPROTO_IPIP;
+	path->tun.encap_proto = AF_INET;
 	path->tun.dst = &rt->dst;
 	path->dev = ctx->dev;
 
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index d5ff50a2ac01..64a184bca467 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1868,6 +1868,7 @@ static int ip6_tnl_fill_forward_path(struct net_device_path_ctx *ctx,
 		path->tun.src_v6 = fl6.saddr;
 		path->tun.dst_v6 = fl6.daddr;
 		path->tun.inner_proto = IPPROTO_IPV6;
+		path->tun.encap_proto = AF_INET6;
 		path->tun.dst = dst;
 		path->dev = ctx->dev;
 		ctx->dev = dst->dev;
diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index a53393f8eda0..1b9360d54dfc 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -199,12 +199,14 @@ static void nf_flow_tuple_encap(struct nf_flowtable_ctx *ctx,
 		tuple->tun.dst_v4.s_addr = iph->daddr;
 		tuple->tun.src_v4.s_addr = iph->saddr;
 		tuple->tun.inner_proto = ctx->tun.inner_proto;
+		tuple->tun.encap_proto = AF_INET;
 		break;
 	case htons(ETH_P_IPV6):
 		ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
 		tuple->tun.dst_v6 = ip6h->daddr;
 		tuple->tun.src_v6 = ip6h->saddr;
 		tuple->tun.inner_proto = ctx->tun.inner_proto;
+		tuple->tun.encap_proto = AF_INET6;
 		break;
 	default:
 		break;
diff --git a/net/netfilter/nf_flow_table_path.c b/net/netfilter/nf_flow_table_path.c
index d90013685bf1..841f099434d9 100644
--- a/net/netfilter/nf_flow_table_path.c
+++ b/net/netfilter/nf_flow_table_path.c
@@ -138,6 +138,7 @@ static int nft_dev_path_info(struct net_device_path_stack *stack,
 				info->tun.dst_v6 = path->tun.dst_v6;
 				info->tun.inner_proto = path->tun.inner_proto;
 				info->tun_dst = path->tun.dst;
+				info->tun.encap_proto = path->tun.encap_proto;
 				info->num_tuns++;
 			} else {
 				if (info->num_encaps >= NF_FLOW_TABLE_ENCAP_MAX)
@@ -249,6 +250,7 @@ static int nft_dev_forward_path(const struct nft_pktinfo *pkt,
 		route->tuple[!dir].in.tun.src_v6 = info.tun.dst_v6;
 		route->tuple[!dir].in.tun.dst_v6 = info.tun.src_v6;
 		route->tuple[!dir].in.tun.inner_proto = info.tun.inner_proto;
+		route->tuple[!dir].in.tun.encap_proto = info.tun.encap_proto;
 		route->tuple[!dir].in.num_tuns = info.num_tuns;
 		dst_release(route->tuple[dir].dst);
 		route->tuple[dir].dst = info.tun_dst;
-- 
2.47.3

[PATCH net-next 06/15] netfilter: flowtable: refactor MTU check for tunnel offload

[Pablo Neira Ayuso]

From: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

Introduce nf_flow_offload_check_mtu() helper and use the encapsulated
protocol (tun.encap_proto) to compute the tunnel overhead instead of
relying on tun_num, so the correct inner header size (IPv4 vs IPv6) is
accounted for. Use it in both the IPv4 and IPv6 forward paths.
This is a preliminary patch to support IPv4 over IPv6 and SIT flowtable
tunnel offload.
Please note IPv4 over IPv6 and SIT tunnel flowtable offloading is not
enabled yet.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_ip.c | 41 ++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 1b9360d54dfc..96dbdadba4e7 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -472,6 +472,31 @@ nf_flow_offload_lookup(struct nf_flowtable_ctx *ctx,
 	return flow_offload_lookup(flow_table, &tuple);
 }
 
+static int nf_flow_offload_check_mtu(struct nf_flowtable_ctx *ctx,
+				     struct flow_offload *flow,
+				     enum flow_offload_tuple_dir dir,
+				     struct sk_buff *skb)
+{
+	unsigned int mtu;
+
+	mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset;
+	switch (flow->tuplehash[!dir].tuple.tun.encap_proto) {
+	case AF_INET:
+		mtu -= sizeof(struct iphdr);
+		break;
+	case AF_INET6:
+		mtu -= sizeof(struct ipv6hdr);
+		break;
+	default:
+		break;
+	}
+
+	if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx,
 				   struct nf_flowtable *flow_table,
 				   struct flow_offload_tuple_rhash *tuplehash,
@@ -479,17 +504,13 @@ static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx,
 {
 	enum flow_offload_tuple_dir dir;
 	struct flow_offload *flow;
-	unsigned int thoff, mtu;
+	unsigned int thoff;
 	struct iphdr *iph;
 
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 
-	mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset;
-	if (flow->tuplehash[!dir].tuple.tun_num)
-		mtu -= sizeof(*iph);
-
-	if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
+	if (nf_flow_offload_check_mtu(ctx, flow, dir, skb))
 		return 0;
 
 	iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset);
@@ -1075,17 +1096,13 @@ static int nf_flow_offload_ipv6_forward(struct nf_flowtable_ctx *ctx,
 {
 	enum flow_offload_tuple_dir dir;
 	struct flow_offload *flow;
-	unsigned int thoff, mtu;
 	struct ipv6hdr *ip6h;
+	unsigned int thoff;
 
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 
-	mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset;
-	if (flow->tuplehash[!dir].tuple.tun_num)
-		mtu -= sizeof(*ip6h);
-
-	if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
+	if (nf_flow_offload_check_mtu(ctx, flow, dir, skb))
 		return 0;
 
 	ip6h = (struct ipv6hdr *)(skb_network_header(skb) + ctx->offset);
-- 
2.47.3

[PATCH net-next 07/15] netfilter: flowtable: unify tunnel push for IPv4 and IPv6

[Pablo Neira Ayuso]

From: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>

Refactor nf_flow_tunnel_ipip_push() and nf_flow_tunnel_ip6ip6_push()
into nf_flow_tunnel_ip_push() and nf_flow_tunnel_ip6_push(), keying the
inner header handling off tuple->tun.inner_proto so both IP-in-IP and
IPv6-in-IPv6 inner protocols are supported regardless of the outer
address family. Replace nf_flow_tunnel_v4_push() and
nf_flow_tunnel_v6_push() with a single nf_flow_tunnel_push() that
dispatches on tuple->tun.encap_proto, and set skb->protocol explicitly
after pushing the outer header.
This is a preliminary patch to support IPv4 over IPv6 and SIT tunnel
flowtable offload.
Please note IPv4 over IPv6 and SIT tunnel flowtable offloading is not
enabled yet.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_ip.c | 143 +++++++++++++++++++------------
 1 file changed, 87 insertions(+), 56 deletions(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index 96dbdadba4e7..7a62a70593ed 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -608,23 +608,44 @@ static int nf_flow_pppoe_push(struct sk_buff *skb, u16 id,
 	return 0;
 }
 
-static int nf_flow_tunnel_ipip_push(struct net *net, struct sk_buff *skb,
-				    struct flow_offload_tuple *tuple,
-				    struct dst_entry *dst, __be32 *ip_daddr)
+static int nf_flow_tunnel_ip_push(struct net *net, struct sk_buff *skb,
+				  struct flow_offload_tuple *tuple,
+				  struct dst_entry *dst,
+				  union nf_inet_addr **ip_addr)
 {
-	struct iphdr *iph = (struct iphdr *)skb_network_header(skb);
-	struct rtable *rt = dst_rtable(dst);
-	u8 tos = iph->tos, ttl = iph->ttl;
-	__be16 frag_off = iph->frag_off;
-	u32 headroom = sizeof(*iph);
+	__be16 frag_off = 0;
+	struct iphdr *iph;
+	u8 tos = 0, ttl;
+	u32 headroom;
 	int err;
 
+	switch (tuple->tun.inner_proto) {
+	case IPPROTO_IPV6: {
+		struct ipv6hdr *ip6h;
+
+		ip6h = (struct ipv6hdr *)skb_network_header(skb);
+		tos = ipv6_get_dsfield(ip6h);
+		ttl = ip6h->hop_limit;
+		frag_off = htons(IP_DF);
+		break;
+	}
+	case IPPROTO_IPIP:
+		iph = (struct iphdr *)skb_network_header(skb);
+		frag_off = iph->frag_off;
+		tos = iph->tos;
+		ttl = iph->ttl;
+		break;
+	default:
+		return 0;
+	}
+
 	err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4);
 	if (err)
 		return err;
 
-	skb_set_inner_ipproto(skb, IPPROTO_IPIP);
-	headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
+	skb_set_inner_ipproto(skb, tuple->tun.inner_proto);
+	headroom = sizeof(*iph) + LL_RESERVED_SPACE(dst->dev) +
+		   dst->header_len;
 	err = skb_cow_head(skb, headroom);
 	if (err)
 		return err;
@@ -635,11 +656,12 @@ static int nf_flow_tunnel_ipip_push(struct net *net, struct sk_buff *skb,
 	/* Push down and install the IP header. */
 	skb_push(skb, sizeof(*iph));
 	skb_reset_network_header(skb);
+	skb->protocol = htons(ETH_P_IP);
 
 	iph = ip_hdr(skb);
 	iph->version	= 4;
 	iph->ihl	= sizeof(*iph) >> 2;
-	iph->frag_off	= ip_mtu_locked(&rt->dst) ? 0 : frag_off;
+	iph->frag_off	= ip_mtu_locked(dst) ? 0 : frag_off;
 	iph->protocol	= tuple->tun.inner_proto;
 	iph->tos	= tos;
 	iph->daddr	= tuple->tun.src_v4.s_addr;
@@ -649,81 +671,91 @@ static int nf_flow_tunnel_ipip_push(struct net *net, struct sk_buff *skb,
 	__ip_select_ident(net, iph, skb_shinfo(skb)->gso_segs ?: 1);
 	ip_send_check(iph);
 
-	*ip_daddr = tuple->tun.src_v4.s_addr;
-
-	return 0;
-}
-
-static int nf_flow_tunnel_v4_push(struct net *net, struct sk_buff *skb,
-				  struct flow_offload_tuple *tuple,
-				  struct dst_entry *dst,  __be32 *ip_daddr)
-{
-	if (tuple->tun_num)
-		return nf_flow_tunnel_ipip_push(net, skb, tuple, dst, ip_daddr);
+	*ip_addr = (union nf_inet_addr *)&tuple->tun.src_v4;
 
 	return 0;
 }
 
-static int nf_flow_tunnel_ip6ip6_push(struct net *net, struct sk_buff *skb,
-				      struct flow_offload_tuple *tuple,
-				      struct dst_entry *dst,
-				      struct in6_addr **ip6_daddr)
+static int nf_flow_tunnel_ip6_push(struct net *net, struct sk_buff *skb,
+				   struct flow_offload_tuple *tuple,
+				   struct dst_entry *dst,
+				   union nf_inet_addr **ip_addr)
 {
-	struct ipv6hdr *ip6h = (struct ipv6hdr *)skb_network_header(skb);
-	__u8 dsfield = ipv6_get_dsfield(ip6h);
-	struct rtable *rt = dst_rtable(dst);
 	struct flowi6 fl6 = {
 		.daddr = tuple->tun.src_v6,
 		.saddr = tuple->tun.dst_v6,
-		.flowi6_proto = IPPROTO_IPV6,
+		.flowi6_proto = tuple->tun.inner_proto,
 	};
-	u8 hop_limit = ip6h->hop_limit;
+	u8 hop_limit, dsfield;
+	struct ipv6hdr *ip6h;
 	int err, mtu;
 	u32 headroom;
 
+	switch (tuple->tun.inner_proto) {
+	case IPPROTO_IPIP: {
+		struct iphdr *iph = (struct iphdr *)skb_network_header(skb);
+
+		dsfield = ipv4_get_dsfield(iph);
+		hop_limit = iph->ttl;
+		break;
+	}
+	case IPPROTO_IPV6:
+		ip6h = (struct ipv6hdr *)skb_network_header(skb);
+		dsfield = ipv6_get_dsfield(ip6h);
+		hop_limit = ip6h->hop_limit;
+		break;
+	default:
+		return 0;
+	}
+
 	err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
 	if (err)
 		return err;
 
-	skb_set_inner_ipproto(skb, IPPROTO_IPV6);
-	headroom = sizeof(*ip6h) + LL_RESERVED_SPACE(rt->dst.dev) +
-		   rt->dst.header_len;
+	skb_set_inner_ipproto(skb, tuple->tun.inner_proto);
+	headroom = sizeof(*ip6h) + LL_RESERVED_SPACE(dst->dev) +
+		   dst->header_len;
 	err = skb_cow_head(skb, headroom);
 	if (err)
 		return err;
 
 	skb_scrub_packet(skb, true);
-	mtu = dst_mtu(&rt->dst) - sizeof(*ip6h);
+	mtu = dst_mtu(dst) - sizeof(*ip6h);
 	mtu = max(mtu, IPV6_MIN_MTU);
 	skb_dst_update_pmtu_no_confirm(skb, mtu);
 
 	skb_push(skb, sizeof(*ip6h));
 	skb_reset_network_header(skb);
+	skb->protocol = htons(ETH_P_IPV6);
 
 	ip6h = ipv6_hdr(skb);
 	ip6_flow_hdr(ip6h, dsfield,
 		     ip6_make_flowlabel(net, skb, fl6.flowlabel, true, &fl6));
 	ip6h->hop_limit = hop_limit;
-	ip6h->nexthdr = IPPROTO_IPV6;
+	ip6h->nexthdr = tuple->tun.inner_proto;
 	ip6h->daddr = tuple->tun.src_v6;
 	ip6h->saddr = tuple->tun.dst_v6;
 	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(*ip6h));
 	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
 
-	*ip6_daddr = &tuple->tun.src_v6;
+	*ip_addr = (union nf_inet_addr *)&tuple->tun.src_v6;
 
 	return 0;
 }
 
-static int nf_flow_tunnel_v6_push(struct net *net, struct sk_buff *skb,
-				  struct flow_offload_tuple *tuple,
-				  struct dst_entry *dst,
-				  struct in6_addr **ip6_daddr)
+static int nf_flow_tunnel_push(struct net *net, struct sk_buff *skb,
+			       struct flow_offload_tuple *tuple,
+			       struct dst_entry *dst,
+			       union nf_inet_addr **ip_addr)
 {
-	if (tuple->tun_num)
-		return nf_flow_tunnel_ip6ip6_push(net, skb, tuple, dst, ip6_daddr);
-
-	return 0;
+	switch (tuple->tun.encap_proto) {
+	case AF_INET:
+		return nf_flow_tunnel_ip_push(net, skb, tuple, dst, ip_addr);
+	case AF_INET6:
+		return nf_flow_tunnel_ip6_push(net, skb, tuple, dst, ip_addr);
+	default:
+		return 0;
+	}
 }
 
 static int nf_flow_encap_push(struct sk_buff *skb,
@@ -830,10 +862,10 @@ static int nf_flow_queue_xmit4(struct sk_buff *skb,
 	struct flow_offload_tuple *other_tuple;
 	enum flow_offload_tuple_dir dir;
 	struct nf_flow_xmit xmit = {};
+	union nf_inet_addr *ip_addr;
 	struct flow_offload *flow;
 	struct neighbour *neigh;
 	struct rtable *rt;
-	__be32 ip_daddr;
 
 	if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) {
 		rt = dst_rtable(tuplehash->tuple.dst_cache);
@@ -846,10 +878,10 @@ static int nf_flow_queue_xmit4(struct sk_buff *skb,
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 	other_tuple = &flow->tuplehash[!dir].tuple;
-	ip_daddr = other_tuple->src_v4.s_addr;
+	ip_addr = (union nf_inet_addr *)&other_tuple->src_v4;
 
-	if (nf_flow_tunnel_v4_push(state->net, skb, other_tuple,
-				   tuplehash->tuple.dst_cache, &ip_daddr) < 0)
+	if (nf_flow_tunnel_push(state->net, skb, other_tuple,
+				tuplehash->tuple.dst_cache, &ip_addr) < 0)
 		return NF_DROP;
 
 	switch (tuplehash->tuple.xmit_type) {
@@ -860,7 +892,7 @@ static int nf_flow_queue_xmit4(struct sk_buff *skb,
 			flow_offload_teardown(flow);
 			return NF_DROP;
 		}
-		neigh = ip_neigh_gw4(rt->dst.dev, rt_nexthop(rt, ip_daddr));
+		neigh = ip_neigh_gw4(rt->dst.dev, rt_nexthop(rt, ip_addr->ip));
 		if (IS_ERR(neigh)) {
 			flow_offload_teardown(flow);
 			return NF_DROP;
@@ -1154,7 +1186,7 @@ static int nf_flow_queue_xmit6(struct sk_buff *skb,
 	struct flow_offload_tuple *other_tuple;
 	enum flow_offload_tuple_dir dir;
 	struct nf_flow_xmit xmit = {};
-	struct in6_addr *ip6_daddr;
+	union nf_inet_addr *ip_addr;
 	struct flow_offload *flow;
 	struct neighbour *neigh;
 	struct rt6_info *rt;
@@ -1170,11 +1202,10 @@ static int nf_flow_queue_xmit6(struct sk_buff *skb,
 	dir = tuplehash->tuple.dir;
 	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 	other_tuple = &flow->tuplehash[!dir].tuple;
-	ip6_daddr = &other_tuple->src_v6;
+	ip_addr = (union nf_inet_addr *)&other_tuple->src_v6;
 
-	if (nf_flow_tunnel_v6_push(state->net, skb, other_tuple,
-				   tuplehash->tuple.dst_cache,
-				   &ip6_daddr) < 0)
+	if (nf_flow_tunnel_push(state->net, skb, other_tuple,
+				tuplehash->tuple.dst_cache, &ip_addr) < 0)
 		return NF_DROP;
 
 	switch (tuplehash->tuple.xmit_type) {
@@ -1185,7 +1216,7 @@ static int nf_flow_queue_xmit6(struct sk_buff *skb,
 			flow_offload_teardown(flow);
 			return NF_DROP;
 		}
-		neigh = ip_neigh_gw6(rt->dst.dev, rt6_nexthop(rt, ip6_daddr));
+		neigh = ip_neigh_gw6(rt->dst.dev, rt6_nexthop(rt, &ip_addr->in6));
 		if (IS_ERR(neigh)) {
 			flow_offload_teardown(flow);
 			return NF_DROP;
-- 
2.47.3

[PATCH net-next 08/15] selftests: netfilter: nft_queue.sh: only queue icmp echo request/reply

[Pablo Neira Ayuso]

From: Jakub Kicinski <kuba@kernel.org>

The bridge test flakes on debug kernels:

  FAIL: Expected 10 packets total, but got 24 packets total
  hook 3 packets 00000008
  hook 4 packets 00000010

The surplus are icmp fragment reassembly timeouts.  The udp flood in the
stress test leaves incomplete datagrams behind in ns2 and ns3, 30 seconds
later their reassembly queues expire and both namespaces send icmp time
exceeded to ns1's pre-bridge address.  ns3 is not reconfigured when the
router is turned into a bridge, so its messages arrive via veth2 and are
then forwarded out of br0. Such packets are locally originated from the
bridge point of view and are queued from the bridge output and
postrouting hooks, which is why only those two counters are off.

Restrict the ipv4 rule to echo request/reply, the icmpv6 rule already
does this.

We used to see 1 flake a day in NIPA before locally queuing this change,
zero flakes since (over 9 days)

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 tools/testing/selftests/net/netfilter/nft_queue.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/netfilter/nft_queue.sh b/tools/testing/selftests/net/netfilter/nft_queue.sh
index 7c857a2e0f34..c8d1f2eb4133 100755
--- a/tools/testing/selftests/net/netfilter/nft_queue.sh
+++ b/tools/testing/selftests/net/netfilter/nft_queue.sh
@@ -92,7 +92,7 @@ load_ruleset() {
 ip netns exec "$nsrouter" nft -f /dev/stdin <<EOF
 table $family $name {
 	chain nfq {
-		ip protocol icmp queue bypass
+		icmp type { "echo-request", "echo-reply" } queue bypass
 		icmpv6 type { "echo-request", "echo-reply" } queue num 1 bypass
 	}
 	chain pre {
-- 
2.47.3

[PATCH net-next 09/15] ipvs: fix buffer overflow when sending sync messages

[Pablo Neira Ayuso]

From: Julian Anastasov <ja@ssi.bg>

Sashiko reports for possible heap buffer overflow when
generating sync message for the v0 and v1 message formats.
We should read the cp->flags only once because another
CPU can concurrently set the SEQ_MASK between the two
reads.

Note that IPVS does not set the SEQ_MASK anymore for the
ip_vs_ftp.c helper starting from commit 7f1c40757951
("IPVS: make FTP work with full NAT support") (2.6.36+),
so the problem should not be reproducible.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Link: https://sashiko.dev/#/patchset/20260903004149.1037028-1-pablo%40netfilter.org
Link: https://sashiko.dev/#/patchset/20260909111338.44357-1-ja%40ssi.bg
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/ipvs/ip_vs_sync.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 45655cff078c..157f5c8361ab 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -543,13 +543,15 @@ static void ip_vs_sync_conn_v0(struct netns_ipvs *ipvs, struct ip_vs_conn *cp,
 	struct ip_vs_sync_conn_v0 *s;
 	struct ip_vs_sync_buff *buff;
 	struct ipvs_master_sync_state *ms;
-	int id;
+	u32 flags, seq_mask;
 	unsigned int len;
+	int id;
 
 	if (unlikely(cp->af != AF_INET))
 		return;
+	flags = READ_ONCE(cp->flags);
 	/* Do not sync ONE PACKET */
-	if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
+	if (flags & IP_VS_CONN_F_ONE_PACKET)
 		return;
 
 	if (!ip_vs_sync_conn_needed(ipvs, cp, pkts))
@@ -564,8 +566,8 @@ static void ip_vs_sync_conn_v0(struct netns_ipvs *ipvs, struct ip_vs_conn *cp,
 	id = select_master_thread_id(ipvs, cp);
 	ms = &ipvs->ms[id];
 	buff = ms->sync_buff;
-	len = (cp->flags & IP_VS_CONN_F_SEQ_MASK) ? FULL_CONN_SIZE :
-		SIMPLE_CONN_SIZE;
+	seq_mask = flags & IP_VS_CONN_F_SEQ_MASK;
+	len = seq_mask ? FULL_CONN_SIZE : SIMPLE_CONN_SIZE;
 	if (buff) {
 		m = (struct ip_vs_sync_mesg_v0 *) buff->mesg;
 		/* Send buffer if it is for v1 */
@@ -597,9 +599,9 @@ static void ip_vs_sync_conn_v0(struct netns_ipvs *ipvs, struct ip_vs_conn *cp,
 	s->caddr = cp->caddr.ip;
 	s->vaddr = cp->vaddr.ip;
 	s->daddr = cp->daddr.ip;
-	s->flags = htons(cp->flags & ~IP_VS_CONN_F_HASHED);
+	s->flags = htons(flags & ~IP_VS_CONN_F_HASHED);
 	s->state = htons(cp->state);
-	if (cp->flags & IP_VS_CONN_F_SEQ_MASK) {
+	if (seq_mask) {
 		struct ip_vs_sync_conn_options *opt =
 			(struct ip_vs_sync_conn_options *)&s[1];
 		memcpy(opt, &cp->sync_conn_opt, sizeof(*opt));
@@ -635,6 +637,7 @@ void ip_vs_sync_conn(struct netns_ipvs *ipvs, struct ip_vs_conn *cp, int pkts)
 	int id;
 	__u8 *p;
 	unsigned int len, pe_name_len, pad;
+	u32 flags, seq_mask;
 
 	/* Handle old version of the protocol */
 	if (sysctl_sync_ver(ipvs) == 0) {
@@ -647,6 +650,7 @@ void ip_vs_sync_conn(struct netns_ipvs *ipvs, struct ip_vs_conn *cp, int pkts)
 sloop:
 	if (!ip_vs_sync_conn_needed(ipvs, cp, pkts))
 		goto control;
+	flags = READ_ONCE(cp->flags);
 
 	/* Sanity checks */
 	pe_name_len = 0;
@@ -674,7 +678,8 @@ void ip_vs_sync_conn(struct netns_ipvs *ipvs, struct ip_vs_conn *cp, int pkts)
 #endif
 		len = sizeof(struct ip_vs_sync_v4);
 
-	if (cp->flags & IP_VS_CONN_F_SEQ_MASK)
+	seq_mask = flags & IP_VS_CONN_F_SEQ_MASK;
+	if (seq_mask)
 		len += sizeof(struct ip_vs_sync_conn_options) + 2;
 
 	if (cp->pe_data_len)
@@ -720,7 +725,7 @@ void ip_vs_sync_conn(struct netns_ipvs *ipvs, struct ip_vs_conn *cp, int pkts)
 	/* Set message type  & copy members */
 	s->v4.type = (cp->af == AF_INET6 ? STYPE_F_INET6 : 0);
 	s->v4.ver_size = htons(len & SVER_MASK);	/* Version 0 */
-	s->v4.flags = htonl(cp->flags & ~IP_VS_CONN_F_HASHED);
+	s->v4.flags = htonl(flags & ~IP_VS_CONN_F_HASHED);
 	s->v4.state = htons(cp->state);
 	s->v4.protocol = cp->protocol;
 	s->v4.cport = cp->cport;
@@ -744,7 +749,7 @@ void ip_vs_sync_conn(struct netns_ipvs *ipvs, struct ip_vs_conn *cp, int pkts)
 		s->v4.vaddr = cp->vaddr.ip;
 		s->v4.daddr = cp->daddr.ip;
 	}
-	if (cp->flags & IP_VS_CONN_F_SEQ_MASK) {
+	if (seq_mask) {
 		*(p++) = IPVS_OPT_SEQ_DATA;
 		*(p++) = sizeof(struct ip_vs_sync_conn_options);
 		hton_seq(&cp->in_seq, (struct ip_vs_seq *)p);
-- 
2.47.3

[PATCH net-next 10/15] netfilter: conntrack: fix unlikely UaF in gc worker

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

When early-drop scan is enabled, gc_worker() reads tmp->ct_net, resolves
cnet with nf_ct_pernet(), and reads cnet->count with RCU read lock held but
before acquiring a reference to tmp.

Its unlikely but possible that the worker gets preempted before reading
cnet->count while nf_conntrack_cleanup_net_list manages to unlink all
conntracks and returns in the mean time.
This allows for the pernet memory to get free'd.

On resume, use after free would occur when the worker reads cnet->count.

This can be solved either via another synchronize_rcu() in
nf_conntrack_cleanup_net_list or via cheaper flush_work().  If work
wasn't running no race can happen as next call cannot observe
already-unlinked conntrack objects.

This is an LLM finding with no reproducer, but it appears to be correct.

Fixes: c6dd940b1f74 ("netfilter: allow early drop of assured conntracks")
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_conntrack_core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index f9b8927327ba..4c4ca15dfd37 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -2506,6 +2506,11 @@ void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
 		goto i_see_dead_people;
 	}
 
+	/* must wait for current scan loop, worker also looks at
+	 * struct nf_conntrack_net, which is about to be free'd.
+	 */
+	flush_work(&conntrack_gc_work.dwork.work);
+
 	list_for_each_entry(net, net_exit_list, exit_list) {
 		warn_on_keymap_list_leak(net);
 		nf_conntrack_ecache_pernet_fini(net);
-- 
2.47.3

[PATCH net-next 11/15] netfilter: nf_tables: switch chain_types array to rcu

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

LLM quote:
 The global chain_type array is cleared under the nfnetlink subsystem
 mutex, but transaction processing reads it while holding only the pernet
 transaction mutex.
 nf_tables_chain_type_lookup() and nft_chain_parse_hook() dereference
 type->name/hook_mask before try_module_get(type->owner).

 Concurrent unloading of a separate provider such as nft_chain_nat can
 unregister and free its static nft_chain_type while a transaction is
 in the unprotected interval, causing a module-memory use-after-free.

LLM finding, not observed in practice.  Move this under RCU and grab the
module owner earlier.

Both nft_chain_route and nft_chain_filter are built into nf_tables.ko:
only nft_chain_nat needs an extra synchronize_rcu().

Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 94 ++++++++++++++++++++++++-----------
 net/netfilter/nft_chain_nat.c |  1 +
 2 files changed, 65 insertions(+), 30 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index b59628e6240c..59ac623e6805 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1036,32 +1036,67 @@ static inline u64 nf_tables_alloc_handle(struct nft_table *table)
 	return ++table->hgenerator;
 }
 
-static const struct nft_chain_type *chain_type[NFPROTO_NUMPROTO][NFT_CHAIN_T_MAX];
+static const struct nft_chain_type __rcu *chain_type[NFPROTO_NUMPROTO][NFT_CHAIN_T_MAX];
 
 static const struct nft_chain_type *
-__nft_chain_type_get(u8 family, enum nft_chain_types type)
+__nft_chain_type_peek(u8 family, enum nft_chain_types type)
 {
 	if (family >= NFPROTO_NUMPROTO ||
 	    type >= NFT_CHAIN_T_MAX)
 		return NULL;
 
-	return chain_type[family][type];
+	return rcu_dereference_check(chain_type[family][type],
+				     lockdep_nfnl_is_held(NFNL_SUBSYS_NFTABLES));
 }
 
+/**
+ * nft_chain_type_get - look up a chain type by family and id
+ * @family: netlink family
+ * @type:   chain type (enum nft_chain_types)
+ *
+ * Return: chain type with a held module ref, or NULL.
+ */
+static const struct nft_chain_type *
+nft_chain_type_get(u8 family, enum nft_chain_types type)
+{
+	const struct nft_chain_type *t;
+
+	rcu_read_lock();
+	t = __nft_chain_type_peek(family, type);
+
+	if (t && !try_module_get(t->owner))
+		t = NULL;
+
+	rcu_read_unlock();
+	return t;
+}
+
+/**
+ * __nf_tables_chain_type_lookup - look up a chain type by name
+ * @nla:    nlattr containing the chain-type name
+ * @family: netlink family
+ *
+ * Return: matching chain type with a held module ref, or NULL.
+ */
 static const struct nft_chain_type *
 __nf_tables_chain_type_lookup(const struct nlattr *nla, u8 family)
 {
-	const struct nft_chain_type *type;
+	const struct nft_chain_type *type = NULL, *t;
 	int i;
 
+	rcu_read_lock();
 	for (i = 0; i < NFT_CHAIN_T_MAX; i++) {
-		type = __nft_chain_type_get(family, i);
-		if (!type)
+		t = __nft_chain_type_peek(family, i);
+		if (!t)
 			continue;
-		if (!nla_strcmp(nla, type->name))
-			return type;
+
+		if (!nla_strcmp(nla, t->name) && try_module_get(t->owner)) {
+			type = t;
+			break;
+		}
 	}
-	return NULL;
+	rcu_read_unlock();
+	return type;
 }
 
 struct nft_module_request {
@@ -1837,11 +1872,11 @@ static void nf_tables_table_destroy(struct nft_table *table)
 void nft_register_chain_type(const struct nft_chain_type *ctype)
 {
 	nfnl_lock(NFNL_SUBSYS_NFTABLES);
-	if (WARN_ON(__nft_chain_type_get(ctype->family, ctype->type))) {
+	if (WARN_ON(__nft_chain_type_peek(ctype->family, ctype->type))) {
 		nfnl_unlock(NFNL_SUBSYS_NFTABLES);
 		return;
 	}
-	chain_type[ctype->family][ctype->type] = ctype;
+	rcu_assign_pointer(chain_type[ctype->family][ctype->type], ctype);
 	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
 }
 EXPORT_SYMBOL_GPL(nft_register_chain_type);
@@ -1849,7 +1884,7 @@ EXPORT_SYMBOL_GPL(nft_register_chain_type);
 void nft_unregister_chain_type(const struct nft_chain_type *ctype)
 {
 	nfnl_lock(NFNL_SUBSYS_NFTABLES);
-	chain_type[ctype->family][ctype->type] = NULL;
+	RCU_INIT_POINTER(chain_type[ctype->family][ctype->type], NULL);
 	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
 }
 EXPORT_SYMBOL_GPL(nft_unregister_chain_type);
@@ -2581,10 +2616,6 @@ static int nft_chain_parse_hook(struct net *net,
 		hook->num = ntohl(nla_get_be32(ha[NFTA_HOOK_HOOKNUM]));
 		hook->priority = ntohl(nla_get_be32(ha[NFTA_HOOK_PRIORITY]));
 
-		type = __nft_chain_type_get(family, NFT_CHAIN_T_DEFAULT);
-		if (!type)
-			return -EOPNOTSUPP;
-
 		if (nla[NFTA_CHAIN_TYPE]) {
 			type = nf_tables_chain_type_lookup(net, nla[NFTA_CHAIN_TYPE],
 							   family, true);
@@ -2592,13 +2623,19 @@ static int nft_chain_parse_hook(struct net *net,
 				NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_TYPE]);
 				return PTR_ERR(type);
 			}
+		} else {
+			type = nft_chain_type_get(family, NFT_CHAIN_T_DEFAULT);
+			if (!type)
+				return -EOPNOTSUPP;
 		}
+
+		err = -EOPNOTSUPP;
 		if (hook->num >= NFT_MAX_HOOKS || !(type->hook_mask & (1 << hook->num)))
-			return -EOPNOTSUPP;
+			goto out_put_type;
 
 		if (type->type == NFT_CHAIN_T_NAT &&
 		    hook->priority <= NF_IP_PRI_CONNTRACK)
-			return -EOPNOTSUPP;
+			goto out_put_type;
 	} else {
 		if (ha[NFTA_HOOK_HOOKNUM]) {
 			hook->num = ntohl(nla_get_be32(ha[NFTA_HOOK_HOOKNUM]));
@@ -2620,30 +2657,27 @@ static int nft_chain_parse_hook(struct net *net,
 			}
 		} else {
 			type = basechain->type;
+			__module_get(type->owner);
 		}
 	}
 
-	if (!try_module_get(type->owner)) {
-		if (nla[NFTA_CHAIN_TYPE])
-			NL_SET_BAD_ATTR(extack, nla[NFTA_CHAIN_TYPE]);
-		return -ENOENT;
-	}
-
 	hook->type = type;
 
 	INIT_LIST_HEAD(&hook->list);
 	if (nft_base_chain_netdev(family, hook->num)) {
 		err = nft_chain_parse_netdev(net, ha, &hook->list, extack, flags);
-		if (err < 0) {
-			module_put(type->owner);
-			return err;
-		}
+		if (err < 0)
+			goto out_put_type;
 	} else if (ha[NFTA_HOOK_DEV] || ha[NFTA_HOOK_DEVS]) {
-		module_put(type->owner);
-		return -EOPNOTSUPP;
+		err = -EOPNOTSUPP;
+		goto out_put_type;
 	}
 
 	return 0;
+
+out_put_type:
+	module_put(type->owner);
+	return err;
 }
 
 static void nft_chain_release_hook(struct nft_chain_hook *hook)
diff --git a/net/netfilter/nft_chain_nat.c b/net/netfilter/nft_chain_nat.c
index 40e230d8b712..1133f79d8d25 100644
--- a/net/netfilter/nft_chain_nat.c
+++ b/net/netfilter/nft_chain_nat.c
@@ -131,6 +131,7 @@ static void __exit nft_chain_nat_exit(void)
 #ifdef CONFIG_NF_TABLES_INET
 	nft_unregister_chain_type(&nft_chain_nat_inet);
 #endif
+	synchronize_rcu();
 }
 
 module_init(nft_chain_nat_init);
-- 
2.47.3

[PATCH net-next 12/15] netfilter: add nf_skb_sk helper and use it

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

nft and xt socket matching pass skb->sk to inet_sk_transparent().
On the LOCAL_OUT path an IP tunnel transmits while preserving the
original skb owner, so a non-INET socket (e.g. PF_PACKET) can reach
these code paths.  This is reachable for nft_socket.c which does allow
LOCAL_OUT. xt_socket only permits PREROUTING/LOCAL_IN.

nf_nat does this too, but there the inet_sk_transparent() call
is explicitly restricted to the INPUT hook.

For a packet socket the INET-specific offset lands inside the
packet statistics area.

Introduce nf_skb_sk() in nf_socket.h which returns skb->sk only when
it belongs to the given net namespace and passes sk_is_inet().

While at it, replace the `sk != skb->sk` refcount test with an
explicit refcounted flag that is set when the socket is obtained
via the lookup helper (the path that takes a reference).

LLM finding, no reproducer, no out-of-bounds memory access.

Assisted-by: LLM
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nf_socket.h | 20 ++++++++++++++++++++
 net/netfilter/nft_socket.c        | 16 +++++++++-------
 net/netfilter/xt_socket.c         | 26 ++++++++++++++------------
 3 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/include/net/netfilter/nf_socket.h b/include/net/netfilter/nf_socket.h
index f9d7bee9bd4e..39047c73b642 100644
--- a/include/net/netfilter/nf_socket.h
+++ b/include/net/netfilter/nf_socket.h
@@ -10,4 +10,24 @@ struct sock *nf_sk_lookup_slow_v4(struct net *net, const struct sk_buff *skb,
 struct sock *nf_sk_lookup_slow_v6(struct net *net, const struct sk_buff *skb,
 				  const struct net_device *indev);
 
+/**
+ * nf_skb_sk - Return the inet socket associated with an skb
+ * @skb: The skb to fetch sk from.
+ * @net: The network namespace the socket must belong to.
+ *
+ * On the output path, skb->sk may be non-INET when the skb is passing
+ * through an IP tunnel.
+ *
+ * Return:
+ * *sk* if it is an INET socket that belongs to @net, %NULL otherwise.
+ */
+static inline struct sock *nf_skb_sk(const struct sk_buff *skb, const struct net *net)
+{
+	struct sock *sk = skb->sk;
+
+	if (sk && net_eq(net, sock_net(sk)) && sk_is_inet(sk))
+		return sk;
+
+	return NULL;
+}
 #endif
diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index 52d892e04261..ea6c2f3dc3ff 100644
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -111,15 +111,17 @@ static void nft_socket_eval(const struct nft_expr *expr,
 			    const struct nft_pktinfo *pkt)
 {
 	const struct nft_socket *priv = nft_expr_priv(expr);
-	struct sk_buff *skb = pkt->skb;
-	struct sock *sk = skb->sk;
 	u32 *dest = &regs->data[priv->dreg];
+	struct sk_buff *skb = pkt->skb;
+	bool refcounted = false;
+	struct sock *sk;
 
-	if (sk && !net_eq(nft_net(pkt), sock_net(sk)))
-		sk = NULL;
-
-	if (!sk)
+	sk = nf_skb_sk(skb, nft_net(pkt));
+	if (!sk) {
 		sk = nft_socket_do_lookup(pkt);
+		if (sk)
+			refcounted = true;
+	}
 
 	if (!sk) {
 		regs->verdict.code = NFT_BREAK;
@@ -159,7 +161,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
 	}
 
 out_put_sk:
-	if (sk != skb->sk)
+	if (refcounted)
 		sock_gen_put(sk);
 }
 
diff --git a/net/netfilter/xt_socket.c b/net/netfilter/xt_socket.c
index 811e53bee408..cd3fc333ccf1 100644
--- a/net/netfilter/xt_socket.c
+++ b/net/netfilter/xt_socket.c
@@ -49,14 +49,15 @@ static bool
 socket_match(const struct sk_buff *skb, struct xt_action_param *par,
 	     const struct xt_socket_mtinfo1 *info)
 {
+	struct sock *sk = nf_skb_sk(skb, xt_net(par));
 	struct sk_buff *pskb = (struct sk_buff *)skb;
-	struct sock *sk = skb->sk;
+	bool refcounted = false;
 
-	if (sk && !net_eq(xt_net(par), sock_net(sk)))
-		sk = NULL;
-
-	if (!sk)
+	if (!sk) {
 		sk = nf_sk_lookup_slow_v4(xt_net(par), skb, xt_in(par));
+		if (sk)
+			refcounted = true;
+	}
 
 	if (sk) {
 		bool wildcard;
@@ -79,7 +80,7 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par,
 		    transparent && sk_fullsock(sk))
 			pskb->mark = READ_ONCE(sk->sk_mark);
 
-		if (sk != skb->sk)
+		if (refcounted)
 			sock_gen_put(sk);
 
 		if (wildcard || !transparent)
@@ -110,14 +111,15 @@ static bool
 socket_mt6_v1_v2_v3(const struct sk_buff *skb, struct xt_action_param *par)
 {
 	const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo;
+	struct sock *sk = nf_skb_sk(skb, xt_net(par));
 	struct sk_buff *pskb = (struct sk_buff *)skb;
-	struct sock *sk = skb->sk;
+	bool refcounted = false;
 
-	if (sk && !net_eq(xt_net(par), sock_net(sk)))
-		sk = NULL;
-
-	if (!sk)
+	if (!sk) {
 		sk = nf_sk_lookup_slow_v6(xt_net(par), skb, xt_in(par));
+		if (sk)
+			refcounted = true;
+	}
 
 	if (sk) {
 		bool wildcard;
@@ -140,7 +142,7 @@ socket_mt6_v1_v2_v3(const struct sk_buff *skb, struct xt_action_param *par)
 		    transparent && sk_fullsock(sk))
 			pskb->mark = READ_ONCE(sk->sk_mark);
 
-		if (sk != skb->sk)
+		if (refcounted)
 			sock_gen_put(sk);
 
 		if (wildcard || !transparent)
-- 
2.47.3

[PATCH net-next 13/15] netfilter: add nf_sk_to_full_sk helper and use it

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

Some callers of these helpers pass skb->sk as sk_partial argument, but
for LOCAL_OUT path an IP tunnel transmits while preserving the original
skb owner, so a non-INET socket (e.g. PF_PACKET) can reach these.

Like previous patch, add a helper to also check for this case.
Related to LLM finding in the earlier patch when querying the agent about
other possible scenarios.

Assisted-by: LLM
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nf_socket.h | 15 +++++++++++++++
 net/ipv4/netfilter.c              |  3 ++-
 net/ipv6/netfilter.c              |  3 ++-
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/net/netfilter/nf_socket.h b/include/net/netfilter/nf_socket.h
index 39047c73b642..f7da3dc150a9 100644
--- a/include/net/netfilter/nf_socket.h
+++ b/include/net/netfilter/nf_socket.h
@@ -3,6 +3,7 @@
 #define _NF_SOCK_H_
 
 #include <net/sock.h>
+#include <net/inet_sock.h>
 
 struct sock *nf_sk_lookup_slow_v4(struct net *net, const struct sk_buff *skb,
 				  const struct net_device *indev);
@@ -30,4 +31,18 @@ static inline struct sock *nf_skb_sk(const struct sk_buff *skb, const struct net
 
 	return NULL;
 }
+
+/**
+ * nf_sk_to_full_sk - Careful access to a full socket
+ * @sk: pointer to a socket
+ *
+ * %sk_to_full_sk for use when sk might not be an inet socket.
+ */
+static inline struct sock *nf_sk_to_full_sk(struct sock *sk)
+{
+	if (sk && sk_is_inet(sk))
+		return sk_to_full_sk(sk);
+
+	return NULL;
+}
 #endif
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index ce9e1bfa4259..76e1eb40b8ce 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -17,6 +17,7 @@
 #include <net/xfrm.h>
 #include <net/ip.h>
 #include <net/netfilter/nf_queue.h>
+#include <net/netfilter/nf_socket.h>
 
 /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
 int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, unsigned int addr_type)
@@ -30,7 +31,7 @@ int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, un
 	struct flow_keys flkeys;
 	unsigned int hh_len;
 
-	sk = sk_to_full_sk(sk);
+	sk = nf_sk_to_full_sk(sk);
 	flags = sk ? inet_sk_flowi_flags(sk) : 0;
 
 	if (addr_type == RTN_UNSPEC)
diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c
index a7025ec87035..70e47ccdf9ae 100644
--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -17,14 +17,15 @@
 #include <net/ip6_route.h>
 #include <net/xfrm.h>
 #include <net/netfilter/nf_queue.h>
+#include <net/netfilter/nf_socket.h>
 #include <net/netfilter/nf_conntrack_bridge.h>
 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
 #include "../bridge/br_private.h"
 
 int ip6_route_me_harder(struct net *net, struct sock *sk_partial, struct sk_buff *skb)
 {
+	struct sock *sk = nf_sk_to_full_sk(sk_partial);
 	const struct ipv6hdr *iph = ipv6_hdr(skb);
-	struct sock *sk = sk_to_full_sk(sk_partial);
 	struct net_device *dev = skb_dst_dev(skb);
 	struct flow_keys flkeys;
 	unsigned int hh_len;
-- 
2.47.3

[PATCH net-next 14/15] netfilter: nft_exthdr: remove redundant op parsing in tcp_set_init

[Pablo Neira Ayuso]

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

The nft_exthdr_tcp_set_init() function is exclusively used for TCP
options. Therefore, parsing the NFTA_EXTHDR_OP attribute from user
space is redundant, as the operation type must always be
NFT_EXTHDR_OP_TCPOPT.

Remove the unnecessary netlink attribute parsing and hardcode priv->op
to NFT_EXTHDR_OP_TCPOPT, which simplifies the code and reduces the
object size.

./scripts/bloat-o-meter exthdr_before.o exthdr_after.o
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-54 (-54)
Function                                     old     new   delta
nft_exthdr_tcp_set_init                      412     358     -54
Total: Before=6581, After=6527, chg -0.82%

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nft_exthdr.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 8abf8e8145ce..3492426dccf7 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -551,7 +551,7 @@ static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx,
 				   const struct nlattr * const tb[])
 {
 	struct nft_exthdr *priv = nft_expr_priv(expr);
-	u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
+	u32 offset, len, flags = 0;
 	int err;
 
 	if (!tb[NFTA_EXTHDR_SREG] ||
@@ -581,15 +581,11 @@ static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx,
 		return -EOPNOTSUPP;
 	}
 
-	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
-	if (err < 0)
-		return err;
-
 	priv->type   = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
 	priv->offset = offset;
 	priv->len    = len;
 	priv->flags  = flags;
-	priv->op     = op;
+	priv->op     = NFT_EXTHDR_OP_TCPOPT;
 
 	return nft_parse_register_load(ctx, tb[NFTA_EXTHDR_SREG], &priv->sreg,
 				       priv->len);
-- 
2.47.3

[PATCH net-next 15/15] netfilter: nft_exthdr: avoid 60 bytes stack buffer in TCP option mangling

[Pablo Neira Ayuso]

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

nft_exthdr_tcp_set_eval() and nft_exthdr_tcp_strip_eval() fetched the
TCP header and options through nft_tcp_header_pointer(), which calls
skb_header_pointer() a second time for the full tcphdr_len into a 60
bytes stack buffer. Since commit 28427f368f0e ("netfilter: nft_exthdr:
Fix non-linear header modification") both functions then call
skb_ensure_writable() and re-read the header from skb->data, so the
buffer was never used.

Only the 20 bytes fixed header is needed to learn tcphdr_len, so fetch
just that, validate the length as before, and let skb_ensure_writable()
pull the rest. This also drops the 60 bytes stack buffer from both
functions.

Comparison of performance in mpps:

  op       linear/non-linear     before    after    delta
==================================================================
   set,         non-linear       4.193     4.348    +3.7% mpps
   strip,       non-linear       4.184     4.434    +6.0% mpps
   set,         linear           5.302     5.427    +2.4% mpps
   strip,       linear           5.452     5.527    +1.4% mpss

Comparison of performance in ns/expression:

  op       linear/non-linear     before    after    delta
==================================================================
   set,         non-linear       34.6      25.3     -9.4  ns
   strip,       non-linear       35.2      20.8     -14.3 ns
   set,         linear           23.6      19.7     -3.9  ns
   strip,       linear           22.9      19.8     -3.1  ns

./scripts/bloat-o-meter exthdr_before.o exthdr_after.o
add/remove: 0/1 grow/shrink: 3/0 up/down: 233/-207 (26)
Function                                     old     new   delta
nft_exthdr_tcp_eval                          792     946    +154
nft_exthdr_tcp_strip_eval                    825     891     +66
nft_exthdr_tcp_set_eval                      602     615     +13
nft_tcp_header_pointer.part.constprop        207       -    -207
Total: Before=6527, After=6553, chg +0.40%

This also allow the compiler to inline nft_tcp_header_pointer inside
nft_exthdr_tcp_eval() which could yield some minimal performance gain.

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nft_exthdr.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 3492426dccf7..861bab93f435 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -233,16 +233,23 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
 				    struct nft_regs *regs,
 				    const struct nft_pktinfo *pkt)
 {
-	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
 	struct nft_exthdr *priv = nft_expr_priv(expr);
 	unsigned int i, optl, tcphdr_len, offset;
-	struct tcphdr *tcph;
+	struct tcphdr *tcph, _tcph;
 	u8 *opt;
 
-	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
+	if (pkt->tprot != IPPROTO_TCP || pkt->fragoff)
+		goto err;
+
+	tcph = skb_header_pointer(pkt->skb, nft_thoff(pkt), sizeof(_tcph), &_tcph);
 	if (!tcph)
 		goto err;
 
+	tcphdr_len = __tcp_hdrlen(tcph);
+	if (tcphdr_len < sizeof(*tcph) ||
+	    tcphdr_len > sizeof(*tcph) + MAX_TCP_OPTION_SPACE)
+		goto err;
+
 	if (skb_ensure_writable(pkt->skb, nft_thoff(pkt) + tcphdr_len))
 		goto err;
 
@@ -313,16 +320,23 @@ static void nft_exthdr_tcp_strip_eval(const struct nft_expr *expr,
 				      struct nft_regs *regs,
 				      const struct nft_pktinfo *pkt)
 {
-	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
 	struct nft_exthdr *priv = nft_expr_priv(expr);
 	unsigned int i, tcphdr_len, optl;
-	struct tcphdr *tcph;
+	struct tcphdr *tcph, _tcph;
 	u8 *opt;
 
-	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
+	if (pkt->tprot != IPPROTO_TCP || pkt->fragoff)
+		goto err;
+
+	tcph = skb_header_pointer(pkt->skb, nft_thoff(pkt), sizeof(_tcph), &_tcph);
 	if (!tcph)
 		goto err;
 
+	tcphdr_len = __tcp_hdrlen(tcph);
+	if (tcphdr_len < sizeof(*tcph) ||
+	    tcphdr_len > sizeof(*tcph) + MAX_TCP_OPTION_SPACE)
+		goto err;
+
 	if (skb_ensure_writable(pkt->skb, nft_thoff(pkt) + tcphdr_len))
 		goto drop;
 
-- 
2.47.3

Re: [PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[Pablo Neira Ayuso]

Hi,

+Cc: lorenzo@kernel.org

This is a report on sashiko's findings:

https://sashiko.dev/#/patchset/20261011215953.1334630-1-pablo%40netfilter.org

On Sun, Oct 11, 2026 at 11:59:38PM +0200, Pablo Neira Ayuso wrote:
> Hi,
> 
> The following patchset contains Netfilter/IPVS updates for net-next:
> 
> 1) Disable br_netfilter in userns and schedule it for removal in 2027,
>    from Florian Westphal.
> 
> 2) Prepare the flowtable to support for IPv4 over IPv6 tunneling and
>    vice-versa, this includes 5 patches from Lorenzo Bianconi.

I am afraid this preparation series is enabling more than it should,
sashiko reports type confusion is possible, for example:

  1/5 netfilter: flowtable: recognize IPv4/IPv6 in tunnel proto matching

this adds the initial pre-processing of IPv6-over-IPv4.

But then, nf_flow_offload_lookup() expects to handle IPv4, not an IPv6
packet.

I will repost this PR keeping them back.

> 3) Update selftest nft_queue.sh to make it more stable on debug
>    kernels, from Jakub Kicinski.
> 
> 4) Fix a overflow in IPVS sync messages which can only happen in very
>    old 2.6 kernels, from Julian Anastasov.
> 
> 5) Flush conntrack gc worker when existing netns to address a unlikely
>    UaF, from Florian Westphal.
> 
> 6) Switch nf_tables chain types to use rcu, otherwise module removal
>    can trigger UaF, also from Florian.
> 
> 7) Add two new helper functions to validate that socket is of inet type,
>    coming in 2 patches from Florian Westphal.

sashiko reports:

"If an IPv4 packet from an AF_INET socket is encapsulated by an IPv6 tunnel,
the tunnel preserves the AF_INET socket in skb->sk while transmitting the
outer IPv6 packet on the LOCAL_OUT path."

This sounds like an unrelated issue, I don't know yet how that can
happen TBH.

> 8) Remove redundant parsing in nft_exthdr for the tcp options case,
>    from Fernando F. Mancera.
> 
> 9) Remove redundant skb_header_pointer() calls in nft_exthdr for tcp
>    options, from Fernando F. Mancera.

Sashiko here reports this now drops malformed packets instead of
NFT_BREAK, which is fine, maybe just extend it to tell about this in
the patch description.

I plan to drop the flowtable preparation patches and resubmit.

> Please, pull these changes from:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git nf-next-26-10-11
> 
> Thanks.
> 
> ----------------------------------------------------------------
> 
> The following changes since commit a5e7d8e446af9803e37a3b6a4d416fb41178348f:
> 
>   Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue (2026-10-05 17:51:32 -0700)
> 
> are available in the Git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git nf-next-26-10-11
> 
> for you to fetch changes up to b4074bbf5c23b05bd34022ade979f3d5f4e86516:
> 
>   netfilter: nft_exthdr: avoid 60 bytes stack buffer in TCP option mangling (2026-10-11 23:29:26 +0200)
> 
> ----------------------------------------------------------------
> netfilter pull request 26-10-11
> 
> ----------------------------------------------------------------
> Fernando Fernandez Mancera (2):
>       netfilter: nft_exthdr: remove redundant op parsing in tcp_set_init
>       netfilter: nft_exthdr: avoid 60 bytes stack buffer in TCP option mangling
> 
> Florian Westphal (5):
>       netfilter: disable br_netfilter in user namespaces
>       netfilter: conntrack: fix unlikely UaF in gc worker
>       netfilter: nf_tables: switch chain_types array to rcu
>       netfilter: add nf_skb_sk helper and use it
>       netfilter: add nf_sk_to_full_sk helper and use it
> 
> Jakub Kicinski (1):
>       selftests: netfilter: nft_queue.sh: only queue icmp echo request/reply
> 
> Julian Anastasov (1):
>       ipvs: fix buffer overflow when sending sync messages
> 
> Lorenzo Bianconi (6):
>       netfilter: flowtable: recognize IPv4/IPv6 in tunnel proto matching
>       netfilter: flowtable: set inner protocol when popping tunnel header
>       netfilter: flowtable: populate tunnel tuple regardless of inner protocol
>       netfilter: flowtable: add encap_proto to flow_offload_tunnel
>       netfilter: flowtable: refactor MTU check for tunnel offload
>       netfilter: flowtable: unify tunnel push for IPv4 and IPv6
> 
>  Documentation/networking/bridge.rst                |   5 +-
>  include/linux/netdevice.h                          |   1 +
>  include/net/netfilter/nf_flow_table.h              |   1 +
>  include/net/netfilter/nf_socket.h                  |  35 ++++
>  net/bridge/br_netfilter_hooks.c                    |  33 +++-
>  net/ipv4/ipip.c                                    |   1 +
>  net/ipv4/netfilter.c                               |   3 +-
>  net/ipv6/ip6_tunnel.c                              |   1 +
>  net/ipv6/netfilter.c                               |   3 +-
>  net/netfilter/ipvs/ip_vs_sync.c                    |  23 ++-
>  net/netfilter/nf_conntrack_core.c                  |   5 +
>  net/netfilter/nf_flow_table_ip.c                   | 215 +++++++++++++--------
>  net/netfilter/nf_flow_table_path.c                 |   2 +
>  net/netfilter/nf_tables_api.c                      |  94 ++++++---
>  net/netfilter/nft_chain_nat.c                      |   1 +
>  net/netfilter/nft_exthdr.c                         |  34 ++--
>  net/netfilter/nft_socket.c                         |  16 +-
>  net/netfilter/xt_socket.c                          |  26 +--
>  tools/testing/selftests/net/netfilter/nft_queue.sh |   2 +-
>  19 files changed, 336 insertions(+), 165 deletions(-)
> 

Re: [PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[Florian Westphal]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> sashiko reports:
> 
> "If an IPv4 packet from an AF_INET socket is encapsulated by an IPv6 tunnel,
> the tunnel preserves the AF_INET socket in skb->sk while transmitting the
> outer IPv6 packet on the LOCAL_OUT path."
> 
> This sounds like an unrelated issue, I don't know yet how that can
> happen TBH.

I'm stupid and I don't understand why this would be a regression.

This change makes things stricter, so it doesn't enable anything that
wasn't allowed before, how does this add a new crash regression? :-(

Re: [PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[Florian Westphal]

Florian Westphal <fw@strlen.de> wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > sashiko reports:
> > 
> > "If an IPv4 packet from an AF_INET socket is encapsulated by an IPv6 tunnel,
> > the tunnel preserves the AF_INET socket in skb->sk while transmitting the
> > outer IPv6 packet on the LOCAL_OUT path."
> > 
> > This sounds like an unrelated issue, I don't know yet how that can
> > happen TBH.
> 
> I'm stupid and I don't understand why this would be a regression.
> 
> This change makes things stricter, so it doesn't enable anything that
> wasn't allowed before, how does this add a new crash regression? :-(

Please toss this patch. Lets ignore this problem.

Re: [PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[Pablo Neira Ayuso]

On Wed, Oct 14, 2026 at 01:23:46PM +0200, Florian Westphal wrote:
> Florian Westphal <fw@strlen.de> wrote:
> > Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > > sashiko reports:
> > > 
> > > "If an IPv4 packet from an AF_INET socket is encapsulated by an IPv6 tunnel,
> > > the tunnel preserves the AF_INET socket in skb->sk while transmitting the
> > > outer IPv6 packet on the LOCAL_OUT path."
> > > 
> > > This sounds like an unrelated issue, I don't know yet how that can
> > > happen TBH.
> > 
> > I'm stupid and I don't understand why this would be a regression.
> > 
> > This change makes things stricter, so it doesn't enable anything that
> > wasn't allowed before, how does this add a new crash regression? :-(
> 
> Please toss this patch. Lets ignore this problem.

I really think LLM is just getting confused, because the series
contains flowtable support for IPv4-over-IPv6 and vice-versa.

Then, the LLM tries to find the same pattern in the patches coming in
this PR batch !:-D

[PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[Pablo Neira Ayuso]

Hi,

The following patchset contains Netfilter/IPVS updates for net-next,
this contains updates to address sashiko reports in IPVS and Netfilter
on possible pre-existing issues. This also includes a series to add
refcount for ct helper and timeout to deal with a corner case scenario
with unconfirmed conntracks flying to nfqueue.

1) Add a conn_max sysctl to IPVS to limit the maximum number of
   connections, from Julian Anastasov.

2) Use get_unaligned_be16() to access TCP MSS in nfnetlink_osf,
   from Fernando Fernandez Mancera.

3) Use {READ,WRITE}_ONCE to access helper flags from nfnetlink_helper.

Several patches for the synproxy infrastructure, from Fernando
Fernandez Mancera:

4) Drop packet if TCP timestamp adjustment fails.

5) Continue parsing of TCP timestamp to deal with possible duplicates.

6) Use {get,put}_unaligned_be32() to acess the TCP timestamp.

7) Hold ct->lock to initialize nf_ct_seqadj_init().

Updates for the ct timeout infrastructure, to deal with a corner case
for unconfirmed conntracks flying to nfqueue:

8) Add a refcount to track ct timeout policy use by ct extension,
   release the timeout until the last ct extension drops the refcnt
   on it.

Similar update for the ct helper infrastructure:

9) Dynamic allocation of ct helpers, as a preparation for adding
   refcount to track ct extension use.

10) Move destroy_sibling_or_exp() to nf_conntrack_proto_gre, so
    pptp conntrack helper module removal does not make this code
    unreachable via the helper->destroy callback. This is another
    dependency for the new refcount coming in this series.

11) Add a refcount to track use of it from the ct extension, then
    ct helper and timeout is reachable to the connection until
    it goes away.

12) Remove the genid infrastructure in ct extensions. The primary
    goal was to detect that a ct extension such as ct timeout and
    ct helper went stale for unconfirmed conntrack, either because
    object or module was removed. This deactivates all ct extensions
    though for this unconfirmed conntrack.

13) Call nf_ct_gre_keymap_destroy() if this is a master conntrack
    with a pptp helper only.

sashiko.dev reports one more relevant issue when unsetting the helper
via ctnetlink that I will address in a follow up patch.

Then, two more assorted updates:

14) Avoid a unlikely underflow in bridge VLAN untag, only possible
    if buggy bridge VLAN filtering is buggy, remove WARN_ON_ONCE
    while at it. From David Carlier.

15) Use get_unaligned_be32() in nf_conntrack_tcp to access sack
    extension, from Rosen Penev.

Please, pull these changes from:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git nf-next-26-06-07

Thanks.

----------------------------------------------------------------

The following changes since commit bfa3d89cc15c09f7d1581c834a5ed725189ec19f:

  Merge tag 'batadv-next-pullrequest-20260603' of https://git.open-mesh.org/batadv (2026-06-04 19:14:35 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git tags/nf-next-26-06-07

for you to fetch changes up to d3bf9eae486490832bd08fd62ab0ac601f346bd4:

  netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack() (2026-06-07 11:13:47 +0200)

----------------------------------------------------------------
netfilter pull request 26-06-07

----------------------------------------------------------------
David Carlier (1):
      netfilter: flowtable: avoid num_encaps underflow on bridge VLAN untag

Fernando Fernandez Mancera (5):
      netfilter: nfnetlink_osf: fix mss parsing on big-endian architectures
      netfilter: synproxy: drop packets if timestamp adjustment fails
      netfilter: synproxy: adjust duplicate timestamp options
      netfilter: synproxy: fix unaligned memory access in timestamp adjustment
      netfilter: synproxy: protect nf_ct_seqadj_init() with conntrack lock

Julian Anastasov (1):
      ipvs: add conn_max sysctl to limit connections

Pablo Neira Ayuso (7):
      netfilter: nfnetlink_cthelper: use {READ,WRITE}_ONCE for accessing helper flags
      netfilter: cttimeout: detach dataplane timeout policy and repurpose refcount
      netfilter: nf_conntrack_helper: dynamically allocate struct nf_conntrack_helper
      netfilter: nf_conntrack_pptp: move GRE specific cleanup to GRE tracker
      netfilter: nf_conntrack_helper: add refcounting from datapath
      netfilter: conntrack: revert ct extension genid infrastructure
      netfilter: conntrack: call nf_ct_gre_keymap_destroy() if master helper is pptp

Rosen Penev (1):
      netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()

 Documentation/networking/ipvs-sysctl.rst       |  35 +++++++
 include/net/ip_vs.h                            |  22 +++++
 include/net/netfilter/ipv4/nf_conntrack_ipv4.h |   4 +
 include/net/netfilter/nf_conntrack_extend.h    |  12 ---
 include/net/netfilter/nf_conntrack_helper.h    |  42 ++++++---
 include/net/netfilter/nf_conntrack_timeout.h   |  27 +++++-
 net/ipv4/netfilter/nf_nat_snmp_basic_main.c    |  27 +++---
 net/netfilter/ipvs/ip_vs_conn.c                |  10 +-
 net/netfilter/ipvs/ip_vs_ctl.c                 |  53 +++++++++++
 net/netfilter/nf_conntrack_amanda.c            |  39 +++-----
 net/netfilter/nf_conntrack_core.c              |  92 +++++-------------
 net/netfilter/nf_conntrack_extend.c            |  32 +------
 net/netfilter/nf_conntrack_ftp.c               |   5 +-
 net/netfilter/nf_conntrack_h323_main.c         | 107 +++++++++------------
 net/netfilter/nf_conntrack_helper.c            | 125 +++++++++++++++++--------
 net/netfilter/nf_conntrack_irc.c               |   5 +-
 net/netfilter/nf_conntrack_netbios_ns.c        |  20 ++--
 net/netfilter/nf_conntrack_netlink.c           |  28 ++++--
 net/netfilter/nf_conntrack_ovs.c               |   9 +-
 net/netfilter/nf_conntrack_pptp.c              |  83 +++-------------
 net/netfilter/nf_conntrack_proto.c             |  15 ++-
 net/netfilter/nf_conntrack_proto_gre.c         |  61 ++++++++++++
 net/netfilter/nf_conntrack_proto_tcp.c         |  10 +-
 net/netfilter/nf_conntrack_sane.c              |   5 +-
 net/netfilter/nf_conntrack_seqadj.c            |   2 +
 net/netfilter/nf_conntrack_sip.c               |   5 +-
 net/netfilter/nf_conntrack_snmp.c              |  21 ++---
 net/netfilter/nf_conntrack_tftp.c              |   5 +-
 net/netfilter/nf_conntrack_timeout.c           |  27 +++++-
 net/netfilter/nf_flow_table_path.c             |   3 +-
 net/netfilter/nf_synproxy_core.c               |  40 ++++----
 net/netfilter/nfnetlink_cthelper.c             |  79 ++++++++--------
 net/netfilter/nfnetlink_cttimeout.c            | 112 ++++++++++------------
 net/netfilter/nfnetlink_osf.c                  |   6 +-
 net/netfilter/nft_ct.c                         |  10 +-
 net/netfilter/xt_CT.c                          |   3 -
 36 files changed, 653 insertions(+), 528 deletions(-)

Re: [PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[Pablo Neira Ayuso]

Hi,

I'm replying to Sashiko.dev comments here:

* [PATCH net-next 06/15] netfilter: synproxy: fix unaligned memory access in timestamp adjustment

Refers to pre-existing issue. I think this comment is not correct?

* [PATCH net-next 07/15] netfilter: synproxy: protect nf_ct_seqadj_init() with conntrack lock

Refers to pre-existing issue. But I think it is not correct, reopened
connections in TIME_WAIT are killed by TCP protocol tracker, so they
start in a clean state.

It also suggests check for NULL in seqadj = nfct_seqadj(ct); this is
related to a bug in the ct extension generation ID which is addressed
by this batch. Anyway, Florian and me agreed that adding this NULL
check for safety is good to go, and I have a patch fot this.

* [PATCH net-next 08/15] netfilter: cttimeout: detach dataplane timeout policy and repurpose refcount

Wrong comment by AI. 

> Does removing this assignment cause nftables ct timeout rules to silently fail
> if a timeout extension is already present?

The ct timeout is only applied to a new conntrack that unconfirmed,
this override semantics does not make sense to me.

* [PATCH net-next 11/15] netfilter: nf_conntrack_helper: add refcounting from datapath

Refer to pre-existing issue. Yes, ->destroy() is missing here and in
ctnetlink, I will post a patch to address this. This also refer to
ctnetlink_change_helper().

* [PATCH net-next 13/15] netfilter: conntrack: call nf_ct_gre_keymap_destroy() if master helper is pptp

No other helper support the .destroy callback. AI assumes other
helpers support this callback.

* [PATCH net-next 14/15] netfilter: flowtable: avoid num_encaps underflow on bridge VLAN untag

Refers to pre-existing issue. Yes, this function nft_dev_path_info()
can be made more robust when failing to build a fast path. I have a
follow up patch for this.

There is another issue with the IPVS patch that adds the conn_max
documentation (incorrect format), Julian Anastasov is ready to send a
follow up patch address it.

Let me know, thanks.

On Sun, Jun 07, 2026 at 11:49:39AM +0200, Pablo Neira Ayuso wrote:
> Hi,
> 
> The following patchset contains Netfilter/IPVS updates for net-next,
> this contains updates to address sashiko reports in IPVS and Netfilter
> on possible pre-existing issues. This also includes a series to add
> refcount for ct helper and timeout to deal with a corner case scenario
> with unconfirmed conntracks flying to nfqueue.
> 
> 1) Add a conn_max sysctl to IPVS to limit the maximum number of
>    connections, from Julian Anastasov.
> 
> 2) Use get_unaligned_be16() to access TCP MSS in nfnetlink_osf,
>    from Fernando Fernandez Mancera.
> 
> 3) Use {READ,WRITE}_ONCE to access helper flags from nfnetlink_helper.
> 
> Several patches for the synproxy infrastructure, from Fernando
> Fernandez Mancera:
> 
> 4) Drop packet if TCP timestamp adjustment fails.
> 
> 5) Continue parsing of TCP timestamp to deal with possible duplicates.
> 
> 6) Use {get,put}_unaligned_be32() to acess the TCP timestamp.
> 
> 7) Hold ct->lock to initialize nf_ct_seqadj_init().
> 
> Updates for the ct timeout infrastructure, to deal with a corner case
> for unconfirmed conntracks flying to nfqueue:
> 
> 8) Add a refcount to track ct timeout policy use by ct extension,
>    release the timeout until the last ct extension drops the refcnt
>    on it.
> 
> Similar update for the ct helper infrastructure:
> 
> 9) Dynamic allocation of ct helpers, as a preparation for adding
>    refcount to track ct extension use.
> 
> 10) Move destroy_sibling_or_exp() to nf_conntrack_proto_gre, so
>     pptp conntrack helper module removal does not make this code
>     unreachable via the helper->destroy callback. This is another
>     dependency for the new refcount coming in this series.
> 
> 11) Add a refcount to track use of it from the ct extension, then
>     ct helper and timeout is reachable to the connection until
>     it goes away.
> 
> 12) Remove the genid infrastructure in ct extensions. The primary
>     goal was to detect that a ct extension such as ct timeout and
>     ct helper went stale for unconfirmed conntrack, either because
>     object or module was removed. This deactivates all ct extensions
>     though for this unconfirmed conntrack.
> 
> 13) Call nf_ct_gre_keymap_destroy() if this is a master conntrack
>     with a pptp helper only.
> 
> sashiko.dev reports one more relevant issue when unsetting the helper
> via ctnetlink that I will address in a follow up patch.
> 
> Then, two more assorted updates:
> 
> 14) Avoid a unlikely underflow in bridge VLAN untag, only possible
>     if buggy bridge VLAN filtering is buggy, remove WARN_ON_ONCE
>     while at it. From David Carlier.
> 
> 15) Use get_unaligned_be32() in nf_conntrack_tcp to access sack
>     extension, from Rosen Penev.
> 
> Please, pull these changes from:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git nf-next-26-06-07
> 
> Thanks.
> 
> ----------------------------------------------------------------
> 
> The following changes since commit bfa3d89cc15c09f7d1581c834a5ed725189ec19f:
> 
>   Merge tag 'batadv-next-pullrequest-20260603' of https://git.open-mesh.org/batadv (2026-06-04 19:14:35 -0700)
> 
> are available in the Git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git tags/nf-next-26-06-07
> 
> for you to fetch changes up to d3bf9eae486490832bd08fd62ab0ac601f346bd4:
> 
>   netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack() (2026-06-07 11:13:47 +0200)
> 
> ----------------------------------------------------------------
> netfilter pull request 26-06-07
> 
> ----------------------------------------------------------------
> David Carlier (1):
>       netfilter: flowtable: avoid num_encaps underflow on bridge VLAN untag
> 
> Fernando Fernandez Mancera (5):
>       netfilter: nfnetlink_osf: fix mss parsing on big-endian architectures
>       netfilter: synproxy: drop packets if timestamp adjustment fails
>       netfilter: synproxy: adjust duplicate timestamp options
>       netfilter: synproxy: fix unaligned memory access in timestamp adjustment
>       netfilter: synproxy: protect nf_ct_seqadj_init() with conntrack lock
> 
> Julian Anastasov (1):
>       ipvs: add conn_max sysctl to limit connections
> 
> Pablo Neira Ayuso (7):
>       netfilter: nfnetlink_cthelper: use {READ,WRITE}_ONCE for accessing helper flags
>       netfilter: cttimeout: detach dataplane timeout policy and repurpose refcount
>       netfilter: nf_conntrack_helper: dynamically allocate struct nf_conntrack_helper
>       netfilter: nf_conntrack_pptp: move GRE specific cleanup to GRE tracker
>       netfilter: nf_conntrack_helper: add refcounting from datapath
>       netfilter: conntrack: revert ct extension genid infrastructure
>       netfilter: conntrack: call nf_ct_gre_keymap_destroy() if master helper is pptp
> 
> Rosen Penev (1):
>       netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack()
> 
>  Documentation/networking/ipvs-sysctl.rst       |  35 +++++++
>  include/net/ip_vs.h                            |  22 +++++
>  include/net/netfilter/ipv4/nf_conntrack_ipv4.h |   4 +
>  include/net/netfilter/nf_conntrack_extend.h    |  12 ---
>  include/net/netfilter/nf_conntrack_helper.h    |  42 ++++++---
>  include/net/netfilter/nf_conntrack_timeout.h   |  27 +++++-
>  net/ipv4/netfilter/nf_nat_snmp_basic_main.c    |  27 +++---
>  net/netfilter/ipvs/ip_vs_conn.c                |  10 +-
>  net/netfilter/ipvs/ip_vs_ctl.c                 |  53 +++++++++++
>  net/netfilter/nf_conntrack_amanda.c            |  39 +++-----
>  net/netfilter/nf_conntrack_core.c              |  92 +++++-------------
>  net/netfilter/nf_conntrack_extend.c            |  32 +------
>  net/netfilter/nf_conntrack_ftp.c               |   5 +-
>  net/netfilter/nf_conntrack_h323_main.c         | 107 +++++++++------------
>  net/netfilter/nf_conntrack_helper.c            | 125 +++++++++++++++++--------
>  net/netfilter/nf_conntrack_irc.c               |   5 +-
>  net/netfilter/nf_conntrack_netbios_ns.c        |  20 ++--
>  net/netfilter/nf_conntrack_netlink.c           |  28 ++++--
>  net/netfilter/nf_conntrack_ovs.c               |   9 +-
>  net/netfilter/nf_conntrack_pptp.c              |  83 +++-------------
>  net/netfilter/nf_conntrack_proto.c             |  15 ++-
>  net/netfilter/nf_conntrack_proto_gre.c         |  61 ++++++++++++
>  net/netfilter/nf_conntrack_proto_tcp.c         |  10 +-
>  net/netfilter/nf_conntrack_sane.c              |   5 +-
>  net/netfilter/nf_conntrack_seqadj.c            |   2 +
>  net/netfilter/nf_conntrack_sip.c               |   5 +-
>  net/netfilter/nf_conntrack_snmp.c              |  21 ++---
>  net/netfilter/nf_conntrack_tftp.c              |   5 +-
>  net/netfilter/nf_conntrack_timeout.c           |  27 +++++-
>  net/netfilter/nf_flow_table_path.c             |   3 +-
>  net/netfilter/nf_synproxy_core.c               |  40 ++++----
>  net/netfilter/nfnetlink_cthelper.c             |  79 ++++++++--------
>  net/netfilter/nfnetlink_cttimeout.c            | 112 ++++++++++------------
>  net/netfilter/nfnetlink_osf.c                  |   6 +-
>  net/netfilter/nft_ct.c                         |  10 +-
>  net/netfilter/xt_CT.c                          |   3 -
>  36 files changed, 653 insertions(+), 528 deletions(-)
> 

Re: [PATCH net-next 00/15] Netfilter/IPVS updates for net-next

[Pablo Neira Ayuso]

Hi,

On Mon, Jun 08, 2026 at 01:58:40PM +0200, Pablo Neira Ayuso wrote:
> Hi,
> 
> I'm replying to Sashiko.dev comments here:
> 
> * [PATCH net-next 06/15] netfilter: synproxy: fix unaligned memory access in timestamp adjustment
> 
> Refers to pre-existing issue. I think this comment is not correct?

Yes, it is, inet_proto_csum_replace4() needs an even offset to the
16-bit word. Checksum will be corrupted, but at least the alignment
issue is addressed, which leaves things better than before. Maybe
it is worth to add a note to this patch.

I can post a v2 of this PR to refine the few things that make sense at
this stage.