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

[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 00/15] Netfilter 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) Update selftest nft_queue.sh to make it more stable on debug
   kernels, from Jakub Kicinski.

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

4) Finer grain packet drop in nfnetlink_queue when dependency objects
   are going away, from Antonio Ojea.

5) Add a selftest for the nfnetlink_queue packet drop case, also
   from Antonio Ojea.

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

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

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.

10) Fix conntrack_vrf.sh selftest return value in zone subtest,
    from Florian Westphal.

11) Restrict raw table in nft_compat to specific family, hook and
    priority, from Florian Westphal.

Prepare the flowtable to support for IPv4 over IPv6 tunneling and
vice-versa, this includes 4 patches from Lorenzo Bianconi.

12) Explicitly set inner protocol when popping header, this is not
    needed for the existing IPIP and IP6IP6 case because skb->protocol
    remains the same.

13) Simplify tuple tunnel information fill up when parsing outer
    tunnel IP headers.
    
14) Add a new encap_proto which determines the outer tunnel protocol
    family.

15) Prepare flowtable forwarding path to deal with mixed IPv4-IPv6
    tunnels.

Please, pull these changes from:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next.git nf-next-26-10-18

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-26-10-18

for you to fetch changes up to d0107f38162279d9cb0e012210731176265f835d:

  netfilter: flowtable: unify tunnel push for IPv4 and IPv6 (2026-10-18 02:42:04 +0200)

----------------------------------------------------------------
netfilter pull request 26-10-18

----------------------------------------------------------------
Antonio Ojea (2):
      netfilter: nf_queue: limit the hook drop flush to the unregistered hook point
      selftests: netfilter: nft_queue: check the scope of the hook drop flush

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
      selftests: netfilter: fix return value in zone subtest
      netfilter: nft_compat: restrict raw table targets/matches

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 (4):
      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: 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_queue.h                   |   3 +-
 net/bridge/br_netfilter_hooks.c                    |  33 ++--
 net/ipv4/ipip.c                                    |   1 +
 net/ipv6/ip6_tunnel.c                              |   1 +
 net/netfilter/core.c                               |   2 +-
 net/netfilter/ipvs/ip_vs_sync.c                    |  23 +--
 net/netfilter/nf_conntrack_core.c                  |   7 +-
 net/netfilter/nf_flow_table_ip.c                   | 170 +++++++++++++--------
 net/netfilter/nf_flow_table_path.c                 |   2 +
 net/netfilter/nf_internals.h                       |   2 +-
 net/netfilter/nf_queue.c                           |   4 +-
 net/netfilter/nf_tables_api.c                      |  94 ++++++++----
 net/netfilter/nfnetlink_queue.c                    |  41 ++++-
 net/netfilter/nft_chain_nat.c                      |   1 +
 net/netfilter/nft_compat.c                         |  15 ++
 net/netfilter/nft_ct.c                             |   2 +-
 net/netfilter/nft_exthdr.c                         |  34 +++--
 .../selftests/net/netfilter/conntrack_vrf.sh       |  25 ++-
 tools/testing/selftests/net/netfilter/nf_queue.c   |  22 ++-
 tools/testing/selftests/net/netfilter/nft_queue.sh | 110 ++++++++++++-
 23 files changed, 456 insertions(+), 143 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] 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 03/15] 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 04/15] netfilter: nf_queue: limit the hook drop flush to the unregistered hook point

[Pablo Neira Ayuso]

From: Antonio Ojea <aojea@google.com>

Unregistering a netfilter hook calls nf_queue_nf_hook_drop(), which makes
nfqnl_nf_hook_drop() walk every nfqueue instance of the network namespace
and flush it, reinjecting every packet that waits for a verdict with
NF_DROP. Deleting an nftables base chain of any table, family and hook
point therefore drops the packets queued by hooks of unrelated tables,
families and hook points. The verdict that userspace sends for them
afterwards fails with -ENOENT.

Before commit 039b40ee5854 ("netfilter: nf_queue: only call
synchronize_net twice if nf_queue is active") nf_queue_nf_hook_drop()
received the removed hook and nfqueue only dropped the entries queued by
that hook. The commit removed the argument and the comparison because
base chain removal while nfqueue is in use was rare at the time. With
base chains added and removed by userspace agents while another program
holds packets in a queue this is no longer the case. Commit
960632ece694 ("netfilter: convert hook list to an array") then replaced
the hook pointer in struct nf_queue_entry with an index into the hook
array of the hook point, so a comparison per hook is no longer possible.
A comparison per hook point is: the index of an entry is only stale when
the array of its own hook point changed.

Pass the nf_hook_ops being unregistered down to the queue handler and
add nf_hook_cmp() to nfnetlink_queue, a cmpfn for nfqnl_flush() that
matches the entries whose state.pf and state.hook are the hook point of
that hook. The handler takes the nf_hook_ops rather than the family of
the modified array to keep a single argument with NULL meaning "flush
everything", which nf_ct_iterate_destroy() uses on module exit and
__nft_ct_set_destroy() uses when a ct zone expression goes away and a
queued packet may still reference its conntrack template. The
cmpfn resolves the family itself. An NFPROTO_INET hook is registered in
the IPv4 and the IPv6 array, so it matches the entries of both families;
nf_unregister_net_hook() calls __nf_unregister_net_hook() for the two
arrays back to back and the second flush finds nothing left. If the
shrink of one array fails to allocate, that array keeps its dummy hook
and its entries stay valid, so the flush for the other family drops
them without need; no entry with a stale index survives. An
NFPROTO_INET hook at NF_INET_INGRESS is registered in the netdev ingress
array, the same mapping that nf_static_key_inc() applies. nfqueue does
not accept the ingress and egress hooks (nft_queue_validate()), the
mapping keeps the comparison consistent with the registration.

The entries queued from the hook point whose array changed are still
dropped, their hook_index is stale. Registering a hook in front of the
one that queued a packet still makes nf_reinject() resume at a stale
index, so the packet traverses the queueing hook a second time; this is
not changed here.

Tested with the reproducer script from the thread, unchanged: it queues
20 UDP packets from an inet output chain to a queue program that delays
every verdict by 100 ms and changes the ruleset while they wait. Before
this change deleting an unrelated ip6 base chain or an unrelated ip6
table delivers 3 of 20 packets and the queue program exits on ENOENT;
with it all 20 are delivered. Deleting a base chain at the same hook
point (inet output, another priority, in the same or another table) or
an ip table with an output base chain still drops the queued packets;
deleting an ip6 table with an output base chain or a netdev ingress
chain does not. Adding a base chain in front of the queueing one still
queues the packets twice. The nft_queue.sh selftest passes, with
CONFIG_NETFILTER_NETLINK_QUEUE=y and built as a module. The following
patch adds a test for both outcomes that holds the verdicts instead of
delaying them.

The code and this commit message were written with an LLM coding
assistant from a task description that contained the report, the
suggestion from the thread and the two commits above. The author
reviewed the result, directed the changes and validated them with the
reproducer and the selftest in virtme-ng before and after the change.

Suggested-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/netfilter-devel/CABhP=tYtCyr-qzL==98nkmDVZr6x+f8E26V1AAOpMXgZgt0vAQ@mail.gmail.com/
Assisted-by: LLM
Signed-off-by: Antonio Ojea <aojea@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nf_queue.h  |  3 ++-
 net/netfilter/core.c              |  2 +-
 net/netfilter/nf_conntrack_core.c |  2 +-
 net/netfilter/nf_internals.h      |  2 +-
 net/netfilter/nf_queue.c          |  4 +--
 net/netfilter/nfnetlink_queue.c   | 41 +++++++++++++++++++++++++++++--
 net/netfilter/nft_ct.c            |  2 +-
 7 files changed, 47 insertions(+), 9 deletions(-)

diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h
index fc3e81c07364..86021c55ba3c 100644
--- a/include/net/netfilter/nf_queue.h
+++ b/include/net/netfilter/nf_queue.h
@@ -35,7 +35,8 @@ struct nf_queue_entry {
 struct nf_queue_handler {
 	int		(*outfn)(struct nf_queue_entry *entry,
 				 unsigned int queuenum);
-	void		(*nf_hook_drop)(struct net *net);
+	void		(*nf_hook_drop)(struct net *net,
+					const struct nf_hook_ops *ops);
 };
 
 void nf_register_queue_handler(const struct nf_queue_handler *qh);
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 940dea2663e9..44c856c1e621 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -529,7 +529,7 @@ static void __nf_unregister_net_hook(struct net *net, int pf,
 	if (!p)
 		return;
 
-	nf_queue_nf_hook_drop(net);
+	nf_queue_nf_hook_drop(net, reg);
 	nf_hook_entries_free(p);
 }
 
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index f9b8927327ba..8514a37c29fa 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -2410,7 +2410,7 @@ nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
 
 		if (atomic_read(&cnet->count) == 0)
 			continue;
-		nf_queue_nf_hook_drop(net);
+		nf_queue_nf_hook_drop(net, NULL);
 	}
 	up_read(&net_rwsem);
 
diff --git a/net/netfilter/nf_internals.h b/net/netfilter/nf_internals.h
index 25403023060b..ce5aff2cae71 100644
--- a/net/netfilter/nf_internals.h
+++ b/net/netfilter/nf_internals.h
@@ -24,7 +24,7 @@
 #define CTA_FILTER_FLAG(ctattr) CTA_FILTER_F_ ## ctattr
 
 /* nf_queue.c */
-void nf_queue_nf_hook_drop(struct net *net);
+void nf_queue_nf_hook_drop(struct net *net, const struct nf_hook_ops *ops);
 
 /* nf_log.c */
 int __init netfilter_log_init(void);
diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index 73363ceedebe..166d05e994ac 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -129,14 +129,14 @@ bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
 }
 EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
 
-void nf_queue_nf_hook_drop(struct net *net)
+void nf_queue_nf_hook_drop(struct net *net, const struct nf_hook_ops *ops)
 {
 	const struct nf_queue_handler *qh;
 
 	rcu_read_lock();
 	qh = rcu_dereference(nf_queue_handler);
 	if (qh)
-		qh->nf_hook_drop(net);
+		qh->nf_hook_drop(net, ops);
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(nf_queue_nf_hook_drop);
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index a3bc00280051..00b76c25d55c 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -1559,9 +1559,39 @@ static struct notifier_block nfqnl_dev_notifier = {
 	.notifier_call	= nfqnl_rcv_dev_event,
 };
 
-static void nfqnl_nf_hook_drop(struct net *net)
+/* Match the entries whose hook_index points into the hook array that
+ * __nf_unregister_net_hook() replaces when it removes @ops.
+ *
+ * ops->pf/hooknum name the hook as registered; entry->state.pf/hook
+ * name the array actually traversed - they differ only for NFPROTO_INET.
+ * Every other family uses the array of its own name.
+ */
+static int nf_hook_cmp(struct nf_queue_entry *entry, unsigned long ops_ptr)
+{
+	const struct nf_hook_ops *ops = (const struct nf_hook_ops *)ops_ptr;
+	unsigned int hooknum = ops->hooknum;
+	u8 pf = ops->pf;
+
+	/* same translation as nf_static_key_inc() */
+	if (pf == NFPROTO_INET && hooknum == NF_INET_INGRESS) {
+		pf = NFPROTO_NETDEV;
+		hooknum = NF_NETDEV_INGRESS;
+	}
+
+	if (entry->state.hook != hooknum)
+		return 0;
+
+	if (pf == NFPROTO_INET)
+		return entry->state.pf == NFPROTO_IPV4 ||
+		       entry->state.pf == NFPROTO_IPV6;
+
+	return entry->state.pf == pf;
+}
+
+static void nfqnl_nf_hook_drop(struct net *net, const struct nf_hook_ops *ops)
 {
 	struct nfnl_queue_net *q = nfnl_queue_pernet(net);
+	nfqnl_cmpfn cmpfn = NULL;
 	int i;
 
 	/* This function is also called on net namespace error unwind,
@@ -1574,12 +1604,19 @@ static void nfqnl_nf_hook_drop(struct net *net)
 	if (!q)
 		return;
 
+	/* ops is NULL when the caller is not unregistering a hook but
+	 * removing an object queued packets may reference, every entry
+	 * has to go
+	 */
+	if (ops)
+		cmpfn = nf_hook_cmp;
+
 	for (i = 0; i < INSTANCE_BUCKETS; i++) {
 		struct nfqnl_instance *inst;
 		struct hlist_head *head = &q->instance_table[i];
 
 		hlist_for_each_entry_rcu(inst, head, hlist)
-			nfqnl_flush(inst, NULL, 0);
+			nfqnl_flush(inst, cmpfn, (unsigned long)ops);
 	}
 }
 
diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c
index 3c4c2faa7398..5a8db5592036 100644
--- a/net/netfilter/nft_ct.c
+++ b/net/netfilter/nft_ct.c
@@ -542,7 +542,7 @@ static void __nft_ct_set_destroy(const struct nft_ctx *ctx, struct nft_ct *priv)
 #endif
 #ifdef CONFIG_NF_CONNTRACK_ZONES
 	case NFT_CT_ZONE:
-		nf_queue_nf_hook_drop(ctx->net);
+		nf_queue_nf_hook_drop(ctx->net, NULL);
 		mutex_lock(&nft_ct_pcpu_mutex);
 		if (--nft_ct_pcpu_template_refcnt == 0)
 			nft_ct_tmpl_put_pcpu();
-- 
2.47.3

[PATCH net-next 05/15] selftests: netfilter: nft_queue: check the scope of the hook drop flush

[Pablo Neira Ayuso]

From: Antonio Ojea <aojea@google.com>

Add test_hook_drop_scope. It queues 20 UDP packets from an inet output
chain to a queue program that holds all verdicts, deletes a base chain
while they wait, and reads the queue length from
/proc/net/netfilter/nfnetlink_queue right after the deletion. It then
releases the queue program and checks with a counter in the input
chain and the packet total of the queue program that the surviving
packets are delivered.

Deleting a base chain at another hook point (ip6 prerouting) must keep
the 20 queued packets. Deleting a base chain at the queueing hook point
(inet output, another priority) drops them, because the index of a
queued packet into the hook array of its hook point is stale once that
array changed. The second case documents the remaining behaviour so
that a change to it is visible.

To hold the packets without depending on timing, add the -H option to
the nf_queue helper: it blocks SIGUSR1, reads the first packet and
waits in sigwait() until it receives SIGUSR1, then sends the verdicts
as usual. The test sends the signal after the ruleset change, so the
queue length it reads is exact on slow machines too.

Without the previous patch the first case fails: 0 of 20 packets remain
queued after the deletion and none is delivered.

The test and the helper option were written with an LLM coding
assistant from a task description; the author reviewed the result,
and validated the test in virtme-ng on kernels with and without the
previous patch.

Assisted-by: LLM
Signed-off-by: Antonio Ojea <aojea@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 .../selftests/net/netfilter/nf_queue.c        |  22 +++-
 .../selftests/net/netfilter/nft_queue.sh      | 108 ++++++++++++++++++
 2 files changed, 129 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/netfilter/nf_queue.c b/tools/testing/selftests/net/netfilter/nf_queue.c
index 8bbec37f5356..cca6c3cfa9e4 100644
--- a/tools/testing/selftests/net/netfilter/nf_queue.c
+++ b/tools/testing/selftests/net/netfilter/nf_queue.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include <errno.h>
+#include <signal.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdint.h>
@@ -21,6 +22,7 @@ struct options {
 	bool failopen;
 	bool out_of_order;
 	bool bogus_verdict;
+	bool hold;
 	int verbose;
 	unsigned int queue_num;
 	unsigned int timeout;
@@ -34,6 +36,7 @@ static struct options opts;
 static void help(const char *p)
 {
 	printf("Usage: %s [-c|-v [-vv] ] [-o] [-O] [-b] [-t timeout] [-q queue_num] [-Qdst_queue ] [ -d ms_delay ] [-G]\n", p);
+	printf("          [-H] (hold verdicts until SIGUSR1 is received)\n");
 }
 
 static int parse_attr_cb(const struct nlattr *attr, void *data)
@@ -280,6 +283,7 @@ static int mainloop(void)
 	uint32_t ooo_ids[16];
 	unsigned int portid;
 	int ooo_count = 0;
+	sigset_t hold_set;
 	char *buf;
 	int ret;
 
@@ -289,6 +293,12 @@ static int mainloop(void)
 		exit(EXIT_FAILURE);
 	}
 
+	/* -H: keep SIGUSR1 pending until the first packet is read */
+	sigemptyset(&hold_set);
+	sigaddset(&hold_set, SIGUSR1);
+	if (opts.hold)
+		sigprocmask(SIG_BLOCK, &hold_set, NULL);
+
 	nl = open_queue();
 	portid = mnl_socket_get_portid(nl);
 
@@ -320,6 +330,13 @@ static int mainloop(void)
 		}
 
 		id = ret - MNL_CB_OK;
+		if (opts.hold) {
+			int sig;
+
+			sigwait(&hold_set, &sig);
+			opts.hold = false;
+		}
+
 		if (opts.delay_ms)
 			sleep_ms(opts.delay_ms);
 
@@ -364,7 +381,7 @@ static void parse_opts(int argc, char **argv)
 {
 	int c;
 
-	while ((c = getopt(argc, argv, "chvoObt:q:Q:d:G")) != -1) {
+	while ((c = getopt(argc, argv, "chvoObt:q:Q:d:GH")) != -1) {
 		switch (c) {
 		case 'c':
 			opts.count_packets = true;
@@ -373,6 +390,9 @@ static void parse_opts(int argc, char **argv)
 			help(argv[0]);
 			exit(0);
 			break;
+		case 'H':
+			opts.hold = true;
+			break;
 		case 'q':
 			opts.queue_num = atoi(optarg);
 			if (opts.queue_num > 0xffff)
diff --git a/tools/testing/selftests/net/netfilter/nft_queue.sh b/tools/testing/selftests/net/netfilter/nft_queue.sh
index c8d1f2eb4133..a07652813a4b 100755
--- a/tools/testing/selftests/net/netfilter/nft_queue.sh
+++ b/tools/testing/selftests/net/netfilter/nft_queue.sh
@@ -861,6 +861,113 @@ test_queue_bridge()
 	test_queue 20 "bridge"
 }
 
+hook_drop_delivered()
+{
+	ip netns exec "$ns1" nft list counter inet nfqscope delivered |
+		sed -n 's/.*packets \([0-9]*\) .*/\1/p'
+}
+
+hook_drop_queued()
+{
+	ip netns exec "$ns1" awk '$1 == 1 { print $3 }' /proc/self/net/netfilter/nfnetlink_queue
+}
+
+hook_drop_all_queued()
+{
+	[ "$(hook_drop_queued)" = "$1" ]
+}
+
+# hook_drop_case <keep|drop> <description> <nft command...>
+#
+# 1. The inet output chain sends udp packets to port 12345 to queue 1,
+#    the inet input chain counts them once they are accepted.
+# 2. nf_queue -H reads the packets but sends no verdict until it gets
+#    SIGUSR1, so the 20 packets sent stay in the kernel queue.
+# 3. The nft command removes a base chain while they are queued.  The
+#    queue length in /proc right after it tells if the kernel dropped
+#    them: still 20, or 0.
+# 4. SIGUSR1 releases nf_queue.  If the kernel kept the packets they are
+#    accepted now and reach the input counter.  If it dropped them the
+#    first verdict fails with ENOENT and nothing is counted.
+hook_drop_case()
+{
+	local expect="$1"
+	local desc="$2"
+	local packets=20
+	local delivered queued result
+	shift 2
+
+ip netns exec "$ns1" nft -f /dev/stdin <<EOF
+flush ruleset
+table inet nfqscope {
+	chain output {
+		type filter hook output priority 0; policy accept;
+		udp dport 12345 queue num 1
+	}
+	chain input {
+		type filter hook input priority 0; policy accept;
+		udp dport 12345 counter name delivered
+	}
+	chain output2 {
+		type filter hook output priority 100; policy accept;
+	}
+	counter delivered {}
+}
+table ip6 unrelated {
+	chain prerouting {
+		type filter hook prerouting priority 0; policy accept;
+	}
+}
+EOF
+	ip netns exec "$ns1" ./nf_queue -c -q 1 -H -t "$timeout" > "$TMPFILE1" 2>&1 &
+	local nfqpid=$!
+
+	busywait "$BUSYWAIT_TIMEOUT" nf_queue_wait "$ns1" 1
+
+	ip netns exec "$ns1" bash -c \
+		"for i in \$(seq $packets); do echo x > /dev/udp/127.0.0.1/12345; done"
+
+	busywait "$BUSYWAIT_TIMEOUT" hook_drop_all_queued "$packets"
+
+	ip netns exec "$ns1" nft "$@"
+	queued=$(hook_drop_queued)
+
+	kill -USR1 "$nfqpid"
+	wait "$nfqpid"
+	delivered=$(hook_drop_delivered)
+
+	if [ "$queued" = "$packets" ] && [ "$delivered" = "$packets" ] &&
+	   grep -q "^$packets packets total" "$TMPFILE1"; then
+		result="keep"
+	elif [ "$queued" = "0" ] && [ "$delivered" = "0" ]; then
+		result="drop"
+	else
+		result="inconsistent"
+	fi
+
+	if [ "$result" = "$expect" ]; then
+		echo "PASS: $desc: queued packets $result"
+	else
+		echo "FAIL: $desc: queued packets $result, expected $expect" 1>&2
+		echo "      $queued of $packets queued after the change, $delivered delivered" 1>&2
+		ret=1
+	fi
+}
+
+test_hook_drop_scope()
+{
+	# the hook array of another hook point changes, queued packets stay
+	hook_drop_case keep "base chain removed at another hook point" \
+		delete chain ip6 unrelated prerouting
+
+	# the hook array of the queueing hook point changes, the position of
+	# the queued packets in it is stale, they are dropped
+	hook_drop_case drop "base chain removed at the queueing hook point" \
+		delete chain inet nfqscope output2
+
+	ip netns exec "$ns1" nft flush ruleset
+}
+
 ip netns exec "$nsrouter" sysctl net.ipv6.conf.all.forwarding=1 > /dev/null
 ip netns exec "$nsrouter" sysctl net.ipv4.conf.veth0.forwarding=1 > /dev/null
 ip netns exec "$nsrouter" sysctl net.ipv4.conf.veth1.forwarding=1 > /dev/null
@@ -909,6 +1016,7 @@ test_queue_stress
 # should be last, adds vrf device in ns1 and changes routes
 test_icmp_vrf
 test_queue_removal
+test_hook_drop_scope
 
 # turns router into a bridge
 test_queue_bridge
-- 
2.47.3

[PATCH net-next 06/15] 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 8514a37c29fa..931b76aacd93 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 07/15] 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 08/15] 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 09/15] 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.

This patch also updates the logic to drop malformed packets, before this
patch NFT_BREAK was used as a verdict instead.

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

[PATCH net-next 10/15] selftests: netfilter: fix return value in zone subtest

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

zone subtest prints FAIL, but did not set 'ret=1', so kselftest
framework reports success.

While at it, also fail when "nft -f" returns an error.

Noticed thanks to a (broken) local patch that should have caused this
selftest (resp. the kselftest framework) to report a failure.

Fixes: 33b8aad21ac1 ("selftests: netfilter: add a vrf+conntrack testcase")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 .../selftests/net/netfilter/conntrack_vrf.sh  | 25 ++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/netfilter/conntrack_vrf.sh b/tools/testing/selftests/net/netfilter/conntrack_vrf.sh
index 207b79932d91..2dbfabaadf4b 100755
--- a/tools/testing/selftests/net/netfilter/conntrack_vrf.sh
+++ b/tools/testing/selftests/net/netfilter/conntrack_vrf.sh
@@ -84,7 +84,7 @@ busywait $BUSYWAIT_TIMEOUT listener_ready "$ns1"
 # as decided by the first iteration of the ruleset.
 test_ct_zone_in()
 {
-ip netns exec "$ns0" nft -f - <<EOF
+if ! ip netns exec "$ns0" nft -f - <<EOF
 table testct {
 	chain rawpre {
 		type filter hook prerouting priority raw;
@@ -105,6 +105,12 @@ table testct {
 	}
 }
 EOF
+	then
+		echo "FAIL: cannot load testct nft ruleset"
+		ret=1
+		return
+	fi
+
 	ip netns exec "$ns1" ping -W 1 -c 1 -I veth0 "$IP0" > /dev/null
 
 	# should be in zone 1, not zone 2
@@ -113,6 +119,7 @@ EOF
 		echo "PASS: entry found in conntrack zone 1"
 	else
 		echo "FAIL: entry not found in conntrack zone 1"
+		ret=1
 		count=$(ip netns exec "$ns0" conntrack -L -s $IP1 -d $IP0 -p icmp --zone 2 2> /dev/null | wc -l)
 		if [ "$count" -eq 1 ]; then
 			echo "FAIL: entry found in zone 2 instead"
@@ -137,7 +144,7 @@ test_masquerade_vrf()
 
 	ip netns exec "$ns0" conntrack -F 2>/dev/null
 
-ip netns exec "$ns0" nft -f - <<EOF
+if ! ip netns exec "$ns0" nft -f - <<EOF
 flush ruleset
 table ip nat {
 	chain rawout {
@@ -158,6 +165,12 @@ table ip nat {
 	}
 }
 EOF
+	then
+		echo "FAIL: cannot load ip nat nft ruleset"
+		ret=1
+		return
+	fi
+
 	if ! ip netns exec "$ns0" ip vrf exec tvrf socat -u -4 STDIN TCP:"$IP1":55555 < /dev/null > /dev/null;then
 		echo "FAIL: connect failure with masquerade + sport rewrite on vrf device"
 		ret=1
@@ -184,7 +197,7 @@ EOF
 test_masquerade_veth()
 {
 	ip netns exec "$ns0" conntrack -F 2>/dev/null
-ip netns exec "$ns0" nft -f - <<EOF
+if ! ip netns exec "$ns0" nft -f - <<EOF
 flush ruleset
 table ip nat {
 	chain postrouting {
@@ -193,6 +206,12 @@ table ip nat {
 	}
 }
 EOF
+	then
+		echo "FAIL: cannot load ip nat postrouting ruleset"
+		ret=1
+		return
+	fi
+
 	if ! ip netns exec "$ns0" ip vrf exec tvrf socat -u -4 STDIN TCP:"$IP1":55555 < /dev/null > /dev/null;then
 		echo "FAIL: connect failure with masquerade + sport rewrite on veth device"
 		ret=1
-- 
2.47.3

[PATCH net-next 11/15] netfilter: nft_compat: restrict raw table targets/matches

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

xt targets and matches declaring .table = "raw" (CT, NOTRACK) rely on
only ever running in the legacy raw table's prerouting/output chains,
ahead of conntrack. nft_compat_chain_validate_dependency() already
enforces this kind of correspondence for "nat" by requiring the chain
type to actually be NAT, but did nothing for "raw": a rule wrapping
the CT target could be loaded into any hook and any priority via
nft_compat, including after the real conntrack hook has already run.

The CT target attaches a conntrack template to the skb when none is
set yet.

Require that a "raw" table dependency actually matches what xtables
enforces via the implict/builtin table dependency.

Fixes: 0ca743a55991 ("netfilter: nf_tables: add compatibility layer for x_tables")
Assisted-by: LLM
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nft_compat.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 63864b928259..88ddaf47f587 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -14,6 +14,7 @@
 #include <linux/netfilter/nf_tables.h>
 #include <linux/netfilter/nf_tables_compat.h>
 #include <linux/netfilter/x_tables.h>
+#include <linux/netfilter_ipv4.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter_ipv6/ip6_tables.h>
 #include <linux/netfilter_bridge/ebtables.h>
@@ -45,6 +46,20 @@ static int nft_compat_chain_validate_dependency(const struct nft_ctx *ctx,
 			type = NFT_CHAIN_T_NAT;
 		if (basechain->type->type != type)
 			return -EINVAL;
+	} else if (strcmp(tablename, "raw") == 0) {
+		/* iptables-nft emulates the legacy raw table, which only
+		 * ever has prerouting/output chains at this exact priority.
+		 */
+		if (ctx->family != NFPROTO_IPV4 &&
+		    ctx->family != NFPROTO_IPV6)
+			return -EINVAL;
+
+		if (basechain->ops.hooknum != NF_INET_PRE_ROUTING &&
+		    basechain->ops.hooknum != NF_INET_LOCAL_OUT)
+			return -EINVAL;
+
+		if (basechain->ops.priority != NF_IP_PRI_RAW)
+			return -EINVAL;
 	}
 
 	return 0;
-- 
2.47.3

[PATCH net-next 12/15] 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 c8c29a9a1684..29d1a9f4a362 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 13/15] 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 29d1a9f4a362..8379b45b2dad 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 14/15] 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 8379b45b2dad..29a769736dbf 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 15/15] 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 29a769736dbf..e13f9397e8cb 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -587,23 +587,44 @@ 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;
@@ -614,11 +635,12 @@ 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;
@@ -628,81 +650,91 @@ 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,
@@ -809,10 +841,10 @@ 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);
@@ -825,10 +857,10 @@ 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) {
@@ -839,7 +871,7 @@ 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;
@@ -1137,7 +1169,7 @@ 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;
@@ -1153,11 +1185,10 @@ 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) {
@@ -1168,7 +1199,7 @@ 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

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

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - How the issue was discovered, e.g. hit in production, hit during
   development, syzbot report, manual code inspection, LLM or static
   analysis tool scan.

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
   the symptoms, like the stack trace or error messages.

Please do not repost the series just to address the above. Instead,
reply to this email with the missing information, so that reviewers
can take it into account. If the series needs another revision for
other reasons, please include the information in the commit messages
then.

The evaluation is done by an LLM so it may be wrong, if you think
that is the case please reply and explain.

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

[Pablo Neira Ayuso]

Hi,

On Sun, Oct 18, 2026 at 01:03:17AM +0000, netdev-bot+sinfo@kernel.org wrote:
> Hi!
> 
> This is an automated message. This series looks like a fix, but its
> commit messages seem to be missing some information:
> 
>  - How the issue was discovered, e.g. hit in production, hit during
>    development, syzbot report, manual code inspection, LLM or static
>    analysis tool scan.
>
>  - Whether the issue was actually triggered, or is only theoretical
>    (e.g. found by code inspection). If it was triggered please include
>    the symptoms, like the stack trace or error messages.

Yes, this contains some low priority fixes as well as enhancements:

1) For the br_netfilter patch, existing limitations are known and
   issues keep popping from time to time, let's prepare for deprecation.

2) Found by Jakub in NIPA.

3) For the IPVS sync message overflow: found via manual code
   inspection. It is theoretical for modern kernels - the description
   notes it "can only happen in very old 2.6 kernels," so it was not
   triggered in any current production or test environment.

4 and 5) unclear if it was found in production, but it comes from
   third party software developer with realistic use-cases.

6) For the conntrack gc worker UaF: found via manual code inspection.
   It is described as "unlikely," so it is theoretical - not
   observed as a triggered crash or stack trace.

7) For the nf_tables chain types UaF on module removal: found via
   manual code inspection. The race window (module removal while RCU
   readers are active) makes it theoretical in practice; no stack trace
   or production report is referenced.

8 and 9) Simplify nft_exthdr tcp option parsing.

10) fixes a conntrack_vrf.sh selftest which has been seen to be
   reporting bogus issues.

11) was found via LLM that I am aware of.

12) is preparation work from Lorenzo Bianconi towards adding
    IPv4-over-IPv6 and vice-versa. 

This answer to this email has been assisted by LLM.

> Please do not repost the series just to address the above. Instead,
> reply to this email with the missing information, so that reviewers
> can take it into account. If the series needs another revision for
> other reasons, please include the information in the commit messages
> then.
> 
> The evaluation is done by an LLM so it may be wrong, if you think
> that is the case please reply and explain.