linux-stable.git/include/net/netfilter, branch v7.0.11

netfilter: nf_conntrack_expect: restore helper propagation via expectation

2026-06-01T15:54:35+00:00

[ Upstream commit dcb0f9aefdd604d36710fda53c25bd7cf4a3e37a ]

A recent series to fix expectations broke helper propagation via
expectation, this mechanism is used by the sip and h323 helper. This
also propagates the conntrack helper to expected connections. I changed
semantics of exp->helper which now tells us the actual helper that
created the expectation.

Add an explicit assign_helper field to expectations for this purpose
and update helpers to use it.

Restore this feature for userspace conntrack helper via ctnetlink
nfqueue integration so it is again possible to attach a helper to an
expectation, where it makes sense. This is not restored via ctnetlink
expectation creation as there is no client for such feature. Use the
expectation layer 4 protocol number for the helper lookup for
consistency.

Make sure the expectation using this helper propagation mechanism also
go away when the helper is unregistered.

Fixes: 9c42bc9db90a ("netfilter: nf_conntrack_expect: honor expectation helper field")
Fixes: 917b61fa2042 ("netfilter: ctnetlink: ignore explicit helper on new expectations")
Reported-by: Ilya Maximets 
Tested-by: Ilya Maximets 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: nf_queue: hold bridge skb->dev while queued

2026-06-01T15:54:23+00:00

commit e196115ec330a18de415bdb9f5071aa9f08e53ce upstream.

br_pass_frame_up() rewrites skb->dev from the ingress port to the bridge
master before queueing bridge LOCAL_IN packets. NFQUEUE only holds
references on state.in/out and bridge physdevs, so a queued bridge
packet can retain a freed bridge master in skb->dev until reinjection.

When the verdict is reinjected later, br_netif_receive_skb() re-enters
the receive path with skb->dev still pointing at the freed bridge master,
triggering a use-after-free.

Store skb->dev in the queue entry, hold a reference on it for the queue
lifetime, and use the saved device when dropping queued packets during
NETDEV_DOWN handling.

Fixes: ac2863445686 ("netfilter: bridge: add nf_afinfo to enable queuing to userspace")
Cc: stable@kernel.org
Reported-by: Yuan Tan 
Reported-by: Yifan Wu 
Reported-by: Juefei Pu 
Reported-by: Xin Liu 
Signed-off-by: Haoze Xie 
Signed-off-by: Ren Wei 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_tables: add hook transactions for device deletions

2026-05-23T11:09:26+00:00

[ Upstream commit 10f79dbd7719d1da9f5884d13060322d8729f091 ]

Restore the flag that indicates that the hook is going away, ie.
NFT_HOOK_REMOVE, but add a new transaction object to track deletion
of hooks without altering the basechain/flowtable hook_list during
the preparation phase.

The existing approach that moves the hook from the basechain/flowtable
hook_list to transaction hook_list breaks netlink dump path readers
of this RCU-protected list.

It should be possible use an array for nft_trans_hook to store the
deleted hooks to compact the representation but I am not expecting
many hook object, specially now that wildcard support for devices
is in place.

Note that the nft_trans_chain_hooks() list contains a list of struct
nft_trans_hook objects for DELCHAIN and DELFLOWTABLE commands, while
this list stores struct nft_hook objects for NEWCHAIN and NEWFLOWTABLE.
Note that new commands can be updated to use nft_trans_hook for
consistency.

This patch also adapts the event notification path to deal with the list
of hook transactions.

Fixes: 7d937b107108 ("netfilter: nf_tables: support for deleting devices in an existing netdev chain")
Fixes: b6d9014a3335 ("netfilter: nf_tables: delete flowtable hooks via transaction list")
Reported-by: Xiang Mei 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

netfilter: nfnetlink_queue: make hash table per queue

2026-04-08T11:34:51+00:00

Sharing a global hash table among all queues is tempting, but
it can cause crash:

BUG: KASAN: slab-use-after-free in nfqnl_recv_verdict+0x11ac/0x15e0 [nfnetlink_queue]
[..]
 nfqnl_recv_verdict+0x11ac/0x15e0 [nfnetlink_queue]
 nfnetlink_rcv_msg+0x46a/0x930
 kmem_cache_alloc_node_noprof+0x11e/0x450

struct nf_queue_entry is freed via kfree, but parallel cpu can still
encounter such an nf_queue_entry when walking the list.

Alternative fix is to free the nf_queue_entry via kfree_rcu() instead,
but as we have to alloc/free for each skb this will cause more mem
pressure.

Cc: Scott Mitchell 
Fixes: e19079adcd26 ("netfilter: nfnetlink_queue: optimize verdict lookup with hash table")
Signed-off-by: Florian Westphal

netfilter: nft_ct: fix use-after-free in timeout object destroy

2026-04-08T11:34:16+00:00

nft_ct_timeout_obj_destroy() frees the timeout object with kfree()
immediately after nf_ct_untimeout(), without waiting for an RCU grace
period. Concurrent packet processing on other CPUs may still hold
RCU-protected references to the timeout object obtained via
rcu_dereference() in nf_ct_timeout_data().

Add an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer
freeing until after an RCU grace period, matching the approach already
used in nfnetlink_cttimeout.c.

KASAN report:
 BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0
 Read of size 4 at addr ffff8881035fe19c by task exploit/80

 Call Trace:
  nf_conntrack_tcp_packet+0x1381/0x29d0
  nf_conntrack_in+0x612/0x8b0
  nf_hook_slow+0x70/0x100
  __ip_local_out+0x1b2/0x210
  tcp_sendmsg_locked+0x722/0x1580
  __sys_sendto+0x2d8/0x320

 Allocated by task 75:
  nft_ct_timeout_obj_init+0xf6/0x290
  nft_obj_init+0x107/0x1b0
  nf_tables_newobj+0x680/0x9c0
  nfnetlink_rcv_batch+0xc29/0xe00

 Freed by task 26:
  nft_obj_destroy+0x3f/0xa0
  nf_tables_trans_destroy_work+0x51c/0x5c0
  process_one_work+0x2c4/0x5a0

Fixes: 7e0b2b57f01d ("netfilter: nft_ct: add ct timeout support")
Cc: stable@vger.kernel.org
Signed-off-by: Tuan Do 
Signed-off-by: Florian Westphal

netfilter: nf_conntrack_expect: store netns and zone in expectation

2026-03-26T12:24:40+00:00

__nf_ct_expect_find() and nf_ct_expect_find_get() are called under
rcu_read_lock() but they dereference the master conntrack via
exp->master.

Since the expectation does not hold a reference on the master conntrack,
this could be dying conntrack or different recycled conntrack than the
real master due to SLAB_TYPESAFE_RCU.

Store the netns, the master_tuple and the zone in struct
nf_conntrack_expect as a safety measure.

This patch is required by the follow up fix not to dump expectations
that do not belong to this netns.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: ctnetlink: ensure safe access to master conntrack

2026-03-26T12:18:32+00:00

Holding reference on the expectation is not sufficient, the master
conntrack object can just go away, making exp->master invalid.

To access exp->master safely:

- Grab the nf_conntrack_expect_lock, this gets serialized with
  clean_from_lists() which also holds this lock when the master
  conntrack goes away.

- Hold reference on master conntrack via nf_conntrack_find_get().
  Not so easy since the master tuple to look up for the master conntrack
  is not available in the existing problematic paths.

This patch goes for extending the nf_conntrack_expect_lock section
to address this issue for simplicity, in the cases that are described
below this is just slightly extending the lock section.

The add expectation command already holds a reference to the master
conntrack from ctnetlink_create_expect().

However, the delete expectation command needs to grab the spinlock
before looking up for the expectation. Expand the existing spinlock
section to address this to cover the expectation lookup. Note that,
the nf_ct_expect_iterate_net() calls already grabs the spinlock while
iterating over the expectation table, which is correct.

The get expectation command needs to grab the spinlock to ensure master
conntrack does not go away. This also expands the existing spinlock
section to cover the expectation lookup too. I needed to move the
netlink skb allocation out of the spinlock to keep it GFP_KERNEL.

For the expectation events, the IPEXP_DESTROY event is already delivered
under the spinlock, just move the delivery of IPEXP_NEW under the
spinlock too because the master conntrack event cache is reached through
exp->master.

While at it, add lockdep notations to help identify what codepaths need
to grab the spinlock.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_conntrack_expect: honor expectation helper field

2026-03-26T12:18:31+00:00

The expectation helper field is mostly unused. As a result, the
netfilter codebase relies on accessing the helper through exp->master.

Always set on the expectation helper field so it can be used to reach
the helper.

nf_ct_expect_init() is called from packet path where the skb owns
the ct object, therefore accessing exp->master for the newly created
expectation is safe. This saves a lot of updates in all callsites
to pass the ct object as parameter to nf_ct_expect_init().

This is a preparation patches for follow up fixes.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

nf_tables: nft_dynset: fix possible stateful expression memleak in error path

2026-03-13T14:31:15+00:00

If cloning the second stateful expression in the element via GFP_ATOMIC
fails, then the first stateful expression remains in place without being
released.

   unreferenced object (percpu) 0x607b97e9cab8 (size 16):
     comm "softirq", pid 0, jiffies 4294931867
     hex dump (first 16 bytes on cpu 3):
       00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     backtrace (crc 0):
       pcpu_alloc_noprof+0x453/0xd80
       nft_counter_clone+0x9c/0x190 [nf_tables]
       nft_expr_clone+0x8f/0x1b0 [nf_tables]
       nft_dynset_new+0x2cb/0x5f0 [nf_tables]
       nft_rhash_update+0x236/0x11c0 [nf_tables]
       nft_dynset_eval+0x11f/0x670 [nf_tables]
       nft_do_chain+0x253/0x1700 [nf_tables]
       nft_do_chain_ipv4+0x18d/0x270 [nf_tables]
       nf_hook_slow+0xaa/0x1e0
       ip_local_deliver+0x209/0x330

Fixes: 563125a73ac3 ("netfilter: nftables: generalize set extension to support for several expressions")
Reported-by: Gurpreet Shergill 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Florian Westphal

netfilter: revert nft_set_rbtree: validate open interval overlap

2026-03-13T14:31:14+00:00

This reverts commit 648946966a08 ("netfilter: nft_set_rbtree: validate
open interval overlap").

There have been reports of nft failing to laod valid rulesets after this
patch was merged into -stable.

I can reproduce several such problem with recent nft versions, including
nft 1.1.6 which is widely shipped by distributions.

We currently have little choice here.
This commit can be resurrected at some point once the nftables fix that
triggers the false overlap positive has appeared in common distros
(see e83e32c8d1cd ("mnl: restore create element command with large batches" in
 nftables.git).

Fixes: 648946966a08 ("netfilter: nft_set_rbtree: validate open interval overlap")
Acked-by: Pablo Neira Ayuso 
Signed-off-by: Florian Westphal