linux-stable.git/net/netfilter, branch v6.18.50 Linux kernel stable tree netfilter: nf_tables: don't queue packet path object notifications 2026-09-02T12:31:50+00:00 Fourie Zhang littleddfu@gmail.com 2026-08-10T11:35:01+00:00 6fa88d11983c6fe693c13ed7c5b3b75ae9f39de6 commit 7904b94768e983bcb2be34a8d6d1f3450f5b838b upstream. All file:line references below are against v7.2-rc4 (ac5b0e5651b1). The trace was captured on 7.2.0-rc6-kasan72rc6 (075b74841bd0), where the same lines apply. nft_obj_notify() is exported and reached from the packet path. Its only in-tree caller is nft_quota_obj_eval() (net/netfilter/nft_quota.c:68), which notifies with GFP_ATOMIC while evaluating a rule for a transiting packet, holding no mutex. Since commit 67cc570edaa0 ("netfilter: nf_tables: coalesce multiple notifications into one skbuff") that notification is no longer sent immediately. __nft_obj_notify() queues it onto nft_net->notify_list via nft_notify_enqueue() (net/netfilter/nf_tables_api.c:1211), which is a bare list_add_tail(). notify_list has no lock of its own (include/net/netfilter/nf_tables.h:1951), it is serialised by commit_mutex: the six other enqueue sites all run inside a netlink transaction, and the drain in nft_commit_notify() (net/netfilter/nf_tables_api.c:10746) does list_del() + kfree_skb() from nf_tables_commit() with commit_mutex held. Sending packets through a chain that references a depleted quota object therefore races an unlocked list_add_tail() against list_del() + kfree_skb() on another CPU. The WRITE_ONCE(prev->next, new) in __list_add() then stores through an sk_buff that has already been freed: BUG: KASAN: slab-use-after-free in __nft_obj_notify+0x2c5/0x2d0 Write of size 8 at addr ff110001047183c0 by task poc/76 CPU: 0 UID: 1000 PID: 76 Comm: poc Tainted: G W 7.2.0-rc6-kasan72rc6 #4 Call Trace: <IRQ> __nft_obj_notify (include/linux/list.h:164 include/linux/list.h:191 net/netfilter/nf_tables_api.c:1211 net/netfilter/nf_tables_api.c:8743) nft_quota_obj_eval (net/netfilter/nft_quota.c:68) nft_do_chain_inet nf_hook_slow __ip_local_out ip_push_pending_frames udp_send_skb udp_sendmsg __x64_sys_sendto Allocated by task 77: __alloc_skb (net/core/skbuff.c:704) __nft_obj_notify (include/net/netlink.h:1055 net/netfilter/nf_tables_api.c:8731) nft_quota_obj_eval (net/netfilter/nft_quota.c:68) nft_do_chain Freed by task 79: nf_tables_commit (include/linux/skbuff.h:1332 net/netfilter/nf_tables_api.c:10759 net/netfilter/nf_tables_api.c:11185) nfnetlink_rcv_batch (net/netfilter/nfnetlink.c:574) netlink_unicast netlink_sendmsg The buggy address belongs to the cache skbuff_head_cache of size 232 Queueing from the packet path is wrong even leaving the race aside: notify_list is only drained by nft_commit_notify() from nf_tables_commit() (:11185), so a notification enqueued outside a transaction is not sent until some later netlink batch commits, if one ever does. The gfp argument that nft_obj_notify() still takes is a leftover of the pre-67cc570edaa0 behaviour, where this path called nfnetlink_send() directly. Restore that: split the message construction out into nft_obj_notify_alloc() and let each caller decide what to do with the skb. nft_obj_notify(), the exported one reached from the packet path, sends it straight away; nf_tables_obj_notify(), which runs under commit_mutex, keeps queueing it, so transaction notifications are still coalesced. Fixes: 67cc570edaa0 ("netfilter: nf_tables: coalesce multiple notifications into one skbuff") Cc: stable@kernel.org Reported-by: TencentOS Corvus AI <corvus@tencent.com> Assisted-by: tencentos-corvus-ai:kimi-k3 Signed-off-by: Fourie Zhang <fouriezhang@tencent.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 7904b94768e983bcb2be34a8d6d1f3450f5b838b upstream.

All file:line references below are against v7.2-rc4 (ac5b0e5651b1). The
trace was captured on 7.2.0-rc6-kasan72rc6 (075b74841bd0), where the same
lines apply.

nft_obj_notify() is exported and reached from the packet path. Its only
in-tree caller is nft_quota_obj_eval() (net/netfilter/nft_quota.c:68),
which notifies with GFP_ATOMIC while evaluating a rule for a transiting
packet, holding no mutex.

Since commit 67cc570edaa0 ("netfilter: nf_tables: coalesce multiple
notifications into one skbuff") that notification is no longer sent
immediately. __nft_obj_notify() queues it onto nft_net->notify_list via
nft_notify_enqueue() (net/netfilter/nf_tables_api.c:1211), which is a bare
list_add_tail(). notify_list has no lock of its own
(include/net/netfilter/nf_tables.h:1951), it is serialised by commit_mutex:
the six other enqueue sites all run inside a netlink transaction, and the
drain in nft_commit_notify() (net/netfilter/nf_tables_api.c:10746) does
list_del() + kfree_skb() from nf_tables_commit() with commit_mutex held.

Sending packets through a chain that references a depleted quota object
therefore races an unlocked list_add_tail() against list_del() +
kfree_skb() on another CPU. The WRITE_ONCE(prev->next, new) in __list_add()
then stores through an sk_buff that has already been freed:

  BUG: KASAN: slab-use-after-free in __nft_obj_notify+0x2c5/0x2d0
  Write of size 8 at addr ff110001047183c0 by task poc/76
  CPU: 0 UID: 1000 PID: 76 Comm: poc Tainted: G  W  7.2.0-rc6-kasan72rc6 #4
  Call Trace:
   <IRQ>
   __nft_obj_notify (include/linux/list.h:164 include/linux/list.h:191
                     net/netfilter/nf_tables_api.c:1211
                     net/netfilter/nf_tables_api.c:8743)
   nft_quota_obj_eval (net/netfilter/nft_quota.c:68)
   nft_do_chain_inet
   nf_hook_slow
   __ip_local_out
   ip_push_pending_frames
   udp_send_skb
   udp_sendmsg
   __x64_sys_sendto

  Allocated by task 77:
   __alloc_skb (net/core/skbuff.c:704)
   __nft_obj_notify (include/net/netlink.h:1055
                     net/netfilter/nf_tables_api.c:8731)
   nft_quota_obj_eval (net/netfilter/nft_quota.c:68)
   nft_do_chain

  Freed by task 79:
   nf_tables_commit (include/linux/skbuff.h:1332
                     net/netfilter/nf_tables_api.c:10759
                     net/netfilter/nf_tables_api.c:11185)
   nfnetlink_rcv_batch (net/netfilter/nfnetlink.c:574)
   netlink_unicast
   netlink_sendmsg

  The buggy address belongs to the cache skbuff_head_cache of size 232

Queueing from the packet path is wrong even leaving the race aside:
notify_list is only drained by nft_commit_notify() from nf_tables_commit()
(:11185), so a notification enqueued outside a transaction is not sent
until some later netlink batch commits, if one ever does.

The gfp argument that nft_obj_notify() still takes is a leftover of the
pre-67cc570edaa0 behaviour, where this path called nfnetlink_send()
directly. Restore that: split the message construction out into
nft_obj_notify_alloc() and let each caller decide what to do with the skb.
nft_obj_notify(), the exported one reached from the packet path, sends it
straight away; nf_tables_obj_notify(), which runs under commit_mutex, keeps
queueing it, so transaction notifications are still coalesced.

Fixes: 67cc570edaa0 ("netfilter: nf_tables: coalesce multiple notifications into one skbuff")
Cc: stable@kernel.org
Reported-by: TencentOS Corvus AI <corvus@tencent.com>
Assisted-by: tencentos-corvus-ai:kimi-k3
Signed-off-by: Fourie Zhang <fouriezhang@tencent.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
netfilter: nft_set_pipapo_avx2: add missing vzeroupper 2026-09-02T12:31:50+00:00 Eric Biggers ebiggers@kernel.org 2026-08-15T20:57:50+00:00 07ee91e6b7b0a8ed9a24c48f2f07decf1033bdf4 commit 55dd20f0f4b1be5c9c8a0275d8d763c86563eac2 upstream. Since pipapo_get_avx2() uses YMM registers, execute vzeroupper before returning from it. This is needed to avoid degrading the performance of any later SSE code that may happen to be executed. Fixes: 7400b063969b ("nft_set_pipapo: Introduce AVX2-based lookup implementation") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org> Reviewed-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 55dd20f0f4b1be5c9c8a0275d8d763c86563eac2 upstream.

Since pipapo_get_avx2() uses YMM registers, execute vzeroupper before
returning from it.  This is needed to avoid degrading the performance of
any later SSE code that may happen to be executed.

Fixes: 7400b063969b ("nft_set_pipapo: Introduce AVX2-based lookup implementation")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
netfilter: ipset: let destroy callbacks adjust ext mem size 2026-08-23T12:27:07+00:00 Florian Westphal fw@strlen.de 2026-08-06T14:17:50+00:00 a26a1be1b6541836453a2830504d1b3ec702e6c4 [ Upstream commit 490937b88cb592cc0c5367758edd700fd5abd15c ] For bitmap this change makes no difference, because destructors are called synchronously. List type however calls them via call_rcu() so accounting decrement can happen after list_set_flush() set ext_size to 0. 'set->elements = 0' can be removed for the same reason in the list type case, it calls 'set->elements--' for each element. Fixes: 9e41f26a505c ("netfilter: ipset: Count non-static extension memory for userspace") Suggested-by: Jozsef Kadlecsik <kadlec@netfilter.org> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 490937b88cb592cc0c5367758edd700fd5abd15c ]

For bitmap this change makes no difference, because destructors are
called synchronously.

List type however calls them via call_rcu() so accounting decrement can
happen after list_set_flush() set ext_size to 0.

'set->elements = 0' can be removed for the same reason in the list type
case, it calls 'set->elements--' for each element.

Fixes: 9e41f26a505c ("netfilter: ipset: Count non-static extension memory for userspace")
Suggested-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netfilter: ipset: fix list type element drift bug 2026-08-23T12:27:07+00:00 Florian Westphal fw@strlen.de 2026-08-06T13:53:41+00:00 29c011b3537d77eefe83be89db03dd2eecab1fb9 [ Upstream commit 4cbd69766b35a089664cadb1f613bb85f7ef77a9 ] If list_set_uadd() calls list_set_replace() to swap an expired entry, the element count remains the same, therefore the increment must be elided. Fixes: 702b71e7c666 ("netfilter: ipset: Add element count to all set types header") Link: https://sashiko.dev/#/patchset/20260806101947.2802-1-fw%40strlen.de Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 4cbd69766b35a089664cadb1f613bb85f7ef77a9 ]

If list_set_uadd() calls list_set_replace() to swap an expired entry,
the element count remains the same, therefore the increment must be elided.

Fixes: 702b71e7c666 ("netfilter: ipset: Add element count to all set types header")
Link: https://sashiko.dev/#/patchset/20260806101947.2802-1-fw%40strlen.de
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netfilter: flowtable: publish GC-visible tuple last 2026-08-23T12:27:07+00:00 Jérémy Jean Jeremy.Jean@oss.cyber.gouv.fr 2026-08-08T12:40:02+00:00 d9d3050a70efe217e73a0751e55fdae6a7092620 [ Upstream commit 2014ac62df9d45bb9a004a043e85df7be09ed780 ] nf_flow_table_iterate() only treats original-direction tuple nodes as owning entries. Publishing the original node first lets GC observe and free a flow while flow_offload_add() is still inserting the reply node. Publish the reply node first and the original node last so GC never sees a partially installed flow. KASAN can trigger slab-use-after-free read and write reports in the flowtable/rhashtable path (rht_deferred_worker, jhash, flow_offload_del, flow_offload_lookup, etc.). Fixes: ac2a66665e23 ("netfilter: add generic flow table infrastructure") Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr> Assisted-by: Codex:gpt-5 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 2014ac62df9d45bb9a004a043e85df7be09ed780 ]

nf_flow_table_iterate() only treats original-direction tuple nodes as
owning entries. Publishing the original node first lets GC observe and
free a flow while flow_offload_add() is still inserting the reply node.
Publish the reply node first and the original node last so GC never
sees a partially installed flow.

KASAN can trigger slab-use-after-free read and write reports in the
flowtable/rhashtable path (rht_deferred_worker, jhash, flow_offload_del,
flow_offload_lookup, etc.).

Fixes: ac2a66665e23 ("netfilter: add generic flow table infrastructure")
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Assisted-by: Codex:gpt-5
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netfilter: nf_tables_offload: suppress WARN_ON_ONCE for ENOMEM in abort path 2026-08-23T12:27:07+00:00 Alexey Velichayshiy a.velichayshiy@ispras.ru 2026-08-06T16:11:38+00:00 4a923fe60939a194777bc605036ce2147ab00c9d [ Upstream commit d02f592064347e0c1e0d84f24941ad338838cc48 ] In nft_flow_rule_offload_abort(), WARN_ON_ONCE(err) is triggered on every error during rollback, including -ENOMEM. Memory allocation failures are expected under low-memory conditions and do not indicate a kernel bug. Trace for example: nft_flow_offload_chain() // FLOW_BLOCK_BIND nft_flow_block_chain() nft_chain_offload_cmd() nft_block_offload_cmd() ->ndo_setup_tc() nsim_setup_tc() flow_block_cb_setup_simple() flow_block_cb_alloc() // fails to -ENOMEM The warning was reproduced on the 5.10 stable kernel under memory pressure via fault injection, but the underlying bug exists in mainline as well, as demonstrated by the ENOMEM trace above. The following splat was triggered during nf_tables transaction processing: WARNING: CPU: 0 PID: 8567 at net/netfilter/nf_tables_offload.c:532 nft_flow_rule_offload_abort net/netfilter/nf_tables_offload.c:532 [inline] WARNING: CPU: 0 PID: 8567 at net/netfilter/nf_tables_offload.c:532 nft_flow_rule_offload_commit+0x971/0xcd0 net/netfilter/nf_tables_offload.c:591 Modules linked in: CPU: 0 PID: 8567 Comm: syz-executor.0 Not tainted 5.10.260-syzkaller #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:nft_flow_rule_offload_abort net/netfilter/nf_tables_offload.c:532 [inline] RIP: 0010:nft_flow_rule_offload_commit+0x971/0xcd0 net/netfilter/nf_tables_offload.c:591 Call Trace: nf_tables_commit+0x3bd/0x4bd0 net/netfilter/nf_tables_api.c:8604 nfnetlink_rcv_batch+0xb1e/0x1f20 net/netfilter/nfnetlink.c:509 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:579 [inline] nfnetlink_rcv+0x3b3/0x420 net/netfilter/nfnetlink.c:597 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x6cd/0xa00 net/netfilter/af_netlink.c:1340 netlink_sendmsg+0x906/0xe10 net/netfilter/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] __sock_sendmsg+0x155/0x190 net/socket.c:663 ____sys_sendmsg+0x705/0x870 net/socket.c:2379 ___sys_sendmsg+0x100/0x170 net/socket.c:2433 __sys_sendmsg+0xe9/0x1c0 net/socket.c:2462 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x67/0xd1 Change the condition to WARN_ON_ONCE(err && err != -ENOMEM) so that warnings are only emitted for unexpected errors. This aligns with the common kernel practice of not warning on -ENOMEM. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: 63b48c73ff56 ("netfilter: nf_tables_offload: undo updates if transaction fails") Signed-off-by: Alexey Velichayshiy <a.velichayshiy@ispras.ru> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d02f592064347e0c1e0d84f24941ad338838cc48 ]

In nft_flow_rule_offload_abort(), WARN_ON_ONCE(err) is triggered on every
error during rollback, including -ENOMEM. Memory allocation failures are
expected under low-memory conditions and do not indicate a kernel bug.

Trace for example:
nft_flow_offload_chain() // FLOW_BLOCK_BIND
  nft_flow_block_chain()
    nft_chain_offload_cmd()
      nft_block_offload_cmd()
        ->ndo_setup_tc()
        nsim_setup_tc()
          flow_block_cb_setup_simple()
            flow_block_cb_alloc() // fails to -ENOMEM

The warning was reproduced on the 5.10 stable kernel under memory pressure
via fault injection, but the underlying bug exists in mainline as well,
as demonstrated by the ENOMEM trace above. The following splat was
triggered during nf_tables transaction processing:

WARNING: CPU: 0 PID: 8567 at net/netfilter/nf_tables_offload.c:532 nft_flow_rule_offload_abort net/netfilter/nf_tables_offload.c:532 [inline]
WARNING: CPU: 0 PID: 8567 at net/netfilter/nf_tables_offload.c:532 nft_flow_rule_offload_commit+0x971/0xcd0 net/netfilter/nf_tables_offload.c:591
Modules linked in:
CPU: 0 PID: 8567 Comm: syz-executor.0 Not tainted 5.10.260-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:nft_flow_rule_offload_abort net/netfilter/nf_tables_offload.c:532 [inline]
RIP: 0010:nft_flow_rule_offload_commit+0x971/0xcd0 net/netfilter/nf_tables_offload.c:591
Call Trace:
 nf_tables_commit+0x3bd/0x4bd0 net/netfilter/nf_tables_api.c:8604
 nfnetlink_rcv_batch+0xb1e/0x1f20 net/netfilter/nfnetlink.c:509
 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:579 [inline]
 nfnetlink_rcv+0x3b3/0x420 net/netfilter/nfnetlink.c:597
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x6cd/0xa00 net/netfilter/af_netlink.c:1340
 netlink_sendmsg+0x906/0xe10 net/netfilter/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:651 [inline]
 __sock_sendmsg+0x155/0x190 net/socket.c:663
 ____sys_sendmsg+0x705/0x870 net/socket.c:2379
 ___sys_sendmsg+0x100/0x170 net/socket.c:2433
 __sys_sendmsg+0xe9/0x1c0 net/socket.c:2462
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1

Change the condition to WARN_ON_ONCE(err && err != -ENOMEM) so that
warnings are only emitted for unexpected errors. This aligns with the
common kernel practice of not warning on -ENOMEM.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 63b48c73ff56 ("netfilter: nf_tables_offload: undo updates if transaction fails")
Signed-off-by: Alexey Velichayshiy <a.velichayshiy@ispras.ru>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netfilter: ipset: fix refcount race between list:set GC and swap 2026-08-23T12:27:07+00:00 Xiang Mei (Microsoft) xmei5@asu.edu 2026-07-22T22:38:32+00:00 cb20da33839f28f590c99f16bafaa6151451c0e8 [ Upstream commit 0c88868271653537ed443272dd8e7d13634d214b ] __ip_set_put_byindex() resolved the index to a set pointer under RCU, then took ip_set_ref_lock in __ip_set_put() to decrement set->ref. ip_set_swap() holds that same lock while swapping both the ip_set_list slots and the two sets' ref counters, so it can interleave between the dereference and the lock acquisition, leaving the caller to decrement a set whose reference already moved to the other index and hit BUG_ON(set->ref == 0). list_set_gc() reaches this from timer softirq, which the nfnl mutex does not serialize against swap: an expiring list:set member calls list_set_del() -> ip_set_put_byindex() while IPSET_CMD_SWAP runs on the referenced sets. Resolve the index and decrement under ip_set_ref_lock, as ip_set_swap() already does, keeping the refcount tied to the index rather than to a stale set pointer. kernel BUG at net/netfilter/ipset/ip_set_core.c:685! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:ip_set_put_byindex (net/netfilter/ipset/ip_set_core.c:870) Call Trace: <IRQ> list_set_del (net/netfilter/ipset/ip_set_list_set.c:159) set_cleanup_entries (net/netfilter/ipset/ip_set_list_set.c:181) list_set_gc (net/netfilter/ipset/ip_set_list_set.c:578) call_timer_fn (kernel/time/timer.c:1748) __run_timers (kernel/time/timer.c:1799 kernel/time/timer.c:2374) run_timer_softirq (kernel/time/timer.c:2405) </IRQ> Kernel panic - not syncing: Fatal exception in interrupt Fixes: 9076aea76538 ("netfilter: ipset: Increase the number of maximal sets automatically") Reported-by: AutonomousCodeSecurity@microsoft.com Signed-off-by: Xiang Mei (Microsoft) <xmei5@asu.edu> Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 0c88868271653537ed443272dd8e7d13634d214b ]

__ip_set_put_byindex() resolved the index to a set pointer under RCU,
then took ip_set_ref_lock in __ip_set_put() to decrement set->ref.
ip_set_swap() holds that same lock while swapping both the ip_set_list
slots and the two sets' ref counters, so it can interleave between the
dereference and the lock acquisition, leaving the caller to decrement a
set whose reference already moved to the other index and hit
BUG_ON(set->ref == 0). list_set_gc() reaches this from timer softirq,
which the nfnl mutex does not serialize against swap: an expiring
list:set member calls list_set_del() -> ip_set_put_byindex() while
IPSET_CMD_SWAP runs on the referenced sets.

Resolve the index and decrement under ip_set_ref_lock, as ip_set_swap()
already does, keeping the refcount tied to the index rather than to a
stale set pointer.

  kernel BUG at net/netfilter/ipset/ip_set_core.c:685!
  Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
  RIP: 0010:ip_set_put_byindex (net/netfilter/ipset/ip_set_core.c:870)
  Call Trace:
   <IRQ>
   list_set_del (net/netfilter/ipset/ip_set_list_set.c:159)
   set_cleanup_entries (net/netfilter/ipset/ip_set_list_set.c:181)
   list_set_gc (net/netfilter/ipset/ip_set_list_set.c:578)
   call_timer_fn (kernel/time/timer.c:1748)
   __run_timers (kernel/time/timer.c:1799 kernel/time/timer.c:2374)
   run_timer_softirq (kernel/time/timer.c:2405)
   </IRQ>
  Kernel panic - not syncing: Fatal exception in interrupt

Fixes: 9076aea76538 ("netfilter: ipset: Increase the number of maximal sets automatically")
Reported-by: AutonomousCodeSecurity@microsoft.com
Signed-off-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
ipvs: separate destination availability state 2026-08-23T12:26:54+00:00 Yizhou Zhao zhaoyz24@mails.tsinghua.edu.cn 2026-08-18T20:16:38+00:00 1a4c3ffe2a48b8023e744fda201afcc758a5b37f commit cdcc4e46180df8161f4d2f3c6fd6beaf6990133d upstream. IPVS configuration paths update destination availability while connection accounting updates destination overload state. The two independent states share dest->flags, so their read-modify-write updates can race and lose one another. Keep OVERLOAD in flags, where the preceding patch serializes its updates with dst_lock, and move AVAILABLE to cflags. This keeps configuration- controlled availability out of the scheduler hot cacheline until a scheduler needs to check it. It also prevents availability updates from clobbering overload state. The destination status bits are not exposed through the IPVS sockopt or netlink interfaces, so keep their definitions in the internal IPVS header. Readers can still observe stale destination state; this does not provide a cross-field snapshot. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn> Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn> Reported-by: Ao Wang <wangao@seu.edu.cn> Reported-by: Xuewei Feng <fengxw06@126.com> Reported-by: Qi Li <qli01@tsinghua.edu.cn> Reported-by: Ke Xu <xuke@tsinghua.edu.cn> Link: https://lore.kernel.org/all/8913381c-1e02-35c7-0ec4-61de5a12fd35@ssi.bg/ Assisted-by: Claude-Code:GLM-5.2 Suggested-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> (cherry picked from commit cdcc4e46180df8161f4d2f3c6fd6beaf6990133d) [ Julian: Backport by removing the hunks from ip_vs_xmit.c ] Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Sasha Levin <sashal@kernel.org> 
commit cdcc4e46180df8161f4d2f3c6fd6beaf6990133d upstream.

IPVS configuration paths update destination availability while connection
accounting updates destination overload state. The two independent states
share dest->flags, so their read-modify-write updates can race and lose one
another.

Keep OVERLOAD in flags, where the preceding patch serializes its updates
with dst_lock, and move AVAILABLE to cflags. This keeps configuration-
controlled availability out of the scheduler hot cacheline until a
scheduler needs to check it. It also prevents availability updates from
clobbering overload state.

The destination status bits are not exposed through the IPVS sockopt or
netlink interfaces, so keep their definitions in the internal IPVS header.

Readers can still observe stale destination state; this does not provide a
cross-field snapshot.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Reported-by: Yuxiang Yang <yangyx22@mails.tsinghua.edu.cn>
Reported-by: Ao Wang <wangao@seu.edu.cn>
Reported-by: Xuewei Feng <fengxw06@126.com>
Reported-by: Qi Li <qli01@tsinghua.edu.cn>
Reported-by: Ke Xu <xuke@tsinghua.edu.cn>
Link: https://lore.kernel.org/all/8913381c-1e02-35c7-0ec4-61de5a12fd35@ssi.bg/
Assisted-by: Claude-Code:GLM-5.2
Suggested-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
(cherry picked from commit cdcc4e46180df8161f4d2f3c6fd6beaf6990133d)
[ Julian: Backport by removing the hunks from ip_vs_xmit.c ]
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netfilter: flowtable: ensure sufficient headroom in xmit path 2026-08-19T16:18:21+00:00 Pablo Neira Ayuso pablo@netfilter.org 2026-04-30T14:49:48+00:00 1eb0dc458b6e8efc3a9cf02ec3ccd0f20576910e commit ef4f741e8627512cb8c82f59a1fc7aacd854aadf upstream. Check for headroom and call skb_expand_head() like in the IP output path to ensure there is sufficient headroom for the mac header when forwarding this packet as suggested by sashiko. Fixes: b5964aac51e0 ("netfilter: flowtable: consolidate xmit path") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ef4f741e8627512cb8c82f59a1fc7aacd854aadf upstream.

Check for headroom and call skb_expand_head() like in the IP output
path to ensure there is sufficient headroom for the mac header when
forwarding this packet as suggested by sashiko.

Fixes: b5964aac51e0 ("netfilter: flowtable: consolidate xmit path")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
netfilter: always set route tuple out ifindex 2026-08-19T16:18:21+00:00 Lorenzo Bianconi lorenzo@kernel.org 2025-12-01T10:22:45+00:00 99ec511f258e082fc7310990a6cf2023526ee7d6 commit 2bdc536c9da7fa08baf0fafe9d91243b83cb9c8b upstream. Always set nf_flow_route tuple out ifindex even if the indev is not one of the flowtable configured devices since otherwise the outdev lookup in nf_flow_offload_ip_hook() or nf_flow_offload_ipv6_hook() for FLOW_OFFLOAD_XMIT_NEIGH flowtable entries will fail. The above issue occurs in the following configuration since IP6IP6 tunnel does not support flowtable acceleration yet: $ip addr show 5: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether 00:11:22:33:22:55 brd ff:ff:ff:ff:ff:ff link-netns ns1 inet6 2001:db8:1::2/64 scope global nodad valid_lft forever preferred_lft forever inet6 fe80::211:22ff:fe33:2255/64 scope link tentative proto kernel_ll valid_lft forever preferred_lft forever 6: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000 link/ether 00:22:22:33:22:55 brd ff:ff:ff:ff:ff:ff link-netns ns3 inet6 2001:db8:2::1/64 scope global nodad valid_lft forever preferred_lft forever inet6 fe80::222:22ff:fe33:2255/64 scope link tentative proto kernel_ll valid_lft forever preferred_lft forever 7: tun0@NONE: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1452 qdisc noqueue state UNKNOWN group default qlen 1000 link/tunnel6 2001:db8:2::1 peer 2001:db8:2::2 permaddr a85:e732:2c37:: inet6 2002:db8:1::1/64 scope global nodad valid_lft forever preferred_lft forever inet6 fe80::885:e7ff:fe32:2c37/64 scope link proto kernel_ll valid_lft forever preferred_lft forever $ip -6 route show 2001:db8:1::/64 dev eth0 proto kernel metric 256 pref medium 2001:db8:2::/64 dev eth1 proto kernel metric 256 pref medium 2002:db8:1::/64 dev tun0 proto kernel metric 256 pref medium default via 2002:db8:1::2 dev tun0 metric 1024 pref medium $nft list ruleset table inet filter { flowtable ft { hook ingress priority filter devices = { eth0, eth1 } } chain forward { type filter hook forward priority filter; policy accept; meta l4proto { tcp, udp } flow add @ft } } Fixes: b5964aac51e0 ("netfilter: flowtable: consolidate xmit path") Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2bdc536c9da7fa08baf0fafe9d91243b83cb9c8b upstream.

Always set nf_flow_route tuple out ifindex even if the indev is not one
of the flowtable configured devices since otherwise the outdev lookup in
nf_flow_offload_ip_hook() or nf_flow_offload_ipv6_hook() for
FLOW_OFFLOAD_XMIT_NEIGH flowtable entries will fail.
The above issue occurs in the following configuration since IP6IP6
tunnel does not support flowtable acceleration yet:

$ip addr show
5: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:11:22:33:22:55 brd ff:ff:ff:ff:ff:ff link-netns ns1
    inet6 2001:db8:1::2/64 scope global nodad
       valid_lft forever preferred_lft forever
    inet6 fe80::211:22ff:fe33:2255/64 scope link tentative proto kernel_ll
       valid_lft forever preferred_lft forever
6: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:22:22:33:22:55 brd ff:ff:ff:ff:ff:ff link-netns ns3
    inet6 2001:db8:2::1/64 scope global nodad
       valid_lft forever preferred_lft forever
    inet6 fe80::222:22ff:fe33:2255/64 scope link tentative proto kernel_ll
       valid_lft forever preferred_lft forever
7: tun0@NONE: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1452 qdisc noqueue state UNKNOWN group default qlen 1000
    link/tunnel6 2001:db8:2::1 peer 2001:db8:2::2 permaddr a85:e732:2c37::
    inet6 2002:db8:1::1/64 scope global nodad
       valid_lft forever preferred_lft forever
    inet6 fe80::885:e7ff:fe32:2c37/64 scope link proto kernel_ll
       valid_lft forever preferred_lft forever

$ip -6 route show
2001:db8:1::/64 dev eth0 proto kernel metric 256 pref medium
2001:db8:2::/64 dev eth1 proto kernel metric 256 pref medium
2002:db8:1::/64 dev tun0 proto kernel metric 256 pref medium
default via 2002:db8:1::2 dev tun0 metric 1024 pref medium

$nft list ruleset
table inet filter {
        flowtable ft {
                hook ingress priority filter
                devices = { eth0, eth1 }
        }

        chain forward {
                type filter hook forward priority filter; policy accept;
                meta l4proto { tcp, udp } flow add @ft
        }
}

Fixes: b5964aac51e0 ("netfilter: flowtable: consolidate xmit path")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>