kernel/linux.git/net/netfilter/ipset, branch v6.12.107

netfilter: ipset: let destroy callbacks adjust ext mem size

2026-08-23T12:22:50+00:00

[ 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 Signed-off-by: Florian Westphal Acked-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ipset: fix list type element drift bug

2026-08-23T12:22:50+00:00

[ 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 Acked-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ipset: fix refcount race between list:set GC and swap

2026-08-23T12:22:49+00:00

[ 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: 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) 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) Acked-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ipset: switch ext_size to atomic64_t

2026-08-19T16:14:09+00:00

[ Upstream commit 712a6f545c359b427daa9a5a782e30d2f8331e25 ] The hash types do not acquire set->lock, they use 'region locking' where only part of the hash table is locked. Parallel inserts and deletes are possible and CPUs can race on ->ext_size update. Switch to atomic64_t. This leaves another bug unresolved: there still can be a race on comment extension re-init. This will be handled in a later commit when converting to rhashtable backend. Fixes: f66ee0410b1c ("netfilter: ipset: Fix "INFO: rcu detected stall in hash_xxx" reports") Signed-off-by: Jozsef Kadlecsik Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ipset: do not update comments from kernel-side hash adds

2026-08-09T18:23:14+00:00

commit f30415929be8aeb002d557c8d3f7ab2d2188003a upstream. mtype_resize() copies comment pointers with memcpy(), not the comment objects themselves. During the window after an entry has been copied but before the table swap and backlog replay, the old table is still published for packet-side updates while the replacement-table entry already holds the same ip_set_comment_rcu pointer. If xt_SET --add-set ... --exist hits that old entry in this window, mtype_add() calls ip_set_init_comment() even though packet-side adds carry no comment payload. That call frees the shared comment through the old entry, so the replacement-table entry now holds a stale pointer. When the queued add is replayed on the new table, mtype_add() calls ip_set_init_comment() again and strlen() dereferences the stale pointer. Fix this in mtype_add() by skipping ip_set_init_comment() when ext->target marks a packet-side add. Userspace adds still update comments, while packet-side adds can no longer free comment storage shared with a resize copy. Fixes: f66ee0410b1c ("netfilter: ipset: Fix "INFO: rcu detected stall in hash_xxx" reports") Cc: stable@vger.kernel.org Signed-off-by: David Lee Assisted-by: Codex:gpt-5.5 Acked-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman

netfilter: ipset: make sure gc is properly stopped

2026-07-24T14:11:12+00:00

[ Upstream commit 4a597a87e2e2f608edb6be2c510dc826b4fdfb53 ] Sashiko noticed that when destroying a set, cancel_delayed_work_sync() was called while gc calls queue_delayed_work() unconditionally which can lead not to properly shutting down the gc. Fixes: f66ee0410b1c ("netfilter: ipset: Fix "INFO: rcu detected stall in hash_xxx" reports") Signed-off-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()

2026-07-24T14:11:12+00:00

[ Upstream commit 3ca9982a8882470aa0ac4e8bb9a552b181d1efcd ] Sashiko pointed out that kfree_rcu() was called before rcu_assign_pointer() in handling the comment extension. Fix the order so that rcu_assign_pointer() called first. Fixes: b57b2d1fa53f ("netfilter: ipset: Prepare the ipset core to use RCU at set level") Signed-off-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types

2026-07-24T14:11:12+00:00

[ Upstream commit e4b4984e28c16406ecb318444dea4a8bf47def3e ] Sashiko pointed out that there are a few lockless RCU readers using test_bit() which is a relaxed atomic operation and provides no memory barrier guarantees. Use test_bit_acquire() instead where the operation may run parallel with add/del/gc, i.e. is not one from the next cases - protected by region lock - in a set destroy phase - in a new/temporary set creation phase Fixes: 18f84d41d34f ("netfilter: ipset: Introduce RCU locking in hash:* types") Signed-off-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ipset: annotate "pos" for concurrent readers/writers

2026-07-24T14:11:12+00:00

[ Upstream commit 7f7445840b7771338618930e45ee641104b38ed8 ] The "pos" structure member of struct hbucket stores the first free slot in the hash bucket of a hash type of set and there are concurrent readers/writers. Annotate accesses properly. Fixes: 18f84d41d34f ("netfilter: ipset: Introduce RCU locking in hash:* types") Signed-off-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Stable-dep-of: e4b4984e28c1 ("netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types") Signed-off-by: Sasha Levin

netfilter: ipset: Fix data race between add and dump in all hash types

2026-07-24T14:11:11+00:00

[ Upstream commit 2358f7427ccd6ec8867a48205d8fcec973683a3f ] When adding a new entry to the next position in the existing hash bucket, the position index was incremented too early and parallel dump could read it before the entry was populated with the value. Move the setting of the position index after populating the entry. v2: Position counting fixed, noticed by Florian Westphal. Fixes: 18f84d41d34f ("netfilter: ipset: Introduce RCU locking in hash:* types") Reported-by: syzbot+786c889f046e8b003ca6@syzkaller.appspotmail.com Reported-by: syzbot+1da17e4b41d795df059e@syzkaller.appspotmail.com Reported-by: syzbot+421c5f3ff8e9493084d9@syzkaller.appspotmail.com Signed-off-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Stable-dep-of: e4b4984e28c1 ("netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types") Signed-off-by: Sasha Levin