kernel/linux.git/net/netfilter, branch v5.15.219

netfilter: ipset: fix list type element drift bug

2026-08-23T12:17:31+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: flowtable: publish GC-visible tuple last

2026-08-23T12:17:31+00:00

[ 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 Assisted-by: Codex:gpt-5 Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: nf_tables_offload: suppress WARN_ON_ONCE for ENOMEM in abort path

2026-08-23T12:17:31+00:00

[ 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 Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

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

2026-08-23T12:17:31+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: nft_set_pipapo: don't leak bad clone into future transaction

2026-08-23T12:17:20+00:00

[ Upstream commit 47e65eff50691f0a5b79d325e28d83ec1da43bcf ] On memory allocation failure the cloned nft_pipapo_match can enter a bad state: - some fields can have their lookup tables resized while others did not - bits might have been toggled - scratch map can be undersized which also means m->bsize_max can be lower than what is required This means that the next insertion in the same batch can trigger out-of-bounds writes. Furthermore, a failure in the first can result in the bad clone to leak into the next transaction because the abort callback is never executed in this case (the upper layer saw an error and no attempt to allocate a transactional request was made). Record a state for the nft_pipapo_match structure: - NEW (pristine clone) - MOD (modified clone with good state) - ERR (potentially bogus content) Then make it so that deletes and insertions fail when the clone entered ERR state. In case the very first insert attempt results in an error, free the clone right away. Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges") Cc: stable@vger.kernel.org Reported-and-tested-by: Seesee Reviewed-by: Stefano Brivio Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

netfilter: nft_set_pipapo: move cloning of match info to insert/removal path

2026-08-23T12:17:20+00:00

[ Upstream commit 3f1d886cc7c3525d4dbeee24bfa9bb3fe0d48ddc ] This set type keeps two copies of the sets' content, priv->match (live version, used to match from packet path) priv->clone (work-in-progress version of the 'future' priv->match). All additions and removals are done on priv->clone. When transaction completes, priv->clone becomes priv->match and a new clone is allocated for use by next transaction. Problem is that the cloning requires GFP_KERNEL allocations but we cannot fail at either commit or abort time. This patch defers the clone until we get an insertion or removal request. This allows us to handle OOM situations correctly. This also allows to remove ->dirty in a followup change: If ->clone exists, ->dirty is always true If ->clone is NULL, ->dirty is always false, no elements were added or removed (except catchall elements which are external to the specific set backend). Signed-off-by: Florian Westphal Reviewed-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso Stable-dep-of: 47e65eff5069 ("netfilter: nft_set_pipapo: don't leak bad clone into future transaction") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

netfilter: nft_set_pipapo: prepare pipapo_get helper for on-demand clone

2026-08-23T12:17:20+00:00

[ Upstream commit a238106703ab4ae1090b86eba128815b8626d8f1 ] The helper uses priv->clone unconditionally which will fail once we do the clone conditionally on first insert or removal. 'nft get element' from userspace needs to use priv->match since this runs from rcu read side lock section. Prepare for this by passing the match backend data as argument. Signed-off-by: Florian Westphal Reviewed-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso Stable-dep-of: 47e65eff5069 ("netfilter: nft_set_pipapo: don't leak bad clone into future transaction") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

netfilter: nft_set_pipapo: merge deactivate helper into caller

2026-08-23T12:17:20+00:00

[ Upstream commit c5444786d0ea2417a5e2cee7bd67137fc8bad687 ] Its the only remaining call site so there is no need for this to be separated anymore. Signed-off-by: Florian Westphal Reviewed-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso Stable-dep-of: 47e65eff5069 ("netfilter: nft_set_pipapo: don't leak bad clone into future transaction") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

netfilter: nft_set_pipapo: prepare walk function for on-demand clone

2026-08-23T12:17:20+00:00

[ Upstream commit 6c108d9bee448a850b03e682836bfe91fca645cb ] The existing code uses iter->type to figure out what data is needed, the live copy (READ) or clone (UPDATE). Without pending updates, priv->clone and priv->match will point to different memory locations, but they have identical content. Future patch will make priv->clone == NULL if there are no pending changes, in this case we must copy the live data for the UPDATE case. Currently this would require GFP_ATOMIC allocation. Split the walk function in two parts: one that does the walk and one that decides which data is needed. In the UPDATE case, callers hold the transaction mutex so we do not need the rcu read lock. This allows to use GFP_KERNEL allocation while cloning. Signed-off-by: Florian Westphal Reviewed-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso Stable-dep-of: 47e65eff5069 ("netfilter: nft_set_pipapo: don't leak bad clone into future transaction") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

netfilter: nft_set_pipapo: make pipapo_clone helper return NULL

2026-08-23T12:17:20+00:00

[ Upstream commit 80efd2997fb9343a0283cf3cac5524a4595c8ff4 ] Currently it returns an error pointer, but the only possible failure is ENOMEM. After a followup patch, we'd need to discard the errno code, i.e. x = pipapo_clone() if (IS_ERR(x)) return NULL or make more changes to fix up callers to expect IS_ERR() code from set->ops->deactivate(). So simplify this and make it return ptr-or-null. Signed-off-by: Florian Westphal Reviewed-by: Stefano Brivio Signed-off-by: Pablo Neira Ayuso Stable-dep-of: 47e65eff5069 ("netfilter: nft_set_pipapo: don't leak bad clone into future transaction") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman