linux.git/net/netfilter, branch v7.1-rc4

netfilter: nft_ct: fix missing expect put in obj eval

2026-05-07T23:30:17+00:00

nft_ct_expect_obj_eval() allocates an expectation and may call
nf_ct_expect_related(), but never drops its local reference.

Add nf_ct_expect_put(exp) before return to balance allocation.

Fixes: 857b46027d6f ("netfilter: nft_ct: add ct expectations support")
Cc: stable@vger.kernel.org
Signed-off-by: Li Xiasong 
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_conntrack_sip: get helper before allocating expectation

2026-05-07T23:30:17+00:00

process_register_request() allocates an expectation and then checks
whether a conntrack helper is available. If helper lookup fails, the
function returns early and the allocated expectation is left behind.

Reorder the code to fetch and validate helper before calling
nf_ct_expect_alloc(). This keeps the logic simpler and removes the leak
path while preserving existing behavior.

Fixes: e14575fa7529 ("netfilter: nf_conntrack: use rcu accessors where needed")
Cc: stable@vger.kernel.org
Signed-off-by: Li Xiasong 
Signed-off-by: Pablo Neira Ayuso

netfilter: ctnetlink: check tuple and mask in expectations created via nfqueue

2026-05-07T23:30:17+00:00

Ensure the expectation tuple and mask attributes are present in netlink
message, otherwise null-ptr-deref is possible.

Fixes: bd0779370588 ("netfilter: nfnetlink_queue: allow to attach expectations to conntracks")
Signed-off-by: Pablo Neira Ayuso

netfilter: nf_conntrack_expect: restore helper propagation via expectation

2026-05-07T23:30:17+00:00

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

netfilter: x_tables: add and use xtables_unregister_table_exit

2026-05-07T23:30:16+00:00

Previous change added xtables_unregister_table_pre_exit to detach the
table from the packetpath and to unlink it from the active table list.
In case of rmmod, userspace that is doing set/getsockopt for this table
will not be able to re-instantiate the table:
 1. The larval table has been removed already
 2. existing instantiated table is no longer on the xt pernet table list.

This adds the second stage helper:

unlink the table from the dying list, free the hook ops (if any) and do
the audit notification.  It replaces xt_unregister_table().

Fixes: fdacd57c79b7 ("netfilter: x_tables: never register tables by default")
Reported-by: Tristan Madani 
Reviewed-by: Tristan Madani 
Closes: https://lore.kernel.org/netfilter-devel/20260429175613.1459342-1-tristmd@gmail.com/
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: x_tables: add and use xt_unregister_table_pre_exit

2026-05-07T23:30:16+00:00

Remove the copypasted variants of _pre_exit and add one single
function in the xtables core.  ebtables is not compatible with
x_tables and therefore unchanged.

This is a preparation patch to reduce noise in the followup
bug fixes.

Reviewed-by: Tristan Madani 
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: x_tables: allocate hook ops while under mutex

2026-05-07T23:30:16+00:00

arp/ip(6)t_register_table() add the table to the per-netns list via
xt_register_table() before allocating the per-netns hook ops copy
via kmemdup_array().  This leaves a window where the table is
visible in the list with ops=NULL.

If the pernet exit happens runs concurrently the pre_exit callback finds
the table via xt_find_table() and passes the NULL ops pointer to
nf_unregister_net_hooks(), causing a NULL dereference:

  general protection fault in nf_unregister_net_hooks+0xbc/0x150
  RIP: nf_unregister_net_hooks (net/netfilter/core.c:613)
  Call Trace:
    ipt_unregister_table_pre_exit
    iptable_mangle_net_pre_exit
    ops_pre_exit_list
    cleanup_net

Fix by moving the ops allocation into the xtables core so the table is
never in the list without valid ops.  Also ensure the table is no longer
processing packets before its torn down on error unwind.
nf_register_net_hooks might have published at least one hook; call
synchronize_rcu() if there was an error.

audit log register message gets deferred until all operations have
passed, this avoids need to emit another ureg message in case of
error unwinding.

Based on earlier patch by Tristan Madani.

Fixes: f9006acc8dfe5 ("netfilter: arp_tables: pass table pointer via nf_hook_ops")
Fixes: ee177a54413a ("netfilter: ip6_tables: pass table pointer via nf_hook_ops")
Fixes: ae689334225f ("netfilter: ip_tables: pass table pointer via nf_hook_ops")
Link: https://lore.kernel.org/netfilter-devel/20260429175613.1459342-1-tristmd@gmail.com/
Signed-off-by: Tristan Madani 
Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso

netfilter: x_tables: allow initial table replace without emitting audit log message

2026-05-07T23:30:16+00:00

At the moment we emit the audit log a bit too early, which makes it
necessary to also emit an unregister log in case we have to unwind
errors after possible hook register failure.

Followup patch will be slightly simpler if we can delay the
register message until after the hooks have been wired up.

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

ipvs: Guard access of HK_TYPE_KTHREAD cpumask with RCU

2026-05-04T23:52:55+00:00

The ip_vs_ctl.c file and the associated ip_vs.h file are the only places
in the kernel where HK_TYPE_KTHREAD cpumask is being retrieved and used.
Now that HK_TYPE_KTHREAD/HK_TYPE_DOMAIN cpumask can be changed at run
time. We need to use RCU to guard access to this cpumask to avoid a
potential UAF problem as the returned cpumask may be freed before it
is being used.

We can replace HK_TYPE_KTHREAD by HK_TYPE_DOMAIN as they are aliases
of each other, but keeping the HK_TYPE_KTHREAD name can highlight the
fact that it is the kthread initiated by ipvs that is being controlled.

Fixes: 03ff73510169 ("cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset")
Signed-off-by: Waiman Long 
Signed-off-by: Julian Anastasov 
Signed-off-by: Pablo Neira Ayuso

ipvs: fix shift-out-of-bounds in ip_vs_rht_desired_size

2026-05-04T23:52:55+00:00

Calling roundup_pow_of_two() with 0 has undefined result:

UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
shift exponent 64 is too large for 64-bit type 'unsigned long'
CPU: 1 UID: 0 PID: 77 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound conn_resize_work_handler
Call Trace:
 
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_shift_out_of_bounds+0x385/0x410 lib/ubsan.c:494
 __roundup_pow_of_two include/linux/log2.h:57 [inline]
 ip_vs_rht_desired_size+0x2cf/0x410 net/netfilter/ipvs/ip_vs_core.c:240
 ip_vs_conn_desired_size net/netfilter/ipvs/ip_vs_conn.c:765 [inline]
 conn_resize_work_handler+0x1b6/0x14c0 net/netfilter/ipvs/ip_vs_conn.c:822
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 

Reported-by: syzbot+217f1db9c791e27fe54a@syzkaller.appspotmail.com
Fixes: b655388111cf ("ipvs: add resizable hash tables")
Signed-off-by: Julian Anastasov 
Signed-off-by: Pablo Neira Ayuso