linux-stable.git/net/bridge, branch v7.2

netfilter: bridge: release template ct on non-IP path

2026-08-10T18:14:01+00:00

A bridge nftables ct zone set rule can attach a conntrack template to
an skb before nf_ct_bridge_pre() sees it. For non-IPv4 and non-IPv6
EtherTypes, nf_ct_bridge_pre() currently overwrites skb->_nfct with
IP_CT_UNTRACKED without releasing the existing template reference.

That makes the per-cpu template, and any temporary templates allocated
for concurrent use, unreachable and leaks memory until the host runs out
of slab.

Reset the skb conntrack state before marking the frame untracked so the
existing template reference is dropped on the non-IP path.

Fixes: 3c171f496ef5 ("netfilter: bridge: add connection tracking system")
Cc: stable@vger.kernel.org
Reported-by: Vega 
Signed-off-by: Zhiling Zou 
Signed-off-by: Pablo Neira Ayuso

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

2026-08-05T23:23:34+00:00

Partial pull of the nf-26-07-31 tag

Pablo says:

====================
The following patchset contains Netfilter/IPVS fixes net, this
includes fixes for ebtables nflog target, ipset hash type,
IPVS kthread estimator

1) Prevent IPVS kthread estimator from draining the est_temp_list
   when netns is being dismantled. From Zhiling Zou.

2) Missing module nflog refcount bump from ebtables nflog target from
   .checkentry path. Similar dependency exists already in xt_NFLOG and
   nft_log. From Chengfeng Ye.

3) Use RCU to fix ipset bookkeeping of cidr values on weakly-ordered
   architectures. From Jozsef Kadlecsik.

4) Use atomic64_t for set->ext_size in ipset to fix parallel inserts
   and deletes racing on updating it. From Jozsef Kadlecsik.

5) Add small wrappers for hash and bucket size to prepare the update
   of ipset hash set types to rhashtable, from Florian Westphal.

6) Add mtype_del_cidr_all() and use it to prepare the migration of
   ipset hash types to rhashtable. From Florian Westphal.

7) Replace existing ipset call_rcu() based destruction with rcu_work
   api also to ease the transition to rhashtable. Also from Florian.

8) Avoid reading the IPv4 ihl field multiple times to prevent local
   attacker to cause out-of-bounds write in ip_vs_nat_icmp(), from
   Julian Anastasov.

9) Restore the checksum validations that could be needed by the IPVS
   FORWARD hook. Also from Julian.
====================

Link: https://patch.msgid.link/20260731151806.849724-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski

net: bridge: mrp: fix uninitialised bytes on the wire

2026-07-31T23:31:16+00:00

br_mrp_alloc_test_skb() builds MRP test frames on an skb from
dev_alloc_skb(), which does not clear the linear data area.  On the MRA
ring-role branch the sub-option TLV header is appended with

	sub_tlv = skb_put(skb, sizeof(*sub_tlv));
	sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR;

so sub_tlv->length is never written, and the two trailing alignment bytes
are appended with a bare skb_put() that does not clear them either.  The
neighbouring oui and sub_opt regions are explicitly zeroed, so three
uninitialised bytes are left in every MRA MRP_Test frame that goes out.

Put the sub-option TLV header and the alignment padding in a single
skb_put_zero(), which clears both.  The AUTO_MGR sub-TLV carries no
payload, so the zeroed length field is already the value it should have.

Fixes: f7458934b079 ("net: bridge: mrp: Update the Test frames for MRA")
Suggested-by: Nikolay Aleksandrov 
Cc: stable@vger.kernel.org
Signed-off-by: Baul Lee 
Acked-by: Nikolay Aleksandrov 
Link: https://patch.msgid.link/20260729131941.10254-1-baul.lee@xbow.com
Signed-off-by: Jakub Kicinski

netfilter: ebt_nflog: pin the NFLOG backend

2026-07-31T13:56:41+00:00

nf_log_unregister() runs after the per-net teardown so its final RCU
grace period also drains readers that obtained the logger from a per-net
binding.  However, ebt_nflog passes an explicit ULOG log type to
nf_log_packet() without holding a reference on the selected logger module,
unlike the xt_NFLOG and nft_log frontends.

An ebtables nflog rule can therefore remain callable while nfnetlink_log
is unloaded.  The resulting interleaving is:

  CPU 0                               CPU 1
  nfnetlink_log_fini()
    unregister_pernet_subsys()
      kfree(nfnl_log_pernet(net))
                                      ebt_nflog_tg()
                                        nf_log_packet()
                                          nfulnl_log_packet()
                                            instance_lookup_get_rcu()

The global ULOG logger is still registered at this point, so CPU 1
dereferences the per-net state after CPU 0 has freed it.  KASAN reported:

  BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu
  Read of size 8 at addr ff110001052e6210 by task poc/92
  Call Trace:
   instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log]
   nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log]
   nf_log_packet+0x204/0x300
   ebt_nflog_tg+0x351/0x550
   ebt_do_table+0xedf/0x22b0
  Allocated by task 90:
   __kmalloc_noprof+0x186/0x470
   ops_init+0x6d/0x420
   register_pernet_operations+0x2f6/0x670
   register_pernet_subsys+0x23/0x40
  Freed by task 93:
   kfree+0x131/0x3c0
   ops_undo_list+0x3e3/0x700
   unregister_pernet_operations+0x232/0x490
   unregister_pernet_subsys+0x1c/0x30
   nfnetlink_log_fini+0x34/0x450 [nfnetlink_log]

Acquire the ULOG logger module reference when an ebt_nflog rule is
validated and release it when the rule is destroyed.  Request the NFLOG
backend for legacy callers when needed, matching xt_NFLOG.  This prevents
module teardown until all ebt_nflog rules have stopped using the logger.

Fixes: c83fa19603bd ("netfilter: nf_log: don't call synchronize_rcu in nf_log_unset")
Cc: stable@vger.kernel.org
Signed-off-by: Chengfeng Ye 
Signed-off-by: Pablo Neira Ayuso

net: bridge: mrp: fix Option TLV length in MRP_Test frames

2026-07-27T22:56:55+00:00

oui is a pointer, so sizeof(oui) is the pointer size. The MRA
Option TLV thus advertises a wrong length (15 vs 10 on x86_64),
causing misparsing of the frame on peers. Fix is to replace
with sizeof(*oui).

Fixes: f7458934b079 ("net: bridge: mrp: Update the Test frames for MRA")
Signed-off-by: David Corvaglia 
Acked-by: Nikolay Aleksandrov 
Link: https://patch.msgid.link/20260726062605.2746-1-david@corvaglia.dev
Signed-off-by: Jakub Kicinski

net: bridge: stop fast-leave after deleting a port group

2026-07-27T22:20:27+00:00

br_multicast_leave_group() iterates mp->ports with pp = &p->next in
its fast-leave path. After br_multicast_del_pg() removes p,
continuing the loop advances pp through the deleted entry.

If multicast-to-unicast was enabled, the bridge can hold multiple port
groups for the same port and group with different source MAC
addresses. Once multicast-to-unicast is disabled,
br_port_group_equal() matches those entries by port only. A fast leave
can then delete one entry and continue from its stale next pointer,
leaving mp->ports pointing at a deleted port group.

Fast leave only needs to remove one matching port group. Break after
br_multicast_del_pg() so the loop stops before dereferencing the
removed entry.

Fixes: 6db6f0eae605 ("bridge: multicast to unicast")
Cc: stable@vger.kernel.org
Reported-by: Vega 
Signed-off-by: Zhiling Zou 
Signed-off-by: Ren Wei 
Acked-by: Nikolay Aleksandrov 
Link: https://patch.msgid.link/1cf0898872ef7c72d5f4c0304414a192c6dac591.1784707712.git.zhilinz@nebusec.ai
Signed-off-by: Jakub Kicinski

net: bridge: vlan: fix vlan range dumps starting with pvid

2026-07-22T17:23:18+00:00

There is a bug in all range dumps that rely on br_vlan_can_enter_range()
when the PVID is a range starting VLAN, all following VLANs that match
its flags can enter the range, but when the range is filled in only the
PVID VLAN is dumped and the rest of the range is discarded because
br_vlan_fill_vids() checks for the PVID flag. Since the PVID VLAN can
be only one, we need to break ranges around it, the best way to do that
consistently for all is to alter br_vlan_can_enter_range() to take into
account the PVID and return false to break the range when it's matched.

Before the fix:
$ ip l add br0 type bridge vlan_filtering 1
$ ip l add dumdum type dummy
$ ip l set dumdum master br0
$ ip l set br0 up
$ ip l set dumdum up
$ bridge vlan add dev dumdum vid 1 pvid untagged master
$ bridge vlan add dev dumdum vid 2 untagged master
$ bridge vlan show dev dumdum # use legacy dump to show all vlans
port              vlan-id
dumdum            1 PVID Egress Untagged
                  2 Egress Untagged

$ bridge -d vlan show dev dumdum # use the new dump (RTM_GETVLAN)
port              vlan-id
dumdum            1 PVID Egress Untagged
                    state forwarding mcast_router 1

VLAN 2 is missing, and if there are more matching VLANs afterwards
they'd be missing too.

After the fix:
[ same setup steps ]
$ bridge vlan show dev dumdum
port              vlan-id
dumdum            1 PVID Egress Untagged
                  2 Egress Untagged
$ bridge -d vlan show dev dumdum # use the new dump (RTM_GETVLAN)
port              vlan-id
dumdum            1 PVID Egress Untagged
                    state forwarding mcast_router 1
                  2 Egress Untagged
                    state forwarding mcast_router 1

Fixes: 0ab558795184 ("net: bridge: vlan: add rtm range support")
Signed-off-by: Nikolay Aleksandrov 
Reviewed-by: Ido Schimmel 
Link: https://patch.msgid.link/20260721140922.682265-2-razor@blackwall.org
Signed-off-by: Jakub Kicinski

netfilter: ebtables: module names must be null-terminated

2026-07-08T13:22:03+00:00

We need to explicitly check the length, else we may pass non-null
terminated string to request_module().

Cc: stable@vger.kernel.org
Fixes: bcf493428840 ("netfilter: ebtables: Fix extension lookup with identical name")
Signed-off-by: Florian Westphal

netfilter: ebtables: zero chainstack array

2026-07-08T13:22:03+00:00

sashiko reports:
 looking at ebtables table
 translation, could a sparse cpu_possible_mask lead to an uninitialized pointer
 free?

 If cpu_possible_mask is sparse (for example, CPU 0 and CPU 2 are possible,
 but CPU 1 is not), the allocation loop skips CPU 1. If vmalloc_node() fails at
 CPU 2, the cleanup loop will blindly decrement and call vfree() on
 newinfo->chainstack[1].

Not a real-world bug, such allocation isn't expected to fail
in the first place.

Cc: stable@vger.kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Florian Westphal

netfilter: ebtables: terminate table name before find_table_lock()

2026-07-08T13:22:03+00:00

update_counters() and compat_update_counters() forward a user-supplied
32-byte table name to find_table_lock() without NUL-terminating it. On a
lookup miss, find_inlist_lock() calls try_then_request_module(..., "%s%s",
"ebtable_", name), and vsnprintf() reads past the name field and the
stack object until it hits a zero byte.

  BUG: KASAN: stack-out-of-bounds in string (lib/vsprintf.c:648 lib/vsprintf.c:730)
  Read of size 1 at addr ffff8880119dfb20 by task exploit/147
  Call Trace:
  ...
   string (lib/vsprintf.c:648 lib/vsprintf.c:730)
   vsnprintf (lib/vsprintf.c:2945)
   __request_module (kernel/module/kmod.c:150)
   do_update_counters.isra.0 (net/bridge/netfilter/ebtables.c:371 net/bridge/netfilter/ebtables.c:380)
   update_counters (net/bridge/netfilter/ebtables.c:1440)
   do_ebt_set_ctl (net/bridge/netfilter/ebtables.c:2573)
   nf_setsockopt (net/netfilter/nf_sockopt.c:101)
   ip_setsockopt (net/ipv4/ip_sockglue.c:1424)
   raw_setsockopt (net/ipv4/raw.c:847)
   __sys_setsockopt (net/socket.c:2393)
  ...

compat_do_replace() shares the same unterminated name via
compat_copy_ebt_replace_from_user(); terminate it there too so all
find_table_lock() callers behave alike. The other callers already
terminate the name after the copy.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: 81e675c227ec ("netfilter: ebtables: add CONFIG_COMPAT support")
Cc: stable@vger.kernel.org
Reported-by: Weiming Shi 
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Xiang Mei 
Signed-off-by: Florian Westphal