linux-stable.git/include/net, branch linux-6.12.y

wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure

2026-04-27T13:24:24+00:00

[ Upstream commit d5ad6ab61cbd89afdb60881f6274f74328af3ee9 ]

ieee80211_tx_prepare_skb() has three error paths, but only two of them
free the skb. The first error path (ieee80211_tx_prepare() returning
TX_DROP) does not free it, while invoke_tx_handlers() failure and the
fragmentation check both do.

Add kfree_skb() to the first error path so all three are consistent,
and remove the now-redundant frees in callers (ath9k, mt76,
mac80211_hwsim) to avoid double-free.

Document the skb ownership guarantee in the function's kdoc.

Signed-off-by: Felix Fietkau 
Link: https://patch.msgid.link/20260314065455.2462900-1-nbd@nbd.name
Fixes: 06be6b149f7e ("mac80211: add ieee80211_tx_prepare_skb() helper function")
Signed-off-by: Johannes Berg 
[ Exclude changes to drivers/net/wireless/mediatek/mt76/scan.c as this file is first
 introduced by commit 31083e38548f("wifi: mt76: add code for emulating hardware scanning")
 after linux-6.14.]
Signed-off-by: Li hongliang <1468888505@139.com>
Signed-off-by: Sasha Levin

net: sched: fix TCF_LAYER_TRANSPORT handling in tcf_get_base_ptr()

2026-04-22T11:19:01+00:00

[Upstream commit 4fe5a00ec70717a7f1002d8913ec6143582b3c8e]

syzbot reported that tcf_get_base_ptr() can be called while transport
header is not set [1].

Instead of returning a dangling pointer, return NULL.

Fix tcf_get_base_ptr() callers to handle this NULL value.

[1]
 WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 skb_transport_header include/linux/skbuff.h:3071 [inline]
 WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 tcf_get_base_ptr include/net/pkt_cls.h:539 [inline]
 WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 em_nbyte_match+0x2d8/0x3f0 net/sched/em_nbyte.c:43
Modules linked in:
CPU: 1 UID: 0 PID: 6019 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Call Trace:
 
  tcf_em_match net/sched/ematch.c:494 [inline]
  __tcf_em_tree_match+0x1ac/0x770 net/sched/ematch.c:520
  tcf_em_tree_match include/net/pkt_cls.h:512 [inline]
  basic_classify+0x115/0x2d0 net/sched/cls_basic.c:50
  tc_classify include/net/tc_wrapper.h:197 [inline]
  __tcf_classify net/sched/cls_api.c:1764 [inline]
  tcf_classify+0x4cf/0x1140 net/sched/cls_api.c:1860
  multiq_classify net/sched/sch_multiq.c:39 [inline]
  multiq_enqueue+0xfd/0x4c0 net/sched/sch_multiq.c:66
  dev_qdisc_enqueue+0x4e/0x260 net/core/dev.c:4118
  __dev_xmit_skb net/core/dev.c:4214 [inline]
  __dev_queue_xmit+0xe83/0x3b50 net/core/dev.c:4729
  packet_snd net/packet/af_packet.c:3076 [inline]
  packet_sendmsg+0x3e33/0x5080 net/packet/af_packet.c:3108
  sock_sendmsg_nosec net/socket.c:727 [inline]
  __sock_sendmsg+0x21c/0x270 net/socket.c:742
  ____sys_sendmsg+0x505/0x830 net/socket.c:2630

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+f3a497f02c389d86ef16@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6920855a.a70a0220.2ea503.0058.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet 
Reviewed-by: Jamal Hadi Salim 
Link: https://patch.msgid.link/20251121154100.1616228-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Chelsy Ratnawat 
Signed-off-by: Sasha Levin

netfilter: nfnetlink_queue: make hash table per queue

2026-04-22T11:18:54+00:00

[ Upstream commit 936206e3f6ff411581e615e930263d6f8b78df9d ]

Sharing a global hash table among all queues is tempting, but
it can cause crash:

BUG: KASAN: slab-use-after-free in nfqnl_recv_verdict+0x11ac/0x15e0 [nfnetlink_queue]
[..]
 nfqnl_recv_verdict+0x11ac/0x15e0 [nfnetlink_queue]
 nfnetlink_rcv_msg+0x46a/0x930
 kmem_cache_alloc_node_noprof+0x11e/0x450

struct nf_queue_entry is freed via kfree, but parallel cpu can still
encounter such an nf_queue_entry when walking the list.

Alternative fix is to free the nf_queue_entry via kfree_rcu() instead,
but as we have to alloc/free for each skb this will cause more mem
pressure.

Cc: Scott Mitchell 
Fixes: e19079adcd26 ("netfilter: nfnetlink_queue: optimize verdict lookup with hash table")
Signed-off-by: Florian Westphal 
Signed-off-by: Sasha Levin

xsk: fix XDP_UMEM_SG_FLAG issues

2026-04-22T11:18:53+00:00

[ Upstream commit 93e84fe45b752d17a5a46b306ed78f0133bbc719 ]

Currently xp_assign_dev_shared() is missing XDP_USE_SG being propagated
to flags so set it in order to preserve mtu check that is supposed to be
done only when no multi-buffer setup is in picture.

Also, this flag has the same value as XDP_UMEM_TX_SW_CSUM so we could
get unexpected SG setups for software Tx checksums. Since csum flag is
UAPI, modify value of XDP_UMEM_SG_FLAG.

Fixes: d609f3d228a8 ("xsk: add multi-buffer support for sockets sharing umem")
Reviewed-by: Björn Töpel 
Signed-off-by: Maciej Fijalkowski 
Link: https://patch.msgid.link/20260402154958.562179-4-maciej.fijalkowski@intel.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

xsk: respect tailroom for ZC setups

2026-04-22T11:18:53+00:00

[ Upstream commit 1ee1605138fc94cc8f8f273321dd2471c64977f9 ]

Multi-buffer XDP stores information about frags in skb_shared_info that
sits at the tailroom of a packet. The storage space is reserved via
xdp_data_hard_end():

	((xdp)->data_hard_start + (xdp)->frame_sz -	\
	 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))

and then we refer to it via macro below:

static inline struct skb_shared_info *
xdp_get_shared_info_from_buff(const struct xdp_buff *xdp)
{
        return (struct skb_shared_info *)xdp_data_hard_end(xdp);
}

Currently we do not respect this tailroom space in multi-buffer AF_XDP
ZC scenario. To address this, introduce xsk_pool_get_tailroom() and use
it within xsk_pool_get_rx_frame_size() which is used in ZC drivers to
configure length of HW Rx buffer.

Typically drivers on Rx Hw buffers side work on 128 byte alignment so
let us align the value returned by xsk_pool_get_rx_frame_size() in order
to avoid addressing this on driver's side. This addresses the fact that
idpf uses mentioned function *before* pool->dev being set so we were at
risk that after subtracting tailroom we would not provide 128-byte
aligned value to HW.

Since xsk_pool_get_rx_frame_size() is actively used in xsk_rcv_check()
and __xsk_rcv(), add a variant of this routine that will not include 128
byte alignment and therefore old behavior is preserved.

Reviewed-by: Björn Töpel 
Acked-by: Stanislav Fomichev 
Fixes: 24ea50127ecf ("xsk: support mbuf on ZC RX")
Signed-off-by: Maciej Fijalkowski 
Link: https://patch.msgid.link/20260402154958.562179-3-maciej.fijalkowski@intel.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: increase IP_TUNNEL_RECURSION_LIMIT to 5

2026-04-22T11:18:52+00:00

[ Upstream commit 77facb35227c421467cdb49268de433168c2dcef ]

In configurations with multiple tunnel layers and MPLS lwtunnel routing, a
single tunnel hop can increment the counter beyond this limit. This causes
packets to be dropped with the "Dead loop on virtual device" message even
when a routing loop doesn't exist.

Increase IP_TUNNEL_RECURSION_LIMIT from 4 to 5 to handle this use-case.

Fixes: 6f1a9140ecda ("net: add xmit recursion limit to tunnel xmit functions")
Link: https://lore.kernel.org/netdev/88deb91b-ef1b-403c-8eeb-0f971f27e34f@redhat.com/
Signed-off-by: Chris J Arges 
Link: https://patch.msgid.link/20260402222401.3408368-1-carges@cloudflare.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netfilter: nft_ct: fix use-after-free in timeout object destroy

2026-04-18T08:41:56+00:00

commit f8dca15a1b190787bbd03285304b569631160eda upstream.

nft_ct_timeout_obj_destroy() frees the timeout object with kfree()
immediately after nf_ct_untimeout(), without waiting for an RCU grace
period. Concurrent packet processing on other CPUs may still hold
RCU-protected references to the timeout object obtained via
rcu_dereference() in nf_ct_timeout_data().

Add an rcu_head to struct nf_ct_timeout and use kfree_rcu() to defer
freeing until after an RCU grace period, matching the approach already
used in nfnetlink_cttimeout.c.

KASAN report:
 BUG: KASAN: slab-use-after-free in nf_conntrack_tcp_packet+0x1381/0x29d0
 Read of size 4 at addr ffff8881035fe19c by task exploit/80

 Call Trace:
  nf_conntrack_tcp_packet+0x1381/0x29d0
  nf_conntrack_in+0x612/0x8b0
  nf_hook_slow+0x70/0x100
  __ip_local_out+0x1b2/0x210
  tcp_sendmsg_locked+0x722/0x1580
  __sys_sendto+0x2d8/0x320

 Allocated by task 75:
  nft_ct_timeout_obj_init+0xf6/0x290
  nft_obj_init+0x107/0x1b0
  nf_tables_newobj+0x680/0x9c0
  nfnetlink_rcv_batch+0xc29/0xe00

 Freed by task 26:
  nft_obj_destroy+0x3f/0xa0
  nf_tables_trans_destroy_work+0x51c/0x5c0
  process_one_work+0x2c4/0x5a0

Fixes: 7e0b2b57f01d ("netfilter: nft_ct: add ct timeout support")
Cc: stable@vger.kernel.org
Signed-off-by: Tuan Do 
Signed-off-by: Florian Westphal 
Signed-off-by: Greg Kroah-Hartman

netfilter: nf_conntrack_expect: store netns and zone in expectation

2026-04-11T12:24:35+00:00

[ Upstream commit 02a3231b6d82efe750da6554ebf280e4a6f78756 ]

__nf_ct_expect_find() and nf_ct_expect_find_get() are called under
rcu_read_lock() but they dereference the master conntrack via
exp->master.

Since the expectation does not hold a reference on the master conntrack,
this could be dying conntrack or different recycled conntrack than the
real master due to SLAB_TYPESAFE_RCU.

Store the netns, the master_tuple and the zone in struct
nf_conntrack_expect as a safety measure.

This patch is required by the follow up fix not to dump expectations
that do not belong to this netns.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Stable-dep-of: 917b61fa2042 ("netfilter: ctnetlink: ignore explicit helper on new expectations")
Signed-off-by: Sasha Levin

netfilter: nf_conntrack_expect: honor expectation helper field

2026-04-11T12:24:34+00:00

[ Upstream commit 9c42bc9db90a154bc61ae337a070465f3393485a ]

The expectation helper field is mostly unused. As a result, the
netfilter codebase relies on accessing the helper through exp->master.

Always set on the expectation helper field so it can be used to reach
the helper.

nf_ct_expect_init() is called from packet path where the skb owns
the ct object, therefore accessing exp->master for the newly created
expectation is safe. This saves a lot of updates in all callsites
to pass the ct object as parameter to nf_ct_expect_init().

This is a preparation patches for follow up fixes.

Signed-off-by: Florian Westphal 
Signed-off-by: Pablo Neira Ayuso 
Stable-dep-of: 917b61fa2042 ("netfilter: ctnetlink: ignore explicit helper on new expectations")
Signed-off-by: Sasha Levin

udp: Fix wildcard bind conflict check when using hash2

2026-04-02T11:09:35+00:00

[ Upstream commit e537dd15d0d4ad989d56a1021290f0c674dd8b28 ]

When binding a udp_sock to a local address and port, UDP uses
two hashes (udptable->hash and udptable->hash2) for collision
detection. The current code switches to "hash2" when
hslot->count > 10.

"hash2" is keyed by local address and local port.
"hash" is keyed by local port only.

The issue can be shown in the following bind sequence (pseudo code):

bind(fd1,  "[fd00::1]:8888")
bind(fd2,  "[fd00::2]:8888")
bind(fd3,  "[fd00::3]:8888")
bind(fd4,  "[fd00::4]:8888")
bind(fd5,  "[fd00::5]:8888")
bind(fd6,  "[fd00::6]:8888")
bind(fd7,  "[fd00::7]:8888")
bind(fd8,  "[fd00::8]:8888")
bind(fd9,  "[fd00::9]:8888")
bind(fd10, "[fd00::10]:8888")

/* Correctly return -EADDRINUSE because "hash" is used
 * instead of "hash2". udp_lib_lport_inuse() detects the
 * conflict.
 */
bind(fail_fd, "[::]:8888")

/* After one more socket is bound to "[fd00::11]:8888",
 * hslot->count exceeds 10 and "hash2" is used instead.
 */
bind(fd11, "[fd00::11]:8888")
bind(fail_fd, "[::]:8888")      /* succeeds unexpectedly */

The same issue applies to the IPv4 wildcard address "0.0.0.0"
and the IPv4-mapped wildcard address "::ffff:0.0.0.0". For
example, if there are existing sockets bound to
"192.168.1.[1-11]:8888", then binding "0.0.0.0:8888" or
"[::ffff:0.0.0.0]:8888" can also miss the conflict when
hslot->count > 10.

TCP inet_csk_get_port() already has the correct check in
inet_use_bhash2_on_bind(). Rename it to
inet_use_hash2_on_bind() and move it to inet_hashtables.h
so udp.c can reuse it in this fix.

Fixes: 30fff9231fad ("udp: bind() optimisation")
Reported-by: Andrew Onyshchuk 
Signed-off-by: Martin KaFai Lau 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20260319181817.1901357-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin