linux.git/include/net, branch v6.18.21

Bluetooth: L2CAP: Fix regressions caused by reusing ident

2026-04-02T11:23:33+00:00

commit 761fb8ec8778f0caf2bba5a41e3cff1ea86974f3 upstream.

This attempt to fix regressions caused by reusing ident which apparently
is not handled well on certain stacks causing the stack to not respond to
requests, so instead of simple returning the first unallocated id this
stores the last used tx_ident and then attempt to use the next until all
available ids are exausted and then cycle starting over to 1.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=221120
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221177
Fixes: 6c3ea155e5ee ("Bluetooth: L2CAP: Fix not tracking outstanding TX ident")
Signed-off-by: Luiz Augusto von Dentz 
Tested-by: Christian Eggers 
Signed-off-by: Greg Kroah-Hartman

Bluetooth: L2CAP: Fix not tracking outstanding TX ident

2026-04-02T11:23:08+00:00

[ Upstream commit 6c3ea155e5ee3e56606233acde8309afda66d483 ]

This attempts to proper track outstanding request by using struct ida
and allocating from it in l2cap_get_ident using ida_alloc_range which
would reuse ids as they are free, then upon completion release
the id using ida_free.

This fixes the qualification test case L2CAP/COS/CED/BI-29-C which
attempts to check if the host stack is able to work after 256 attempts
to connect which requires Ident field to use the full range of possible
values in order to pass the test.

Link: https://github.com/bluez/bluez/issues/1829
Signed-off-by: Luiz Augusto von Dentz 
Reviewed-by: Paul Menzel 
Stable-dep-of: 00fdebbbc557 ("Bluetooth: L2CAP: Fix deadlock in l2cap_conn_del()")
Signed-off-by: Sasha Levin

udp: Fix wildcard bind conflict check when using hash2

2026-04-02T11:23:07+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

ipv6: Don't remove permanent routes with exceptions from tb6_gc_hlist.

2026-04-02T11:23:07+00:00

[ Upstream commit 4be7b99c253f0c85a255cc1db7127ba3232dfa30 ]

The cited commit mechanically put fib6_remove_gc_list()
just after every fib6_clean_expires() call.

When a temporary route is promoted to a permanent route,
there may already be exception routes tied to it.

If fib6_remove_gc_list() removes the route from tb6_gc_hlist,
such exception routes will no longer be aged.

Let's replace fib6_remove_gc_list() with a new helper
fib6_may_remove_gc_list() and use fib6_age_exceptions() there.

Note that net->ipv6 is only compiled when CONFIG_IPV6 is
enabled, so fib6_{add,remove,may_remove}_gc_list() are guarded.

Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.")
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20260320072317.2561779-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n

2026-03-25T10:10:42+00:00

[ Upstream commit b3a6df291fecf5f8a308953b65ca72b7fc9e015d ]

When CONFIG_IPV6 is disabled, the udp_sock_create6() function returns 0
(success) without actually creating a socket. Callers such as
fou_create() then proceed to dereference the uninitialized socket
pointer, resulting in a NULL pointer dereference.

The captured NULL deref crash:
  BUG: kernel NULL pointer dereference, address: 0000000000000018
  RIP: 0010:fou_nl_add_doit (net/ipv4/fou_core.c:590 net/ipv4/fou_core.c:764)
  [...]
  Call Trace:
    
    genl_family_rcv_msg_doit.constprop.0 (net/netlink/genetlink.c:1114)
    genl_rcv_msg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209)
    [...]
    netlink_rcv_skb (net/netlink/af_netlink.c:2550)
    genl_rcv (net/netlink/genetlink.c:1219)
    netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)
    netlink_sendmsg (net/netlink/af_netlink.c:1894)
    __sock_sendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1))
    __sys_sendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1))
    __x64_sys_sendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1))
    do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
    entry_SYSCALL_64_after_hwframe (net/arch/x86/entry/entry_64.S:130)

This patch makes udp_sock_create6 return -EPFNOSUPPORT instead, so
callers correctly take their error paths. There is only one caller of
the vulnerable function and only privileged users can trigger it.

Fixes: fd384412e199b ("udp_tunnel: Seperate ipv6 functions into its own file.")
Reported-by: Weiming Shi 
Signed-off-by: Xiang Mei 
Link: https://patch.msgid.link/20260317010241.1893893-1-xmei5@asu.edu
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

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

2026-03-25T10:10:42+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 
Signed-off-by: Sasha Levin

clsact: Fix use-after-free in init/destroy rollback asymmetry

2026-03-25T10:10:41+00:00

[ Upstream commit a0671125d4f55e1e98d9bde8a0b671941987e208 ]

Fix a use-after-free in the clsact qdisc upon init/destroy rollback asymmetry.
The latter is achieved by first fully initializing a clsact instance, and
then in a second step having a replacement failure for the new clsact qdisc
instance. clsact_init() initializes ingress first and then takes care of the
egress part. This can fail midway, for example, via tcf_block_get_ext(). Upon
failure, the kernel will trigger the clsact_destroy() callback.

Commit 1cb6f0bae504 ("bpf: Fix too early release of tcx_entry") details the
way how the transition is happening. If tcf_block_get_ext on the q->ingress_block
ends up failing, we took the tcx_miniq_inc reference count on the ingress
side, but not yet on the egress side. clsact_destroy() tests whether the
{ingress,egress}_entry was non-NULL. However, even in midway failure on the
replacement, both are in fact non-NULL with a valid egress_entry from the
previous clsact instance.

What we really need to test for is whether the qdisc instance-specific ingress
or egress side previously got initialized. This adds a small helper for checking
the miniq initialization called mini_qdisc_pair_inited, and utilizes that upon
clsact_destroy() in order to fix the use-after-free scenario. Convert the
ingress_destroy() side as well so both are consistent to each other.

Fixes: 1cb6f0bae504 ("bpf: Fix too early release of tcx_entry")
Reported-by: Keenan Dong 
Signed-off-by: Daniel Borkmann 
Cc: Martin KaFai Lau 
Acked-by: Martin KaFai Lau 
Link: https://patch.msgid.link/20260313065531.98639-1-daniel@iogearbox.net
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net/sched: teql: Fix double-free in teql_master_xmit

2026-03-25T10:10:41+00:00

[ Upstream commit 66360460cab63c248ca5b1070a01c0c29133b960 ]

Whenever a TEQL devices has a lockless Qdisc as root, qdisc_reset should
be called using the seq_lock to avoid racing with the datapath. Failure
to do so may cause crashes like the following:

[  238.028993][  T318] BUG: KASAN: double-free in skb_release_data (net/core/skbuff.c:1139)
[  238.029328][  T318] Free of addr ffff88810c67ec00 by task poc_teql_uaf_ke/318
[  238.029749][  T318]
[  238.029900][  T318] CPU: 3 UID: 0 PID: 318 Comm: poc_teql_ke Not tainted 7.0.0-rc3-00149-ge5b31d988a41 #704 PREEMPT(full)
[  238.029906][  T318] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  238.029910][  T318] Call Trace:
[  238.029913][  T318]  
[  238.029916][  T318]  dump_stack_lvl (lib/dump_stack.c:122)
[  238.029928][  T318]  print_report (mm/kasan/report.c:379 mm/kasan/report.c:482)
[  238.029940][  T318]  ? skb_release_data (net/core/skbuff.c:1139)
[  238.029944][  T318]  ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
...
[  238.029957][  T318]  ? skb_release_data (net/core/skbuff.c:1139)
[  238.029969][  T318]  kasan_report_invalid_free (mm/kasan/report.c:221 mm/kasan/report.c:563)
[  238.029979][  T318]  ? skb_release_data (net/core/skbuff.c:1139)
[  238.029989][  T318]  check_slab_allocation (mm/kasan/common.c:231)
[  238.029995][  T318]  kmem_cache_free (mm/slub.c:2637 (discriminator 1) mm/slub.c:6168 (discriminator 1) mm/slub.c:6298 (discriminator 1))
[  238.030004][  T318]  skb_release_data (net/core/skbuff.c:1139)
...
[  238.030025][  T318]  sk_skb_reason_drop (net/core/skbuff.c:1256)
[  238.030032][  T318]  pfifo_fast_reset (./include/linux/ptr_ring.h:171 ./include/linux/ptr_ring.h:309 ./include/linux/skb_array.h:98 net/sched/sch_generic.c:827)
[  238.030039][  T318]  ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
...
[  238.030054][  T318]  qdisc_reset (net/sched/sch_generic.c:1034)
[  238.030062][  T318]  teql_destroy (./include/linux/spinlock.h:395 net/sched/sch_teql.c:157)
[  238.030071][  T318]  __qdisc_destroy (./include/net/pkt_sched.h:328 net/sched/sch_generic.c:1077)
[  238.030077][  T318]  qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159)
[  238.030089][  T318]  ? __pfx_qdisc_graft (net/sched/sch_api.c:1091)
[  238.030095][  T318]  ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[  238.030102][  T318]  ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[  238.030106][  T318]  ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221)
[  238.030114][  T318]  tc_get_qdisc (net/sched/sch_api.c:1529 net/sched/sch_api.c:1556)
...
[  238.072958][  T318] Allocated by task 303 on cpu 5 at 238.026275s:
[  238.073392][  T318]  kasan_save_stack (mm/kasan/common.c:58)
[  238.073884][  T318]  kasan_save_track (mm/kasan/common.c:64 (discriminator 5) mm/kasan/common.c:79 (discriminator 5))
[  238.074230][  T318]  __kasan_slab_alloc (mm/kasan/common.c:369)
[  238.074578][  T318]  kmem_cache_alloc_node_noprof (./include/linux/kasan.h:253 mm/slub.c:4542 mm/slub.c:4869 mm/slub.c:4921)
[  238.076091][  T318]  kmalloc_reserve (net/core/skbuff.c:616 (discriminator 107))
[  238.076450][  T318]  __alloc_skb (net/core/skbuff.c:713)
[  238.076834][  T318]  alloc_skb_with_frags (./include/linux/skbuff.h:1383 net/core/skbuff.c:6763)
[  238.077178][  T318]  sock_alloc_send_pskb (net/core/sock.c:2997)
[  238.077520][  T318]  packet_sendmsg (net/packet/af_packet.c:2926 net/packet/af_packet.c:3019 net/packet/af_packet.c:3108)
[  238.081469][  T318]
[  238.081870][  T318] Freed by task 299 on cpu 1 at 238.028496s:
[  238.082761][  T318]  kasan_save_stack (mm/kasan/common.c:58)
[  238.083481][  T318]  kasan_save_track (mm/kasan/common.c:64 (discriminator 5) mm/kasan/common.c:79 (discriminator 5))
[  238.085348][  T318]  kasan_save_free_info (mm/kasan/generic.c:587 (discriminator 1))
[  238.085900][  T318]  __kasan_slab_free (mm/kasan/common.c:287)
[  238.086439][  T318]  kmem_cache_free (mm/slub.c:6168 (discriminator 3) mm/slub.c:6298 (discriminator 3))
[  238.087007][  T318]  skb_release_data (net/core/skbuff.c:1139)
[  238.087491][  T318]  consume_skb (net/core/skbuff.c:1451)
[  238.087757][  T318]  teql_master_xmit (net/sched/sch_teql.c:358)
[  238.088116][  T318]  dev_hard_start_xmit (./include/linux/netdevice.h:5324 ./include/linux/netdevice.h:5333 net/core/dev.c:3871 net/core/dev.c:3887)
[  238.088468][  T318]  sch_direct_xmit (net/sched/sch_generic.c:347)
[  238.088820][  T318]  __qdisc_run (net/sched/sch_generic.c:420 (discriminator 1))
[  238.089166][  T318]  __dev_queue_xmit (./include/net/sch_generic.h:229 ./include/net/pkt_sched.h:121 ./include/net/pkt_sched.h:117 net/core/dev.c:4196 net/core/dev.c:4802)

Workflow to reproduce:
1. Initialize a TEQL topology (dummy0 and ifb0 as slaves, teql0 up).
2. Start multiple sender workers continuously transmitting packets
   through teql0 to drive teql_master_xmit().
3. In parallel, repeatedly delete and re-add the root qdisc on
   dummy0 and ifb0 via RTNETLINK, forcing frequent teardown and reset activity
   (teql_destroy() / qdisc_reset()).
4. After running both workloads concurrently for several iterations,
   KASAN reports slab-use-after-free or double-free in the skb free path.

Fix this by moving dev_reset_queue to sch_generic.h and calling it, instead
of qdisc_reset, in teql_destroy since it handles both the lock and lockless
cases correctly for root qdiscs.

Fixes: 96009c7d500e ("sched: replace __QDISC_STATE_RUNNING bit with a spin lock")
Reported-by: Xianrui Dong 
Tested-by: Xianrui Dong 
Co-developed-by: Victor Nogueira 
Signed-off-by: Victor Nogueira 
Signed-off-by: Jamal Hadi Salim 
Link: https://patch.msgid.link/20260315155422.147256-1-jhs@mojatatu.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

nf_tables: nft_dynset: fix possible stateful expression memleak in error path

2026-03-25T10:10:40+00:00

[ Upstream commit 0548a13b5a145b16e4da0628b5936baf35f51b43 ]

If cloning the second stateful expression in the element via GFP_ATOMIC
fails, then the first stateful expression remains in place without being
released.

   unreferenced object (percpu) 0x607b97e9cab8 (size 16):
     comm "softirq", pid 0, jiffies 4294931867
     hex dump (first 16 bytes on cpu 3):
       00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     backtrace (crc 0):
       pcpu_alloc_noprof+0x453/0xd80
       nft_counter_clone+0x9c/0x190 [nf_tables]
       nft_expr_clone+0x8f/0x1b0 [nf_tables]
       nft_dynset_new+0x2cb/0x5f0 [nf_tables]
       nft_rhash_update+0x236/0x11c0 [nf_tables]
       nft_dynset_eval+0x11f/0x670 [nf_tables]
       nft_do_chain+0x253/0x1700 [nf_tables]
       nft_do_chain_ipv4+0x18d/0x270 [nf_tables]
       nf_hook_slow+0xaa/0x1e0
       ip_local_deliver+0x209/0x330

Fixes: 563125a73ac3 ("netfilter: nftables: generalize set extension to support for several expressions")
Reported-by: Gurpreet Shergill 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Florian Westphal 
Signed-off-by: Sasha Levin

net: prevent NULL deref in ip[6]tunnel_xmit()

2026-03-19T15:08:21+00:00

[ Upstream commit c38b8f5f791ecce13ab77e2257f8fd2444ba80f6 ]

Blamed commit missed that both functions can be called with dev == NULL.

Also add unlikely() hints for these conditions that only fuzzers can hit.

Fixes: 6f1a9140ecda ("net: add xmit recursion limit to tunnel xmit functions")
Signed-off-by: Eric Dumazet 
CC: Weiming Shi 
Link: https://patch.msgid.link/20260312043908.2790803-1-edumazet@google.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin