| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Validate UAC3 cluster segment descriptors
UAC3 class segment descriptors need to be verified whether their sizes
match with the declared lengths and whether they fit with the
allocated buffer sizes, too. Otherwise malicious firmware may lead to
the unexpected OOB accesses. |
| In the Linux kernel, the following vulnerability has been resolved:
cnic: Fix use-after-free bugs in cnic_delete_task
The original code uses cancel_delayed_work() in cnic_cm_stop_bnx2x_hw(),
which does not guarantee that the delayed work item 'delete_task' has
fully completed if it was already running. Additionally, the delayed work
item is cyclic, the flush_workqueue() in cnic_cm_stop_bnx2x_hw() only
blocks and waits for work items that were already queued to the
workqueue prior to its invocation. Any work items submitted after
flush_workqueue() is called are not included in the set of tasks that the
flush operation awaits. This means that after the cyclic work items have
finished executing, a delayed work item may still exist in the workqueue.
This leads to use-after-free scenarios where the cnic_dev is deallocated
by cnic_free_dev(), while delete_task remains active and attempt to
dereference cnic_dev in cnic_delete_task().
A typical race condition is illustrated below:
CPU 0 (cleanup) | CPU 1 (delayed work callback)
cnic_netdev_event() |
cnic_stop_hw() | cnic_delete_task()
cnic_cm_stop_bnx2x_hw() | ...
cancel_delayed_work() | /* the queue_delayed_work()
flush_workqueue() | executes after flush_workqueue()*/
| queue_delayed_work()
cnic_free_dev(dev)//free | cnic_delete_task() //new instance
| dev = cp->dev; //use
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the cyclic delayed work item is properly canceled and that any
ongoing execution of the work item completes before the cnic_dev is
deallocated. Furthermore, since cancel_delayed_work_sync() uses
__flush_work(work, true) to synchronously wait for any currently
executing instance of the work item to finish, the flush_workqueue()
becomes redundant and should be removed.
This bug was identified through static analysis. To reproduce the issue
and validate the fix, I simulated the cnic PCI device in QEMU and
introduced intentional delays — such as inserting calls to ssleep()
within the cnic_delete_task() function — to increase the likelihood
of triggering the bug. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: algif_hash - fix double free in hash_accept
If accept(2) is called on socket type algif_hash with
MSG_MORE flag set and crypto_ahash_import fails,
sk2 is freed. However, it is also freed in af_alg_release,
leading to slab-use-after-free error. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject narrower access to pointer ctx fields
The following BPF program, simplified from a syzkaller repro, causes a
kernel warning:
r0 = *(u8 *)(r1 + 169);
exit;
With pointer field sk being at offset 168 in __sk_buff. This access is
detected as a narrower read in bpf_skb_is_valid_access because it
doesn't match offsetof(struct __sk_buff, sk). It is therefore allowed
and later proceeds to bpf_convert_ctx_access. Note that for the
"is_narrower_load" case in the convert_ctx_accesses(), the insn->off
is aligned, so the cnt may not be 0 because it matches the
offsetof(struct __sk_buff, sk) in the bpf_convert_ctx_access. However,
the target_size stays 0 and the verifier errors with a kernel warning:
verifier bug: error during ctx access conversion(1)
This patch fixes that to return a proper "invalid bpf_context access
off=X size=Y" error on the load instruction.
The same issue affects multiple other fields in context structures that
allow narrow access. Some other non-affected fields (for sk_msg,
sk_lookup, and sockopt) were also changed to use bpf_ctx_range_ptr for
consistency.
Note this syzkaller crash was reported in the "Closes" link below, which
used to be about a different bug, fixed in
commit fce7bd8e385a ("bpf/verifier: Handle BPF_LOAD_ACQ instructions
in insn_def_regno()"). Because syzbot somehow confused the two bugs,
the new crash and repro didn't get reported to the mailing list. |
| In the Linux kernel, the following vulnerability has been resolved:
vsock/virtio: fix potential underflow in virtio_transport_get_credit()
The credit calculation in virtio_transport_get_credit() uses unsigned
arithmetic:
ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
If the peer shrinks its advertised buffer (peer_buf_alloc) while bytes
are in flight, the subtraction can underflow and produce a large
positive value, potentially allowing more data to be queued than the
peer can handle.
Reuse virtio_transport_has_space() which already handles this case and
add a comment to make it clear why we are doing that.
[Stefano: use virtio_transport_has_space() instead of duplicating the code]
[Stefano: tweak the commit message] |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/iwcm: Fix use-after-free of work objects after cm_id destruction
The commit 59c68ac31e15 ("iw_cm: free cm_id resources on the last
deref") simplified cm_id resource management by freeing cm_id once all
references to the cm_id were removed. The references are removed either
upon completion of iw_cm event handlers or when the application destroys
the cm_id. This commit introduced the use-after-free condition where
cm_id_private object could still be in use by event handler works during
the destruction of cm_id. The commit aee2424246f9 ("RDMA/iwcm: Fix a
use-after-free related to destroying CM IDs") addressed this use-after-
free by flushing all pending works at the cm_id destruction.
However, still another use-after-free possibility remained. It happens
with the work objects allocated for each cm_id_priv within
alloc_work_entries() during cm_id creation, and subsequently freed in
dealloc_work_entries() once all references to the cm_id are removed.
If the cm_id's last reference is decremented in the event handler work,
the work object for the work itself gets removed, and causes the use-
after-free BUG below:
BUG: KASAN: slab-use-after-free in __pwq_activate_work+0x1ff/0x250
Read of size 8 at addr ffff88811f9cf800 by task kworker/u16:1/147091
CPU: 2 UID: 0 PID: 147091 Comm: kworker/u16:1 Not tainted 6.15.0-rc2+ #27 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
Workqueue: 0x0 (iw_cm_wq)
Call Trace:
<TASK>
dump_stack_lvl+0x6a/0x90
print_report+0x174/0x554
? __virt_addr_valid+0x208/0x430
? __pwq_activate_work+0x1ff/0x250
kasan_report+0xae/0x170
? __pwq_activate_work+0x1ff/0x250
__pwq_activate_work+0x1ff/0x250
pwq_dec_nr_in_flight+0x8c5/0xfb0
process_one_work+0xc11/0x1460
? __pfx_process_one_work+0x10/0x10
? assign_work+0x16c/0x240
worker_thread+0x5ef/0xfd0
? __pfx_worker_thread+0x10/0x10
kthread+0x3b0/0x770
? __pfx_kthread+0x10/0x10
? rcu_is_watching+0x11/0xb0
? _raw_spin_unlock_irq+0x24/0x50
? rcu_is_watching+0x11/0xb0
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x70
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 147416:
kasan_save_stack+0x2c/0x50
kasan_save_track+0x10/0x30
__kasan_kmalloc+0xa6/0xb0
alloc_work_entries+0xa9/0x260 [iw_cm]
iw_cm_connect+0x23/0x4a0 [iw_cm]
rdma_connect_locked+0xbfd/0x1920 [rdma_cm]
nvme_rdma_cm_handler+0x8e5/0x1b60 [nvme_rdma]
cma_cm_event_handler+0xae/0x320 [rdma_cm]
cma_work_handler+0x106/0x1b0 [rdma_cm]
process_one_work+0x84f/0x1460
worker_thread+0x5ef/0xfd0
kthread+0x3b0/0x770
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30
Freed by task 147091:
kasan_save_stack+0x2c/0x50
kasan_save_track+0x10/0x30
kasan_save_free_info+0x37/0x60
__kasan_slab_free+0x4b/0x70
kfree+0x13a/0x4b0
dealloc_work_entries+0x125/0x1f0 [iw_cm]
iwcm_deref_id+0x6f/0xa0 [iw_cm]
cm_work_handler+0x136/0x1ba0 [iw_cm]
process_one_work+0x84f/0x1460
worker_thread+0x5ef/0xfd0
kthread+0x3b0/0x770
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30
Last potentially related work creation:
kasan_save_stack+0x2c/0x50
kasan_record_aux_stack+0xa3/0xb0
__queue_work+0x2ff/0x1390
queue_work_on+0x67/0xc0
cm_event_handler+0x46a/0x820 [iw_cm]
siw_cm_upcall+0x330/0x650 [siw]
siw_cm_work_handler+0x6b9/0x2b20 [siw]
process_one_work+0x84f/0x1460
worker_thread+0x5ef/0xfd0
kthread+0x3b0/0x770
ret_from_fork+0x30/0x70
ret_from_fork_asm+0x1a/0x30
This BUG is reproducible by repeating the blktests test case nvme/061
for the rdma transport and the siw driver.
To avoid the use-after-free of cm_id_private work objects, ensure that
the last reference to the cm_id is decremented not in the event handler
works, but in the cm_id destruction context. For that purpose, mo
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ath10k: fix dma_free_coherent() pointer
dma_alloc_coherent() allocates a DMA mapped buffer and stores the
addresses in XXX_unaligned fields. Those should be reused when freeing
the buffer rather than the aligned addresses. |
| In the Linux kernel, the following vulnerability has been resolved:
md: suspend array while updating raid_disks via sysfs
In raid1_reshape(), freeze_array() is called before modifying the r1bio
memory pool (conf->r1bio_pool) and conf->raid_disks, and
unfreeze_array() is called after the update is completed.
However, freeze_array() only waits until nr_sync_pending and
(nr_pending - nr_queued) of all buckets reaches zero. When an I/O error
occurs, nr_queued is increased and the corresponding r1bio is queued to
either retry_list or bio_end_io_list. As a result, freeze_array() may
unblock before these r1bios are released.
This can lead to a situation where conf->raid_disks and the mempool have
already been updated while queued r1bios, allocated with the old
raid_disks value, are later released. Consequently, free_r1bio() may
access memory out of bounds in put_all_bios() and release r1bios of the
wrong size to the new mempool, potentially causing issues with the
mempool as well.
Since only normal I/O might increase nr_queued while an I/O error occurs,
suspending the array avoids this issue.
Note: Updating raid_disks via ioctl SET_ARRAY_INFO already suspends
the array. Therefore, we suspend the array when updating raid_disks
via sysfs to avoid this issue too. |
| In the Linux kernel, the following vulnerability has been resolved:
via_wdt: fix critical boot hang due to unnamed resource allocation
The VIA watchdog driver uses allocate_resource() to reserve a MMIO
region for the watchdog control register. However, the allocated
resource was not given a name, which causes the kernel resource tree
to contain an entry marked as "<BAD>" under /proc/iomem on x86
platforms.
During boot, this unnamed resource can lead to a critical hang because
subsequent resource lookups and conflict checks fail to handle the
invalid entry properly. |
| In the Linux kernel, the following vulnerability has been resolved:
devlink: rate: Unset parent pointer in devl_rate_nodes_destroy
The function devl_rate_nodes_destroy is documented to "Unset parent for
all rate objects". However, it was only calling the driver-specific
`rate_leaf_parent_set` or `rate_node_parent_set` ops and decrementing
the parent's refcount, without actually setting the
`devlink_rate->parent` pointer to NULL.
This leaves a dangling pointer in the `devlink_rate` struct, which cause
refcount error in netdevsim[1] and mlx5[2]. In addition, this is
inconsistent with the behavior of `devlink_nl_rate_parent_node_set`,
where the parent pointer is correctly cleared.
This patch fixes the issue by explicitly setting `devlink_rate->parent`
to NULL after notifying the driver, thus fulfilling the function's
documented behavior for all rate objects.
[1]
repro steps:
echo 1 > /sys/bus/netdevsim/new_device
devlink dev eswitch set netdevsim/netdevsim1 mode switchdev
echo 1 > /sys/bus/netdevsim/devices/netdevsim1/sriov_numvfs
devlink port function rate add netdevsim/netdevsim1/test_node
devlink port function rate set netdevsim/netdevsim1/128 parent test_node
echo 1 > /sys/bus/netdevsim/del_device
dmesg:
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 8 PID: 1530 at lib/refcount.c:31 refcount_warn_saturate+0x42/0xe0
CPU: 8 UID: 0 PID: 1530 Comm: bash Not tainted 6.18.0-rc4+ #1 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0x42/0xe0
Call Trace:
<TASK>
devl_rate_leaf_destroy+0x8d/0x90
__nsim_dev_port_del+0x6c/0x70 [netdevsim]
nsim_dev_reload_destroy+0x11c/0x140 [netdevsim]
nsim_drv_remove+0x2b/0xb0 [netdevsim]
device_release_driver_internal+0x194/0x1f0
bus_remove_device+0xc6/0x130
device_del+0x159/0x3c0
device_unregister+0x1a/0x60
del_device_store+0x111/0x170 [netdevsim]
kernfs_fop_write_iter+0x12e/0x1e0
vfs_write+0x215/0x3d0
ksys_write+0x5f/0xd0
do_syscall_64+0x55/0x10f0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
[2]
devlink dev eswitch set pci/0000:08:00.0 mode switchdev
devlink port add pci/0000:08:00.0 flavour pcisf pfnum 0 sfnum 1000
devlink port function rate add pci/0000:08:00.0/group1
devlink port function rate set pci/0000:08:00.0/32768 parent group1
modprobe -r mlx5_ib mlx5_fwctl mlx5_core
dmesg:
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 7 PID: 16151 at lib/refcount.c:31 refcount_warn_saturate+0x42/0xe0
CPU: 7 UID: 0 PID: 16151 Comm: bash Not tainted 6.17.0-rc7_for_upstream_min_debug_2025_10_02_12_44 #1 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0x42/0xe0
Call Trace:
<TASK>
devl_rate_leaf_destroy+0x8d/0x90
mlx5_esw_offloads_devlink_port_unregister+0x33/0x60 [mlx5_core]
mlx5_esw_offloads_unload_rep+0x3f/0x50 [mlx5_core]
mlx5_eswitch_unload_sf_vport+0x40/0x90 [mlx5_core]
mlx5_sf_esw_event+0xc4/0x120 [mlx5_core]
notifier_call_chain+0x33/0xa0
blocking_notifier_call_chain+0x3b/0x50
mlx5_eswitch_disable_locked+0x50/0x110 [mlx5_core]
mlx5_eswitch_disable+0x63/0x90 [mlx5_core]
mlx5_unload+0x1d/0x170 [mlx5_core]
mlx5_uninit_one+0xa2/0x130 [mlx5_core]
remove_one+0x78/0xd0 [mlx5_core]
pci_device_remove+0x39/0xa0
device_release_driver_internal+0x194/0x1f0
unbind_store+0x99/0xa0
kernfs_fop_write_iter+0x12e/0x1e0
vfs_write+0x215/0x3d0
ksys_write+0x5f/0xd0
do_syscall_64+0x53/0x1f0
entry_SYSCALL_64_after_hwframe+0x4b/0x53 |
| In the Linux kernel, the following vulnerability has been resolved:
ip6_gre: make ip6gre_header() robust
Over the years, syzbot found many ways to crash the kernel
in ip6gre_header() [1].
This involves team or bonding drivers ability to dynamically
change their dev->needed_headroom and/or dev->hard_header_len
In this particular crash mld_newpack() allocated an skb
with a too small reserve/headroom, and by the time mld_sendpack()
was called, syzbot managed to attach an ip6gre device.
[1]
skbuff: skb_under_panic: text:ffffffff8a1d69a8 len:136 put:40 head:ffff888059bc7000 data:ffff888059bc6fe8 tail:0x70 end:0x6c0 dev:team0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:213 !
<TASK>
skb_under_panic net/core/skbuff.c:223 [inline]
skb_push+0xc3/0xe0 net/core/skbuff.c:2641
ip6gre_header+0xc8/0x790 net/ipv6/ip6_gre.c:1371
dev_hard_header include/linux/netdevice.h:3436 [inline]
neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618
neigh_output include/net/neighbour.h:556 [inline]
ip6_finish_output2+0xfb3/0x1480 net/ipv6/ip6_output.c:136
__ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:220
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
mld_send_cr net/ipv6/mcast.c:2154 [inline]
mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693 |
| In the Linux kernel, the following vulnerability has been resolved:
spi: tegra210-quad: Protect curr_xfer in tegra_qspi_combined_seq_xfer
The curr_xfer field is read by the IRQ handler without holding the lock
to check if a transfer is in progress. When clearing curr_xfer in the
combined sequence transfer loop, protect it with the spinlock to prevent
a race with the interrupt handler.
Protect the curr_xfer clearing at the exit path of
tegra_qspi_combined_seq_xfer() with the spinlock to prevent a race
with the interrupt handler that reads this field.
Without this protection, the IRQ handler could read a partially updated
curr_xfer value, leading to NULL pointer dereference or use-after-free. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_event: call disconnect callback before deleting conn
In hci_cs_disconnect, we do hci_conn_del even if disconnection failed.
ISO, L2CAP and SCO connections refer to the hci_conn without
hci_conn_get, so disconn_cfm must be called so they can clean up their
conn, otherwise use-after-free occurs.
ISO:
==========================================================
iso_sock_connect:880: sk 00000000eabd6557
iso_connect_cis:356: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7e:da
...
iso_conn_add:140: hcon 000000001696f1fd conn 00000000b6251073
hci_dev_put:1487: hci0 orig refcnt 17
__iso_chan_add:214: conn 00000000b6251073
iso_sock_clear_timer:117: sock 00000000eabd6557 state 3
...
hci_rx_work:4085: hci0 Event packet
hci_event_packet:7601: hci0: event 0x0f
hci_cmd_status_evt:4346: hci0: opcode 0x0406
hci_cs_disconnect:2760: hci0: status 0x0c
hci_sent_cmd_data:3107: hci0 opcode 0x0406
hci_conn_del:1151: hci0 hcon 000000001696f1fd handle 2560
hci_conn_unlink:1102: hci0: hcon 000000001696f1fd
hci_conn_drop:1451: hcon 00000000d8521aaf orig refcnt 2
hci_chan_list_flush:2780: hcon 000000001696f1fd
hci_dev_put:1487: hci0 orig refcnt 21
hci_dev_put:1487: hci0 orig refcnt 20
hci_req_cmd_complete:3978: opcode 0x0406 status 0x0c
... <no iso_* activity on sk/conn> ...
iso_sock_sendmsg:1098: sock 00000000dea5e2e0, sk 00000000eabd6557
BUG: kernel NULL pointer dereference, address: 0000000000000668
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
RIP: 0010:iso_sock_sendmsg (net/bluetooth/iso.c:1112) bluetooth
==========================================================
L2CAP:
==================================================================
hci_cmd_status_evt:4359: hci0: opcode 0x0406
hci_cs_disconnect:2760: hci0: status 0x0c
hci_sent_cmd_data:3085: hci0 opcode 0x0406
hci_conn_del:1151: hci0 hcon ffff88800c999000 handle 3585
hci_conn_unlink:1102: hci0: hcon ffff88800c999000
hci_chan_list_flush:2780: hcon ffff88800c999000
hci_chan_del:2761: hci0 hcon ffff88800c999000 chan ffff888018ddd280
...
BUG: KASAN: slab-use-after-free in hci_send_acl+0x2d/0x540 [bluetooth]
Read of size 8 at addr ffff888018ddd298 by task bluetoothd/1175
CPU: 0 PID: 1175 Comm: bluetoothd Tainted: G E 6.4.0-rc4+ #2
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x5b/0x90
print_report+0xcf/0x670
? __virt_addr_valid+0xf8/0x180
? hci_send_acl+0x2d/0x540 [bluetooth]
kasan_report+0xa8/0xe0
? hci_send_acl+0x2d/0x540 [bluetooth]
hci_send_acl+0x2d/0x540 [bluetooth]
? __pfx___lock_acquire+0x10/0x10
l2cap_chan_send+0x1fd/0x1300 [bluetooth]
? l2cap_sock_sendmsg+0xf2/0x170 [bluetooth]
? __pfx_l2cap_chan_send+0x10/0x10 [bluetooth]
? lock_release+0x1d5/0x3c0
? mark_held_locks+0x1a/0x90
l2cap_sock_sendmsg+0x100/0x170 [bluetooth]
sock_write_iter+0x275/0x280
? __pfx_sock_write_iter+0x10/0x10
? __pfx___lock_acquire+0x10/0x10
do_iter_readv_writev+0x176/0x220
? __pfx_do_iter_readv_writev+0x10/0x10
? find_held_lock+0x83/0xa0
? selinux_file_permission+0x13e/0x210
do_iter_write+0xda/0x340
vfs_writev+0x1b4/0x400
? __pfx_vfs_writev+0x10/0x10
? __seccomp_filter+0x112/0x750
? populate_seccomp_data+0x182/0x220
? __fget_light+0xdf/0x100
? do_writev+0x19d/0x210
do_writev+0x19d/0x210
? __pfx_do_writev+0x10/0x10
? mark_held_locks+0x1a/0x90
do_syscall_64+0x60/0x90
? lockdep_hardirqs_on_prepare+0x149/0x210
? do_syscall_64+0x6c/0x90
? lockdep_hardirqs_on_prepare+0x149/0x210
entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7ff45cb23e64
Code: 15 d1 1f 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 80 3d 9d a7 0d 00 00 74 13 b8 14 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 89 54 24 1c 48 89
RSP: 002b:00007fff21ae09b8 EFLAGS: 00000202 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX:
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
bridge: mcast: Fix use-after-free during router port configuration
The bridge maintains a global list of ports behind which a multicast
router resides. The list is consulted during forwarding to ensure
multicast packets are forwarded to these ports even if the ports are not
member in the matching MDB entry.
When per-VLAN multicast snooping is enabled, the per-port multicast
context is disabled on each port and the port is removed from the global
router port list:
# ip link add name br1 up type bridge vlan_filtering 1 mcast_snooping 1
# ip link add name dummy1 up master br1 type dummy
# ip link set dev dummy1 type bridge_slave mcast_router 2
$ bridge -d mdb show | grep router
router ports on br1: dummy1
# ip link set dev br1 type bridge mcast_vlan_snooping 1
$ bridge -d mdb show | grep router
However, the port can be re-added to the global list even when per-VLAN
multicast snooping is enabled:
# ip link set dev dummy1 type bridge_slave mcast_router 0
# ip link set dev dummy1 type bridge_slave mcast_router 2
$ bridge -d mdb show | grep router
router ports on br1: dummy1
Since commit 4b30ae9adb04 ("net: bridge: mcast: re-implement
br_multicast_{enable, disable}_port functions"), when per-VLAN multicast
snooping is enabled, multicast disablement on a port will disable the
per-{port, VLAN} multicast contexts and not the per-port one. As a
result, a port will remain in the global router port list even after it
is deleted. This will lead to a use-after-free [1] when the list is
traversed (when adding a new port to the list, for example):
# ip link del dev dummy1
# ip link add name dummy2 up master br1 type dummy
# ip link set dev dummy2 type bridge_slave mcast_router 2
Similarly, stale entries can also be found in the per-VLAN router port
list. When per-VLAN multicast snooping is disabled, the per-{port, VLAN}
contexts are disabled on each port and the port is removed from the
per-VLAN router port list:
# ip link add name br1 up type bridge vlan_filtering 1 mcast_snooping 1 mcast_vlan_snooping 1
# ip link add name dummy1 up master br1 type dummy
# bridge vlan add vid 2 dev dummy1
# bridge vlan global set vid 2 dev br1 mcast_snooping 1
# bridge vlan set vid 2 dev dummy1 mcast_router 2
$ bridge vlan global show dev br1 vid 2 | grep router
router ports: dummy1
# ip link set dev br1 type bridge mcast_vlan_snooping 0
$ bridge vlan global show dev br1 vid 2 | grep router
However, the port can be re-added to the per-VLAN list even when
per-VLAN multicast snooping is disabled:
# bridge vlan set vid 2 dev dummy1 mcast_router 0
# bridge vlan set vid 2 dev dummy1 mcast_router 2
$ bridge vlan global show dev br1 vid 2 | grep router
router ports: dummy1
When the VLAN is deleted from the port, the per-{port, VLAN} multicast
context will not be disabled since multicast snooping is not enabled
on the VLAN. As a result, the port will remain in the per-VLAN router
port list even after it is no longer member in the VLAN. This will lead
to a use-after-free [2] when the list is traversed (when adding a new
port to the list, for example):
# ip link add name dummy2 up master br1 type dummy
# bridge vlan add vid 2 dev dummy2
# bridge vlan del vid 2 dev dummy1
# bridge vlan set vid 2 dev dummy2 mcast_router 2
Fix these issues by removing the port from the relevant (global or
per-VLAN) router port list in br_multicast_port_ctx_deinit(). The
function is invoked during port deletion with the per-port multicast
context and during VLAN deletion with the per-{port, VLAN} multicast
context.
Note that deleting the multicast router timer is not enough as it only
takes care of the temporary multicast router states (1 or 3) and not the
permanent one (2).
[1]
BUG: KASAN: slab-out-of-bounds in br_multicast_add_router.part.0+0x3f1/0x560
Write of size 8 at addr ffff888004a67328 by task ip/384
[...]
Call Trace:
<TASK>
dump_stack
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: fix off-by-one error in do_split
Syzkaller detected a use-after-free issue in ext4_insert_dentry that was
caused by out-of-bounds access due to incorrect splitting in do_split.
BUG: KASAN: use-after-free in ext4_insert_dentry+0x36a/0x6d0 fs/ext4/namei.c:2109
Write of size 251 at addr ffff888074572f14 by task syz-executor335/5847
CPU: 0 UID: 0 PID: 5847 Comm: syz-executor335 Not tainted 6.12.0-rc6-syzkaller-00318-ga9cda7c0ffed #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
__asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106
ext4_insert_dentry+0x36a/0x6d0 fs/ext4/namei.c:2109
add_dirent_to_buf+0x3d9/0x750 fs/ext4/namei.c:2154
make_indexed_dir+0xf98/0x1600 fs/ext4/namei.c:2351
ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2455
ext4_add_nondir+0x8d/0x290 fs/ext4/namei.c:2796
ext4_symlink+0x920/0xb50 fs/ext4/namei.c:3431
vfs_symlink+0x137/0x2e0 fs/namei.c:4615
do_symlinkat+0x222/0x3a0 fs/namei.c:4641
__do_sys_symlink fs/namei.c:4662 [inline]
__se_sys_symlink fs/namei.c:4660 [inline]
__x64_sys_symlink+0x7a/0x90 fs/namei.c:4660
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
The following loop is located right above 'if' statement.
for (i = count-1; i >= 0; i--) {
/* is more than half of this entry in 2nd half of the block? */
if (size + map[i].size/2 > blocksize/2)
break;
size += map[i].size;
move++;
}
'i' in this case could go down to -1, in which case sum of active entries
wouldn't exceed half the block size, but previous behaviour would also do
split in half if sum would exceed at the very last block, which in case of
having too many long name files in a single block could lead to
out-of-bounds access and following use-after-free.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller. |
| In the Linux kernel, the following vulnerability has been resolved:
eventpoll: don't decrement ep refcount while still holding the ep mutex
Jann Horn points out that epoll is decrementing the ep refcount and then
doing a
mutex_unlock(&ep->mtx);
afterwards. That's very wrong, because it can lead to a use-after-free.
That pattern is actually fine for the very last reference, because the
code in question will delay the actual call to "ep_free(ep)" until after
it has unlocked the mutex.
But it's wrong for the much subtler "next to last" case when somebody
*else* may also be dropping their reference and free the ep while we're
still using the mutex.
Note that this is true even if that other user is also using the same ep
mutex: mutexes, unlike spinlocks, can not be used for object ownership,
even if they guarantee mutual exclusion.
A mutex "unlock" operation is not atomic, and as one user is still
accessing the mutex as part of unlocking it, another user can come in
and get the now released mutex and free the data structure while the
first user is still cleaning up.
See our mutex documentation in Documentation/locking/mutex-design.rst,
in particular the section [1] about semantics:
"mutex_unlock() may access the mutex structure even after it has
internally released the lock already - so it's not safe for
another context to acquire the mutex and assume that the
mutex_unlock() context is not using the structure anymore"
So if we drop our ep ref before the mutex unlock, but we weren't the
last one, we may then unlock the mutex, another user comes in, drops
_their_ reference and releases the 'ep' as it now has no users - all
while the mutex_unlock() is still accessing it.
Fix this by simply moving the ep refcount dropping to outside the mutex:
the refcount itself is atomic, and doesn't need mutex protection (that's
the whole _point_ of refcounts: unlike mutexes, they are inherently
about object lifetimes). |
| In the Linux kernel, the following vulnerability has been resolved:
sctp: move SCTP_CMD_ASSOC_SHKEY right after SCTP_CMD_PEER_INIT
A null-ptr-deref was reported in the SCTP transmit path when SCTP-AUTH key
initialization fails:
==================================================================
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 16 Comm: ksoftirqd/0 Tainted: G W 6.6.0 #2
RIP: 0010:sctp_packet_bundle_auth net/sctp/output.c:264 [inline]
RIP: 0010:sctp_packet_append_chunk+0xb36/0x1260 net/sctp/output.c:401
Call Trace:
sctp_packet_transmit_chunk+0x31/0x250 net/sctp/output.c:189
sctp_outq_flush_data+0xa29/0x26d0 net/sctp/outqueue.c:1111
sctp_outq_flush+0xc80/0x1240 net/sctp/outqueue.c:1217
sctp_cmd_interpreter.isra.0+0x19a5/0x62c0 net/sctp/sm_sideeffect.c:1787
sctp_side_effects net/sctp/sm_sideeffect.c:1198 [inline]
sctp_do_sm+0x1a3/0x670 net/sctp/sm_sideeffect.c:1169
sctp_assoc_bh_rcv+0x33e/0x640 net/sctp/associola.c:1052
sctp_inq_push+0x1dd/0x280 net/sctp/inqueue.c:88
sctp_rcv+0x11ae/0x3100 net/sctp/input.c:243
sctp6_rcv+0x3d/0x60 net/sctp/ipv6.c:1127
The issue is triggered when sctp_auth_asoc_init_active_key() fails in
sctp_sf_do_5_1C_ack() while processing an INIT_ACK. In this case, the
command sequence is currently:
- SCTP_CMD_PEER_INIT
- SCTP_CMD_TIMER_STOP (T1_INIT)
- SCTP_CMD_TIMER_START (T1_COOKIE)
- SCTP_CMD_NEW_STATE (COOKIE_ECHOED)
- SCTP_CMD_ASSOC_SHKEY
- SCTP_CMD_GEN_COOKIE_ECHO
If SCTP_CMD_ASSOC_SHKEY fails, asoc->shkey remains NULL, while
asoc->peer.auth_capable and asoc->peer.peer_chunks have already been set by
SCTP_CMD_PEER_INIT. This allows a DATA chunk with auth = 1 and shkey = NULL
to be queued by sctp_datamsg_from_user().
Since command interpretation stops on failure, no COOKIE_ECHO should been
sent via SCTP_CMD_GEN_COOKIE_ECHO. However, the T1_COOKIE timer has already
been started, and it may enqueue a COOKIE_ECHO into the outqueue later. As
a result, the DATA chunk can be transmitted together with the COOKIE_ECHO
in sctp_outq_flush_data(), leading to the observed issue.
Similar to the other places where it calls sctp_auth_asoc_init_active_key()
right after sctp_process_init(), this patch moves the SCTP_CMD_ASSOC_SHKEY
immediately after SCTP_CMD_PEER_INIT, before stopping T1_INIT and starting
T1_COOKIE. This ensures that if shared key generation fails, authenticated
DATA cannot be sent. It also allows the T1_INIT timer to retransmit INIT,
giving the client another chance to process INIT_ACK and retry key setup. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: core: config: Prevent OOB read in SS endpoint companion parsing
usb_parse_ss_endpoint_companion() checks descriptor type before length,
enabling a potentially odd read outside of the buffer size.
Fix this up by checking the size first before looking at any of the
fields in the descriptor. |
| In the Linux kernel, the following vulnerability has been resolved:
leds: led-class: Only Add LED to leds_list when it is fully ready
Before this change the LED was added to leds_list before led_init_core()
gets called adding it the list before led_classdev.set_brightness_work gets
initialized.
This leaves a window where led_trigger_register() of a LED's default
trigger will call led_trigger_set() which calls led_set_brightness()
which in turn will end up queueing the *uninitialized*
led_classdev.set_brightness_work.
This race gets hit by the lenovo-thinkpad-t14s EC driver which registers
2 LEDs with a default trigger provided by snd_ctl_led.ko in quick
succession. The first led_classdev_register() causes an async modprobe of
snd_ctl_led to run and that async modprobe manages to exactly hit
the window where the second LED is on the leds_list without led_init_core()
being called for it, resulting in:
------------[ cut here ]------------
WARNING: CPU: 11 PID: 5608 at kernel/workqueue.c:4234 __flush_work+0x344/0x390
Hardware name: LENOVO 21N2S01F0B/21N2S01F0B, BIOS N42ET93W (2.23 ) 09/01/2025
...
Call trace:
__flush_work+0x344/0x390 (P)
flush_work+0x2c/0x50
led_trigger_set+0x1c8/0x340
led_trigger_register+0x17c/0x1c0
led_trigger_register_simple+0x84/0xe8
snd_ctl_led_init+0x40/0xf88 [snd_ctl_led]
do_one_initcall+0x5c/0x318
do_init_module+0x9c/0x2b8
load_module+0x7e0/0x998
Close the race window by moving the adding of the LED to leds_list to
after the led_init_core() call. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: Always pass notifications when child class becomes empty
Certain classful qdiscs may invoke their classes' dequeue handler on an
enqueue operation. This may unexpectedly empty the child qdisc and thus
make an in-flight class passive via qlen_notify(). Most qdiscs do not
expect such behaviour at this point in time and may re-activate the
class eventually anyways which will lead to a use-after-free.
The referenced fix commit attempted to fix this behavior for the HFSC
case by moving the backlog accounting around, though this turned out to
be incomplete since the parent's parent may run into the issue too.
The following reproducer demonstrates this use-after-free:
tc qdisc add dev lo root handle 1: drr
tc filter add dev lo parent 1: basic classid 1:1
tc class add dev lo parent 1: classid 1:1 drr
tc qdisc add dev lo parent 1:1 handle 2: hfsc def 1
tc class add dev lo parent 2: classid 2:1 hfsc rt m1 8 d 1 m2 0
tc qdisc add dev lo parent 2:1 handle 3: netem
tc qdisc add dev lo parent 3:1 handle 4: blackhole
echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888
tc class delete dev lo classid 1:1
echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888
Since backlog accounting issues leading to a use-after-frees on stale
class pointers is a recurring pattern at this point, this patch takes
a different approach. Instead of trying to fix the accounting, the patch
ensures that qdisc_tree_reduce_backlog always calls qlen_notify when
the child qdisc is empty. This solves the problem because deletion of
qdiscs always involves a call to qdisc_reset() and / or
qdisc_purge_queue() which ultimately resets its qlen to 0 thus causing
the following qdisc_tree_reduce_backlog() to report to the parent. Note
that this may call qlen_notify on passive classes multiple times. This
is not a problem after the recent patch series that made all the
classful qdiscs qlen_notify() handlers idempotent. |
