| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
posix-cpu-timers: Prevent UAF caused by non-leader exec() race
Wongi and Jungwoo decoded and reported a non-leader exec() related race
which can result in an UAF:
sys_timer_delete() exec()
posix_cpu_timer_del()
// Observes old leader
p = pid_task(pid, pid_type); de_thread()
switch_leader();
release_task(old_leader)
__exit_signal(old_leader)
sighand = lock(old_leader, sighand);
posix_cpu_timers*_exit();
sighand = lock_task_sighand(p) unhash_task(old_leader);
sh = lock(p, sighand) old_leader->sighand = NULL;
unlock(sighand);
(p->sighand == NULL)
unlock(sh)
return NULL;
// Returns without action
if(!sighand)
return 0;
free_posix_timer();
This is "harmless" unless the deleted timer was armed and enqueued in
p->signal because on exec() a TGID targeted timer is inherited.
As sys_timer_delete() freed the underlying posix timer object
run_posix_cpu_timers() or any timerqueue related add/delete operations on
other timers will access the freed object's timerqueue node, which results
in an UAF.
There is a similar problem vs. posix_cpu_timer_set(). For regular posix
timers it just transiently returns -ESRCH to user space, but for the use
case in do_cpu_nanosleep() it's the same UAF just that the k_itimer is
allocated on the stack.
Also posix_cpu_timer_rearm() fails to rearm the timer, which means it stops
to expire.
While debating solutions Frederic pointed out another problem:
posix_cpu_timer_del(tmr)
__exit_signal(p)
posix_cpu_timers*_exit(p);
unhash_task(p);
p->sighand = NULL;
sh = lock_task_sighand(p)
sighand = p->sighand;
if (!sighand)
return NULL;
lock(sighand);
if (!sh)
WARN_ON_ONCE(timer_queued(tmr));
On weakly ordered architectures it is not guaranteed that
posix_cpu_timer_del() will observe the stores in posix_cpu_timers*_exit()
when p->sighand is observed as NULL, which means the WARN() can be a false
positive.
Solve these issues by:
1) Changing the store in __exit_signal() to smp_store_release().
2) Adding a smp_acquire__after_ctrl_dep() into the !sighand path
of lock_task_sighand().
3) Creating a helper function for looking up the task and locking sighand
which does not return when sighand == NULL. Instead it retries the
task lookup and only if that fails it gives up.
4) Using that helper in the three affected functions.
#1/#2 ensures that the reader side which observes sighand == NULL also
observes all preceeding stores, i.e. the stores in posix_cpu_timers*_exit()
and the ones in unhash_task().
#3 ensures that the above described non-leader exec() situation is handled
gracefully. When the task lookup returns the old leader, but sighand ==
NULL then it retries. In the non-leader exec() case the subsequent task
lookup will observe the new leader due to #1/#2. In normal exit() scenarios
the subsequent lookup fails.
When the task lookup fails, the function also checks whether the timer is
still enqueued and issues a warning if that's the case. Unfortunately there
is nothing which can be done about it, but as the task is already not
longer visible the timer should not be accessed anymore. This check also
requires memory ordering, which is not provided when the first lookup
fails. To achieve that the check is preceeded by a smp_rmb() which pairs
with the smp_wmb() in write_seqlock() in __exit_signal(). That ensures that
the stores in posix_cpu_timers*_exit() are visible.
The history of the non-leader exec() issue goes back to the early days of
posix CPU timers, which stored a pointer to the group leader task in the
timer. That obviously fails when a non-leader exec() switches the leader.
commit e0a70217107e ("posix-cpu-timers: workaround to suppress the problems
with mt exec") added a temporary workaround for that in 2010 which surv
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: igmp: remove multicast group from hash table on device destruction
When a device is destroyed under RTNL, ip_mc_destroy_dev() iterates through
the multicast list and calls ip_ma_put() on each membership, scheduling
them for RCU reclamation. However, they are not unlinked from the device's
multicast hash table (mc_hash).
Since the device remains published in dev->ip_ptr until after
ip_mc_destroy_dev() completes, concurrent RCU readers traversing mc_hash
can still locate and access the multicast group after its refcount is
decremented. If the RCU callback runs and frees the group while a reader is
accessing it, a use-after-free occurs.
Fix this by unlinking the multicast group from mc_hash using
ip_mc_hash_remove() before scheduling it for reclamation.
BUG: KASAN: slab-use-after-free in ip_check_mc_rcu+0x149/0x3f0
Read of size 4 at addr ffff888009bf1408 by task mausezahn/2276
Call Trace:
<IRQ>
dump_stack_lvl+0x67/0x90
print_report+0x175/0x7c0
kasan_report+0x147/0x180
ip_check_mc_rcu+0x149/0x3f0
udp_v4_early_demux+0x36d/0x12d0
ip_rcv_finish_core+0xb8b/0x1390
ip_rcv_finish+0x54/0x120
NF_HOOK+0x213/0x2b0
__netif_receive_skb+0x126/0x340
process_backlog+0x4f2/0xf00
__napi_poll+0x92/0x2c0
net_rx_action+0x583/0xc60
handle_softirqs+0x236/0x7f0
do_softirq+0x57/0x80
</IRQ>
Allocated by task 2239:
kasan_save_track+0x3e/0x80
__kasan_kmalloc+0x72/0x90
____ip_mc_inc_group+0x31a/0xa40
__ip_mc_join_group+0x334/0x3f0
do_ip_setsockopt+0x16fa/0x2010
ip_setsockopt+0x3f/0x90
do_sock_setsockopt+0x1ad/0x300
Freed by task 0:
kasan_save_track+0x3e/0x80
kasan_save_free_info+0x40/0x50
__kasan_slab_free+0x3a/0x60
__rcu_free_sheaf_prepare+0xd4/0x220
rcu_free_sheaf+0x36/0x190
rcu_core+0x8d9/0x12f0
handle_softirqs+0x236/0x7f0 |
| In the Linux kernel, the following vulnerability has been resolved:
xfrm: policy: fix use-after-free on inexact bin in xfrm_policy_bysel_ctx()
Fix the race by pruning the bin while still holding xfrm_policy_lock,
before dropping it. Use __xfrm_policy_inexact_prune_bin() directly since
the lock is already held. The wrapper xfrm_policy_inexact_prune_bin()
becomes unused and is removed.
Race:
CPU0 (XFRM_MSG_DELPOLICY) CPU1 (XFRM_MSG_NEWSPDINFO)
========================== ==========================
xfrm_policy_bysel_ctx():
spin_lock_bh(xfrm_policy_lock)
bin = xfrm_policy_inexact_lookup()
__xfrm_policy_unlink(pol)
spin_unlock_bh(xfrm_policy_lock)
xfrm_policy_kill(ret)
// wide window, lock not held
xfrm_hash_rebuild():
spin_lock_bh(xfrm_policy_lock)
__xfrm_policy_inexact_flush():
kfree_rcu(bin) // bin freed
spin_unlock_bh(xfrm_policy_lock)
xfrm_policy_inexact_prune_bin(bin)
// UAF: bin is freed |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Free reuseport cBPF prog after RCU grace period.
Eulgyu Kim reported the splat below with a repro. [0]
The repro sets up a UDP reuseport group with a cBPF prog and
replaces it with a new one while another thread is sending
a UDP packet to the group.
The reuseport prog is freed by sk_reuseport_prog_free().
bpf_prog_put() is called for "e"BPF prog to destruct through
multiple stages while cBPF prog is freed immediately by
bpf_release_orig_filter() and bpf_prog_free().
If a reuseport prog is detached from the setsockopt() path
(reuseport_attach_prog() or reuseport_detach_prog()),
sk_reuseport_prog_free() is called without waiting for RCU
readers to complete, resulting in various bugs.
Let's defer freeing the reuseport cBPF prog after one RCU
grace period.
Note "e"BPF prog is safe as is unless the fast path starts
to touch fields destroyed in bpf_prog_put_deferred() and
__bpf_prog_put_noref().
[0]:
BUG: KASAN: vmalloc-out-of-bounds in reuseport_select_sock+0xedc/0x1220 net/core/sock_reuseport.c:596
Read of size 4 at addr ffffc9000051e004 by task slowme/10208
CPU: 6 UID: 1000 PID: 10208 Comm: slowme Not tainted 7.0.0-geb7ac95ff75e #32 PREEMPT(full)
Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
reuseport_select_sock+0xedc/0x1220 net/core/sock_reuseport.c:596
udp4_lib_lookup2+0x3bc/0x950 net/ipv4/udp.c:495
__udp4_lib_lookup+0x768/0xe20 net/ipv4/udp.c:723
__udp4_lib_lookup_skb+0x297/0x390 net/ipv4/udp.c:752
__udp4_lib_rcv+0x1312/0x2620 net/ipv4/udp.c:2752
ip_protocol_deliver_rcu+0x282/0x440 net/ipv4/ip_input.c:207
ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241
NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6181 [inline]
__netif_receive_skb net/core/dev.c:6294 [inline]
process_backlog+0xaa4/0x1960 net/core/dev.c:6645
__napi_poll+0xae/0x340 net/core/dev.c:7709
napi_poll net/core/dev.c:7772 [inline]
net_rx_action+0x5d7/0xf50 net/core/dev.c:7929
handle_softirqs+0x22b/0x870 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
</IRQ>
<TASK>
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline]
__dev_queue_xmit+0x1dd7/0x3710 net/core/dev.c:4890
neigh_output include/net/neighbour.h:556 [inline]
ip_finish_output2+0xca9/0x1070 net/ipv4/ip_output.c:237
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
ip_send_skb+0x45/0xc0 net/ipv4/ip_output.c:1508
udp_send_skb+0xb04/0x1510 net/ipv4/udp.c:1195
udp_sendmsg+0x1a71/0x2350 net/ipv4/udp.c:1485
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
__sys_sendto+0x554/0x680 net/socket.c:2206
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2209
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x160/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x415a2d
Code: b3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6bc31e41e8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f6bc31e4cdc RCX: 0000000000415a2d
RDX: 0000000000000001 RSI: 00007f6bc31e421f RDI: 0000000000000003
RBP: 00007f6bc31e4240 R08: 00007f6bc31e4220 R09: 0000000000000010
R10: 0000000000000000 R11:
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
HID: appleir: fix UAF on pending key_up_timer in remove()
appleir_remove() runs hid_hw_stop() before timer_delete_sync().
hid_hw_stop() synchronously unregisters the HID input device via
hid_disconnect() -> hidinput_disconnect() -> input_unregister_device(),
which drops the last reference and frees the underlying input_dev when
no userspace handle holds it open.
key_up_tick() reads appleir->input_dev and calls input_report_key() /
input_sync() on it. The timer is armed from appleir_raw_event() with
a HZ/8 (~125 ms) timeout on every keydown and key-repeat report. If a
key was pressed shortly before the device is disconnected, the timer
can fire after hid_hw_stop() has freed input_dev but before the
teardown drains it.
A simple reorder is not sufficient. Putting the timer drain first
still leaves a window where a USB URB completion (raw_event) running
during hid_hw_stop() can call mod_timer() and re-arm the timer, which
then fires after hidinput_disconnect() has freed input_dev. The same
URB-completion window also lets raw_event() reach key_up(), key_down()
and battery_flat() directly, all of which dereference
appleir->input_dev.
Introduce a 'removing' flag on struct appleir, gated by the existing
spinlock. appleir_remove() sets the flag under the lock and then
shuts down the timer with timer_shutdown_sync(), which both drains any
in-flight callback and permanently disables further mod_timer() calls.
appleir_raw_event() and key_up_tick() bail out early if the flag is
set, so no path can arm or run the timer, or dereference
appleir->input_dev, after remove() has started tearing down.
The keyrepeat and flatbattery branches of appleir_raw_event()
previously called into the input layer without holding the spinlock;
take it now so the flag check is well-defined. This incidentally
closes a pre-existing read-side race on appleir->current_key in the
keyrepeat branch.
This bug is structurally a sibling of commit 4db2af929279 ("HID:
appletb-kbd: fix UAF in inactivity-timer cleanup path") and has been
present since the driver was introduced. |
| In the Linux kernel, the following vulnerability has been resolved:
mm: shrinker: fix shrinker_info teardown race with expansion
expand_shrinker_info() iterates all visible memcgs under shrinker_mutex,
including memcgs that have not finished ->css_online() yet.
Once pn->shrinker_info has been published, teardown must stay serialized
with expand_shrinker_info() until that memcg is either fully online or no
longer visible to iteration. Today alloc_shrinker_info() breaks that rule
by dropping shrinker_mutex before freeing a partially initialized
shrinker_info array, which may cause the following race:
CPU0 CPU1
==== ====
css_create
--> list_add_tail_rcu(&css->sibling, &parent_css->children);
online_css
--> mem_cgroup_css_online
--> alloc_shrinker_info
--> alloc node0 info
rcu_assign_pointer(C->node0->shrinker_info, old0)
alloc node1 info -> FAIL -> goto err
mutex_unlock(shrinker_mutex)
shrinker_alloc()
--> shrinker_memcg_alloc
--> mutex_lock(shrinker_mutex)
expand_shrinker_info
--> mem_cgroup_iter see the memcg
expand_one_shrinker_info
--> old0 = C->node0->shrinker_info
memcpy(new->unit, old0->unit, ...);
free_shrinker_info
--> kvfree(old0);
/* double free !! */
kvfree_rcu(old0, rcu);
The same problem exists later in mem_cgroup_css_online(). If
alloc_shrinker_info() succeeds but a subsequent objcg allocation fails,
the free_objcg -> free_shrinker_info() unwind path tears down the already
published pn->shrinker_info arrays without shrinker_mutex. The
expand_one_shrinker_info() can race with that teardown in the same way,
leading to use-after-free or double-free of the old shrinker_info.
Fix this by serializing shrinker_info teardown with shrinker_mutex, and by
keeping alloc_shrinker_info() error cleanup inside the locked section. |
| In the Linux kernel, the following vulnerability has been resolved:
NTB: epf: Avoid calling pci_irq_vector() from hardirq context
ntb_epf_vec_isr() calls pci_irq_vector() in hardirq context to derive
the vector number. pci_irq_vector() calls msi_get_virq() that takes a
mutex and can therefore trigger "scheduling while atomic" splats:
BUG: scheduling while atomic: kworker/u33:0/55/0x00010001
...
Call trace:
...
schedule+0x38/0x110
schedule_preempt_disabled+0x28/0x50
__mutex_lock.constprop.0+0x848/0x908
__mutex_lock_slowpath+0x18/0x30
mutex_lock+0x4c/0x60
msi_domain_get_virq+0xe8/0x138
pci_irq_vector+0x2c/0x60
ntb_epf_vec_isr+0x28/0x120 [ntb_hw_epf]
__handle_irq_event_percpu+0x70/0x3a8
handle_irq_event+0x48/0x100
handle_edge_irq+0x100/0x1c8
...
Cache the Linux IRQ number for vector 0 when vectors are allocated and
use it as a base in the ISR. Running the ISR in a threaded IRQ handler
would also avoid the problem, but that would be unnecessary here. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref
l2cap_chan_timeout() runs asynchronously and accesses chan->conn. If
the connection is torn down while the timer is running or pending,
chan->conn can be freed, leading to a use-after-free when the timer
worker attempts to lock conn->lock:
| BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
| BUG: KASAN: slab-use-after-free in atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:4456 [inline]
| BUG: KASAN: slab-use-after-free in __mutex_trylock_fast kernel/locking/mutex.c:161 [inline]
| BUG: KASAN: slab-use-after-free in mutex_lock+0x4f/0xa0 kernel/locking/mutex.c:318
| Write of size 8 at addr ffff8881298d9550 by task kworker/2:1/83
|
| CPU: 2 UID: 0 PID: 83 Comm: kworker/2:1 Not tainted 7.1.0-rc6-next-20260601-dirty #6 PREEMPT(full)
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
| Workqueue: events l2cap_chan_timeout
| Call Trace:
| <TASK>
| instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
| atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:4456 [inline]
| __mutex_trylock_fast kernel/locking/mutex.c:161 [inline]
| mutex_lock+0x4f/0xa0 kernel/locking/mutex.c:318
| l2cap_chan_timeout+0x5d/0x1b0 net/bluetooth/l2cap_core.c:422
| process_one_work kernel/workqueue.c:3326 [inline]
| process_scheduled_works+0x7c8/0xfb0 kernel/workqueue.c:3409
| worker_thread+0x8a9/0xcf0 kernel/workqueue.c:3490
| kthread+0x346/0x430 kernel/kthread.c:436
| ret_from_fork+0x1a3/0x470 arch/x86/kernel/process.c:158
| ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
| </TASK>
|
| Allocated by task 320:
| l2cap_conn_add+0xa7/0x820 net/bluetooth/l2cap_core.c:7075
| l2cap_connect_cfm+0xdb/0xd70 net/bluetooth/l2cap_core.c:7452
| hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]
| hci_remote_features_evt+0x52f/0x9f0 net/bluetooth/hci_event.c:3760
| hci_event_func net/bluetooth/hci_event.c:7796 [inline]
| hci_event_packet+0x561/0xa70 net/bluetooth/hci_event.c:7847
| hci_rx_work+0x370/0x890 net/bluetooth/hci_core.c:4040
| process_one_work kernel/workqueue.c:3326 [inline]
| process_scheduled_works+0x7c8/0xfb0 kernel/workqueue.c:3409
| worker_thread+0x8a9/0xcf0 kernel/workqueue.c:3490
| kthread+0x346/0x430 kernel/kthread.c:436
| ret_from_fork+0x1a3/0x470 arch/x86/kernel/process.c:158
| ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
|
| Freed by task 322:
| hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline]
| hci_conn_hash_flush+0x101/0x1f0 net/bluetooth/hci_conn.c:2736
| hci_dev_close_sync+0x889/0xde0 net/bluetooth/hci_sync.c:5405
| hci_dev_do_close net/bluetooth/hci_core.c:502 [inline]
| hci_unregister_dev+0x1f7/0x370 net/bluetooth/hci_core.c:2679
| vhci_release+0x12a/0x180 drivers/bluetooth/hci_vhci.c:690
| __fput+0x369/0x890 fs/file_table.c:510
| task_work_run+0x160/0x1d0 kernel/task_work.c:233
| get_signal+0xf5b/0x1120 kernel/signal.c:2810
| arch_do_signal_or_restart+0x4d/0x600 arch/x86/kernel/signal.c:337
| __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
| exit_to_user_mode_loop+0x85/0x510 kernel/entry/common.c:98
| do_syscall_64+0x263/0x3d0 arch/x86/entry/syscall_64.c:100
| entry_SYSCALL_64_after_hwframe+0x77/0x7f
|
| The buggy address belongs to the object at ffff8881298d9400
| which belongs to the cache kmalloc-512 of size 512
| The buggy address is located 336 bytes inside of
| freed 512-byte region [ffff8881298d9400, ffff8881298d9600)
Fix it by having chan->conn hold a reference to l2cap_conn (via
l2cap_conn_get) when the channel is added to the connection, and
releasing it in the channel destructor. This ensures the l2cap_conn
remains alive as long as the channel exists.
A new FLAG_DEL channel flag is introduced to indicate that the ch
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
USB: legousbtower: fix use-after-free on disconnect race
mutex_unlock() may access the mutex structure after releasing the lock
and therefore cannot be used to manage lifetime of objects directly
(unlike spinlocks and refcounts). [1][2]
Use a kref to release the driver data to avoid use-after-free in
mutex_unlock() when release() races with disconnect().
[1] a51749ab34d9 ("locking/mutex: Document that mutex_unlock() is
non-atomic")
[2] 2b9d9e0a9ba0 ("locking/mutex: Clarify that mutex_unlock(), and most
other sleeping locks, can still use the lock object
after it's unlocked") |
| In the Linux kernel, the following vulnerability has been resolved:
USB: idmouse: fix use-after-free on disconnect race
mutex_unlock() may access the mutex structure after releasing the lock
and therefore cannot be used to manage lifetime of objects directly
(unlike spinlocks and refcounts). [1][2]
Use a kref to release the driver data to avoid use-after-free in
mutex_unlock() when release() races with disconnect().
[1] a51749ab34d9 ("locking/mutex: Document that mutex_unlock() is
non-atomic")
[2] 2b9d9e0a9ba0 ("locking/mutex: Clarify that mutex_unlock(), and most
other sleeping locks, can still use the lock object
after it's unlocked") |
| In the Linux kernel, the following vulnerability has been resolved:
irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT
On PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via
run_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0.
After irq_work_single() clears BUSY via atomic_cmpxchg(), it still
dereferences @work for irq_work_is_hard() and rcuwait_wake_up().
An irq_work_sync() caller on another CPU that enters after BUSY is cleared
can observe BUSY==0 immediately, return, and free the work before those
accesses complete — causing a use-after-free.
Fix this by wrapping run_irq_workd() in guard(rcu)() so that the entire
irq_work_single() execution is within an RCU read-side critical
section. Then add synchronize_rcu() in irq_work_sync() after
rcuwait_wait_event() to ensure the caller waits for the RCU grace period
before returning, preventing premature frees. |
| In the Linux kernel, the following vulnerability has been resolved:
zram: fix use-after-free in zram_bvec_write_partial()
zram_read_page() picks the sync or async backing device read path based on
whether the parent bio is NULL. zram_bvec_write_partial() passes its
parent bio down, so for ZRAM_WB slots the read is dispatched
asynchronously and zram_read_page() returns 0 while the bio is still in
flight. The caller then runs memcpy_from_bvec(), zram_write_page() and
__free_page() on the buffer, leaving the async read to write into a freed
page.
zram_bvec_read_partial() was switched to NULL in commit 4e3c87b9421d
("zram: fix synchronous reads") for the same reason; the write_partial
counterpart was missed. |
| In the Linux kernel, the following vulnerability has been resolved:
ovpn: tcp - use cached peer pointer in ovpn_tcp_close()
ovpn_tcp_close() loads the ovpn_socket via rcu_dereference_sk_user_data()
under rcu_read_lock(), takes a reference on sock->peer, caches the peer
pointer in a local, and drops the read lock. It then passes sock->peer
(rather than the cached local) to ovpn_peer_del(), re-dereferencing the
ovpn_socket after the RCU read section has ended.
Unlike ovpn_tcp_sendmsg(), which uses the same "load under RCU, use
after unlock" pattern but is protected by lock_sock() held across the
function, ovpn_tcp_close() runs without the socket lock: inet_release()
invokes sk_prot->close() without taking lock_sock first.
ovpn_socket_release() can therefore complete its kref_put -> detach ->
synchronize_rcu -> kfree(sock) sequence concurrently, in the window
after ovpn_tcp_close() drops rcu_read_lock() but before it dereferences
sock->peer. The synchronize_rcu() in ovpn_socket_release() protects
readers that use the dereferenced pointer inside the RCU read section,
not those that escape the pointer to a local and use it afterwards.
A reproducer follows the pattern of commit 94560267d6c4 ("ovpn: tcp -
don't deref NULL sk_socket member after tcp_close()"): trigger a peer
removal (keepalive expiration or netlink OVPN_CMD_DEL_PEER) at the same
moment userspace closes the TCP fd. That commit fixed the detach-side
of the same race window; this one fixes the close-side at a different
victim.
Tighten the entry block to read sock->peer exactly once into the cached
peer local, and route all subsequent uses (the hold check, the
ovpn_peer_del() call, and the prot->close() invocation) through that
local. sock->peer is only ever written once in ovpn_socket_new() under
lock_sock(), before rcu_assign_sk_user_data() publishes the ovpn_socket,
and is never reassigned afterwards - but the previous multi-read pattern
made that invariant implicit rather than explicit. The same multi-read
shape exists in ovpn_tcp_recvmsg(), ovpn_tcp_sendmsg(),
ovpn_tcp_data_ready() and ovpn_tcp_write_space(); those will be cleaned
up via a dedicated helper in a follow-up net-next series. |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: nau8821: Cancel delayed work on component remove
Attempting to unload the driver while a jack detection work is pending
would likely crash the kernel when it is eventually scheduled for
execution:
[ 1984.896308] BUG: unable to handle page fault for address: ffffffffc10c2a20
[...]
[ 1984.896388] Hardware name: Valve Jupiter/Jupiter, BIOS F7A0131 01/30/2024
[ 1984.896396] Workqueue: events nau8821_jdet_work [snd_soc_nau8821]
[ 1984.896414] RIP: 0010:__mutex_lock+0x9f/0x11d0
[...]
[ 1984.896504] Call Trace:
[ 1984.896511] <TASK>
[ 1984.896524] ? snd_soc_dapm_disable_pin+0x26/0x60 [snd_soc_core]
[ 1984.896572] ? snd_soc_dapm_disable_pin+0x26/0x60 [snd_soc_core]
[ 1984.896596] snd_soc_dapm_disable_pin+0x26/0x60 [snd_soc_core]
[ 1984.896622] nau8821_jdet_work+0xeb/0x1e0 [snd_soc_nau8821]
[ 1984.896636] process_one_work+0x211/0x590
[ 1984.896649] ? srso_return_thunk+0x5/0x5f
[ 1984.896670] worker_thread+0x1cd/0x3a0
Cancel unscheduled jdet_work or wait for its execution to finish before
the component driver gets removed. |
| A security regression (CVE-2006-5051) was discovered in OpenSSH's server (sshd). There is a race condition which can lead sshd to handle some signals in an unsafe manner. An unauthenticated, remote attacker may be able to trigger it by failing to authenticate within a set time period. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: synproxy: fix unaligned memory access in timestamp adjustment
Use get_unaligned_be32() and put_unaligned_be32() to safely read and
write the timestamp fields. This prevents performance degradation due to
unaligned memory access or even a crash on strict alignment
architectures.
This follows the implementation of timestamp parsing in the networking
stack at tcp_parse_options() and synproxy_parse_options(). |
| In the Linux kernel, the following vulnerability has been resolved:
Input: byd - synchronize timer deletion before freeing private data
byd_disconnect() uses timer_delete() before freeing the driver's private
data. This does not wait for a running byd_clear_touch() callback, which
dereferences the private data and its psmouse pointer. A callback racing
with disconnect can therefore access the private data after it has been
freed. The timer can also still be re-armed by byd_process_byte() while
the disconnect is in progress.
Use timer_shutdown_sync() before freeing the private data: it waits for
a running callback and turns any later re-arm attempt into a no-op. |
| In the Linux kernel, the following vulnerability has been resolved:
s390/vfio_ccw: Cancel existing workqueues
The initialization of the io_work and crw_work workqueues begs the
question of whether they should be un-initialized. Add the corresponding
cleanup tags in _release_dev to ensure work isn't dispatched after
the private struct is free'd. |
| In the Linux kernel, the following vulnerability has been resolved:
sched/psi: Shut down rtpoll_timer in psi_cgroup_free()
psi_schedule_rtpoll_work() is called locklessly from the scheduler hotpath
and can race psi_trigger_destroy() taking down the last rtpoll trigger under
rtpoll_trigger_lock:
psi_schedule_rtpoll_work() psi_trigger_destroy()
rcu_read_lock();
task = rcu_dereference(rtpoll_task);
rcu_assign_pointer(rtpoll_task, NULL);
timer_delete(&rtpoll_timer);
mod_timer(&rtpoll_timer, ...);
rcu_read_unlock();
synchronize_rcu();
kthread_stop(task_to_destroy);
The group can then be freed with the re-armed timer still pending, and
poll_timer_fn() runs on freed memory.
461daba06bdc ("psi: eliminate kthread_worker from psi trigger scheduling
mechanism") deleted the timer synchronously after the synchronize_rcu(),
which prevented this but raced trigger creation instead: the deletion could
cancel the timer that a new trigger set armed during the grace period and,
as creation also reinitialized the timer at the time, corrupt it.
8f91efd870ea ("psi: Fix race between psi_trigger_create/destroy") moved the
initialization into group_init() and the deletion into the locked section,
trading the creation races for the window above.
Neither placement in the destruction path works. A pending timer firing
while the group is alive is harmless though. poll_timer_fn() just wakes the
rtpoll waitqueue and doesn't re-arm itself. Bind the timer to the group's
lifetime instead and shut it down in psi_cgroup_free(). Nothing can arm it
by then. timer_shutdown_sync() because the timer is never armed again. |
| In the Linux kernel, the following vulnerability has been resolved:
enic: fix tx_hang_reset use-after-free on device removal
enic_remove() cancels the reset and change_mtu_work items but does not
cancel tx_hang_reset. A TX timeout that fires while the device is being
removed can schedule enic_tx_hang_reset() so that it runs after
free_netdev(), resulting in a use-after-free.
cancel_work_sync() alone is not sufficient here: the still-live watchdog
and notify paths can re-schedule these work items in the window between
the cancel and unregister_netdev(). Use disable_work_sync(), which
cancels the work and blocks any subsequent schedule_work() from
requeuing it, and apply it to the reset and change_mtu_work items as
well so the same requeue race is closed for all teardown work. |
