| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
virtio_input: stop callbacks before unregistering input device
virtinput_remove() unregisters the input device before resetting the
virtio device. virtinput_recv_events() drops vi->lock around input_event(),
so clearing vi->ready does not stop a callback that passed the entry check.
It can still use vi->idev, requeue buffers and kick the queue.
Reset first, as virtinput_freeze() already does. With the preceding core
change, reset waits for callbacks before input_unregister_device() can
free vi->idev. Recheck vi->ready after taking the lock again: keep draining
completed events so an input packet is not truncated, but stop requeueing
buffers and kicking the queue.
With evdev attached, input_unregister_handle() currently waits for an RCU
grace period, which also waits out IRQ callbacks. This masks the lifetime
bug on PCI and MMIO, but does not protect sleepable callbacks on other
transports. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btusb: Fix UAF of btusb_data by rx_work
btusb_close() and btusb_flush() cancel data->rx_work with the
asynchronous cancel_delayed_work(), so if btusb_rx_work() is already
running on another CPU it keeps running after the cancel returns.
btusb_disconnect() calls hci_unregister_dev(), which invokes
btusb_close(), and then frees the btusb_data. A still running
btusb_rx_work() then dereferences the freed data:
while ((skb = skb_dequeue(&data->acl_q)))
data->recv_acl(data->hdev, skb);
Use cancel_delayed_work_sync() instead. In btusb_close() the cancel also
has to happen after btusb_stop_traffic(), otherwise an URB completion
racing with the cancel can requeue the work right after it has been
waited for. |
| In the Linux kernel, the following vulnerability has been resolved:
configfs: pin the symlink target's dirent instead of chasing ->ci_dentry
create_link() reads the target's configfs_dirent from
item->ci_dentry->d_fsdata, relying on the item reference taken by
get_target(). That reference pins the item, not its dentry: the dentry is
pinned by DCACHE_PERSISTENT, which configfs_remove_dir() releases via
simple_rmdir() while the item is still alive. A symlink racing with rmdir
of its target can therefore find ->ci_dentry freed and its dirent
released, triggering WARN_ON(!atomic_read(&sd->s_count)) in configfs_get().
Take the dirent in get_target() as well, under ->d_lock and atomically
with the item reference, and pass it down to create_link(). A hashed
dentry has not been killed yet, so its ->d_fsdata reference keeps the
dirent alive there. |
| In the Linux kernel, the following vulnerability has been resolved:
configfs: unhash the dentry before dropping the item in rmdir
configfs_get_config_item() treats a hashed dentry as proof that
sd->s_element is a live config_item. configfs_rmdir() breaks that:
simple_rmdir() leaves the dentry hashed, the last reference to the item is
dropped right after, and the dentry is only unhashed by d_delete() once
->rmdir() has returned. configfs_symlink() resolves its target holding no
lock on it, so get_target() can land in that window:
BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90
get_target fs/configfs/symlink.c:128 [inline]
configfs_symlink+0x4ab/0x1030 fs/configfs/symlink.c:185
Unhash in configfs_remove_dir(), while the item is still guaranteed to be
there. A reference obtained just before that stays harmless, as
create_link() rechecks CONFIGFS_USET_DROPPING, already set by
configfs_detach_prep(). Both configfs_unregister_subsystem() paths
d_drop() after detaching, so this only makes rmdir match them. |
| In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Fix user-space data loss with MADV_FREE and THP
Some of users of Polars (a data analytics library) have lost production
data from this bug. They seem to have just the right combination of
huge pages, MADV_FREE and heavy reclaim pressure.
pmd_modify() masks the old value with (_HPAGE_CHG_MASK & ~_PAGE_DIRTY),
silently discarding the hardware dirty bit. The subsequent
pmd_mksaveddirty() call is supposed to transfer _PAGE_DIRTY into
_PAGE_SAVED_DIRTY when write-protecting, but the dirty bit was already
stripped from the value, so there is nothing left to transfer.
Contrast with pte_modify(), which keeps _PAGE_DIRTY_BITS in its mask,
and pud_modify(), which keeps _HPAGE_CHG_MASK untouched: pmd_modify()
is the odd one out. Any pmd_modify() on a writable, dirty PMD loses
the dirty state.
One visible consequence is data loss with MADV_FREE on PMD-mapped THP:
memset(buf, 0x5A, size); // PMD-mapped THP, PMD dirty
madvise(buf, size, MADV_FREE); // PMD cleaned but left writable,
// folio marked lazyfree
memset(buf, 0x5A, size); // hardware sets _PAGE_DIRTY again
mprotect(buf, size, PROT_READ); // pmd_modify() drops the dirty bit
mprotect(buf, size, PROT_READ|PROT_WRITE);
// ... memory pressure ...
Reclaim (e.g. under memcg pressure) then finds the lazyfree folio with
no dirty bit set anywhere and frees it in
__discard_anon_folio_pmd_locked(), even though the data was rewritten
after MADV_FREE; subsequent reads fault in fresh zero pages. NUMA
hinting alone can trigger the same loss, as do_huge_pmd_numa_page()
restores the PMD through pmd_modify() as well.
PMD-mapped file THPs are affected too: mprotect()/NUMA hinting dropping
the dirty bit means rewritten data is never written back.
Fix it by keeping _PAGE_DIRTY in the preserved mask, exactly like
pte_modify() and pud_modify() do. The existing
pmd_mksaveddirty()/pmd_clear_saveddirty() pair then performs the
hardware-dirty <-> saved-dirty transition based on the write bit,
preserving the shadow-stack encoding rules. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: fix fib6 walker UAF on seq stop
ipv6_route_iter_active() treats a walker in FWS_U at the table root as
already unlinked. fib6_del_route() can move a still-linked walker into
that same state when the current leaf is the last route at the root,
so ipv6_route_native_seq_stop() skips fib6_walker_unlink(). The seq
private object can then be freed while it remains on
net->ipv6.fib6_walkers. A later route deletion walks the dangling list
and uses the freed walker.
Use the list head as membership state and reinitialize it when
unlinking. Keep the existing w->node check so a never-started iterator
with a zeroed private object is not treated as linked.
The same stop helper is used by /proc/net/ipv6_route and by the BPF
ipv6_route iterator. The BPF show path only widens the race. |
| In the Linux kernel, the following vulnerability has been resolved:
reboot: fix cad_pid use-after-free race
cad_pid is a single kernel-wide struct pid pointer. proc_do_cad_pid()
reads it and passes it to pid_vnr() without protecting the lifetime of
the referenced struct pid. A concurrent writer can replace cad_pid and
drop the final reference to the old struct pid after the reader has
loaded the pointer but before pid_vnr() has finished dereferencing it,
causing a use-after-free.
kill_cad_pid() has the same lifetime race when it passes cad_pid to
kill_pid().
At the time this issue was reported, an unprivileged user could reach the
sysctl through user and PID namespaces because cad_pid was registered in
pid_table[]. Moving cad_pid back to the global reboot sysctl table
corrected that namespace and permission mismatch, but did not fix the
underlying lifetime race.
Fix this by treating cad_pid as an RCU-protected pointer at both read
sites and by waiting for a grace period before dropping the old reference
on the write side.
call_rcu(&old_pid->rcu, ...) cannot be used here because free_pid()
also queues pid->rcu; queueing the same rcu_head twice can corrupt the
RCU callback list.
Original KASAN crash stack:
kernel/pid.c:545 pid_nr_ns() # reads freed pid->level
kernel/pid.c:556 pid_vnr() # calls pid_nr_ns()
kernel/pid.c:775 proc_do_cad_pid() # calls pid_vnr(cad_pid) |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Set the trace clock before registering the histogram trigger
hist_register_trigger() puts the trigger on the global named_triggers
list in cmd_ops->init(), and only then sets the trace clock:
if (data->cmd_ops->init) {
ret = data->cmd_ops->init(data);
if (ret < 0)
goto out;
}
if (hist_data->enable_timestamps) {
ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
if (ret) {
hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
goto out;
}
The clock string is not checked anywhere before that call, so a named
trigger using common_timestamp with an unknown clock fails after it has
already become findable. event_hist_trigger_parse() then frees it
without taking it off the list, and the next lookup by name reads the
freed object:
~# cd /sys/kernel/tracing/events/sched/sched_switch
~# echo 'hist:name=foo:keys=common_pid:ts=common_timestamp:clock=bogus' > trigger
bash: echo: write error: Invalid argument
~# echo 'hist:name=foo:keys=common_pid' > trigger
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff88800915d760 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0x900
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 63:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160
Set the clock before the trigger is registered, so that nothing which
can fail runs after it is published, the way commit 6f86bdeab633
("tracing: Fix bad hist from corrupting named_triggers list") moved the
registration below the rest of the setup.
tracing_set_filter_buffering() is reference counted, so the init failure
path has to drop the reference that the clock block now takes first. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Take trace_array reference when opening a tracer options file
When a tracer option file is opened, it is passed a descriptor that points
to an element on the trace_array's topts array. This element has
information to find the trace array and other information. It uses this
element to take a reference of the trace_array so that the trace_array
does not get removed while this file is opened.
Unfortunately, there's a race condition where the element itself could be
freed by the removal of the instance the trace_array represents causing a
use-after-free as this element that is used to find the trace_array to
increment its reference counter is also freed when the instance is
removed.
To solve this, add a trace_array_tracer_options_get() helper function that
will take the address of the element that is passed to the open function
by the inode->i_private pointer and search all the trace_arrays under a
lock to find the one that the element's address is in the range of the
trace_arrays topts array elements. When a match happens, that trace_array's
reference would be increased.
Note, there's a race where if an admin was deleting and creating trace
instances at the same time and the memory of the old trace_array's array
matched the memory of the new trace_array that it could in theory open the
option from the wrong trace array. But we do not care because it would be
stupid to perform that kind of action. As long as the only thing that can
happen is that the option from the wrong trace array is used and doesn't
crash the kernel it will only make the user confused. But if they are
doing something stupid like this, they are already confused, so no harm
done. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing/user_events: Don't destroy fields when event removal fails
destroy_user_event() destroys the event's fields before attempting to
remove the trace event call. If user_event_set_call_visible() fails,
e.g. because the event is still enabled and trace_remove_event_call()
returns -EBUSY, the event is left registered with an irreversibly
destroyed field list. Any subsequent interaction with the event then
operates on an empty field list while it is still fully visible in
tracefs.
Move the field destruction after the call removal, and splice the
field list back onto the event when the removal fails so the event
remains in a consistent state. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Take the reference before publishing the named histogram trigger
event_hist_trigger_named_init() puts the trigger on the global
named_triggers list and only then takes the reference on the trigger it
shares its histogram with:
data->ref++;
save_named_trigger(data->named_data->name, data);
ret = event_hist_trigger_init(data->named_data);
if (ret < 0) {
kfree(data->cmd_ops);
data->cmd_ops = &trigger_hist_cmd;
}
return ret;
event_hist_trigger_init() fails when alloc_hist_pad() cannot allocate, and
nothing takes the trigger back off the list on the way out.
event_hist_trigger_parse() frees it, and the next lookup by name reads the
freed object:
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff888009346860 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0xa00
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 67:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160
Do the reference first and publish once it has succeeded, so that nothing
which can fail runs after the trigger becomes findable. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Undo the registration when enabling the histogram trigger fails
Commit 6f86bdeab633 ("tracing: Fix bad hist from corrupting named_triggers
list") described how a trigger that is registered but not on file->triggers
ends up freed while still on the global named_triggers list, and moved the
registration down so that hist_trigger_enable() follows it immediately. One
path still gets there. hist_trigger_enable() adds the trigger and takes it
straight back out when the event cannot be enabled:
list_add_tail_rcu(&data->list, &file->triggers);
update_cond_flag(file);
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
update_cond_flag(file);
ret--;
}
so the list walk in hist_unregister_trigger() matches nothing, test stays
NULL, and the ->free() that would call del_named_trigger() is skipped.
out_unreg falls through to out_free, which frees the trigger anyway:
BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff8880091d3160 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0xa00
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 69:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160
Leave the trigger where hist_unregister_trigger() can find it and let that
undo the registration, which is the only code that knows all of what
cmd_ops->init() took: the named list entry, the hist_pad reference, the
reference on the trigger a named histogram is shared with, and the copied
cmd_ops. It also pairs the failed trace_event_trigger_enable_disable(),
whose sm_ref and buffered event reference are otherwise left behind.
Since ->free() releases trigger_data and, for a trigger that does not share
its histogram, hist_data with it, out_unreg can no longer fall through to
out_free. For a trigger that does share, hist_register_trigger() has
already destroyed the caller's hist_data, so the fall-through was reading
freed memory there as well.
Move the enable_timestamps check in hist_unregister_trigger() above the
->free() call for the same reason: hist_data does not outlive it once the
trigger being removed is the one that owns it. |
| In the Linux kernel, the following vulnerability has been resolved:
genetlink: pin family module during policy dump
The generic netlink controller's policy dump keeps pointers to the target
family's operation and policy tables in its callback state. A dump may be
split across multiple skbs and remain pending after the initial request.
Netlink pins the module which owns the dump callback, but in this case
that is the controller's owner rather than the target family's owner. The
target family can consequently be unregistered and its module unloaded
while a policy dump is pending. Advancing the dump then dereferences
policy memory from the unloaded module.
Take a reference to the target family's module when the dump starts.
Drop it from the error and done paths. This matches the lifetime for which
the dump context retains the family and policy pointers. |
| In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix use-after-free of the flow table mask array
tbl_mask_array_realloc() retires the old mask_array before it stops being
reachable:
old = ovsl_dereference(tbl->mask_array);
if (old) {
...
call_rcu(&old->rcu, mask_array_rcu_cb);
}
rcu_assign_pointer(tbl->mask_array, new);
call_rcu() only waits for read-side critical sections already in flight.
tbl->mask_array still points at old between the call_rcu() and the
rcu_assign_pointer(), so a reader entering ovs_flow_tbl_lookup_stats() in
that window picks up old in a fresh critical section that the pending
grace period does not cover.
tbl_mask_array_realloc() runs in process context under ovs_mutex, so the
window is preemptible and can outlast the grace period. Then
mask_array_rcu_cb() frees old before the swap runs:
BUG: KASAN: slab-use-after-free in flow_lookup.constprop.0+0x2bf/0x2f0
Read of size 8 at addr ffff888020b3e018 by task poc/741
flow_lookup.constprop.0+0x2bf/0x2f0
ovs_flow_tbl_lookup_stats+0x4a3/0x5c0
ovs_dp_process_packet+0x19c/0x710
ovs_vport_receive+0x243/0x390
internal_dev_xmit+0x81/0x170
Freed by task 728:
kfree+0x16a/0x4e0
rcu_core+0x853/0x1030
Publish the new array before retiring the old one. The kfree_rcu() that
call_rcu() replaced ran after the swap. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: cttimeout: prevent UAF during module unload
nf_ct_set_timeout() protects the timeout hook dereference and policy lookup
with rcu_read_lock(). cttimeout_exit(), however, unregisters the per-net
operations before it clears the hook.
This allows the following interleaving:
CPU 0 CPU 1
cttimeout_exit() nf_ct_set_timeout()
unregister_pernet_subsys() rcu_read_lock()
kfree(pernet) h = nf_ct_timeout_hook
h->timeout_find_get()
nfct_timeout_pernet()
The hook still points to ctnl_timeout_find_get() when CPU 1 looks up the
already freed per-net timeout list. KASAN reported:
BUG: KASAN: slab-use-after-free in ctnl_timeout_find_get
Read of size 8 by task poc/90
Call Trace:
ctnl_timeout_find_get+0x271/0x2a0 [nfnetlink_cttimeout]
nf_ct_set_timeout+0x7b/0x3c0
xt_ct_tg_check+0x724/0xb20
xt_check_target+0x234/0xa90
do_ipt_set_ctl+0x570/0x1270
Allocated by task 89:
__kmalloc_noprof+0x16e/0x460
ops_init+0x6d/0x420
register_pernet_operations+0x2f6/0x670
Freed by task 91:
kfree+0x131/0x390
ops_undo_list+0x3d4/0x730
unregister_pernet_operations+0x232/0x490
unregister_pernet_subsys+0x1c/0x30
cttimeout_exit+0x52/0x970 [nfnetlink_cttimeout]
Clear the hook and wait for existing readers before unregistering the
per-net operations. This blocks new policy lookups and ensures readers that
observed the hook finish before the per-net storage is freed. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_log: unregister loggers before per-net teardown
nf_log_syslog and nfnetlink_log unregister their per-network namespace
operations before unregistering their global logger backends. This
leaves a window where a sysctl or netlink writer can rebind the still-
registered logger after the per-net pre-exit callback cleared the old
selection.
The race looks like this:
CPU 0 CPU 1
---- ----
unregister_pernet_subsys()
nf_log_unset(net, logger)
net->nf.nf_loggers[pf] = NULL
lock nf_log_mutex
find logger in loggers[][]
net->nf.nf_loggers[pf] = logger
unlock nf_log_mutex
nf_log_unregister(logger)
lock nf_log_mutex
loggers[pf][type] = NULL
unlock nf_log_mutex
synchronize_rcu()
module exit returns
module core frees backend memory
Later, a sysctl read or packet logging operation can dereference the
stale per-net logger pointer.
Fix this by unregistering the global logger backends before tearing down
per-net state. Once the global registrations are gone, later writers can
no longer rebind the logger. unregister_pernet_subsys() already waits
for an RCU grace period after the pre-exit callback clears the per-net
selection, while nf_log_unregister() continues to cover readers of the
global logger table.
Apply this ordering fix to both nf_log backends that combine per-net
teardown with global logger registration. |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: vfb: defer cleanup until the last reference
FBIOGETCMAP takes a shallow snapshot of info->cmap and performs the
usercopy after dropping info->lock. vfb_remove() frees the colormap
immediately after unregistering the framebuffer, even when an open file
still holds a reference to fb_info. A concurrent driver unbind can
therefore free the colormap while the ioctl copies it to userspace.
KASAN reports:
BUG: KASAN: slab-use-after-free in _copy_to_user
Read of size 512 by task poc/125
_copy_to_user (./include/linux/instrumented.h:129 ./include/linux/uaccess.h:201 lib/usercopy.c:24)
fb_cmap_to_user (./include/linux/uaccess.h:230 drivers/video/fbdev/core/fbcmap.c:211)
do_fb_ioctl (drivers/video/fbdev/core/fb_chrdev.c:114)
Allocated by task 1:
fb_alloc_cmap_gfp (./include/linux/slab.h:973 ./include/linux/slab.h:1290 drivers/video/fbdev/core/fbcmap.c:108)
vfb_probe (drivers/video/fbdev/vfb.c:459)
Freed by task 124:
fb_dealloc_cmap (drivers/video/fbdev/core/fbcmap.c:151)
vfb_remove (drivers/video/fbdev/vfb.c:489)
unregister_framebuffer() drops the registration reference, and fbdev calls
fb_destroy after the last put_fb_info(). Move the registered framebuffer's
cleanup into an fb_destroy callback so its colormap and screen buffer stay
alive until all file references have been released. |
| In the Linux kernel, the following vulnerability has been resolved:
idpf: disable DIM work before freeing q_vectors
idpf never drains the Tx/Rx DIM works before freeing the memory they
live in. tx_dim and rx_dim are embedded in struct idpf_q_vector, they
are queued from the NAPI poll via net_dim(), and idpf_vport_intr_rel()
ends with kfree(rsrc->q_vectors). Nothing in the driver cancels them.
idpf_tx_dim_work() and idpf_rx_dim_work() then run on freed memory:
idpf_vport_intr_write_itr() writes the ITR register through
q_vector->intr_reg.tx_itr / rx_itr, void __iomem pointers loaded out of
the freed q_vector. No configuration is needed to get there --
IDPF_ITR_IS_DYNAMIC() is defined as (itr_mode) and idpf_vport_alloc()
initialises both modes to IDPF_ITR_DYNAMIC.
Draining after idpf_vport_intr_napi_dis_all() is not enough on its own.
idpf_net_dim() is called from inside the
"if (napi_complete_done(napi, work_done))" branch of the poll, and
napi_complete_done() has already cleared NAPIF_STATE_SCHED by then.
napi_disable_locked() waits only while (val & (NAPIF_STATE_SCHED |
NAPIF_STATE_NPSVC)), so napi_disable() can return while the poll tail is
still queueing the work, and a plain cancel_work_sync() would be
re-armed behind the drain.
Use disable_work_sync(): schedule_work() on a work with a non-zero
disable count is dropped by clear_pending_if_disabled() before
__queue_work() is reached.
Move idpf_init_dim() to idpf_vport_intr_alloc() so the works are
initialised on every path that can reach the drain -- the three
"goto intr_deinit" sites between idpf_vport_intr_init() and
idpf_vport_intr_ena() get there without the enable side having run.
Nothing re-enables them: rsrc->q_vectors is freed on every exit from
idpf_vport_open() and on every idpf_vport_stop(), so the count dies with
the object.
It is a race, not a deterministic failure -- net_dim() only schedules
once DIM_NEVENTS events have accumulated and the profile index changes.
A KASAN ifup/ifdown loop under load is the way to see it. |
| In the Linux kernel, the following vulnerability has been resolved:
mac802154: fix use-after-free of sdata via queued RX frames
The RX softirq producer ieee802154_subif_frame() queues received beacon
and MAC-command frames onto local->rx_beacon_list / rx_mac_cmd_list and
schedules a process-context worker, storing a raw mac_pkt->sdata (and
skb->dev == sdata->dev) with neither a reference nor any locking:
- the lists have no lock: the softirq producer list_add_tail()s while the
mac_wq worker list_del()s, so sibling interfaces on the same phy corrupt
the list;
- the workers dereference the interface after it may have been freed.
mac802154_rx_mac_cmd_worker() touches mac_pkt->sdata directly, and
mac802154_rx_beacon_worker() -> mac802154_process_beacon() dereferences
skb->dev (== sdata->dev). Removing an interface frees its sdata
(netdev_priv) while a queued frame still points at it, so a later worker
run is a use-after-free.
Reproduced under KASAN by flooding a victim interface with MAC command
frames and removing it (the beacon path is the same class via skb->dev):
BUG: KASAN: slab-use-after-free in mac802154_rx_mac_cmd_worker+0x463/0x630 [mac802154]
Read of size 4 at addr ffff888002f9ea18 by task kworker/u8:1/31
Workqueue: phy0-mac-cmds mac802154_rx_mac_cmd_worker [mac802154]
Call Trace:
mac802154_rx_mac_cmd_worker+0x463/0x630 [mac802154]
process_one_work+0x611/0xe80
worker_thread+0x52e/0xdc0
kthread+0x30c/0x630
ret_from_fork+0x2fd/0x3e0
Fix both lists together:
- add local->rx_lock and take it around every list access: the softirq
producer (plain spin_lock, softirq context) and the workers and flush
(spin_lock_bh, process context);
- pin the interface for the lifetime of a queued frame with
netdev_hold()/netdev_put(), so the worker can safely dereference sdata /
skb->dev even while the interface is being removed;
- dequeue under the lock at the head and loop-drain the whole list in the
workers (they previously processed one frame per run and relied on a
later enqueue to drain the rest);
- drop not-yet-started frames of an interface before it is unregistered,
from ieee802154_if_remove() (after the RCU grace period) and from the
ieee802154_remove_interfaces() loop -- the latter is the whole-phy
teardown path, which does not go through ieee802154_if_remove().
An in-flight worker that already dequeued a frame keeps its own netdev
reference; unregister_netdevice() then waits it out in netdev_run_todo(),
which runs at rtnl_unlock() (rtnl released) and after the interface has
been closed, so it does not pin rtnl. A worker blocked in an association
TX only delays that one interface's unregister (the usual "waiting for %s
to become free"), it does not hold rtnl. netdev_hold() is used for this
reason instead of a cancel_work_sync() under rtnl, which would block on
the worker's unbounded MLME TX wait via ieee802154_sync_queue().
The mac-command worker additionally skips processing for a stopped
interface (ieee802154_sdata_running()), avoiding a needless association
response during teardown. |
| In the Linux kernel, the following vulnerability has been resolved:
landlock: Fix use-after-free of the source's parent directory
current_check_refer_path() reads old_dentry->d_parent without holding a
reference nor a lock on it, and then dereferences it in
collect_domain_accesses() and in the audit record.
A reference on a child does not pin its parent: __d_move() reassigns
dentry->d_parent and drops the reference the child held on its former
parent. hook_path_rename() is not affected because the rename path
calls lock_rename() before the hook, so the source cannot be reparented
under it. hook_path_link() has no such protection: filename_linkat()
holds a reference on the source dentry but neither locks nor references
its parent, so a concurrent rename(2) can reparent the source while
security_path_link() runs, and the former parent can then be removed and
freed while the hook walks it.
A process can trigger this after entering a Landlock domain that handles
at least one filesystem access right. The process can then race a
linkat(2) loop against rename(2) and rmdir(2):
BUG: KASAN: slab-use-after-free in collect_domain_accesses+0x278/0x290
Read of size 4 at addr ffff888160bd53f4 by task llrepro2/549
collect_domain_accesses+0x278/0x290
current_check_refer_path+0x952/0x1120
security_path_link+0x1be/0x320
filename_linkat+0x342/0x6d0
__x64_sys_linkat+0xfa/0x150
Freed by task 562:
kmem_cache_free+0x139/0x4c0
i_callback+0x4b/0x80
rcu_core+0x7dc/0x10a0
Take a reference on the dentry selected as the source parent, using
dget() for the common-mount-root case and dget_parent() otherwise.
Release it after the hierarchy walk and synchronous audit logging.
[mic: Clarify the caller, reachability, and reference handling] |
