| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix socket use-after-free during link group termination
__smc_lgr_terminate() drops conns_lock after finding a connection in
lgr->conns_all, but before taking a reference on its socket. The connection
is embedded in the socket, and its registration reference protects it only
while the connection remains in the tree.
A concurrent close can unregister the connection and drop that reference,
freeing the socket before the termination worker reaches sock_hold().
The race is reachable when close overlaps link group termination.
Local stress testing reproduced the use-after-free and KASAN reported:
BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc]
Write of size 4 by task kworker/3:3
Workqueue: events smc_lgr_terminate_work [smc]
__smc_lgr_terminate.part.0 [smc]
The socket was allocated by smc_create(), freed through
slab_free_after_rcu_debug(), and was followed by:
refcount_t: addition on 0; use-after-free.
__smc_lgr_terminate.part.0 [smc]
Take the socket reference while conns_lock still protects the tree entry.
The unregister path then cannot drop the last reference until termination
has finished using the socket. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: ipset: do not update comments from kernel-side hash adds
mtype_resize() copies comment pointers with memcpy(), not the comment
objects themselves. During the window after an entry has been copied but
before the table swap and backlog replay, the old table is still
published for packet-side updates while the replacement-table entry
already holds the same ip_set_comment_rcu pointer.
If xt_SET --add-set ... --exist hits that old entry in this window,
mtype_add() calls ip_set_init_comment() even though packet-side adds
carry no comment payload. That call frees the shared comment through the
old entry, so the replacement-table entry now holds a stale pointer.
When the queued add is replayed on the new table, mtype_add() calls
ip_set_init_comment() again and strlen() dereferences the stale pointer.
Fix this in mtype_add() by skipping ip_set_init_comment() when
ext->target marks a packet-side add. Userspace adds still update
comments, while packet-side adds can no longer free comment storage
shared with a resize copy. |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: avoid use-after-free in poll trace queue dumps
TIPC socket tracepoints dump queue state through tipc_sk_dump(). Most
queue-dump callsites already serialize that walk under the socket lock or
sk->sk_lock.slock, but tipc_poll() calls trace_tipc_sk_poll(...,
TIPC_DUMP_ALL, ...) without holding either lock.
That lets the poll trace path reach tipc_list_dump() and backlog head/tail
dumping while another context dequeues and frees an skb, leaving the trace
helper dereferencing a stale queue entry.
Stop the unlocked poll trace site from requesting queue dumps. Other queue
dump trace callsites keep their existing output under the locking they
already provide, while poll still emits the event itself without walking
live queue members from an unlocked context. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: fix tid_tx use-after-free on BA session stop
ieee80211_stop_tx_ba_cb() hands tid_tx to kfree_rcu() through
ieee80211_remove_tid_tx(), and then reads tid_tx->ndp after dropping
sta->lock:
ieee80211_remove_tid_tx(sta, tid); /* kfree_rcu(tid_tx, rcu_head) */
...
spin_unlock_bh(&sta->lock);
if (start_txq)
ieee80211_agg_start_txq(sta, tid, false);
if (send_delba)
ieee80211_send_delba(..., tid_tx->ndp);
That read is not covered by an RCU read-side critical section, and it runs
in preemptible process context: both callers hold the wiphy mutex, reaching
it either from the ieee80211_ba_session_work() wiphy work or from
ieee80211_sta_tear_down_BA_sessions() during station teardown.
Softirqs can run in that window too, both from the local_bh_enable() that
ends ieee80211_agg_start_txq() and from any interrupt exit, so the RCU
callback can free tid_tx before the read.
Driving the function from a test module with the grace period forced into
that window, KASAN reports the read, and the free arrives on the ordinary
RCU softirq path:
BUG: KASAN: slab-use-after-free in ieee80211_stop_tx_ba_cb+0x3cd/0x400
Read of size 1 at addr ffff888002b9f52e by task kworker/0:1/10
[...]
Freed by task 57:
__kasan_slab_free+0x47/0x70
__rcu_free_sheaf_prepare+0x70/0x250
rcu_free_sheaf_nobarn+0x18/0x40
rcu_core+0x426/0x1310
handle_softirqs+0x144/0x590
__irq_exit_rcu+0xea/0x150
irq_exit_rcu+0x9/0x20
sysvec_apic_timer_interrupt+0x6b/0x80
asm_sysvec_apic_timer_interrupt+0x1a/0x20
send_delba is only set when tx_stop is set, which happens for
AGG_STOP_LOCAL_REQUEST alone, so this is reached on local teardown -
session idle timeout, PTK rekey, suspend, HW reconfig - and not from a
peer's DELBA.
Read ndp into a local before the session is freed, while sta->lock is still
held. tid_tx->ndp has a single writer, in
ieee80211_tx_ba_session_handle_start(), which cannot run concurrently here:
both paths are serialised by the wiphy mutex, and the session is already
marked HT_AGG_STATE_STOPPING at this point. tid_tx->ndp is also the only
tid_tx dereference left after ieee80211_remove_tid_tx() in this function.
[move/change the comment a bit to be more general not just on ndp,
initialize ndp directly] |
| In the Linux kernel, the following vulnerability has been resolved:
mm/huge_memory: unlock i_mmap_rwsem before releasing after-split folios
__folio_split() keeps dereferencing the mapping after the split:
shmem_uncharge(mapping->host) and remap_page() while the folios are still
frozen/locked, and i_mmap_unlock_read(mapping) at the very end, after the
after-split folios have been unlocked and freed.
Nothing holds an inode reference across that. The split relies on @folio
-- which the beyond-EOF drop loop never removes, as it starts at
folio_next(folio) -- staying locked and in the page cache to hold off
eviction. But the unlock loop unlocks @folio before i_mmap_unlock_read()
runs. If the caller's @lock_at is a tail beyond EOF, as memory_failure()
passes when splitting a poisoned tail of a shmem THP that reaches past
i_size during truncation, it too is gone from the page cache; so once
@folio is unlocked no locked, in-cache folio pins the inode, and a
concurrent final iput() can evict and RCU-free it before
i_mmap_unlock_read() touches i_mmap_rwsem:
BUG: KASAN: slab-use-after-free in __up_read+0x634/0x790
i_mmap_unlock_read include/linux/fs.h:537 [inline]
__folio_split+0x732/0x1640 mm/huge_memory.c:4100
try_to_split_thp_page+0xab/0x390 mm/memory-failure.c:1675
memory_failure+0x1394/0x26e0 mm/memory-failure.c:2470
Freed by task 4601:
shmem_free_in_core_inode+0x54/0xb0 mm/shmem.c:5177
evict+0x57f/0xac0 fs/inode.c:870
Do every mapping dereference while @folio still pins the inode: drop
i_mmap_rwsem right after remap_page(), before the loop that unlocks and
frees the after-split folios, and clear @mapping so the exit path does not
unlock it again. shmem_uncharge() and remap_page() already run before
that point, so after this nothing past the unlock loop touches the inode
or the mapping.
This is now a rule the split depends on, alongside keeping @folio frozen
until the page cache is updated: no inode or mapping dereference once the
after-split folios start being unlocked. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/page_reporting: use system_freezable_wq to fix UAF during suspend
During PM freeze (e.g. S3 suspend or S4 hibernation), device drivers like
virtio_balloon reset their underlying virtio devices and delete their
virtqueues via vdev->config->del_vqs().
However, page reporting work (page_reporting_process) was scheduled on the
global system_wq. Because system_wq lacks the WQ_FREEZABLE flag, the PM
freezer skips it, leaving page_reporting_process active during suspend.
If pages are freed into the buddy allocator while suspending (for example,
when core MM invokes the balloon shrinker during S4 hibernation image
saving), page reporting triggers virtballoon_free_page_report() on deleted
virtqueues, resulting in a Use-After-Free / General Protection Fault:
[ 196.795226] general protection fault, probably for non-canonical address 0xaa1436fe70dae6df: 0000 [#1] SMP NOPTI
[ 196.825967] Workqueue: events page_reporting_process
[ 196.831038] RIP: 0010:virtqueue_add_split+0x233/0x4c0 [virtio_ring]
[ 196.927073] virtballoon_free_page_report+0x3a/0xe0 [virtio_balloon]
[ 196.946943] page_reporting_process+0x370/0x4f0
Fix this by switching page reporting work to system_freezable_wq. This
ensures that the PM freezer pauses page_reporting_process before device
drivers destroy their reporting virtqueues. Because the reporting worker
is frozen, memory reclamation/freeing (e.g. via shrinker execution) can
safely return pages to MM during freeze without triggering unfrozen
reporting work on deleted virtqueues.
This aligns with the driver's existing design. The comment in
virtballoon_freeze() states:
/*
* The workqueue is already frozen by the PM core before this
* function is called.
*/
Testing:
I have verified these fixes using Google’s virtualization infrastructure
by running continuous suspend/resume iterations (40+ cycles) while
churning memory using stress-ng (`stress-ng --vm 4 --vm-bytes 60%
--timeout 1`) to constantly create free pages for the buddy allocator. We
also set the `page_reporting_order` parameter to 0 to make the page
reporting worker highly sensitive, forcing it to pick up any 4K free
pages. This confirmed that the UAF crashes are no longer reproducible. |
| In the Linux kernel, the following vulnerability has been resolved:
net: bridge: stop fast-leave after deleting a port group
br_multicast_leave_group() iterates mp->ports with pp = &p->next in
its fast-leave path. After br_multicast_del_pg() removes p,
continuing the loop advances pp through the deleted entry.
If multicast-to-unicast was enabled, the bridge can hold multiple port
groups for the same port and group with different source MAC
addresses. Once multicast-to-unicast is disabled,
br_port_group_equal() matches those entries by port only. A fast leave
can then delete one entry and continue from its stale next pointer,
leaving mp->ports pointing at a deleted port group.
Fast leave only needs to remove one matching port group. Break after
br_multicast_del_pg() so the loop stops before dereferencing the
removed entry. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Check return value of __register_event() in trace_module_add_events()
trace_module_add_events() ignores the return value of __register_event()
and unconditionally calls __add_event_to_tracers() for each event.
If __register_event() fails (for example, if event_init() fails), the
trace_event_call is not added to ftrace_events list, but
__add_event_to_tracers() still creates a trace_event_file pointing to it.
If module loading subsequently fails and module memory is freed, tracing
state retains a stale trace_event_call pointer in trace_event_file,
leading to a use-after-free when tracefs or tracing subsystem operations
are later executed.
Fix this by checking the return value of __register_event() and only
calling __add_event_to_tracers() if event registration succeeded. |
| In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix potential UAF on meter attach failure
While attaching a newly created meter attach_meter() function makes
the new meter visible to other CPUs but can still fail afterwards.
On failure, it detaches the meter back and returns an error.
However, this is an unexpected behavior for the ovs_meter_cmd_set()
that uses a plain kfree(meter) on attach failure without waiting for
RCU readers to stop using it, assuming it was never visible.
This is never a problem for ovs-vswitchd as it always creates meters
before creating any flows that use them. But the UAF can be triggered
with a custom application using uAPI:
BUG: KASAN: slab-use-after-free in ovs_meter_execute (net/openvswitch/meter.c:653)
Read of size 8 at addr ffff88810d152650 by task meter/2508
Call Trace:
ovs_meter_execute (net/openvswitch/meter.c:653)
do_execute_actions (net/openvswitch/actions.c:1407)
ovs_execute_actions (net/openvswitch/actions.c:1584)
ovs_packet_cmd_execute (net/openvswitch/datapath.c:703)
...
netlink_sendmsg (af_netlink.c:1900)
Allocated by task 2519:
__kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)
ovs_meter_cmd_set (net/openvswitch/meter.c:422)
...
netlink_sendmsg (af_netlink.c:1900)
Freed by task 2519:
kfree (mm/slub.c:2705 mm/slub.c:6405 mm/slub.c:6720)
ovs_meter_cmd_set (net/openvswitch/meter.c:479)
...
netlink_sendmsg (af_netlink.c:1900)
Fix that by making sure attach_meter() doesn't make the meter visible
until all the checks are done and the function can't fail anymore.
This also makes sure the "hash" value is calculated after the potential
re-sizing of the table.
Reported by Trend Micro's Zero Day Initiative as ZDI-CAN-31642. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amd/pm: fix pptable use-after-free
amdgpu_dpm_get_pp_table() returns a pointer to a driver-owned power table
after dropping adev->pm.mutex. The sysfs path then copies from that pointer.
A concurrent pp_table write can replace and free the allocation during the
copy, causing a use-after-free.
Change the DPM interface to copy into caller-provided storage while the mutex
is held. Keep the size-only query for attribute discovery without exposing
the driver-owned pointer.
(cherry picked from commit f6eed7acfd30099ef7baeb6ba45bb59daad80631) |
| In the Linux kernel, the following vulnerability has been resolved:
rxrpc: serialize kernel accept preallocation with socket teardown
rxrpc_kernel_charge_accept() reads rx->backlog without any
socket/backlog synchronization and passes that raw pointer into
rxrpc_service_prealloc_one(). A concurrent rxrpc_discard_prealloc()
sets rx->backlog = NULL and frees the backlog rings, so a kernel
preallocation worker can keep using a freed struct rxrpc_backlog
while updating *_backlog_head/tail and array slots.
Serialize the state check and backlog lookup with the socket lock,
and reject kernel preallocation once teardown has disabled
listening or discarded the service backlog. |
| In the Linux kernel, the following vulnerability has been resolved:
configfs_lookup(): don't leave ->s_dentry dangling on failure
Normally ->s_dentry is cleared when dentry it's pointing to becomes
negative (on eviction, realistically). However, that only happens
if dentry gets to be positive in the first place; in case of inode
allocation failure dentry never becomes positive, so ->d_iput()
is not called at all.
We do part of what normally would've been done by configfs_d_iput()
(dropping the reference to configfs_dirent) manually, but we do
not clear ->s_dentry there. Sloppy as it is, it does not matter in
case of configfs_create_{dir,link}() - there configfs_dirent does
not survive dropping the sole reference to it.
However, for configfs_lookup() it *does* survive, with a dangling
pointer to soon to be freed dentry sitting it its ->s_dentry.
Subsequent getdents(2) in that directory will end up dereferencing
that pointer in order to pick the inode number. Use after free...
This is the minimal fix; the right approach is to set the linkage
between dentry and configfs_dirent only after we know that we have
an inode, but that takes more surgery and the bug had been there
since 2006, so... |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link
mt76_put_vif_phy_link() frees the offchannel mlink with plain kfree()
after rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents
future RCU readers from obtaining the pointer -- it does not wait for
existing readers that already hold it via rcu_dereference.
The TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink->wcid
and mlink->idx under rcu_read_lock. If a TX softirq obtained the pointer
via rcu_dereference just before the NULL assignment, it will dereference
freed memory after the kfree.
struct mt76_vif_link already contains an rcu_head field that is unused at
this free site -- a developer oversight, since the adjacent
kfree_rcu_mightsleep call for rx_sc in the same function shows the
pattern was understood.
Replace kfree(mlink) with kfree_rcu(mlink, rcu_head). |
| In the Linux kernel, the following vulnerability has been resolved:
vhost/net: complete zerocopy ubufs only once
vhost-net initializes one ubuf_info per outstanding zerocopy TX
descriptor and hands it to the backend socket. The networking stack may
then clone a zerocopy skb before all skb references are released. For
example, batman-adv fragmentation reaches skb_split(), which calls
skb_zerocopy_clone() and increments the same ubuf_info refcount.
vhost_zerocopy_complete() currently treats every ubuf callback as a
completed vhost descriptor. It dereferences ubuf->ctx, writes the
descriptor completion state, and drops the vhost_net_ubuf_ref even when
the callback only releases a cloned skb reference. A backend reset can
therefore wait for and free the vhost_net_ubuf_ref while another cloned
skb still carries the same ubuf_info. A later completion then
dereferences the freed ubufs pointer.
KASAN reports the stale completion as:
BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0
BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0
vhost_zerocopy_complete
skb_copy_ubufs
__dev_forward_skb2
veth_xmit
The freed object was allocated from vhost_net_ioctl() while setting the
backend and freed through kfree_rcu()/kvfree_rcu_bulk after backend
removal, while delayed skb completion still reached
vhost_zerocopy_complete().
Honor the generic ubuf_info refcount before touching vhost state, and run
the vhost descriptor completion only for the final ubuf reference. This
matches the msg_zerocopy_complete() ownership rule for cloned zerocopy
skbs. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: fib: Don't dump dying fib_info in fib_leaf_notify().
syzbot reported use-after-free in nsim_fib4_prepare_event(). [0]
The problem is that the following functions call fib_info_hold() /
refcount_inc() while dumping fib_info under RCU, which is unsafe.
* mlxsw_sp_router_fib4_event()
* rocker_router_fib_event()
* nsim_fib4_prepare_event()
refcount_inc_not_zero() must be used, but it would be too late
there.
Let's guarantee the lifetime of fib_info in fib_leaf_notify().
Note that IPv6 does not need the corresponding change since
fib6_table_dump() holds fib6_table.tb6_lock.
[0]:
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#0: kworker/u8:15/3420
Modules linked in:
CPU: 0 UID: 0 PID: 3420 Comm: kworker/u8:15 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: netns cleanup_net
RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25
Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 1b f1 22 fd 48 8d 3d 84 cb f1 0a 67 48 0f b9 3a eb 4a e8 08 f1 22 fd 48 8d 3d 81 cb f1 0a <67> 48 0f b9 3a eb 37 e8 f5 f0 22 fd 48 8d 3d 7e cb f1 0a 67 48 0f
RSP: 0018:ffffc9000f2c7270 EFLAGS: 00010293
RAX: ffffffff84a18858 RBX: 0000000000000002 RCX: ffff888032ff9ec0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8f9353e0
RBP: 0000000000000000 R08: ffff888032ff9ec0 R09: 0000000000000005
R10: 0000000000000100 R11: 0000000000000004 R12: ffff8880570cc000
R13: dffffc0000000000 R14: ffff88802b40563c R15: ffff8880570cc000
FS: 0000000000000000(0000) GS:ffff888126173000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb1f4d5d000 CR3: 000000006072a000 CR4: 00000000003526f0
Call Trace:
<TASK>
__refcount_add include/linux/refcount.h:-1 [inline]
__refcount_inc include/linux/refcount.h:366 [inline]
refcount_inc include/linux/refcount.h:383 [inline]
fib_info_hold include/net/ip_fib.h:629 [inline]
nsim_fib4_prepare_event drivers/net/netdevsim/fib.c:930 [inline]
nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1000 [inline]
nsim_fib_event_nb+0x1055/0x1240 drivers/net/netdevsim/fib.c:1043
call_fib_notifier+0x45/0x80 net/core/fib_notifier.c:25
call_fib_entry_notifier net/ipv4/fib_trie.c:90 [inline]
fib_leaf_notify net/ipv4/fib_trie.c:2176 [inline]
fib_table_notify net/ipv4/fib_trie.c:2194 [inline]
fib_notify+0x36b/0x5e0 net/ipv4/fib_trie.c:2217
fib_net_dump net/core/fib_notifier.c:70 [inline]
register_fib_notifier+0x184/0x360 net/core/fib_notifier.c:108
nsim_fib_create+0x85d/0x9f0 drivers/net/netdevsim/fib.c:1596
nsim_dev_reload_create drivers/net/netdevsim/dev.c:1604 [inline]
nsim_dev_reload_up+0x374/0x7c0 drivers/net/netdevsim/dev.c:1058
devlink_reload+0x501/0x8d0 net/devlink/dev.c:475
devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:558
ops_pre_exit_list net/core/net_namespace.c:161 [inline]
ops_undo_list+0x187/0x940 net/core/net_namespace.c:234
cleanup_net+0x56e/0x800 net/core/net_namespace.c:702
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: fix UAF in tipc_l2_send_msg()
Syzbot reported a slab-use-after-free in ipvlan_hard_header() when
called from tipc_l2_send_msg().
The root cause is that tipc_disable_l2_media() calls synchronize_net()
while b->media_ptr is still valid. This allows concurrent RCU readers
to obtain the device pointer after synchronize_net() has finished.
The pointer is cleared later in bearer_disable(), but without any
subsequent synchronization, allowing the device to be freed while
still in use by readers.
Fix this by clearing b->media_ptr in tipc_disable_l2_media() before
calling synchronize_net().
This is safe to do now because the call order in bearer_disable()
was reversed in 0d051bf93c06 ("tipc: make bearer packet filtering generic")
to call tipc_node_delete_links() (which needs the pointer) before
disable_media().
https: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u |
| In the Linux kernel, the following vulnerability has been resolved:
dmaengine: Fix possible use after free
In dma_release_channel(), check chan->device->privatecnt after call
dma_chan_put(). However, dma_chan_put() call dma_device_put() which could
release the last reference of the device if the DMA provider is already
gone and hence free it.
Fixes it by moving dma_chan_put() after the check. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: ipset: fix order of kfree_rcu() and rcu_assign_pointer()
Sashiko pointed out that kfree_rcu() was called before
rcu_assign_pointer() in handling the comment extension.
Fix the order so that rcu_assign_pointer() called first. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF
The teql master->slaves singly linked list is not protected against
multiple writes. It can be mod'ed concurently from teql_master_xmit(),
teql_dequeue(), teql_init() and teql_destroy() without holding any list
lock or RCU protection.
zdi-disclosures@trendmicro.com has demonstrated that the qdisc is freed
after an RCU grace period, but teql_master_xmit() running on another
CPU can still hold a stale pointer into the list, resulting in a
slab-use-after-free:
BUG: KASAN: slab-use-after-free in teql_master_xmit+0xf0f/0x16b0
Read of size 8 at addr ffff888013fb0440 by task poc/332
Freed 512-byte region [ffff888013fb0400, ffff888013fb0600) (kmalloc-512)
The fix?
Add a per-master slaves_lock spinlock that serializes all mutations of
master->slaves and the NEXT_SLAVE() links in teql_destroy() and
teql_qdisc_init(). teql_master_xmit() also takes the same slaves_lock
around those updates.
Annotate master->slaves and the per-slave ->next pointer with __rcu and
use the appropriate RCU accessors everywhere they are touched:
rcu_assign_pointer() on the writer side (under slaves_lock),
rcu_dereference_protected() for the writer-side loads (also under
slaves_lock), rcu_dereference_bh() for the loads in teql_master_xmit() and
rtnl_dereference() for the loads in teql_master_open()/teql_master_mtu(),
which run under RTNL.
Pair this with rcu_read_lock_bh()/rcu_read_unlock_bh() around the list
traversal in teql_master_xmit(), so that readers either observe a fully
linked list or are deferred until the in-flight mutation completes. The two
early-return paths in teql_master_xmit() are updated to release the RCU-bh
read-side critical section before returning, since leaving it held would
disable BH on that CPU for good. |
| In the Linux kernel, the following vulnerability has been resolved:
bridge: stp: Fix a potential use-after-free when deleting a bridge
The three STP timers are not supposed to be armed while the bridge is
administratively down. They are synchronously deactivated when the
bridge is put administratively down and the various call sites check for
'IFF_UP' before arming them.
This check is missing from br_topology_change_detection() and it is
possible to engineer a situation in which the topology change timer is
armed while the bridge is administratively down, resulting in a
use-after-free [1] when the bridge is deleted.
Fix by adding the missing check and for good measures synchronously
shutdown the three timers when the bridge is deleted.
[1]
ODEBUG: free active (active state 0) object: ffff88811662b9b0 object type: timer_list hint: br_topology_change_timer_expired (net/bridge/br_stp_timer.c:120)
WARNING: lib/debugobjects.c:629 at debug_print_object+0x1bc/0x450, CPU#9: ip/359 |
