| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: x86/mmu: Fix use-after-free on vendor module reload
mmu_destroy_caches() destroys pte_list_desc_cache and
mmu_page_header_cache, but leaves both pointers unchanged. The pointers
live in kvm.ko, and therefore survive when a vendor module is unloaded
while kvm.ko remains loaded.
If creation of pte_list_desc_cache fails during a subsequent vendor
module load, its assignment sets pte_list_desc_cache to NULL and the
error path calls mmu_destroy_caches(). mmu_page_header_cache still
points to the cache destroyed during the preceding vendor module
unload. Passing that stale pointer to kmem_cache_destroy() causes a
slab use-after-free.
Reproduce the issue on a v7.1.3 kernel with CONFIG_KASAN=y,
CONFIG_KASAN_GENERIC=y, CONFIG_KVM=m, and CONFIG_KVM_INTEL=m. A
one-shot test hook forces pte_list_desc_cache to NULL on the second
invocation of kvm_mmu_vendor_module_init():
1. Load kvm.ko and kvm-intel.ko, creating both caches.
2. Unload only kvm_intel, leaving kvm.ko loaded.
3. Reload kvm_intel and force initialization through the -ENOMEM path.
KASAN reports:
BUG: KASAN: slab-use-after-free in
kvm_mmu_vendor_module_init+0x5b/0x170 [kvm]
...
kmem_cache_destroy+0x21/0x1d0
kvm_mmu_vendor_module_init+0x5b/0x170 [kvm]
...
Allocated by task 16817:
__kmem_cache_create_args+0x12c/0x3b0
__kmem_cache_create.constprop.0+0xb6/0xf0 [kvm]
kvm_mmu_vendor_module_init+0x13b/0x170 [kvm]
...
Freed by task 16820:
kmem_cache_destroy+0x117/0x1d0
kvm_mmu_vendor_module_exit+0x21/0x30 [kvm]
Clear both pointers immediately after destroying their caches so that
the stored state reflects the caches' lifetime and repeated cleanup is
safe.
With the fix applied, the same injected vendor module reload fails with
-ENOMEM as expected and produces no KASAN report. |
| In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_tunnel_key: Defer dst_release to RCU callback
Fix a race-condition use-after-free in tunnel_key_release_params().
The function releases the metadata_dst of the old params synchronously
via dst_release() while deferring the params struct free with
kfree_rcu(). A concurrent tunnel_key_act() reader on the datapath may
still hold the old params pointer (under rcu_read_lock_bh) and proceed
to call dst_clone(¶ms->tcft_enc_metadata->dst) after the writer's
dst_release has already pushed the dst's rcuref to RCUREF_DEAD.
zdi-disclosures@trendmicro.com produced a poc which i (and Victor) verified
that KASAN reports:
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112
BUG: KASAN: slab-use-after-free in atomic_sub_return_release include/linux/atomic/atomic-instrumented.h:326
BUG: KASAN: slab-use-after-free in __rcuref_put include/linux/rcuref.h:109
BUG: KASAN: slab-use-after-free in rcuref_put include/linux/rcuref.h:173
BUG: KASAN: slab-use-after-free in dst_release+0x5b/0x370 net/core/dst.c:168
Write of size 4 at addr ffff88806158de40 by task poc/9388
CPU: 0 UID: 0 PID: 9388 Comm: poc Tainted: G W 7.1.0-rc7 #7 PREEMPT(lazy)
Tainted: [W]=WARN
Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378
print_report+0x139/0x4ad mm/kasan/report.c:482
kasan_report+0xe4/0x1d0 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:186
kasan_check_range+0x125/0x200 mm/kasan/generic.c:200
instrument_atomic_read_write include/linux/instrumented.h:112
atomic_sub_return_release include/linux/atomic/atomic-instrumented.h:326
__rcuref_put include/linux/rcuref.h:109
rcuref_put include/linux/rcuref.h:173
dst_release+0x5b/0x370 net/core/dst.c:168
refdst_drop include/net/dst.h:272
skb_dst_drop include/net/dst.h:284
skb_release_head_state+0x293/0x400 net/core/skbuff.c:1163
skb_release_all net/core/skbuff.c:1187
[..]
Allocated by task 9391:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398
__kasan_kmalloc+0x9a/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263
__do_kmalloc_node mm/slub.c:5296
__kmalloc_noprof+0x2f1/0x830 mm/slub.c:5308
kmalloc_noprof include/linux/slab.h:954
kzalloc_noprof include/linux/slab.h:1188
offload_action_alloc+0x2f/0x130 net/core/flow_offload.c:35
tcf_action_offload_add_ex+0x1ba/0x880 net/sched/act_api.c:258
tcf_action_offload_add net/sched/act_api.c:293
tcf_action_init+0x66e/0xa20 net/sched/act_api.c:1547
tcf_action_add+0xf6/0x5d0 net/sched/act_api.c:2101
[..]
Freed by task 9391:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253
__kasan_slab_free+0x6b/0x90 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235
slab_free_hook mm/slub.c:2689
slab_free mm/slub.c:6251
kfree+0x21f/0x6b0 mm/slub.c:6566
tcf_action_offload_add_ex+0x4ad/0x880 net/sched/act_api.c:284
tcf_action_offload_add net/sched/act_api.c:293
tcf_action_init+0x66e/0xa20 net/sched/act_api.c:1547
tcf_action_add+0xf6/0x5d0 net/sched/act_api.c:2101
The buggy address belongs to the object at ffff88806158de00
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 64 bytes inside of
freed 256-byte region [ffff88806158de00, ffff88806158df00)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88806158d600 pfn:0x6158c
head: order:1 mapcount:0 entire_map
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
firmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset calculation
Use the descriptor's `ep_mem_offset` to calculate the start of the endpoint
memory access array and to comply with the FF-A spec instead of defaulting
to `sizeof(struct ffa_mem_region)`.
This requires moving `ffa_mem_region_additional_setup()` earlier in the setup
flow.
Also, add sanity checks to ensure the calculated descriptor offsets do not
exceed `max_fragsize`. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: free AP_VLAN bc_buf SKBs outside IRQ lock
ieee80211_do_stop() removes AP_VLAN packets from the parent AP
ps->bc_buf while holding ps->bc_buf.lock with IRQs disabled. It then
calls ieee80211_free_txskb() before dropping the lock.
ieee80211_free_txskb() is not just a passive SKB release. For SKBs with
TX status state it can report a dropped frame through cfg80211/nl80211,
and that path can reach netlink tap transmit. This is the same reason
the pending queue cleanup in ieee80211_do_stop() already unlinks SKBs
under the queue lock and frees them after IRQ state is restored.
The buggy scenario involves two paths, with each column showing the
order within that path:
AP_VLAN management TX: AP_VLAN stop:
1. attach ACK-status state 1. clear the running state
2. queue a multicast SKB on 2. take ps->bc_buf.lock with IRQs
parent ps->bc_buf disabled
3. unlink the AP_VLAN SKB
4. call ieee80211_free_txskb()
Unlink matching AP_VLAN SKBs from ps->bc_buf under the existing lock,
but move them to a local free queue. Drop the lock and restore IRQ state
before calling ieee80211_free_txskb().
WARNING: kernel/softirq.c:430 at __local_bh_enable_ip |
| In the Linux kernel, the following vulnerability has been resolved:
mtd: virt_concat: fix use-after-free in mtd_virt_concat_destroy_joins()
mtd_concat_destroy() frees item->concat so calling
mtd_virt_concat_put_mtd_devices(item->concat) leads to a use after free.
Fix this by moving mtd_virt_concat_put_mtd_devices() before
mtd_concat_destroy() |
| In the Linux kernel, the following vulnerability has been resolved:
mm/khugepaged: write all dirty file folios when collapsing
[There is no upstream commit, as this code was removed by upstream
commit 044925f9b565 ("mm: fs: remove filemap_nr_thps*() functions and their users")]
As-is, khugepaged and writable-file opening exclude each other. A file
cannot be open writeable and have THPs (because the filesystem is not aware
of them). khugepaged will never collapse file pages for files that are
opened writeable. On an open(O_RDWR/O_WRONLY), the page cache for that
particular file is dropped. This is fine because nothing could've been
dirtied.
However, there is an edge-case: collapse_file() might not be able to
coexist with concurrent writers, but it can coexist with dirty folios
(from previous writers). Therefore, the following can happen:
open(file, O_RDWR)
write(file)
close(file)
madvise(file_mapping, MADV_COLLAPSE, some non-dirty range)
open(file, O_RDWR)
nr_thps > 0
truncate_inode_pages()
/* THPs are cleared out, but so are the dirty folios */
When this edge-case happens, there is data loss, as the dirty folios are
fully discarded.
Fix it by fully writing back the page cache (and waiting) when collapsing
file THPs. Doing so provides the guarantee that no dirty folio will be
observed while there are active THPs. To fully ensure this is safe, the
invalidate_lock needs to be held while doing the writeout, so that
do_dentry_open()'s page cache truncation excludes this write-and-wait.
As a side effect, move the nr_thps counter bumping outside the i_pages
lock. This is correct since the counter itself is an atomic_t and the
producer <-> consumer correctness is provided by a full memory barrier:
smp_mb() in collapse_file()/memory barrier implied by full ordering in
get_write_access() -> atomic_inc_unless_negative(). |
| In the Linux kernel, the following vulnerability has been resolved:
iio: core: fix uninitialized data in debugfs
If *ppos is non-zero then simple_write_to_buffer() will not initialize
the start of buf[]. Non zero values for *ppos aren't going to work
anyway. Test for them at the start of the function and return -EINVAL. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_qca: Clear memdump state on invalid dump size
qca_controller_memdump() allocates qca->qca_memdump before processing
the first dump packet. For a sequence-zero packet it then disables IBS,
marks memdump collection active, and reads the advertised dump size.
If the controller reports a zero dump size, the error path frees the
local qca_memdump object and returns without clearing qca->qca_memdump
or undoing the collection state. A later memdump work item initializes
its local pointer from qca->qca_memdump and skips allocation when that
pointer is non-NULL, so it can operate on freed memory. The stale
collection and IBS-disabled flags can also leave waiters or later
transmit handling blocked behind an aborted dump.
Clear the saved pointer and memdump state before returning from the
invalid-size path, matching the cleanup used when hci_devcd_init() fails.
A static analysis checker reported the stale memdump state, and manual
source review confirmed the invalid-size failure path. |
| In the Linux kernel, the following vulnerability has been resolved:
usb: core: port: Deattach Type-C connector on component unbind
connector_unbind() is the mirror of connector_bind(), but it is missing
the symmetric call to typec_deattach() that connector_bind() makes via:
if (port_dev->child)
typec_attach(port_dev->connector, &port_dev->child->dev);
When a Thunderbolt dock is unplugged, two teardown paths race:
1. The component framework calls connector_unbind() first, which sets
port_dev->connector = NULL without calling typec_deattach(). This
leaves port->usb2_dev/port->usb3_dev in struct typec_port pointing at
the USB device that is about to be freed.
2. usb_disconnect() then calls typec_deattach(port_dev->connector, ...),
but port_dev->connector is already NULL, so the call is a no-op and
port->usb2_dev is never cleared.
3. Concurrently, UCSI detects a PD partner-disconnect event and calls
typec_unregister_partner(), which reads port->usb2_dev (now a dangling
pointer to freed memory) and passes it to typec_partner_unlink_device()
-> sysfs_remove_link() -> dev_name() on the freed device, corrupting
the typec/UCSI partner state.
This corruption leaves the Thunderbolt tunnel in an inconsistent state on
the next dock hot-plug. On affected hardware the dock's I225/igc NIC fails
to enumerate: AER fires a slot reset while the igc driver is still
initialising ("PCIe link lost"), and the subsequent igc_reset attempt hits
igc_rd32 on an already-detached device:
igc 0000:2e:00.0 eth0: PCIe link lost, device now detached
igc: Failed to read reg 0x0!
WARNING: CPU: 9 PID: 129 at drivers/net/ethernet/intel/igc/igc_main.c:7005
igc_rd32+0xa4/0xc0 [igc]
Call Trace:
igc_disable_pcie_master+0x16/0xa0 [igc]
igc_reset_hw_base+0x14/0x170 [igc]
igc_reset+0x63/0x110 [igc]
igc_io_slot_reset+0x9e/0xd0 [igc]
report_slot_reset+0x5d/0xc0
pcie_do_recovery+0x209/0x400
aer_isr_one_error_type+0x235/0x430
aer_isr+0x4e/0x80
irq_thread+0xf4/0x1f0
4. UCSI later handles the PD partner-disconnect and calls
typec_unregister_partner(), which still sees the stale port->usb2_dev
and tries to remove its sysfs link a second time:
kernfs: can not remove 'typec', no directory
WARNING: CPU: 6 PID: 55 at fs/kernfs/dir.c:1706 kernfs_remove_by_name_ns+0xe9/0xf0
Workqueue: events ucsi_handle_connector_change [typec_ucsi]
Call Trace:
sysfs_remove_link+0x19/0x50
typec_unregister_partner+0x6e/0x120 [typec]
ucsi_unregister_partner+0x107/0x150 [typec_ucsi]
ucsi_handle_connector_change+0x3ec/0x490 [typec_ucsi]
process_one_work+0x18e/0x3e0
worker_thread+0x2e3/0x420
kthread+0x10a/0x230
ret_from_fork+0x121/0x140
ret_from_fork_asm+0x1a/0x30
With worse timing the same stale pointer is dereferenced after the
backing memory is freed, turning the warning into a use-after-free.
Fix the asymmetry: call typec_deattach() before clearing
port_dev->connector, matching what connector_bind() does on the bind side.
typec_partner_deattach() is already protected by port->partner_link_lock,
so it serialises safely with the concurrent typec_unregister_partner() path. |
| In the Linux kernel, the following vulnerability has been resolved:
net/iucv: take a reference on the socket found in afiucv_hs_rcv()
afiucv_hs_rcv() looks up the destination socket under iucv_sk_list.lock,
drops the lock, and then passes the socket to the afiucv_hs_callback_*()
handlers without holding a reference. AF_IUCV sockets are not
RCU-protected and are freed synchronously by iucv_sock_kill() ->
sock_put(), so a concurrent close can free the socket in the window
between read_unlock() and the handler, which then dereferences freed
memory (for example sk->sk_data_ready() in afiucv_hs_callback_syn()).
Take a reference with sock_hold() while the socket is still on the list
and release it with sock_put() once the handler has run. |
| In the Linux kernel, the following vulnerability has been resolved:
gpu: host1x: Fix use-after-free in host1x_bo_clear_cached_mappings
__host1x_bo_unpin() drops the last reference to the mapping and frees
it, so we can't dereference mapping afterwards. The cache itself
outlives the mapping, so use the cache local variable instead. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/xe/guc: Keep scheduler timeline name alive
The scheduler keeps a pointer to the timeline name, but q->name
is freed with the exec queue while scheduler fences can still
reference it.
Store the name in struct xe_guc_exec_queue so it shares
the scheduler's RCU-deferred lifetime.
(cherry picked from commit 41075f0eb5dcbd3b065d15f15ef7bbe9315188e8) |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: defer link RX stats percpu free to RCU
sta_remove_link() frees a removed MLO link's RX stats percpu buffer right
away, but defers only the link container to RCU:
sta_info_free_link(&alloc->info);
kfree_rcu(alloc, rcu_head);
The RX fast path reads link_sta under rcu_read_lock and writes the percpu
stats. A reader that resolved link_sta before the removal keeps the
pointer. The container stays alive from the kfree_rcu, so the read still
works. But the percpu block it points to is already freed. This needs
uses_rss. That is when pcpu_rx_stats exists.
The full STA teardown frees the deflink stats only after
synchronize_net(). The link removal path had no such barrier. The race is
hard to win in practice, but the free should still wait for RCU.
Free the link together with its data from a single RCU callback, so the
percpu block is reclaimed only after readers drain. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: cancel sched scan results work on unregister
cfg80211_sched_scan_results() can queue rdev->sched_scan_res_wk from a
driver result notification while a scheduled scan request is present. The
work callback recovers the containing cfg80211_registered_device and then
locks the wiphy and walks the scheduled-scan request list.
wiphy_unregister() already makes the wiphy unreachable and drains rdev work
items before cfg80211_dev_free() can release the object, but it does not
drain sched_scan_res_wk. A queued or running result work item can therefore
cross the unregister/free boundary and access freed rdev state.
The buggy scenario involves two paths, with each column showing the order
within that path:
scheduled-scan result path: unregister/free path:
1. cfg80211_sched_scan_results() 1. interface teardown stops and
queues rdev->sched_scan_res_wk. removes the scheduled scan request.
2. cfg80211_wq starts the work 2. wiphy_unregister() drains other
item and recovers rdev. rdev work items.
3. The worker locks rdev->wiphy 3. cfg80211_dev_free() destroys and
and walks rdev state. frees rdev.
Cancel sched_scan_res_wk in wiphy_unregister() alongside the other rdev
work items. cancel_work_sync() removes a pending result notification and
waits for an already running callback, so cfg80211_dev_free() cannot free
rdev while this work item is still active.
Validation reproduced this kernel report:
BUG: KASAN: use-after-free in cfg80211_sched_scan_results_wk+0x4a6/0x530
Workqueue: cfg80211 cfg80211_sched_scan_results_wk [cfg80211]
Read of size 8
Call trace:
dump_stack_lvl+0x66/0xa0
print_report+0xce/0x630
cfg80211_sched_scan_results_wk+0x4a6/0x530
srso_alias_return_thunk+0x5/0xfbef5
__virt_addr_valid+0x224/0x430
kasan_report+0xac/0xe0
lockdep_hardirqs_on_prepare+0xea/0x1a0
process_one_work+0x8d0/0x18f0 (kernel/workqueue.c:3212)
lock_is_held_type+0x8f/0x100
worker_thread+0x5ad/0xfd0
__kthread_parkme+0xc6/0x200
kthread+0x31e/0x410
trace_hardirqs_on+0x1a/0x170
ret_from_fork+0x576/0x810
__switch_to+0x57e/0xe20
__switch_to_asm+0x33/0x70
ret_from_fork_asm+0x1a/0x30 |
| In the Linux kernel, the following vulnerability has been resolved:
xfrm: clear mode callbacks after failed mode setup
xfrm_state_gc_task can run long after a failed IPTFS state setup. In the
reproduced case, __xfrm_init_state() cached x->mode_cbs, IPTFS setup
returned -ENOMEM before publishing mode_data, and the temporary module
reference from xfrm_get_mode_cbs() was dropped immediately. The dead state
then kept x->mode_cbs until deferred GC ran after xfrm_iptfs had been
unloaded.
Clear x->mode_cbs when mode init or clone fails before publishing
mode_data. Those states never installed mode-specific state or the
long-term IPTFS module pin, so deferred GC has nothing mode-specific to
destroy and must not retain a callback table pointer past the temporary
lookup reference.
The buggy scenario involves two paths, with each column showing the order
within that path:
failed setup path:
1. cache x->mode_cbs
2. mode setup fails before mode_data
3. drop the temporary module ref
4. dead state keeps x->mode_cbs cached
GC/unload path:
1. xfrm_state_put() queues GC work
2. xfrm_iptfs unloads later
3. xfrm_state_gc_task runs
4. GC dereferences stale x->mode_cbs
This also covers the failed clone path where clone_state() returns before
publishing mode_data.
Validation reproduced this kernel report:
Kernel panic - not syncing: Fatal exception
CONFIG_FAULT_INJECTION_STACKTRACE_FILTER=y
failslab_stacktrace_filter matched xfrm_iptfs frames
ack_error=-12
FAULT_INJECTION: forcing a failure
BUG: unable to handle page fault
Workqueue: events xfrm_state_gc_task
RIP: xfrm_state_gc_task+0x142/0x650
Modules linked in: esp4_offload xfrm_user [last unloaded: xfrm_iptfs]
Kernel panic - not syncing: Fatal exception |
| In the Linux kernel, the following vulnerability has been resolved:
hwmon: (corsair-cpro) Stop device IO before calling hid_hw_stop
Calling hid_hw_stop() does not stop the device IO.
This results in a race condition between hid_input_report() and the point
immediately following the execution of hid_device_io_start() within
the driver probe function. If the probe operation fails after "io start"
has been initiated, this race condition will result in a UAF vulnerability.
Fix the problem by calling hid_device_io_stop() before calling
hid_hw_stop(). |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix UAF in sock clone early bailouts
Similar to recent commit 9b51a6155d14 ("bpf,fork: wipe ->bpf_storage
before bailouts that access it"), sk_clone() performs an initial
shallow copy of the socket field ->sk_bpf_storage via sock_copy()
for the cloned socket newsk.
If sk_clone() bails out early (e.g. if sk_filter_charge() fails) prior
to calling bpf_sk_storage_clone(), newsk->sk_bpf_storage still points
to the parent socket's BPF local storage. When newsk is subsequently
freed via sk_free(), the deallocation path (__sk_destruct() ->
bpf_sk_storage_free()) destroys the parent socket's BPF local storage,
leading to a use-after-free (UAF) on the parent socket.
Fix this by resetting newsk->sk_bpf_storage to NULL immediately after
sock_copy() in sk_clone(), and remove the now redundant initialization
from bpf_sk_storage_clone(). |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: initialize SDIO data work before cleanup
brcmf_sdio_probe() stores the newly allocated bus in sdiodev->bus before
allocating the ordered workqueue. If that allocation fails, the function
jumps to fail and calls brcmf_sdio_remove().
brcmf_sdio_remove() unconditionally cancels bus->datawork. Initialize the
work item before the first failure path that can reach brcmf_sdio_remove(),
so the cleanup path always observes a valid work object.
This issue was found by our static analysis tool and then confirmed by
manual review of the probe error path and the remove-time work drain. The
problem pattern is an early setup failure that reaches a cleanup helper
which cancels an embedded work item before its initializer has run.
A QEMU PoC forced alloc_ordered_workqueue() to fail at the same point in
brcmf_sdio_probe(), before INIT_WORK(&bus->datawork) is reached. The
resulting fail path calls brcmf_sdio_remove(), and DEBUG_OBJECTS reports
the invalid work drain with brcmf_sdio_probe() and brcmf_sdio_remove() in
the stack. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update
MGMT_OP_LOAD_CONN_PARAM queues conn_update_sync() when a single parameter
update changes an existing LE central connection. The queued work currently
stores a borrowed hci_conn_params entry from hdev->le_conn_params. A later
LOAD_CONN_PARAM request can clear disabled parameters and free that entry
before hci_cmd_sync_work() runs the queued callback.
Do not keep the borrowed hci_conn_params pointer in queued work. Queue the
hci_conn instead and hold a reference until the queued callback completes.
When the work runs, revalidate that the connection is still present, look
up the current hci_conn_params entry, and cancel the update if userspace
removed that entry while the work was pending.
Copy the interval values from the current params entry under hdev->lock,
then drop the lock and keep using hci_le_conn_update_sync() to issue the
update.
Validation reproduced this kernel report:
BUG: KASAN: slab-use-after-free in conn_update_sync+0x2a/0xf0 [bluetooth]
Read of size 1 at addr ffff88810c697126 by task kworker/u17:0/377
Workqueue: hci0 hci_cmd_sync_work [bluetooth]
Call Trace:
<TASK>
dump_stack_lvl+0x66/0xa0
print_report+0xce/0x5f0
kasan_report+0xe0/0x110
conn_update_sync+0x2a/0xf0 [bluetooth]
hci_cmd_sync_work+0x187/0x210 [bluetooth]
process_one_work+0x4fd/0xbc0
worker_thread+0x2d8/0x570
kthread+0x1ad/0x1f0
ret_from_fork+0x3c9/0x540
ret_from_fork_asm+0x1a/0x30
Allocated by task 466:
hci_conn_params_add+0xa6/0x240 [bluetooth]
load_conn_param+0x4e1/0x850 [bluetooth]
hci_sock_sendmsg+0x96b/0xf80 [bluetooth]
Freed by task 474:
kfree+0x313/0x590
hci_conn_params_clear_disabled+0x9b/0xc0 [bluetooth]
load_conn_param+0x4bf/0x850 [bluetooth]
hci_sock_sendmsg+0x96b/0xf80 [bluetooth] |
| In the Linux kernel, the following vulnerability has been resolved:
ppp: defer channel free to an RCU grace period to fix pppol2tp RX UAF
pppol2tp_recv() runs in the L2TP UDP-encap softirq RX path:
l2tp_udp_encap_recv() -> l2tp_recv_common() -> pppol2tp_recv()
-> ppp_input(&po->chan)
It runs under rcu_read_lock() holding only an l2tp_session reference and
takes NO reference on the internal PPP channel (struct channel,
chan->ppp) that ppp_input() dereferences.
The pppox socket is SOCK_RCU_FREE, so 'po' and the embedded ppp_channel
are RCU-safe. But the internal struct channel is a separate allocation
that ppp_release_channel() frees with a plain kfree():
close(data socket) -> pppol2tp_release() -> pppox_unbind_sock()
-> ppp_unregister_channel() -> ppp_release_channel() -> kfree(pch)
For a channel that is bound (PPPIOCGCHAN) but not attached to a ppp unit
(no PPPIOCCONNECT, pch->ppp == NULL) and not bridged, teardown skips
both ppp_disconnect_channel()'s synchronize_net() and
ppp_unbridge_channels()'s synchronize_rcu(), so the kfree() has no grace
period. rcu_read_lock() in pppol2tp_recv() does not protect against a
plain kfree(), so an in-flight ppp_input() on one CPU can dereference
the channel just freed by close() on another CPU.
The bug is reachable by an unprivileged user.
Defer the channel free to an RCU callback via call_rcu() so the grace
period fences any in-flight ppp_input(). The disconnect and unbridge
teardown paths already fence with synchronize_net()/synchronize_rcu();
call_rcu() does the same here without stalling the close() path. |
