AZL-99486

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_sync: Fix accept list UAF during suspend

hciupdateeventfiltersync() walks hdev->acceptlist while sending a synchronous HCI command for each remote-wakeup device. The suspend path holds hdev->reqlock, but accept-list updates are serialized by hdev->lock. Consequently, remove_device() can free the current list entry during the controller wait.

The following interleaving causes the use-after-free:

hciupdateeventfiltersync() removedevice() fetch accept-list entry hciseteventfiltersync() wait for controller response hcidevlock() listdel() kfree() hcidevunlock() read the freed list.next

KASAN reported:

BUG: KASAN: slab-use-after-free in hcisuspendsync+0x835/0x910 Read of size 8 at addr ffff88810bec8440 by task kworker/0:1/10 Workqueue: events vhcisuspendwork Call Trace: hcisuspendsync+0x835/0x910 hcisuspenddev+0x182/0x450 processonework+0x661/0x1090 worker_thread+0x45b/0xd10

Allocated by task 86: hcibdaddrlistaddwithflags+0x1a8/0x400 adddevice+0x381/0x820 hcisocksendmsg+0x1033/0x1ea0

Freed by task 91: kfree+0x131/0x3c0 removedevice+0x429/0xb70 hcisock_sendmsg+0x1033/0x1ea0

Snapshot the remote-wakeup addresses under hdev->lock. Release the lock before sending HCI commands. Clear the controller event filter before building the snapshot, and skip allocation and the second list traversal when there are no matching entries. This preserves the original filter and scan-state updates without retaining an accept-list node across a controller wait.