In the Linux kernel, the following vulnerability has been resolved: usb: typec: ucsi: fix use-after-free caused by uec->work The delayed work uec->work is scheduled in gaokun_ucsi_probe() but never properly canceled in gaokun_ucsi_remove(). This creates use-after-free scenarios where the ucsi and gaokun_ucsi structure are freed after ucsi_destroy() completes execution, while the gaokun_ucsi_register_worker() might be either currently executing or still pending in the work queue. The already-freed gaokun_ucsi or ucsi structure may then be accessed. Furthermore, the race window is 3 seconds, which is sufficiently long to make this bug easily reproducible. The following is the trace captured by KASAN: ================================================================== BUG: KASAN: slab-use-after-free in __run_timers+0x5ec/0x630 Write of size 8 at addr ffff00000ec28cc8 by task swapper/0/0 ... Call trace: show_stack+0x18/0x24 (C) dump_stack_lvl+0x78/0x90 print_report+0x114/0x580 kasan_report+0xa4/0xf0 __asan_report_store8_noabort+0x20/0x2c __run_timers+0x5ec/0x630 run_timer_softirq+0xe8/0x1cc handle_softirqs+0x294/0x720 __do_softirq+0x14/0x20 ____do_softirq+0x10/0x1c call_on_irq_stack+0x30/0x48 do_softirq_own_stack+0x1c/0x28 __irq_exit_rcu+0x27c/0x364 irq_exit_rcu+0x10/0x1c el1_interrupt+0x40/0x60 el1h_64_irq_handler+0x18/0x24 el1h_64_irq+0x6c/0x70 arch_local_irq_enable+0x4/0x8 (P) do_idle+0x334/0x458 cpu_startup_entry+0x60/0x70 rest_init+0x158/0x174 start_kernel+0x2f8/0x394 __primary_switched+0x8c/0x94 Allocated by task 72 on cpu 0 at 27.510341s: kasan_save_stack+0x2c/0x54 kasan_save_track+0x24/0x5c kasan_save_alloc_info+0x40/0x54 __kasan_kmalloc+0xa0/0xb8 __kmalloc_node_track_caller_noprof+0x1c0/0x588 devm_kmalloc+0x7c/0x1c8 gaokun_ucsi_probe+0xa0/0x840 auxiliary_bus_probe+0x94/0xf8 really_probe+0x17c/0x5b8 __driver_probe_device+0x158/0x2c4 driver_probe_device+0x10c/0x264 __device_attach_driver+0x168/0x2d0 bus_for_each_drv+0x100/0x188 __device_attach+0x174/0x368 device_initial_probe+0x14/0x20 bus_probe_device+0x120/0x150 device_add+0xb3c/0x10fc __auxiliary_device_add+0x88/0x130 ... Freed by task 73 on cpu 1 at 28.910627s: kasan_save_stack+0x2c/0x54 kasan_save_track+0x24/0x5c __kasan_save_free_info+0x4c/0x74 __kasan_slab_free+0x60/0x8c kfree+0xd4/0x410 devres_release_all+0x140/0x1f0 device_unbind_cleanup+0x20/0x190 device_release_driver_internal+0x344/0x460 device_release_driver+0x18/0x24 bus_remove_device+0x198/0x274 device_del+0x310/0xa84 ... The buggy address belongs to the object at ffff00000ec28c00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 200 bytes inside of freed 512-byte region The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4ec28 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x3fffe0000000040(head|node=0|zone=0|lastcpupid=0x1ffff) page_type: f5(slab) raw: 03fffe0000000040 ffff000008801c80 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000 head: 03fffe0000000040 ffff000008801c80 dead000000000122 0000000000000000 head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000 head: 03fffe0000000002 fffffdffc03b0a01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff00000ec28b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff00000ec28c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff00000ec28c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff00000ec28d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff00000ec28d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================ ---truncated---
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