CVE-2024-50150

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

usb: typec: altmode should keep reference to parent

The altmode device release refers to its parent device, but without keeping

a reference to it.

When registering the altmode, get a reference to the parent and put it in

the release function.

Before this fix, when using CONFIG_DEBUG_KOBJECT_RELEASE, we see issues

like this:

[ 43.572860] kobject: 'port0.0' (ffff8880057ba008): kobject_release, parent 0000000000000000 (delayed 3000)

[ 43.573532] kobject: 'port0.1' (ffff8880057bd008): kobject_release, parent 0000000000000000 (delayed 1000)

[ 43.574407] kobject: 'port0' (ffff8880057b9008): kobject_release, parent 0000000000000000 (delayed 3000)

[ 43.575059] kobject: 'port1.0' (ffff8880057ca008): kobject_release, parent 0000000000000000 (delayed 4000)

[ 43.575908] kobject: 'port1.1' (ffff8880057c9008): kobject_release, parent 0000000000000000 (delayed 4000)

[ 43.576908] kobject: 'typec' (ffff8880062dbc00): kobject_release, parent 0000000000000000 (delayed 4000)

[ 43.577769] kobject: 'port1' (ffff8880057bf008): kobject_release, parent 0000000000000000 (delayed 3000)

[ 46.612867] ==================================================================

[ 46.613402] BUG: KASAN: slab-use-after-free in typec_altmode_release+0x38/0x129

[ 46.614003] Read of size 8 at addr ffff8880057b9118 by task kworker/2:1/48

[ 46.614538]

[ 46.614668] CPU: 2 UID: 0 PID: 48 Comm: kworker/2:1 Not tainted 6.12.0-rc1-00138-gedbae730ad31 #535

[ 46.615391] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014

[ 46.616042] Workqueue: events kobject_delayed_cleanup

[ 46.616446] Call Trace:

[ 46.616648] <TASK>

[ 46.616820] dump_stack_lvl+0x5b/0x7c

[ 46.617112] ? typec_altmode_release+0x38/0x129

[ 46.617470] print_report+0x14c/0x49e

[ 46.617769] ? rcu_read_unlock_sched+0x56/0x69

[ 46.618117] ? __virt_addr_valid+0x19a/0x1ab

[ 46.618456] ? kmem_cache_debug_flags+0xc/0x1d

[ 46.618807] ? typec_altmode_release+0x38/0x129

[ 46.619161] kasan_report+0x8d/0xb4

[ 46.619447] ? typec_altmode_release+0x38/0x129

[ 46.619809] ? process_scheduled_works+0x3cb/0x85f

[ 46.620185] typec_altmode_release+0x38/0x129

[ 46.620537] ? process_scheduled_works+0x3cb/0x85f

[ 46.620907] device_release+0xaf/0xf2

[ 46.621206] kobject_delayed_cleanup+0x13b/0x17a

[ 46.621584] process_scheduled_works+0x4f6/0x85f

[ 46.621955] ? __pfx_process_scheduled_works+0x10/0x10

[ 46.622353] ? hlock_class+0x31/0x9a

[ 46.622647] ? lock_acquired+0x361/0x3c3

[ 46.622956] ? move_linked_works+0x46/0x7d

[ 46.623277] worker_thread+0x1ce/0x291

[ 46.623582] ? __kthread_parkme+0xc8/0xdf

[ 46.623900] ? __pfx_worker_thread+0x10/0x10

[ 46.624236] kthread+0x17e/0x190

[ 46.624501] ? kthread+0xfb/0x190

[ 46.624756] ? __pfx_kthread+0x10/0x10

[ 46.625015] ret_from_fork+0x20/0x40

[ 46.625268] ? __pfx_kthread+0x10/0x10

[ 46.625532] ret_from_fork_asm+0x1a/0x30

[ 46.625805] </TASK>

[ 46.625953]

[ 46.626056] Allocated by task 678:

[ 46.626287] kasan_save_stack+0x24/0x44

[ 46.626555] kasan_save_track+0x14/0x2d

[ 46.626811] __kasan_kmalloc+0x3f/0x4d

[ 46.627049] __kmalloc_noprof+0x1bf/0x1f0

[ 46.627362] typec_register_port+0x23/0x491

[ 46.627698] cros_typec_probe+0x634/0xbb6

[ 46.628026] platform_probe+0x47/0x8c

[ 46.628311] really_probe+0x20a/0x47d

[ 46.628605] device_driver_attach+0x39/0x72

[ 46.628940] bind_store+0x87/0xd7

[ 46.629213] kernfs_fop_write_iter+0x1aa/0x218

[ 46.629574] vfs_write+0x1d6/0x29b

[ 46.629856] ksys_write+0xcd/0x13b

[ 46.630128] do_syscall_64+0xd4/0x139

[ 46.630420] entry_SYSCALL_64_after_hwframe+0x76/0x7e

[ 46.630820]

[ 46.630946] Freed by task 48:

[ 46.631182] kasan_save_stack+0x24/0x44

[ 46.631493] kasan_save_track+0x14/0x2d

[ 46.631799] kasan_save_free_info+0x3f/0x4d

[ 46.632144] __kasan_slab_free+0x37/0x45

[ 46.632474]

---truncated---