CVE-2025-22020

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

memstick: rtsx_usb_ms: Fix slab-use-after-free in rtsx_usb_ms_drv_remove

This fixes the following crash:

================================================================== BUG: KASAN: slab-use-after-free in rtsx_usb_ms_poll_card+0x159/0x200 [rtsx_usb_ms] Read of size 8 at addr ffff888136335380 by task kworker/6:0/140241

CPU: 6 UID: 0 PID: 140241 Comm: kworker/6:0 Kdump: loaded Tainted: G E 6.14.0-rc6+ #1 Tainted: [E]=UNSIGNED_MODULE Hardware name: LENOVO 30FNA1V7CW/1057, BIOS S0EKT54A 07/01/2024 Workqueue: events rtsx_usb_ms_poll_card [rtsx_usb_ms] Call Trace: <TASK> dump_stack_lvl+0x51/0x70 print_address_description.constprop.0+0x27/0x320 ? rtsx_usb_ms_poll_card+0x159/0x200 [rtsx_usb_ms] print_report+0x3e/0x70 kasan_report+0xab/0xe0 ? rtsx_usb_ms_poll_card+0x159/0x200 [rtsx_usb_ms] rtsx_usb_ms_poll_card+0x159/0x200 [rtsx_usb_ms] ? __pfx_rtsx_usb_ms_poll_card+0x10/0x10 [rtsx_usb_ms] ? __pfx___schedule+0x10/0x10 ? kick_pool+0x3b/0x270 process_one_work+0x357/0x660 worker_thread+0x390/0x4c0 ? __pfx_worker_thread+0x10/0x10 kthread+0x190/0x1d0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2d/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK>

Allocated by task 161446: kasan_save_stack+0x20/0x40 kasan_save_track+0x10/0x30 __kasan_kmalloc+0x7b/0x90 __kmalloc_noprof+0x1a7/0x470 memstick_alloc_host+0x1f/0xe0 [memstick] rtsx_usb_ms_drv_probe+0x47/0x320 [rtsx_usb_ms] platform_probe+0x60/0xe0 call_driver_probe+0x35/0x120 really_probe+0x123/0x410 __driver_probe_device+0xc7/0x1e0 driver_probe_device+0x49/0xf0 __device_attach_driver+0xc6/0x160 bus_for_each_drv+0xe4/0x160 __device_attach+0x13a/0x2b0 bus_probe_device+0xbd/0xd0 device_add+0x4a5/0x760 platform_device_add+0x189/0x370 mfd_add_device+0x587/0x5e0 mfd_add_devices+0xb1/0x130 rtsx_usb_probe+0x28e/0x2e0 [rtsx_usb] usb_probe_interface+0x15c/0x460 call_driver_probe+0x35/0x120 really_probe+0x123/0x410 __driver_probe_device+0xc7/0x1e0 driver_probe_device+0x49/0xf0 __device_attach_driver+0xc6/0x160 bus_for_each_drv+0xe4/0x160 __device_attach+0x13a/0x2b0 rebind_marked_interfaces.isra.0+0xcc/0x110 usb_reset_device+0x352/0x410 usbdev_do_ioctl+0xe5c/0x1860 usbdev_ioctl+0xa/0x20 __x64_sys_ioctl+0xc5/0xf0 do_syscall_64+0x59/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Freed by task 161506: kasan_save_stack+0x20/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x36/0x60 __kasan_slab_free+0x34/0x50 kfree+0x1fd/0x3b0 device_release+0x56/0xf0 kobject_cleanup+0x73/0x1c0 rtsx_usb_ms_drv_remove+0x13d/0x220 [rtsx_usb_ms] platform_remove+0x2f/0x50 device_release_driver_internal+0x24b/0x2e0 bus_remove_device+0x124/0x1d0 device_del+0x239/0x530 platform_device_del.part.0+0x19/0xe0 platform_device_unregister+0x1c/0x40 mfd_remove_devices_fn+0x167/0x170 device_for_each_child_reverse+0xc9/0x130 mfd_remove_devices+0x6e/0xa0 rtsx_usb_disconnect+0x2e/0xd0 [rtsx_usb] usb_unbind_interface+0xf3/0x3f0 device_release_driver_internal+0x24b/0x2e0 proc_disconnect_claim+0x13d/0x220 usbdev_do_ioctl+0xb5e/0x1860 usbdev_ioctl+0xa/0x20 __x64_sys_ioctl+0xc5/0xf0 do_syscall_64+0x59/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Last potentially related work creation: kasan_save_stack+0x20/0x40 kasan_record_aux_stack+0x85/0x90 insert_work+0x29/0x100 __queue_work+0x34a/0x540 call_timer_fn+0x2a/0x160 expire_timers+0x5f/0x1f0 __run_timer_base.part.0+0x1b6/0x1e0 run_timer_softirq+0x8b/0xe0 handle_softirqs+0xf9/0x360 __irq_exit_rcu+0x114/0x130 sysvec_apic_timer_interrupt+0x72/0x90 asm_sysvec_apic_timer_interrupt+0x16/0x20

Second to last potentially related work creation: kasan_save_stack+0x20/0x40 kasan_record_aux_stack+0x85/0x90 insert_work+0x29/0x100 __queue_work+0x34a/0x540 call_timer_fn+0x2a/0x160 expire_timers+0x5f/0x1f0 __run_timer_base.part.0+0x1b6/0x1e0 run_timer_softirq+0x8b/0xe0 handle_softirqs+0xf9/0x ---truncated---

This vulnerability is caused by a race condition between the driver removal routine and a periodically scheduled work function (poll_card). It can be triggered by attaching and then removing a USB device, which in turn calls the removal subroutine, which runs before ensuring that the poll_card work item is canceled.

If done physically, then the attack requires no particular user privileges. However, implementing a programmatic version of this vulnerability would require elevated privileges (e.g. CAP_SYS_ADMIN) as it would require driver unbinding and/or device removal.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.