Cen Zhang 0bfeec2198 usb: misc: usbio: fix disconnect UAF in client teardown
usbio_disconnect() walks usbio->cli_list in reverse and uninitializes each
auxiliary device. auxiliary_device_uninit() drops the device reference, and
for an unbound child that can run usbio_auxdev_release() and free the
containing struct usbio_client.

list_for_each_entry_reverse() advances after the loop body by reading
client->link.prev. If the current client is freed by
auxiliary_device_uninit(), the iterator dereferences freed memory.

Use list_for_each_entry_safe_reverse() so the previous client is
cached before the body can drop the final reference. This preserves
reverse teardown order while keeping the next iterator cursor independent
of the current client's lifetime.

Validation reproduced this kernel report:
BUG: KASAN: slab-use-after-free in usbio_disconnect+0x12e/0x150

Call Trace:
 <TASK>
 dump_stack_lvl+0x66/0xa0
 print_report+0xce/0x630
 ? usbio_disconnect+0x12e/0x150
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? __virt_addr_valid+0x188/0x320
 ? usbio_disconnect+0x12e/0x150
 kasan_report+0xe0/0x110
 ? usbio_disconnect+0x12e/0x150
 usbio_disconnect+0x12e/0x150
 usb_unbind_interface+0xf3/0x400
 really_probe+0x316/0x660
 __driver_probe_device+0x106/0x240
 driver_probe_device+0x4a/0x110
 __device_attach_driver+0xf1/0x1a0
 ? __pfx___device_attach_driver+0x10/0x10
 bus_for_each_drv+0xf9/0x160
 ? __pfx_bus_for_each_drv+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? trace_hardirqs_on+0x18/0x130
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? _raw_spin_unlock_irqrestore+0x44/0x60
 __device_attach+0x133/0x2a0
 ? __pfx___device_attach+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? do_raw_spin_unlock+0x9a/0x100
 ? srso_alias_return_thunk+0x5/0xfbef5
 device_initial_probe+0x55/0x70
 bus_probe_device+0x4a/0xd0
 device_add+0x9b9/0xc10
 ? __pfx_device_add+0x10/0x10
 ? _raw_spin_unlock_irqrestore+0x44/0x60
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? lockdep_hardirqs_on_prepare+0xea/0x1a0
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? usb_enable_lpm+0x3c/0x260
 usb_set_configuration+0xb64/0xf20
 usb_generic_driver_probe+0x5f/0x90
 usb_probe_device+0x71/0x1b0
 really_probe+0x46b/0x660
 __driver_probe_device+0x106/0x240
 driver_probe_device+0x4a/0x110
 __device_attach_driver+0xf1/0x1a0
 ? __pfx___device_attach_driver+0x10/0x10
 bus_for_each_drv+0xf9/0x160
 ? __pfx_bus_for_each_drv+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? trace_hardirqs_on+0x18/0x130
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? _raw_spin_unlock_irqrestore+0x44/0x60
 __device_attach+0x133/0x2a0
 ? __pfx___device_attach+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? do_raw_spin_unlock+0x9a/0x100
 ? srso_alias_return_thunk+0x5/0xfbef5
 device_initial_probe+0x55/0x70
 bus_probe_device+0x4a/0xd0
 device_add+0x9b9/0xc10
 ? __pfx_device_add+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? add_device_randomness+0xb7/0xf0
 usb_new_device+0x492/0x870
 hub_event+0x1b10/0x29c0
 ? __pfx_hub_event+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? lock_acquire+0x187/0x300
 ? process_one_work+0x475/0xb90
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? lock_release+0xc8/0x290
 ? srso_alias_return_thunk+0x5/0xfbef5
 process_one_work+0x4d7/0xb90
 ? __pfx_process_one_work+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? __list_add_valid_or_report+0x37/0xf0
 ? __pfx_hub_event+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 worker_thread+0x2d8/0x570
 ? __pfx_worker_thread+0x10/0x10
 kthread+0x1ad/0x1f0
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x3c9/0x540
 ? __pfx_ret_from_fork+0x10/0x10
 ? srso_alias_return_thunk+0x5/0xfbef5
 ? __switch_to+0x2e9/0x730
 ? __pfx_kthread+0x10/0x10
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Fixes: 121a0f839d ("usb: misc: Add Intel USBIO bridge driver")
Cc: stable <stable@kernel.org>
Assisted-by: Codex:gpt-5.5
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
Reviewed-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Link: https://patch.msgid.link/20260618124029.3704089-1-zzzccc427@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-08 17:17:29 +02:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
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Essential Documentation
-----------------------

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* Building requirements: Documentation/process/changes.rst
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* License: See COPYING

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============

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For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
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* Coding Style: Documentation/process/coding-style.rst
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* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
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---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
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Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

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--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
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* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
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Hardware Vendor
---------------

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* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


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=========================

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