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Message-ID: <2025072509-CVE-2025-38394-f005@gregkh>
Date: Fri, 25 Jul 2025 14:55:25 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38394: HID: appletb-kbd: fix memory corruption of input_handler_list
From: Greg Kroah-Hartman <gregkh@...nel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
HID: appletb-kbd: fix memory corruption of input_handler_list
In appletb_kbd_probe an input handler is initialised and then registered
with input core through input_register_handler(). When this happens input
core will add the input handler (specifically its node) to the global
input_handler_list. The input_handler_list is central to the functionality
of input core and is traversed in various places in input core. An example
of this is when a new input device is plugged in and gets registered with
input core.
The input_handler in probe is allocated as device managed memory. If a
probe failure occurs after input_register_handler() the input_handler
memory is freed, yet it will remain in the input_handler_list. This
effectively means the input_handler_list contains a dangling pointer
to data belonging to a freed input handler.
This causes an issue when any other input device is plugged in - in my
case I had an old PixArt HP USB optical mouse and I decided to
plug it in after a failure occurred after input_register_handler().
This lead to the registration of this input device via
input_register_device which involves traversing over every handler
in the corrupted input_handler_list and calling input_attach_handler(),
giving each handler a chance to bind to newly registered device.
The core of this bug is a UAF which causes memory corruption of
input_handler_list and to fix it we must ensure the input handler is
unregistered from input core, this is done through
input_unregister_handler().
[ 63.191597] ==================================================================
[ 63.192094] BUG: KASAN: slab-use-after-free in input_attach_handler.isra.0+0x1a9/0x1e0
[ 63.192094] Read of size 8 at addr ffff888105ea7c80 by task kworker/0:2/54
[ 63.192094]
[ 63.192094] CPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted 6.16.0-rc2-00321-g2aa6621d
[ 63.192094] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.164
[ 63.192094] Workqueue: usb_hub_wq hub_event
[ 63.192094] Call Trace:
[ 63.192094] <TASK>
[ 63.192094] dump_stack_lvl+0x53/0x70
[ 63.192094] print_report+0xce/0x670
[ 63.192094] kasan_report+0xce/0x100
[ 63.192094] input_attach_handler.isra.0+0x1a9/0x1e0
[ 63.192094] input_register_device+0x76c/0xd00
[ 63.192094] hidinput_connect+0x686d/0xad60
[ 63.192094] hid_connect+0xf20/0x1b10
[ 63.192094] hid_hw_start+0x83/0x100
[ 63.192094] hid_device_probe+0x2d1/0x680
[ 63.192094] really_probe+0x1c3/0x690
[ 63.192094] __driver_probe_device+0x247/0x300
[ 63.192094] driver_probe_device+0x49/0x210
[ 63.192094] __device_attach_driver+0x160/0x320
[ 63.192094] bus_for_each_drv+0x10f/0x190
[ 63.192094] __device_attach+0x18e/0x370
[ 63.192094] bus_probe_device+0x123/0x170
[ 63.192094] device_add+0xd4d/0x1460
[ 63.192094] hid_add_device+0x30b/0x910
[ 63.192094] usbhid_probe+0x920/0xe00
[ 63.192094] usb_probe_interface+0x363/0x9a0
[ 63.192094] really_probe+0x1c3/0x690
[ 63.192094] __driver_probe_device+0x247/0x300
[ 63.192094] driver_probe_device+0x49/0x210
[ 63.192094] __device_attach_driver+0x160/0x320
[ 63.192094] bus_for_each_drv+0x10f/0x190
[ 63.192094] __device_attach+0x18e/0x370
[ 63.192094] bus_probe_device+0x123/0x170
[ 63.192094] device_add+0xd4d/0x1460
[ 63.192094] usb_set_configuration+0xd14/0x1880
[ 63.192094] usb_generic_driver_probe+0x78/0xb0
[ 63.192094] usb_probe_device+0xaa/0x2e0
[ 63.192094] really_probe+0x1c3/0x690
[ 63.192094] __driver_probe_device+0x247/0x300
[ 63.192094] driver_probe_device+0x49/0x210
[ 63.192094] __device_attach_driver+0x160/0x320
[ 63.192094] bus_for_each_drv+0x10f/0x190
[ 63.192094] __device_attach+0x18e/0x370
[ 63.192094] bus_probe_device+0x123/0x170
[ 63.192094] device_add+0xd4d/0x1460
[ 63.192094] usb_new_device+0x7b4/0x1000
[ 63.192094] hub_event+0x234d/0x3fa0
[ 63.192094] process_one_work+0x5bf/0xfe0
[ 63.192094] worker_thread+0x777/0x13a0
[ 63.192094] </TASK>
[ 63.192094]
[ 63.192094] Allocated by task 54:
[ 63.192094] kasan_save_stack+0x33/0x60
[ 63.192094] kasan_save_track+0x14/0x30
[ 63.192094] __kasan_kmalloc+0x8f/0xa0
[ 63.192094] __kmalloc_node_track_caller_noprof+0x195/0x420
[ 63.192094] devm_kmalloc+0x74/0x1e0
[ 63.192094] appletb_kbd_probe+0x39/0x440
[ 63.192094] hid_device_probe+0x2d1/0x680
[ 63.192094] really_probe+0x1c3/0x690
[ 63.192094] __driver_probe_device+0x247/0x300
[ 63.192094] driver_probe_device+0x49/0x210
[ 63.192094] __device_attach_driver+0x160/0x320
[...]
[ 63.192094]
[ 63.192094] Freed by task 54:
[ 63.192094] kasan_save_stack+0x33/0x60
[ 63.192094] kasan_save_track+0x14/0x30
[ 63.192094] kasan_save_free_info+0x3b/0x60
[ 63.192094] __kasan_slab_free+0x37/0x50
[ 63.192094] kfree+0xcf/0x360
[ 63.192094] devres_release_group+0x1f8/0x3c0
[ 63.192094] hid_device_probe+0x315/0x680
[ 63.192094] really_probe+0x1c3/0x690
[ 63.192094] __driver_probe_device+0x247/0x300
[ 63.192094] driver_probe_device+0x49/0x210
[ 63.192094] __device_attach_driver+0x160/0x320
[...]
The Linux kernel CVE team has assigned CVE-2025-38394 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.15 with commit 7d62ba8deacf94f546a0b9dd9bc86617343187a3 and fixed in 6.15.6 with commit 6ad40b07e15c29712d9a4b8096914ccd82e3fc17
Issue introduced in 6.15 with commit 7d62ba8deacf94f546a0b9dd9bc86617343187a3 and fixed in 6.16-rc5 with commit c80f2b047d5cc42fbd2dff9d1942d4ba7545100f
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2025-38394
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
drivers/hid/hid-appletb-kbd.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/6ad40b07e15c29712d9a4b8096914ccd82e3fc17
https://git.kernel.org/stable/c/c80f2b047d5cc42fbd2dff9d1942d4ba7545100f
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