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Aleksandr Nogikh
f95e57b661
commit 00e2071f6d upstream.
The usbtest driver relies on the driver_info field of struct usb_device_id
to point to a valid struct usbtest_info descriptor. This structure contains
essential test configurations, such as endpoint addresses and test modes,
which are required during probe.
When a user dynamically adds a new device ID via the sysfs new_id
interface without specifying a reference device, the USB core initializes
driver_info to 0 (NULL). When a matching device is subsequently probed,
usbtest_probe() unconditionally casts driver_info to a struct usbtest_info
pointer and dereferences it, leading to a NULL pointer dereference crash:
Oops: general protection fault, probably for non-canonical address
0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
RIP: 0010:usbtest_probe+0x3b9/0x1280 drivers/usb/misc/usbtest.c:2822
Because usbtest strictly requires pre-defined usbtest_info descriptors
to function, dynamic ID binding via sysfs is fundamentally unsupported
for this driver.
Fix this by setting .no_dynamic_id = 1 on usbtest_driver. This instructs
the USB core to skip creating the new_id and remove_id sysfs interfaces
for usbtest, preventing invalid dynamic ID entries from being created.
Cc: stable@vger.kernel.org
Reported-by: syzbot+7e1e5911f9eac50bedc7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7e1e5911f9eac50bedc7
Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
Tested-by: syzbot@syzkaller.appspotmail.com
Link: https://patch.msgid.link/20260806152651.2370795-1-nogikh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.