Schspa Shi 216e7f47d0 usb: gadget: fix race when gadget driver register via ioctl ... commit 5f0b5f4d50 upstream. The usb_gadget_register_driver can be called multi time by to threads via USB_RAW_IOCTL_RUN ioctl syscall, which will lead to multiple registrations. Call trace: driver_register+0x220/0x3a0 drivers/base/driver.c:171 usb_gadget_register_driver_owner+0xfb/0x1e0 drivers/usb/gadget/udc/core.c:1546 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:513 [inline] raw_ioctl+0x1883/0x2730 drivers/usb/gadget/legacy/raw_gadget.c:1220 ioctl USB_RAW_IOCTL_RUN This routine allows two processes to register the same driver instance via ioctl syscall. which lead to a race condition. Please refer to the following scenarios. T1 T2 ------------------------------------------------------------------ usb_gadget_register_driver_owner driver_register driver_register driver_find driver_find bus_add_driver bus_add_driver priv alloced <context switch> drv->p = priv; <schedule out> kobject_init_and_add // refcount = 1; //couldn't find an available UDC or it's busy <context switch> priv alloced drv->priv = priv; kobject_init_and_add ---> refcount = 1 <------ // register success <context switch> ===================== another ioctl/process ====================== driver_register driver_find k = kset_find_obj() ---> refcount = 2 <------ <context out> driver_unregister // drv->p become T2's priv ---> refcount = 1 <------ <context switch> kobject_put(k) ---> refcount = 0 <------ return priv->driver; --------UAF here---------- There will be UAF in this scenario. We can fix it by adding a new STATE_DEV_REGISTERING device state to avoid double register. Reported-by: syzbot+dc7c3ca638e773db07f6@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/000000000000e66c2805de55b15a@google.com/ Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Signed-off-by: Schspa Shi <schspa@gmail.com> Link: https://lore.kernel.org/r/20220508150247.38204-1-schspa@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-05-25 09:58:56 +02:00
..
function	usb: gadget: uvc: allow for application to cleanly shutdown	2022-05-18 10:28:19 +02:00
legacy	usb: gadget: fix race when gadget driver register via ioctl	2022-05-25 09:58:56 +02:00
udc	usb: gadget: tegra-xudc: Fix control endpoint's definitions	2022-04-13 19:27:09 +02:00
composite.c	USB: gadget: validate interface OS descriptor requests	2022-02-11 10:59:12 +01:00
config.c	usb: fix various gadget panics on 10gbps cabling	2021-06-09 10:40:08 +02:00
configfs.c	usb: gadget: configfs: clear deactivation flag in configfs_composite_unbind()	2022-05-09 09:16:13 +02:00
configfs.h
epautoconf.c	usb: gadget: fix for a typo that conveys logically-inverted information.	2021-09-14 10:27:54 +02:00
functions.c
Kconfig	usb: gadget: uvc: add scatter gather support	2021-07-27 15:59:19 +02:00
Makefile
u_f.c
u_f.h
u_os_desc.h
usbstring.c