Description
In the Linux kernel, the following vulnerability has been resolved: USB: Gadget: core: Help prevent panic during UVC unconfigure Avichal Rakesh reported a kernel panic that occurred when the UVC gadget driver was removed from a gadget's configuration. The panic involves a somewhat complicated interaction between the kernel driver and a userspace component (as described in the Link tag below), but the analysis did make one thing clear: The Gadget core should accomodate gadget drivers calling usb_gadget_deactivate() as part of their unbind procedure. Currently this doesn't work. gadget_unbind_driver() calls driver->unbind() while holding the udc->connect_lock mutex, and usb_gadget_deactivate() attempts to acquire that mutex, which will result in a deadlock. The simple fix is for gadget_unbind_driver() to release the mutex when invoking the ->unbind() callback. There is no particular reason for it to be holding the mutex at that time, and the mutex isn't held while the ->bind() callback is invoked. So we'll drop the mutex before performing the unbind callback and reacquire it afterward. We'll also add a couple of comments to usb_gadget_activate() and usb_gadget_deactivate(). Because they run in process context they must not be called from a gadget driver's ->disconnect() callback, which (according to the kerneldoc for struct usb_gadget_driver in include/linux/usb/gadget.h) may run in interrupt context. This may help prevent similar bugs from arising in the future.
Product status
d8195536ce2624e2947d9f56b1a61e7a27874bd3 before bed19d95fcb9c98dfaa9585922b39a2dfba7898d
286d9975a838d0a54da049765fa1d1fb96b89682 before 8c1edc00db65f6d4408b3d1cd845e8da3b9e0ca4
286d9975a838d0a54da049765fa1d1fb96b89682 before 65dadb2beeb7360232b09ebc4585b54475dfee06
85102a45c7390caf124a3a5796574446f1e037b9
6.4
Any version before 6.4
6.1.46
6.4.11
6.5
References
git.kernel.org/...c/bed19d95fcb9c98dfaa9585922b39a2dfba7898d
git.kernel.org/...c/8c1edc00db65f6d4408b3d1cd845e8da3b9e0ca4
git.kernel.org/...c/65dadb2beeb7360232b09ebc4585b54475dfee06