CVE-2022-49755

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait While performing fast composition switch, there is a possibility that the process of ffs_ep0_write/ffs_ep0_read get into a race condition due to ep0req being freed up from functionfs_unbind. Consider the scenario that the ffs_ep0_write calls the ffs_ep0_queue_wait by taking a lock &ffs->ev.waitq.lock. However, the functionfs_unbind isn't bounded so it can go ahead and mark the ep0req to NULL, and since there is no NULL check in ffs_ep0_queue_wait we will end up in use-after-free. Fix this by making a serialized execution between the two functions using a mutex_lock(ffs->mutex).

• linux linux kernel (>= 2.6.35 < 4.14.305) • linux linux kernel (>= 4.15 < 4.19.272) • linux linux kernel (>= 4.20 < 5.4.231) • linux linux kernel (>= 5.5 < 5.10.166) • linux linux kernel (>= 5.11 < 5.15.91) • linux linux kernel (>= 5.16 < 6.1.9) • linux linux kernel 6.2