⚪ ALSA: usb: 6fire: Avoid embedded URBs (Linux Linux)

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb: 6fire: Avoid embedded URBs The USB 6fire driver uses URBs embedded in different structs for PCM, MIDI and communication, and this is basically a buggy implementation nowadays; since a URB is managed with a refcount, this may lead to a UAF when the URB is released asynchronously. For addressing the problem, this patch converts those embedded URBs to ones that are properly allocated via usb_alloc_urb(). The pcm_urb.packets[] is gone, as it's allocated by usb_alloc_urb(), hence it's found in urb.iso_frame_desc[] instead. The conversions are rather straightforward; each embedded struct urb is changed to a pointer, and its callers are updated accordingly. The resource for those structs are released in the common destructor functions (usb6fire_comm_free(), etc), which are called at both the init error path and the disconnect. No functional changes, only compile-tested.