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.
