Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

nfc: pn533: Wait for out_urb's completion in pn533_usb_send_frame()

Fix a use-after-free that occurs in hcd when in_urb sent from pn533_usb_send_frame() is completed earlier than out_urb. Its callback frees the skb data in pn533_send_async_complete() that is used as a transfer buffer of out_urb. Wait before sending in_urb until the callback of out_urb is called. To modify the callback of out_urb alone, separate the complete function of out_urb and ack_urb.

Found by a modified version of syzkaller.

BUG: KASAN: use-after-free in dummy_timer Call Trace: memcpy (mm/kasan/shadow.c:65) dummy_perform_transfer (drivers/usb/gadget/udc/dummy_hcd.c:1352) transfer (drivers/usb/gadget/udc/dummy_hcd.c:1453) dummy_timer (drivers/usb/gadget/udc/dummy_hcd.c:1972) arch_static_branch (arch/x86/include/asm/jump_label.h:27) static_key_false (include/linux/jump_label.h:207) timer_expire_exit (include/trace/events/timer.h:127) call_timer_fn (kernel/time/timer.c:1475) expire_timers (kernel/time/timer.c:1519) __run_timers (kernel/time/timer.c:1790) run_timer_softirq (kernel/time/timer.c:1803)