Commit ef61eb43 authored Apr 23, 2019 by Alan Stern Committed by Greg Kroah-Hartman Apr 25, 2019

USB: yurex: Fix protection fault after device removal



The syzkaller USB fuzzer found a general-protection-fault bug in the
yurex driver.  The fault occurs when a device has been unplugged; the
driver's interrupt-URB handler logs an error message referring to the
device by name, after the device has been unregistered and its name
deallocated.

This problem is caused by the fact that the interrupt URB isn't
cancelled until the driver's private data structure is released, which
can happen long after the device is gone.  The cure is to make sure
that the interrupt URB is killed before yurex_disconnect() returns;
this is exactly the sort of thing that usb_poison_urb() was meant for.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by:  <syzbot+2eb9121678bdb36e6d57@syzkaller.appspotmail.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent c409ca3b

drivers/usb/misc/yurex.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -314,6 +314,7 @@ static void yurex_disconnect(struct usb_interface *interface)
		usb_deregister_dev(interface, &yurex_class);

		/* prevent more I/O from starting */
		usb_poison_urb(dev->urb);
		mutex_lock(&dev->io_mutex);
		dev->interface = NULL;
		mutex_unlock(&dev->io_mutex);

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