[PATCH 3.16 056/136] USB: iowarrior: fix use-after-free on release

Ben Hutchings
2019-12-17T00:57:39Z

From: Johan Hovold <johan@kernel.org>

commit 80cd5479b525093a56ef768553045741af61b250 upstream.

The driver was accessing its struct usb_interface from its release()
callback without holding a reference. This would lead to a
use-after-free whenever debugging was enabled and the device was
disconnected while its character device was open.

Fixes: 549e83500b80 ("USB: iowarrior: Convert local dbg macro to dev_dbg")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191009104846.5925-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/misc/iowarrior.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -248,6 +248,7 @@ static inline void iowarrior_delete(stru
kfree(dev->int_in_buffer);
usb_free_urb(dev->int_in_urb);
kfree(dev->read_queue);
+ usb_put_intf(dev->interface);
kfree(dev);
}

@@ -782,7 +783,7 @@ static int iowarrior_probe(struct usb_in
init_waitqueue_head(&dev->write_wait);

dev->udev = udev;
- dev->interface = interface;
+ dev->interface = usb_get_intf(interface);

iface_desc = interface->cur_altsetting;
dev->product_id = le16_to_cpu(udev->descriptor.idProduct);