The driver was using its struct usb_interface pointer as an inverted
disconnected flag, but was setting it to NULL without making sure all
code paths that used it were done with it.
Before commit ef61eb43ada6 ("USB: yurex: Fix protection fault after
device removal") this included the interrupt-in completion handler, but
there are further accesses in dev_err and dev_dbg statements in
yurex_write() and the driver-data destructor (sic!).
Fix this by unconditionally stopping also the control URB at disconnect
and by using a dedicated disconnected flag.
Note that we need to take a reference to the struct usb_interface to
avoid a use-after-free in the destructor whenever the device was
disconnected while the character device was still open.
Fixes: aadd6472d904 ("USB: yurex.c: remove dbg() usage")
Fixes: 45714104b9e8 ("USB: yurex.c: remove err() usage")
Cc: stable <stable@xxxxxxxxxxxxxxx> # 3.5: ef61eb43ada6
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/misc/yurex.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/misc/yurex.c b/drivers/usb/misc/yurex.c
index 8d52d4336c29..be0505b8b5d4 100644
--- a/drivers/usb/misc/yurex.c
+++ b/drivers/usb/misc/yurex.c
@@ -60,6 +60,7 @@ struct usb_yurex {
struct kref kref;
struct mutex io_mutex;
+ unsigned long disconnected:1;
struct fasync_struct *async_queue;
wait_queue_head_t waitq;
@@ -107,6 +108,7 @@ static void yurex_delete(struct kref *kref)
dev->int_buffer, dev->urb->transfer_dma);
usb_free_urb(dev->urb);
}
+ usb_put_intf(dev->interface);
usb_put_dev(dev->udev);
kfree(dev);
}
@@ -205,7 +207,7 @@ static int yurex_probe(struct usb_interface *interface, const struct usb_device_
init_waitqueue_head(&dev->waitq);
dev->udev = usb_get_dev(interface_to_usbdev(interface));
- dev->interface = interface;
+ dev->interface = usb_get_intf(interface);
/* set up the endpoint information */
iface_desc = interface->cur_altsetting;
@@ -316,8 +318,9 @@ static void yurex_disconnect(struct usb_interface *interface)
/* prevent more I/O from starting */
usb_poison_urb(dev->urb);
+ usb_poison_urb(dev->cntl_urb);
mutex_lock(&dev->io_mutex);
- dev->interface = NULL;
+ dev->disconnected = 1;
mutex_unlock(&dev->io_mutex);
/* wakeup waiters */
@@ -405,7 +408,7 @@ static ssize_t yurex_read(struct file *file, char __user *buffer, size_t count,
dev = file->private_data;
mutex_lock(&dev->io_mutex);
- if (!dev->interface) { /* already disconnected */
+ if (dev->disconnected) { /* already disconnected */
mutex_unlock(&dev->io_mutex);
return -ENODEV;
}
@@ -440,7 +443,7 @@ static ssize_t yurex_write(struct file *file, const char __user *user_buffer,
goto error;
mutex_lock(&dev->io_mutex);
- if (!dev->interface) { /* already disconnected */
+ if (dev->disconnected) { /* already disconnected */
mutex_unlock(&dev->io_mutex);
retval = -ENODEV;
goto error;
--
2.23.0
