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authorOliver Neukum <oneukum@suse.com>2019-10-16 15:40:41 +0200
committerOliver Neukum <oneukum@suse.com>2019-10-16 15:40:41 +0200
commit081bf277f3223e3b97a2a5f193369dffdbe94868 (patch)
tree59153cc870de30c027c62ff783ed3d3c37563bdd
parentc88fa29d2e925bc88daa2dfaa1cfb747db758fd9 (diff)
USB: legousbtower: fix potential NULL-deref on disconnect
(bsc#1142635). suse-commit: cddc12e39efe1e34bf0d54036680595efc570390
-rw-r--r--drivers/usb/misc/legousbtower.c26
1 files changed, 15 insertions, 11 deletions
diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
index 84cf009a2546..d68541d28b9b 100644
--- a/drivers/usb/misc/legousbtower.c
+++ b/drivers/usb/misc/legousbtower.c
@@ -196,6 +196,7 @@ struct lego_usb_tower {
unsigned char minor; /* the starting minor number for this device */
int open_count; /* number of times this port has been opened */
+ unsigned long disconnected:1;
char* read_buffer;
size_t read_buffer_length; /* this much came in */
@@ -295,8 +296,6 @@ static inline void lego_usb_tower_debug_data(struct device *dev,
*/
static inline void tower_delete (struct lego_usb_tower *dev)
{
- tower_abort_transfers (dev);
-
/* free data structures */
usb_free_urb(dev->interrupt_in_urb);
usb_free_urb(dev->interrupt_out_urb);
@@ -436,7 +435,8 @@ static int tower_release (struct inode *inode, struct file *file)
retval = -ENODEV;
goto unlock_exit;
}
- if (dev->udev == NULL) {
+
+ if (dev->disconnected) {
/* the device was unplugged before the file was released */
/* unlock here as tower_delete frees dev */
@@ -472,10 +472,9 @@ static void tower_abort_transfers (struct lego_usb_tower *dev)
if (dev->interrupt_in_running) {
dev->interrupt_in_running = 0;
mb();
- if (dev->udev)
- usb_kill_urb (dev->interrupt_in_urb);
+ usb_kill_urb(dev->interrupt_in_urb);
}
- if (dev->interrupt_out_busy && dev->udev)
+ if (dev->interrupt_out_busy)
usb_kill_urb(dev->interrupt_out_urb);
}
@@ -511,7 +510,7 @@ static unsigned int tower_poll (struct file *file, poll_table *wait)
dev = file->private_data;
- if (!dev->udev)
+ if (dev->disconnected)
return POLLERR | POLLHUP;
poll_wait(file, &dev->read_wait, wait);
@@ -558,7 +557,7 @@ static ssize_t tower_read (struct file *file, char __user *buffer, size_t count,
}
/* verify that the device wasn't unplugged */
- if (dev->udev == NULL) {
+ if (dev->disconnected) {
retval = -ENODEV;
pr_err("No device or device unplugged %d\n", retval);
goto unlock_exit;
@@ -644,7 +643,7 @@ static ssize_t tower_write (struct file *file, const char __user *buffer, size_t
}
/* verify that the device wasn't unplugged */
- if (dev->udev == NULL) {
+ if (dev->disconnected) {
retval = -ENODEV;
pr_err("No device or device unplugged %d\n", retval);
goto unlock_exit;
@@ -753,7 +752,7 @@ static void tower_interrupt_in_callback (struct urb *urb)
resubmit:
/* resubmit if we're still running */
- if (dev->interrupt_in_running && dev->udev) {
+ if (dev->interrupt_in_running) {
retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
if (retval)
dev_err(&dev->udev->dev,
@@ -818,6 +817,7 @@ static int tower_probe (struct usb_interface *interface, const struct usb_device
dev->udev = udev;
dev->open_count = 0;
+ dev->disconnected = 0;
dev->read_buffer = NULL;
dev->read_buffer_length = 0;
@@ -943,6 +943,10 @@ static void tower_disconnect (struct usb_interface *interface)
/* give back our minor and prevent further open() */
usb_deregister_dev (interface, &tower_class);
+ /* stop I/O */
+ usb_poison_urb(dev->interrupt_in_urb);
+ usb_poison_urb(dev->interrupt_out_urb);
+
mutex_lock(&dev->lock);
/* if the device is not opened, then we clean up right now */
@@ -950,7 +954,7 @@ static void tower_disconnect (struct usb_interface *interface)
mutex_unlock(&dev->lock);
tower_delete (dev);
} else {
- dev->udev = NULL;
+ dev->disconnected = 1;
/* wake up pollers */
wake_up_interruptible_all(&dev->read_wait);
wake_up_interruptible_all(&dev->write_wait);