drivers/usb/misc/iowarrior.c: NULL dereference

drivers/usb/misc/iowarrior.c: NULL dereference

[Adrian Bunk]

The Coverity checker spotted the following NULL dereference:

<--  snip  -->

...
static ssize_t iowarrior_write(struct file *file,
                               const char __user *user_buffer,
                               size_t count, loff_t *ppos)
{
...
                if (!int_out_urb) {
                        retval = -ENOMEM;
                        dbg("%s Unable to allocate urb ", __func__);
                        goto error;
...
error:
        usb_buffer_free(dev->udev, dev->report_size, buf,
                        int_out_urb->transfer_dma);
...                     ^^^^^^^^^^^^^^^^^^^^^^^^^

<--  snip  -->

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: [linux-usb-devel] drivers/usb/misc/iowarrior.c: NULL dereference

[Oliver Neukum]

Am Montag, 19. März 2007 10:25 schrieb Adrian Bunk:

> static ssize_t iowarrior_write(struct file *file,
>                                const char __user *user_buffer,
>                                size_t count, loff_t *ppos)
> {
> ...
>                 if (!int_out_urb) {
>                         retval = -ENOMEM;
>                         dbg("%s Unable to allocate urb ", __func__);
>                         goto error;
> ...
> error:
>         usb_buffer_free(dev->udev, dev->report_size, buf,
>                         int_out_urb->transfer_dma);
> ...                     ^^^^^^^^^^^^^^^^^^^^^^^^^

Yes, that's a bug. The fix is compiling.

	Regards
		Oliver

[PATCH]Re: [linux-usb-devel] drivers/usb/misc/iowarrior.c: NULL dereference

[Oliver Neukum]

Am Montag, 19. März 2007 10:25 schrieb Adrian Bunk:
> The Coverity checker spotted the following NULL dereference:

And this fixes an oops upon allocation failures.

	Regards
		Oliver

Signed-off-by: Oliver Neukum <oneukum@suse.de>
-----

--- linux-2.6.21-rc4/drivers/usb/misc/iowarrior.c.alt	2007-03-19 11:05:37.000000000 +0100
+++ linux-2.6.21-rc4/drivers/usb/misc/iowarrior.c	2007-03-19 11:07:30.000000000 +0100
@@ -417,14 +417,14 @@
 		if (!int_out_urb) {
 			retval = -ENOMEM;
 			dbg("%s Unable to allocate urb ", __func__);
-			goto error;
+			goto error_no_urb;
 		}
 		buf = usb_buffer_alloc(dev->udev, dev->report_size,
 				       GFP_KERNEL, &int_out_urb->transfer_dma);
 		if (!buf) {
 			retval = -ENOMEM;
 			dbg("%s Unable to allocate buffer ", __func__);
-			goto error;
+			goto error_no_buffer;
 		}
 		usb_fill_int_urb(int_out_urb, dev->udev,
 				 usb_sndintpipe(dev->udev,
@@ -459,7 +459,9 @@
 error:
 	usb_buffer_free(dev->udev, dev->report_size, buf,
 			int_out_urb->transfer_dma);
+error_no_buffer:
 	usb_free_urb(int_out_urb);
+error_no_urb:
 	atomic_dec(&dev->write_busy);
 	wake_up_interruptible(&dev->write_wait);
 exit: