patch "USB: c67x00: fix use after free in c67x00_giveback_urb" added to usb-linus

This is a note to let you know that I've just added the patch titled

USB: c67x00: fix use after free in c67x00_giveback_urb

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 211f08347355cba1f769bbf3355816a12b3ddd55 Mon Sep 17 00:00:00 2001
From: Tom Rix <[email protected]>
Date: Wed, 8 Jul 2020 06:12:43 -0700
Subject: USB: c67x00: fix use after free in c67x00_giveback_urb

clang static analysis flags this error

c67x00-sched.c:489:55: warning: Use of memory after it is freed [unix.Malloc]

        usb_hcd_giveback_urb(c67x00_hcd_to_hcd(c67x00), urb, urbp->status);
                                                             ^~~~~~~~~~~~

Problem happens in this block of code

	c67x00_release_urb(c67x00, urb);
	usb_hcd_unlink_urb_from_ep(c67x00_hcd_to_hcd(c67x00), urb);
	spin_unlock(&c67x00->lock);
	usb_hcd_giveback_urb(c67x00_hcd_to_hcd(c67x00), urb, urbp->status);

In the call to c67x00_release_urb has this freeing of urbp

	urbp = urb->hcpriv;
	urb->hcpriv = NULL;
	list_del(&urbp->hep_node);
	kfree(urbp);

And so urbp is freed before usb_hcd_giveback_urb uses it as its 3rd parameter.

Since all is required is the status, pass the status directly as is done in c64x00_urb_dequeue

---
 drivers/usb/c67x00/c67x00-sched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 633c52de3bb3..9865750bc31e 100644
@@ -486,7 +486,7 @@ c67x00_giveback_urb(struct c67x00_hcd *c67x00, struct urb *urb, int status)
 	c67x00_release_urb(c67x00, urb);
 	usb_hcd_unlink_urb_from_ep(c67x00_hcd_to_hcd(c67x00), urb);
 	spin_unlock(&c67x00->lock);
-	usb_hcd_giveback_urb(c67x00_hcd_to_hcd(c67x00), urb, urbp->status);
+	usb_hcd_giveback_urb(c67x00_hcd_to_hcd(c67x00), urb, status);
 	spin_lock(&c67x00->lock);
 }
 

2.27.0