patch "USB: fix linked-list corruption in rh_call_control()" added to usb-linus

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

USB: fix linked-list corruption in rh_call_control()

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: Alan Stern <[email protected]>
Date: Fri, 24 Mar 2017 13:38:28 -0400
Subject: USB: fix linked-list corruption in rh_call_control()

Using KASAN, Dmitry found a bug in the rh_call_control() routine: If buffer allocation fails, the routine returns immediately without unlinking its URB from the control endpoint, eventually leading to linked-list corruption.

This patch fixes the problem by jumping to the end of the routine (where the URB is unlinked) when an allocation failure occurs.

---
 drivers/usb/core/hcd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

index 612fab6e54fb..79bdca5cb9c7 100644
@@ -520,8 +520,10 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
 	 */
 	tbuf_size =  max_t(u16, sizeof(struct usb_hub_descriptor), wLength);
 	tbuf = kzalloc(tbuf_size, GFP_KERNEL);
-	if (!tbuf)
-		return -ENOMEM;
+	if (!tbuf) {
+		status = -ENOMEM;
+		goto err_alloc;
+	}
 
 	bufp = tbuf;
 

@@ -734,6 +736,7 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
 	}
 
 	kfree(tbuf);
+ err_alloc:
 
 	/* any errors get returned through the urb completion */
 	spin_lock_irq(&hcd_root_hub_lock);

2.12.1