| Message ID | 1332422538-6597-1-git-send-email-tom.leiming@gmail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thu, Mar 22, 2012 at 09:22:18PM +0800, Ming Lei wrote: > Commit 4231d47e6fe69f061f96c98c30eaf9fb4c14b96d(net/usbnet: avoid > recursive locking in usbnet_stop()) fixes the recursive locking > problem by releasing the skb queue lock, but it makes usb_unlink_urb > racing with defer_bh, and the URB to being unlinked may be freed before > or during calling usb_unlink_urb, so use-after-free problem may be > triggerd inside usb_unlink_urb. > > The patch fixes the use-after-free problem by increasing URB > reference count with skb queue lock held before calling > usb_unlink_urb, so the URB won't be freed until return from > usb_unlink_urb. > > Cc: stable@kernel.org > Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > Cc: Alan Stern <stern@rowland.harvard.edu> > Cc: Oliver Neukum <oliver@neukum.org> > Reported-by: Dave Jones <davej@redhat.com> > Signed-off-by: Ming Lei <tom.leiming@gmail.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Date: Thu, 22 Mar 2012 07:35:53 -0700 > On Thu, Mar 22, 2012 at 09:22:18PM +0800, Ming Lei wrote: >> Commit 4231d47e6fe69f061f96c98c30eaf9fb4c14b96d(net/usbnet: avoid >> recursive locking in usbnet_stop()) fixes the recursive locking >> problem by releasing the skb queue lock, but it makes usb_unlink_urb >> racing with defer_bh, and the URB to being unlinked may be freed before >> or during calling usb_unlink_urb, so use-after-free problem may be >> triggerd inside usb_unlink_urb. >> >> The patch fixes the use-after-free problem by increasing URB >> reference count with skb queue lock held before calling >> usb_unlink_urb, so the URB won't be freed until return from >> usb_unlink_urb. >> >> Cc: stable@kernel.org >> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> >> Cc: Alan Stern <stern@rowland.harvard.edu> >> Cc: Oliver Neukum <oliver@neukum.org> >> Reported-by: Dave Jones <davej@redhat.com> >> Signed-off-by: Ming Lei <tom.leiming@gmail.com> > > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index 4b8b52c..febfdce 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -589,6 +589,14 @@ static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q) entry = (struct skb_data *) skb->cb; urb = entry->urb; + /* + * Get reference count of the URB to avoid it to be + * freed during usb_unlink_urb, which may trigger + * use-after-free problem inside usb_unlink_urb since + * usb_unlink_urb is always racing with .complete + * handler(include defer_bh). + */ + usb_get_urb(urb); spin_unlock_irqrestore(&q->lock, flags); // during some PM-driven resume scenarios, // these (async) unlinks complete immediately @@ -597,6 +605,7 @@ static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q) netdev_dbg(dev->net, "unlink urb err, %d\n", retval); else count++; + usb_put_urb(urb); spin_lock_irqsave(&q->lock, flags); } spin_unlock_irqrestore (&q->lock, flags);
Commit 4231d47e6fe69f061f96c98c30eaf9fb4c14b96d(net/usbnet: avoid recursive locking in usbnet_stop()) fixes the recursive locking problem by releasing the skb queue lock, but it makes usb_unlink_urb racing with defer_bh, and the URB to being unlinked may be freed before or during calling usb_unlink_urb, so use-after-free problem may be triggerd inside usb_unlink_urb. The patch fixes the use-after-free problem by increasing URB reference count with skb queue lock held before calling usb_unlink_urb, so the URB won't be freed until return from usb_unlink_urb. Cc: stable@kernel.org Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Oliver Neukum <oliver@neukum.org> Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Ming Lei <tom.leiming@gmail.com> --- drivers/net/usb/usbnet.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-)