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| author | tom.leiming@gmail.com <tom.leiming@gmail.com> | 2012-03-22 03:22:18 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-03-22 19:32:34 -0400 |
| commit | 0956a8c20b23d429e79ff86d4325583fc06f9eb4 (patch) | |
| tree | 65adc5a7fc8b19ca046ba661692a75a65fd04e88 /drivers/net/usb | |
| parent | 1265fd616782ef03b98fd19f65c2b47fcd4ea11f (diff) | |
| download | lwn-0956a8c20b23d429e79ff86d4325583fc06f9eb4.tar.gz lwn-0956a8c20b23d429e79ff86d4325583fc06f9eb4.zip | |
usbnet: increase URB reference count before usb_unlink_urb
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/usb')
| -rw-r--r-- | drivers/net/usb/usbnet.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index 4b8b52ca09d8..febfdceeb9e5 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); |