* [PATCH 1/2] usbnet: increase URB reference count before usb_unlink_urb
@ 2012-03-22 13:22 Ming Lei
2012-03-22 14:35 ` Greg Kroah-Hartman
0 siblings, 1 reply; 3+ messages in thread
From: Ming Lei @ 2012-03-22 13:22 UTC (permalink / raw)
To: David S. Miller, Greg Kroah-Hartman
Cc: netdev-u79uwXL29TY76Z2rM5mHXA, linux-usb-u79uwXL29TY76Z2rM5mHXA,
Ming Lei, stable-DgEjT+Ai2ygdnm+yROfE0A,
Sebastian Andrzej Siewior, Alan Stern, Oliver Neukum
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-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
Cc: Sebastian Andrzej Siewior <bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Cc: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>
Cc: Oliver Neukum <oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org>
Reported-by: Dave Jones <davej-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Ming Lei <tom.leiming-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
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 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);
--
1.7.9.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 1/2] usbnet: increase URB reference count before usb_unlink_urb
2012-03-22 13:22 [PATCH 1/2] usbnet: increase URB reference count before usb_unlink_urb Ming Lei
@ 2012-03-22 14:35 ` Greg Kroah-Hartman
[not found] ` <20120322143553.GC19835-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: Greg Kroah-Hartman @ 2012-03-22 14:35 UTC (permalink / raw)
To: Ming Lei
Cc: David S. Miller, netdev, linux-usb, stable,
Sebastian Andrzej Siewior, Alan Stern, Oliver Neukum
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>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 1/2] usbnet: increase URB reference count before usb_unlink_urb
[not found] ` <20120322143553.GC19835-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
@ 2012-03-22 23:33 ` David Miller
0 siblings, 0 replies; 3+ messages in thread
From: David Miller @ 2012-03-22 23:33 UTC (permalink / raw)
To: gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r
Cc: tom.leiming-Re5JQEeQqe8AvxtiuMwx3w,
netdev-u79uwXL29TY76Z2rM5mHXA, linux-usb-u79uwXL29TY76Z2rM5mHXA,
stable-DgEjT+Ai2ygdnm+yROfE0A, bigeasy-hfZtesqFncYOwBW4kG4KsQ,
stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz,
oliver-GvhC2dPhHPQdnm+yROfE0A
From: Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.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-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
>> Cc: Sebastian Andrzej Siewior <bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
>> Cc: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>
>> Cc: Oliver Neukum <oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org>
>> Reported-by: Dave Jones <davej-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>> Signed-off-by: Ming Lei <tom.leiming-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>
> Acked-by: Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
Applied.
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2012-03-22 13:22 [PATCH 1/2] usbnet: increase URB reference count before usb_unlink_urb Ming Lei
2012-03-22 14:35 ` Greg Kroah-Hartman
[not found] ` <20120322143553.GC19835-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2012-03-22 23:33 ` David Miller
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