From: Ming Lei <tom.leiming-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org>
To: "David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>,
Greg Kroah-Hartman
<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public•gmane.org>
Cc: netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
linux-usb-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
Ming Lei <tom.leiming-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org>,
stable-DgEjT+Ai2ygdnm+yROfE0A@public•gmane.org,
Sebastian Andrzej Siewior
<bigeasy-hfZtesqFncYOwBW4kG4KsQ@public•gmane.org>,
Alan Stern
<stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public•gmane.org>,
Oliver Neukum <oliver-GvhC2dPhHPQdnm+yROfE0A@public•gmane.org>
Subject: [PATCH 1/2] usbnet: increase URB reference count before usb_unlink_urb
Date: Thu, 22 Mar 2012 21:22:18 +0800 [thread overview]
Message-ID: <1332422538-6597-1-git-send-email-tom.leiming@gmail.com> (raw)
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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next reply other threads:[~2012-03-22 13:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-22 13:22 Ming Lei [this message]
2012-03-22 14:35 ` [PATCH 1/2] usbnet: increase URB reference count before usb_unlink_urb Greg Kroah-Hartman
[not found] ` <20120322143553.GC19835-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2012-03-22 23:33 ` David Miller
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