netdev - [PATCH net] sierra_net: Fix use-after-free on unbind

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <80e88f61ca68c36ebce5d17dfcaa8e956e19fb2f.1655196227.git.lukas@wunner.de>
Date:   Tue, 14 Jun 2022 10:50:24 +0200
From:   Lukas Wunner <lukas@...ner.de>
To:     Oliver Neukum <oneukum@...e.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Eric Dumazet <edumazet@...gle.com>
Cc:     netdev@...r.kernel.org, linux-usb@...r.kernel.org,
        Dan Williams <dan.j.williams@...el.com>
Subject: [PATCH net] sierra_net: Fix use-after-free on unbind

On unbind, the Sierra USB WWAN driver cancels the sierra_net_kevent()
work, then stops polling for interrupts by calling usbnet_status_stop().

However the interrupt handler sierra_net_status() may re-schedule the
work after it's been canceled and thus cause a use-after-free.

Fix by inverting the teardown order.

Fixes: 7b0c5f21f348 ("sierra_net: keep status interrupt URB active")
Signed-off-by: Lukas Wunner <lukas@...ner.de>
Cc: stable@...r.kernel.org # v3.10+
Cc: Dan Williams <dan.j.williams@...el.com>
---
 drivers/net/usb/sierra_net.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/sierra_net.c b/drivers/net/usb/sierra_net.c
index bb4cbe8fc846..197e1356ae98 100644
--- a/drivers/net/usb/sierra_net.c
+++ b/drivers/net/usb/sierra_net.c
@@ -758,6 +758,8 @@ static void sierra_net_unbind(struct usbnet *dev, struct usb_interface *intf)
 
 	dev_dbg(&dev->udev->dev, "%s", __func__);
 
+	usbnet_status_stop(dev);
+
 	/* kill the timer and work */
 	del_timer_sync(&priv->sync_timer);
 	cancel_work_sync(&priv->sierra_net_kevent);
@@ -769,8 +771,6 @@ static void sierra_net_unbind(struct usbnet *dev, struct usb_interface *intf)
 		netdev_err(dev->net,
 			"usb_control_msg failed, status %d\n", status);
 
-	usbnet_status_stop(dev);
-
 	sierra_net_set_private(dev, NULL);
 	kfree(priv);
 }
-- 
2.35.2