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Message-Id: <20210712060845.425566581@linuxfoundation.org>
Date: Mon, 12 Jul 2021 08:03:00 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Pavel Skripkin <paskripkin@...il.com>,
Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH 5.10 020/593] net: can: ems_usb: fix use-after-free in ems_usb_disconnect()
From: Pavel Skripkin <paskripkin@...il.com>
commit ab4a0b8fcb9a95c02909b62049811bd2e586aaa4 upstream.
In ems_usb_disconnect() dev pointer, which is netdev private data, is
used after free_candev() call:
| if (dev) {
| unregister_netdev(dev->netdev);
| free_candev(dev->netdev);
|
| unlink_all_urbs(dev);
|
| usb_free_urb(dev->intr_urb);
|
| kfree(dev->intr_in_buffer);
| kfree(dev->tx_msg_buffer);
| }
Fix it by simply moving free_candev() at the end of the block.
Fail log:
| BUG: KASAN: use-after-free in ems_usb_disconnect
| Read of size 8 at addr ffff88804e041008 by task kworker/1:2/2895
|
| CPU: 1 PID: 2895 Comm: kworker/1:2 Not tainted 5.13.0-rc5+ #164
| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.4
| Workqueue: usb_hub_wq hub_event
| Call Trace:
| dump_stack (lib/dump_stack.c:122)
| print_address_description.constprop.0.cold (mm/kasan/report.c:234)
| kasan_report.cold (mm/kasan/report.c:420 mm/kasan/report.c:436)
| ems_usb_disconnect (drivers/net/can/usb/ems_usb.c:683 drivers/net/can/usb/ems_usb.c:1058)
Fixes: 702171adeed3 ("ems_usb: Added support for EMS CPC-USB/ARM7 CAN/USB interface")
Link: https://lore.kernel.org/r/20210617185130.5834-1-paskripkin@gmail.com
Cc: linux-stable <stable@...r.kernel.org>
Signed-off-by: Pavel Skripkin <paskripkin@...il.com>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/net/can/usb/ems_usb.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -1053,7 +1053,6 @@ static void ems_usb_disconnect(struct us
if (dev) {
unregister_netdev(dev->netdev);
- free_candev(dev->netdev);
unlink_all_urbs(dev);
@@ -1061,6 +1060,8 @@ static void ems_usb_disconnect(struct us
kfree(dev->intr_in_buffer);
kfree(dev->tx_msg_buffer);
+
+ free_candev(dev->netdev);
}
}
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