[PATCH 4.18 204/350] usbip:vudc: BUG kmalloc-2048 (Not tainted): Poison overwritten

Greg Kroah-Hartman
2018-11-11T23:23:15Z

From: Shuah Khan (Samsung OSG) <shuah@kernel.org>

commit e28fd56ad5273be67d0fae5bedc7e1680e729952 upstream.

In rmmod path, usbip_vudc does platform_device_put() twice once from
platform_device_unregister() and then from put_vudc_device().

The second put results in:

BUG kmalloc-2048 (Not tainted): Poison overwritten error or
BUG: KASAN: use-after-free in kobject_put+0x1e/0x230 if KASAN is
enabled.

[ 169.042156] calling init+0x0/0x1000 [usbip_vudc] @ 1697
[ 169.042396] =============================================================================
[ 169.043678] probe of usbip-vudc.0 returned 1 after 350 usecs
[ 169.044508] BUG kmalloc-2048 (Not tainted): Poison overwritten
[ 169.044509] -----------------------------------------------------------------------------
...
[ 169.057849] INFO: Freed in device_release+0x2b/0x80 age=4223 cpu=3 pid=1693
[ 169.057852] kobject_put+0x86/0x1b0
[ 169.057853] 0xffffffffc0c30a96
[ 169.057855] __x64_sys_delete_module+0x157/0x240

Fix it to call platform_device_del() instead and let put_vudc_device() do
the platform_device_put().

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/usbip/vudc_main.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/usb/usbip/vudc_main.c
+++ b/drivers/usb/usbip/vudc_main.c
@@ -73,6 +73,10 @@ static int __init init(void)
cleanup:
list_for_each_entry_safe(udc_dev, udc_dev2, &vudc_devices, dev_entry) {
list_del(&udc_dev->dev_entry);
+ /*
+ * Just do platform_device_del() here, put_vudc_device()
+ * calls the platform_device_put()
+ */
platform_device_del(udc_dev->pdev);
put_vudc_device(udc_dev);
}
@@ -89,7 +93,11 @@ static void __exit cleanup(void)

list_for_each_entry_safe(udc_dev, udc_dev2, &vudc_devices, dev_entry) {
list_del(&udc_dev->dev_entry);
- platform_device_unregister(udc_dev->pdev);
+ /*
+ * Just do platform_device_del() here, put_vudc_device()
+ * calls the platform_device_put()
+ */
+ platform_device_del(udc_dev->pdev);
put_vudc_device(udc_dev);
}
platform_driver_unregister(&vudc_driver);