[PATCH 4.19 51/56] USB: cdc-acm: fix use-after-free after probe failure

From: Greg Kroah-Hartman
Date: Mon Apr 05 2021 - 05:03:20 EST


From: Johan Hovold <johan@xxxxxxxxxx>

commit 4e49bf376c0451ad2eae2592e093659cde12be9a upstream.

If tty-device registration fails the driver would fail to release the
data interface. When the device is later disconnected, the disconnect
callback would still be called for the data interface and would go about
releasing already freed resources.

Fixes: c93d81955005 ("usb: cdc-acm: fix error handling in acm_probe()")
Cc: stable@xxxxxxxxxxxxxxx # 3.9
Cc: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Acked-by: Oliver Neukum <oneukum@xxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210322155318.9837-3-johan@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/class/cdc-acm.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1561,6 +1561,11 @@ skip_countries:

return 0;
alloc_fail6:
+ if (!acm->combined_interfaces) {
+ /* Clear driver data so that disconnect() returns early. */
+ usb_set_intfdata(data_interface, NULL);
+ usb_driver_release_interface(&acm_driver, data_interface);
+ }
if (acm->country_codes) {
device_remove_file(&acm->control->dev,
&dev_attr_wCountryCodes);