USB: cdc-acm: fix use-after-free after probe failure

BugLink: https://bugs.launchpad.net/bugs/1923869
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@vger.kernel.org      # 3.9
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210322155318.9837-3-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 3231f571c6469532417e31e1fdc9e70e69044571..9cc6318ca4425374d936c18459e4dd71d2e1a044 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1529,6 +1529,11 @@ 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);