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[v2,2/8] USB: cdc-acm: fix use-after-free after probe failure

Message ID 20210322155318.9837-3-johan@kernel.org
State New
Headers show
Series USB: cdc-acm: probe fixes | expand

Commit Message

Johan Hovold March 22, 2021, 3:53 p.m. UTC
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>
---
 drivers/usb/class/cdc-acm.c | 5 +++++
 1 file changed, 5 insertions(+)
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Patch

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index d75a78ad464d..dfc2480add91 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1503,6 +1503,11 @@  static int acm_probe(struct usb_interface *intf,
 
 	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);