usb: ucsi: Fix NULL pointer deref in ucsi_connector_change()

When ucsi_init() fails, ucsi->connector is NULL, yet in case of
ucsi_acpi we may still get events which cause the ucs_acpi code to call
ucsi_connector_change(), which then derefs the NULL ucsi->connector
pointer.

Fix this by not setting ucsi->ntfy inside ucsi_init() until ucsi_init()
has succeeded, so that ucsi_connector_change() ignores the events
because UCSI_ENABLE_NTFY_CONNECTOR_CHANGE is not set in the ntfy mask.

Fixes: bdc62f2 ("usb: typec: ucsi: Simplified registration and I/O API")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217106
Cc: stable@vger.kernel.org
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230308154244.722337-2-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: jwrdegoede

drivers/usb/typec/ucsi/ucsi.c

@@ -1329,7 +1329,7 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
 static int ucsi_init(struct ucsi *ucsi)
 {
 	struct ucsi_connector *con;
-	u64 command;
+	u64 command, ntfy;
 	int ret;
 	int i;
 
@@ -1341,8 +1341,8 @@ static int ucsi_init(struct ucsi *ucsi)
 	}
 
 	/* Enable basic notifications */
-	ucsi->ntfy = UCSI_ENABLE_NTFY_CMD_COMPLETE | UCSI_ENABLE_NTFY_ERROR;
-	command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy;
+	ntfy = UCSI_ENABLE_NTFY_CMD_COMPLETE | UCSI_ENABLE_NTFY_ERROR;
+	command = UCSI_SET_NOTIFICATION_ENABLE | ntfy;
 	ret = ucsi_send_command(ucsi, command, NULL, 0);
 	if (ret < 0)
 		goto err_reset;
@@ -1374,12 +1374,13 @@ static int ucsi_init(struct ucsi *ucsi)
 	}
 
 	/* Enable all notifications */
-	ucsi->ntfy = UCSI_ENABLE_NTFY_ALL;
-	command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy;
+	ntfy = UCSI_ENABLE_NTFY_ALL;
+	command = UCSI_SET_NOTIFICATION_ENABLE | ntfy;
 	ret = ucsi_send_command(ucsi, command, NULL, 0);
 	if (ret < 0)
 		goto err_unregister;
 
+	ucsi->ntfy = ntfy;
 	return 0;
 
 err_unregister: