From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE010C43334 for ; Mon, 27 Jun 2022 11:42:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236953AbiF0LmA (ORCPT ); Mon, 27 Jun 2022 07:42:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236590AbiF0Lin (ORCPT ); Mon, 27 Jun 2022 07:38:43 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1E945BCB6; Mon, 27 Jun 2022 04:35:06 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id ADEBC60DBD; Mon, 27 Jun 2022 11:35:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9193C341C7; Mon, 27 Jun 2022 11:35:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656329705; bh=wkT9UHQRmlllcIk11aMHmLKWq0J84Omjdf8rIqTp0J4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2RipE7/re72EFO97xCLXEq1batdG6vjXjGr1xvK2F17dU/nru/HwXSAxKXRtj+h9d C52ovEwHbZODHkZo6wd2EaTH4Atmk/tOz7JPyJbcyWsgoOojFl0BeXQxMCJmi+xq3o gp46lRDp3Sxv5hU3Ld/cYCOlFt0RBfaF6nMAMEZM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrey Konovalov , Alan Stern Subject: [PATCH 5.15 088/135] USB: gadget: Fix double-free bug in raw_gadget driver Date: Mon, 27 Jun 2022 13:21:35 +0200 Message-Id: <20220627111940.712994645@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220627111938.151743692@linuxfoundation.org> References: <20220627111938.151743692@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alan Stern commit 90bc2af24638659da56397ff835f3c95a948f991 upstream. Re-reading a recently merged fix to the raw_gadget driver showed that it inadvertently introduced a double-free bug in a failure pathway. If raw_ioctl_init() encounters an error after the driver ID number has been allocated, it deallocates the ID number before returning. But when dev_free() runs later on, it will then try to deallocate the ID number a second time. Closely related to this issue is another error in the recent fix: The ID number is stored in the raw_dev structure before the code checks to see whether the structure has already been initialized, in which case the new ID number would overwrite the earlier value. The solution to both bugs is to keep the new ID number in a local variable, and store it in the raw_dev structure only after the check for prior initialization. No errors can occur after that point, so the double-free will never happen. Fixes: f2d8c2606825 ("usb: gadget: Fix non-unique driver names in raw-gadget driver") CC: Andrey Konovalov CC: Signed-off-by: Alan Stern Link: https://lore.kernel.org/r/YrMrRw5AyIZghN0v@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/legacy/raw_gadget.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/drivers/usb/gadget/legacy/raw_gadget.c +++ b/drivers/usb/gadget/legacy/raw_gadget.c @@ -430,6 +430,7 @@ out_put: static int raw_ioctl_init(struct raw_dev *dev, unsigned long value) { int ret = 0; + int driver_id_number; struct usb_raw_init arg; char *udc_driver_name; char *udc_device_name; @@ -452,10 +453,9 @@ static int raw_ioctl_init(struct raw_dev return -EINVAL; } - ret = ida_alloc(&driver_id_numbers, GFP_KERNEL); - if (ret < 0) - return ret; - dev->driver_id_number = ret; + driver_id_number = ida_alloc(&driver_id_numbers, GFP_KERNEL); + if (driver_id_number < 0) + return driver_id_number; driver_driver_name = kmalloc(DRIVER_DRIVER_NAME_LENGTH_MAX, GFP_KERNEL); if (!driver_driver_name) { @@ -463,7 +463,7 @@ static int raw_ioctl_init(struct raw_dev goto out_free_driver_id_number; } snprintf(driver_driver_name, DRIVER_DRIVER_NAME_LENGTH_MAX, - DRIVER_NAME ".%d", dev->driver_id_number); + DRIVER_NAME ".%d", driver_id_number); udc_driver_name = kmalloc(UDC_NAME_LENGTH_MAX, GFP_KERNEL); if (!udc_driver_name) { @@ -507,6 +507,7 @@ static int raw_ioctl_init(struct raw_dev dev->driver.driver.name = driver_driver_name; dev->driver.udc_name = udc_device_name; dev->driver.match_existing_only = 1; + dev->driver_id_number = driver_id_number; dev->state = STATE_DEV_INITIALIZED; spin_unlock_irqrestore(&dev->lock, flags); @@ -521,7 +522,7 @@ out_free_udc_driver_name: out_free_driver_driver_name: kfree(driver_driver_name); out_free_driver_id_number: - ida_free(&driver_id_numbers, dev->driver_id_number); + ida_free(&driver_id_numbers, driver_id_number); return ret; }