From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C09C1E489; Mon, 21 Jul 2025 05:39:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753076356; cv=none; b=YsDDC9QL5C4TMpqTjWvjnFOGvEDA5udpyk2aPyjRVqRWgV5L6hiocXUcuLgsxjOPMopbkrTFQvER6l/R6TeRwFOEOkqsyBcxLj6YhHWKdNePYO2y1ZJLLQuEeXxjzNHBUF5DfofhQc1F+2WP0Y2T+tiG6U8/44+P2hCLe1djLGo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753076356; c=relaxed/simple; bh=IzjSet9jg6pPQtROJFXhSSwZmbVirJFjosi+fTcj+VY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YdUDaZov1oM+IivJrBNcM1MTnHkoFAGcbpchrE0/sgsMB0Za63yOmwZdCbfvqyrZPOp5XvKJM0ymuiNsH3lcovtTVXG8n+SGmPNx3ncN23M6OM0Ot52JI1njTUeV3wqpAfS4YhbjIfBdy0loJbLt8RLRc4HeoaO6AtdHXDaFGCo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TvT+ZUze; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TvT+ZUze" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BD03C4CEF1; Mon, 21 Jul 2025 05:39:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1753076355; bh=IzjSet9jg6pPQtROJFXhSSwZmbVirJFjosi+fTcj+VY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TvT+ZUzeKAiWxGbFyrZ//e+ucHLsFvGU0K50RrJGmnYamDc1SMMjyw3LxoAqgMCxK +31Fs8shuABGeq4UFrulyFTliakeY8X/rCV4zytFCD5h67W2LweNu/UNMwNDuD79WH e1BX1Ob14B7Be5x09jdy7o0Y0lrWXik4707FuqVA= Date: Mon, 21 Jul 2025 07:39:11 +0200 From: Greg KH To: Tao Xue Cc: Thinh.Nguyen@synopsys.com, prashanth.k@oss.qualcomm.com, m.grzeschik@pengutronix.de, Chris.Wulff@biamp.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, caiyadong@huawei.com, suzhuangluan@hisilicon.com, weiwenwen3@huawei.com Subject: Re: [PATCH v2] usb: gadget : fix use-after-free in composite_dev_cleanup() Message-ID: <2025072150-unfunded-washable-b524@gregkh> References: <20250721035849.11330-1-xuetao09@huawei.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250721035849.11330-1-xuetao09@huawei.com> On Mon, Jul 21, 2025 at 11:58:49AM +0800, Tao Xue wrote: > 1. In func configfs_composite_bind() -> composite_os_desc_req_prepare(): > if kmalloc fails, the pointer cdev->os_desc_req will be freed but not > set to NULL. Then it will return a failure to the upper-level function. > 2. in func configfs_composite_bind() -> composite_dev_cleanup(): > it will checks whether cdev->os_desc_req is NULL. If it is not NULL, it > will attempt to use it.This will lead to a use-after-free issue. > > BUG: KASAN: use-after-free in composite_dev_cleanup+0xf4/0x2c0 > Read of size 8 at addr 0000004827837a00 by task init/1 > > CPU: 10 PID: 1 Comm: init Tainted: G O 5.10.97-oh #1 > kasan_report+0x188/0x1cc > __asan_load8+0xb4/0xbc > composite_dev_cleanup+0xf4/0x2c0 > configfs_composite_bind+0x210/0x7ac > udc_bind_to_driver+0xb4/0x1ec > usb_gadget_probe_driver+0xec/0x21c > gadget_dev_desc_UDC_store+0x264/0x27c > > Fixes: 37a3a533429e ("usb: gadget: OS Feature Descriptors support") > Signed-off-by: Tao Xue > --- > v2: update Signed-off and commit message > v1: initial submission > > drivers/usb/gadget/composite.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c > index 8dbc132a505e..385398a039ea 100644 > --- a/drivers/usb/gadget/composite.c > +++ b/drivers/usb/gadget/composite.c > @@ -2489,6 +2489,7 @@ int composite_os_desc_req_prepare(struct usb_composite_dev *cdev, > if (!cdev->os_desc_req->buf) { > ret = -ENOMEM; > usb_ep_free_request(ep0, cdev->os_desc_req); > + cdev->os_desc_req = NULL; Please add a comment here as to why this must be set to NULL at this point in time, as it is not obvious at all. thanks, greg k-h