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 44492C433EF for ; Mon, 27 Dec 2021 13:11:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233827AbhL0NLA (ORCPT ); Mon, 27 Dec 2021 08:11:00 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:42624 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230148AbhL0NK7 (ORCPT ); Mon, 27 Dec 2021 08:10:59 -0500 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 ams.source.kernel.org (Postfix) with ESMTPS id 4EAD4B80E98 for ; Mon, 27 Dec 2021 13:10:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A764C36AE7; Mon, 27 Dec 2021 13:10:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640610657; bh=Cyn9AN2UpvES1gwjYGXcWJ+8RzG6px/9IXMnMV0Uwjs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZvMyoj+tI0vc+MXK8zxIfyNpKJtfBUlHkpSuKNmbNXWs55BiOotp0O7oTDn3POPmY KQ8WawmPGVQw8ZAR7S8JstipY+KNjcLmO3/uTDLFwhpeaddxIl4t/GQkuvuSTpuMSN GcaWYNx8ulkpqbPAHab4z9ixB/oMU2BrNdEV3maA= Date: Mon, 27 Dec 2021 14:10:54 +0100 From: Greg KH To: Nobuhiro Iwamatsu Cc: stable@vger.kernel.org, sashal@kernel.org, Eddie Hung , Macpaul Lin , Peter Chen Subject: Re: [RFC/PATCH for 4.4.y] usb: gadget: configfs: Fix use-after-free issue with udc_name Message-ID: References: <20211223052626.1631331-1-nobuhiro1.iwamatsu@toshiba.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Dec 27, 2021 at 01:47:35PM +0100, Greg KH wrote: > On Thu, Dec 23, 2021 at 02:26:26PM +0900, Nobuhiro Iwamatsu wrote: > > From: Eddie Hung > > > > commit 64e6bbfff52db4bf6785fab9cffab850b2de6870 upstream. > > > > There is a use-after-free issue, if access udc_name > > in function gadget_dev_desc_UDC_store after another context > > free udc_name in function unregister_gadget. > > > > Context 1: > > gadget_dev_desc_UDC_store()->unregister_gadget()-> > > free udc_name->set udc_name to NULL > > > > Context 2: > > gadget_dev_desc_UDC_show()-> access udc_name > > > > Call trace: > > dump_backtrace+0x0/0x340 > > show_stack+0x14/0x1c > > dump_stack+0xe4/0x134 > > print_address_description+0x78/0x478 > > __kasan_report+0x270/0x2ec > > kasan_report+0x10/0x18 > > __asan_report_load1_noabort+0x18/0x20 > > string+0xf4/0x138 > > vsnprintf+0x428/0x14d0 > > sprintf+0xe4/0x12c > > gadget_dev_desc_UDC_show+0x54/0x64 > > configfs_read_file+0x210/0x3a0 > > __vfs_read+0xf0/0x49c > > vfs_read+0x130/0x2b4 > > SyS_read+0x114/0x208 > > el0_svc_naked+0x34/0x38 > > > > Add mutex_lock to protect this kind of scenario. > > > > Signed-off-by: Eddie Hung > > Signed-off-by: Macpaul Lin > > Reviewed-by: Peter Chen > > Cc: stable@vger.kernel.org > > Link: https://lore.kernel.org/r/1609239215-21819-1-git-send-email-macpaul.lin@mediatek.com > > Signed-off-by: Greg Kroah-Hartman > > [Reference: CVE-2021-39648] > > [iwamatsu: struct usb_gadget_driver does not have udc_name variable. > > Change struct gadget_info's udc_name.] > > Signed-off-by: Nobuhiro Iwamatsu (CIP) > > --- > > drivers/usb/gadget/configfs.c | 11 ++++++++++- > > 1 file changed, 10 insertions(+), 1 deletion(-) > > Now queued up, thanks. > > greg k-h Oops, nope, this gives me a build warning, something is wrong with this change: CC [M] drivers/usb/gadget/configfs.o drivers/usb/gadget/configfs.c: In function ‘gadget_dev_desc_UDC_show’: drivers/usb/gadget/configfs.c:249:18: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers] 249 | udc_name = gi->udc_name; | ^ Please always test-build your patches :( thanks, greg k-h