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 X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 590AAC43381 for ; Wed, 20 Mar 2019 08:59:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D1702175B for ; Wed, 20 Mar 2019 08:59:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Yuy2FPOt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726780AbfCTI7L (ORCPT ); Wed, 20 Mar 2019 04:59:11 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:39508 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725905AbfCTI7L (ORCPT ); Wed, 20 Mar 2019 04:59:11 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x2K8sLHn149988; Wed, 20 Mar 2019 08:59:03 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=Mq3oeKvwEtgfjFSKPpK1HBygoHwQWpAO8dOx1N18U1s=; b=Yuy2FPOtlegvvJIcWXGkEJyBlj8fylOF7oJqPBDI4H+Mchy+YFzYN0CuoAO4P+OWNsSq NIh8NS2570kECwTxWbVZITQ46wIw7fGc+RRXfnw3gE8XGt0X8GPxVq+lhTfmPfkUekpj o9zeShwC21X0DBwSZUNSetKMRaPfoTbUOsykB6FzplKbfJSUHo00z/CiMTBOQVJNrEQ0 o3e8c8/thpn8rSqdCsWZJ6dznJjis10/rSCKeCEy15AXIfZnvYGK3Cl4KURqudrMPMk2 YRr+i3g8uARvuG6vk6f6ZpMx1pSCoXHf5JyqQYjE5jjjCr9SWdXmbMLwb0VXglqizKft +Q== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2120.oracle.com with ESMTP id 2r8ssrhc88-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Mar 2019 08:59:03 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x2K8x2vH011728 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Mar 2019 08:59:02 GMT Received: from abhmp0020.oracle.com (abhmp0020.oracle.com [141.146.116.26]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x2K8x1n6001887; Wed, 20 Mar 2019 08:59:01 GMT Received: from kadam (/10.175.25.169) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 20 Mar 2019 01:59:01 -0700 Date: Wed, 20 Mar 2019 11:58:59 +0300 From: Dan Carpenter To: Colin Ian King Cc: Larry Finger , "devel@driverdev.osuosl.org" , "linux-kernel@vger.kernel.org" Subject: Re: static analysis bug report: staging r8712u memcpy of uninitialized variable Message-ID: <20190320085858.GF2202@kadam> References: <2b54dc2d-7509-dc76-b730-4c8d66f81226@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2b54dc2d-7509-dc76-b730-4c8d66f81226@canonical.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9200 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903200074 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 18, 2019 at 11:20:51AM +0000, Colin Ian King wrote: > Hi, > > Static analysis with cppcheck found a couple of interesting issues with > memcpy'ing of an uninitialized variable. Two occurrences of the same > issue are found in drivers/staging/rtl8712/rtl8712_cmd.c in functions > read_bbreg_hdl and read_rfreg_hdl. > > For example: > > static u8 read_bbreg_hdl(struct _adapter *padapter, u8 *pbuf) > { > u32 val; > void (*pcmd_callback)(struct _adapter *dev, struct cmd_obj > *pcmd); > struct cmd_obj *pcmd = (struct cmd_obj *)pbuf; > > if (pcmd->rsp && pcmd->rspsz > 0) > memcpy(pcmd->rsp, (u8 *)&val, pcmd->rspsz); > > .... > > } > > I don't understand why the contents of val is being memcpy'd to > pcmd->rsp, especially when val is uninitialized and hence contains > garbage. Any ideas? > The concern would be that it's reading a user specified amount of stack memory to pcmd->rsp and that sounds like an information leak. The pcmd_callback function pointer is always r8712_getbbrfreg_cmdrsp_callback() which frees pcmd->parmbuf and pcmd but leaks pcmd->rsp. I don't see a way for anyone to access the ->rsp memory so probably there aren't any security implications. Anyway, let me send a patch. regards, dan carpenter