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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 1318EC10F11 for ; Wed, 24 Apr 2019 09:52:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1DA32148D for ; Wed, 24 Apr 2019 09:52:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="GqThel/Z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727777AbfDXJwi (ORCPT ); Wed, 24 Apr 2019 05:52:38 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:48310 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726216AbfDXJwh (ORCPT ); Wed, 24 Apr 2019 05:52:37 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3O9nUP3031264; Wed, 24 Apr 2019 09:52:31 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type; s=corp-2018-07-02; bh=9xUAQynxxcopPBpkyEnnXya3Rm/3GMgYNaN5Wfhwjy0=; b=GqThel/ZcjVtCCnNvnmEKKru9v/DL+7TZmc6FUNvrdyDyC48wh+39aCC30844d8jMqd/ K9mkeW/mfrBNplPd9pcqUkQiYI767P8kiJMfpcEwketYa5ueUT7KG06wHIXcDam+snjw 67RbYqw2JtFYUpvJsc8W1tPF/a7IEEWpr3j2vSv5bmXbZ2yQBztwR1NQu+2dwlkCcxfJ 0eBe+Csq0NdjgjVeyndGOJvA/FcpeGLkHo1JwdqPVCewvWvie53OAqTjtXuCSRmAepql Uzn8CfLo6Psy0wb/a9OXTdTO0HozJmf4XGY4/fUNVh4RlklgtG0zT0fe6VixNIL8aN5l /Q== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by aserp2130.oracle.com with ESMTP id 2ryrxd1fnn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 24 Apr 2019 09:52:31 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3O9qRhO161590; Wed, 24 Apr 2019 09:52:31 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 2s0f0w084q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 24 Apr 2019 09:52:30 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x3O9qTeW002902; Wed, 24 Apr 2019 09:52:29 GMT Received: from mwanda (/105.55.12.114) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 24 Apr 2019 02:52:28 -0700 Date: Wed, 24 Apr 2019 12:52:18 +0300 From: Dan Carpenter To: Arend van Spriel Cc: Franky Lin , Hante Meuleman , Chi-Hsien Lin , Wright Feng , Kalle Valo , linux-wireless@vger.kernel.org, brcm80211-dev-list.pdl@broadcom.com, brcm80211-dev-list@cypress.com, kernel-janitors@vger.kernel.org Subject: [PATCH] brcm80211: potential NULL dereference in brcmf_cfg80211_vndr_cmds_dcmd_handler() Message-ID: <20190424095218.GB16450@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailer: git-send-email haha only kidding User-Agent: Mutt/1.10.1 (2018-07-13) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9236 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904240083 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9236 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-1904240083 Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org If "ret_len" is negative then it could lead to a NULL dereference. The "ret_len" value comes from nl80211_vendor_cmd(), if it's negative then we don't allocate the "dcmd_buf" buffer. Then we pass "ret_len" to brcmf_fil_cmd_data_set() where it is cast to a very high u32 value. Most of the functions in that call tree check whether the buffer we pass is NULL but there are at least a couple places which don't such as brcmf_dbg_hex_dump() and brcmf_msgbuf_query_dcmd(). We memcpy() to and from the buffer so it would result in a NULL dereference. The fix is to change the types so that "ret_len" can't be negative. (If we memcpy() zero bytes to NULL, that's a no-op and doesn't cause an issue). Fixes: 1bacb0487d0e ("brcmfmac: replace cfg80211 testmode with vendor command") Signed-off-by: Dan Carpenter --- drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c index 8eff2753abad..d493021f6031 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c @@ -35,9 +35,10 @@ static int brcmf_cfg80211_vndr_cmds_dcmd_handler(struct wiphy *wiphy, struct brcmf_if *ifp; const struct brcmf_vndr_dcmd_hdr *cmdhdr = data; struct sk_buff *reply; - int ret, payload, ret_len; + unsigned int payload, ret_len; void *dcmd_buf = NULL, *wr_pointer; u16 msglen, maxmsglen = PAGE_SIZE - 0x100; + int ret; if (len < sizeof(*cmdhdr)) { brcmf_err("vendor command too short: %d\n", len); @@ -65,7 +66,7 @@ static int brcmf_cfg80211_vndr_cmds_dcmd_handler(struct wiphy *wiphy, brcmf_err("oversize return buffer %d\n", ret_len); ret_len = BRCMF_DCMD_MAXLEN; } - payload = max(ret_len, len) + 1; + payload = max_t(unsigned int, ret_len, len) + 1; dcmd_buf = vzalloc(payload); if (NULL == dcmd_buf) return -ENOMEM; -- 2.18.0