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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 0808BC4360C for ; Thu, 10 Oct 2019 08:49:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D2D4922790 for ; Thu, 10 Oct 2019 08:49:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570697370; bh=7tld6r4njYlcCBmeGgYzIQgVbZE6ybfWh0j0vccDjpc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kBi/qn7nMWiFUHpm5c+970Z9KxjPdlDvTDrZSsrzxEwiWHUhc1CkcSPaSX/zYe273 sP54i1P/VajmrDkc3MscpC04B9zipzKiol5tZ+T7HDUe55HdZU79O/gn/o026EGM1d MJdoC6F30YHxDQ4q/QuJPKkbfEkVpxCYxbHJmUwQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388397AbfJJIta (ORCPT ); Thu, 10 Oct 2019 04:49:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:56012 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389279AbfJJItZ (ORCPT ); Thu, 10 Oct 2019 04:49:25 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6DA58218AC; Thu, 10 Oct 2019 08:49:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570697365; bh=7tld6r4njYlcCBmeGgYzIQgVbZE6ybfWh0j0vccDjpc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0a/7PuSsFODGKQKHov/uq4EyH8cC0U6sDB3h+ND6ee2FnAPmskWBpJR0+2ycPCFWA wVbNOZojkCGYgW8tHxI4MDMe6FLgd+dYOJbnTiEa5Xz74nfman2JFYWV2kSocTMYrf uJe/GOKiDdF2Ezscf/6sUCJjndzL6U1w7cdvXTdA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Berg Subject: [PATCH 4.19 114/114] nl80211: validate beacon head Date: Thu, 10 Oct 2019 10:37:01 +0200 Message-Id: <20191010083614.334354467@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191010083544.711104709@linuxfoundation.org> References: <20191010083544.711104709@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johannes Berg commit f88eb7c0d002a67ef31aeb7850b42ff69abc46dc upstream. We currently don't validate the beacon head, i.e. the header, fixed part and elements that are to go in front of the TIM element. This means that the variable elements there can be malformed, e.g. have a length exceeding the buffer size, but most downstream code from this assumes that this has already been checked. Add the necessary checks to the netlink policy. Cc: stable@vger.kernel.org Fixes: ed1b6cc7f80f ("cfg80211/nl80211: add beacon settings") Link: https://lore.kernel.org/r/1569009255-I7ac7fbe9436e9d8733439eab8acbbd35e55c74ef@changeid Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/wireless/nl80211.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -200,6 +200,38 @@ cfg80211_get_dev_from_info(struct net *n return __cfg80211_rdev_from_attrs(netns, info->attrs); } +static int validate_beacon_head(const struct nlattr *attr, + struct netlink_ext_ack *extack) +{ + const u8 *data = nla_data(attr); + unsigned int len = nla_len(attr); + const struct element *elem; + const struct ieee80211_mgmt *mgmt = (void *)data; + unsigned int fixedlen = offsetof(struct ieee80211_mgmt, + u.beacon.variable); + + if (len < fixedlen) + goto err; + + if (ieee80211_hdrlen(mgmt->frame_control) != + offsetof(struct ieee80211_mgmt, u.beacon)) + goto err; + + data += fixedlen; + len -= fixedlen; + + for_each_element(elem, data, len) { + /* nothing */ + } + + if (for_each_element_completed(elem, data, len)) + return 0; + +err: + NL_SET_ERR_MSG_ATTR(extack, attr, "malformed beacon head"); + return -EINVAL; +} + /* policy for the attributes */ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = { [NL80211_ATTR_WIPHY] = { .type = NLA_U32 }, @@ -4016,6 +4048,12 @@ static int nl80211_parse_beacon(struct n memset(bcn, 0, sizeof(*bcn)); if (attrs[NL80211_ATTR_BEACON_HEAD]) { + int ret = validate_beacon_head(attrs[NL80211_ATTR_BEACON_HEAD], + NULL); + + if (ret) + return ret; + bcn->head = nla_data(attrs[NL80211_ATTR_BEACON_HEAD]); bcn->head_len = nla_len(attrs[NL80211_ATTR_BEACON_HEAD]); if (!bcn->head_len)