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=-7.0 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=unavailable 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 90399C49ED7 for ; Fri, 13 Sep 2019 13:23:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69C6A2189D for ; Fri, 13 Sep 2019 13:23:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568381013; bh=Zop4+s4luVAimXt+InNTc/XmzvttpS21f21hxI/OF6I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VG+0OvNVYnm/RseoZJ9S9V8goD5s20/oL5dBvU1wRCCi5LqbScFQTBazt3Js1Lj1y VNm/L1kvxjO04oEZL6IGosR12OvDmob3tJ3w/DsbWDLJahlFHTkjB8Tkgl0Y6KpmS0 A+SLBOct/k2fyFt736RacJ5+zfZNy4l2QaRu9+sY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390744AbfIMNVK (ORCPT ); Fri, 13 Sep 2019 09:21:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:50644 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390755AbfIMNVK (ORCPT ); Fri, 13 Sep 2019 09:21:10 -0400 Received: from localhost (unknown [104.132.45.99]) (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 2C930214DA; Fri, 13 Sep 2019 13:21:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568380869; bh=Zop4+s4luVAimXt+InNTc/XmzvttpS21f21hxI/OF6I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y2fiHs07SZOusPQUubc9hgC+uyrAEVNAa5nUkrZxwPB31IOAOSSMMxrIoNc3rqZ4T ZepcUCWeKN4WD0VbNRK+VXQ88C0qNOg6ib3Kwo+y8inrh49df+W75k0Sbo1JzBhdeO mDOIbXORkzRdef3+9wwP3svqmcU1/v6WYZmE4kZI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+355cab184197dbbfa384@syzkaller.appspotmail.com, Sven Eckelmann , Antonio Quartulli , Simon Wunderlich Subject: [PATCH 5.2 17/37] batman-adv: Only read OGM tvlv_len after buffer len check Date: Fri, 13 Sep 2019 14:07:22 +0100 Message-Id: <20190913130518.242128562@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190913130510.727515099@linuxfoundation.org> References: <20190913130510.727515099@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sven Eckelmann commit a15d56a60760aa9dbe26343b9a0ac5228f35d445 upstream. Multiple batadv_ogm_packet can be stored in an skbuff. The functions batadv_iv_ogm_send_to_if()/batadv_iv_ogm_receive() use batadv_iv_ogm_aggr_packet() to check if there is another additional batadv_ogm_packet in the skb or not before they continue processing the packet. The length for such an OGM is BATADV_OGM_HLEN + batadv_ogm_packet->tvlv_len. The check must first check that at least BATADV_OGM_HLEN bytes are available before it accesses tvlv_len (which is part of the header. Otherwise it might try read outside of the currently available skbuff to get the content of tvlv_len. Fixes: ef26157747d4 ("batman-adv: tvlv - basic infrastructure") Reported-by: syzbot+355cab184197dbbfa384@syzkaller.appspotmail.com Signed-off-by: Sven Eckelmann Acked-by: Antonio Quartulli Signed-off-by: Simon Wunderlich Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/bat_iv_ogm.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) --- a/net/batman-adv/bat_iv_ogm.c +++ b/net/batman-adv/bat_iv_ogm.c @@ -277,17 +277,23 @@ static u8 batadv_hop_penalty(u8 tq, cons * batadv_iv_ogm_aggr_packet() - checks if there is another OGM attached * @buff_pos: current position in the skb * @packet_len: total length of the skb - * @tvlv_len: tvlv length of the previously considered OGM + * @ogm_packet: potential OGM in buffer * * Return: true if there is enough space for another OGM, false otherwise. */ -static bool batadv_iv_ogm_aggr_packet(int buff_pos, int packet_len, - __be16 tvlv_len) +static bool +batadv_iv_ogm_aggr_packet(int buff_pos, int packet_len, + const struct batadv_ogm_packet *ogm_packet) { int next_buff_pos = 0; - next_buff_pos += buff_pos + BATADV_OGM_HLEN; - next_buff_pos += ntohs(tvlv_len); + /* check if there is enough space for the header */ + next_buff_pos += buff_pos + sizeof(*ogm_packet); + if (next_buff_pos > packet_len) + return false; + + /* check if there is enough space for the optional TVLV */ + next_buff_pos += ntohs(ogm_packet->tvlv_len); return (next_buff_pos <= packet_len) && (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES); @@ -315,7 +321,7 @@ static void batadv_iv_ogm_send_to_if(str /* adjust all flags and log packets */ while (batadv_iv_ogm_aggr_packet(buff_pos, forw_packet->packet_len, - batadv_ogm_packet->tvlv_len)) { + batadv_ogm_packet)) { /* we might have aggregated direct link packets with an * ordinary base packet */ @@ -1704,7 +1710,7 @@ static int batadv_iv_ogm_receive(struct /* unpack the aggregated packets and process them one by one */ while (batadv_iv_ogm_aggr_packet(ogm_offset, skb_headlen(skb), - ogm_packet->tvlv_len)) { + ogm_packet)) { batadv_iv_ogm_process(skb, ogm_offset, if_incoming); ogm_offset += BATADV_OGM_HLEN;