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=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 10BD0C4CEC5 for ; Fri, 13 Sep 2019 13:33:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D890E20717 for ; Fri, 13 Sep 2019 13:33:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568381626; bh=jORffADQrPKKT9/36UIdxIvAdJ5omm4N1b2CQf7U4JQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XdesSa3XnoqgVG0eF3YkH384UmdVvcnxANBltkasEDfHhTmi6hnH+HZLfV50rp3PW PnWtwYkQITu4YsbdkYYYeUzO0yU6V0bi/HrOVmWLdkrUwW2GRKFVBNYReOIbKqe2bC U1INff1mfgLuF918xNei0TO+Qnts1YutRrWCa4xM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391413AbfIMNdm (ORCPT ); Fri, 13 Sep 2019 09:33:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:34510 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388571AbfIMNJs (ORCPT ); Fri, 13 Sep 2019 09:09:48 -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 E05B720CC7; Fri, 13 Sep 2019 13:09:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568380187; bh=jORffADQrPKKT9/36UIdxIvAdJ5omm4N1b2CQf7U4JQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1UbAJjCm0SQRf/INI5nwBM57sgImd5iqI2qlaPL996FC7lBonhgJFBpyJu7BeG4FI V28K0ALoi3Jkn/H/sOnQAqdcMKRrf/j0k0e2/zV7YQzfH3Dksa5BvxIRjuMugwqsum AfC8FKu4xtRKrP1oHXOyODiJujA3Ahl+u8UdNqME= 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 4.9 10/14] batman-adv: Only read OGM tvlv_len after buffer len check Date: Fri, 13 Sep 2019 14:07:03 +0100 Message-Id: <20190913130445.741374686@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190913130440.264749443@linuxfoundation.org> References: <20190913130440.264749443@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: 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 @@ -450,17 +450,23 @@ 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); @@ -488,7 +494,7 @@ 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 */ @@ -1841,7 +1847,7 @@ 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;