From patchwork Fri Sep 11 12:45:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 309767 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, 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 F085CC43461 for ; Fri, 11 Sep 2020 17:36:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A765D221EF for ; Fri, 11 Sep 2020 17:36:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599845817; bh=DFDRKke5vROvEQcUa5OL+LpykKysm/Lz5k45FUhZR8M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aN5u93xuKHnldPXPo2Amj2APqzTCv3el48coi36jGZ0xmmoywnMA3CaXVdthUFRTt cz5j2RHdzCe5Mv6ZDjgk48j95uzsX+mDey0bSnciCidxdVxSdJ/8P8XHeJTT89sOFd GEKJ+orqBnGK8e3tb+T69IBwylI0SeL/lsXz86g0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726351AbgIKRgO (ORCPT ); Fri, 11 Sep 2020 13:36:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:48356 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725928AbgIKMxc (ORCPT ); Fri, 11 Sep 2020 08:53:32 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 A1472221E3; Fri, 11 Sep 2020 12:53:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599828796; bh=DFDRKke5vROvEQcUa5OL+LpykKysm/Lz5k45FUhZR8M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nUMMaZYmOP/zlfAFQdlBCZSkzAkZGT5HpekTHrrStYnozoeelK3pWW3ZyFDZtHChS OXZ/yMvXVEqlco6SnHvAgsbKzx3gKa6a41VMRygWEFcElciK8z9PzCl+6YOM4rpiLL AV6HJLLvCWz1QuShi+Fe9X6My9N4gTan4N2eZT9g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+ab16e463b903f5a37036@syzkaller.appspotmail.com, Sven Eckelmann , Antonio Quartulli , Simon Wunderlich , Sasha Levin Subject: [PATCH 4.4 10/62] batman-adv: Avoid uninitialized chaddr when handling DHCP Date: Fri, 11 Sep 2020 14:45:53 +0200 Message-Id: <20200911122502.905848423@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200911122502.395450276@linuxfoundation.org> References: <20200911122502.395450276@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sven Eckelmann [ Upstream commit 303216e76dcab6049c9d42390b1032f0649a8206 ] The gateway client code can try to optimize the delivery of DHCP packets to avoid broadcasting them through the whole mesh. But also transmissions to the client can be optimized by looking up the destination via the chaddr of the DHCP packet. But the chaddr is currently only done when chaddr is fully inside the non-paged area of the skbuff. Otherwise it will not be initialized and the unoptimized path should have been taken. But the implementation didn't handle this correctly. It didn't retrieve the correct chaddr but still tried to perform the TT lookup with this uninitialized memory. Reported-by: syzbot+ab16e463b903f5a37036@syzkaller.appspotmail.com Fixes: 6c413b1c22a2 ("batman-adv: send every DHCP packet as bat-unicast") Signed-off-by: Sven Eckelmann Acked-by: Antonio Quartulli Signed-off-by: Simon Wunderlich Signed-off-by: Sasha Levin --- net/batman-adv/gateway_client.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index a88b529b7ca08..5fdb88f72b68f 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -757,8 +757,10 @@ batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len, chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET; /* store the client address if the message is going to a client */ - if (ret == BATADV_DHCP_TO_CLIENT && - pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) { + if (ret == BATADV_DHCP_TO_CLIENT) { + if (!pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) + return BATADV_DHCP_NO; + /* check if the DHCP packet carries an Ethernet DHCP */ p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET; if (*p != BATADV_DHCP_HTYPE_ETHERNET)