From patchwork Tue Sep 8 15:25:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 310033 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=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 9E67CC43461 for ; Tue, 8 Sep 2020 18:04:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F75921D46 for ; Tue, 8 Sep 2020 18:04:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599588285; bh=oszbqs7PEBghjGCl+rJ3kmEUWpwsIgRPGgvaQAx0z2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PxS6duwoCZXs3CZ2D6V03DTlW3a36TuFWPdVROaW/hnVsUd1jt2JyjtgfmEKsm9D7 9lYh8hHFZpvJ1CuDj30f6G/GaaosuhLkAp8KMkq/rXyfd61tQcTvo6ufLI5Q5K2A72 Xfn4aoNzMhGYil93zMzSi5t7oHma9lBNZ4tsQ+kE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732056AbgIHSEm (ORCPT ); Tue, 8 Sep 2020 14:04:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:56084 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731519AbgIHQMK (ORCPT ); Tue, 8 Sep 2020 12:12:10 -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 1EE4E2478F; Tue, 8 Sep 2020 15:51:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599580279; bh=oszbqs7PEBghjGCl+rJ3kmEUWpwsIgRPGgvaQAx0z2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ox286CfTG3JhqcfLgHnKI423JgvxtEtyu6fYRagF4ILGOWo/qrwR08LIn+a5Uh3aP AW3sMHk9w2ol9IO9E/f8potJH4rZQZmLvV7WVqUhWAWs13oNRIyObwRPZAEQKDlMxH kQvP1eV2hS1AgnDTmBk3ABDLLSi589SO9w+ELXSI= 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 4.14 12/65] batman-adv: Avoid uninitialized chaddr when handling DHCP Date: Tue, 8 Sep 2020 17:25:57 +0200 Message-Id: <20200908152217.659257918@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152217.022816723@linuxfoundation.org> References: <20200908152217.022816723@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 c6a7341f05270..056af2eec4a2a 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -674,8 +674,10 @@ 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)