From patchwork Tue Sep 8 15:25:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 264232 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 B065BC433E2 for ; Tue, 8 Sep 2020 18:38:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D0602080C for ; Tue, 8 Sep 2020 18:38:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599590310; bh=l5pXDIH58BbziP64ptPqTw2F3wmrA802mD+6ENN3vkg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eYlPtR8PkDbUowo6htt9QzWxSZBBITGMHESPN/B5JH+NYrkb1+EDXaLxWHHT2moDH zxo93FTDOBVoBb85aMKgJpBecjyzFxp1v2A8ev/fs07qgJiD9OhpFAhSTNUMk9Y3TO 5jUffupJNtVH279N+KXAkXU9wVTAYdJhcNujJvbg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731370AbgIHSiW (ORCPT ); Tue, 8 Sep 2020 14:38:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:55372 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731341AbgIHQJA (ORCPT ); Tue, 8 Sep 2020 12:09:00 -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 BE2CC2413B; Tue, 8 Sep 2020 15:49:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599580141; bh=l5pXDIH58BbziP64ptPqTw2F3wmrA802mD+6ENN3vkg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EShjXUOLvLyrI6jqW2CEL+Pi+hh1+5MTPK7EZVYP9Dj2xNA30NtwTQvdMxJDZzZ/n 8K549Cv3kbxpBwQdcR88cS8QEzdTfZtdSwfg5Avy6pRe96PW6T6tOA9tblDQolp6bD sq++b+o3ssRuBQeaa/yuo2fs/MR/dH/k6xGfymZ4= 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 4.19 16/88] batman-adv: Avoid uninitialized chaddr when handling DHCP Date: Tue, 8 Sep 2020 17:25:17 +0200 Message-Id: <20200908152221.888974886@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152221.082184905@linuxfoundation.org> References: <20200908152221.082184905@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 140c61a3f1ecf..0c59fefc13719 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -714,8 +714,10 @@ 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)