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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 7C596ECDFBB for ; Fri, 20 Jul 2018 12:28:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42F2620857 for ; Fri, 20 Jul 2018 12:28:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42F2620857 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387928AbeGTNQD (ORCPT ); Fri, 20 Jul 2018 09:16:03 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35910 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731878AbeGTNQC (ORCPT ); Fri, 20 Jul 2018 09:16:02 -0400 Received: from localhost (LFbn-1-12238-233.w90-92.abo.wanadoo.fr [90.92.53.233]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id AFD7ABCF; Fri, 20 Jul 2018 12:28:01 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+2b43f681169a2a0d306a@syzkaller.appspotmail.com, Florian Westphal , Pablo Neira Ayuso Subject: [PATCH 4.4 28/31] netfilter: ebtables: reject non-bridge targets Date: Fri, 20 Jul 2018 14:13:58 +0200 Message-Id: <20180720121341.171183780@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180720121340.158484922@linuxfoundation.org> References: <20180720121340.158484922@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal commit 11ff7288beb2b7da889a014aff0a7b80bf8efcf3 upstream. the ebtables evaluation loop expects targets to return positive values (jumps), or negative values (absolute verdicts). This is completely different from what xtables does. In xtables, targets are expected to return the standard netfilter verdicts, i.e. NF_DROP, NF_ACCEPT, etc. ebtables will consider these as jumps. Therefore reject any target found due to unspec fallback. v2: also reject watchers. ebtables ignores their return value, so a target that assumes skb ownership (and returns NF_STOLEN) causes use-after-free. The only watchers in the 'ebtables' front-end are log and nflog; both have AF_BRIDGE specific wrappers on kernel side. Reported-by: syzbot+2b43f681169a2a0d306a@syzkaller.appspotmail.com Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/bridge/netfilter/ebtables.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -404,6 +404,12 @@ ebt_check_watcher(struct ebt_entry_watch watcher = xt_request_find_target(NFPROTO_BRIDGE, w->u.name, 0); if (IS_ERR(watcher)) return PTR_ERR(watcher); + + if (watcher->family != NFPROTO_BRIDGE) { + module_put(watcher->me); + return -ENOENT; + } + w->u.watcher = watcher; par->target = watcher; @@ -724,6 +730,13 @@ ebt_check_entry(struct ebt_entry *e, str goto cleanup_watchers; } + /* Reject UNSPEC, xtables verdicts/return values are incompatible */ + if (target->family != NFPROTO_BRIDGE) { + module_put(target->me); + ret = -ENOENT; + goto cleanup_watchers; + } + t->u.target = target; if (t->u.target == &ebt_standard_target) { if (gap < sizeof(struct ebt_standard_target)) {