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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81E1BCCA479 for ; Mon, 20 Jun 2022 14:57:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239080AbiFTO5h (ORCPT ); Mon, 20 Jun 2022 10:57:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242963AbiFTO5K (ORCPT ); Mon, 20 Jun 2022 10:57:10 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1878B1D32F for ; Mon, 20 Jun 2022 07:17:46 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1o3IDo-00052h-Kh; Mon, 20 Jun 2022 16:17:44 +0200 From: Florian Westphal To: Cc: Florian Westphal Subject: [PATCH nf 2/2] netfilter: nf_dup_netdev: add and use recursion counter Date: Mon, 20 Jun 2022 16:17:31 +0200 Message-Id: <20220620141731.7362-3-fw@strlen.de> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220620141731.7362-1-fw@strlen.de> References: <20220620141731.7362-1-fw@strlen.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Now that the egress function can be called from egress hook, we need to avoid recursive calls into the nf_tables traverser, else crash. Fixes: f87b9464d152 ("netfilter: nft_fwd_netdev: Support egress hook") Signed-off-by: Florian Westphal --- net/netfilter/nf_dup_netdev.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_dup_netdev.c b/net/netfilter/nf_dup_netdev.c index 13b7f6a66086..a8e2425e43b0 100644 --- a/net/netfilter/nf_dup_netdev.c +++ b/net/netfilter/nf_dup_netdev.c @@ -13,20 +13,31 @@ #include #include +#define NF_RECURSION_LIMIT 2 + +static DEFINE_PER_CPU(u8, nf_dup_skb_recursion); + static void nf_do_netdev_egress(struct sk_buff *skb, struct net_device *dev, enum nf_dev_hooks hook) { + if (__this_cpu_read(nf_dup_skb_recursion) > NF_RECURSION_LIMIT) + goto err; + if (hook == NF_NETDEV_INGRESS && skb_mac_header_was_set(skb)) { - if (skb_cow_head(skb, skb->mac_len)) { - kfree_skb(skb); - return; - } + if (skb_cow_head(skb, skb->mac_len)) + goto err; + skb_push(skb, skb->mac_len); } skb->dev = dev; skb_clear_tstamp(skb); + __this_cpu_inc(nf_dup_skb_recursion); dev_queue_xmit(skb); + __this_cpu_dec(nf_dup_skb_recursion); + return; +err: + kfree_skb(skb); } void nf_fwd_netdev_egress(const struct nft_pktinfo *pkt, int oif) -- 2.35.1