From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 30/50] netfilter: ingress: translate 0 nf_hook_slow retval to -1 Date: Wed, 7 Dec 2016 22:52:36 +0100 Message-ID: <1481147576-5690-31-git-send-email-pablo@netfilter.org> References: <1481147576-5690-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: Received: from mail.us.es ([193.147.175.20]:60188 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933376AbcLGVxq (ORCPT ); Wed, 7 Dec 2016 16:53:46 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 34C0296ED2 for ; Wed, 7 Dec 2016 22:53:44 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 16310DA849 for ; Wed, 7 Dec 2016 22:53:44 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 07884DA848 for ; Wed, 7 Dec 2016 22:53:42 +0100 (CET) In-Reply-To: <1481147576-5690-1-git-send-email-pablo@netfilter.org> Sender: netdev-owner@vger.kernel.org List-ID: From: Florian Westphal The caller assumes that < 0 means that skb was stolen (or free'd). All other return values continue skb processing. nf_hook_slow returns 3 different return value types: A) a (negative) errno value: the skb was dropped (NF_DROP, e.g. by iptables '-j DROP' rule). B) 0. The skb was stolen by the hook or queued to userspace. C) 1. all hooks returned NF_ACCEPT so the caller should invoke the okfn so packet processing can continue. nft ingress facility currently doesn't have the 'okfn' that the NF_HOOK() macros use; there is no nfqueue support either. So 1 means that nf_hook_ingress() caller should go on processing the skb. In order to allow use of NF_STOLEN from ingress we need to translate this to an errno number, else we'd crash because we continue with already-free'd (or about to be free-d) skb. The errno value isn't checked, its just important that its less than 0, so return -1. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter_ingress.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/netfilter_ingress.h b/include/linux/netfilter_ingress.h index 2dc3b49b804a..59476061de86 100644 --- a/include/linux/netfilter_ingress.h +++ b/include/linux/netfilter_ingress.h @@ -19,6 +19,7 @@ static inline int nf_hook_ingress(struct sk_buff *skb) { struct nf_hook_entry *e = rcu_dereference(skb->dev->nf_hooks_ingress); struct nf_hook_state state; + int ret; /* Must recheck the ingress hook head, in the event it became NULL * after the check in nf_hook_ingress_active evaluated to true. @@ -29,7 +30,11 @@ static inline int nf_hook_ingress(struct sk_buff *skb) nf_hook_state_init(&state, NF_NETDEV_INGRESS, NFPROTO_NETDEV, skb->dev, NULL, NULL, dev_net(skb->dev), NULL); - return nf_hook_slow(skb, &state, e); + ret = nf_hook_slow(skb, &state, e); + if (ret == 0) + return -1; + + return ret; } static inline void nf_hook_ingress_init(struct net_device *dev) -- 2.1.4