From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 5/6] netfilter: nfnetlink: work around wrong endianess in res_id field Date: Thu, 3 Sep 2015 11:51:00 +0200 Message-ID: <1441273861-31092-6-git-send-email-pablo@netfilter.org> References: <1441273861-31092-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: In-Reply-To: <1441273861-31092-1-git-send-email-pablo@netfilter.org> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org The convention in nfnetlink is to use network byte order in every header field as well as in the attribute payload. The initial version of the batching infrastructure assumes that res_id comes in host byte order though. The only client of the batching infrastructure is nf_tables, so let's add a workaround to address this inconsistency. We currently have 11 nfnetlink subsystems according to NFNL_SUBSYS_COUNT, so we can assume that the subsystem 2560, ie. htons(10), will not be allocated anytime soon, so it can be an alias of nf_tables from the nfnetlink batching path when interpreting the res_id field. Based on original patch from Florian Westphal. Reported-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index 0c0e8ec..70277b1 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -444,6 +444,7 @@ done: static void nfnetlink_rcv(struct sk_buff *skb) { struct nlmsghdr *nlh = nlmsg_hdr(skb); + u_int16_t res_id; int msglen; if (nlh->nlmsg_len < NLMSG_HDRLEN || @@ -468,7 +469,12 @@ static void nfnetlink_rcv(struct sk_buff *skb) nfgenmsg = nlmsg_data(nlh); skb_pull(skb, msglen); - nfnetlink_rcv_batch(skb, nlh, nfgenmsg->res_id); + /* Work around old nft using host byte order */ + if (nfgenmsg->res_id == NFNL_SUBSYS_NFTABLES) + res_id = NFNL_SUBSYS_NFTABLES; + else + res_id = ntohs(nfgenmsg->res_id); + nfnetlink_rcv_batch(skb, nlh, res_id); } else { netlink_rcv_skb(skb, &nfnetlink_rcv_msg); } -- 1.7.10.4