From 16e6df022b41901165f67c30f807074fd6c4507b Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 28 Aug 2015 21:01:43 +0200 Subject: [PATCH] netfilter: nfnetlink: work around wrong endianess in res_id field commit a9de9777d613500b089a7416f936bf3ae5f070d2 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- 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 8b117c90ecd765..69e3ceffa14dd3 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -432,6 +432,7 @@ static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh, 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 || @@ -456,7 +457,12 @@ 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); }