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authorPablo Neira Ayuso <pablo@netfilter.org>2015-08-28 21:01:43 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2015-08-29 01:02:35 +0200
commita9de9777d613500b089a7416f936bf3ae5f070d2 (patch)
treef27e19dd68a25992f8e5fed5acafee7d40a58d26 /net/netfilter
parent96be5f2806cd65a2ebced3bfcdf7df0116e6c4a6 (diff)
netfilter: nfnetlink: work around wrong endianess in res_id field
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 <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
-rw-r--r--net/netfilter/nfnetlink.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 0c0e8ecf02ab..70277b11f742 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);
}

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