netfilter: nfnetlink: validate nfnetlink header from batch

Make sure there is enough room for the nfnetlink header in the
netlink messages that are part of the batch. There is a similar
check in netlink_rcv_skb().

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 13c2e17..c6619d4 100644 (file)
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -321,7 +321,8 @@ replay:
                nlh = nlmsg_hdr(skb);
                err = 0;
 
-               if (nlh->nlmsg_len < NLMSG_HDRLEN) {
+               if (nlmsg_len(nlh) < sizeof(struct nfgenmsg) ||
+                   skb->len < nlh->nlmsg_len) {
                        err = -EINVAL;
                        goto ack;
                }