netfilter: nf_nat: remove obsolete check in nf_nat_mangle_udp_packet()

The packet size check originates from a time when UDP helpers could
accidentally mangle incorrect packets (NEWNAT) and is unnecessary
nowadays since the conntrack helpers invoke the NAT helpers for the
proper packet directly.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 0 insertions, 6 deletions

diff --git a/net/ipv4/netfilter/nf_nat_helper.c b/net/ipv4/netfilter/nf_nat_helper.c
index 049e8b7c3188..af65958f6308 100644
--- a/net/ipv4/netfilter/nf_nat_helper.c
+++ b/net/ipv4/netfilter/nf_nat_helper.c
@@ -253,12 +253,6 @@ nf_nat_mangle_udp_packet(struct sk_buff *skb,
         struct udphdr *udph;
         int datalen, oldlen;
 
-        /* UDP helpers might accidentally mangle the wrong packet */
-        iph = ip_hdr(skb);
-        if (skb->len < iph->ihl*4 + sizeof(*udph) +
-                               match_offset + match_len)
-                return 0;
-
         if (!skb_make_writable(skb, skb->len))
                 return 0;