netfilter: ip6t_ipv6header: fix match on packets ending with NEXTHDR_NONE

As packets ending with NEXTHDR_NONE don't have a last extension header,
the check for the length needs to be after the check for NEXTHDR_NONE.

Signed-off-by: Christoph Paasch <christoph.paasch@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv6/netfilter/ip6t_ipv6header.c b/net/ipv6/netfilter/ip6t_ipv6header.c
index 14e6724d5672..91490ad9302c 100644
--- a/net/ipv6/netfilter/ip6t_ipv6header.c
+++ b/net/ipv6/netfilter/ip6t_ipv6header.c
@@ -50,14 +50,14 @@ ipv6header_mt6(const struct sk_buff *skb, const struct xt_match_param *par)
                 struct ipv6_opt_hdr _hdr;
                 int hdrlen;
 
-                /* Is there enough space for the next ext header? */
-                if (len < (int)sizeof(struct ipv6_opt_hdr))
-                        return false;
                 /* No more exthdr -> evaluate */
                 if (nexthdr == NEXTHDR_NONE) {
                         temp |= MASK_NONE;
                         break;
                 }
+                /* Is there enough space for the next ext header? */
+                if (len < (int)sizeof(struct ipv6_opt_hdr))
+                        return false;
                 /* ESP -> evaluate */
                 if (nexthdr == NEXTHDR_ESP) {
                         temp |= MASK_ESP;