netfilter: ipt_ecn: fix inversion for IP header ECN match
Userspace allows to specify inversion for IP header ECN matches, the
kernel silently accepts it, but doesn't invert the match result.
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/ipv4/netfilter/ipt_ecn.c b/net/ipv4/netfilter/ipt_ecn.c
index aaa85be..2b57e52 100644
--- a/net/ipv4/netfilter/ipt_ecn.c
+++ b/net/ipv4/netfilter/ipt_ecn.c
@@ -25,7 +25,8 @@
static inline bool match_ip(const struct sk_buff *skb,
const struct ipt_ecn_info *einfo)
{
- return (ip_hdr(skb)->tos & IPT_ECN_IP_MASK) == einfo->ip_ect;
+ return ((ip_hdr(skb)->tos & IPT_ECN_IP_MASK) == einfo->ip_ect) ^
+ !!(einfo->invert & IPT_ECN_OP_MATCH_IP);
}
static inline bool match_tcp(const struct sk_buff *skb,