netfilter: ebt_ip6: allow matching on ipv6-icmp types/codes

To avoid adding a new match revision icmp type/code are stored
in the sport/dport area.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Holger Eitzenberger <holger@eitzenberger.org>
Reviewed-by: Bart De Schuymer<bdschuym@pandora.be>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/linux/netfilter_bridge/ebt_ip6.h b/include/linux/netfilter_bridge/ebt_ip6.h
index e5de987..22af18a 100644 (file)
--- a/include/linux/netfilter_bridge/ebt_ip6.h
+++ b/include/linux/netfilter_bridge/ebt_ip6.h
@@ -18,8 +18,11 @@
 #define EBT_IP6_PROTO 0x08
 #define EBT_IP6_SPORT 0x10
 #define EBT_IP6_DPORT 0x20
+#define EBT_IP6_ICMP6 0x40
+
 #define EBT_IP6_MASK (EBT_IP6_SOURCE | EBT_IP6_DEST | EBT_IP6_TCLASS |\
-                     EBT_IP6_PROTO | EBT_IP6_SPORT | EBT_IP6_DPORT)
+                     EBT_IP6_PROTO | EBT_IP6_SPORT | EBT_IP6_DPORT | \
+                     EBT_IP6_ICMP6)
 #define EBT_IP6_MATCH "ip6"
 
 /* the same values are used for the invflags */
@@ -32,8 +35,14 @@ struct ebt_ip6_info {
        uint8_t  protocol;
        uint8_t  bitmask;
        uint8_t  invflags;
-       uint16_t sport[2];
-       uint16_t dport[2];
+       union {
+               uint16_t sport[2];
+               uint8_t icmpv6_type[2];
+       };
+       union {
+               uint16_t dport[2];
+               uint8_t icmpv6_code[2];
+       };
 };
 
 #endif

diff --git a/net/bridge/netfilter/ebt_ip6.c b/net/bridge/netfilter/ebt_ip6.c
index 50a46af..2ed0056 100644 (file)
--- a/net/bridge/netfilter/ebt_ip6.c
+++ b/net/bridge/netfilter/ebt_ip6.c
@@ -22,9 +22,15 @@
 #include <linux/netfilter_bridge/ebtables.h>
 #include <linux/netfilter_bridge/ebt_ip6.h>
 
-struct tcpudphdr {
-       __be16 src;
-       __be16 dst;
+union pkthdr {
+       struct {
+               __be16 src;
+               __be16 dst;
+       } tcpudphdr;
+       struct {
+               u8 type;
+               u8 code;
+       } icmphdr;
 };
 
 static bool
@@ -33,8 +39,8 @@ ebt_ip6_mt(const struct sk_buff *skb, struct xt_action_param *par)
        const struct ebt_ip6_info *info = par->matchinfo;
        const struct ipv6hdr *ih6;
        struct ipv6hdr _ip6h;
-       const struct tcpudphdr *pptr;
-       struct tcpudphdr _ports;
+       const union pkthdr *pptr;
+       union pkthdr _pkthdr;
 
        ih6 = skb_header_pointer(skb, 0, sizeof(_ip6h), &_ip6h);
        if (ih6 == NULL)
@@ -56,26 +62,34 @@ ebt_ip6_mt(const struct sk_buff *skb, struct xt_action_param *par)
                        return false;
                if (FWINV(info->protocol != nexthdr, EBT_IP6_PROTO))
                        return false;
-               if (!(info->bitmask & EBT_IP6_DPORT) &&
-                   !(info->bitmask & EBT_IP6_SPORT))
+               if (!(info->bitmask & ( EBT_IP6_DPORT |
+                                       EBT_IP6_SPORT | EBT_IP6_ICMP6)))
                        return true;
-               pptr = skb_header_pointer(skb, offset_ph, sizeof(_ports),
-                                         &_ports);
+
+               /* min icmpv6 headersize is 4, so sizeof(_pkthdr) is ok. */
+               pptr = skb_header_pointer(skb, offset_ph, sizeof(_pkthdr),
+                                         &_pkthdr);
                if (pptr == NULL)
                        return false;
                if (info->bitmask & EBT_IP6_DPORT) {
-                       u32 dst = ntohs(pptr->dst);
+                       u16 dst = ntohs(pptr->tcpudphdr.dst);
                        if (FWINV(dst < info->dport[0] ||
                                  dst > info->dport[1], EBT_IP6_DPORT))
                                return false;
                }
                if (info->bitmask & EBT_IP6_SPORT) {
-                       u32 src = ntohs(pptr->src);
+                       u16 src = ntohs(pptr->tcpudphdr.src);
                        if (FWINV(src < info->sport[0] ||
                                  src > info->sport[1], EBT_IP6_SPORT))
                        return false;
                }
-               return true;
+               if ((info->bitmask & EBT_IP6_ICMP6) &&
+                    FWINV(pptr->icmphdr.type < info->icmpv6_type[0] ||
+                          pptr->icmphdr.type > info->icmpv6_type[1] ||
+                          pptr->icmphdr.code < info->icmpv6_code[0] ||
+                          pptr->icmphdr.code > info->icmpv6_code[1],
+                                                       EBT_IP6_ICMP6))
+                       return false;
        }
        return true;
 }
@@ -103,6 +117,14 @@ static int ebt_ip6_mt_check(const struct xt_mtchk_param *par)
                return -EINVAL;
        if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
                return -EINVAL;
+       if (info->bitmask & EBT_IP6_ICMP6) {
+               if ((info->invflags & EBT_IP6_PROTO) ||
+                    info->protocol != IPPROTO_ICMPV6)
+                       return -EINVAL;
+               if (info->icmpv6_type[0] > info->icmpv6_type[1] ||
+                   info->icmpv6_code[0] > info->icmpv6_code[1])
+                       return -EINVAL;
+       }
        return 0;
 }