ipv6: drop packets with multiple fragmentation headers
[ Upstream commit f46078cfcd77fa5165bf849f5e568a7ac5fa569c ]
It is not allowed for an ipv6 packet to contain multiple fragmentation
headers. So discard packets which were already reassembled by
fragmentation logic and send back a parameter problem icmp.
The updates for RFC 6980 will come in later, I have to do a bit more
research here.
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index e5bf08e..383a9d4 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -266,6 +266,7 @@
#define IP6SKB_XFRM_TRANSFORMED 1
#define IP6SKB_FORWARDED 2
#define IP6SKB_REROUTED 4
+#define IP6SKB_FRAGMENTED 16
};
#define IP6CB(skb) ((struct inet6_skb_parm*)((skb)->cb))
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 6bda7aa..ff900ac 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -516,6 +516,7 @@
head->tstamp = fq->q.stamp;
ipv6_hdr(head)->payload_len = htons(payload_len);
IP6CB(head)->nhoff = nhoff;
+ IP6CB(head)->flags |= IP6SKB_FRAGMENTED;
/* Yes, and fold redundant checksum back. 8) */
if (head->ip_summed == CHECKSUM_COMPLETE)
@@ -551,6 +552,9 @@
const struct ipv6hdr *hdr = ipv6_hdr(skb);
struct net *net = dev_net(skb_dst(skb)->dev);
+ if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED)
+ goto fail_hdr;
+
IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMREQDS);
/* Jumbo payload inhibits frag. header */
@@ -571,6 +575,7 @@
ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_REASMOKS);
IP6CB(skb)->nhoff = (u8 *)fhdr - skb_network_header(skb);
+ IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
return 1;
}