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: Willy Tarreau <w@1wt.eu>

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index c662efa6828985a4025951a1c655cf5bf85300cf..5bf3324ff5a39ecfb2ac323188772560ebe0fd09 100644 (file)
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -248,6 +248,7 @@ struct inet6_skb_parm {
 
 #define IP6SKB_XFRM_TRANSFORMED        1
 #define IP6SKB_FORWARDED       2
+#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 105de22cc0381f53a9e8ed2f39c84bd35281c9db..0c09d8e80c05a2fc1f76c96e16d1e99eacaa53e2 100644 (file)
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -503,6 +503,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
        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)
@@ -537,6 +538,9 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
        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 */
@@ -557,6 +561,7 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
                                 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;
        }