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ipv6: drop packets with multiple fragmentation headers 

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>
This commit is contained in:
Hannes Frederic Sowa 2013-08-16 13:30:07 +02:00 committed by David S. Miller
parent 4b08a8f1bd
commit f46078cfcd
2 changed files with 6 additions and 0 deletions
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1
include/linux/ipv6.h
View File

@ -101,6 +101,7 @@ struct inet6_skb_parm {
#define IP6SKB_FORWARDED 2
#define IP6SKB_REROUTED 4
#define IP6SKB_ROUTERALERT 8
#define IP6SKB_FRAGMENTED 16
};
#define IP6CB(skb) ((struct inet6_skb_parm*)((skb)->cb))

5
net/ipv6/reassembly.c
View File

@ -490,6 +490,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff *prev,
ipv6_hdr(head)->payload_len = htons(payload_len);
ipv6_change_dsfield(ipv6_hdr(head), 0xff, ecn);
IP6CB(head)->nhoff = nhoff;
IP6CB(head)->flags |= IP6SKB_FRAGMENTED;
/* Yes, and fold redundant checksum back. 8) */
if (head->ip_summed == CHECKSUM_COMPLETE)
@ -524,6 +525,9 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
struct net *net = dev_net(skb_dst(skb)->dev);
int evicted;
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 */
@ -544,6 +548,7 @@ 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;
}