ip: generate unique IP identificator if local fragmentation is allowed

If local fragmentation is allowed, then ip_select_ident() and
ip_select_ident_more() need to generate unique IDs to ensure
correct defragmentation on the peer.

For example, if IPsec (tunnel mode) has to encrypt large skbs
that have local_df bit set, then all IP fragments that belonged
to different ESP datagrams would have used the same identificator.
If one of these IP fragments would get lost or reordered, then
peer could possibly stitch together wrong IP fragments that did
not belong to the same datagram. This would lead to a packet loss
or data corruption.

Signed-off-by: Ansis Atteka <aatteka@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index d6c0e64ec97f..dace87f06e5f 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -369,7 +369,7 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
         pip->saddr    = fl4.saddr;
         pip->protocol = IPPROTO_IGMP;
         pip->tot_len  = 0;      /* filled in later */
-        ip_select_ident(pip, &rt->dst, NULL);
+        ip_select_ident(skb, &rt->dst, NULL);
         ((u8 *)&pip[1])[0] = IPOPT_RA;
         ((u8 *)&pip[1])[1] = 4;
         ((u8 *)&pip[1])[2] = 0;
@@ -714,7 +714,7 @@ static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
         iph->daddr    = dst;
         iph->saddr    = fl4.saddr;
         iph->protocol = IPPROTO_IGMP;
-        ip_select_ident(iph, &rt->dst, NULL);
+        ip_select_ident(skb, &rt->dst, NULL);
         ((u8 *)&iph[1])[0] = IPOPT_RA;
         ((u8 *)&iph[1])[1] = 4;
         ((u8 *)&iph[1])[2] = 0;