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route: fix ICMP redirect validation 

The commit f39925dbde
(ipv4: Cache learned redirect information in inetpeer.)
removed some ICMP packet validations which are required by
RFC 1122, section 3.2.2.2:
...
  A Redirect message SHOULD be silently discarded if the new
  gateway address it specifies is not on the same connected
  (sub-) net through which the Redirect arrived [INTRO:2,
  Appendix A], or if the source of the Redirect is not the
  current first-hop gateway for the specified destination (see
  Section 3.3.1).

Signed-off-by: Flavio Leitner <fbl@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Flavio Leitner 2011-10-24 02:56:38 -04:00 committed by David S. Miller
parent da92b194cc
commit 7cc9150ebe
1 changed files with 31 additions and 5 deletions
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36
net/ipv4/route.c
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@ -1309,7 +1309,12 @@ static void rt_del(unsigned hash, struct rtable *rt)
void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
__be32 saddr, struct net_device *dev)
{
int s, i;
struct in_device *in_dev = __in_dev_get_rcu(dev);
struct rtable *rt;
__be32 skeys[2] = { saddr, 0 };
int ikeys[2] = { dev->ifindex, 0 };
struct flowi4 fl4;
struct inet_peer *peer;
struct net *net;
@ -1332,13 +1337,34 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
goto reject_redirect;
}
peer = inet_getpeer_v4(daddr, 1);
if (peer) {
peer->redirect_learned.a4 = new_gw;
memset(&fl4, 0, sizeof(fl4));
fl4.daddr = daddr;
for (s = 0; s < 2; s++) {
for (i = 0; i < 2; i++) {
fl4.flowi4_oif = ikeys[i];
fl4.saddr = skeys[s];
rt = __ip_route_output_key(net, &fl4);
if (IS_ERR(rt))
continue;
inet_putpeer(peer);
if (rt->dst.error || rt->dst.dev != dev ||
rt->rt_gateway != old_gw) {
ip_rt_put(rt);
continue;
}
atomic_inc(&__rt_peer_genid);
if (!rt->peer)
rt_bind_peer(rt, rt->rt_dst, 1);
peer = rt->peer;
if (peer) {
peer->redirect_learned.a4 = new_gw;
atomic_inc(&__rt_peer_genid);
}
ip_rt_put(rt);
return;
}
}
return;