ipv4: Perform peer validation on cached route lookup.

Otherwise we won't notice the peer GENID change.

Reported-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 57e01bc..ca5e237 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1693,12 +1693,8 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
 }
 
 
-static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
+static struct rtable *ipv4_validate_peer(struct rtable *rt)
 {
-       struct rtable *rt = (struct rtable *) dst;
-
-       if (rt_is_expired(rt))
-               return NULL;
        if (rt->rt_peer_genid != rt_peer_genid()) {
                struct inet_peer *peer;
 
@@ -1707,19 +1703,29 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
 
                peer = rt->peer;
                if (peer) {
-                       check_peer_pmtu(dst, peer);
+                       check_peer_pmtu(&rt->dst, peer);
 
                        if (peer->redirect_genid != redirect_genid)
                                peer->redirect_learned.a4 = 0;
                        if (peer->redirect_learned.a4 &&
                            peer->redirect_learned.a4 != rt->rt_gateway) {
-                               if (check_peer_redir(dst, peer))
+                               if (check_peer_redir(&rt->dst, peer))
                                        return NULL;
                        }
                }
 
                rt->rt_peer_genid = rt_peer_genid();
        }
+       return rt;
+}
+
+static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
+{
+       struct rtable *rt = (struct rtable *) dst;
+
+       if (rt_is_expired(rt))
+               return NULL;
+       dst = (struct dst_entry *) ipv4_validate_peer(rt);
        return dst;
 }
 
@@ -2374,6 +2380,9 @@ int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
                    rth->rt_mark == skb->mark &&
                    net_eq(dev_net(rth->dst.dev), net) &&
                    !rt_is_expired(rth)) {
+                       rth = ipv4_validate_peer(rth);
+                       if (!rth)
+                               continue;
                        if (noref) {
                                dst_use_noref(&rth->dst, jiffies);
                                skb_dst_set_noref(skb, &rth->dst);
@@ -2749,6 +2758,9 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4)
                            (IPTOS_RT_MASK | RTO_ONLINK)) &&
                    net_eq(dev_net(rth->dst.dev), net) &&
                    !rt_is_expired(rth)) {
+                       rth = ipv4_validate_peer(rth);
+                       if (!rth)
+                               continue;
                        dst_use(&rth->dst, jiffies);
                        RT_CACHE_STAT_INC(out_hit);
                        rcu_read_unlock_bh();