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>

1 files changed, 19 insertions, 7 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 57e01bc60947..ca5e237df029 100644
--- 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();