ipv4: Fix peer validation on cached lookup.
If ipv4_valdiate_peer() fails during a cached entry lookup, we'll NULL derer since the loop iterator assumes rth is not NULL. Letting this be handled as a failure is just bogus, so just make it not fail. If we have trouble getting a non-NULL neighbour for the redirected gateway, just restore the original gateway and continue. The very next use of this cached route will try again. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -1310,7 +1310,7 @@ static void rt_del(unsigned hash, struct rtable *rt)
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spin_unlock_bh(rt_hash_lock_addr(hash));
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}
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static int check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
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static void check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
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{
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struct rtable *rt = (struct rtable *) dst;
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__be32 orig_gw = rt->rt_gateway;
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@ -1321,21 +1321,19 @@ static int check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
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rt->rt_gateway = peer->redirect_learned.a4;
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n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
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if (IS_ERR(n))
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return PTR_ERR(n);
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if (IS_ERR(n)) {
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rt->rt_gateway = orig_gw;
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return;
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}
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old_n = xchg(&rt->dst._neighbour, n);
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if (old_n)
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neigh_release(old_n);
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if (!n || !(n->nud_state & NUD_VALID)) {
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if (n)
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neigh_event_send(n, NULL);
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rt->rt_gateway = orig_gw;
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return -EAGAIN;
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if (!(n->nud_state & NUD_VALID)) {
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neigh_event_send(n, NULL);
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} else {
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rt->rt_flags |= RTCF_REDIRECTED;
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call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
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}
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return 0;
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}
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/* called in rcu_read_lock() section */
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@ -1693,7 +1691,7 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
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}
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static struct rtable *ipv4_validate_peer(struct rtable *rt)
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static void ipv4_validate_peer(struct rtable *rt)
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{
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if (rt->rt_peer_genid != rt_peer_genid()) {
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struct inet_peer *peer;
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@ -1708,15 +1706,12 @@ static struct rtable *ipv4_validate_peer(struct rtable *rt)
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if (peer->redirect_genid != redirect_genid)
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peer->redirect_learned.a4 = 0;
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if (peer->redirect_learned.a4 &&
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peer->redirect_learned.a4 != rt->rt_gateway) {
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if (check_peer_redir(&rt->dst, peer))
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return NULL;
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}
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peer->redirect_learned.a4 != rt->rt_gateway)
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check_peer_redir(&rt->dst, peer);
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}
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rt->rt_peer_genid = rt_peer_genid();
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}
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return rt;
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}
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static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
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@ -1725,7 +1720,7 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
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if (rt_is_expired(rt))
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return NULL;
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dst = (struct dst_entry *) ipv4_validate_peer(rt);
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ipv4_validate_peer(rt);
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return dst;
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}
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@ -2380,9 +2375,7 @@ int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
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rth->rt_mark == skb->mark &&
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net_eq(dev_net(rth->dst.dev), net) &&
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!rt_is_expired(rth)) {
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rth = ipv4_validate_peer(rth);
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if (!rth)
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continue;
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ipv4_validate_peer(rth);
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if (noref) {
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dst_use_noref(&rth->dst, jiffies);
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skb_dst_set_noref(skb, &rth->dst);
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@ -2758,9 +2751,7 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *flp4)
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(IPTOS_RT_MASK | RTO_ONLINK)) &&
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net_eq(dev_net(rth->dst.dev), net) &&
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!rt_is_expired(rth)) {
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rth = ipv4_validate_peer(rth);
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if (!rth)
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continue;
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ipv4_validate_peer(rth);
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dst_use(&rth->dst, jiffies);
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RT_CACHE_STAT_INC(out_hit);
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rcu_read_unlock_bh();
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