ipv6: Do not leak throw route references

While commit 73ba57bfae4a ("ipv6: fix backtracking for throw routes")
does good job on error propagation to the fib_rules_lookup()
in fib rules core framework that also corrects throw routes
handling, it does not solve route reference leakage problem
happened when we return -EAGAIN to the fib_rules_lookup()
and leave routing table entry referenced in arg->result.

If rule with matched throw route isn't last matched in the
list we overwrite arg->result losing reference on throw
route stored previously forever.

We also partially revert commit ab997ad40839 ("ipv6: fix the
incorrect return value of throw route") since we never return
routing table entry with dst.error == -EAGAIN when
CONFIG_IPV6_MULTIPLE_TABLES is on. Also there is no point
to check for RTF_REJECT flag since it is always set throw
route.

Fixes: 73ba57bfae4a ("ipv6: fix backtracking for throw routes")
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 2 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index d4bf2c68a545..e6b78ba0e636 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -289,8 +289,7 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 	struct rt6_info *rt;
 
 	rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
-	if (rt->rt6i_flags & RTF_REJECT &&
-	    rt->dst.error == -EAGAIN) {
+	if (rt->dst.error == -EAGAIN) {
 		ip6_rt_put(rt);
 		rt = net->ipv6.ip6_null_entry;
 		dst_hold(&rt->dst);