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ipv6: Do not leak throw route references 

While commit 73ba57bfae ("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 ab997ad408 ("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: 73ba57bfae ("ipv6: fix backtracking for throw routes")
Signed-off-by: Serhey Popovych <serhe.popovych@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Serhey Popovych 2017-06-20 13:29:25 +03:00 committed by David S. Miller
parent 7e113321ec
commit 07f615574f
2 changed files with 7 additions and 18 deletions
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22
net/ipv6/fib6_rules.c
View File

@ -32,7 +32,6 @@ struct fib6_rule {
struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
int flags, pol_lookup_t lookup) int flags, pol_lookup_t lookup)
{ {
struct rt6_info *rt;
struct fib_lookup_arg arg = { struct fib_lookup_arg arg = {
.lookup_ptr = lookup, .lookup_ptr = lookup,
.flags = FIB_LOOKUP_NOREF, .flags = FIB_LOOKUP_NOREF,
@ -44,21 +43,11 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
fib_rules_lookup(net->ipv6.fib6_rules_ops, fib_rules_lookup(net->ipv6.fib6_rules_ops,
flowi6_to_flowi(fl6), flags, &arg); flowi6_to_flowi(fl6), flags, &arg);
rt = arg.result; if (arg.result)
return arg.result;
if (!rt) { dst_hold(&net->ipv6.ip6_null_entry->dst);
dst_hold(&net->ipv6.ip6_null_entry->dst); return &net->ipv6.ip6_null_entry->dst;
return &net->ipv6.ip6_null_entry->dst;
}
if (rt->rt6i_flags & RTF_REJECT &&
rt->dst.error == -EAGAIN) {
ip6_rt_put(rt);
rt = net->ipv6.ip6_null_entry;
dst_hold(&rt->dst);
}
return &rt->dst;
} }
static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
@ -121,7 +110,8 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
flp6->saddr = saddr; flp6->saddr = saddr;
} }
err = rt->dst.error; err = rt->dst.error;
goto out; if (err != -EAGAIN)
goto out;
} }
again: again:
ip6_rt_put(rt); ip6_rt_put(rt);

3
net/ipv6/ip6_fib.c
View File

@ -289,8 +289,7 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
struct rt6_info *rt; struct rt6_info *rt;
rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags); rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
if (rt->rt6i_flags & RTF_REJECT && if (rt->dst.error == -EAGAIN) {
rt->dst.error == -EAGAIN) {
ip6_rt_put(rt); ip6_rt_put(rt);
rt = net->ipv6.ip6_null_entry; rt = net->ipv6.ip6_null_entry;
dst_hold(&rt->dst); dst_hold(&rt->dst);