ipv6: Do not leak throw route references
flat view
From: Serhey Popovych <hidden>
Date: 2017-06-16 11:42:39
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
While commit 73ba57b (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 loosing reference on throw route stored previously forever. We also partially revert commit ab997ad (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: 73ba57b (ipv6: fix backtracking for throw routes) Signed-off-by: Serhey Popovych <redacted> --- net/ipv6/fib6_rules.c | 22 ++++++---------------- net/ipv6/ip6_fib.c | 3 +-- 2 files changed, 7 insertions(+), 18 deletions(-)
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 11318b7..65a3c62 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c@@ -33,7 +33,6 @@ struct fib6_rule struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, int flags, pol_lookup_t lookup) { - struct rt6_info *rt; struct fib_lookup_arg arg = { .lookup_ptr = lookup, .flags = FIB_LOOKUP_NOREF,
@@ -42,21 +41,11 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, fib_rules_lookup(net->ipv6.fib6_rules_ops, 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); - 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; + dst_hold(&net->ipv6.ip6_null_entry->dst); + return &net->ipv6.ip6_null_entry->dst; } static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
@@ -117,7 +106,8 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, ipv6_addr_copy(&flp6->saddr, &saddr); } err = rt->dst.error; - goto out; + if (err != -EAGAIN) + goto out; } again: ip6_rt_put(rt);
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index d3cd013..32f91cd 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c@@ -249,8 +249,7 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, table = fib6_get_table(net, RT6_TABLE_MAIN); if (table) { rt = lookup(net, table, fl6, flags); - if (rt->rt6i_flags & RTF_REJECT && - rt->dst.error == -EAGAIN) { + if (rt->dst.error == -EAGAIN) { ip6_rt_put(rt); rt = NULL; }
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1.7.10.4