From df18b50448fab1dff093731dfd0e25e77e1afcd1 Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Mon, 30 Jul 2018 16:23:10 +0200 Subject: [PATCH] net/ipv6: fix metrics leak Since commit d4ead6b34b67 ("net/ipv6: move metrics from dst to rt6_info"), ipv6 metrics are shared and refcounted. rt6_set_from() assigns the rt->from pointer and increases the refcount on from's metrics. This reference is never released. Introduce the fib6_metrics_release() helper and use it to release the metrics. Fixes: d4ead6b34b67 ("net/ipv6: move metrics from dst to rt6_info") Signed-off-by: Sabrina Dubroca Signed-off-by: David S. Miller --- net/ipv6/ip6_fib.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index d212738e9d10..211a2d437b56 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -167,11 +167,22 @@ struct fib6_info *fib6_info_alloc(gfp_t gfp_flags) return f6i; } +static void fib6_metrics_release(struct fib6_info *f6i) +{ + struct dst_metrics *m; + + if (!f6i) + return; + + m = f6i->fib6_metrics; + if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt)) + kfree(m); +} + void fib6_info_destroy_rcu(struct rcu_head *head) { struct fib6_info *f6i = container_of(head, struct fib6_info, rcu); struct rt6_exception_bucket *bucket; - struct dst_metrics *m; WARN_ON(f6i->fib6_node); @@ -201,9 +212,7 @@ void fib6_info_destroy_rcu(struct rcu_head *head) if (f6i->fib6_nh.nh_dev) dev_put(f6i->fib6_nh.nh_dev); - m = f6i->fib6_metrics; - if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt)) - kfree(m); + fib6_metrics_release(f6i); kfree(f6i); } @@ -887,6 +896,7 @@ static void fib6_drop_pcpu_from(struct fib6_info *f6i, from = rcu_dereference_protected(pcpu_rt->from, lockdep_is_held(&table->tb6_lock)); + fib6_metrics_release(from); rcu_assign_pointer(pcpu_rt->from, NULL); fib6_info_release(from); } -- GitLab