[PATCH 4.4 10/66] ipv6: fix memory leak with multiple tables during netns destruction

Greg Kroah-Hartman
2017-09-24T20:34:13Z

From: Sabrina Dubroca <sd@queasysnail.net>

[ Upstream commit ba1cc08d9488c94cb8d94f545305688b72a2a300 ]

fib6_net_exit only frees the main and local tables. If another table was
created with fib6_alloc_table, we leak it when the netns is destroyed.

Fix this in the same way ip_fib_net_exit cleans up tables, by walking
through the whole hashtable of fib6_table's. We can get rid of the
special cases for local and main, since they're also part of the
hashtable.

Reproducer:
ip netns add x
ip -net x -6 rule add from 6003:1::/64 table 100
ip netns del x

Reported-by: Jianlin Shi <jishi@redhat.com>
Fixes: 58f09b78b730 ("[NETNS][IPV6] ip6_fib - make it per network namespace")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/ip6_fib.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)

--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -203,6 +203,12 @@ static void rt6_release(struct rt6_info
}
}

+static void fib6_free_table(struct fib6_table *table)
+{
+ inetpeer_invalidate_tree(&table->tb6_peers);
+ kfree(table);
+}
+
static void fib6_link_table(struct net *net, struct fib6_table *tb)
{
unsigned int h;
@@ -1885,15 +1891,22 @@ out_timer:

static void fib6_net_exit(struct net *net)
{
+ unsigned int i;
+
rt6_ifdown(net, NULL);
del_timer_sync(&net->ipv6.ip6_fib_timer);

-#ifdef CONFIG_IPV6_MULTIPLE_TABLES
- inetpeer_invalidate_tree(&net->ipv6.fib6_local_tbl->tb6_peers);
- kfree(net->ipv6.fib6_local_tbl);
-#endif
- inetpeer_invalidate_tree(&net->ipv6.fib6_main_tbl->tb6_peers);
- kfree(net->ipv6.fib6_main_tbl);
+ for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
+ struct hlist_head *head = &net->ipv6.fib_table_hash[i];
+ struct hlist_node *tmp;
+ struct fib6_table *tb;
+
+ hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
+ hlist_del(&tb->tb6_hlist);
+ fib6_free_table(tb);
+ }
+ }
+
kfree(net->ipv6.fib_table_hash);
kfree(net->ipv6.rt6_stats);
}