From: Pavel Tikhomirov ptikhomirov@virtuozzo.com
[ Upstream commit 0af8c09c896810879387decfba8c942994bb61f5 ]
Here is the stack where we allocate percpu counter block:
+-< __alloc_percpu +-< xt_percpu_counter_alloc +-< find_check_entry # {arp,ip,ip6}_tables.c +-< translate_table
And it can be leaked on this code path:
+-> ip6t_register_table +-> translate_table # allocates percpu counter block +-> xt_register_table # fails
there is no freeing of the counter block on xt_register_table fail. Note: xt_percpu_counter_free should be called to free it like we do in do_replace through cleanup_entry helper (or in __ip6t_unregister_table).
Probability of hitting this error path is low AFAICS (xt_register_table can only return ENOMEM here, as it is not replacing anything, as we are creating new netns, and it is hard to imagine that all previous allocations succeeded and after that one in xt_register_table failed). But it's worth fixing even the rare leak.
Fixes: 71ae0dff02d7 ("netfilter: xtables: use percpu rule counters") Signed-off-by: Pavel Tikhomirov ptikhomirov@virtuozzo.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/netfilter/arp_tables.c | 4 ++++ net/ipv4/netfilter/ip_tables.c | 4 ++++ net/ipv6/netfilter/ip6_tables.c | 4 ++++ 3 files changed, 12 insertions(+)
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index c53f14b943560..71bf3aeed73c1 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -1524,6 +1524,10 @@ int arpt_register_table(struct net *net,
new_table = xt_register_table(net, table, &bootstrap, newinfo); if (IS_ERR(new_table)) { + struct arpt_entry *iter; + + xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) + cleanup_entry(iter, net); xt_free_table_info(newinfo); return PTR_ERR(new_table); } diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 91301dc3924a2..a748a1e754605 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1740,6 +1740,10 @@ int ipt_register_table(struct net *net, const struct xt_table *table,
new_table = xt_register_table(net, table, &bootstrap, newinfo); if (IS_ERR(new_table)) { + struct ipt_entry *iter; + + xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) + cleanup_entry(iter, net); xt_free_table_info(newinfo); return PTR_ERR(new_table); } diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 7ba68388d2e1f..277a5ee887eb3 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -1750,6 +1750,10 @@ int ip6t_register_table(struct net *net, const struct xt_table *table,
new_table = xt_register_table(net, table, &bootstrap, newinfo); if (IS_ERR(new_table)) { + struct ip6t_entry *iter; + + xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) + cleanup_entry(iter, net); xt_free_table_info(newinfo); return PTR_ERR(new_table); }