[PATCH 3.16 178/245] netfilter: fix a use-after-free in mtype_destroy()
From: Ben Hutchings
Date: Thu Apr 23 2020 - 19:12:16 EST
3.16.83-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Cong Wang <xiyou.wangcong@xxxxxxxxx>
commit c120959387efa51479056fd01dc90adfba7a590c upstream.
map->members is freed by ip_set_free() right before using it in
mtype_ext_cleanup() again. So we just have to move it down.
Reported-by: syzbot+4c3cc6dbe7259dbf9054@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 40cd63bf33b2 ("netfilter: ipset: Support extensions which need a per data destroy function")
Acked-by: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
net/netfilter/ipset/ip_set_bitmap_gen.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/netfilter/ipset/ip_set_bitmap_gen.h
+++ b/net/netfilter/ipset/ip_set_bitmap_gen.h
@@ -66,12 +66,12 @@ mtype_destroy(struct ip_set *set)
if (SET_WITH_TIMEOUT(set))
del_timer_sync(&map->gc);
- ip_set_free(map->members);
if (set->dsize) {
if (set->extensions & IPSET_EXT_DESTROY)
mtype_ext_cleanup(set);
ip_set_free(map->extensions);
}
+ ip_set_free(map->members);
kfree(map);
set->data = NULL;