[PATCH 1/2] netfilter: ipset: Fix data race between add and list header in all hash types

[Jozsef Kadlecsik <kadlec@netfilter.org>]

The "ipset list -terse" command is actually a dump operation which
may run parallel with "ipset add" commands, which can trigger an
internal resizing of the hash type of sets just being dumped. However,
dumping just the header part of the set was not protected against
underlying resizing. Fix it by protecting the header dumping part
as well.

Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
---
 net/netfilter/ipset/ip_set_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index d0c9fe59c67d..e6a8b3acc556 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -1648,13 +1648,13 @@ ip_set_dump_do(struct sk_buff *skb, struct netlink_callback *cb)
 			if (cb->args[IPSET_CB_PROTO] > IPSET_PROTOCOL_MIN &&
 			    nla_put_net16(skb, IPSET_ATTR_INDEX, htons(index)))
 				goto nla_put_failure;
+			if (set->variant->uref)
+				set->variant->uref(set, cb, true);
 			ret = set->variant->head(set, skb);
 			if (ret < 0)
 				goto release_refcount;
 			if (dump_flags & IPSET_FLAG_LIST_HEADER)
 				goto next_set;
-			if (set->variant->uref)
-				set->variant->uref(set, cb, true);
 			fallthrough;
 		default:
 			ret = set->variant->list(set, skb, cb);
-- 
2.39.5