Fix parallel resizing and listing of the same set

When elements added to a hash:* type of set and resizing triggered,
parallel listing could start to list the original set (before resizing)
and "continue" with listing the new set. Fix it by references and
using the original hash table for listing. Therefore the destroying
the original hash table may happen from the resizing or listing functions.

1 files changed, 17 insertions, 13 deletions

diff --git a/kernel/net/netfilter/ipset/ip_set_core.c b/kernel/net/netfilter/ipset/ip_set_core.c
index b0b9611..872f71e 100644
--- a/kernel/net/netfilter/ipset/ip_set_core.c
+++ b/kernel/net/netfilter/ipset/ip_set_core.c
@@ -1185,13 +1185,16 @@ ip_set_swap(struct sock *ctnl, struct sk_buff *skb,
 static int
 ip_set_dump_done(struct netlink_callback *cb)
 {
-	struct ip_set_net *inst = (struct ip_set_net *)cb->args[IPSET_CB_NET];
-
 	if (cb->args[IPSET_CB_ARG0]) {
-		pr_debug("release set %s\n",
-			 ip_set(inst, cb->args[IPSET_CB_INDEX])->name);
-		__ip_set_put_byindex(inst,
-			(ip_set_id_t) cb->args[IPSET_CB_INDEX]);
+		struct ip_set_net *inst =
+			(struct ip_set_net *)cb->args[IPSET_CB_NET];
+		ip_set_id_t index = (ip_set_id_t) cb->args[IPSET_CB_INDEX];
+		struct ip_set *set = ip_set(inst, index);
+
+		if (set->variant->uref)
+			set->variant->uref(set, cb, false);
+		pr_debug("release set %s\n", set->name);
+		__ip_set_put_byindex(inst, index);
 	}
 	return 0;
 }
@@ -1222,12 +1225,6 @@ dump_init(struct netlink_callback *cb, struct ip_set_net *inst)
 	nla_parse(cda, IPSET_ATTR_CMD_MAX,
 		  attr, nlh->nlmsg_len - min_len, ip_set_setname_policy);
 
-	/* cb->args[IPSET_CB_NET]:	net namespace
-	 *         [IPSET_CB_DUMP]:	dump single set/all sets
-	 *         [IPSET_CB_INDEX]:	set index
-	 *         [IPSET_CB_ARG0]:	type specific
-	 */
-
 	if (cda[IPSET_ATTR_SETNAME]) {
 		struct ip_set *set;
 
@@ -1335,6 +1332,8 @@ dump_last:
 				goto release_refcount;
 			if (dump_flags & IPSET_FLAG_LIST_HEADER)
 				goto next_set;
+			if (set->variant->uref)
+				set->variant->uref(set, cb, true);
 			/* Fall through and add elements */
 		default:
 			rcu_read_lock_bh();
@@ -1351,6 +1350,8 @@ dump_last:
 		dump_type = DUMP_LAST;
 		cb->args[IPSET_CB_DUMP] = dump_type | (dump_flags << 16);
 		cb->args[IPSET_CB_INDEX] = 0;
+		if (set && set->variant->uref)
+			set->variant->uref(set, cb, false);
 		goto dump_last;
 	}
 	goto out;
@@ -1365,7 +1366,10 @@ next_set:
 release_refcount:
 	/* If there was an error or set is done, release set */
 	if (ret || !cb->args[IPSET_CB_ARG0]) {
-		pr_debug("release set %s\n", ip_set(inst, index)->name);
+		set = ip_set(inst, index);
+		if (set->variant->uref)
+			set->variant->uref(set, cb, false);
+		pr_debug("release set %s\n", set->name);
 		__ip_set_put_byindex(inst, index);
 		cb->args[IPSET_CB_ARG0] = 0;
 	}