netfilter: ipset: Null pointer exception in ipset list:set
If we use before/after to add an element to an empty list it will cause
a kernel panic.
$> cat crash.restore
create a hash:ip
create b hash:ip
create test list:set timeout 5 size 4
add test b before a
$> ipset -R < crash.restore
Executing the above will crash the kernel.
Signed-off-by: Vishwanath Pai <vpai@akamai.com>
Reviewed-by: Josh Hunt <johunt@akamai.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c
index 51077c5..178d4eb 100644
--- a/net/netfilter/ipset/ip_set_list_set.c
+++ b/net/netfilter/ipset/ip_set_list_set.c
@@ -260,11 +260,14 @@ list_set_uadd(struct ip_set *set, void *value, const struct ip_set_ext *ext,
else
prev = e;
}
+
+ /* If before/after is used on an empty set */
+ if ((d->before > 0 && !next) ||
+ (d->before < 0 && !prev))
+ return -IPSET_ERR_REF_EXIST;
+
/* Re-add already existing element */
if (n) {
- if ((d->before > 0 && !next) ||
- (d->before < 0 && !prev))
- return -IPSET_ERR_REF_EXIST;
if (!flag_exist)
return -IPSET_ERR_EXIST;
/* Update extensions */