From 40b446a1d8af17274746ff7079aa0a618dffbac3 Mon Sep 17 00:00:00 2001 From: Vishwanath Pai Date: Thu, 16 Feb 2017 20:55:45 +0100 Subject: [PATCH] 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 Reviewed-by: Josh Hunt Signed-off-by: Jozsef Kadlecsik --- net/netfilter/ipset/ip_set_list_set.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c index 51077c53d76b..178d4eba013b 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 */ -- 2.39.5