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[5/8] netfilter: ipset: Null pointer exception in ipset list:set

Message ID 1487848449-2731-6-git-send-email-pablo@netfilter.org
State Accepted
Delegated to: Pablo Neira
Headers show

Commit Message

Pablo Neira Ayuso Feb. 23, 2017, 11:14 a.m. UTC 
From: Vishwanath Pai <vpai@akamai.com>

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>
---
 net/netfilter/ipset/ip_set_list_set.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
diff mbox

Patch

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 */