[PATCH net] openvswitch: fix send of uninitialized stack memory in ct limit reply

From: Ilya Maximets
Date: Sun Apr 04 2021 - 13:51:42 EST


'struct ovs_zone_limit' has more members than initialized in
ovs_ct_limit_get_default_limit(). The rest of the memory is a random
kernel stack content that ends up being sent to userspace.

Fix that by using designated initializer that will clear all
non-specified fields.

Fixes: 11efd5cb04a1 ("openvswitch: Support conntrack zone limit")
Signed-off-by: Ilya Maximets <i.maximets@xxxxxxx>
---
net/openvswitch/conntrack.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index c29b0ef1fc27..cadb6a29b285 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -2032,10 +2032,10 @@ static int ovs_ct_limit_del_zone_limit(struct nlattr *nla_zone_limit,
static int ovs_ct_limit_get_default_limit(struct ovs_ct_limit_info *info,
struct sk_buff *reply)
{
- struct ovs_zone_limit zone_limit;
-
- zone_limit.zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE;
- zone_limit.limit = info->default_limit;
+ struct ovs_zone_limit zone_limit = {
+ .zone_id = OVS_ZONE_LIMIT_DEFAULT_ZONE,
+ .limit = info->default_limit,
+ };

return nla_put_nohdr(reply, sizeof(zone_limit), &zone_limit);
}
--
2.26.2