[PATCH 3.10 085/268] drop_monitor: add missing call to genlmsg_end

Willy Tarreau
2017-06-19T18:34:13Z

From: Reiter Wolfgang <wr0112358@gmail.com>

commit 4200462d88f47f3759bdf4705f87e207b0f5b2e4 upstream.

Update nlmsg_len field with genlmsg_end to enable userspace processing
using nlmsg_next helper. Also adds error handling.

Signed-off-by: Reiter Wolfgang <wr0112358@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
net/core/drop_monitor.c | 33 ++++++++++++++++++++++++---------
1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index a974dfe..c0fcf0c 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -80,6 +80,7 @@ static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
struct nlattr *nla;
struct sk_buff *skb;
unsigned long flags;
+ void *msg_header;

al = sizeof(struct net_dm_alert_msg);
al += dm_hit_limit * sizeof(struct net_dm_drop_point);
@@ -87,17 +88,31 @@ static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)

skb = genlmsg_new(al, GFP_KERNEL);

- if (skb) {
- genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
- 0, NET_DM_CMD_ALERT);
- nla = nla_reserve(skb, NLA_UNSPEC,
- sizeof(struct net_dm_alert_msg));
- msg = nla_data(nla);
- memset(msg, 0, al);
- } else {
- mod_timer(&data->send_timer, jiffies + HZ / 10);
+ if (!skb)
+ goto err;
+
+ msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
+ 0, NET_DM_CMD_ALERT);
+ if (!msg_header) {
+ nlmsg_free(skb);
+ skb = NULL;
+ goto err;
+ }
+ nla = nla_reserve(skb, NLA_UNSPEC,
+ sizeof(struct net_dm_alert_msg));
+ if (!nla) {
+ nlmsg_free(skb);
+ skb = NULL;
+ goto err;
}
+ msg = nla_data(nla);
+ memset(msg, 0, al);
+ genlmsg_end(skb, msg_header);
+ goto out;

+err:
+ mod_timer(&data->send_timer, jiffies + HZ / 10);
+out:
spin_lock_irqsave(&data->lock, flags);
swap(data->skb, skb);
spin_unlock_irqrestore(&data->lock, flags);
--
2.8.0.rc2.1.gbe9624a