netlink: bug fix: don't overrun skbs on vf_port dump
Noticed by Patrick McHardy: was continuing to fill skb after a
nla_put_failure, ignoring the size calculated by upper layer. Now,
return -EMSGSIZE on any overruns, but also allow netdev to
fail ndo_get_vf_port with error other than -EMSGSIZE, thus unwinding
nest.
Signed-off-by: Scott Feldman <scofeldm@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 7ab86f3..7331bb2 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -722,14 +722,13 @@
for (vf = 0; vf < dev_num_vf(dev->dev.parent); vf++) {
vf_port = nla_nest_start(skb, IFLA_VF_PORT);
- if (!vf_port) {
- nla_nest_cancel(skb, vf_ports);
- return -EMSGSIZE;
- }
+ if (!vf_port)
+ goto nla_put_failure;
NLA_PUT_U32(skb, IFLA_PORT_VF, vf);
err = dev->netdev_ops->ndo_get_vf_port(dev, vf, skb);
+ if (err == -EMSGSIZE)
+ goto nla_put_failure;
if (err) {
-nla_put_failure:
nla_nest_cancel(skb, vf_port);
continue;
}
@@ -739,6 +738,10 @@
nla_nest_end(skb, vf_ports);
return 0;
+
+nla_put_failure:
+ nla_nest_cancel(skb, vf_ports);
+ return -EMSGSIZE;
}
static int rtnl_port_self_fill(struct sk_buff *skb, struct net_device *dev)
@@ -753,7 +756,7 @@
err = dev->netdev_ops->ndo_get_vf_port(dev, PORT_SELF_VF, skb);
if (err) {
nla_nest_cancel(skb, port_self);
- return err;
+ return (err == -EMSGSIZE) ? err : 0;
}
nla_nest_end(skb, port_self);