rtnetlink: verify rate parameters for calls to ndo_set_vf_rate

When calling ndo_set_vf_rate() the max_tx_rate parameter may be zero,
in which case the setting is cleared, or it must be greater or equal to
min_tx_rate.

Enforce this requirement on all calls to ndo_set_vf_rate via a wrapper
which also only calls ndo_set_vf_rate() if defined by the driver.

Based on work by Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Bin Chen <bin.chen@corigine.com>
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net/core/rtnetlink.c

@@ -2306,6 +2306,19 @@ static int rtnl_ensure_unique_netns(struct nlattr *tb[],
 	return -EINVAL;
 }
 
+static	int rtnl_set_vf_rate(struct net_device *dev, int vf, int min_tx_rate,
+			     int max_tx_rate)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+
+	if (!ops->ndo_set_vf_rate)
+		return -EOPNOTSUPP;
+	if (max_tx_rate && max_tx_rate < min_tx_rate)
+		return -EINVAL;
+
+	return ops->ndo_set_vf_rate(dev, vf, min_tx_rate, max_tx_rate);
+}
+
 static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[],
 			    struct netlink_ext_ack *extack)
 {
@@ -2443,11 +2456,8 @@ static int do_setvfinfo(struct net_device *dev, struct nlattr **tb)
 		if (err < 0)
 			return err;
 
-		err = -EOPNOTSUPP;
-		if (ops->ndo_set_vf_rate)
-			err = ops->ndo_set_vf_rate(dev, ivt->vf,
-						   ivf.min_tx_rate,
-						   ivt->rate);
+		err = rtnl_set_vf_rate(dev, ivt->vf,
+				       ivf.min_tx_rate, ivt->rate);
 		if (err < 0)
 			return err;
 	}
@@ -2457,11 +2467,9 @@ static int do_setvfinfo(struct net_device *dev, struct nlattr **tb)
 
 		if (ivt->vf >= INT_MAX)
 			return -EINVAL;
-		err = -EOPNOTSUPP;
-		if (ops->ndo_set_vf_rate)
-			err = ops->ndo_set_vf_rate(dev, ivt->vf,
-						   ivt->min_tx_rate,
-						   ivt->max_tx_rate);
+
+		err = rtnl_set_vf_rate(dev, ivt->vf,
+				       ivt->min_tx_rate, ivt->max_tx_rate);
 		if (err < 0)
 			return err;
 	}