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Commit 266e8347 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by David S. Miller
Browse files

macvlan: better mode validation 



macvlan passthrough mode is special: it's not possible to switch to or
from it through a netlink command.

But if you try, the command will succeed, which is
confusing.

Validate input and return error to user.

Cc:  Sridhar Samudrala <sri@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c756891a

drivers/net/macvlan.c

+14 −2
Original line number Diff line number Diff line
@@ -863,6 +863,18 @@ static int macvlan_changelink(struct net_device *dev, 
		struct nlattr *tb[], struct nlattr *data[])

{

	struct macvlan_dev *vlan = netdev_priv(dev);

	enum macvlan_mode mode;

	bool set_mode = false;



	/* Validate mode, but don't set yet: setting flags may fail. */

	if (data && data[IFLA_MACVLAN_MODE]) {

		set_mode = true;

		mode = nla_get_u32(data[IFLA_MACVLAN_MODE]);

		/* Passthrough mode can't be set or cleared dynamically */

		if ((mode == MACVLAN_MODE_PASSTHRU) !=

		    (vlan->mode == MACVLAN_MODE_PASSTHRU))

			return -EINVAL;

	}



	if (data && data[IFLA_MACVLAN_FLAGS]) {

		__u16 flags = nla_get_u16(data[IFLA_MACVLAN_FLAGS]);
@@ -879,8 +891,8 @@ static int macvlan_changelink(struct net_device *dev, 
		}

		vlan->flags = flags;

	}

	if (data && data[IFLA_MACVLAN_MODE])

		vlan->mode = nla_get_u32(data[IFLA_MACVLAN_MODE]);

	if (set_mode)

		vlan->mode = mode;

	return 0;

}