[PATCH net] macsec: restrict to ethernet devices

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

From: Willem de Bruijn <willemb@google.com>

Only attach macsec to ethernet devices.

Syzbot was able able trigger a KMSAN warning in macsec_handle_frame
by attaching to a phonet device.

Macvlan has a similar check in macvlan_port_create.

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
---
 drivers/net/macsec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 6ec6fc191a6e..92bc2b2df660 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -19,6 +19,7 @@
 #include <net/gro_cells.h>
 #include <net/macsec.h>
 #include <linux/phy.h>
+#include <linux/if_arp.h>
 
 #include <uapi/linux/if_macsec.h>
 
@@ -3665,6 +3666,8 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
 	real_dev = __dev_get_by_index(net, nla_get_u32(tb[IFLA_LINK]));
 	if (!real_dev)
 		return -ENODEV;
+	if (real_dev->type != ARPHRD_ETHER)
+		return -EINVAL;
 
 	dev->priv_flags |= IFF_MACSEC;
 
-- 
2.25.1.696.g5e7596f4ac-goog