rtnetlink: NUL-terminate IFLA_PHYS_PORT_NAME string

[ Upstream commit 77ef033b687c3e030017c94a29bf6ea3aaaef678 ]

IFLA_PHYS_PORT_NAME is a string attribute, so terminate it with \0.
Otherwise libnl3 fails to validate netlink messages with this attribute.
"ip -detail a" assumes too that the attribute is NUL-terminated when
printing it. It often was, due to padding.

I noticed this as libvirtd failing to start on a system with sfc driver
after upgrading it to Linux 4.11, i.e. when sfc added support for
phys_port_name.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index b7f9ae7..b490af6 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1059,7 +1059,7 @@ static int rtnl_phys_port_name_fill(struct sk_buff *skb, struct net_device *dev)
                return err;
        }
 
-       if (nla_put(skb, IFLA_PHYS_PORT_NAME, strlen(name), name))
+       if (nla_put_string(skb, IFLA_PHYS_PORT_NAME, name))
                return -EMSGSIZE;
 
        return 0;