rtnetlink: NUL-terminate IFLA_PHYS_PORT_NAME string

michich · davem330 · commit 77ef033b687c · 2017-05-04T11:23:59.000-04:00
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 &lt;mschmidt@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
@@ -1054,7 +1054,7 @@ 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;

Original file line number	Diff line number	Diff line change
`@@ -1054,7 +1054,7 @@ static int rtnl_phys_port_name_fill(struct sk_buff skb, struct net_device dev)`
`1054`	`1054`	`return err;`
`1055`	`1055`	`}`
`1056`	`1056`
`1057`		`- if (nla_put(skb, IFLA_PHYS_PORT_NAME, strlen(name), name))`
	`1057`	`+ if (nla_put_string(skb, IFLA_PHYS_PORT_NAME, name))`
`1058`	`1058`	`return -EMSGSIZE;`
`1059`	`1059`
`1060`	`1060`	`return 0;`