net: reject creation of netdev names with colons

colons are used as a separator in netdev device lookup in dev_ioctl.c

Specific functions are SIOCGIFTXQLEN SIOCETHTOOL SIOCSIFNAME

Signed-off-by: Matthew Thode <mthode@mthode.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 8f9710c..962ee9d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -946,7 +946,7 @@
 		return false;
 
 	while (*name) {
-		if (*name == '/' || isspace(*name))
+		if (*name == '/' || *name == ':' || isspace(*name))
 			return false;
 		name++;
 	}