diff -Nru a/net/core/dev.c b/net/core/dev.c
--- a/net/core/dev.c	Tue Jan 13 14:20:51 2004
+++ b/net/core/dev.c	Tue Jan 13 14:20:51 2004
@@ -621,6 +621,21 @@
 }
 
 /**
+ *	dev_valid_name - check if name is okay for network device
+ *	@name: name string
+ *
+ *	Network device names need to be valid file names to
+ *	to allow sysfs to work
+ */
+int dev_valid_name(const char *name)
+{
+	return !(*name == '\0' 
+		 || !strcmp(name, ".")
+		 || !strcmp(name, "..")
+		 || strchr(name, '/'));
+}
+
+/**
  *	dev_alloc_name - allocate a name for a device
  *	@dev: device
  *	@name: name format string
@@ -2685,6 +2723,11 @@
 				ret = -EIO;
 			goto out_err;
 		}
+	}
+ 
+	if (!dev_valid_name(dev->name)) {
+		ret = -EINVAL;
+		goto out_err;
 	}
 
 	dev->ifindex = dev_new_index();
diff -Nru a/net/core/dev.c b/net/core/dev.c
--- a/net/core/dev.c	Wed Jan 14 16:09:02 2004
+++ b/net/core/dev.c	Wed Jan 14 16:09:02 2004
@@ -718,7 +718,7 @@
 
 	if (strchr(newname, '%')) {
 		int err = dev_alloc_name(dev, newname);
-		if (err)
+		if (err < 0)
 			return err;
 		strcpy(newname, dev->name);
 	}