Index: sbin/ifconfig/ifconfig.c
===================================================================
RCS file: /home/ncvs/src/sbin/ifconfig/ifconfig.c,v
retrieving revision 1.97
diff -u -r1.97 ifconfig.c
--- sbin/ifconfig/ifconfig.c	10 Mar 2004 08:42:53 -0000	1.97
+++ sbin/ifconfig/ifconfig.c	13 Mar 2004 00:04:40 -0000
@@ -1049,18 +1049,17 @@
 setifname(const char *val, int dummy __unused, int s, 
     const struct afswtch *afp)
 {
-	char	*newname;
+	char	newname[IFNAMSIZ];
 
-	newname = strdup(val);
+	if (sscanf(val, "%[a-zA-Z0-9_]", newname) != 1)
+		errx(-1, "setifname: invalid name specified!");
 
 	ifr.ifr_data = newname;
 	if (ioctl(s, SIOCSIFNAME, (caddr_t)&ifr) < 0) {
 		warn("ioctl (set name)");
-		free(newname);
 		return;
 	}
 	strlcpy(name, newname, sizeof(name));
-	free(newname);
 
 	/*
 	 * Even if we just created the interface, we don't need to print