Disallow adding duplicate roots, toors, or other users w/uid 0.

Previously, a truth check instead if defined() check erroneously
allowed that.

PR:		bin/8745

1 files changed, 1 insertions, 1 deletions

diff --git a/usr.sbin/adduser/adduser.perl b/usr.sbin/adduser/adduser.perl
index 2728eff..2aa9c31 100644
--- a/usr.sbin/adduser/adduser.perl
+++ b/usr.sbin/adduser/adduser.perl
@@ -345,7 +345,7 @@ sub new_users_name_valid {
 	    warn "Username doesn't match the regexp /$usernameregexp/\a\n";
 	}
 	return 0;
-    } elsif ($username{$name}) {
+    } elsif (defined($username{$name})) {
 	warn "Username ``$name'' already exists!\a\n"; return 0;
     }
     return 1;