===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/su/su.c,v
retrieving revision 1.77.2.1
retrieving revision 1.77.2.2
diff -u -r1.77.2.1 -r1.77.2.2
--- src/usr.bin/su/su.c	2019/12/04 09:52:22	1.77.2.1
+++ src/usr.bin/su/su.c	2019/12/09 04:50:42	1.77.2.2
@@ -1,4 +1,4 @@
-/*	$OpenBSD: su.c,v 1.77.2.1 2019/12/04 09:52:22 deraadt Exp $	*/
+/*	$OpenBSD: su.c,v 1.77.2.2 2019/12/09 04:50:42 tb Exp $	*/
 
 /*
  * Copyright (c) 1988 The Regents of the University of California.
@@ -172,6 +172,8 @@
 		err(1, "unveil");
 
 	for (;;) {
+		char *pw_class = class;
+
 		/* get target user, default to root unless in -L mode */
 		if (*argv) {
 			user = *argv;
@@ -207,11 +209,11 @@
 		}
 
 		/* If the user specified a login class, use it */
-		if (!class && pwd && pwd->pw_class && pwd->pw_class[0] != '\0')
-			class = strdup(pwd->pw_class);
-		if ((lc = login_getclass(class)) == NULL)
+		if (pw_class == NULL && pwd != NULL)
+			pw_class = pwd->pw_class;
+		if ((lc = login_getclass(pw_class)) == NULL)
 			auth_errx(as, 1, "no such login class: %s",
-			    class ? class : LOGIN_DEFCLASS);
+			    pw_class ? pw_class : LOGIN_DEFCLASS);
 
 		if ((ruid == 0 && !emlogin) ||
 		    verify_user(username, pwd, style, lc, as) == 0)