Slightly tweaked from Olivier Fourdan's original version.
diff -up krb5-1.6.1/src/appl/gssftp/ftpd/ftpd.c.nullpointer krb5-1.6.1/src/appl/gssftp/ftpd/ftpd.c
--- krb5-1.6.1/src/appl/gssftp/ftpd/ftpd.c.nullpointer	2010-03-01 10:21:42.000000000 +0000
+++ krb5-1.6.1/src/appl/gssftp/ftpd/ftpd.c	2010-03-01 13:58:51.000000000 +0000
@@ -810,7 +810,7 @@ user(name)
 #ifdef USE_PAM
 		if (appl_pam_enabled(kcontext, "ftpd")) {
 			if (appl_pam_acct_mgmt(FTP_PAM_SERVICE, 0,
-					       pw->pw_name, "",
+					       name, "",
 					       hostname,
 					       NULL,
 					       FTP_PAM_SERVICE) != 0) {
@@ -1093,7 +1093,7 @@ pass(passwd)
 		 *   kpass fails and the user has no local password
 		 *   kpass fails and the provided password doesn't match pw
 		 */
-		if ((pw == NULL) ||
+		if ((pw == NULL) || (
 #ifdef USE_PAM
 		    appl_pam_enabled(kcontext, "ftpd") ?
 		    (appl_pam_authenticate(FTP_PAM_SERVICE, 0,
@@ -1105,7 +1105,7 @@ pass(passwd)
 		    (!kpass(pw->pw_name, passwd) &&
 		     (want_creds ||
 		      !*pw->pw_passwd ||
-		      strcmp(xpasswd, pw->pw_passwd)))) {
+		      strcmp(xpasswd, pw->pw_passwd))))) {
 			pw = NULL;
 			sleep(5);
 			if (++login_attempts >= 3) {