Index: pw_util.c
===================================================================
--- pw_util.c	(révision 241912)
+++ pw_util.c	(copie de travail)
@@ -96,6 +96,7 @@
 #if 0
 	struct rlimit rlim;
 #endif
+	struct stat st;
 
 	if (dir == NULL) {
 		strcpy(passwd_dir, _PATH_ETC);
@@ -123,6 +124,14 @@
 		strcpy(masterpasswd, master);
 	}
 
+	if (stat(masterpasswd, &st) == -1)
+		return (-1);
+
+	if (S_ISDIR(st.st_mode)) {
+		errno = EISDIR;
+		return (-1);
+	}
+
 	/*
 	 * The code that follows is extremely disruptive to the calling
 	 * process, and is therefore disabled until someone can conceive