PAMTest.java

/**
 * Can download libpam4j and JNA jars from:
 * http://mvnrepository.com/artifact/org.kohsuke/libpam4j
 * https://github.com/twall/jna
 * https://github.com/matthiasblaesing/libpam4j/commits/gc_and_threadsave
 *
 * SETUP: useradd zuser1 ; echo zuser1:password | chpasswd ; useradd zuser2 ; echo zuser2:password | chpasswd
 * BUILD 1.8: javac -classpath ./jna-4.0.0.jar:./libpam4j-1.8.jar:. PAMTest.java
 * BUILD 1.9X: javac -classpath ./jna-4.1.0.jar:./libpam4j-1.9X.jar:. PAMTest.java
 * FAILS:  sudo java -classpath ./jna-4.0.0.jar:./libpam4j-1.8.jar:. PAMTest zuser1:password zuser2:password
 * SUCCEEDS:  sudo java -classpath ./jna-4.1.0.jar:./libpam4j-1.9X.jar:. PAMTest zuser1:password zuser2:password
 */
import java.util.Collection;
import java.util.Optional;
import java.util.Set;
import java.util.Map;
import java.util.HashMap;
import java.util.HashSet;
import java.util.concurrent.*;

import org.jvnet.libpam.PAM;
import org.jvnet.libpam.UnixUser;

public class PAMTest {

    public static String getRandom (Set<String> e) {
        return e.stream()
            .skip((int) (e.size() * Math.random()))
            .findFirst().get();
    }
    public static void main(String[] argv) {
        if (argv.length == 0) {
            System.err.println("Time PAM authentication with: PAMTest user1:password1 user2:password2");
            System.exit(1);
        }
        String rando = null;
        try {
            Map<String,String> users = new HashMap<String,String>(argv.length);
            for (int i = 0; i < argv.length; ++i) {
                String[] parts = argv[i].split(":");
                if (parts.length != 2) {
                    System.err.println("Expected arguments with username:password, not " + argv[i]);
                    System.exit(1);
                }
                users.put(parts[0], parts[1]);
            }
            Set<String> userNames = users.keySet();
            Set<UnixUser> allUsers = new HashSet<UnixUser>();
            PAM pam = null;
            int counter = 0;
            while (true) {
                rando = getRandom(userNames);
                try {
                long fullstart = System.currentTimeMillis();
                if (pam == null) {
                    pam = new PAM("login");
                }
                long start = System.currentTimeMillis();
                UnixUser u = pam.authenticate(rando, users.get(rando));
                System.out.println("DEBUG: pam.authenticate=" + (System.currentTimeMillis() - start) + "ms / " + (System.currentTimeMillis() - fullstart) + "ms, User " + u.getUserName() + " " + u.getUID() + " " + u.getGID() + " " + u.getDir() + " " + u.getGecos() + " " + u.getShell() + " in " + u.getGroups());
                allUsers.add(u);
	        } catch (Exception e) {
	            System.out.println("Exception for user '" + rando + "', wrong password? " + e);
	            e.printStackTrace();
                throw e;
            } finally {
                    if (pam != null && ++counter % 10 == 0) {
                        long start = System.currentTimeMillis();
                        pam.dispose();
                        pam = null;
                        System.out.println("DISPOSE: " + (System.currentTimeMillis() - start));
                    }
                }
		/*
                int count = 0;
                for (UnixUser u : allUsers) {
                    System.out.println("DEBUG: " + ++count + ". user: " + u);
                    System.out.println("DEBUG:    " + u.getUserName() + " " + u.getUID() + " " + u.getGID() + " " + u.getDir() + " " + u.getGecos() + " " + u.getShell() + " in " + u.getGroups());
                }
		*/
            }
        } catch (Exception e) {
            System.out.println("Exception for user '" + rando + "', wrong password? " + e);
            e.printStackTrace();
            System.exit(1);
        }
        System.exit(0);
    }
}