examples.authorization.DigestServerAuthenticationMethod Maven / Gradle / Ivy

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package examples.authorization;

import java.security.*;
import java.util.*;

import javax.sip.*;
import javax.sip.message.*;
import javax.sip.header.*;
import javax.sip.address.*;

/**
 * Implements the HTTP digest authentication method.
 * @author M. Ranganathan
 * @author Marc Bednarek
 */
public class DigestServerAuthenticationMethod implements AuthenticationMethod {

    public static final String DEFAULT_SCHEME = "Digest";

    public static final String DEFAULT_DOMAIN = "127.0.0.1";

    public static final String DEFAULT_ALGORITHM = "MD5";

    public static String DEFAULT_REALM = "nist.gov";

    String USER_AUTH = "auth";

    String PASS_AUTH = "pass";

    private MessageDigest messageDigest;

    /** to hex converter */
    private static final char[] toHex = { '0', '1', '2', '3', '4', '5', '6',
            '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

    /**
     * Default constructor.
     */
    public DigestServerAuthenticationMethod() {
        try {
            messageDigest = MessageDigest.getInstance(DEFAULT_ALGORITHM);
        } catch (NoSuchAlgorithmException ex) {
            System.out.println("Algorithm not found " + ex);
            ex.printStackTrace();
        }
    }

    public static String toHexString(byte b[]) {
        int pos = 0;
        char[] c = new char[b.length * 2];
        for (int i = 0; i < b.length; i++) {
            c[pos++] = toHex[(b[i] >> 4) & 0x0F];
            c[pos++] = toHex[b[i] & 0x0f];
        }
        return new String(c);
    }

    /**
     * Initialize
     */
    public void initialize() {
        System.out.println("DEBUG, DigestAuthenticationMethod, initialize(),"
                + " the realm is:" + DEFAULT_REALM);
    }

    /**
     * Get the authentication scheme
     *
     * @return the scheme name
     */
    public String getScheme() {
        return DEFAULT_SCHEME;
    }

    /**
     * get the authentication realm
     *
     * @return the realm name
     */
    public String getRealm(String resource) {
        return DEFAULT_REALM;
    }

    /**
     * get the authentication domain.
     *
     * @return the domain name
     */
    public String getDomain() {
        return DEFAULT_DOMAIN;
    }

    /**
     * Get the authentication Algorithm
     *
     * @return the alogirithm name (i.e. Digest).
     */
    public String getAlgorithm() {
        return DEFAULT_ALGORITHM;
    }

    /**
     * Generate the challenge string.
     *
     * @return a generated nonce.
     */
    public String generateNonce() {
        // Get the time of day and run MD5 over it.
        Date date = new Date();
        long time = date.getTime();
        Random rand = new Random();
        long pad = rand.nextLong();
        String nonceString = (new Long(time)).toString()
                + (new Long(pad)).toString();
        byte mdbytes[] = messageDigest.digest(nonceString.getBytes());
        // Convert the mdbytes array into a hex string.
        return toHexString(mdbytes);
    }

    /**
     * Check the response and answer true if authentication succeeds. We are
     * making simplifying assumptions here and assuming that the password is
     * available to us for computation of the MD5 hash. We also dont cache
     * authentications so that the user has to authenticate on each
     * registration.
     *
     * @param user
     *            is the username
     * @param authHeader
     *            is the Authroization header from the SIP request.
     * @param requestLine
     *            is the SIP Request line from the SIP request.
     * @exception SIPAuthenticationException
     *                is thrown when authentication fails or message is bad
     */
    public boolean doAuthenticate(String user, AuthorizationHeader authHeader,
            Request request) {
        String realm = authHeader.getRealm();
        String username = authHeader.getUsername();
        URI requestURI = request.getRequestURI();

        if (username == null) {
            System.out
                    .println("DEBUG, DigestAuthenticateMethod, doAuthenticate(): "
                            + "WARNING: userName parameter not set in the header received!!!");
            username = user;
        }
        if (realm == null) {
            System.out
                    .println("DEBUG, DigestAuthenticateMethod, doAuthenticate(): "
                            + "WARNING: realm parameter not set in the header received!!! WE use the default one");
            realm = DEFAULT_REALM;
        }

        System.out
                .println("DEBUG, DigestAuthenticateMethod, doAuthenticate(): "
                        + "Trying to authenticate user: " + username + " for "
                        + " the realm: " + realm);

        String nonce = authHeader.getNonce();
        // If there is a URI parameter in the Authorization header,
        // then use it.
        URI uri = authHeader.getURI();
        // There must be a URI parameter in the authorization header.
        if (uri == null) {
            System.out
                    .println("DEBUG, DigestAuthenticateMethod, doAuthenticate(): "
                            + "ERROR: uri paramater not set in the header received!");
            return false;
        }
        System.out
                .println("DEBUG, DigestAuthenticationMethod, doAuthenticate(), username:"
                        + username + "!");
        System.out
                .println("DEBUG, DigestAuthenticationMethod, doAuthenticate(), realm:"
                        + realm + "!");
        System.out
                .println("DEBUG, DigestAuthenticationMethod, doAuthenticate(), password:"
                        + PASS_AUTH + "!");
        System.out
                .println("DEBUG, DigestAuthenticationMethod, doAuthenticate(), uri:"
                        + uri + "!");
        System.out
                .println("DEBUG, DigestAuthenticationMethod, doAuthenticate(), nonce:"
                        + nonce + "!");
        System.out
                .println("DEBUG, DigestAuthenticationMethod, doAuthenticate(), method:"
                        + request.getMethod() + "!");

        String A1 = username + ":" + realm + ":" + PASS_AUTH;
        String A2 = request.getMethod().toUpperCase() + ":" + uri.toString();
        byte mdbytes[] = messageDigest.digest(A1.getBytes());
        String HA1 = toHexString(mdbytes);

        System.out
                .println("DEBUG, DigestAuthenticationMethod, doAuthenticate(), HA1:"
                        + HA1 + "!");
        mdbytes = messageDigest.digest(A2.getBytes());
        String HA2 = toHexString(mdbytes);
        System.out
                .println("DEBUG, DigestAuthenticationMethod, doAuthenticate(), HA2:"
                        + HA2 + "!");
        String cnonce = authHeader.getCNonce();
        String KD = HA1 + ":" + nonce;
        if (cnonce != null) {
            KD += ":" + cnonce;
        }
        KD += ":" + HA2;
        mdbytes = messageDigest.digest(KD.getBytes());
        String mdString = toHexString(mdbytes);
        String response = authHeader.getResponse();
        System.out
                .println("DEBUG, DigestAuthenticateMethod, doAuthenticate(): "
                        + "we have to compare his response: " + response
                        + " with our computed" + " response: " + mdString);

        int res = (mdString.compareTo(response));
        if (res == 0) {
            System.out
                    .println("DEBUG, DigestAuthenticateMethod, doAuthenticate(): "
                            + "User authenticated...");
        } else {
            System.out
                    .println("DEBUG, DigestAuthenticateMethod, doAuthenticate(): "
                            + "User not authenticated...");
        }
        return res == 0;
    }

}