digestauthenticator.java

This temp directory is used by the JVM for temporary file storage. The JVM is configured to use thi

            // Try to reauthenticate using data cached by SSO.  If this fails,
            // either the original SSO logon was of DIGEST or SSL (which
            // we can't reauthenticate ourselves because there is no
            // cached username and password), or the realm denied
            // the user's reauthentication for some reason.
            // In either case we have to prompt the user for a logon
            if (reauthenticateFromSSO(ssoId, request))
                return true;
        }
        */

        // Validate any credentials already included with this request
        HttpServletRequest hreq =
            (HttpServletRequest) request.getRequest();
        HttpServletResponse hres =
            (HttpServletResponse) response.getResponse();
        String authorization = request.getAuthorization();
        if (authorization != null) {
            principal = findPrincipal(hreq, authorization, context.getRealm());
            if (principal != null) {
                String username = parseUsername(authorization);
                register(request, response, principal,
                         Constants.DIGEST_METHOD,
                         username, null);
                return (true);
            }
        }

        // Send an "unauthorized" response and an appropriate challenge

        // Next, generate a nOnce token (that is a token which is supposed
        // to be unique).
        String nOnce = generateNOnce(hreq);

        setAuthenticateHeader(hreq, hres, config, nOnce);
        hres.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
        //      hres.flushBuffer();
        return (false);

    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Parse the specified authorization credentials, and return the
     * associated Principal that these credentials authenticate (if any)
     * from the specified Realm.  If there is no such Principal, return
     * <code>null</code>.
     *
     * @param request HTTP servlet request
     * @param authorization Authorization credentials from this request
     * @param realm Realm used to authenticate Principals
     */
    protected static Principal findPrincipal(HttpServletRequest request,
                                             String authorization,
                                             Realm realm) {

        //System.out.println("Authorization token : " + authorization);
        // Validate the authorization credentials format
        if (authorization == null)
            return (null);
        if (!authorization.startsWith("Digest "))
            return (null);
        authorization = authorization.substring(7).trim();


        StringTokenizer commaTokenizer =
            new StringTokenizer(authorization, ",");

        String userName = null;
        String realmName = null;
        String nOnce = null;
        String nc = null;
        String cnonce = null;
        String qop = null;
        String uri = null;
        String response = null;
        String method = request.getMethod();

        while (commaTokenizer.hasMoreTokens()) {
            String currentToken = commaTokenizer.nextToken();
            int equalSign = currentToken.indexOf('=');
            if (equalSign < 0)
                return null;
            String currentTokenName =
                currentToken.substring(0, equalSign).trim();
            String currentTokenValue =
                currentToken.substring(equalSign + 1).trim();
            if ("username".equals(currentTokenName))
                userName = removeQuotes(currentTokenValue);
            if ("realm".equals(currentTokenName))
                realmName = removeQuotes(currentTokenValue);
            if ("nonce".equals(currentTokenName))
                nOnce = removeQuotes(currentTokenValue);
            if ("nc".equals(currentTokenName))
                nc = currentTokenValue;
            if ("cnonce".equals(currentTokenName))
                cnonce = removeQuotes(currentTokenValue);
            if ("qop".equals(currentTokenName))
                qop = removeQuotes(currentTokenValue);
            if ("uri".equals(currentTokenName))
                uri = removeQuotes(currentTokenValue);
            if ("response".equals(currentTokenName))
                response = removeQuotes(currentTokenValue);
        }

        if ( (userName == null) || (realmName == null) || (nOnce == null)
             || (uri == null) || (response == null) )
            return null;

        // Second MD5 digest used to calculate the digest :
        // MD5(Method + ":" + uri)
        String a2 = method + ":" + uri;
        //System.out.println("A2:" + a2);

        String md5a2 = md5Encoder.encode(md5Helper.digest(a2.getBytes()));

        return (realm.authenticate(userName, response, nOnce, nc, cnonce, qop,
                                   realmName, md5a2));

    }


    /**
     * Parse the username from the specified authorization string.  If none
     * can be identified, return <code>null</code>
     *
     * @param authorization Authorization string to be parsed
     */
    protected String parseUsername(String authorization) {

        //System.out.println("Authorization token : " + authorization);
        // Validate the authorization credentials format
        if (authorization == null)
            return (null);
        if (!authorization.startsWith("Digest "))
            return (null);
        authorization = authorization.substring(7).trim();

        StringTokenizer commaTokenizer =
            new StringTokenizer(authorization, ",");

        while (commaTokenizer.hasMoreTokens()) {
            String currentToken = commaTokenizer.nextToken();
            int equalSign = currentToken.indexOf('=');
            if (equalSign < 0)
                return null;
            String currentTokenName =
                currentToken.substring(0, equalSign).trim();
            String currentTokenValue =
                currentToken.substring(equalSign + 1).trim();
            if ("username".equals(currentTokenName))
                return (removeQuotes(currentTokenValue));
        }

        return (null);

    }


    /**
     * Removes the quotes on a string.
     */
    protected static String removeQuotes(String quotedString) {
        if (quotedString.length() > 2) {
            return quotedString.substring(1, quotedString.length() - 1);
        } else {
            return new String();
        }
    }


    /**
     * Generate a unique token. The token is generated according to the
     * following pattern. NOnceToken = Base64 ( MD5 ( client-IP ":"
     * time-stamp ":" private-key ) ).
     *
     * @param request HTTP Servlet request
     */
    protected String generateNOnce(HttpServletRequest request) {

        long currentTime = System.currentTimeMillis();

        String nOnceValue = request.getRemoteAddr() + ":" +
            currentTime + ":" + key;

        byte[] buffer = md5Helper.digest(nOnceValue.getBytes());
        nOnceValue = md5Encoder.encode(buffer);

        // Updating the value in the no once hashtable
        nOnceTokens.put(nOnceValue, new Long(currentTime + nOnceTimeout));

        return nOnceValue;
    }


    /**
     * Generates the WWW-Authenticate header.
     * <p>
     * The header MUST follow this template :
     * <pre>
     *      WWW-Authenticate    = "WWW-Authenticate" ":" "Digest"
     *                            digest-challenge
     *
     *      digest-challenge    = 1#( realm | [ domain ] | nOnce |
     *                  [ digest-opaque ] |[ stale ] | [ algorithm ] )
     *
     *      realm               = "realm" "=" realm-value
     *      realm-value         = quoted-string
     *      domain              = "domain" "=" <"> 1#URI <">
     *      nonce               = "nonce" "=" nonce-value
     *      nonce-value         = quoted-string
     *      opaque              = "opaque" "=" quoted-string
     *      stale               = "stale" "=" ( "true" | "false" )
     *      algorithm           = "algorithm" "=" ( "MD5" | token )
     * </pre>
     *
     * @param request HTTP Servlet request
     * @param response HTTP Servlet response
     * @param config    Login configuration describing how authentication
     *              should be performed
     * @param nOnce nonce token
     */
    protected void setAuthenticateHeader(HttpServletRequest request,
                                         HttpServletResponse response,
                                         LoginConfig config,
                                         String nOnce) {

        // Get the realm name
        String realmName = config.getRealmName();
        if (realmName == null)
            realmName = request.getServerName() + ":"
                + request.getServerPort();

        byte[] buffer = md5Helper.digest(nOnce.getBytes());

        String authenticateHeader = "Digest realm=\"" + realmName + "\", "
            +  "qop=\"auth\", nonce=\"" + nOnce + "\", " + "opaque=\""
            + md5Encoder.encode(buffer) + "\"";
        // System.out.println("Authenticate header value : "
        //                   + authenticateHeader);
        response.setHeader("WWW-Authenticate", authenticateHeader);

    }


}