org.maodian.flyingcat.xmpp.codec.SASLCodec.java Source code

Introduction

Here is the source code for org.maodian.flyingcat.xmpp.codec.SASLCodec.java

Source

/*
 * Copyright 2013 - 2013 Cole Wen
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.maodian.flyingcat.xmpp.codec;

import java.nio.charset.StandardCharsets;

import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang3.StringUtils;
import org.maodian.flyingcat.xmpp.entity.Auth;
import org.maodian.flyingcat.xmpp.state.SASLError;
import org.maodian.flyingcat.xmpp.state.XmppException;
import org.springframework.stereotype.Component;

/**
 * @author Cole Wen
 *
 */
@Component
public class SASLCodec extends AbstractCodec {

    /* (non-Javadoc)
     * @see org.maodian.flyingcat.xmpp.codec.Decoder#decode(javax.xml.stream.XMLStreamReader)
     */
    @Override
    public Object decode(XMLStreamReader xmlsr) {
        String mechanism = xmlsr.getAttributeValue("", "mechanism");
        if (StringUtils.equals("PLAIN", mechanism)) {
            String base64Data = null;
            try {
                base64Data = xmlsr.getElementText();
            } catch (XMLStreamException e) {
                throw new RuntimeException(e);
            }

            if (!Base64.isBase64(base64Data)) {
                throw new XmppException(SASLError.INCORRECT_ENCODING);
            }

            byte[] value = Base64.decodeBase64(base64Data);
            String text = new String(value, StandardCharsets.UTF_8);

            // apply PLAIN SASL mechanism whose rfc locates at http://tools.ietf.org/html/rfc4616
            int[] nullPosition = { -1, -1 };
            int nullIndex = 0;
            for (int i = 0; i < text.length(); ++i) {
                if (text.codePointAt(i) == 0) {
                    // a malicious base64 value may contain more than two null character
                    if (nullIndex > 1) {
                        throw new XmppException(SASLError.MALFORMED_REQUEST);
                    }
                    nullPosition[nullIndex++] = i;
                }
            }

            if (nullPosition[0] == -1 || nullPosition[1] == -1) {
                throw new XmppException("The format is invalid", SASLError.MALFORMED_REQUEST);
            }
            String authzid = StringUtils.substring(text, 0, nullPosition[0]);
            String authcid = StringUtils.substring(text, nullPosition[0] + 1, nullPosition[1]);
            String password = StringUtils.substring(text, nullPosition[1] + 1);

            if (authzid.getBytes(StandardCharsets.UTF_8).length > 255
                    || authcid.getBytes(StandardCharsets.UTF_8).length > 255
                    || password.getBytes(StandardCharsets.UTF_8).length > 255) {
                throw new XmppException(
                        "authorization id, authentication id and password should be equal or less than 255 bytes",
                        SASLError.MALFORMED_REQUEST);
            }
            return new Auth(authzid, authcid, password);
        } else {
            throw new XmppException(SASLError.INVALID_MECHANISM).set("mechanism", mechanism);
        }
    }

    /* (non-Javadoc)
     * @see org.maodian.flyingcat.xmpp.codec.Encoder#encode(java.lang.Object, javax.xml.stream.XMLStreamWriter)
     */
    @Override
    public void encode(Object object, XMLStreamWriter xmlsw) throws XMLStreamException {
        // TODO Auto-generated method stub

    }

}