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package com.sun.enterprise.security.auth.realm;

import com.sun.enterprise.security.auth.digest.impl.DigestProcessor;
import com.sun.enterprise.security.auth.digest.api.Password;
import com.sun.enterprise.security.auth.digest.impl.KeyDigestAlgoParamImpl;
import com.sun.enterprise.security.auth.digest.api.DigestAlgorithmParameter;
import com.sun.enterprise.security.auth.digest.api.Key;
import com.sun.enterprise.security.auth.digest.api.NestedDigestAlgoParam;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.spec.AlgorithmParameterSpec;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.catalina.util.MD5Encoder;
import static com.sun.enterprise.security.auth.digest.api.Constants.*;

/**
 * Base class for all realms wanting to support Digest based authentication.
 * @author K.Venugopal@sun.com
 */
public abstract class DigestRealmBase extends IASRealm implements DigestRealm {

    private DigestValidatorImpl validator = null;

    public DigestRealmBase() {
    }


    protected final boolean validate(final Password passwd, DigestAlgorithmParameter[] params) {
        try {
            return new DigestValidatorImpl().validate(passwd, params);
        } catch (NoSuchAlgorithmException ex) {            
            _logger.log(Level.SEVERE,"invalid.digest.algo",ex);
        }
        return false;
    }


    private class DigestValidatorImpl extends DigestProcessor {

        private Realm realm = null;
        private DigestAlgorithmParameter data = null;
        private DigestAlgorithmParameter clientResponse = null;
        private DigestAlgorithmParameter key = null;
        private String algorithm = "MD5";
        private String realmName = null;
        

        DigestValidatorImpl() {
           
        }

        protected final boolean validate(Password passwd, DigestAlgorithmParameter[] params) throws NoSuchAlgorithmException {

             for (int i = 0; i < params.length; i++) {
                DigestAlgorithmParameter dap = params[i];
                if (A1.equals(dap.getName()) && (dap instanceof Key)) {
                    key = dap;
                } else if (RESPONSE.equals(dap.getName())) {
                    clientResponse = dap;
                } else {
                    data = dap;
                }
            }
            setPassword(passwd);
            
            try {
                byte[] p1 = valueOf(key);
                byte[] p2 = valueOf(data);
                java.io.ByteArrayOutputStream bos = new java.io.ByteArrayOutputStream();
                bos.write(p1);
                bos.write(":".getBytes());
                bos.write(p2);

                MessageDigest md = MessageDigest.getInstance(algorithm);
                byte[] derivedKey = null;
                byte[] dk = md.digest(bos.toByteArray());
                String tmp = new MD5Encoder().encode(dk);
                derivedKey = tmp.getBytes();
                byte[] suppliedKey = clientResponse.getValue();
                boolean result = true;
                if (derivedKey.length == suppliedKey.length) {
                    for (int i = 0; i < derivedKey.length; i++) {
                        if (!(derivedKey[i] == suppliedKey[i])) {
                            result = false;
                            break;
                        }
                    }
                } else {
                    result = false;
                }
                return result;
            } catch (IOException ex) {
                Object[] msg =new String[1];
                msg[0]=ex.getMessage();                
               _logger.log(Level.SEVERE,"digest.error",msg);
            }
            return false;
        }
    }
}
