001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.camel.component.crypto.processor;
018    
019    import java.security.PublicKey;
020    import java.security.Signature;
021    import java.security.SignatureException;
022    import java.security.cert.Certificate;
023    
024    import org.apache.camel.Exchange;
025    import org.apache.camel.component.crypto.DigitalSignatureConfiguration;
026    import org.apache.camel.util.ExchangeHelper;
027    import org.apache.commons.codec.binary.Base64;
028    
029    import static org.apache.camel.component.crypto.DigitalSignatureConstants.SIGNATURE_PUBLIC_KEY_OR_CERT;
030    
031    /**
032     * <code>VerifyingProcessor</code>
033     */
034    public class VerifyingProcessor extends DigitalSignatureProcessor {
035    
036        public VerifyingProcessor(DigitalSignatureConfiguration configuration) {
037            super(configuration);
038        }
039    
040        public void process(Exchange exchange) throws Exception {
041            Signature signer = createSignatureService();
042            Certificate cert = getCertificate(exchange);
043            if (cert == null) {
044                PublicKey pk = getPublicKeyOrCertificateFromHeader(exchange, PublicKey.class, config.getPublicKey());
045                if (pk == null) {
046                    throw new IllegalStateException(String.format("Cannot verify signature as no Public Key or Certificate has been supplied."
047                            + " Either supply one in the route definition or via the message header '%s'", SIGNATURE_PUBLIC_KEY_OR_CERT));
048                }
049                signer.initVerify(pk);
050            } else {
051                signer.initVerify(cert);
052            }
053    
054            calculateSignature(exchange, signer);
055    
056            byte[] signature = getSignatureFromExchange(exchange);
057            if (!signer.verify(signature)) {
058                throw new SignatureException("Cannot verify signature of exchange");
059            }
060            clearMessageHeaders(exchange.getIn());
061        }
062    
063        private byte[] getSignatureFromExchange(Exchange exchange) throws Exception {
064            String encodedSignature = ExchangeHelper.getMandatoryHeader(exchange, config.getSignatureHeader(), String.class);
065            if (encodedSignature == null) {
066                throw new IllegalStateException("Cannot verify exchange as no " + config.getSignatureHeader() + " header is present.");
067            }
068            return new Base64().decode(encodedSignature);
069        }
070    
071        private Certificate getCertificate(Exchange exchange) throws Exception {
072            Certificate cert = config.getCertificate(getAlias(exchange));
073            return getPublicKeyOrCertificateFromHeader(exchange, Certificate.class, cert);
074        }
075    
076        private <T> T getPublicKeyOrCertificateFromHeader(Exchange exchange, Class<? extends T> verificationType, T defaultsTo) {
077            T pkOrCert = exchange.getIn().getHeader(SIGNATURE_PUBLIC_KEY_OR_CERT, verificationType);
078            if (pkOrCert == null) {
079                pkOrCert = defaultsTo;
080            }
081            return pkOrCert;
082        }
083    
084    }