/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.sshd.common.config.keys;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.StreamCorruptedException;
import java.security.GeneralSecurityException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.util.Collection;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.NumberUtils;
import org.apache.sshd.common.util.ValidateUtils;
/**
* Represents a decoder of an {@code OpenSSH} encoded key data
*
* @param <PUB> Type of {@link PublicKey}
* @param <PRV> Type of {@link PrivateKey}
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public interface PublicKeyEntryDecoder<PUB extends PublicKey, PRV extends PrivateKey>
extends KeyEntryResolver<PUB, PRV>, PublicKeyEntryResolver {
@Override
default PublicKey resolve(String keyType, byte[] keyData) throws IOException, GeneralSecurityException {
ValidateUtils.checkNotNullAndNotEmpty(keyType, "No key type provided");
Collection<String> supported = getSupportedTypeNames();
if ((GenericUtils.size(supported) > 0) && supported.contains(keyType)) {
return decodePublicKey(keyData);
}
throw new InvalidKeySpecException("resolve(" + keyType + ") not in listed supported types: " + supported);
}
/**
* @param keyData The key data bytes in {@code OpenSSH} format (after
* BASE64 decoding) - ignored if {@code null}/empty
* @return The decoded {@link PublicKey} - or {@code null} if no data
* @throws IOException If failed to decode the key
* @throws GeneralSecurityException If failed to generate the key
*/
default PUB decodePublicKey(byte... keyData) throws IOException, GeneralSecurityException {
return decodePublicKey(keyData, 0, NumberUtils.length(keyData));
}
default PUB decodePublicKey(byte[] keyData, int offset, int length) throws IOException, GeneralSecurityException {
if (length <= 0) {
return null;
}
try (InputStream stream = new ByteArrayInputStream(keyData, offset, length)) {
return decodePublicKey(stream);
}
}
default PUB decodePublicKey(InputStream keyData) throws IOException, GeneralSecurityException {
// the actual data is preceded by a string that repeats the key type
String type = KeyEntryResolver.decodeString(keyData);
if (GenericUtils.isEmpty(type)) {
throw new StreamCorruptedException("Missing key type string");
}
Collection<String> supported = getSupportedTypeNames();
if (GenericUtils.isEmpty(supported) || (!supported.contains(type))) {
throw new InvalidKeySpecException("Reported key type (" + type + ") not in supported list: " + supported);
}
return decodePublicKey(type, keyData);
}
/**
* @param keyType The reported / encode key type
* @param keyData The key data bytes stream positioned after the key type decoding
* and making sure it is one of the supported types
* @return The decoded {@link PublicKey}
* @throws IOException If failed to read from the data stream
* @throws GeneralSecurityException If failed to generate the key
*/
PUB decodePublicKey(String keyType, InputStream keyData) throws IOException, GeneralSecurityException;
/**
* Encodes the {@link PublicKey} using the {@code OpenSSH} format - same
* one used by the {@code decodePublicKey} method(s)
*
* @param s The {@link OutputStream} to write the data to
* @param key The {@link PublicKey} - may not be {@code null}
* @return The key type value - one of the {@link #getSupportedTypeNames()}
* @throws IOException If failed to generate the encoding
*/
String encodePublicKey(OutputStream s, PUB key) throws IOException;
}