org.apache.sshd.client.config.hosts.KnownHostHashValue Maven / Gradle / Ivy
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* 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.client.config.hosts;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Base64;
import java.util.Objects;
import org.apache.sshd.common.Factory;
import org.apache.sshd.common.NamedFactory;
import org.apache.sshd.common.NamedResource;
import org.apache.sshd.common.RuntimeSshException;
import org.apache.sshd.common.SshConstants;
import org.apache.sshd.common.mac.Mac;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.NumberUtils;
import org.apache.sshd.common.util.ValidateUtils;
import org.apache.sshd.common.util.buffer.BufferUtils;
/**
* @author Apache MINA SSHD Project
*/
public class KnownHostHashValue {
/**
* Character used to indicate a hashed host pattern
*/
public static final char HASHED_HOST_DELIMITER = '|';
public static final NamedFactory DEFAULT_DIGEST = KnownHostDigest.SHA1;
private NamedFactory digester = DEFAULT_DIGEST;
private byte[] saltValue;
private byte[] digestValue;
public KnownHostHashValue() {
super();
}
public NamedFactory getDigester() {
return digester;
}
public void setDigester(NamedFactory digester) {
this.digester = digester;
}
public byte[] getSaltValue() {
return saltValue;
}
public void setSaltValue(byte[] saltValue) {
this.saltValue = saltValue;
}
public byte[] getDigestValue() {
return digestValue;
}
public void setDigestValue(byte[] digestValue) {
this.digestValue = digestValue;
}
/**
* Checks if the host matches the hash
*
* @param host The host name/address - ignored if {@code null}/empty
* @param port The access port - ignored if non-positive or SSH default
* @return {@code true} if host matches the hash
* @throws RuntimeException If entry not properly initialized
*/
public boolean isHostMatch(String host, int port) {
if (GenericUtils.isEmpty(host)) {
return false;
}
try {
byte[] expected = getDigestValue();
byte[] actual = calculateHashValue(host, port, getDigester(), getSaltValue());
return Arrays.equals(expected, actual);
} catch (Throwable t) {
if (t instanceof RuntimeException) {
throw (RuntimeException) t;
}
throw new RuntimeSshException(
"Failed (" + t.getClass().getSimpleName() + ")" + " to calculate hash value: " + t.getMessage(), t);
}
}
@Override
public String toString() {
if ((getDigester() == null) || NumberUtils.isEmpty(getSaltValue()) || NumberUtils.isEmpty(getDigestValue())) {
return Objects.toString(getDigester(), null)
+ "-" + BufferUtils.toHex(':', getSaltValue())
+ "-" + BufferUtils.toHex(':', getDigestValue());
}
try {
return append(new StringBuilder(Byte.MAX_VALUE), this).toString();
} catch (IOException | RuntimeException e) { // unexpected
return e.getClass().getSimpleName() + ": " + e.getMessage();
}
}
// see http://nms.lcs.mit.edu/projects/ssh/README.hashed-hosts
public static byte[] calculateHashValue(String host, int port, Factory factory, byte[] salt)
throws Exception {
return calculateHashValue(host, port, factory.create(), salt);
}
public static byte[] calculateHashValue(String host, int port, Mac mac, byte[] salt) throws Exception {
mac.init(salt);
String hostPattern = createHostPattern(host, port);
byte[] hostBytes = hostPattern.getBytes(StandardCharsets.UTF_8);
mac.update(hostBytes);
return mac.doFinal();
}
public static String createHostPattern(String host, int port) {
if (SshConstants.TO_EFFECTIVE_PORT.applyAsInt(port) == SshConstants.DEFAULT_PORT) {
return host;
}
try {
return appendHostPattern(new StringBuilder(host.length() + 8 /* port if necessary */), host, port).toString();
} catch (IOException e) {
throw new RuntimeException(
"Unexpected (" + e.getClass().getSimpleName() + ") failure" + " to generate host pattern of " + host + ":"
+ port + ": " + e.getMessage(),
e);
}
}
public static A appendHostPattern(A sb, String host, int port) throws IOException {
boolean nonDefaultPort = SshConstants.TO_EFFECTIVE_PORT.applyAsInt(port) != SshConstants.DEFAULT_PORT;
if (nonDefaultPort) {
sb.append(HostPatternsHolder.NON_STANDARD_PORT_PATTERN_ENCLOSURE_START_DELIM);
}
sb.append(host);
if (nonDefaultPort) {
sb.append(HostPatternsHolder.NON_STANDARD_PORT_PATTERN_ENCLOSURE_END_DELIM);
sb.append(HostPatternsHolder.PORT_VALUE_DELIMITER);
sb.append(Integer.toString(port));
}
return sb;
}
public static A append(A sb, KnownHostHashValue hashValue) throws IOException {
return (hashValue == null)
? sb : append(sb, hashValue.getDigester(), hashValue.getSaltValue(), hashValue.getDigestValue());
}
public static A append(A sb, NamedResource factory, byte[] salt, byte[] digest) throws IOException {
Base64.Encoder encoder = Base64.getEncoder();
sb.append(HASHED_HOST_DELIMITER).append(factory.getName());
sb.append(HASHED_HOST_DELIMITER).append(encoder.encodeToString(salt));
sb.append(HASHED_HOST_DELIMITER).append(encoder.encodeToString(digest));
return sb;
}
public static KnownHostHashValue parse(String patternString) {
String pattern = GenericUtils.replaceWhitespaceAndTrim(patternString);
return parse(pattern, GenericUtils.isEmpty(pattern) ? null : new KnownHostHashValue());
}
public static V parse(String patternString, V value) {
String pattern = GenericUtils.replaceWhitespaceAndTrim(patternString);
if (GenericUtils.isEmpty(pattern)) {
return value;
}
String[] components = GenericUtils.split(pattern, HASHED_HOST_DELIMITER);
ValidateUtils.checkTrue(components.length == 4 /* 1st one is empty */, "Invalid hash pattern (insufficient data): %s",
pattern);
ValidateUtils.checkTrue(GenericUtils.isEmpty(components[0]), "Invalid hash pattern (unexpected extra data): %s",
pattern);
NamedFactory factory = ValidateUtils.checkNotNull(KnownHostDigest.fromName(components[1]),
"Invalid hash pattern (unknown digest): %s", pattern);
Base64.Decoder decoder = Base64.getDecoder();
value.setDigester(factory);
value.setSaltValue(decoder.decode(components[2]));
value.setDigestValue(decoder.decode(components[3]));
return value;
}
}