org.apache.sshd.common.signature.AbstractSignature Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* 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.signature;
import java.nio.charset.StandardCharsets;
import java.security.GeneralSecurityException;
import java.security.Key;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SignatureException;
import java.util.AbstractMap.SimpleImmutableEntry;
import java.util.Collection;
import java.util.Map;
import java.util.Objects;
import java.util.function.Predicate;
import org.apache.sshd.common.session.SessionContext;
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;
import org.apache.sshd.common.util.security.SecurityUtils;
/**
* Useful base class for {@link Signature} implementation
*
* @author Apache MINA SSHD Project
*/
public abstract class AbstractSignature implements Signature {
private java.security.Signature signatureInstance;
private final String algorithm;
protected AbstractSignature(String algorithm) {
this.algorithm = ValidateUtils.checkNotNullAndNotEmpty(algorithm, "No signature algorithm specified");
}
@Override
public final String getAlgorithm() {
return algorithm;
}
/**
* Initializes the internal signature instance
*
* @param session The {@link SessionContext} for calling this method - may be {@code null} if not
* called within a session context
* @param algo The signature's algorithm name
* @param key the {@link Key} that is provided for initialization - a {@link PrivateKey} for
* signing and a {@link PublicKey} for verification
* @param forSigning If {@code true} then it is being initialized for signing, otherwise for
* verifying a signature
* @return The {@link java.security.Signature} instance
* @throws GeneralSecurityException if failed to initialize
*/
protected java.security.Signature doInitSignature(
SessionContext session, String algo, Key key, boolean forSigning)
throws GeneralSecurityException {
return SecurityUtils.getSignature(algo);
}
/**
* @return The current {@link java.security.Signature} instance - {@code null} if not initialized
* @see #doInitSignature(SessionContext, String, Key, boolean)
*/
protected java.security.Signature getSignature() {
return signatureInstance;
}
@Override
public byte[] sign(SessionContext session) throws Exception {
java.security.Signature signature = Objects.requireNonNull(getSignature(), "Signature not initialized");
return signature.sign();
}
@Override
public void initVerifier(SessionContext session, PublicKey key) throws Exception {
String algo = getAlgorithm();
signatureInstance = Objects.requireNonNull(
doInitSignature(session, algo, key, false), "No signature instance create");
signatureInstance.initVerify(Objects.requireNonNull(key, "No public key provided"));
}
@Override
public void initSigner(SessionContext session, PrivateKey key) throws Exception {
String algo = getAlgorithm();
signatureInstance = Objects.requireNonNull(
doInitSignature(session, algo, key, true), "No signature instance create");
signatureInstance.initSign(Objects.requireNonNull(key, "No private key provided"));
}
@Override
public void update(SessionContext session, byte[] hash, int off, int len) throws Exception {
java.security.Signature signature = Objects.requireNonNull(getSignature(), "Signature not initialized");
signature.update(hash, off, len);
}
/**
* Makes an attempt to detect if the signature is encoded or pure data
*
* @param sig The original signature
* @param expectedTypes The expected encoded key types
* @return A {@link SimpleImmutableEntry} where first value is the key type and second value is the
* data - {@code null} if not encoded
*/
protected Map.Entry extractEncodedSignature(byte[] sig, Collection expectedTypes) {
return GenericUtils.isEmpty(expectedTypes) ? null : extractEncodedSignature(sig, expectedTypes::contains);
}
protected Map.Entry extractEncodedSignature(byte[] sig, Predicate typeSelector) {
int dataLen = NumberUtils.length(sig);
// if it is encoded then we must have at least 2 UINT32 values
if (dataLen < (2 * Integer.BYTES)) {
return null;
}
long keyTypeLen = BufferUtils.getUInt(sig, 0, dataLen);
// after the key type we MUST have data bytes
if (keyTypeLen >= (dataLen - Integer.BYTES)) {
return null;
}
int keyTypeStartPos = Integer.BYTES;
int keyTypeEndPos = keyTypeStartPos + (int) keyTypeLen;
int remainLen = dataLen - keyTypeEndPos;
// must have UINT32 with the data bytes length
if (remainLen < Integer.BYTES) {
return null;
}
long dataBytesLen = BufferUtils.getUInt(sig, keyTypeEndPos, remainLen);
// make sure reported number of bytes does not exceed available
if (dataBytesLen > (remainLen - Integer.BYTES)) {
return null;
}
String keyType = new String(sig, keyTypeStartPos, (int) keyTypeLen, StandardCharsets.UTF_8);
if (!typeSelector.test(keyType)) {
return null;
}
byte[] data = new byte[(int) dataBytesLen];
System.arraycopy(sig, keyTypeEndPos + Integer.BYTES, data, 0, (int) dataBytesLen);
return new SimpleImmutableEntry<>(keyType, data);
}
protected boolean doVerify(byte[] data) throws SignatureException {
java.security.Signature signature = Objects.requireNonNull(getSignature(), "Signature not initialized");
return signature.verify(data);
}
@Override
public String toString() {
return getClass().getSimpleName() + "[" + getAlgorithm() + "]";
}
}