org.apache.sshd.server.keyprovider.AbstractGeneratorHostKeyProvider Maven / Gradle / Ivy
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* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.sshd.server.keyprovider;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.LinkOption;
import java.nio.file.OpenOption;
import java.nio.file.Path;
import java.security.GeneralSecurityException;
import java.security.InvalidKeyException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PublicKey;
import java.security.spec.AlgorithmParameterSpec;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.sshd.common.AlgorithmNameProvider;
import org.apache.sshd.common.NamedResource;
import org.apache.sshd.common.cipher.ECCurves;
import org.apache.sshd.common.config.keys.BuiltinIdentities;
import org.apache.sshd.common.config.keys.KeyUtils;
import org.apache.sshd.common.keyprovider.AbstractKeyPairProvider;
import org.apache.sshd.common.keyprovider.KeySizeIndicator;
import org.apache.sshd.common.session.SessionContext;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.io.IoUtils;
import org.apache.sshd.common.util.io.resource.PathResource;
import org.apache.sshd.common.util.security.SecurityUtils;
/**
* Holds a single {@link KeyPair} which is generated the 1st time {@link #loadKeys(SessionContext)} is called. If
* there is a file backing it up and the file exists, the key is loaded from it. Otherwise a new key pair is generated
* and saved (provided a path is configured and {@link #isOverwriteAllowed()}
*
* @author Apache MINA SSHD Project
*/
public abstract class AbstractGeneratorHostKeyProvider
extends AbstractKeyPairProvider
implements AlgorithmNameProvider, KeySizeIndicator {
public static final String DEFAULT_ALGORITHM = KeyUtils.EC_ALGORITHM;
public static final boolean DEFAULT_ALLOWED_TO_OVERWRITE = true;
private final AtomicReference> keyPairHolder = new AtomicReference<>();
private Path path;
private String algorithm = DEFAULT_ALGORITHM;
private int keySize;
private AlgorithmParameterSpec keySpec;
private boolean overwriteAllowed = DEFAULT_ALLOWED_TO_OVERWRITE;
protected AbstractGeneratorHostKeyProvider() {
super();
}
public Path getPath() {
return path;
}
public void setPath(Path path) {
this.path = (path == null) ? null : path.toAbsolutePath();
}
@Override
public String getAlgorithm() {
return algorithm;
}
public void setAlgorithm(String algorithm) {
this.algorithm = algorithm;
}
@Override
public int getKeySize() {
return keySize;
}
public void setKeySize(int keySize) {
this.keySize = keySize;
}
public AlgorithmParameterSpec getKeySpec() {
return keySpec;
}
public void setKeySpec(AlgorithmParameterSpec keySpec) {
this.keySpec = keySpec;
}
public boolean isOverwriteAllowed() {
return overwriteAllowed;
}
public void setOverwriteAllowed(boolean overwriteAllowed) {
this.overwriteAllowed = overwriteAllowed;
}
public void clearLoadedKeys() {
Iterable ids;
synchronized (keyPairHolder) {
ids = keyPairHolder.getAndSet(null);
}
if ((ids != null) & log.isDebugEnabled()) {
log.debug("clearLoadedKeys({}) removed keys", getPath());
}
}
@Override // co-variant return
public synchronized List loadKeys(SessionContext session) {
Path keyPath = getPath();
Iterable ids;
synchronized (keyPairHolder) {
ids = keyPairHolder.get();
if (ids == null) {
try {
ids = resolveKeyPairs(session, keyPath);
if (ids != null) {
keyPairHolder.set(ids);
}
} catch (Throwable t) {
warn("loadKeys({}) Failed ({}) to resolve: {}",
keyPath, t.getClass().getSimpleName(), t.getMessage(), t);
}
}
}
List pairs = Collections.emptyList();
if (ids instanceof List) {
pairs = (List) ids;
} else if (ids != null) {
pairs = new ArrayList<>();
for (KeyPair kp : ids) {
if (kp == null) {
continue;
}
pairs.add(kp);
}
}
return pairs;
}
protected Iterable resolveKeyPairs(SessionContext session, Path keyPath)
throws IOException, GeneralSecurityException {
String alg = getAlgorithm();
if (keyPath != null) {
try {
Iterable ids = loadFromFile(session, alg, keyPath);
KeyPair kp = GenericUtils.head(ids);
if (kp != null) {
return ids;
}
} catch (Throwable e) {
warn("resolveKeyPair({}) Failed ({}) to load: {}",
keyPath, e.getClass().getSimpleName(), e.getMessage(), e);
}
}
// either no file specified or no key in file
KeyPair kp = null;
try {
kp = generateKeyPair(alg);
if (kp == null) {
return null;
}
if (log.isDebugEnabled()) {
PublicKey key = kp.getPublic();
log.debug("resolveKeyPair({}) generated {} key={}-{}",
keyPath, alg, KeyUtils.getKeyType(key), KeyUtils.getFingerPrint(key));
}
} catch (Throwable e) {
warn("resolveKeyPair({})[{}] Failed ({}) to generate {} key-pair: {}",
keyPath, alg, e.getClass().getSimpleName(), alg, e.getMessage(), e);
return null;
}
if (keyPath != null) {
try {
writeKeyPair(kp, keyPath);
} catch (Throwable e) {
warn("resolveKeyPair({})[{}] Failed ({}) to write {} key: {}",
alg, keyPath, e.getClass().getSimpleName(), alg, e.getMessage(), e);
}
}
return Collections.singletonList(kp);
}
protected Iterable loadFromFile(SessionContext session, String alg, Path keyPath)
throws IOException, GeneralSecurityException {
LinkOption[] options = IoUtils.getLinkOptions(true);
if ((!Files.exists(keyPath, options)) || (!Files.isRegularFile(keyPath, options))) {
return null;
}
Iterable ids = readKeyPairs(session, keyPath, IoUtils.EMPTY_OPEN_OPTIONS);
KeyPair kp = GenericUtils.head(ids);
if (kp == null) {
return null;
}
// Assume all keys are of same type
PublicKey key = kp.getPublic();
String keyAlgorithm = key.getAlgorithm();
if (BuiltinIdentities.Constants.ECDSA.equalsIgnoreCase(keyAlgorithm)) {
keyAlgorithm = KeyUtils.EC_ALGORITHM;
} else if (BuiltinIdentities.Constants.ED25519.equalsIgnoreCase(keyAlgorithm)) {
keyAlgorithm = SecurityUtils.EDDSA;
}
if (Objects.equals(alg, keyAlgorithm)) {
if (log.isDebugEnabled()) {
log.debug("resolveKeyPair({}) loaded key={}-{}",
keyPath, KeyUtils.getKeyType(key), KeyUtils.getFingerPrint(key));
}
return ids;
}
// Not same algorithm - start again
if (log.isDebugEnabled()) {
log.debug("resolveKeyPair({}) mismatched loaded key algorithm: expected={}, loaded={}",
keyPath, alg, keyAlgorithm);
}
Files.deleteIfExists(keyPath);
return null;
}
protected Iterable readKeyPairs(SessionContext session, Path keyPath, OpenOption... options)
throws IOException, GeneralSecurityException {
PathResource location = new PathResource(keyPath, options);
try (InputStream inputStream = location.openInputStream()) {
return doReadKeyPairs(session, location, inputStream);
}
}
protected Iterable doReadKeyPairs(SessionContext session, NamedResource resourceKey, InputStream inputStream)
throws IOException, GeneralSecurityException {
return SecurityUtils.loadKeyPairIdentities(session, resourceKey, inputStream, null);
}
protected void writeKeyPair(KeyPair kp, Path keyPath, OpenOption... options)
throws IOException, GeneralSecurityException {
if ((!Files.exists(keyPath)) || isOverwriteAllowed()) {
PathResource location = new PathResource(keyPath); // The options are for write (!!)
try (OutputStream os = Files.newOutputStream(keyPath, options)) {
doWriteKeyPair(location, kp, os);
} catch (Throwable e) {
warn("writeKeyPair({}) failed ({}) to write key {}: {}",
keyPath, e.getClass().getSimpleName(), kp, e.getMessage(), e);
}
} else {
log.error("Overwriting key ({}) is disabled: using throwaway {}: {}",
keyPath, KeyUtils.getKeyType(kp), KeyUtils.getFingerPrint((kp == null) ? null : kp.getPublic()));
}
}
protected abstract void doWriteKeyPair(
NamedResource resourceKey, KeyPair kp, OutputStream outputStream)
throws IOException, GeneralSecurityException;
protected KeyPair generateKeyPair(String algorithm) throws GeneralSecurityException {
KeyPairGenerator generator = SecurityUtils.getKeyPairGenerator(algorithm);
if (keySpec != null) {
generator.initialize(keySpec);
log.info("generateKeyPair(" + algorithm + ") generating host key - spec=" + keySpec.getClass().getSimpleName());
} else if (KeyUtils.EC_ALGORITHM.equals(algorithm)) {
ECCurves curve;
// If left to our own devices choose the biggest key size possible
if (keySize == 0) {
int numCurves = ECCurves.SORTED_KEY_SIZE.size();
curve = ECCurves.SORTED_KEY_SIZE.get(numCurves - 1);
} else {
curve = ECCurves.fromCurveSize(keySize);
if (curve == null) {
throw new InvalidKeyException("No match found for curve with key size=" + keySize);
}
}
generator.initialize(curve.getParameters());
log.info("generateKeyPair(" + algorithm + ") generating host key=" + curve);
} else if (keySize != 0) {
generator.initialize(keySize);
log.info("generateKeyPair(" + algorithm + ") generating host key - size=" + keySize);
}
return generator.generateKeyPair();
}
}
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