com.google.gerrit.sshd.HostKeyProvider Maven / Gradle / Ivy
// Copyright (C) 2009 The Android Open Source Project
//
// Licensed 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 com.google.gerrit.sshd;
import com.google.common.flogger.FluentLogger;
import com.google.gerrit.server.config.SitePaths;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.ProvisionException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
import org.apache.sshd.common.config.keys.KeyUtils;
import org.apache.sshd.common.keyprovider.FileKeyPairProvider;
import org.apache.sshd.common.keyprovider.KeyPairProvider;
import org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider;
class HostKeyProvider implements Provider {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
private final SitePaths site;
@Inject
HostKeyProvider(SitePaths site) {
this.site = site;
}
@Override
public KeyPairProvider get() {
Path objKey = site.ssh_key;
Path rsaKey = site.ssh_rsa;
Path ecdsaKey_256 = site.ssh_ecdsa_256;
Path ecdsaKey_384 = site.ssh_ecdsa_384;
Path ecdsaKey_521 = site.ssh_ecdsa_521;
Path ed25519Key = site.ssh_ed25519;
final List stdKeys = new ArrayList<>(6);
if (Files.exists(rsaKey)) {
stdKeys.add(rsaKey);
}
if (Files.exists(ecdsaKey_256)) {
stdKeys.add(ecdsaKey_256);
}
if (Files.exists(ecdsaKey_384)) {
stdKeys.add(ecdsaKey_384);
}
if (Files.exists(ecdsaKey_521)) {
stdKeys.add(ecdsaKey_521);
}
if (Files.exists(ed25519Key)) {
stdKeys.add(ed25519Key);
}
if (Files.exists(objKey)) {
if (stdKeys.isEmpty()) {
SimpleGeneratorHostKeyProvider p = new SimpleGeneratorHostKeyProvider();
p.setAlgorithm(KeyUtils.RSA_ALGORITHM);
p.setPath(objKey.toAbsolutePath());
logger.atWarning().log(
"Defaulting to RSA algorithm for SSH key exchange."
+ "This is a weak security setting, consider changing it (see 'sshd.kex' documentation section).");
return p;
}
// Both formats of host key exist, we don't know which format
// should be authoritative. Complain and abort.
//
stdKeys.add(objKey);
throw new ProvisionException("Multiple host keys exist: " + stdKeys);
}
if (stdKeys.isEmpty()) {
throw new ProvisionException("No SSH keys under " + site.etc_dir);
}
FileKeyPairProvider kp = new FileKeyPairProvider();
kp.setPaths(stdKeys);
return kp;
}
}