Java tutorial
/* * 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.jclouds.digitalocean2.ssh; import static com.google.common.base.Joiner.on; import static com.google.common.base.Preconditions.checkArgument; import static com.google.common.base.Splitter.fixedLength; import static com.google.common.base.Throwables.propagate; import static com.google.common.collect.Iterables.get; import static com.google.common.collect.Iterables.size; import static com.google.common.io.BaseEncoding.base16; import static com.google.common.io.BaseEncoding.base64; import static org.jclouds.util.Strings2.toStringAndClose; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.math.BigInteger; import java.security.interfaces.DSAParams; import java.security.interfaces.DSAPublicKey; import java.security.spec.DSAPublicKeySpec; import com.google.common.base.Charsets; import com.google.common.base.Splitter; import com.google.common.hash.HashCode; import com.google.common.hash.Hashing; import com.google.common.io.ByteSource; import com.google.common.io.ByteStreams; /** * Utility methods to work with DSA SSH keys. * <p> * Methods in this class should be moved to the {@link org.jclouds.ssh.SshKeys} class. * * * @see org.jclouds.ssh.SshKeys */ public class DSAKeys { public static String encodeAsOpenSSH(DSAPublicKey key) { DSAParams params = key.getParams(); byte[] keyBlob = keyBlob(params.getP(), params.getQ(), params.getG(), key.getY()); return "ssh-dss " + base64().encode(keyBlob); } /** * Executes {@link org.jclouds.crypto.Pems#publicKeySpecFromOpenSSH(com.google.common.io.InputSupplier)} on the * string which was OpenSSH Base64 Encoded {@code id_rsa.pub} * * @param idRsaPub formatted {@code ssh-dss AAAAB3NzaC1yc2EAAAADAQABAAAB...} * @see org.jclouds.crypto.Pems#publicKeySpecFromOpenSSH(com.google.common.io.InputSupplier) */ public static DSAPublicKeySpec publicKeySpecFromOpenSSH(String idDsaPub) { try { return publicKeySpecFromOpenSSH(ByteSource.wrap(idDsaPub.getBytes(Charsets.UTF_8))); } catch (IOException e) { throw propagate(e); } } /** * Returns {@link java.security.spec.DSAPublicKeySpec} which was OpenSSH Base64 Encoded {@code id_rsa.pub} * * @param supplier the input stream factory, formatted {@code ssh-dss AAAAB3NzaC1yc2EAAAADAQABAAAB...} * * @return the {@link java.security.spec.DSAPublicKeySpec} which was OpenSSH Base64 Encoded {@code id_rsa.pub} * @throws java.io.IOException if an I/O error occurs */ public static DSAPublicKeySpec publicKeySpecFromOpenSSH(ByteSource supplier) throws IOException { InputStream stream = supplier.openStream(); Iterable<String> parts = Splitter.on(' ').split(toStringAndClose(stream).trim()); checkArgument(size(parts) >= 2 && "ssh-dss".equals(get(parts, 0)), "bad format, should be: ssh-dss AAAAB3..."); stream = new ByteArrayInputStream(base64().decode(get(parts, 1))); String marker = new String(readLengthFirst(stream)); checkArgument("ssh-dss".equals(marker), "looking for marker ssh-dss but got %s", marker); BigInteger p = new BigInteger(readLengthFirst(stream)); BigInteger q = new BigInteger(readLengthFirst(stream)); BigInteger g = new BigInteger(readLengthFirst(stream)); BigInteger y = new BigInteger(readLengthFirst(stream)); return new DSAPublicKeySpec(y, p, q, g); } /** * @param publicKeyOpenSSH RSA public key in OpenSSH format * @return fingerprint ex. {@code 2b:a9:62:95:5b:8b:1d:61:e0:92:f7:03:10:e9:db:d9} */ public static String fingerprintPublicKey(String publicKeyOpenSSH) { DSAPublicKeySpec publicKeySpec = publicKeySpecFromOpenSSH(publicKeyOpenSSH); return fingerprint(publicKeySpec.getP(), publicKeySpec.getQ(), publicKeySpec.getG(), publicKeySpec.getY()); } /** * Create a fingerprint per the following <a href="http://tools.ietf.org/html/draft-friedl-secsh-fingerprint-00" * >spec</a> * * @return hex fingerprint ex. {@code 2b:a9:62:95:5b:8b:1d:61:e0:92:f7:03:10:e9:db:d9} */ public static String fingerprint(BigInteger p, BigInteger q, BigInteger g, BigInteger y) { byte[] keyBlob = keyBlob(p, q, g, y); return hexColonDelimited(Hashing.md5().hashBytes(keyBlob)); } /** * @see org.jclouds.ssh.SshKeys */ private static String hexColonDelimited(HashCode hc) { return on(':').join(fixedLength(2).split(base16().lowerCase().encode(hc.asBytes()))); } /** * @see org.jclouds.ssh.SshKeys */ private static byte[] keyBlob(BigInteger p, BigInteger q, BigInteger g, BigInteger y) { try { ByteArrayOutputStream out = new ByteArrayOutputStream(); writeLengthFirst("ssh-dss".getBytes(), out); writeLengthFirst(p.toByteArray(), out); writeLengthFirst(q.toByteArray(), out); writeLengthFirst(g.toByteArray(), out); writeLengthFirst(y.toByteArray(), out); return out.toByteArray(); } catch (IOException e) { throw propagate(e); } } /** * @see org.jclouds.ssh.SshKeys */ // http://www.ietf.org/rfc/rfc4253.txt private static byte[] readLengthFirst(InputStream in) throws IOException { int byte1 = in.read(); int byte2 = in.read(); int byte3 = in.read(); int byte4 = in.read(); int length = (byte1 << 24) + (byte2 << 16) + (byte3 << 8) + (byte4 << 0); byte[] val = new byte[length]; ByteStreams.readFully(in, val); return val; } /** * @see org.jclouds.ssh.SshKeys */ // http://www.ietf.org/rfc/rfc4253.txt private static void writeLengthFirst(byte[] array, ByteArrayOutputStream out) throws IOException { out.write(array.length >>> 24 & 0xFF); out.write(array.length >>> 16 & 0xFF); out.write(array.length >>> 8 & 0xFF); out.write(array.length >>> 0 & 0xFF); if (array.length == 1 && array[0] == (byte) 0x00) { out.write(new byte[0]); } else { out.write(array); } } }