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/**
* Copyright (c) 2011, 2018 Gunnar Wagenknecht and others.
* All rights reserved.
*
* This program and the accompanying materials are made available under the terms of the
* Eclipse Public License v1.0 which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Gunnar Wagenknecht - initial API and implementation
*/
package org.eclipse.equinox.console.internal.ssh;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PublicKey;
import java.security.spec.DSAPublicKeySpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPublicKeySpec;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
import org.apache.mina.util.Base64;
/**
* Reader for 'authorized_keys' file as typically found on Unix systems.
*/
public class AuthorizedKeys {
public static enum KeyType {
RSA, DSA
}
public static class ParseKeyException extends IOException {
/** serialVersionUID */
private static final long serialVersionUID = 1L;
/**
* Creates a new instance.
*
* @param message
* @param cause
*/
public ParseKeyException(final String message, final Throwable cause) {
super(message, cause);
}
}
private static final String PREFIX_KEY_TYPE = "ssh-";
private static final String PREFIX_KEY_TYPE_DSA = "ssh-dsa ";
private static final String PREFIX_KEY_TYPE_RSA = "ssh-rsa ";
private static final String NEWLINE = "\n";
private static byte[] asBytes(final String string) {
return string.getBytes(StandardCharsets.UTF_8);
}
private static String asString(final byte[] bytes) {
return new String(bytes, StandardCharsets.UTF_8);
}
public static void main(final String[] args) {
try {
final List<PublicKey> keys = new AuthorizedKeys(args[0]).getKeys();
for (final PublicKey key : keys) {
System.out.println(key);
}
} catch (final Exception e) {
e.printStackTrace();
}
}
private final List<PublicKey> keys;
/**
* Creates a new instance.
*
* @throws FileNotFoundException
*/
public AuthorizedKeys(final String authorizedKeysFile) throws FileNotFoundException, IOException {
// read file line-by-line
final File file = new File(authorizedKeysFile);
try (Scanner scanner = new Scanner(file)) {
scanner.useDelimiter(NEWLINE);
int lineNumber = 0;
final List<PublicKey> keys = new ArrayList<>();
while (scanner.hasNext()) {
lineNumber++;
// get line (without leading and trailing blanks)
final String line = scanner.next().trim();
// ignore blank line and comments
if ((line.length() == 0) || (line.charAt(0) == '#')) {
continue;
}
// read key
try {
keys.add(readPublicKey(line));
} catch (final Exception e) {
throw new ParseKeyException("Line " + lineNumber + ": " + e.getMessage(), e);
}
}
this.keys = Collections.unmodifiableList(keys);
}
}
/**
* Returns the keys.
*
* @return the keys
*/
public List<PublicKey> getKeys() {
return keys;
}
private BigInteger readBigInteger(final ByteBuffer buffer) {
final int len = buffer.getInt();
final byte[] bytes = new byte[len];
buffer.get(bytes);
final BigInteger pubExp = new BigInteger(bytes);
return pubExp;
}
private PublicKey readPublicKey(String line) throws IOException, InvalidKeySpecException, NoSuchAlgorithmException {
// [options] <type> <base64> <comment>
final KeyType type;
final byte[] key;
// skip options (if any)
if (!line.startsWith(PREFIX_KEY_TYPE)) {
final int keyTypeStart = line.indexOf(PREFIX_KEY_TYPE);
if (keyTypeStart == -1) {
throw new IOException("missing key type");
}
line = line.substring(keyTypeStart);
}
// key type
if (line.startsWith(PREFIX_KEY_TYPE_DSA)) {
line = line.substring(PREFIX_KEY_TYPE_DSA.length());
type = KeyType.DSA;
} else if (line.startsWith(PREFIX_KEY_TYPE_RSA)) {
line = line.substring(PREFIX_KEY_TYPE_RSA.length());
type = KeyType.RSA;
} else {
throw new IOException("unsupported key type");
}
// key
final int keyEndIdx = line.indexOf(' ');
if (keyEndIdx != -1) {
key = Base64.decodeBase64(asBytes(line.substring(0, keyEndIdx)));
line = line.substring(keyEndIdx + 1);
} else {
key = Base64.decodeBase64(asBytes(line));
}
// wrap key into byte buffer
final ByteBuffer buffer = ByteBuffer.wrap(key);
// skip key type
readString(buffer);
// parse key
switch (type) {
case RSA:
// exponent + modulus
final BigInteger pubExp = readBigInteger(buffer);
final BigInteger mod = readBigInteger(buffer);
return KeyFactory.getInstance(KeyType.RSA.name()).generatePublic(new RSAPublicKeySpec(mod, pubExp));
case DSA:
// p + q+ g + y
final BigInteger p = readBigInteger(buffer);
final BigInteger q = readBigInteger(buffer);
final BigInteger g = readBigInteger(buffer);
final BigInteger y = readBigInteger(buffer);
return KeyFactory.getInstance(KeyType.DSA.name()).generatePublic(new DSAPublicKeySpec(y, p, q, g));
default:
throw new IOException("not implemented: " + type);
}
}
private String readString(final ByteBuffer buffer) {
final int len = buffer.getInt();
final byte[] bytes = new byte[len];
buffer.get(bytes);
return asString(bytes);
}
}
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