/**
|
* Functions to output keys in SSH-friendly formats.
|
*
|
* This is part of the Forge project which may be used under the terms of
|
* either the BSD License or the GNU General Public License (GPL) Version 2.
|
*
|
* See: https://github.com/digitalbazaar/forge/blob/cbebca3780658703d925b61b2caffb1d263a6c1d/LICENSE
|
*
|
* @author https://github.com/shellac
|
*/
|
var forge = require('./forge');
|
require('./aes');
|
require('./hmac');
|
require('./md5');
|
require('./sha1');
|
require('./util');
|
|
var ssh = module.exports = forge.ssh = forge.ssh || {};
|
|
/**
|
* Encodes (and optionally encrypts) a private RSA key as a Putty PPK file.
|
*
|
* @param privateKey the key.
|
* @param passphrase a passphrase to protect the key (falsy for no encryption).
|
* @param comment a comment to include in the key file.
|
*
|
* @return the PPK file as a string.
|
*/
|
ssh.privateKeyToPutty = function(privateKey, passphrase, comment) {
|
comment = comment || '';
|
passphrase = passphrase || '';
|
var algorithm = 'ssh-rsa';
|
var encryptionAlgorithm = (passphrase === '') ? 'none' : 'aes256-cbc';
|
|
var ppk = 'PuTTY-User-Key-File-2: ' + algorithm + '\r\n';
|
ppk += 'Encryption: ' + encryptionAlgorithm + '\r\n';
|
ppk += 'Comment: ' + comment + '\r\n';
|
|
// public key into buffer for ppk
|
var pubbuffer = forge.util.createBuffer();
|
_addStringToBuffer(pubbuffer, algorithm);
|
_addBigIntegerToBuffer(pubbuffer, privateKey.e);
|
_addBigIntegerToBuffer(pubbuffer, privateKey.n);
|
|
// write public key
|
var pub = forge.util.encode64(pubbuffer.bytes(), 64);
|
var length = Math.floor(pub.length / 66) + 1; // 66 = 64 + \r\n
|
ppk += 'Public-Lines: ' + length + '\r\n';
|
ppk += pub;
|
|
// private key into a buffer
|
var privbuffer = forge.util.createBuffer();
|
_addBigIntegerToBuffer(privbuffer, privateKey.d);
|
_addBigIntegerToBuffer(privbuffer, privateKey.p);
|
_addBigIntegerToBuffer(privbuffer, privateKey.q);
|
_addBigIntegerToBuffer(privbuffer, privateKey.qInv);
|
|
// optionally encrypt the private key
|
var priv;
|
if(!passphrase) {
|
// use the unencrypted buffer
|
priv = forge.util.encode64(privbuffer.bytes(), 64);
|
} else {
|
// encrypt RSA key using passphrase
|
var encLen = privbuffer.length() + 16 - 1;
|
encLen -= encLen % 16;
|
|
// pad private key with sha1-d data -- needs to be a multiple of 16
|
var padding = _sha1(privbuffer.bytes());
|
|
padding.truncate(padding.length() - encLen + privbuffer.length());
|
privbuffer.putBuffer(padding);
|
|
var aeskey = forge.util.createBuffer();
|
aeskey.putBuffer(_sha1('\x00\x00\x00\x00', passphrase));
|
aeskey.putBuffer(_sha1('\x00\x00\x00\x01', passphrase));
|
|
// encrypt some bytes using CBC mode
|
// key is 40 bytes, so truncate *by* 8 bytes
|
var cipher = forge.aes.createEncryptionCipher(aeskey.truncate(8), 'CBC');
|
cipher.start(forge.util.createBuffer().fillWithByte(0, 16));
|
cipher.update(privbuffer.copy());
|
cipher.finish();
|
var encrypted = cipher.output;
|
|
// Note: this appears to differ from Putty -- is forge wrong, or putty?
|
// due to padding we finish as an exact multiple of 16
|
encrypted.truncate(16); // all padding
|
|
priv = forge.util.encode64(encrypted.bytes(), 64);
|
}
|
|
// output private key
|
length = Math.floor(priv.length / 66) + 1; // 64 + \r\n
|
ppk += '\r\nPrivate-Lines: ' + length + '\r\n';
|
ppk += priv;
|
|
// MAC
|
var mackey = _sha1('putty-private-key-file-mac-key', passphrase);
|
|
var macbuffer = forge.util.createBuffer();
|
_addStringToBuffer(macbuffer, algorithm);
|
_addStringToBuffer(macbuffer, encryptionAlgorithm);
|
_addStringToBuffer(macbuffer, comment);
|
macbuffer.putInt32(pubbuffer.length());
|
macbuffer.putBuffer(pubbuffer);
|
macbuffer.putInt32(privbuffer.length());
|
macbuffer.putBuffer(privbuffer);
|
|
var hmac = forge.hmac.create();
|
hmac.start('sha1', mackey);
|
hmac.update(macbuffer.bytes());
|
|
ppk += '\r\nPrivate-MAC: ' + hmac.digest().toHex() + '\r\n';
|
|
return ppk;
|
};
|
|
/**
|
* Encodes a public RSA key as an OpenSSH file.
|
*
|
* @param key the key.
|
* @param comment a comment.
|
*
|
* @return the public key in OpenSSH format.
|
*/
|
ssh.publicKeyToOpenSSH = function(key, comment) {
|
var type = 'ssh-rsa';
|
comment = comment || '';
|
|
var buffer = forge.util.createBuffer();
|
_addStringToBuffer(buffer, type);
|
_addBigIntegerToBuffer(buffer, key.e);
|
_addBigIntegerToBuffer(buffer, key.n);
|
|
return type + ' ' + forge.util.encode64(buffer.bytes()) + ' ' + comment;
|
};
|
|
/**
|
* Encodes a private RSA key as an OpenSSH file.
|
*
|
* @param key the key.
|
* @param passphrase a passphrase to protect the key (falsy for no encryption).
|
*
|
* @return the public key in OpenSSH format.
|
*/
|
ssh.privateKeyToOpenSSH = function(privateKey, passphrase) {
|
if(!passphrase) {
|
return forge.pki.privateKeyToPem(privateKey);
|
}
|
// OpenSSH private key is just a legacy format, it seems
|
return forge.pki.encryptRsaPrivateKey(privateKey, passphrase,
|
{legacy: true, algorithm: 'aes128'});
|
};
|
|
/**
|
* Gets the SSH fingerprint for the given public key.
|
*
|
* @param options the options to use.
|
* [md] the message digest object to use (defaults to forge.md.md5).
|
* [encoding] an alternative output encoding, such as 'hex'
|
* (defaults to none, outputs a byte buffer).
|
* [delimiter] the delimiter to use between bytes for 'hex' encoded
|
* output, eg: ':' (defaults to none).
|
*
|
* @return the fingerprint as a byte buffer or other encoding based on options.
|
*/
|
ssh.getPublicKeyFingerprint = function(key, options) {
|
options = options || {};
|
var md = options.md || forge.md.md5.create();
|
|
var type = 'ssh-rsa';
|
var buffer = forge.util.createBuffer();
|
_addStringToBuffer(buffer, type);
|
_addBigIntegerToBuffer(buffer, key.e);
|
_addBigIntegerToBuffer(buffer, key.n);
|
|
// hash public key bytes
|
md.start();
|
md.update(buffer.getBytes());
|
var digest = md.digest();
|
if(options.encoding === 'hex') {
|
var hex = digest.toHex();
|
if(options.delimiter) {
|
return hex.match(/.{2}/g).join(options.delimiter);
|
}
|
return hex;
|
} else if(options.encoding === 'binary') {
|
return digest.getBytes();
|
} else if(options.encoding) {
|
throw new Error('Unknown encoding "' + options.encoding + '".');
|
}
|
return digest;
|
};
|
|
/**
|
* Adds len(val) then val to a buffer.
|
*
|
* @param buffer the buffer to add to.
|
* @param val a big integer.
|
*/
|
function _addBigIntegerToBuffer(buffer, val) {
|
var hexVal = val.toString(16);
|
// ensure 2s complement +ve
|
if(hexVal[0] >= '8') {
|
hexVal = '00' + hexVal;
|
}
|
var bytes = forge.util.hexToBytes(hexVal);
|
buffer.putInt32(bytes.length);
|
buffer.putBytes(bytes);
|
}
|
|
/**
|
* Adds len(val) then val to a buffer.
|
*
|
* @param buffer the buffer to add to.
|
* @param val a string.
|
*/
|
function _addStringToBuffer(buffer, val) {
|
buffer.putInt32(val.length);
|
buffer.putString(val);
|
}
|
|
/**
|
* Hashes the arguments into one value using SHA-1.
|
*
|
* @return the sha1 hash of the provided arguments.
|
*/
|
function _sha1() {
|
var sha = forge.md.sha1.create();
|
var num = arguments.length;
|
for (var i = 0; i < num; ++i) {
|
sha.update(arguments[i]);
|
}
|
return sha.digest();
|
}
|
