1 | // Copyright 2015 Joyent, Inc.
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2 |
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3 | module.exports = {
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4 | read: read,
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5 | readSSHPrivate: readSSHPrivate,
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6 | write: write
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7 | };
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8 |
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9 | var assert = require('assert-plus');
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10 | var asn1 = require('asn1');
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11 | var Buffer = require('safer-buffer').Buffer;
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12 | var algs = require('../algs');
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13 | var utils = require('../utils');
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14 | var crypto = require('crypto');
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15 |
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16 | var Key = require('../key');
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17 | var PrivateKey = require('../private-key');
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18 | var pem = require('./pem');
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19 | var rfc4253 = require('./rfc4253');
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20 | var SSHBuffer = require('../ssh-buffer');
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21 | var errors = require('../errors');
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22 |
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23 | var bcrypt;
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24 |
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25 | function read(buf, options) {
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26 | return (pem.read(buf, options));
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27 | }
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28 |
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29 | var MAGIC = 'openssh-key-v1';
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30 |
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31 | function readSSHPrivate(type, buf, options) {
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32 | buf = new SSHBuffer({buffer: buf});
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33 |
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34 | var magic = buf.readCString();
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35 | assert.strictEqual(magic, MAGIC, 'bad magic string');
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36 |
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37 | var cipher = buf.readString();
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38 | var kdf = buf.readString();
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39 | var kdfOpts = buf.readBuffer();
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40 |
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41 | var nkeys = buf.readInt();
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42 | if (nkeys !== 1) {
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43 | throw (new Error('OpenSSH-format key file contains ' +
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44 | 'multiple keys: this is unsupported.'));
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45 | }
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46 |
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47 | var pubKey = buf.readBuffer();
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48 |
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49 | if (type === 'public') {
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50 | assert.ok(buf.atEnd(), 'excess bytes left after key');
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51 | return (rfc4253.read(pubKey));
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52 | }
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53 |
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54 | var privKeyBlob = buf.readBuffer();
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55 | assert.ok(buf.atEnd(), 'excess bytes left after key');
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56 |
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57 | var kdfOptsBuf = new SSHBuffer({ buffer: kdfOpts });
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58 | switch (kdf) {
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59 | case 'none':
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60 | if (cipher !== 'none') {
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61 | throw (new Error('OpenSSH-format key uses KDF "none" ' +
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62 | 'but specifies a cipher other than "none"'));
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63 | }
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64 | break;
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65 | case 'bcrypt':
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66 | var salt = kdfOptsBuf.readBuffer();
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67 | var rounds = kdfOptsBuf.readInt();
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68 | var cinf = utils.opensshCipherInfo(cipher);
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69 | if (bcrypt === undefined) {
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70 | bcrypt = require('bcrypt-pbkdf');
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71 | }
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72 |
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73 | if (typeof (options.passphrase) === 'string') {
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74 | options.passphrase = Buffer.from(options.passphrase,
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75 | 'utf-8');
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76 | }
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77 | if (!Buffer.isBuffer(options.passphrase)) {
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78 | throw (new errors.KeyEncryptedError(
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79 | options.filename, 'OpenSSH'));
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80 | }
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81 |
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82 | var pass = new Uint8Array(options.passphrase);
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83 | var salti = new Uint8Array(salt);
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84 | /* Use the pbkdf to derive both the key and the IV. */
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85 | var out = new Uint8Array(cinf.keySize + cinf.blockSize);
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86 | var res = bcrypt.pbkdf(pass, pass.length, salti, salti.length,
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87 | out, out.length, rounds);
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88 | if (res !== 0) {
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89 | throw (new Error('bcrypt_pbkdf function returned ' +
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90 | 'failure, parameters invalid'));
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91 | }
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92 | out = Buffer.from(out);
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93 | var ckey = out.slice(0, cinf.keySize);
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94 | var iv = out.slice(cinf.keySize, cinf.keySize + cinf.blockSize);
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95 | var cipherStream = crypto.createDecipheriv(cinf.opensslName,
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96 | ckey, iv);
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97 | cipherStream.setAutoPadding(false);
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98 | var chunk, chunks = [];
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99 | cipherStream.once('error', function (e) {
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100 | if (e.toString().indexOf('bad decrypt') !== -1) {
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101 | throw (new Error('Incorrect passphrase ' +
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102 | 'supplied, could not decrypt key'));
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103 | }
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104 | throw (e);
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105 | });
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106 | cipherStream.write(privKeyBlob);
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107 | cipherStream.end();
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108 | while ((chunk = cipherStream.read()) !== null)
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109 | chunks.push(chunk);
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110 | privKeyBlob = Buffer.concat(chunks);
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111 | break;
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112 | default:
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113 | throw (new Error(
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114 | 'OpenSSH-format key uses unknown KDF "' + kdf + '"'));
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115 | }
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116 |
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117 | buf = new SSHBuffer({buffer: privKeyBlob});
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118 |
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119 | var checkInt1 = buf.readInt();
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120 | var checkInt2 = buf.readInt();
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121 | if (checkInt1 !== checkInt2) {
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122 | throw (new Error('Incorrect passphrase supplied, could not ' +
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123 | 'decrypt key'));
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124 | }
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125 |
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126 | var ret = {};
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127 | var key = rfc4253.readInternal(ret, 'private', buf.remainder());
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128 |
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129 | buf.skip(ret.consumed);
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130 |
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131 | var comment = buf.readString();
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132 | key.comment = comment;
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133 |
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134 | return (key);
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135 | }
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136 |
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137 | function write(key, options) {
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138 | var pubKey;
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139 | if (PrivateKey.isPrivateKey(key))
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140 | pubKey = key.toPublic();
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141 | else
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142 | pubKey = key;
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143 |
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144 | var cipher = 'none';
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145 | var kdf = 'none';
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146 | var kdfopts = Buffer.alloc(0);
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147 | var cinf = { blockSize: 8 };
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148 | var passphrase;
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149 | if (options !== undefined) {
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150 | passphrase = options.passphrase;
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151 | if (typeof (passphrase) === 'string')
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152 | passphrase = Buffer.from(passphrase, 'utf-8');
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153 | if (passphrase !== undefined) {
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154 | assert.buffer(passphrase, 'options.passphrase');
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155 | assert.optionalString(options.cipher, 'options.cipher');
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156 | cipher = options.cipher;
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157 | if (cipher === undefined)
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158 | cipher = 'aes128-ctr';
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159 | cinf = utils.opensshCipherInfo(cipher);
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160 | kdf = 'bcrypt';
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161 | }
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162 | }
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163 |
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164 | var privBuf;
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165 | if (PrivateKey.isPrivateKey(key)) {
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166 | privBuf = new SSHBuffer({});
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167 | var checkInt = crypto.randomBytes(4).readUInt32BE(0);
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168 | privBuf.writeInt(checkInt);
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169 | privBuf.writeInt(checkInt);
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170 | privBuf.write(key.toBuffer('rfc4253'));
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171 | privBuf.writeString(key.comment || '');
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172 |
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173 | var n = 1;
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174 | while (privBuf._offset % cinf.blockSize !== 0)
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175 | privBuf.writeChar(n++);
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176 | privBuf = privBuf.toBuffer();
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177 | }
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178 |
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179 | switch (kdf) {
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180 | case 'none':
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181 | break;
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182 | case 'bcrypt':
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183 | var salt = crypto.randomBytes(16);
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184 | var rounds = 16;
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185 | var kdfssh = new SSHBuffer({});
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186 | kdfssh.writeBuffer(salt);
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187 | kdfssh.writeInt(rounds);
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188 | kdfopts = kdfssh.toBuffer();
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189 |
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190 | if (bcrypt === undefined) {
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191 | bcrypt = require('bcrypt-pbkdf');
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192 | }
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193 | var pass = new Uint8Array(passphrase);
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194 | var salti = new Uint8Array(salt);
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195 | /* Use the pbkdf to derive both the key and the IV. */
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196 | var out = new Uint8Array(cinf.keySize + cinf.blockSize);
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197 | var res = bcrypt.pbkdf(pass, pass.length, salti, salti.length,
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198 | out, out.length, rounds);
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199 | if (res !== 0) {
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200 | throw (new Error('bcrypt_pbkdf function returned ' +
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201 | 'failure, parameters invalid'));
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202 | }
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203 | out = Buffer.from(out);
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204 | var ckey = out.slice(0, cinf.keySize);
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205 | var iv = out.slice(cinf.keySize, cinf.keySize + cinf.blockSize);
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206 |
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207 | var cipherStream = crypto.createCipheriv(cinf.opensslName,
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208 | ckey, iv);
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209 | cipherStream.setAutoPadding(false);
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210 | var chunk, chunks = [];
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211 | cipherStream.once('error', function (e) {
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212 | throw (e);
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213 | });
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214 | cipherStream.write(privBuf);
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215 | cipherStream.end();
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216 | while ((chunk = cipherStream.read()) !== null)
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217 | chunks.push(chunk);
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218 | privBuf = Buffer.concat(chunks);
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219 | break;
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220 | default:
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221 | throw (new Error('Unsupported kdf ' + kdf));
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222 | }
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223 |
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224 | var buf = new SSHBuffer({});
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225 |
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226 | buf.writeCString(MAGIC);
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227 | buf.writeString(cipher); /* cipher */
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228 | buf.writeString(kdf); /* kdf */
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229 | buf.writeBuffer(kdfopts); /* kdfoptions */
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230 |
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231 | buf.writeInt(1); /* nkeys */
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232 | buf.writeBuffer(pubKey.toBuffer('rfc4253'));
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233 |
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234 | if (privBuf)
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235 | buf.writeBuffer(privBuf);
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236 |
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237 | buf = buf.toBuffer();
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238 |
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239 | var header;
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240 | if (PrivateKey.isPrivateKey(key))
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241 | header = 'OPENSSH PRIVATE KEY';
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242 | else
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243 | header = 'OPENSSH PUBLIC KEY';
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244 |
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245 | var tmp = buf.toString('base64');
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246 | var len = tmp.length + (tmp.length / 70) +
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247 | 18 + 16 + header.length*2 + 10;
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248 | buf = Buffer.alloc(len);
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249 | var o = 0;
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250 | o += buf.write('-----BEGIN ' + header + '-----\n', o);
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251 | for (var i = 0; i < tmp.length; ) {
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252 | var limit = i + 70;
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253 | if (limit > tmp.length)
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254 | limit = tmp.length;
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255 | o += buf.write(tmp.slice(i, limit), o);
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256 | buf[o++] = 10;
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257 | i = limit;
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258 | }
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259 | o += buf.write('-----END ' + header + '-----\n', o);
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260 |
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261 | return (buf.slice(0, o));
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262 | }
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