keygen.js•18.3 kB
'use strict';
const {
createCipheriv,
generateKeyPair: generateKeyPair_,
generateKeyPairSync: generateKeyPairSync_,
getCurves,
randomBytes,
} = require('crypto');
const { Ber } = require('asn1');
const bcrypt_pbkdf = require('bcrypt-pbkdf').pbkdf;
const { CIPHER_INFO } = require('./protocol/crypto.js');
const SALT_LEN = 16;
const DEFAULT_ROUNDS = 16;
const curves = getCurves();
const ciphers = new Map(Object.entries(CIPHER_INFO));
function makeArgs(type, opts) {
if (typeof type !== 'string')
throw new TypeError('Key type must be a string');
const publicKeyEncoding = { type: 'spki', format: 'der' };
const privateKeyEncoding = { type: 'pkcs8', format: 'der' };
switch (type.toLowerCase()) {
case 'rsa': {
if (typeof opts !== 'object' || opts === null)
throw new TypeError('Missing options object for RSA key');
const modulusLength = opts.bits;
if (!Number.isInteger(modulusLength))
throw new TypeError('RSA bits must be an integer');
if (modulusLength <= 0 || modulusLength > 16384)
throw new RangeError('RSA bits must be non-zero and <= 16384');
return ['rsa', { modulusLength, publicKeyEncoding, privateKeyEncoding }];
}
case 'ecdsa': {
if (typeof opts !== 'object' || opts === null)
throw new TypeError('Missing options object for ECDSA key');
if (!Number.isInteger(opts.bits))
throw new TypeError('ECDSA bits must be an integer');
let namedCurve;
switch (opts.bits) {
case 256:
namedCurve = 'prime256v1';
break;
case 384:
namedCurve = 'secp384r1';
break;
case 521:
namedCurve = 'secp521r1';
break;
default:
throw new Error('ECDSA bits must be 256, 384, or 521');
}
if (!curves.includes(namedCurve))
throw new Error('Unsupported ECDSA bits value');
return ['ec', { namedCurve, publicKeyEncoding, privateKeyEncoding }];
}
case 'ed25519':
return ['ed25519', { publicKeyEncoding, privateKeyEncoding }];
default:
throw new Error(`Unsupported key type: ${type}`);
}
}
function parseDERs(keyType, pub, priv) {
switch (keyType) {
case 'rsa': {
// Note: we don't need to parse the public key since the PKCS8 private key
// already includes the public key parameters
// Parse private key
let reader = new Ber.Reader(priv);
reader.readSequence();
// - Version
if (reader.readInt() !== 0)
throw new Error('Unsupported version in RSA private key');
// - Algorithm
reader.readSequence();
if (reader.readOID() !== '1.2.840.113549.1.1.1')
throw new Error('Bad RSA private OID');
// - Algorithm parameters (RSA has none)
if (reader.readByte() !== Ber.Null)
throw new Error('Malformed RSA private key (expected null)');
if (reader.readByte() !== 0x00) {
throw new Error(
'Malformed RSA private key (expected zero-length null)'
);
}
reader = new Ber.Reader(reader.readString(Ber.OctetString, true));
reader.readSequence();
if (reader.readInt() !== 0)
throw new Error('Unsupported version in RSA private key');
const n = reader.readString(Ber.Integer, true);
const e = reader.readString(Ber.Integer, true);
const d = reader.readString(Ber.Integer, true);
const p = reader.readString(Ber.Integer, true);
const q = reader.readString(Ber.Integer, true);
reader.readString(Ber.Integer, true); // dmp1
reader.readString(Ber.Integer, true); // dmq1
const iqmp = reader.readString(Ber.Integer, true);
/*
OpenSSH RSA private key:
string "ssh-rsa"
string n -- public
string e -- public
string d -- private
string iqmp -- private
string p -- private
string q -- private
*/
const keyName = Buffer.from('ssh-rsa');
const privBuf = Buffer.allocUnsafe(
4 + keyName.length
+ 4 + n.length
+ 4 + e.length
+ 4 + d.length
+ 4 + iqmp.length
+ 4 + p.length
+ 4 + q.length
);
let pos = 0;
privBuf.writeUInt32BE(keyName.length, pos += 0);
privBuf.set(keyName, pos += 4);
privBuf.writeUInt32BE(n.length, pos += keyName.length);
privBuf.set(n, pos += 4);
privBuf.writeUInt32BE(e.length, pos += n.length);
privBuf.set(e, pos += 4);
privBuf.writeUInt32BE(d.length, pos += e.length);
privBuf.set(d, pos += 4);
privBuf.writeUInt32BE(iqmp.length, pos += d.length);
privBuf.set(iqmp, pos += 4);
privBuf.writeUInt32BE(p.length, pos += iqmp.length);
privBuf.set(p, pos += 4);
privBuf.writeUInt32BE(q.length, pos += p.length);
privBuf.set(q, pos += 4);
/*
OpenSSH RSA public key:
string "ssh-rsa"
string e -- public
string n -- public
*/
const pubBuf = Buffer.allocUnsafe(
4 + keyName.length
+ 4 + e.length
+ 4 + n.length
);
pos = 0;
pubBuf.writeUInt32BE(keyName.length, pos += 0);
pubBuf.set(keyName, pos += 4);
pubBuf.writeUInt32BE(e.length, pos += keyName.length);
pubBuf.set(e, pos += 4);
pubBuf.writeUInt32BE(n.length, pos += e.length);
pubBuf.set(n, pos += 4);
return { sshName: keyName.toString(), priv: privBuf, pub: pubBuf };
}
case 'ec': {
// Parse public key
let reader = new Ber.Reader(pub);
reader.readSequence();
reader.readSequence();
if (reader.readOID() !== '1.2.840.10045.2.1')
throw new Error('Bad ECDSA public OID');
// Skip curve OID, we'll get it from the private key
reader.readOID();
let pubBin = reader.readString(Ber.BitString, true);
{
// Remove leading zero bytes
let i = 0;
for (; i < pubBin.length && pubBin[i] === 0x00; ++i);
if (i > 0)
pubBin = pubBin.slice(i);
}
// Parse private key
reader = new Ber.Reader(priv);
reader.readSequence();
// - Version
if (reader.readInt() !== 0)
throw new Error('Unsupported version in ECDSA private key');
reader.readSequence();
if (reader.readOID() !== '1.2.840.10045.2.1')
throw new Error('Bad ECDSA private OID');
const curveOID = reader.readOID();
let sshCurveName;
switch (curveOID) {
case '1.2.840.10045.3.1.7':
// prime256v1/secp256r1
sshCurveName = 'nistp256';
break;
case '1.3.132.0.34':
// secp384r1
sshCurveName = 'nistp384';
break;
case '1.3.132.0.35':
// secp521r1
sshCurveName = 'nistp521';
break;
default:
throw new Error('Unsupported curve in ECDSA private key');
}
reader = new Ber.Reader(reader.readString(Ber.OctetString, true));
reader.readSequence();
// - Version
if (reader.readInt() !== 1)
throw new Error('Unsupported version in ECDSA private key');
// Add leading zero byte to prevent negative bignum in private key
const privBin = Buffer.concat([
Buffer.from([0x00]),
reader.readString(Ber.OctetString, true)
]);
/*
OpenSSH ECDSA private key:
string "ecdsa-sha2-<sshCurveName>"
string curve name
string Q -- public
string d -- private
*/
const keyName = Buffer.from(`ecdsa-sha2-${sshCurveName}`);
sshCurveName = Buffer.from(sshCurveName);
const privBuf = Buffer.allocUnsafe(
4 + keyName.length
+ 4 + sshCurveName.length
+ 4 + pubBin.length
+ 4 + privBin.length
);
let pos = 0;
privBuf.writeUInt32BE(keyName.length, pos += 0);
privBuf.set(keyName, pos += 4);
privBuf.writeUInt32BE(sshCurveName.length, pos += keyName.length);
privBuf.set(sshCurveName, pos += 4);
privBuf.writeUInt32BE(pubBin.length, pos += sshCurveName.length);
privBuf.set(pubBin, pos += 4);
privBuf.writeUInt32BE(privBin.length, pos += pubBin.length);
privBuf.set(privBin, pos += 4);
/*
OpenSSH ECDSA public key:
string "ecdsa-sha2-<sshCurveName>"
string curve name
string Q -- public
*/
const pubBuf = Buffer.allocUnsafe(
4 + keyName.length
+ 4 + sshCurveName.length
+ 4 + pubBin.length
);
pos = 0;
pubBuf.writeUInt32BE(keyName.length, pos += 0);
pubBuf.set(keyName, pos += 4);
pubBuf.writeUInt32BE(sshCurveName.length, pos += keyName.length);
pubBuf.set(sshCurveName, pos += 4);
pubBuf.writeUInt32BE(pubBin.length, pos += sshCurveName.length);
pubBuf.set(pubBin, pos += 4);
return { sshName: keyName.toString(), priv: privBuf, pub: pubBuf };
}
case 'ed25519': {
// Parse public key
let reader = new Ber.Reader(pub);
reader.readSequence();
// - Algorithm
reader.readSequence();
if (reader.readOID() !== '1.3.101.112')
throw new Error('Bad ED25519 public OID');
// - Attributes (absent for ED25519)
let pubBin = reader.readString(Ber.BitString, true);
{
// Remove leading zero bytes
let i = 0;
for (; i < pubBin.length && pubBin[i] === 0x00; ++i);
if (i > 0)
pubBin = pubBin.slice(i);
}
// Parse private key
reader = new Ber.Reader(priv);
reader.readSequence();
// - Version
if (reader.readInt() !== 0)
throw new Error('Unsupported version in ED25519 private key');
// - Algorithm
reader.readSequence();
if (reader.readOID() !== '1.3.101.112')
throw new Error('Bad ED25519 private OID');
// - Attributes (absent)
reader = new Ber.Reader(reader.readString(Ber.OctetString, true));
const privBin = reader.readString(Ber.OctetString, true);
/*
OpenSSH ed25519 private key:
string "ssh-ed25519"
string public key
string private key + public key
*/
const keyName = Buffer.from('ssh-ed25519');
const privBuf = Buffer.allocUnsafe(
4 + keyName.length
+ 4 + pubBin.length
+ 4 + (privBin.length + pubBin.length)
);
let pos = 0;
privBuf.writeUInt32BE(keyName.length, pos += 0);
privBuf.set(keyName, pos += 4);
privBuf.writeUInt32BE(pubBin.length, pos += keyName.length);
privBuf.set(pubBin, pos += 4);
privBuf.writeUInt32BE(
privBin.length + pubBin.length,
pos += pubBin.length
);
privBuf.set(privBin, pos += 4);
privBuf.set(pubBin, pos += privBin.length);
/*
OpenSSH ed25519 public key:
string "ssh-ed25519"
string public key
*/
const pubBuf = Buffer.allocUnsafe(
4 + keyName.length
+ 4 + pubBin.length
);
pos = 0;
pubBuf.writeUInt32BE(keyName.length, pos += 0);
pubBuf.set(keyName, pos += 4);
pubBuf.writeUInt32BE(pubBin.length, pos += keyName.length);
pubBuf.set(pubBin, pos += 4);
return { sshName: keyName.toString(), priv: privBuf, pub: pubBuf };
}
}
}
function convertKeys(keyType, pub, priv, opts) {
let format = 'new';
let encrypted;
let comment = '';
if (typeof opts === 'object' && opts !== null) {
if (typeof opts.comment === 'string' && opts.comment)
comment = opts.comment;
if (typeof opts.format === 'string' && opts.format)
format = opts.format;
if (opts.passphrase) {
let passphrase;
if (typeof opts.passphrase === 'string')
passphrase = Buffer.from(opts.passphrase);
else if (Buffer.isBuffer(opts.passphrase))
passphrase = opts.passphrase;
else
throw new Error('Invalid passphrase');
if (opts.cipher === undefined)
throw new Error('Missing cipher name');
const cipher = ciphers.get(opts.cipher);
if (cipher === undefined)
throw new Error('Invalid cipher name');
if (format === 'new') {
let rounds = DEFAULT_ROUNDS;
if (opts.rounds !== undefined) {
if (!Number.isInteger(opts.rounds))
throw new TypeError('rounds must be an integer');
if (opts.rounds > 0)
rounds = opts.rounds;
}
const gen = Buffer.allocUnsafe(cipher.keyLen + cipher.ivLen);
const salt = randomBytes(SALT_LEN);
const r = bcrypt_pbkdf(
passphrase,
passphrase.length,
salt,
salt.length,
gen,
gen.length,
rounds
);
if (r !== 0)
return new Error('Failed to generate information to encrypt key');
/*
string salt
uint32 rounds
*/
const kdfOptions = Buffer.allocUnsafe(4 + salt.length + 4);
{
let pos = 0;
kdfOptions.writeUInt32BE(salt.length, pos += 0);
kdfOptions.set(salt, pos += 4);
kdfOptions.writeUInt32BE(rounds, pos += salt.length);
}
encrypted = {
cipher,
cipherName: opts.cipher,
kdfName: 'bcrypt',
kdfOptions,
key: gen.slice(0, cipher.keyLen),
iv: gen.slice(cipher.keyLen),
};
}
}
}
switch (format) {
case 'new': {
let privateB64 = '-----BEGIN OPENSSH PRIVATE KEY-----\n';
let publicB64;
/*
byte[] "openssh-key-v1\0"
string ciphername
string kdfname
string kdfoptions
uint32 number of keys N
string publickey1
string encrypted, padded list of private keys
uint32 checkint
uint32 checkint
byte[] privatekey1
string comment1
byte 1
byte 2
byte 3
...
byte padlen % 255
*/
const cipherName = Buffer.from(encrypted ? encrypted.cipherName : 'none');
const kdfName = Buffer.from(encrypted ? encrypted.kdfName : 'none');
const kdfOptions = (encrypted ? encrypted.kdfOptions : Buffer.alloc(0));
const blockLen = (encrypted ? encrypted.cipher.blockLen : 8);
const parsed = parseDERs(keyType, pub, priv);
const checkInt = randomBytes(4);
const commentBin = Buffer.from(comment);
const privBlobLen = (4 + 4 + parsed.priv.length + 4 + commentBin.length);
let padding = [];
for (let i = 1; ((privBlobLen + padding.length) % blockLen); ++i)
padding.push(i & 0xFF);
padding = Buffer.from(padding);
let privBlob = Buffer.allocUnsafe(privBlobLen + padding.length);
let extra;
{
let pos = 0;
privBlob.set(checkInt, pos += 0);
privBlob.set(checkInt, pos += 4);
privBlob.set(parsed.priv, pos += 4);
privBlob.writeUInt32BE(commentBin.length, pos += parsed.priv.length);
privBlob.set(commentBin, pos += 4);
privBlob.set(padding, pos += commentBin.length);
}
if (encrypted) {
const options = { authTagLength: encrypted.cipher.authLen };
const cipher = createCipheriv(
encrypted.cipher.sslName,
encrypted.key,
encrypted.iv,
options
);
cipher.setAutoPadding(false);
privBlob = Buffer.concat([ cipher.update(privBlob), cipher.final() ]);
if (encrypted.cipher.authLen > 0)
extra = cipher.getAuthTag();
else
extra = Buffer.alloc(0);
encrypted.key.fill(0);
encrypted.iv.fill(0);
} else {
extra = Buffer.alloc(0);
}
const magicBytes = Buffer.from('openssh-key-v1\0');
const privBin = Buffer.allocUnsafe(
magicBytes.length
+ 4 + cipherName.length
+ 4 + kdfName.length
+ 4 + kdfOptions.length
+ 4
+ 4 + parsed.pub.length
+ 4 + privBlob.length
+ extra.length
);
{
let pos = 0;
privBin.set(magicBytes, pos += 0);
privBin.writeUInt32BE(cipherName.length, pos += magicBytes.length);
privBin.set(cipherName, pos += 4);
privBin.writeUInt32BE(kdfName.length, pos += cipherName.length);
privBin.set(kdfName, pos += 4);
privBin.writeUInt32BE(kdfOptions.length, pos += kdfName.length);
privBin.set(kdfOptions, pos += 4);
privBin.writeUInt32BE(1, pos += kdfOptions.length);
privBin.writeUInt32BE(parsed.pub.length, pos += 4);
privBin.set(parsed.pub, pos += 4);
privBin.writeUInt32BE(privBlob.length, pos += parsed.pub.length);
privBin.set(privBlob, pos += 4);
privBin.set(extra, pos += privBlob.length);
}
{
const b64 = privBin.base64Slice(0, privBin.length);
let formatted = b64.replace(/.{64}/g, '$&\n');
if (b64.length & 63)
formatted += '\n';
privateB64 += formatted;
}
{
const b64 = parsed.pub.base64Slice(0, parsed.pub.length);
publicB64 = `${parsed.sshName} ${b64}${comment ? ` ${comment}` : ''}`;
}
privateB64 += '-----END OPENSSH PRIVATE KEY-----\n';
return {
private: privateB64,
public: publicB64,
};
}
default:
throw new Error('Invalid output key format');
}
}
function noop() {}
module.exports = {
generateKeyPair: (keyType, opts, cb) => {
if (typeof opts === 'function') {
cb = opts;
opts = undefined;
}
if (typeof cb !== 'function')
cb = noop;
const args = makeArgs(keyType, opts);
generateKeyPair_(...args, (err, pub, priv) => {
if (err)
return cb(err);
let ret;
try {
ret = convertKeys(args[0], pub, priv, opts);
} catch (ex) {
return cb(ex);
}
cb(null, ret);
});
},
generateKeyPairSync: (keyType, opts) => {
const args = makeArgs(keyType, opts);
const { publicKey: pub, privateKey: priv } = generateKeyPairSync_(...args);
return convertKeys(args[0], pub, priv, opts);
}
};