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1// Copyright 2017 Joyent, Inc.
2
3module.exports = PrivateKey;
4
5var assert = require('assert-plus');
6var Buffer = require('safer-buffer').Buffer;
7var algs = require('./algs');
8var crypto = require('crypto');
9var Fingerprint = require('./fingerprint');
10var Signature = require('./signature');
11var errs = require('./errors');
12var util = require('util');
13var utils = require('./utils');
14var dhe = require('./dhe');
15var generateECDSA = dhe.generateECDSA;
16var generateED25519 = dhe.generateED25519;
17var edCompat;
18var nacl;
19
20try {
21	edCompat = require('./ed-compat');
22} catch (e) {
23	/* Just continue through, and bail out if we try to use it. */
24}
25
26var Key = require('./key');
27
28var InvalidAlgorithmError = errs.InvalidAlgorithmError;
29var KeyParseError = errs.KeyParseError;
30var KeyEncryptedError = errs.KeyEncryptedError;
31
32var formats = {};
33formats['auto'] = require('./formats/auto');
34formats['pem'] = require('./formats/pem');
35formats['pkcs1'] = require('./formats/pkcs1');
36formats['pkcs8'] = require('./formats/pkcs8');
37formats['rfc4253'] = require('./formats/rfc4253');
38formats['ssh-private'] = require('./formats/ssh-private');
39formats['openssh'] = formats['ssh-private'];
40formats['ssh'] = formats['ssh-private'];
41formats['dnssec'] = require('./formats/dnssec');
42
43function PrivateKey(opts) {
44	assert.object(opts, 'options');
45	Key.call(this, opts);
46
47	this._pubCache = undefined;
48}
49util.inherits(PrivateKey, Key);
50
51PrivateKey.formats = formats;
52
53PrivateKey.prototype.toBuffer = function (format, options) {
54	if (format === undefined)
55		format = 'pkcs1';
56	assert.string(format, 'format');
57	assert.object(formats[format], 'formats[format]');
58	assert.optionalObject(options, 'options');
59
60	return (formats[format].write(this, options));
61};
62
63PrivateKey.prototype.hash = function (algo) {
64	return (this.toPublic().hash(algo));
65};
66
67PrivateKey.prototype.toPublic = function () {
68	if (this._pubCache)
69		return (this._pubCache);
70
71	var algInfo = algs.info[this.type];
72	var pubParts = [];
73	for (var i = 0; i < algInfo.parts.length; ++i) {
74		var p = algInfo.parts[i];
75		pubParts.push(this.part[p]);
76	}
77
78	this._pubCache = new Key({
79		type: this.type,
80		source: this,
81		parts: pubParts
82	});
83	if (this.comment)
84		this._pubCache.comment = this.comment;
85	return (this._pubCache);
86};
87
88PrivateKey.prototype.derive = function (newType) {
89	assert.string(newType, 'type');
90	var priv, pub, pair;
91
92	if (this.type === 'ed25519' && newType === 'curve25519') {
93		if (nacl === undefined)
94			nacl = require('tweetnacl');
95
96		priv = this.part.k.data;
97		if (priv[0] === 0x00)
98			priv = priv.slice(1);
99
100		pair = nacl.box.keyPair.fromSecretKey(new Uint8Array(priv));
101		pub = Buffer.from(pair.publicKey);
102
103		return (new PrivateKey({
104			type: 'curve25519',
105			parts: [
106				{ name: 'A', data: utils.mpNormalize(pub) },
107				{ name: 'k', data: utils.mpNormalize(priv) }
108			]
109		}));
110	} else if (this.type === 'curve25519' && newType === 'ed25519') {
111		if (nacl === undefined)
112			nacl = require('tweetnacl');
113
114		priv = this.part.k.data;
115		if (priv[0] === 0x00)
116			priv = priv.slice(1);
117
118		pair = nacl.sign.keyPair.fromSeed(new Uint8Array(priv));
119		pub = Buffer.from(pair.publicKey);
120
121		return (new PrivateKey({
122			type: 'ed25519',
123			parts: [
124				{ name: 'A', data: utils.mpNormalize(pub) },
125				{ name: 'k', data: utils.mpNormalize(priv) }
126			]
127		}));
128	}
129	throw (new Error('Key derivation not supported from ' + this.type +
130	    ' to ' + newType));
131};
132
133PrivateKey.prototype.createVerify = function (hashAlgo) {
134	return (this.toPublic().createVerify(hashAlgo));
135};
136
137PrivateKey.prototype.createSign = function (hashAlgo) {
138	if (hashAlgo === undefined)
139		hashAlgo = this.defaultHashAlgorithm();
140	assert.string(hashAlgo, 'hash algorithm');
141
142	/* ED25519 is not supported by OpenSSL, use a javascript impl. */
143	if (this.type === 'ed25519' && edCompat !== undefined)
144		return (new edCompat.Signer(this, hashAlgo));
145	if (this.type === 'curve25519')
146		throw (new Error('Curve25519 keys are not suitable for ' +
147		    'signing or verification'));
148
149	var v, nm, err;
150	try {
151		nm = hashAlgo.toUpperCase();
152		v = crypto.createSign(nm);
153	} catch (e) {
154		err = e;
155	}
156	if (v === undefined || (err instanceof Error &&
157	    err.message.match(/Unknown message digest/))) {
158		nm = 'RSA-';
159		nm += hashAlgo.toUpperCase();
160		v = crypto.createSign(nm);
161	}
162	assert.ok(v, 'failed to create verifier');
163	var oldSign = v.sign.bind(v);
164	var key = this.toBuffer('pkcs1');
165	var type = this.type;
166	var curve = this.curve;
167	v.sign = function () {
168		var sig = oldSign(key);
169		if (typeof (sig) === 'string')
170			sig = Buffer.from(sig, 'binary');
171		sig = Signature.parse(sig, type, 'asn1');
172		sig.hashAlgorithm = hashAlgo;
173		sig.curve = curve;
174		return (sig);
175	};
176	return (v);
177};
178
179PrivateKey.parse = function (data, format, options) {
180	if (typeof (data) !== 'string')
181		assert.buffer(data, 'data');
182	if (format === undefined)
183		format = 'auto';
184	assert.string(format, 'format');
185	if (typeof (options) === 'string')
186		options = { filename: options };
187	assert.optionalObject(options, 'options');
188	if (options === undefined)
189		options = {};
190	assert.optionalString(options.filename, 'options.filename');
191	if (options.filename === undefined)
192		options.filename = '(unnamed)';
193
194	assert.object(formats[format], 'formats[format]');
195
196	try {
197		var k = formats[format].read(data, options);
198		assert.ok(k instanceof PrivateKey, 'key is not a private key');
199		if (!k.comment)
200			k.comment = options.filename;
201		return (k);
202	} catch (e) {
203		if (e.name === 'KeyEncryptedError')
204			throw (e);
205		throw (new KeyParseError(options.filename, format, e));
206	}
207};
208
209PrivateKey.isPrivateKey = function (obj, ver) {
210	return (utils.isCompatible(obj, PrivateKey, ver));
211};
212
213PrivateKey.generate = function (type, options) {
214	if (options === undefined)
215		options = {};
216	assert.object(options, 'options');
217
218	switch (type) {
219	case 'ecdsa':
220		if (options.curve === undefined)
221			options.curve = 'nistp256';
222		assert.string(options.curve, 'options.curve');
223		return (generateECDSA(options.curve));
224	case 'ed25519':
225		return (generateED25519());
226	default:
227		throw (new Error('Key generation not supported with key ' +
228		    'type "' + type + '"'));
229	}
230};
231
232/*
233 * API versions for PrivateKey:
234 * [1,0] -- initial ver
235 * [1,1] -- added auto, pkcs[18], openssh/ssh-private formats
236 * [1,2] -- added defaultHashAlgorithm
237 * [1,3] -- added derive, ed, createDH
238 * [1,4] -- first tagged version
239 * [1,5] -- changed ed25519 part names and format
240 */
241PrivateKey.prototype._sshpkApiVersion = [1, 5];
242
243PrivateKey._oldVersionDetect = function (obj) {
244	assert.func(obj.toPublic);
245	assert.func(obj.createSign);
246	if (obj.derive)
247		return ([1, 3]);
248	if (obj.defaultHashAlgorithm)
249		return ([1, 2]);
250	if (obj.formats['auto'])
251		return ([1, 1]);
252	return ([1, 0]);
253};
254