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node_modules/sshpk/lib/formats/putty.js

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+// Copyright 2018 Joyent, Inc.
+
+module.exports = {
+	read: read,
+	write: write
+};
+
+var assert = require('assert-plus');
+var Buffer = require('safer-buffer').Buffer;
+var rfc4253 = require('./rfc4253');
+var Key = require('../key');
+var SSHBuffer = require('../ssh-buffer');
+var crypto = require('crypto');
+var PrivateKey = require('../private-key');
+
+var errors = require('../errors');
+
+// https://tartarus.org/~simon/putty-prerel-snapshots/htmldoc/AppendixC.html
+function read(buf, options) {
+	var lines = buf.toString('ascii').split(/[\r\n]+/);
+	var found = false;
+	var parts;
+	var si = 0;
+	var formatVersion;
+	while (si < lines.length) {
+		parts = splitHeader(lines[si++]);
+		if (parts) {
+			formatVersion = {
+				'putty-user-key-file-2': 2,
+				'putty-user-key-file-3': 3
+			}[parts[0].toLowerCase()];
+			if (formatVersion) {
+				found = true;
+				break;
+			}
+		}
+	}
+	if (!found) {
+		throw (new Error('No PuTTY format first line found'));
+	}
+	var alg = parts[1];
+
+	parts = splitHeader(lines[si++]);
+	assert.equal(parts[0].toLowerCase(), 'encryption');
+	var encryption = parts[1];
+
+	parts = splitHeader(lines[si++]);
+	assert.equal(parts[0].toLowerCase(), 'comment');
+	var comment = parts[1];
+
+	parts = splitHeader(lines[si++]);
+	assert.equal(parts[0].toLowerCase(), 'public-lines');
+	var publicLines = parseInt(parts[1], 10);
+	if (!isFinite(publicLines) || publicLines < 0 ||
+	    publicLines > lines.length) {
+		throw (new Error('Invalid public-lines count'));
+	}
+
+	var publicBuf = Buffer.from(
+	    lines.slice(si, si + publicLines).join(''), 'base64');
+	var keyType = rfc4253.algToKeyType(alg);
+	var key = rfc4253.read(publicBuf);
+	if (key.type !== keyType) {
+		throw (new Error('Outer key algorithm mismatch'));
+	}
+
+	si += publicLines;
+	if (lines[si]) {
+		parts = splitHeader(lines[si++]);
+		assert.equal(parts[0].toLowerCase(), 'private-lines');
+		var privateLines = parseInt(parts[1], 10);
+		if (!isFinite(privateLines) || privateLines < 0 ||
+		    privateLines > lines.length) {
+			throw (new Error('Invalid private-lines count'));
+		}
+
+		var privateBuf = Buffer.from(
+			lines.slice(si, si + privateLines).join(''), 'base64');
+
+		if (encryption !== 'none' && formatVersion === 3) {
+			throw new Error('Encrypted keys arenot supported for' +
+			' PuTTY format version 3');
+		}
+
+		if (encryption === 'aes256-cbc') {
+			if (!options.passphrase) {
+				throw (new errors.KeyEncryptedError(
+					options.filename, 'PEM'));
+			}
+
+			var iv = Buffer.alloc(16, 0);
+			var decipher = crypto.createDecipheriv(
+				'aes-256-cbc',
+				derivePPK2EncryptionKey(options.passphrase),
+				iv);
+			decipher.setAutoPadding(false);
+			privateBuf = Buffer.concat([
+				decipher.update(privateBuf), decipher.final()]);
+		}
+
+		key = new PrivateKey(key);
+		if (key.type !== keyType) {
+			throw (new Error('Outer key algorithm mismatch'));
+		}
+
+		var sshbuf = new SSHBuffer({buffer: privateBuf});
+		var privateKeyParts;
+		if (alg === 'ssh-dss') {
+			privateKeyParts = [ {
+				name: 'x',
+				data: sshbuf.readBuffer()
+			}];
+		} else if (alg === 'ssh-rsa') {
+			privateKeyParts = [
+				{ name: 'd', data: sshbuf.readBuffer() },
+				{ name: 'p', data: sshbuf.readBuffer() },
+				{ name: 'q', data: sshbuf.readBuffer() },
+				{ name: 'iqmp', data: sshbuf.readBuffer() }
+			];
+		} else if (alg.match(/^ecdsa-sha2-nistp/)) {
+			privateKeyParts = [ {
+				name: 'd', data: sshbuf.readBuffer()
+			} ];
+		} else if (alg === 'ssh-ed25519') {
+			privateKeyParts = [ {
+				name: 'k', data: sshbuf.readBuffer()
+			} ];
+		} else {
+			throw new Error('Unsupported PPK key type: ' + alg);
+		}
+
+		key = new PrivateKey({
+			type: key.type,
+			parts: key.parts.concat(privateKeyParts)
+		});
+	}
+
+	key.comment = comment;
+	return (key);
+}
+
+function derivePPK2EncryptionKey(passphrase) {
+	var hash1 = crypto.createHash('sha1').update(Buffer.concat([
+		Buffer.from([0, 0, 0, 0]),
+		Buffer.from(passphrase)
+	])).digest();
+	var hash2 = crypto.createHash('sha1').update(Buffer.concat([
+		Buffer.from([0, 0, 0, 1]),
+		Buffer.from(passphrase)
+	])).digest();
+	return (Buffer.concat([hash1, hash2]).slice(0, 32));
+}
+
+function splitHeader(line) {
+	var idx = line.indexOf(':');
+	if (idx === -1)
+		return (null);
+	var header = line.slice(0, idx);
+	++idx;
+	while (line[idx] === ' ')
+		++idx;
+	var rest = line.slice(idx);
+	return ([header, rest]);
+}
+
+function write(key, options) {
+	assert.object(key);
+	if (!Key.isKey(key))
+		throw (new Error('Must be a public key'));
+
+	var alg = rfc4253.keyTypeToAlg(key);
+	var buf = rfc4253.write(key);
+	var comment = key.comment || '';
+
+	var b64 = buf.toString('base64');
+	var lines = wrap(b64, 64);
+
+	lines.unshift('Public-Lines: ' + lines.length);
+	lines.unshift('Comment: ' + comment);
+	lines.unshift('Encryption: none');
+	lines.unshift('PuTTY-User-Key-File-2: ' + alg);
+
+	return (Buffer.from(lines.join('\n') + '\n'));
+}
+
+function wrap(txt, len) {
+	var lines = [];
+	var pos = 0;
+	while (pos < txt.length) {
+		lines.push(txt.slice(pos, pos + 64));
+		pos += 64;
+	}
+	return (lines);
+}