pure-js-sftp
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A pure JavaScript SFTP client with revolutionary RSA-SHA2 compatibility fixes. Zero native dependencies, built on ssh2-streams with 100% SSH key support.
279 lines (267 loc) • 10.5 kB
JavaScript
"use strict";
/**
* Pure JavaScript OpenSSH Private Key Parser
* Handles encrypted OpenSSH format keys without external dependencies
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.parseOpenSSHPrivateKey = parseOpenSSHPrivateKey;
function parseOpenSSHPrivateKey(keyData, passphrase) {
try {
// Remove header/footer and decode base64
const lines = keyData.split('\n');
const base64Data = lines
.filter(line => !line.startsWith('-----'))
.join('')
.replace(/\s/g, '');
const keyBuffer = Buffer.from(base64Data, 'base64');
// Parse OpenSSH private key format
return parseOpenSSHKeyBuffer(keyBuffer, passphrase);
}
catch (error) {
return null;
}
}
function parseOpenSSHKeyBuffer(buffer, passphrase) {
let offset = 0;
// Read magic bytes "openssh-key-v1\0"
const magic = buffer.subarray(offset, offset + 15);
if (magic.toString() !== 'openssh-key-v1\0') {
throw new Error('Invalid OpenSSH key magic');
}
offset += 15;
// Read cipher name
const cipherNameLength = buffer.readUInt32BE(offset);
offset += 4;
const cipherName = buffer.subarray(offset, offset + cipherNameLength).toString();
offset += cipherNameLength;
// Read KDF name
const kdfNameLength = buffer.readUInt32BE(offset);
offset += 4;
const kdfName = buffer.subarray(offset, offset + kdfNameLength).toString();
offset += kdfNameLength;
// Read KDF options
const kdfOptionsLength = buffer.readUInt32BE(offset);
offset += 4;
const kdfOptions = buffer.subarray(offset, offset + kdfOptionsLength);
offset += kdfOptionsLength;
// Read number of keys
const numberOfKeys = buffer.readUInt32BE(offset);
offset += 4;
if (numberOfKeys !== 1) {
throw new Error('Multiple keys not supported');
}
// Read public key
const publicKeyLength = buffer.readUInt32BE(offset);
offset += 4;
const publicKeyData = buffer.subarray(offset, offset + publicKeyLength);
offset += publicKeyLength;
// Read encrypted private key section
const encryptedLength = buffer.readUInt32BE(offset);
offset += 4;
const encryptedData = buffer.subarray(offset, offset + encryptedLength);
// Decrypt private key section
let decryptedData;
if (cipherName === 'none') {
decryptedData = encryptedData;
}
else {
if (!passphrase) {
throw new Error('Passphrase required for encrypted key');
}
decryptedData = decryptPrivateKeySection(encryptedData, cipherName, kdfName, kdfOptions, passphrase);
}
// Parse decrypted private key data
return parseDecryptedPrivateKey(decryptedData, publicKeyData);
}
function decryptPrivateKeySection(encryptedData, cipherName, kdfName, kdfOptions, passphrase) {
if (kdfName !== 'bcrypt') {
throw new Error(`Unsupported KDF: ${kdfName}`);
}
// Parse bcrypt KDF options
let offset = 0;
const saltLength = kdfOptions.readUInt32BE(offset);
offset += 4;
const salt = kdfOptions.subarray(offset, offset + saltLength);
offset += saltLength;
const rounds = kdfOptions.readUInt32BE(offset);
// Use child process for both key derivation and decryption to maintain pure JS compatibility
return decryptWithChildProcess(encryptedData, cipherName, salt, rounds, passphrase);
}
function decryptWithChildProcess(encryptedData, cipherName, salt, rounds, passphrase) {
const fs = require('fs');
const { execSync } = require('child_process');
const tempFilename = '/tmp/openssh_decrypt_' + Math.random().toString(36).substring(7) + '.js';
// Get bcrypt-pbkdf path
const bcryptPbkdfPath = require.resolve('bcrypt-pbkdf');
const decryptScript = `
const crypto = require('crypto');
const bcryptPbkdf = require('${bcryptPbkdfPath}');
try {
const input = JSON.parse(process.argv[2]);
const { encryptedData, cipherName, salt, rounds, passphrase } = input;
// Decrypt data buffer
const encryptedBuffer = Buffer.from(encryptedData, 'base64');
const saltBuffer = Buffer.from(salt, 'base64');
// Helper functions
function getCipherKeyLength(cipher) {
if (cipher.includes('256')) return 32;
if (cipher.includes('192')) return 24;
return 16;
}
function getCipherIvLength(cipher) {
return cipher.includes('gcm') ? 12 : 16;
}
function getCipherAlgorithm(cipher) {
if (cipher === 'aes256-ctr') return 'aes-256-ctr';
if (cipher === 'aes192-ctr') return 'aes-192-ctr';
if (cipher === 'aes128-ctr') return 'aes-128-ctr';
if (cipher === 'aes256-cbc') return 'aes-256-cbc';
if (cipher === 'aes192-cbc') return 'aes-192-cbc';
if (cipher === 'aes128-cbc') return 'aes-128-cbc';
throw new Error('Unsupported cipher: ' + cipher);
}
// Derive key using bcrypt-pbkdf
const keyIvLength = getCipherKeyLength(cipherName) + getCipherIvLength(cipherName);
const passphraseBuffer = Buffer.from(passphrase, 'utf8');
const derivedKey = Buffer.alloc(keyIvLength);
// bcrypt-pbkdf v1.0.2 API: bcrypt_pbkdf(pass, passlen, salt, saltlen, key, keylen, rounds)
const result = bcryptPbkdf.pbkdf(
passphraseBuffer, // pass
passphraseBuffer.length, // passlen
saltBuffer, // salt
saltBuffer.length, // saltlen
derivedKey, // key (output buffer)
derivedKey.length, // keylen
rounds // rounds
);
if (result !== 0) {
throw new Error('bcrypt-pbkdf key derivation failed with code: ' + result);
}
const keyLength = getCipherKeyLength(cipherName);
const ivLength = getCipherIvLength(cipherName);
const key = derivedKey.subarray(0, keyLength);
const iv = derivedKey.subarray(keyLength, keyLength + ivLength);
// Decrypt
const decipher = crypto.createDecipheriv(getCipherAlgorithm(cipherName), key, iv);
decipher.setAutoPadding(false);
let decrypted = decipher.update(encryptedBuffer);
const final = decipher.final();
decrypted = Buffer.concat([decrypted, final]);
process.stdout.write(decrypted.toString('base64'));
} catch (error) {
process.stderr.write('DECRYPT_ERROR: ' + error.message);
process.exit(1);
}
`;
try {
fs.writeFileSync(tempFilename, decryptScript);
const input = {
encryptedData: encryptedData.toString('base64'),
cipherName,
salt: salt.toString('base64'),
rounds,
passphrase
};
const result = execSync(`node "${tempFilename}" '${JSON.stringify(input)}'`, {
encoding: 'utf8',
timeout: 10000,
maxBuffer: 10 * 1024 * 1024 // 10MB
});
fs.unlinkSync(tempFilename);
return Buffer.from(result, 'base64');
}
catch (error) {
try {
fs.unlinkSync(tempFilename);
}
catch { }
throw new Error('OpenSSH decryption failed in child process: ' + (error instanceof Error ? error.message : String(error)));
}
}
function parseDecryptedPrivateKey(decryptedData, publicKeyData) {
let offset = 0;
// Read check bytes (should be identical)
const check1 = decryptedData.readUInt32BE(offset);
offset += 4;
const check2 = decryptedData.readUInt32BE(offset);
offset += 4;
if (check1 !== check2) {
throw new Error('Invalid passphrase or corrupted key');
}
// Read key type
const keyTypeLength = decryptedData.readUInt32BE(offset);
offset += 4;
const keyType = decryptedData.subarray(offset, offset + keyTypeLength).toString();
offset += keyTypeLength;
// The rest depends on key type, but for SSH public key generation,
// we primarily need the public key data which we already have
// Read public key parameters (key-type specific)
let privateKeyData;
let comment = '';
if (keyType === 'ssh-rsa') {
// RSA: n, e, d, iqmp, p, q
const nLength = decryptedData.readUInt32BE(offset);
offset += 4;
const n = decryptedData.subarray(offset, offset + nLength);
offset += nLength;
const eLength = decryptedData.readUInt32BE(offset);
offset += 4;
const e = decryptedData.subarray(offset, offset + eLength);
offset += eLength;
const dLength = decryptedData.readUInt32BE(offset);
offset += 4;
const d = decryptedData.subarray(offset, offset + dLength);
offset += dLength;
// Skip iqmp, p, q for now
privateKeyData = Buffer.concat([n, e, d]);
}
else if (keyType === 'ssh-ed25519') {
// Ed25519: public key (32 bytes) + private key (32 bytes)
const pubLength = decryptedData.readUInt32BE(offset);
offset += 4;
const pub = decryptedData.subarray(offset, offset + pubLength);
offset += pubLength;
const privLength = decryptedData.readUInt32BE(offset);
offset += 4;
const priv = decryptedData.subarray(offset, offset + privLength);
offset += privLength;
privateKeyData = Buffer.concat([pub, priv]);
}
else if (keyType.startsWith('ecdsa-sha2-')) {
// ECDSA: curve name + public key + private key
const curveLength = decryptedData.readUInt32BE(offset);
offset += 4;
const curve = decryptedData.subarray(offset, offset + curveLength);
offset += curveLength;
const pubLength = decryptedData.readUInt32BE(offset);
offset += 4;
const pub = decryptedData.subarray(offset, offset + pubLength);
offset += pubLength;
const privLength = decryptedData.readUInt32BE(offset);
offset += 4;
const priv = decryptedData.subarray(offset, offset + privLength);
offset += privLength;
privateKeyData = Buffer.concat([curve, pub, priv]);
}
else {
throw new Error(`Unsupported key type: ${keyType}`);
}
// Read comment
try {
const commentLength = decryptedData.readUInt32BE(offset);
offset += 4;
comment = decryptedData.subarray(offset, offset + commentLength).toString();
}
catch (e) {
// Comment might not be present or readable
comment = '';
}
return {
keyType,
publicKey: publicKeyData,
privateKey: privateKeyData,
comment
};
}
// Helper functions moved to child process for pure JS compatibility
//# sourceMappingURL=openssh-key-parser.js.map