Importing OpenSSH private key

Author: ondralukes

src/formats/formats.js

@@ -31,6 +31,7 @@ module.exports = {
     pkcs1: require('./pkcs1'),
     pkcs8: require('./pkcs8'),
     components: require('./components'),
+    openssh: require('./openssh'),
 
     isPrivateExport: function (format) {
         return module.exports[format] && typeof module.exports[format].privateExport === 'function';

src/formats/openssh.js

@@ -0,0 +1,123 @@
+var _ = require('../utils')._;
+var utils = require('../utils');
+var BigInteger = require('../libs/jsbn');
+
+const PRIVATE_OPENING_BOUNDARY = '-----BEGIN OPENSSH PRIVATE KEY-----';
+const PRIVATE_CLOSING_BOUNDARY = '-----END OPENSSH PRIVATE KEY-----';
+
+module.exports = {
+    privateExport: function (key, options) {
+        throw Error('Not implemented yet.');
+    },
+
+    privateImport: function (key, data, options) {
+        options = options || {};
+        var buffer;
+
+        if (options.type !== 'der') {
+            if (Buffer.isBuffer(data)) {
+                data = data.toString('utf8');
+            }
+
+            if (_.isString(data)) {
+                var pem = utils.trimSurroundingText(data, PRIVATE_OPENING_BOUNDARY, PRIVATE_CLOSING_BOUNDARY)
+                    .replace(/\s+|\n\r|\n|\r$/gm, '');
+                buffer = Buffer.from(pem, 'base64');
+            } else {
+                throw Error('Unsupported key format');
+            }
+        } else if (Buffer.isBuffer(data)) {
+            buffer = data;
+        } else {
+            throw Error('Unsupported key format');
+        }
+
+        const reader = {buf:buffer, off:0};
+
+        if(buffer.slice(0,14).toString('ascii') !== 'openssh-key-v1')
+            throw 'Invalid file format.';
+
+        reader.off += 15;
+
+        //ciphername
+        if(readOpenSSHKeyString(reader).toString('ascii') !== 'none')
+            throw Error('Unsupported key type');
+        //kdfname
+        if(readOpenSSHKeyString(reader).toString('ascii') !== 'none')
+            throw Error('Unsupported key type');
+        //kdf
+        if(readOpenSSHKeyString(reader).toString('ascii') !== '')
+            throw Error('Unsupported key type');
+        //keynum
+        reader.off += 4;
+
+        //sshpublengtn
+        reader.off += 4;
+
+        //keytype
+        if(readOpenSSHKeyString(reader).toString('ascii') !== 'ssh-rsa')
+            throw Error('Unsupported key type');
+        readOpenSSHKeyString(reader);
+        readOpenSSHKeyString(reader);
+
+        reader.off += 12;
+        if(readOpenSSHKeyString(reader).toString('ascii') !== 'ssh-rsa')
+            throw Error('Unsupported key type');
+
+        const n = readOpenSSHKeyString(reader);
+        const e = readOpenSSHKeyString(reader);
+        const d = readOpenSSHKeyString(reader);
+        const coeff = readOpenSSHKeyString(reader);
+        const p = readOpenSSHKeyString(reader);
+        const q = readOpenSSHKeyString(reader);
+
+        //Calculate missing values
+        const dint = new BigInteger(d);
+        const qint = new BigInteger(q);
+        const pint = new BigInteger(p);
+        const dp = dint.mod(pint.subtract(BigInteger.ONE));
+        const dq = dint.mod(qint.subtract(BigInteger.ONE));
+
+        key.setPrivate(
+            n,  // modulus
+            e,  // publicExponent
+            d,  // privateExponent
+            p,  // prime1
+            q,  // prime2
+            dp.toBuffer(),  // exponent1 -- d mod (p1)
+            dq.toBuffer(),  // exponent2 -- d mod (q-1)
+            coeff  // coefficient -- (inverse of q) mod p
+        );
+    },
+
+    publicExport: function (key, options) {
+        throw Error('Not implemented yet.');
+    },
+
+    publicImport: function (key, data, options) {
+        throw Error('Not implemented yet.');
+    },
+
+    /**
+     * Trying autodetect and import key
+     * @param key
+     * @param data
+     */
+    autoImport: function (key, data) {
+        // [\S\s]* matches zero or more of any character
+        if (/^[\S\s]*-----BEGIN OPENSSH PRIVATE KEY-----\s*(?=(([A-Za-z0-9+/=]+\s*)+))\1-----END OPENSSH PRIVATE KEY-----[\S\s]*$/g.test(data)) {
+            module.exports.privateImport(key, data);
+            return true;
+        }
+
+        return false;
+    }
+};
+
+function readOpenSSHKeyString(reader) {
+    const len = reader.buf.readInt32BE(reader.off);
+    reader.off += 4;
+    const res = reader.buf.slice(reader.off, reader.off + len);
+    reader.off += len;
+    return res;
+}