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utils.js (2839B)

      1 // Copyright 2012 Joyent, Inc.  All rights reserved.
      2 
      3 var assert = require('assert-plus');
      4 var sshpk = require('sshpk');
      5 var util = require('util');
      6 
      7 var HASH_ALGOS = {
      8   'sha1': true,
      9   'sha256': true,
     10   'sha512': true
     11 };
     12 
     13 var PK_ALGOS = {
     14   'rsa': true,
     15   'dsa': true,
     16   'ecdsa': true
     17 };
     18 
     19 function HttpSignatureError(message, caller) {
     20   if (Error.captureStackTrace)
     21     Error.captureStackTrace(this, caller || HttpSignatureError);
     22 
     23   this.message = message;
     24   this.name = caller.name;
     25 }
     26 util.inherits(HttpSignatureError, Error);
     27 
     28 function InvalidAlgorithmError(message) {
     29   HttpSignatureError.call(this, message, InvalidAlgorithmError);
     30 }
     31 util.inherits(InvalidAlgorithmError, HttpSignatureError);
     32 
     33 function validateAlgorithm(algorithm) {
     34   var alg = algorithm.toLowerCase().split('-');
     35 
     36   if (alg.length !== 2) {
     37     throw (new InvalidAlgorithmError(alg[0].toUpperCase() + ' is not a ' +
     38       'valid algorithm'));
     39   }
     40 
     41   if (alg[0] !== 'hmac' && !PK_ALGOS[alg[0]]) {
     42     throw (new InvalidAlgorithmError(alg[0].toUpperCase() + ' type keys ' +
     43       'are not supported'));
     44   }
     45 
     46   if (!HASH_ALGOS[alg[1]]) {
     47     throw (new InvalidAlgorithmError(alg[1].toUpperCase() + ' is not a ' +
     48       'supported hash algorithm'));
     49   }
     50 
     51   return (alg);
     52 }
     53 
     54 ///--- API
     55 
     56 module.exports = {
     57 
     58   HASH_ALGOS: HASH_ALGOS,
     59   PK_ALGOS: PK_ALGOS,
     60 
     61   HttpSignatureError: HttpSignatureError,
     62   InvalidAlgorithmError: InvalidAlgorithmError,
     63 
     64   validateAlgorithm: validateAlgorithm,
     65 
     66   /**
     67    * Converts an OpenSSH public key (rsa only) to a PKCS#8 PEM file.
     68    *
     69    * The intent of this module is to interoperate with OpenSSL only,
     70    * specifically the node crypto module's `verify` method.
     71    *
     72    * @param {String} key an OpenSSH public key.
     73    * @return {String} PEM encoded form of the RSA public key.
     74    * @throws {TypeError} on bad input.
     75    * @throws {Error} on invalid ssh key formatted data.
     76    */
     77   sshKeyToPEM: function sshKeyToPEM(key) {
     78     assert.string(key, 'ssh_key');
     79 
     80     var k = sshpk.parseKey(key, 'ssh');
     81     return (k.toString('pem'));
     82   },
     83 
     84 
     85   /**
     86    * Generates an OpenSSH fingerprint from an ssh public key.
     87    *
     88    * @param {String} key an OpenSSH public key.
     89    * @return {String} key fingerprint.
     90    * @throws {TypeError} on bad input.
     91    * @throws {Error} if what you passed doesn't look like an ssh public key.
     92    */
     93   fingerprint: function fingerprint(key) {
     94     assert.string(key, 'ssh_key');
     95 
     96     var k = sshpk.parseKey(key, 'ssh');
     97     return (k.fingerprint('md5').toString('hex'));
     98   },
     99 
    100   /**
    101    * Converts a PKGCS#8 PEM file to an OpenSSH public key (rsa)
    102    *
    103    * The reverse of the above function.
    104    */
    105   pemToRsaSSHKey: function pemToRsaSSHKey(pem, comment) {
    106     assert.equal('string', typeof (pem), 'typeof pem');
    107 
    108     var k = sshpk.parseKey(pem, 'pem');
    109     k.comment = comment;
    110     return (k.toString('ssh'));
    111   }
    112 };