acme.js/lib/csr.js

// Copyright 2018-present AJ ONeal. All rights reserved
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
(function (exports) {
'use strict';
/*global Promise*/

var ASN1 = exports.ASN1;
var Enc = exports.Enc;
var PEM = exports.PEM;
var X509 = exports.x509;
var Keypairs = exports.Keypairs;

// TODO find a way that the prior node-ish way of `module.exports = function () {}` isn't broken
var CSR = exports.CSR = function (opts) {
  // We're using a Promise here to be compatible with the browser version
  // which will probably use the webcrypto API for some of the conversions
  return CSR._prepare(opts).then(function (opts) {
    return CSR.create(opts).then(function (bytes) {
      return CSR._encode(opts, bytes);
    });
  });
};

CSR._prepare = function (opts) {
  return Promise.resolve().then(function () {
    var Keypairs;
    opts = JSON.parse(JSON.stringify(opts));

    // We do a bit of extra error checking for user convenience
    if (!opts) { throw new Error("You must pass options with key and domains to rsacsr"); }
    if (!Array.isArray(opts.domains) || 0 === opts.domains.length) {
      new Error("You must pass options.domains as a non-empty array");
    }

    // I need to check that 例.中国 is a valid domain name
    if (!opts.domains.every(function (d) {
      // allow punycode? xn--
      if ('string' === typeof d /*&& /\./.test(d) && !/--/.test(d)*/) {
        return true;
      }
    })) {
      throw new Error("You must pass options.domains as strings");
    }

    if (opts.jwk) { return opts; }
    if (opts.key && opts.key.kty) {
      opts.jwk = opts.key;
      return opts;
    }
    if (!opts.pem && !opts.key) {
      throw new Error("You must pass options.key as a JSON web key");
    }

    Keypairs = exports.Keypairs;
    if (!exports.Keypairs) {
      throw new Error("Keypairs.js is an optional dependency for PEM-to-JWK.\n"
        + "Install it if you'd like to use it:\n"
        + "\tnpm install --save rasha\n"
        + "Otherwise supply a jwk as the private key."
      );
    }

    return Keypairs.import({ pem: opts.pem || opts.key }).then(function (pair) {
      opts.jwk = pair.private;
      return opts;
    });
  });
};

CSR._encode = function (opts, bytes) {
  if ('der' === (opts.encoding||'').toLowerCase()) {
    return bytes;
  }
  return PEM.packBlock({
    type: "CERTIFICATE REQUEST"
  , bytes: bytes /* { jwk: jwk, domains: opts.domains } */
  });
};

CSR.create = function createCsr(opts) {
  var hex = CSR.request(opts.jwk, opts.domains);
  return CSR._sign(opts.jwk, hex).then(function (csr) {
    return Enc.hexToBuf(csr);
  });
};

//
// EC / RSA
//
CSR.request = function createCsrBodyEc(jwk, domains) {
  var asn1pub;
  if (/^EC/i.test(jwk.kty)) {
    asn1pub = X509.packCsrEcPublicKey(jwk);
  } else {
    asn1pub = X509.packCsrRsaPublicKey(jwk);
  }
  return X509.packCsr(asn1pub, domains);
};

CSR._sign = function csrEcSig(jwk, request) {
  // Took some tips from https://gist.github.com/codermapuche/da4f96cdb6d5ff53b7ebc156ec46a10a
  // TODO will have to convert web ECDSA signatures to PEM ECDSA signatures (but RSA should be the same)
  // TODO have a consistent non-private way to sign
  return Keypairs._sign({ jwk: jwk, format: 'x509' }, Enc.hexToBuf(request)).then(function (sig) {
    return CSR._toDer({ request: request, signature: sig, kty: jwk.kty });
  });
};

CSR._toDer = function encode(opts) {
  var sty;
  if (/^EC/i.test(opts.kty)) {
    // 1.2.840.10045.4.3.2 ecdsaWithSHA256 (ANSI X9.62 ECDSA algorithm with SHA256)
    sty = ASN1('30', ASN1('06', '2a8648ce3d040302'));
  } else {
    // 1.2.840.113549.1.1.11 sha256WithRSAEncryption (PKCS #1)
    sty = ASN1('30', ASN1('06', '2a864886f70d01010b'), ASN1('05'));
  }
  return ASN1('30'
    // The Full CSR Request Body
  , opts.request
    // The Signature Type
  , sty
    // The Signature
  , ASN1.BitStr(Enc.bufToHex(opts.signature))
  );
};

X509.packCsr = function (asn1pubkey, domains) {
  return ASN1('30'
    // Version (0)
  , ASN1.UInt('00')

    // 2.5.4.3 commonName (X.520 DN component)
  , ASN1('30', ASN1('31', ASN1('30', ASN1('06', '550403'), ASN1('0c', Enc.utf8ToHex(domains[0])))))

    // Public Key (RSA or EC)
  , asn1pubkey

    // Request Body
  , ASN1('a0'
    , ASN1('30'
        // 1.2.840.113549.1.9.14 extensionRequest (PKCS #9 via CRMF)
      , ASN1('06', '2a864886f70d01090e')
      , ASN1('31'
        , ASN1('30'
          , ASN1('30'
              // 2.5.29.17 subjectAltName (X.509 extension)
            , ASN1('06', '551d11')
            , ASN1('04'
              , ASN1('30', domains.map(function (d) {
                  return ASN1('82', Enc.utf8ToHex(d));
                }).join(''))))))))
  );
};

// TODO finish this later
// we want to parse the domains, the public key, and verify the signature
CSR._info = function (der) {
  // standard base64 PEM
  if ('string' === typeof der && '-' === der[0]) {
    der = PEM.parseBlock(der).bytes;
  }
  // jose urlBase64 not-PEM
  if ('string' === typeof der) {
    der = Enc.base64ToBuf(der);
  }
  // not supporting binary-encoded bas64
  var c = ASN1.parse(der);
  var kty;
  // A cert has 3 parts: cert, signature meta, signature
  if (c.children.length !== 3) {
    throw new Error("doesn't look like a certificate request: expected 3 parts of header");
  }
  var sig = c.children[2];
  if (sig.children.length) {
    // ASN1/X509 EC
    sig = sig.children[0];
    sig = ASN1('30', ASN1.UInt(Enc.bufToHex(sig.children[0].value)), ASN1.UInt(Enc.bufToHex(sig.children[1].value)));
    sig = Enc.hexToBuf(sig);
    kty = 'EC';
  } else {
    // Raw RSA Sig
    sig = sig.value;
    kty = 'RSA';
  }
  //c.children[1]; // signature type
  var req = c.children[0];
  // TODO utf8
  if (4 !== req.children.length) {
    throw new Error("doesn't look like a certificate request: expected 4 parts to request");
  }
  // 0 null
  // 1 commonName / subject
  var sub = Enc.bufToBin(req.children[1].children[0].children[0].children[1].value);
  // 3 public key (type, key)
  //console.log('oid', Enc.bufToHex(req.children[2].children[0].children[0].value));
  var pub;
  // TODO reuse ASN1 parser for these?
  if ('EC' === kty) {
    // throw away compression byte
    pub = req.children[2].children[1].value.slice(1);
    pub = { kty: kty, x: pub.slice(0, 32), y: pub.slice(32) };
    while (0 === pub.x[0]) { pub.x = pub.x.slice(1); }
    while (0 === pub.y[0]) { pub.y = pub.y.slice(1); }
    if ((pub.x.length || pub.x.byteLength) > 48) {
      pub.crv = 'P-521';
    } else if ((pub.x.length || pub.x.byteLength) > 32) {
      pub.crv = 'P-384';
    } else {
      pub.crv = 'P-256';
    }
    pub.x = Enc.bufToUrlBase64(pub.x);
    pub.y = Enc.bufToUrlBase64(pub.y);
  } else {
    pub = req.children[2].children[1].children[0];
    pub = { kty: kty, n: pub.children[0].value, e: pub.children[1].value };
    while (0 === pub.n[0]) { pub.n = pub.n.slice(1); }
    while (0 === pub.e[0]) { pub.e = pub.e.slice(1); }
    pub.n = Enc.bufToUrlBase64(pub.n);
    pub.e = Enc.bufToUrlBase64(pub.e);
  }
  // 4 extensions
  var domains = req.children[3].children.filter(function (seq) {
    //  1.2.840.113549.1.9.14 extensionRequest (PKCS #9 via CRMF)
    if ('2a864886f70d01090e' === Enc.bufToHex(seq.children[0].value)) {
      return true;
    }
  }).map(function (seq) {
    return seq.children[1].children[0].children.filter(function (seq2) {
      // subjectAltName (X.509 extension)
      if ('551d11' === Enc.bufToHex(seq2.children[0].value)) {
        return true;
      }
    }).map(function (seq2) {
      return seq2.children[1].children[0].children.map(function (name) {
        // TODO utf8
        return Enc.bufToBin(name.value);
      });
    })[0];
  })[0];

  return {
    subject: sub
  , altnames: domains
  , jwk: pub
  , signature: sig
  };
};

X509.packCsrRsaPublicKey = function (jwk) {
  // Sequence the key
  var n = ASN1.UInt(Enc.base64ToHex(jwk.n));
  var e = ASN1.UInt(Enc.base64ToHex(jwk.e));
  var asn1pub = ASN1('30', n, e);

  // Add the CSR pub key header
  return ASN1('30', ASN1('30', ASN1('06', '2a864886f70d010101'), ASN1('05')), ASN1.BitStr(asn1pub));
};

X509.packCsrEcPublicKey = function (jwk) {
  var ecOid = X509._oids[jwk.crv];
  if (!ecOid) {
    throw new Error("Unsupported namedCurve '" + jwk.crv + "'. Supported types are " + Object.keys(X509._oids));
  }
  var cmp = '04'; // 04 == x+y, 02 == x-only
  var hxy = '';
  // Placeholder. I'm not even sure if compression should be supported.
  if (!jwk.y) { cmp = '02'; }
  hxy += Enc.base64ToHex(jwk.x);
  if (jwk.y) { hxy += Enc.base64ToHex(jwk.y); }

  // 1.2.840.10045.2.1 ecPublicKey
  return ASN1('30', ASN1('30', ASN1('06', '2a8648ce3d0201'), ASN1('06', ecOid)), ASN1.BitStr(cmp + hxy));
};
X509._oids = {
  // 1.2.840.10045.3.1.7 prime256v1
  // (ANSI X9.62 named elliptic curve) (06 08 - 2A 86 48 CE 3D 03 01 07)
  'P-256': '2a8648ce3d030107'
  // 1.3.132.0.34 P-384 (06 05 - 2B 81 04 00 22)
  // (SEC 2 recommended EC domain secp256r1)
, 'P-384': '2b81040022'
  // requires more logic and isn't a recommended standard
  // 1.3.132.0.35 P-521 (06 05 - 2B 81 04 00 23)
  // (SEC 2 alternate P-521)
//, 'P-521': '2B 81 04 00 23'
};

// don't replace the full parseBlock, if it exists
PEM.parseBlock = PEM.parseBlock || function (str) {
  var der = str.split(/\n/).filter(function (line) {
    return !/-----/.test(line);
  }).join('');
  return { bytes: Enc.base64ToBuf(der) };
};

}('undefined' === typeof window ? module.exports : window));