old-keypairs.js/keypairs.js

345 lines
11 KiB
JavaScript

'use strict';
var Eckles = require('eckles');
var Rasha = require('rasha');
var Enc = {};
var Keypairs = module.exports;
/*global Promise*/
Keypairs.generate = function (opts) {
opts = opts || {};
var kty = opts.kty || opts.type;
var p;
if ('RSA' === kty) {
p = Rasha.generate(opts);
} else {
p = Eckles.generate(opts);
}
return p.then(function (pair) {
return Keypairs.thumbprint({ jwk: pair.public }).then(function (thumb) {
pair.private.kid = thumb; // maybe not the same id on the private key?
pair.public.kid = thumb;
return pair;
});
});
};
Keypairs.parse = function (opts) {
opts = opts || {};
var err;
var jwk;
var pem;
var p;
if (!opts.key || !opts.key.kty) {
try {
jwk = JSON.parse(opts.key);
p = Keypairs.export({ jwk: jwk }).catch(function (e) {
pem = opts.key;
err = new Error("Not a valid jwk '" + JSON.stringify(jwk) + "':" + e.message);
err.code = "EINVALID";
return Promise.reject(err);
}).then(function () {
return jwk;
});
} catch(e) {
p = Keypairs.import({ pem: opts.key }).catch(function (e) {
err = new Error("Could not parse key (type " + typeof opts.key + ") '" + opts.key + "': " + e.message);
err.code = "EPARSE";
return Promise.reject(err);
});
}
} else {
p = Promise.resolve(opts.key);
}
return p.then(function (jwk) {
var pubopts = JSON.parse(JSON.stringify(opts));
pubopts.jwk = jwk;
return Keypairs.publish(pubopts).then(function (pub) {
// 'd' happens to be the name of a private part of both RSA and ECDSA keys
if (opts.public || opts.publish || !jwk.d) {
if (opts.private) {
// TODO test that it can actually sign?
err = new Error("Not a private key '" + JSON.stringify(jwk) + "'");
err.code = "ENOTPRIVATE";
return Promise.reject(err);
}
return { public: pub };
} else {
return { private: jwk, public: pub };
}
});
});
};
Keypairs.parseOrGenerate = function (opts) {
if (!opts.key) { return Keypairs.generate(opts); }
opts.private = true;
return Keypairs.parse(opts).catch(function (e) {
console.warn(e.message);
return Keypairs.generate(opts);
});
};
Keypairs.import = function (opts) {
return Eckles.import(opts).catch(function () {
return Rasha.import(opts);
}).then(function (jwk) {
return Keypairs.thumbprint({ jwk: jwk }).then(function (thumb) {
jwk.kid = thumb;
return jwk;
});
});
};
Keypairs.export = function (opts) {
return Promise.resolve().then(function () {
if ('RSA' === opts.jwk.kty) {
return Rasha.export(opts);
} else {
return Eckles.export(opts);
}
});
};
// Chopping off the private parts is now part of the public API.
// I thought it sounded a little too crude at first, but it really is the best name in every possible way.
Keypairs.neuter = Keypairs._neuter = function (opts) {
// trying to find the best balance of an immutable copy with custom attributes
var jwk = {};
Object.keys(opts.jwk).forEach(function (k) {
if ('undefined' === typeof opts.jwk[k]) { return; }
// ignore RSA and EC private parts
if (-1 !== ['d', 'p', 'q', 'dp', 'dq', 'qi'].indexOf(k)) { return; }
jwk[k] = JSON.parse(JSON.stringify(opts.jwk[k]));
});
return jwk;
};
Keypairs.publish = function (opts) {
if ('object' !== typeof opts.jwk || !opts.jwk.kty) { throw new Error("invalid jwk: " + JSON.stringify(opts.jwk)); }
// returns a copy
var jwk = Keypairs.neuter(opts);
if (jwk.exp) {
jwk.exp = setTime(jwk.exp);
} else {
if (opts.exp) { jwk.exp = setTime(opts.exp); }
else if (opts.expiresIn) { jwk.exp = Math.round(Date.now()/1000) + opts.expiresIn; }
else if (opts.expiresAt) { jwk.exp = opts.expiresAt; }
}
if (!jwk.use && false !== jwk.use) { jwk.use = "sig"; }
if (jwk.kid) { return Promise.resolve(jwk); }
return Keypairs.thumbprint({ jwk: jwk }).then(function (thumb) { jwk.kid = thumb; return jwk; });
};
Keypairs.thumbprint = function (opts) {
return Promise.resolve().then(function () {
if ('RSA' === opts.jwk.kty) {
return Rasha.thumbprint(opts);
} else {
return Eckles.thumbprint(opts);
}
});
};
// JWT a.k.a. JWS with Claims using Compact Serialization
Keypairs.signJwt = function (opts) {
return Keypairs.thumbprint({ jwk: opts.jwk }).then(function (thumb) {
var header = opts.header || {};
var claims = JSON.parse(JSON.stringify(opts.claims || {}));
header.typ = 'JWT';
if (!header.kid) { header.kid = thumb; }
if (!header.alg && opts.alg) { header.alg = opts.alg; }
if (!claims.iat && (false === claims.iat || false === opts.iat)) {
claims.iat = undefined;
} else if (!claims.iat) {
claims.iat = Math.round(Date.now()/1000);
}
if (opts.exp) {
claims.exp = setTime(opts.exp);
} else if (!claims.exp && (false === claims.exp || false === opts.exp)) {
claims.exp = undefined;
} else if (!claims.exp) {
throw new Error("opts.claims.exp should be the expiration date as seconds, human form (i.e. '1h' or '15m') or false");
}
if (opts.iss) { claims.iss = opts.iss; }
if (!claims.iss && (false === claims.iss || false === opts.iss)) {
claims.iss = undefined;
} else if (!claims.iss) {
throw new Error("opts.claims.iss should be in the form of https://example.com/, a secure OIDC base url");
}
return Keypairs.signJws({
jwk: opts.jwk
, pem: opts.pem
, protected: header
, header: undefined
, payload: claims
}).then(function (jws) {
return [ jws.protected, jws.payload, jws.signature ].join('.');
});
});
};
Keypairs.signJws = function (opts) {
return Keypairs.thumbprint(opts).then(function (thumb) {
function alg() {
if (!opts.jwk) {
throw new Error("opts.jwk must exist and must declare 'typ'");
}
return ('RSA' === opts.jwk.kty) ? "RS256" : "ES256";
}
function sign(pem) {
var header = opts.header;
var protect = opts.protected;
var payload = opts.payload;
// Compute JWS signature
var protectedHeader = "";
// Because unprotected headers are allowed, regrettably...
// https://stackoverflow.com/a/46288694
if (false !== protect) {
if (!protect) { protect = {}; }
if (!protect.alg) { protect.alg = alg(); }
// There's a particular request where Let's Encrypt explicitly doesn't use a kid
if (!protect.kid && false !== protect.kid) { protect.kid = thumb; }
protectedHeader = JSON.stringify(protect);
}
// Convert payload to Buffer
if ('string' !== typeof payload && !Buffer.isBuffer(payload)) {
if (!payload) {
throw new Error("opts.payload should be JSON, string, or Buffer (it may be empty, but that must be explicit)");
}
payload = JSON.stringify(payload);
}
if ('string' === typeof payload) {
payload = Buffer.from(payload, 'binary');
}
// node specifies RSA-SHAxxx even whet it's actually ecdsa (it's all encoded x509 shasums anyway)
var nodeAlg = "SHA" + (((protect||header).alg||'').replace(/^[^\d]+/, '')||'256');
var protected64 = Enc.strToUrlBase64(protectedHeader);
var payload64 = Enc.bufToUrlBase64(payload);
var binsig = require('crypto')
.createSign(nodeAlg)
.update(protect ? (protected64 + "." + payload64) : payload64)
.sign(pem)
;
if ('EC' === opts.jwk.kty) {
// ECDSA JWT signatures differ from "normal" ECDSA signatures
// https://tools.ietf.org/html/rfc7518#section-3.4
binsig = convertIfEcdsa(binsig);
}
var sig = binsig.toString('base64')
.replace(/\+/g, '-')
.replace(/\//g, '_')
.replace(/=/g, '')
;
return {
header: header
, protected: protected64 || undefined
, payload: payload64
, signature: sig
};
}
function convertIfEcdsa(binsig) {
// should have asn1 sequence header of 0x30
if (0x30 !== binsig[0]) { throw new Error("Impossible EC SHA head marker"); }
var index = 2; // first ecdsa "R" header byte
var len = binsig[1];
var lenlen = 0;
// Seek length of length if length is greater than 127 (i.e. two 512-bit / 64-byte R and S values)
if (0x80 & len) {
lenlen = len - 0x80; // should be exactly 1
len = binsig[2]; // should be <= 130 (two 64-bit SHA-512s, plus padding)
index += lenlen;
}
// should be of BigInt type
if (0x02 !== binsig[index]) { throw new Error("Impossible EC SHA R marker"); }
index += 1;
var rlen = binsig[index];
var bits = 32;
if (rlen > 49) {
bits = 64;
} else if (rlen > 33) {
bits = 48;
}
var r = binsig.slice(index + 1, index + 1 + rlen).toString('hex');
var slen = binsig[index + 1 + rlen + 1]; // skip header and read length
var s = binsig.slice(index + 1 + rlen + 1 + 1).toString('hex');
if (2 *slen !== s.length) { throw new Error("Impossible EC SHA S length"); }
// There may be one byte of padding on either
while (r.length < 2*bits) { r = '00' + r; }
while (s.length < 2*bits) { s = '00' + s; }
if (2*(bits+1) === r.length) { r = r.slice(2); }
if (2*(bits+1) === s.length) { s = s.slice(2); }
return Buffer.concat([Buffer.from(r, 'hex'), Buffer.from(s, 'hex')]);
}
if (opts.pem && opts.jwk) {
return sign(opts.pem);
} else {
return Keypairs.export({ jwk: opts.jwk }).then(sign);
}
});
};
function setTime(time) {
if ('number' === typeof time) { return time; }
var t = time.match(/^(\-?\d+)([dhms])$/i);
if (!t || !t[0]) {
throw new Error("'" + time + "' should be datetime in seconds or human-readable format (i.e. 3d, 1h, 15m, 30s");
}
var now = Math.round(Date.now()/1000);
var num = parseInt(t[1], 10);
var unit = t[2];
var mult = 1;
switch(unit) {
// fancy fallthrough, what fun!
case 'd':
mult *= 24;
/*falls through*/
case 'h':
mult *= 60;
/*falls through*/
case 'm':
mult *= 60;
/*falls through*/
case 's':
mult *= 1;
}
return now + (mult * num);
}
Enc.strToUrlBase64 = function (str) {
// node automatically can tell the difference
// between uc2 (utf-8) strings and binary strings
// so we don't have to re-encode the strings
return Buffer.from(str).toString('base64')
.replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '');
};
Enc.bufToUrlBase64 = function (buf) {
// allow for Uint8Array as a Buffer
return Buffer.from(buf).toString('base64')
.replace(/\+/g, '-').replace(/\//g, '_').replace(/=/g, '');
};