acme.js/lib/keypairs.js

433 lines
11 KiB
JavaScript

/*global Promise*/
(function(exports) {
'use strict';
var Keypairs = (exports.Keypairs = {});
var Rasha = exports.Rasha;
var Eckles = exports.Eckles;
var Enc = exports.Enc || {};
Keypairs._stance =
"We take the stance that if you're knowledgeable enough to" +
" properly and securely use non-standard crypto then you shouldn't need Bluecrypt anyway.";
Keypairs._universal =
'Bluecrypt only supports crypto with standard cross-browser and cross-platform support.';
Keypairs.generate = function(opts) {
opts = opts || {};
var p;
if (!opts.kty) {
opts.kty = opts.type;
}
if (!opts.kty) {
opts.kty = 'EC';
}
if (/^EC/i.test(opts.kty)) {
p = Eckles.generate(opts);
} else if (/^RSA$/i.test(opts.kty)) {
p = Rasha.generate(opts);
} else {
return Promise.Reject(
new Error(
"'" +
opts.kty +
"' is not a well-supported key type." +
Keypairs._universal +
" Please choose 'EC', or 'RSA' if you have good reason to."
)
);
}
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.export = function(opts) {
return Eckles.export(opts).catch(function(err) {
return Rasha.export(opts).catch(function() {
return Promise.reject(err);
});
});
};
/**
* 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 = 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.thumbprint = function(opts) {
return Promise.resolve().then(function() {
if (/EC/i.test(opts.jwk.kty)) {
return Eckles.thumbprint(opts);
} else {
return Rasha.thumbprint(opts);
}
});
};
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;
});
};
// 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'"
);
}
if (opts.jwk.alg) {
return opts.jwk.alg;
}
var typ = 'RSA' === opts.jwk.kty ? 'RS' : 'ES';
return typ + Keypairs._getBits(opts);
}
function sign() {
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 ACME / Let's Encrypt explicitly doesn't use a kid
if (false === protect.kid) {
protect.kid = undefined;
} else if (!protect.kid) {
protect.kid = thumb;
}
protectedHeader = JSON.stringify(protect);
}
// Not sure how to handle the empty case since ACME POST-as-GET must be empty
//if (!payload) {
// throw new Error("opts.payload should be JSON, string, or ArrayBuffer (it may be empty, but that must be explicit)");
//}
// Trying to detect if it's a plain object (not Buffer, ArrayBuffer, Array, Uint8Array, etc)
if (
payload &&
'string' !== typeof payload &&
'undefined' === typeof payload.byteLength &&
'undefined' === typeof payload.buffer
) {
payload = JSON.stringify(payload);
}
// Converting to a buffer, even if it was just converted to a string
if ('string' === typeof payload) {
payload = Enc.binToBuf(payload);
}
// node specifies RSA-SHAxxx even when it's actually ecdsa (it's all encoded x509 shasums anyway)
var protected64 = Enc.strToUrlBase64(protectedHeader);
var payload64 = Enc.bufToUrlBase64(payload);
var msg = protected64 + '.' + payload64;
return Keypairs._sign(opts, msg).then(function(buf) {
var signedMsg = {
protected: protected64,
payload: payload64,
signature: Enc.bufToUrlBase64(buf)
};
return signedMsg;
});
}
if (opts.jwk) {
return sign();
} else {
return Keypairs.import({ pem: opts.pem }).then(function(pair) {
opts.jwk = pair.private;
return sign();
});
}
});
};
Keypairs._sign = function(opts, payload) {
return Keypairs._import(opts).then(function(privkey) {
if ('string' === typeof payload) {
payload = new TextEncoder().encode(payload);
}
return window.crypto.subtle
.sign(
{
name: Keypairs._getName(opts),
hash: { name: 'SHA-' + Keypairs._getBits(opts) }
},
privkey,
payload
)
.then(function(signature) {
signature = new Uint8Array(signature); // ArrayBuffer -> u8
// This will come back into play for CSRs, but not for JOSE
if (
'EC' === opts.jwk.kty &&
/x509|asn1/i.test(opts.format)
) {
return Keypairs._ecdsaJoseSigToAsn1Sig(signature);
} else {
// jose/jws/jwt
return signature;
}
});
});
};
Keypairs._getBits = function(opts) {
if (opts.alg) {
return opts.alg.replace(/[a-z\-]/gi, '');
}
// base64 len to byte len
var len = Math.floor((opts.jwk.n || '').length * 0.75);
// TODO this may be a bug
// need to confirm that the padding is no more or less than 1 byte
if (/521/.test(opts.jwk.crv) || len >= 511) {
return '512';
} else if (/384/.test(opts.jwk.crv) || len >= 383) {
return '384';
}
return '256';
};
Keypairs._getName = function(opts) {
if (/EC/i.test(opts.jwk.kty)) {
return 'ECDSA';
} else {
return 'RSASSA-PKCS1-v1_5';
}
};
Keypairs._import = function(opts) {
return Promise.resolve().then(function() {
var ops;
// all private keys just happen to have a 'd'
if (opts.jwk.d) {
ops = ['sign'];
} else {
ops = ['verify'];
}
// gotta mark it as extractable, as if it matters
opts.jwk.ext = true;
opts.jwk.key_ops = ops;
return window.crypto.subtle
.importKey(
'jwk',
opts.jwk,
{
name: Keypairs._getName(opts),
namedCurve: opts.jwk.crv,
hash: { name: 'SHA-' + Keypairs._getBits(opts) }
},
true,
ops
)
.then(function(privkey) {
delete opts.jwk.ext;
return privkey;
});
});
};
// ECDSA JOSE / JWS / JWT signatures differ from "normal" ASN1/X509 ECDSA signatures
// https://tools.ietf.org/html/rfc7518#section-3.4
Keypairs._ecdsaJoseSigToAsn1Sig = function(bufsig) {
// it's easier to do the manipulation in the browser with an array
bufsig = Array.from(bufsig);
var hlen = bufsig.length / 2; // should be even
var r = bufsig.slice(0, hlen);
var s = bufsig.slice(hlen);
// unpad positive ints less than 32 bytes wide
while (!r[0]) {
r = r.slice(1);
}
while (!s[0]) {
s = s.slice(1);
}
// pad (or re-pad) ambiguously non-negative BigInts, up to 33 bytes wide
if (0x80 & r[0]) {
r.unshift(0);
}
if (0x80 & s[0]) {
s.unshift(0);
}
var len = 2 + r.length + 2 + s.length;
var head = [0x30];
// hard code 0x80 + 1 because it won't be longer than
// two SHA512 plus two pad bytes (130 bytes <= 256)
if (len >= 0x80) {
head.push(0x81);
}
head.push(len);
return Uint8Array.from(
head.concat([0x02, r.length], r, [0x02, s.length], s)
);
};
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.hexToBuf = function(hex) {
var arr = [];
hex.match(/.{2}/g).forEach(function(h) {
arr.push(parseInt(h, 16));
});
return 'undefined' !== typeof Uint8Array ? new Uint8Array(arr) : arr;
};
Enc.strToUrlBase64 = function(str) {
return Enc.bufToUrlBase64(Enc.binToBuf(str));
};
Enc.binToBuf = function(bin) {
var arr = bin.split('').map(function(ch) {
return ch.charCodeAt(0);
});
return 'undefined' !== typeof Uint8Array ? new Uint8Array(arr) : arr;
};
})('undefined' !== typeof module ? module.exports : window);