-
Notifications
You must be signed in to change notification settings - Fork 24
/
sign.js
284 lines (255 loc) · 8.96 KB
/
sign.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
/* jshint esversion: 6 */
/* jslint node: true */
'use strict';
const cbor = require('cbor');
const EC = require('elliptic').ec;
const crypto = require('crypto');
const NodeRSA = require('node-rsa');
const common = require('./common');
const EMPTY_BUFFER = common.EMPTY_BUFFER;
const Tagged = cbor.Tagged;
const SignTag = exports.SignTag = 98;
const Sign1Tag = exports.Sign1Tag = 18;
const AlgFromTags = {};
AlgFromTags[-7] = { sign: 'ES256', digest: 'SHA-256' };
AlgFromTags[-35] = { sign: 'ES384', digest: 'SHA-384' };
AlgFromTags[-36] = { sign: 'ES512', digest: 'SHA-512' };
AlgFromTags[-37] = { sign: 'PS256', digest: 'SHA-256' };
AlgFromTags[-38] = { sign: 'PS384', digest: 'SHA-384' };
AlgFromTags[-39] = { sign: 'PS512', digest: 'SHA-512' };
AlgFromTags[-257] = { sign: 'RS256', digest: 'SHA-256' };
AlgFromTags[-258] = { sign: 'RS384', digest: 'SHA-384' };
AlgFromTags[-259] = { sign: 'RS512', digest: 'SHA-512' };
const COSEAlgToNodeAlg = {
ES256: { sign: 'p256', digest: 'sha256' },
ES384: { sign: 'p384', digest: 'sha384' },
ES512: { sign: 'p521', digest: 'sha512' },
RS256: { sign: 'RSA-SHA256' },
RS384: { sign: 'RSA-SHA384' },
RS512: { sign: 'RSA-SHA512' },
PS256: { alg: 'pss-sha256', saltLen: 32 },
PS384: { alg: 'pss-sha384', saltLen: 48 },
PS512: { alg: 'pss-sha512', saltLen: 64 }
};
function doSign (SigStructure, signer, alg) {
if (!AlgFromTags[alg]) {
throw new Error('Unknown algorithm, ' + alg);
}
if (!COSEAlgToNodeAlg[AlgFromTags[alg].sign]) {
throw new Error('Unsupported algorithm, ' + AlgFromTags[alg].sign);
}
let ToBeSigned = cbor.encode(SigStructure);
let sig;
if (AlgFromTags[alg].sign.startsWith('ES')) {
const hash = crypto.createHash(COSEAlgToNodeAlg[AlgFromTags[alg].sign].digest);
hash.update(ToBeSigned);
ToBeSigned = hash.digest();
const ec = new EC(COSEAlgToNodeAlg[AlgFromTags[alg].sign].sign);
const key = ec.keyFromPrivate(signer.key.d);
const signature = key.sign(ToBeSigned);
const bitLength = Math.ceil(ec.curve._bitLength / 8);
sig = Buffer.concat([signature.r.toArrayLike(Buffer, undefined, bitLength), signature.s.toArrayLike(Buffer, undefined, bitLength)]);
} else if (AlgFromTags[alg].sign.startsWith('PS')) {
signer.key.dmp1 = signer.key.dp;
signer.key.dmq1 = signer.key.dq;
signer.key.coeff = signer.key.qi;
const key = new NodeRSA().importKey(signer.key, 'components-private');
key.setOptions({
signingScheme: {
scheme: COSEAlgToNodeAlg[AlgFromTags[alg].sign].alg.split('-')[0],
hash: COSEAlgToNodeAlg[AlgFromTags[alg].sign].alg.split('-')[1],
saltLength: COSEAlgToNodeAlg[AlgFromTags[alg].sign].saltLen
}
});
sig = key.sign(ToBeSigned);
} else {
const sign = crypto.createSign(COSEAlgToNodeAlg[AlgFromTags[alg].sign].sign);
sign.update(ToBeSigned);
sign.end();
sig = sign.sign(signer.key);
}
return sig;
}
exports.create = function (headers, payload, signers, options) {
options = options || {};
let u = headers.u || {};
let p = headers.p || {};
p = common.TranslateHeaders(p);
u = common.TranslateHeaders(u);
let bodyP = p || {};
bodyP = (bodyP.size === 0) ? EMPTY_BUFFER : cbor.encode(bodyP);
if (Array.isArray(signers)) {
if (signers.length === 0) {
throw new Error('There has to be at least one signer');
}
if (signers.length > 1) {
throw new Error('Only one signer is supported');
}
// TODO handle multiple signers
const signer = signers[0];
const externalAAD = signer.externalAAD || EMPTY_BUFFER;
let signerP = signer.p || {};
let signerU = signer.u || {};
signerP = common.TranslateHeaders(signerP);
signerU = common.TranslateHeaders(signerU);
const alg = signerP.get(common.HeaderParameters.alg);
signerP = (signerP.size === 0) ? EMPTY_BUFFER : cbor.encode(signerP);
const SigStructure = [
'Signature',
bodyP,
signerP,
externalAAD,
payload
];
const sig = doSign(SigStructure, signer, alg);
if (p.size === 0 && options.encodep === 'empty') {
p = EMPTY_BUFFER;
} else {
p = cbor.encode(p);
}
const signed = [p, u, payload, [[signerP, signerU, sig]]];
return cbor.encodeAsync(options.excludetag ? signed : new Tagged(SignTag, signed));
} else {
const signer = signers;
const externalAAD = signer.externalAAD || EMPTY_BUFFER;
const alg = p.get(common.HeaderParameters.alg) || u.get(common.HeaderParameters.alg);
const SigStructure = [
'Signature1',
bodyP,
externalAAD,
payload
];
const sig = doSign(SigStructure, signer, alg);
if (p.size === 0 && options.encodep === 'empty') {
p = EMPTY_BUFFER;
} else {
p = cbor.encode(p);
}
const signed = [p, u, payload, sig];
return cbor.encodeAsync(options.excludetag ? signed : new Tagged(Sign1Tag, signed), { canonical: true });
}
};
function doVerify (SigStructure, verifier, alg, sig) {
if (!AlgFromTags[alg]) {
throw new Error('Unknown algorithm, ' + alg);
}
const nodeAlg = COSEAlgToNodeAlg[AlgFromTags[alg].sign];
if (!nodeAlg) {
throw new Error('Unsupported algorithm, ' + AlgFromTags[alg].sign);
}
const ToBeSigned = cbor.encode(SigStructure);
if (AlgFromTags[alg].sign.startsWith('ES')) {
const hash = crypto.createHash(nodeAlg.digest);
hash.update(ToBeSigned);
const msgHash = hash.digest();
const pub = { x: verifier.key.x, y: verifier.key.y };
const ec = new EC(nodeAlg.sign);
const key = ec.keyFromPublic(pub);
sig = { r: sig.slice(0, sig.length / 2), s: sig.slice(sig.length / 2) };
if (!key.verify(msgHash, sig)) {
throw new Error('Signature missmatch');
}
} else if (AlgFromTags[alg].sign.startsWith('PS')) {
const key = new NodeRSA().importKey(verifier.key, 'components-public');
key.setOptions({
signingScheme: {
scheme: COSEAlgToNodeAlg[AlgFromTags[alg].sign].alg.split('-')[0],
hash: COSEAlgToNodeAlg[AlgFromTags[alg].sign].alg.split('-')[1],
saltLength: COSEAlgToNodeAlg[AlgFromTags[alg].sign].saltLen
}
});
if (!key.verify(ToBeSigned, sig, 'buffer', 'buffer')) {
throw new Error('Signature missmatch');
}
} else {
const verify = crypto.createVerify(nodeAlg.sign);
verify.update(ToBeSigned);
if (!verify.verify(verifier.key, sig)) {
throw new Error('Signature missmatch');
}
}
}
function getSigner (signers, verifier) {
for (let i = 0; i < signers.length; i++) {
const kid = signers[i][1].get(common.HeaderParameters.kid); // TODO create constant for header locations
if (kid.equals(Buffer.from(verifier.key.kid, 'utf8'))) {
return signers[i];
}
}
}
function getCommonParameter (first, second, parameter) {
let result;
if (first.get) {
result = first.get(parameter);
}
if (!result && second.get) {
result = second.get(parameter);
}
return result;
}
exports.verify = async function (payload, verifier, options) {
options = options || {};
const obj = await cbor.decodeFirst(payload);
return verifyInternal(verifier, options, obj);
};
exports.verifySync = function (payload, verifier, options) {
options = options || {};
const obj = cbor.decodeFirstSync(payload);
return verifyInternal(verifier, options, obj);
};
function verifyInternal (verifier, options, obj) {
options = options || {};
let type = options.defaultType ? options.defaultType : SignTag;
if (obj instanceof Tagged) {
if (obj.tag !== SignTag && obj.tag !== Sign1Tag) {
throw new Error('Unexpected cbor tag, \'' + obj.tag + '\'');
}
type = obj.tag;
obj = obj.value;
}
if (!Array.isArray(obj)) {
throw new Error('Expecting Array');
}
if (obj.length !== 4) {
throw new Error('Expecting Array of lenght 4');
}
let [p, u, plaintext, signers] = obj;
if (type === SignTag && !Array.isArray(signers)) {
throw new Error('Expecting signature Array');
}
p = (!p.length) ? EMPTY_BUFFER : cbor.decodeFirstSync(p);
u = (!u.size) ? EMPTY_BUFFER : u;
const signer = (type === SignTag ? getSigner(signers, verifier) : signers);
if (!signer) {
throw new Error('Failed to find signer with kid' + verifier.key.kid);
}
if (type === SignTag) {
const externalAAD = verifier.externalAAD || EMPTY_BUFFER;
let [signerP, , sig] = signer;
signerP = (!signerP.length) ? EMPTY_BUFFER : signerP;
p = (!p.size) ? EMPTY_BUFFER : cbor.encode(p);
const signerPMap = cbor.decode(signerP);
const alg = signerPMap.get(common.HeaderParameters.alg);
const SigStructure = [
'Signature',
p,
signerP,
externalAAD,
plaintext
];
doVerify(SigStructure, verifier, alg, sig);
return plaintext;
} else {
const externalAAD = verifier.externalAAD || EMPTY_BUFFER;
const alg = getCommonParameter(p, u, common.HeaderParameters.alg);
p = (!p.size) ? EMPTY_BUFFER : cbor.encode(p);
const SigStructure = [
'Signature1',
p,
externalAAD,
plaintext
];
doVerify(SigStructure, verifier, alg, signer);
return plaintext;
}
}