forked from nodejs/node
-
Notifications
You must be signed in to change notification settings - Fork 0
/
sri.js
73 lines (66 loc) · 2.03 KB
/
sri.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
'use strict';
// Utility to parse the value of
// https://w3c.github.io/webappsec-subresource-integrity/#the-integrity-attribute
const {
ArrayPrototype,
ObjectDefineProperty,
ObjectFreeze,
ObjectSeal,
ObjectSetPrototypeOf,
RegExp,
RegExpPrototypeExec,
StringPrototypeSlice,
} = primordials;
const {
ERR_SRI_PARSE,
} = require('internal/errors').codes;
const kWSP = '[\\x20\\x09]';
const kVCHAR = '[\\x21-\\x7E]';
const kHASH_ALGO = 'sha(?:256|384|512)';
// Base64
const kHASH_VALUE = '[A-Za-z0-9+/]+[=]{0,2}';
const kHASH_EXPRESSION = `(${kHASH_ALGO})-(${kHASH_VALUE})`;
// Ungrouped since unused
const kOPTION_EXPRESSION = `(?:${kVCHAR}*)`;
const kHASH_WITH_OPTIONS = `${kHASH_EXPRESSION}(?:[?](${kOPTION_EXPRESSION}))?`;
const kSRIPattern = RegExp(`(${kWSP}*)(?:${kHASH_WITH_OPTIONS})`, 'g');
ObjectSeal(kSRIPattern);
const kAllWSP = RegExp(`^${kWSP}*$`);
ObjectSeal(kAllWSP);
const BufferFrom = require('buffer').Buffer.from;
// Returns {algorithm, value (in base64 string), options,}[]
const parse = (str) => {
let prevIndex = 0;
let match;
const entries = [];
while ((match = RegExpPrototypeExec(kSRIPattern, str)) !== null) {
if (match.index !== prevIndex) {
throw new ERR_SRI_PARSE(str, str[prevIndex], prevIndex);
}
if (entries.length > 0 && match[1] === '') {
throw new ERR_SRI_PARSE(str, str[prevIndex], prevIndex);
}
// Avoid setters being fired
ObjectDefineProperty(entries, entries.length, {
__proto__: null,
enumerable: true,
configurable: true,
value: ObjectFreeze({
__proto__: null,
algorithm: match[2],
value: BufferFrom(match[3], 'base64'),
options: match[4] === undefined ? null : match[4],
}),
});
prevIndex += match[0].length;
}
if (prevIndex !== str.length) {
if (RegExpPrototypeExec(kAllWSP, StringPrototypeSlice(str, prevIndex)) === null) {
throw new ERR_SRI_PARSE(str, str[prevIndex], prevIndex);
}
}
return ObjectSetPrototypeOf(entries, ArrayPrototype);
};
module.exports = {
parse,
};