455 lines
13 KiB
JavaScript
455 lines
13 KiB
JavaScript
'use strict'
|
|
|
|
const crypto = require('crypto')
|
|
const figgyPudding = require('figgy-pudding')
|
|
const MiniPass = require('minipass')
|
|
|
|
const SPEC_ALGORITHMS = ['sha256', 'sha384', 'sha512']
|
|
|
|
const BASE64_REGEX = /^[a-z0-9+/]+(?:=?=?)$/i
|
|
const SRI_REGEX = /^([^-]+)-([^?]+)([?\S*]*)$/
|
|
const STRICT_SRI_REGEX = /^([^-]+)-([A-Za-z0-9+/=]{44,88})(\?[\x21-\x7E]*)?$/
|
|
const VCHAR_REGEX = /^[\x21-\x7E]+$/
|
|
|
|
const SsriOpts = figgyPudding({
|
|
algorithms: { default: ['sha512'] },
|
|
error: { default: false },
|
|
integrity: {},
|
|
options: { default: [] },
|
|
pickAlgorithm: { default: () => getPrioritizedHash },
|
|
sep: { default: ' ' },
|
|
single: { default: false },
|
|
size: {},
|
|
strict: { default: false }
|
|
})
|
|
|
|
const getOptString = options => !options || !options.length ? ''
|
|
: `?${options.join('?')}`
|
|
|
|
const _onEnd = Symbol('_onEnd')
|
|
const _getOptions = Symbol('_getOptions')
|
|
class IntegrityStream extends MiniPass {
|
|
constructor (opts) {
|
|
super()
|
|
this.size = 0
|
|
this.opts = opts
|
|
|
|
// may be overridden later, but set now for class consistency
|
|
this[_getOptions]()
|
|
|
|
// options used for calculating stream. can't be changed.
|
|
this.algorithms = Array.from(
|
|
new Set(opts.algorithms.concat(this.algorithm ? [this.algorithm] : []))
|
|
)
|
|
this.hashes = this.algorithms.map(crypto.createHash)
|
|
}
|
|
|
|
[_getOptions] () {
|
|
const opts = this.opts
|
|
// For verification
|
|
this.sri = opts.integrity ? parse(opts.integrity, opts) : null
|
|
this.expectedSize = opts.size
|
|
this.goodSri = this.sri ? !!Object.keys(this.sri).length : false
|
|
this.algorithm = this.goodSri ? this.sri.pickAlgorithm(opts) : null
|
|
this.digests = this.goodSri ? this.sri[this.algorithm] : null
|
|
this.optString = getOptString(opts.options)
|
|
}
|
|
|
|
emit (ev, data) {
|
|
if (ev === 'end') this[_onEnd]()
|
|
return super.emit(ev, data)
|
|
}
|
|
|
|
write (data) {
|
|
this.size += data.length
|
|
this.hashes.forEach(h => h.update(data))
|
|
return super.write(data)
|
|
}
|
|
|
|
[_onEnd] () {
|
|
if (!this.goodSri) {
|
|
this[_getOptions]()
|
|
}
|
|
const newSri = parse(this.hashes.map((h, i) => {
|
|
return `${this.algorithms[i]}-${h.digest('base64')}${this.optString}`
|
|
}).join(' '), this.opts)
|
|
// Integrity verification mode
|
|
const match = this.goodSri && newSri.match(this.sri, this.opts)
|
|
if (typeof this.expectedSize === 'number' && this.size !== this.expectedSize) {
|
|
const err = new Error(`stream size mismatch when checking ${this.sri}.\n Wanted: ${this.expectedSize}\n Found: ${this.size}`)
|
|
err.code = 'EBADSIZE'
|
|
err.found = this.size
|
|
err.expected = this.expectedSize
|
|
err.sri = this.sri
|
|
this.emit('error', err)
|
|
} else if (this.sri && !match) {
|
|
const err = new Error(`${this.sri} integrity checksum failed when using ${this.algorithm}: wanted ${this.digests} but got ${newSri}. (${this.size} bytes)`)
|
|
err.code = 'EINTEGRITY'
|
|
err.found = newSri
|
|
err.expected = this.digests
|
|
err.algorithm = this.algorithm
|
|
err.sri = this.sri
|
|
this.emit('error', err)
|
|
} else {
|
|
this.emit('size', this.size)
|
|
this.emit('integrity', newSri)
|
|
match && this.emit('verified', match)
|
|
}
|
|
}
|
|
}
|
|
|
|
class Hash {
|
|
get isHash () { return true }
|
|
constructor (hash, opts) {
|
|
opts = SsriOpts(opts)
|
|
const strict = !!opts.strict
|
|
this.source = hash.trim()
|
|
|
|
// set default values so that we make V8 happy to
|
|
// always see a familiar object template.
|
|
this.digest = ''
|
|
this.algorithm = ''
|
|
this.options = []
|
|
|
|
// 3.1. Integrity metadata (called "Hash" by ssri)
|
|
// https://w3c.github.io/webappsec-subresource-integrity/#integrity-metadata-description
|
|
const match = this.source.match(
|
|
strict
|
|
? STRICT_SRI_REGEX
|
|
: SRI_REGEX
|
|
)
|
|
if (!match) { return }
|
|
if (strict && !SPEC_ALGORITHMS.some(a => a === match[1])) { return }
|
|
this.algorithm = match[1]
|
|
this.digest = match[2]
|
|
|
|
const rawOpts = match[3]
|
|
if (rawOpts) {
|
|
this.options = rawOpts.slice(1).split('?')
|
|
}
|
|
}
|
|
|
|
hexDigest () {
|
|
return this.digest && Buffer.from(this.digest, 'base64').toString('hex')
|
|
}
|
|
|
|
toJSON () {
|
|
return this.toString()
|
|
}
|
|
|
|
toString (opts) {
|
|
opts = SsriOpts(opts)
|
|
if (opts.strict) {
|
|
// Strict mode enforces the standard as close to the foot of the
|
|
// letter as it can.
|
|
if (!(
|
|
// The spec has very restricted productions for algorithms.
|
|
// https://www.w3.org/TR/CSP2/#source-list-syntax
|
|
SPEC_ALGORITHMS.some(x => x === this.algorithm) &&
|
|
// Usually, if someone insists on using a "different" base64, we
|
|
// leave it as-is, since there's multiple standards, and the
|
|
// specified is not a URL-safe variant.
|
|
// https://www.w3.org/TR/CSP2/#base64_value
|
|
this.digest.match(BASE64_REGEX) &&
|
|
// Option syntax is strictly visual chars.
|
|
// https://w3c.github.io/webappsec-subresource-integrity/#grammardef-option-expression
|
|
// https://tools.ietf.org/html/rfc5234#appendix-B.1
|
|
this.options.every(opt => opt.match(VCHAR_REGEX))
|
|
)) {
|
|
return ''
|
|
}
|
|
}
|
|
const options = this.options && this.options.length
|
|
? `?${this.options.join('?')}`
|
|
: ''
|
|
return `${this.algorithm}-${this.digest}${options}`
|
|
}
|
|
}
|
|
|
|
class Integrity {
|
|
get isIntegrity () { return true }
|
|
toJSON () {
|
|
return this.toString()
|
|
}
|
|
|
|
toString (opts) {
|
|
opts = SsriOpts(opts)
|
|
let sep = opts.sep || ' '
|
|
if (opts.strict) {
|
|
// Entries must be separated by whitespace, according to spec.
|
|
sep = sep.replace(/\S+/g, ' ')
|
|
}
|
|
return Object.keys(this).map(k => {
|
|
return this[k].map(hash => {
|
|
return Hash.prototype.toString.call(hash, opts)
|
|
}).filter(x => x.length).join(sep)
|
|
}).filter(x => x.length).join(sep)
|
|
}
|
|
|
|
concat (integrity, opts) {
|
|
opts = SsriOpts(opts)
|
|
const other = typeof integrity === 'string'
|
|
? integrity
|
|
: stringify(integrity, opts)
|
|
return parse(`${this.toString(opts)} ${other}`, opts)
|
|
}
|
|
|
|
hexDigest () {
|
|
return parse(this, { single: true }).hexDigest()
|
|
}
|
|
|
|
// add additional hashes to an integrity value, but prevent
|
|
// *changing* an existing integrity hash.
|
|
merge (integrity, opts) {
|
|
opts = SsriOpts(opts)
|
|
const other = parse(integrity, opts)
|
|
for (const algo in other) {
|
|
if (this[algo]) {
|
|
if (!this[algo].find(hash =>
|
|
other[algo].find(otherhash =>
|
|
hash.digest === otherhash.digest))) {
|
|
throw new Error('hashes do not match, cannot update integrity')
|
|
}
|
|
} else {
|
|
this[algo] = other[algo]
|
|
}
|
|
}
|
|
}
|
|
|
|
match (integrity, opts) {
|
|
opts = SsriOpts(opts)
|
|
const other = parse(integrity, opts)
|
|
const algo = other.pickAlgorithm(opts)
|
|
return (
|
|
this[algo] &&
|
|
other[algo] &&
|
|
this[algo].find(hash =>
|
|
other[algo].find(otherhash =>
|
|
hash.digest === otherhash.digest
|
|
)
|
|
)
|
|
) || false
|
|
}
|
|
|
|
pickAlgorithm (opts) {
|
|
opts = SsriOpts(opts)
|
|
const pickAlgorithm = opts.pickAlgorithm
|
|
const keys = Object.keys(this)
|
|
if (!keys.length) {
|
|
throw new Error(`No algorithms available for ${
|
|
JSON.stringify(this.toString())
|
|
}`)
|
|
}
|
|
return keys.reduce((acc, algo) => {
|
|
return pickAlgorithm(acc, algo) || acc
|
|
})
|
|
}
|
|
}
|
|
|
|
module.exports.parse = parse
|
|
function parse (sri, opts) {
|
|
opts = SsriOpts(opts)
|
|
if (typeof sri === 'string') {
|
|
return _parse(sri, opts)
|
|
} else if (sri.algorithm && sri.digest) {
|
|
const fullSri = new Integrity()
|
|
fullSri[sri.algorithm] = [sri]
|
|
return _parse(stringify(fullSri, opts), opts)
|
|
} else {
|
|
return _parse(stringify(sri, opts), opts)
|
|
}
|
|
}
|
|
|
|
function _parse (integrity, opts) {
|
|
// 3.4.3. Parse metadata
|
|
// https://w3c.github.io/webappsec-subresource-integrity/#parse-metadata
|
|
if (opts.single) {
|
|
return new Hash(integrity, opts)
|
|
}
|
|
return integrity.trim().split(/\s+/).reduce((acc, string) => {
|
|
const hash = new Hash(string, opts)
|
|
if (hash.algorithm && hash.digest) {
|
|
const algo = hash.algorithm
|
|
if (!acc[algo]) { acc[algo] = [] }
|
|
acc[algo].push(hash)
|
|
}
|
|
return acc
|
|
}, new Integrity())
|
|
}
|
|
|
|
module.exports.stringify = stringify
|
|
function stringify (obj, opts) {
|
|
opts = SsriOpts(opts)
|
|
if (obj.algorithm && obj.digest) {
|
|
return Hash.prototype.toString.call(obj, opts)
|
|
} else if (typeof obj === 'string') {
|
|
return stringify(parse(obj, opts), opts)
|
|
} else {
|
|
return Integrity.prototype.toString.call(obj, opts)
|
|
}
|
|
}
|
|
|
|
module.exports.fromHex = fromHex
|
|
function fromHex (hexDigest, algorithm, opts) {
|
|
opts = SsriOpts(opts)
|
|
const optString = getOptString(opts.options)
|
|
return parse(
|
|
`${algorithm}-${
|
|
Buffer.from(hexDigest, 'hex').toString('base64')
|
|
}${optString}`, opts
|
|
)
|
|
}
|
|
|
|
module.exports.fromData = fromData
|
|
function fromData (data, opts) {
|
|
opts = SsriOpts(opts)
|
|
const algorithms = opts.algorithms
|
|
const optString = getOptString(opts.options)
|
|
return algorithms.reduce((acc, algo) => {
|
|
const digest = crypto.createHash(algo).update(data).digest('base64')
|
|
const hash = new Hash(
|
|
`${algo}-${digest}${optString}`,
|
|
opts
|
|
)
|
|
/* istanbul ignore else - it would be VERY strange if the string we
|
|
* just calculated with an algo did not have an algo or digest.
|
|
*/
|
|
if (hash.algorithm && hash.digest) {
|
|
const algo = hash.algorithm
|
|
if (!acc[algo]) { acc[algo] = [] }
|
|
acc[algo].push(hash)
|
|
}
|
|
return acc
|
|
}, new Integrity())
|
|
}
|
|
|
|
module.exports.fromStream = fromStream
|
|
function fromStream (stream, opts) {
|
|
opts = SsriOpts(opts)
|
|
const istream = integrityStream(opts)
|
|
return new Promise((resolve, reject) => {
|
|
stream.pipe(istream)
|
|
stream.on('error', reject)
|
|
istream.on('error', reject)
|
|
let sri
|
|
istream.on('integrity', s => { sri = s })
|
|
istream.on('end', () => resolve(sri))
|
|
istream.on('data', () => {})
|
|
})
|
|
}
|
|
|
|
module.exports.checkData = checkData
|
|
function checkData (data, sri, opts) {
|
|
opts = SsriOpts(opts)
|
|
sri = parse(sri, opts)
|
|
if (!Object.keys(sri).length) {
|
|
if (opts.error) {
|
|
throw Object.assign(
|
|
new Error('No valid integrity hashes to check against'), {
|
|
code: 'EINTEGRITY'
|
|
}
|
|
)
|
|
} else {
|
|
return false
|
|
}
|
|
}
|
|
const algorithm = sri.pickAlgorithm(opts)
|
|
const digest = crypto.createHash(algorithm).update(data).digest('base64')
|
|
const newSri = parse({ algorithm, digest })
|
|
const match = newSri.match(sri, opts)
|
|
if (match || !opts.error) {
|
|
return match
|
|
} else if (typeof opts.size === 'number' && (data.length !== opts.size)) {
|
|
const err = new Error(`data size mismatch when checking ${sri}.\n Wanted: ${opts.size}\n Found: ${data.length}`)
|
|
err.code = 'EBADSIZE'
|
|
err.found = data.length
|
|
err.expected = opts.size
|
|
err.sri = sri
|
|
throw err
|
|
} else {
|
|
const err = new Error(`Integrity checksum failed when using ${algorithm}: Wanted ${sri}, but got ${newSri}. (${data.length} bytes)`)
|
|
err.code = 'EINTEGRITY'
|
|
err.found = newSri
|
|
err.expected = sri
|
|
err.algorithm = algorithm
|
|
err.sri = sri
|
|
throw err
|
|
}
|
|
}
|
|
|
|
module.exports.checkStream = checkStream
|
|
function checkStream (stream, sri, opts) {
|
|
opts = SsriOpts(opts)
|
|
const checker = integrityStream(opts.concat({
|
|
integrity: sri
|
|
}))
|
|
return new Promise((resolve, reject) => {
|
|
stream.pipe(checker)
|
|
stream.on('error', reject)
|
|
checker.on('error', reject)
|
|
let sri
|
|
checker.on('verified', s => { sri = s })
|
|
checker.on('end', () => resolve(sri))
|
|
checker.on('data', () => {})
|
|
})
|
|
}
|
|
|
|
module.exports.integrityStream = integrityStream
|
|
function integrityStream (opts) {
|
|
return new IntegrityStream(SsriOpts(opts))
|
|
}
|
|
|
|
module.exports.create = createIntegrity
|
|
function createIntegrity (opts) {
|
|
opts = SsriOpts(opts)
|
|
const algorithms = opts.algorithms
|
|
const optString = getOptString(opts.options)
|
|
|
|
const hashes = algorithms.map(crypto.createHash)
|
|
|
|
return {
|
|
update: function (chunk, enc) {
|
|
hashes.forEach(h => h.update(chunk, enc))
|
|
return this
|
|
},
|
|
digest: function (enc) {
|
|
const integrity = algorithms.reduce((acc, algo) => {
|
|
const digest = hashes.shift().digest('base64')
|
|
const hash = new Hash(
|
|
`${algo}-${digest}${optString}`,
|
|
opts
|
|
)
|
|
/* istanbul ignore else - it would be VERY strange if the hash we
|
|
* just calculated with an algo did not have an algo or digest.
|
|
*/
|
|
if (hash.algorithm && hash.digest) {
|
|
const algo = hash.algorithm
|
|
if (!acc[algo]) { acc[algo] = [] }
|
|
acc[algo].push(hash)
|
|
}
|
|
return acc
|
|
}, new Integrity())
|
|
|
|
return integrity
|
|
}
|
|
}
|
|
}
|
|
|
|
const NODE_HASHES = new Set(crypto.getHashes())
|
|
|
|
// This is a Best Effort™ at a reasonable priority for hash algos
|
|
const DEFAULT_PRIORITY = [
|
|
'md5', 'whirlpool', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512',
|
|
// TODO - it's unclear _which_ of these Node will actually use as its name
|
|
// for the algorithm, so we guesswork it based on the OpenSSL names.
|
|
'sha3',
|
|
'sha3-256', 'sha3-384', 'sha3-512',
|
|
'sha3_256', 'sha3_384', 'sha3_512'
|
|
].filter(algo => NODE_HASHES.has(algo))
|
|
|
|
function getPrioritizedHash (algo1, algo2) {
|
|
return DEFAULT_PRIORITY.indexOf(algo1.toLowerCase()) >= DEFAULT_PRIORITY.indexOf(algo2.toLowerCase())
|
|
? algo1
|
|
: algo2
|
|
}
|