HackMD/lib/csp.js
Sheogorath d4a9bb3c7e
Add data: URL to CSP and upgrade helmet
Seems like the old version of helmet had a problem with `data:`. This
patch upgrades to the latest version and adds the CSP rule to allow
Google Fonts and the offline version of it, to properly include the
fonts and no longer throw ugly error messages at us.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>
2018-10-04 03:04:36 +02:00

100 lines
3.4 KiB
JavaScript

var config = require('./config')
var uuid = require('uuid')
var CspStrategy = {}
var defaultDirectives = {
defaultSrc: ['\'self\''],
scriptSrc: ['\'self\'', 'vimeo.com', 'https://gist.github.com', 'www.slideshare.net', 'https://query.yahooapis.com', '\'unsafe-eval\''],
// ^ TODO: Remove unsafe-eval - webpack script-loader issues https://github.com/hackmdio/codimd/issues/594
imgSrc: ['*'],
styleSrc: ['\'self\'', '\'unsafe-inline\'', 'https://assets-cdn.github.com'], // unsafe-inline is required for some libs, plus used in views
fontSrc: ['\'self\'', 'data:', 'https://public.slidesharecdn.com'],
objectSrc: ['*'], // Chrome PDF viewer treats PDFs as objects :/
mediaSrc: ['*'],
childSrc: ['*'],
connectSrc: ['*']
}
var cdnDirectives = {
scriptSrc: ['https://cdnjs.cloudflare.com', 'https://cdn.mathjax.org'],
styleSrc: ['https://cdnjs.cloudflare.com', 'https://fonts.googleapis.com'],
fontSrc: ['https://cdnjs.cloudflare.com', 'https://fonts.gstatic.com']
}
var disqusDirectives = {
scriptSrc: ['https://*.disqus.com', 'https://*.disquscdn.com'],
styleSrc: ['https://*.disquscdn.com'],
fontSrc: ['https://*.disquscdn.com']
}
var googleAnalyticsDirectives = {
scriptSrc: ['https://www.google-analytics.com']
}
CspStrategy.computeDirectives = function () {
var directives = {}
mergeDirectives(directives, config.csp.directives)
mergeDirectivesIf(config.csp.addDefaults, directives, defaultDirectives)
mergeDirectivesIf(config.useCDN, directives, cdnDirectives)
mergeDirectivesIf(config.csp.addDisqus, directives, disqusDirectives)
mergeDirectivesIf(config.csp.addGoogleAnalytics, directives, googleAnalyticsDirectives)
if (!areAllInlineScriptsAllowed(directives)) {
addInlineScriptExceptions(directives)
}
addUpgradeUnsafeRequestsOptionTo(directives)
addReportURI(directives)
return directives
}
function mergeDirectives (existingDirectives, newDirectives) {
for (var propertyName in newDirectives) {
var newDirective = newDirectives[propertyName]
if (newDirective) {
var existingDirective = existingDirectives[propertyName] || []
existingDirectives[propertyName] = existingDirective.concat(newDirective)
}
}
}
function mergeDirectivesIf (condition, existingDirectives, newDirectives) {
if (condition) {
mergeDirectives(existingDirectives, newDirectives)
}
}
function areAllInlineScriptsAllowed (directives) {
return directives.scriptSrc.indexOf('\'unsafe-inline\'') !== -1
}
function addInlineScriptExceptions (directives) {
directives.scriptSrc.push(getCspNonce)
// TODO: This is the SHA-256 hash of the inline script in build/reveal.js/plugins/notes/notes.html
// Any more clean solution appreciated.
directives.scriptSrc.push('\'sha256-L0TsyAQLAc0koby5DCbFAwFfRs9ZxesA+4xg0QDSrdI=\'')
}
function getCspNonce (req, res) {
return "'nonce-" + res.locals.nonce + "'"
}
function addUpgradeUnsafeRequestsOptionTo (directives) {
if (config.csp.upgradeInsecureRequests === 'auto' && config.useSSL) {
directives.upgradeInsecureRequests = true
} else if (config.csp.upgradeInsecureRequests === true) {
directives.upgradeInsecureRequests = true
}
}
function addReportURI (directives) {
if (config.csp.reportURI) {
directives.reportUri = config.csp.reportURI
}
}
CspStrategy.addNonceToLocals = function (req, res, next) {
res.locals.nonce = uuid.v4()
next()
}
module.exports = CspStrategy