kopia lustrzana https://gitlab.com/rysiekpl/libresilient
103 wiersze
3.9 KiB
JavaScript
103 wiersze
3.9 KiB
JavaScript
/* ========================================================================= *\
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|* === basic-integrity: pre-configured subresource integrity for content === *|
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\* ========================================================================= */
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/**
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* this plugin does not implement any push method
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*/
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// no polluting of the global namespace please
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(function(LRPC){
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// this never changes
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const pluginName = "basic-integrity"
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LRPC.set(pluginName, (LR, init={})=>{
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/*
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* plugin config settings
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*/
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// sane defaults
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let defaultConfig = {
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// list of plugins to wrap
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// this should always contain exactly one element, but still needs to be an array
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// as this is what the Service Worker script expects
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uses: [{
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name: "alt-fetch"
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}],
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// integrity data for each piece of content
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// relative URL -> integrity data (string)
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// integrity data can contain multiple integrity hashes, space-separated, as per:
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// https://w3c.github.io/webappsec-subresource-integrity/#agility
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integrity: {},
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// if an URL has no integrity data associated with it, should it be allowed or not?
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requireIntegrity: true
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}
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// merge the defaults with settings from LibResilientConfig
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let config = {...defaultConfig, ...init}
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// reality check: if no wrapped plugin configured, or more than one, complain
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if (config.uses.length != 1) {
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throw new Error(`Expected exactly one plugin to wrap, but ${config.uses.length} configured.`)
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}
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/**
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* getting content using the wrapped plugin, but providing integrity data
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*/
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let fetchContent = (url, init={}) => {
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LR.log(pluginName, `handling: ${url}`)
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// integrity data
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// a string, where we will combine integrity data from init
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// and from the plugin config, if they exist
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let integrity = ""
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// do we have integrity data in init?
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if ('integrity' in init) {
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integrity = init.integrity
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}
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// do we have integrity data in config?
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if (url in config.integrity) {
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integrity += ' ' + config.integrity[url]
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}
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// some cleanup
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integrity = integrity.trim()
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// reality check
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if (integrity != '') {
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// so we have some integrity data; great, let's use it!
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init.integrity = integrity
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// no integrity data available, are we even allowed to proceed?
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} else if (config.requireIntegrity) {
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// bail if integrity data is not available
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throw new Error(`Integrity data required but not provided for: ${url}`)
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}
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// log
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LR.log(pluginName, `integrity for: ${url}\n- ${integrity}`)
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// fetch using the configured wrapped plugin
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//
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// NOTICE: we have no way of knowing if the wrapped plugin performs any actual integrity check
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// NOTICE: if the wrapped plugin doesn't actually check integrity,
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// NOTICE: setting integrity here is not going to do anything
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return config.uses[0].fetch(url, init)
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}
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// and add ourselves to it
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// with some additional metadata
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return {
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name: pluginName,
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description: `verifying subresource integrity for resources fetched by other plugins`,
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version: 'COMMIT_UNKNOWN',
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fetch: fetchContent,
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uses: config.uses
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}
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})
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// done with not polluting the global namespace
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})(LibResilientPluginConstructors)
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