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/**
* Hachette injecting policy to page using webRequest
*
* Copyright (C) 2021 Wojtek Kosior
* Copyright (C) 2021 jahoti
* Redistribution terms are gathered in the `copyright' file.
*/
/*
* IMPORTS_START
* IMPORT TYPE_PREFIX
* IMPORT get_storage
* IMPORT browser
* IMPORT is_chrome
* IMPORT is_mozilla
* IMPORT gen_unique
* IMPORT gen_nonce
* IMPORT is_privileged_url
* IMPORT url_extract_target
* IMPORT sign_policy
* IMPORT get_query_best
* IMPORT parse_csp
* IMPORTS_END
*/
var storage;
var query_best;
const csp_header_names = new Set([
"content-security-policy",
"x-webkit-csp",
"x-content-security-policy"
]);
/* TODO: variable no longer in use; remove if not needed */
const unwanted_csp_directives = new Set([
"report-to",
"report-uri",
"script-src",
"script-src-elem",
"prefetch-src"
]);
const report_only = "content-security-policy-report-only";
function url_inject(details)
{
if (is_privileged_url(details.url))
return;
const targets = url_extract_target(details.url);
if (targets.current)
return;
/* Redirect; update policy */
if (targets.policy)
targets.target = "";
let [pattern, settings] = query_best(targets.base_url);
/* Defaults */
if (!pattern)
settings = {};
const policy = encodeURIComponent(
JSON.stringify({
allow: settings.allow,
nonce: gen_nonce(),
base_url: targets.base_url
})
);
return {
redirectUrl: [
targets.base_url,
'#', sign_policy(policy, new Date()), policy,
targets.target,
targets.target2
].join("")
};
}
function process_csp_header(header, rule, block)
{
const csp = parse_csp(header.value);
/* No snitching */
delete csp['report-to'];
delete csp['report-uri'];
if (block) {
delete csp['script-src'];
delete csp['script-src-elem'];
csp['script-src-attr'] = ["'none'"];
csp['prefetch-src'] = ["'none'"];
}
if ('script-src' in csp)
csp['script-src'].push(rule);
else
csp['script-src'] = [rule];
if ('script-src-elem' in csp)
csp['script-src-elem'].push(rule);
else
csp['script-src-elem'] = [rule];
const new_policy = Object.entries(csp).map(
i => `${i[0]} ${i[1].join(' ')};`
);
return {name: header.name, value: new_policy.join('')};
}
function headers_inject(details)
{
const targets = url_extract_target(details.url);
/* Block mis-/unsigned requests */
if (!targets.current)
return {cancel: true};
let orig_csp_headers = is_chrome ? null : [];
let headers = [];
let csp_headers = is_chrome ? headers : [];
const rule = `'nonce-${targets.policy.nonce}'`;
const block = !targets.policy.allow;
for (const header of details.responseHeaders) {
if (!csp_header_names.has(header)) {
/* Retain all non-snitching headers */
if (header.name.toLowerCase() !== report_only) {
headers.push(header);
/* If these are the original CSP headers, use them instead */
/* Test based on url_extract_target() in misc.js */
if (is_mozilla && header.name === "x-orig-csp") {
let index = header.value.indexOf('%5B');
if (index === -1)
continue;
let sig = header.value.substring(0, index);
let data = header.value.substring(index);
if (sig !== sign_policy(data, 0))
continue;
/* Confirmed- it's the originals, smuggled in! */
try {
data = JSON.parse(decodeURIComponent(data));
} catch (e) {
/* This should not be reached -
it's our self-produced valid JSON. */
console.log("Unexpected internal error - invalid JSON smuggled!", e);
}
orig_csp_headers = csp_headers = null;
for (const header of data)
headers.push(process_csp_header(header, rule, block));
}
}
continue;
}
if (is_mozilla && !orig_csp_headers)
continue;
csp_headers.push(process_csp_header(header, rule, block));
if (is_mozilla)
orig_csp_headers.push(header);
}
if (orig_csp_headers) {
/** Smuggle in the original CSP headers for future use.
* These are signed with a time of 0, as it's not clear there
* is a limit on how long Firefox might retain these headers in
* the cache.
*/
orig_csp_headers = encodeURIComponent(JSON.stringify(orig_csp_headers));
headers.push({
name: "x-orig-csp",
value: sign_policy(orig_csp_headers, 0) + orig_csp_headers
});
headers = headers.concat(csp_headers);
}
/* To ensure there is a CSP header if required */
if (block) {
headers.push({
name: "content-security-policy",
value: `script-src ${rule}; script-src-elem ${rule}; ` +
"script-src-attr 'none'; prefetch-src 'none';"
});
}
return {responseHeaders: headers};
}
async function start_policy_injector()
{
storage = await get_storage();
query_best = await get_query_best();
let extra_opts = ["blocking", "responseHeaders"];
if (is_chrome)
extra_opts.push("extraHeaders");
browser.webRequest.onBeforeRequest.addListener(
url_inject,
{
urls: ["<all_urls>"],
types: ["main_frame", "sub_frame"]
},
["blocking"]
);
browser.webRequest.onHeadersReceived.addListener(
headers_inject,
{
urls: ["<all_urls>"],
types: ["main_frame", "sub_frame"]
},
extra_opts
);
}
/*
* EXPORTS_START
* EXPORT start_policy_injector
* EXPORTS_END
*/
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