/**
* This file is part of Haketilo.
*
* Function: Injecting policy to page by modifying HTTP headers.
*
* Copyright (C) 2021, Wojtek Kosior
* Copyright (C) 2021, jahoti
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* As additional permission under GNU GPL version 3 section 7, you
* may distribute forms of that code without the copy of the GNU
* GPL normally required by section 4, provided you include this
* license notice and, in case of non-source distribution, a URL
* through which recipients can access the Corresponding Source.
* If you modify file(s) with this exception, you may extend this
* exception to your version of the file(s), but you are not
* obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*
* As a special exception to the GPL, any HTML file which merely
* makes function calls to this code, and for that purpose
* includes it by reference shall be deemed a separate work for
* copyright law purposes. If you modify this code, you may extend
* this exception to your version of the code, but you are not
* obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*
*
* I, Wojtek Kosior, thereby promise not to sue for violation of this file's
* license. Although I request that you do not make use this code in a
* proprietary program, I am not going to enforce this in court.
*/
/*
* IMPORTS_START
* IMPORT sign_data
* IMPORT extract_signed
* IMPORT make_csp_rule
* IMPORT csp_header_regex
* IMPORTS_END
*/
function inject_csp_headers(headers, policy)
{
let csp_headers;
let old_signature;
let haketilo_header;
for (const header of headers.filter(h => h.name === "x-haketilo")) {
/* x-haketilo header has format: _0_ */
const match = /^([^_]+)_(0_.*)$/.exec(header.value);
if (!match)
continue;
const result = extract_signed(...match.slice(1, 3));
if (result.fail)
continue;
/* This should succeed - it's our self-produced valid JSON. */
const old_data = JSON.parse(decodeURIComponent(result.data));
/* Confirmed- it's the originals, smuggled in! */
csp_headers = old_data.csp_headers;
old_signature = old_data.policy_sig;
haketilo_header = header;
break;
}
if (policy.has_payload) {
csp_headers = [];
const non_csp_headers = [];
const header_list =
h => csp_header_regex.test(h) ? csp_headers : non_csp_headers;
headers.forEach(h => header_list(h.name).push(h));
headers = non_csp_headers;
} else {
headers.push(...csp_headers || []);
}
if (!haketilo_header) {
haketilo_header = {name: "x-haketilo"};
headers.push(haketilo_header);
}
if (old_signature)
headers = headers.filter(h => h.value.search(old_signature) === -1);
const policy_str = encodeURIComponent(JSON.stringify(policy));
const signed_policy = sign_data(policy_str, new Date().getTime());
const later_30sec = new Date(new Date().getTime() + 30000).toGMTString();
headers.push({
name: "Set-Cookie",
value: `haketilo-${signed_policy.join("=")}; Expires=${later_30sec};`
});
/*
* Smuggle in the signature and 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 headers in the cache.
*/
let haketilo_data = {csp_headers, policy_sig: signed_policy[0]};
haketilo_data = encodeURIComponent(JSON.stringify(haketilo_data));
haketilo_header.value = sign_data(haketilo_data, 0).join("_");
if (!policy.allow) {
headers.push({
name: "content-security-policy",
value: make_csp_rule(policy)
});
}
return headers;
}
/*
* EXPORTS_START
* EXPORT inject_csp_headers
* EXPORTS_END
*/