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/**
* This file is part of Haketilo.
*
* Function: Miscellaneous operations refactored to a separate file.
*
* 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 <https://www.gnu.org/licenses/>.
*
* 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 browser
* IMPORT TYPE_NAME
* IMPORT TYPE_PREFIX
* IMPORTS_END
*/
/* Generate a random base64-encoded 128-bit sequence */
function gen_nonce()
{
let randomData = new Uint8Array(16);
crypto.getRandomValues(randomData);
return btoa(String.fromCharCode.apply(null, randomData));
}
/*
* generating unique, per-site value that can be computed synchronously
* and is impossible to guess for a malicious website
*/
/* Uint8toHex is a separate function not exported as (a) it's useful and (b) it will be used in crypto.subtle-based digests */
function Uint8toHex(data)
{
let returnValue = '';
for (let byte of data)
returnValue += ('00' + byte.toString(16)).slice(-2);
return returnValue;
}
function gen_nonce(length=16)
{
let randomData = new Uint8Array(length);
crypto.getRandomValues(randomData);
return Uint8toHex(randomData);
}
/* CSP rule that blocks scripts according to policy's needs. */
function make_csp_rule(policy)
{
let rule = "prefetch-src 'none'; script-src-attr 'none';";
const script_src = policy.nonce !== undefined ?
`'nonce-${policy.nonce}'` : "'none'";
rule += ` script-src ${script_src}; script-src-elem ${script_src};`;
return rule;
}
/* Check if some HTTP header might define CSP rules. */
const csp_header_regex =
/^\s*(content-security-policy|x-webkit-csp|x-content-security-policy)/i;
/*
* Print item together with type, e.g.
* nice_name("s", "hello") → "hello (script)"
*/
function nice_name(prefix, name)
{
return `${name} (${TYPE_NAME[prefix]})`;
}
/* Open settings tab with given item's editing already on. */
function open_in_settings(prefix, name)
{
name = encodeURIComponent(name);
const url = browser.runtime.getURL("html/options.html#" + prefix + name);
window.open(url, "_blank");
}
/*
* Check if url corresponds to a browser's special page (or a directory index in
* case of `file://' protocol).
*/
const privileged_reg =
/^(chrome(-extension)?|moz-extension):\/\/|^about:|^file:\/\/.*\/$/;
const is_privileged_url = url => privileged_reg.test(url);
/* Parse a CSP header */
function parse_csp(csp) {
let directive, directive_array;
let directives = {};
for (directive of csp.split(';')) {
directive = directive.trim();
if (directive === '')
continue;
directive_array = directive.split(/\s+/);
directive = directive_array.shift();
/* The "true" case should never occur; nevertheless... */
directives[directive] = directive in directives ?
directives[directive].concat(directive_array) :
directive_array;
}
return directives;
}
/* Regexes and objects to use as/in schemas for parse_json_with_schema(). */
const nonempty_string_matcher = /.+/;
const matchers = {
sha256: /^[0-9a-f]{64}$/,
nonempty_string: nonempty_string_matcher,
component: [
new RegExp(`^[${TYPE_PREFIX.SCRIPT}${TYPE_PREFIX.BAG}]$`),
nonempty_string_matcher
]
};
/*
* EXPORTS_START
* EXPORT gen_nonce
* EXPORT make_csp_rule
* EXPORT csp_header_regex
* EXPORT nice_name
* EXPORT open_in_settings
* EXPORT is_privileged_url
* EXPORT matchers
* EXPORTS_END
*/
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