Revert changes to content/main.js to commit 25817b68c* - browser-extension - A Web Extension to facilitate replacing sites' js with user-supplied scripts


summary refs log tree commit diff

path: root/content/activity_info_server.js

diff options

author	jahoti <jahoti@tilde.team>	2021-08-14 00:00:00 +0000
committer	jahoti <jahoti@tilde.team>	2021-08-14 00:00:00 +0000
commit	6fda8ea58575e52e8957e6b5bfbdcde8b71d0106 (patch)
tree	b929a18d024a564459b32f272a49516ece84c3c7 /content/activity_info_server.js
parent	5b419aedd564e6506aa2fc8bddcaa5d601888f17 (diff)
download	browser-extension-6fda8ea58575e52e8957e6b5bfbdcde8b71d0106.tar.gz browser-extension-6fda8ea58575e52e8957e6b5bfbdcde8b71d0106.zip

Revert changes to content/main.js to commit 25817b68c*

It turns out modifying the CSP headers in meta tags has no effect.

Diffstat (limited to 'content/activity_info_server.js')

0 files changed, 0 insertions, 0 deletions

id='n132' href='#n132'>132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189

/**
 * Hachette miscellaneous operations refactored to a separate file
 *
 * Copyright (C) 2021 Wojtek Kosior
 * Copyright (C) 2021 jahoti
 * Redistribution terms are gathered in the `copyright' file.
 */

/*
 * IMPORTS_START
 * IMPORT sha256
 * IMPORT browser
 * IMPORT is_chrome
 * IMPORT TYPE_NAME
 * 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) // Default 16
{
    let randomData = new Uint8Array(length || 16);
    crypto.getRandomValues(randomData);
    return Uint8toHex(randomData);
}

function gen_unique(url)
{
    return sha256(get_secure_salt() + url);
}

function get_secure_salt()
{
    if (is_chrome)
	return browser.runtime.getManifest().key.substring(0, 50);
    else
	return browser.runtime.getURL("dummy");
}

/*
 * stripping url from query and target (everything after `#' or `?'
 * gets removed)
 */
function url_item(url)
{
    let url_re = /^([^?#]*).*$/;
    let match = url_re.exec(url);
    return match[1];
}

/*
 * Assume a url like:
 *     https://example.com/green?illuminati=confirmed#<injected-policy>#winky
 * This function will make it into an object like:
 * {
 *     "base_url": "https://example.com/green?illuminati=confirmed",
 *     "target":   "#<injected-policy>",
 *     "target2":  "#winky",
 *     "policy":   <injected-policy-as-js-object>,
 *     "current":  <boolean-indicating-whether-policy-url-matches>
 * }
 * In case url doesn't have 2 #'s, target2 and target can be set to undefined.
 */
function url_extract_target(url)
{
    const url_re = /^([^#]*)((#[^#]*)(#.*)?)?$/;
    const match = url_re.exec(url);
    const targets  = {
	base_url: match[1],
	target:   match[3] || "",
	target2:  match[4] || ""
    };
    if (!targets.target)
	return targets;

    /* %7B -> { */
    const index = targets.target.indexOf('%7B');
    if (index === -1)
	return targets;

    const now = new Date();
    const sig = targets.target.substring(1, index);
    const policy = targets.target.substring(index);
    if (sig !== sign_policy(policy, now) &&
	sig !== sign_policy(policy, now, -1))
	return targets;

    try {
	targets.policy = JSON.parse(decodeURIComponent(policy));
	targets.current = targets.policy.base_url === targets.base_url;
    } catch (e) {
	/* This should not be reached - it's our self-produced valid JSON. */
	console.log("Unexpected internal error - invalid JSON smuggled!", e);
    }

    return targets;
}

/* csp rule that blocks all scripts except for those injected by us */
function csp_rule(nonce)
{
    let rule = `script-src 'nonce-${nonce}';`;
    if (is_chrome)
	rule += `script-src-elem 'nonce-${nonce}';`;
    return rule;
}

/*
 * 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 */
function is_privileged_url(url)
{
    return !!/^(chrome(-extension)?|moz-extension):\/\/|^about:/i.exec(url);
}

/* Sign a given policy for a given time */
function sign_policy(policy, now, hours_offset) {
    let time = Math.floor(now / 3600000) + (hours_offset || 0);
    return gen_unique(time + policy);
}

/* 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;
}

/*
 * EXPORTS_START
 * EXPORT gen_nonce
 * EXPORT gen_unique
 * EXPORT url_item
 * EXPORT url_extract_target
 * EXPORT sign_policy
 * EXPORT csp_rule
 * EXPORT nice_name
 * EXPORT open_in_settings
 * EXPORT is_privileged_url
 * EXPORT parse_csp
 * EXPORTS_END
 */