diff options
Diffstat (limited to 'common')
| -rw-r--r-- | common/misc.js | 2 | ||||
| -rw-r--r-- | common/signing.js | 74 |
2 files changed, 1 insertions, 75 deletions
diff --git a/common/misc.js b/common/misc.js index 9ffb7ff..5b0addb 100644 --- a/common/misc.js +++ b/common/misc.js @@ -49,7 +49,7 @@ function gen_nonce(length=16) function make_csp_rule(policy) { let rule = "prefetch-src 'none'; script-src-attr 'none';"; - const script_src = policy.has_payload ? + const script_src = policy.nonce !== undefined ? `'nonce-${policy.nonce}'` : "'none'"; rule += ` script-src ${script_src}; script-src-elem ${script_src};`; return rule; diff --git a/common/signing.js b/common/signing.js deleted file mode 100644 index 11cd442..0000000 --- a/common/signing.js +++ /dev/null @@ -1,74 +0,0 @@ -/** - * This file is part of Haketilo. - * - * Functions: Operations related to "signing" of data. - * - * Copyright (C) 2021 Wojtek Kosior - * Redistribution terms are gathered in the `copyright' file. - */ - -/* - * IMPORTS_START - * IMPORT sha256 - * IMPORT browser - * IMPORT is_mozilla - * IMPORTS_END - */ - -/* - * In order to make certain data synchronously accessible in certain contexts, - * Haketilo smuggles it in string form in places like cookies, URLs and headers. - * When using the smuggled data, we first need to make sure it isn't spoofed. - * For that, we use this pseudo-signing mechanism. - * - * Despite what name suggests, no assymetric cryptography is involved, as it - * would bring no additional benefits and would incur bigger performance - * overhead. Instead, we hash the string data together with some secret value - * that is supposed to be known only by this browser instance. Resulting hash - * sum plays the role of the signature. In the hash we also include current - * time. This way, even if signed data leaks (which shouldn't happen in the - * first place), an attacker won't be able to re-use it indefinitely. - * - * The secret shared between execution contexts has to be available - * synchronously. Under Mozilla, this is the extension's per-session id. Under - * Chromium, this is a dummy web-accessible-resource name that resides in the - * manifest and is supposed to be constructed by each user using a unique value - * (this is done automatically by `build.sh'). - */ - -function get_secret() -{ - if (is_mozilla) - return browser.runtime.getURL("dummy"); - - return chrome.runtime.getManifest().web_accessible_resources - .map(r => /^chromium-key-dummy-file-(.*)/.exec(r)).filter(r => r)[0][1]; -} - -function extract_signed(signature, signed_data) -{ - const match = /^([1-9][0-9]{12}|0)_(.*)$/.exec(signed_data); - if (!match) - return {fail: "bad format"}; - - const result = {time: parseInt(match[1]), data: match[2]}; - if (sign_data(result.data, result.time)[0] !== signature) - result.fail = "bad signature"; - - return result; -} - -/* - * Sign a given string for a given time. Time should be either 0 or in the range - * 10^12 <= time < 10^13. - */ -function sign_data(data, time) { - return [sha256(get_secret() + time + data), `${time}_${data}`]; -} - -/* - * EXPORTS_START - * EXPORT extract_signed - * EXPORT sign_data - * EXPORTS_END - */ |