replace cookies with synchronous XmlHttpRequest as policy smuggling method.

Note: this breaks Mozilla port of Haketilo. Synchronous XmlHttpRequest doesn't work as well there. This will be fixed with dynamically-registered content scripts later.

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
- */