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authorWojtek Kosior <koszko@koszko.org>2021-06-30 14:12:43 +0200
committerWojtek Kosior <koszko@koszko.org>2021-06-30 14:13:04 +0200
commitcd5272acb47a53ad71e5a6bcbcb4f712bdd285c5 (patch)
tree625f92362000c483719a8b1fb70c23979a8dba60
parent261548ff184926567a623e90df7954aeef842d59 (diff)
downloadbrowser-extension-cd5272acb47a53ad71e5a6bcbcb4f712bdd285c5.tar.gz
browser-extension-cd5272acb47a53ad71e5a6bcbcb4f712bdd285c5.zip
refactor 3 miscellaneous fnctionalities to a their single own file
-rw-r--r--background/policy_injector.js9
-rw-r--r--common/gen_unique.js33
-rw-r--r--common/misc.js59
-rw-r--r--common/url_item.js19
-rw-r--r--content/main.js15
5 files changed, 67 insertions, 68 deletions
diff --git a/background/policy_injector.js b/background/policy_injector.js
index f05a422..4f70aac 100644
--- a/background/policy_injector.js
+++ b/background/policy_injector.js
@@ -14,6 +14,7 @@
* IMPORT gen_unique
* IMPORT url_item
* IMPORT get_query_best
+ * IMPORT csp_rule
* IMPORTS_END
*/
@@ -40,16 +41,12 @@ function inject(details)
if (settings !== undefined && settings.allow)
return {cancel : false};
- let nonce = gen_unique(url).substring(1);
+ let nonce = gen_unique(url);
let headers = details.responseHeaders.filter(is_noncsp_header);
- let rule = `script-src 'nonce-${nonce}';`;
- if (is_chrome)
- rule += `script-src-elem 'nonce-${nonce}';`;
-
headers.push({
name : "content-security-policy",
- value : rule
+ value : csp_rule(nonce)
});
return {responseHeaders: headers};
diff --git a/common/gen_unique.js b/common/gen_unique.js
deleted file mode 100644
index 7ec8b4a..0000000
--- a/common/gen_unique.js
+++ /dev/null
@@ -1,33 +0,0 @@
-/**
- * Myext generating unique, per-site hash
- *
- * Copyright (C) 2021 Wojtek Kosior
- * Redistribution terms are gathered in the `copyright' file.
- */
-
-/*
- * IMPORTS_START
- * IMPORT sha256
- * IMPORT browser
- * IMPORT is_chrome
- * IMPORTS_END
- */
-
-function get_id()
-{
- if (is_chrome)
- return browser.runtime.getManifest().key.substring(0, 50);
- else
- return browser.runtime.getURL("dummy");
-}
-
-function gen_unique(url)
-{
- return "#" + sha256(get_id() + url);
-}
-
-/*
- * EXPORTS_START
- * EXPORT gen_unique
- * EXPORTS_END
- */
diff --git a/common/misc.js b/common/misc.js
new file mode 100644
index 0000000..5754bd0
--- /dev/null
+++ b/common/misc.js
@@ -0,0 +1,59 @@
+/**
+ * Myext miscellaneous operations refactored to a separate file
+ *
+ * Copyright (C) 2021 Wojtek Kosior
+ * Redistribution terms are gathered in the `copyright' file.
+ */
+
+/*
+ * IMPORTS_START
+ * IMPORT sha256
+ * IMPORT browser
+ * IMPORT is_chrome
+ * IMPORTS_END
+ */
+
+/*
+ * generating unique, per-site value that can be computed synchronously
+ * and is impossible to guess for a malicious website
+ */
+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 = /^([^?#]*).*$/;
+ let match = url_re.exec(url);
+ return match[1];
+}
+
+/* csp rule that blocks all scripts except for those injected by us */
+function csp_rule(nonce)
+{
+ let rule = `script-src 'nonce-${nonce}';`;
+ if (is_chrome)
+ rule += `script-src-elem 'nonce-${nonce}';`;
+ return rule;
+}
+
+/*
+ * EXPORTS_START
+ * EXPORT gen_unique
+ * EXPORT url_item
+ * EXPORT csp_rule
+ * EXPORTS_END
+ */
diff --git a/common/url_item.js b/common/url_item.js
deleted file mode 100644
index 102f117..0000000
--- a/common/url_item.js
+++ /dev/null
@@ -1,19 +0,0 @@
-/**
- * Myext stripping url from query and target
- *
- * Copyright (C) 2021 Wojtek Kosior
- * Redistribution terms are gathered in the `copyright' file.
- */
-
-function url_item(url)
-{
- let url_re = /^([^?#]*).*$/;
- let match = url_re.exec(url);
- return match[1];
-}
-
-/*
- * EXPORTS_START
- * EXPORT url_item
- * EXPORTS_END
- */
diff --git a/content/main.js b/content/main.js
index d55ee2e..8525961 100644
--- a/content/main.js
+++ b/content/main.js
@@ -10,6 +10,7 @@
* IMPORT handle_page_actions
* IMPORT url_item
* IMPORT gen_unique
+ * IMPORT csp_rule
* IMPORT sanitize_attributes
* IMPORT script_suppressor
* IMPORT is_chrome
@@ -30,9 +31,8 @@
let url = url_item(document.URL);
let unique = gen_unique(url);
-let nonce = unique.substring(1);
-const suppressor = script_suppressor(nonce);
+const suppressor = script_suppressor(unique);
function needs_blocking()
{
@@ -46,7 +46,7 @@ function needs_blocking()
let second_target = match[4];
if (first_target !== undefined &&
- first_target === unique) {
+ first_target === '#' + unique) {
if (second_target !== undefined)
window.location.href = base_url + second_target;
else
@@ -115,12 +115,7 @@ function inject_csp(head)
let meta = document.createElement("meta");
meta.setAttribute("http-equiv", "Content-Security-Policy");
-
- let rule = `script-src 'nonce-${nonce}'; `;
- if (is_chrome)
- rule += `script-src-elem 'nonce-${nonce}';`;
-
- meta.setAttribute("content", rule);
+ meta.setAttribute("content", csp_rule(unique));
if (head.firstElementChild === null)
head.appendChild(meta);
@@ -144,4 +139,4 @@ if (needs_blocking()) {
addEventListener('beforescriptexecute', suppressor, true);
}
-handle_page_actions(nonce);
+handle_page_actions(unique);