Should fix some race conditions causing corruptions in non-HTML non-XML documents.

hackademix · hackademix · commit 9568584751a9 · 2020-09-07T23:22:03.000+02:00
diff --git a/src/content/DocumentCSP.js b/src/content/DocumentCSP.js
@@ -33,6 +33,9 @@ class DocumentCSP {
     let root = document.documentElement;
     try {
       if (!(document instanceof HTMLDocument)) {
+        if (!(document instanceof XMLDocument)) {
+          return false; // nothing to do with ImageDocument, for instance
+        }
         // non-HTML XML documents ignore <meta> CSP unless wrapped in
         // - <html><head></head></head> on Gecko
         // - just <head></head> on Chromium
diff --git a/src/content/syncFetchPolicy.js b/src/content/syncFetchPolicy.js
@@ -24,6 +24,7 @@
       ns.on("capabilities", () => {
 
         let {readyState} = document;
+
         debug("Readystate: %s, suppressedScripts = %s, canScript = %s", readyState, DocumentFreezer.suppressedScripts, ns.canScript);
 
         if (!ns.canScript) {
@@ -45,6 +46,12 @@
             try {
               let doc = window.wrappedJSObject.document;
               removeEventListener("DOMContentLoaded", softReload, true);
+
+              let isDir = document.querySelector("link[rel=stylesheet][href^='chrome:']")
+                  && document.querySelector(`base[href^="${url}"]`);
+              if (isDir || document.contentType !== "text/html") {
+                throw new Error(`Can't document.write() on ${isDir ? "directory listings" : document.contentType}`)
+              }
               doc.open();
               console.debug("Opened", doc.documentElement);
               DocumentFreezer.unfreeze();
@@ -55,7 +62,7 @@
                 debug("Written", html)
               })();
             } catch (e) {
-              debug("Can't use document.write(), XML document?");
+              debug("Can't use document.write(), XML document?", e);
               try {
                 DocumentFreezer.unfreeze();
                 let scripts = [], deferred = [];
