fixup! Bug 3455: Add DomainIsolator, for isolating circuit by domain.

Bug 40175: Use first-party isolation on reader view

toolkit/components/tor-launcher/TorDomainIsolator.sys.mjs

@@ -300,6 +300,17 @@ class TorDomainIsolatorImpl {
       const channel = aChannel.QueryInterface(Ci.nsIChannel);
       let firstPartyDomain = channel.loadInfo.originAttributes.firstPartyDomain;
       const userContextId = channel.loadInfo.originAttributes.userContextId;
+      const loadingPrincipalURI = channel.loadInfo.loadingPrincipal?.URI;
+      if (loadingPrincipalURI?.spec.startsWith("about:reader")) {
+        try {
+          const searchParams = new URLSearchParams(loadingPrincipalURI.query);
+          if (searchParams.has("url")) {
+            firstPartyDomain = Services.eTLD.getSchemelessSite(Services.io.newURI(searchParams.get("url")));
+          }
+        } catch (e) {
+          logger.error("Failed to get first party domain for about:reader", e);
+        }
+      }
       if (!firstPartyDomain) {
         firstPartyDomain = CATCHALL_DOMAIN;
         if (Date.now() - this.#catchallDirtySince > CATCHALL_MAX_LIFETIME) {
@@ -629,6 +640,8 @@ class TorDomainIsolatorImpl {
 function getDomainForBrowser(browser) {
   let fpd = browser.contentPrincipal.originAttributes.firstPartyDomain;
 
+  const { documentURI } = browser;
+  if (documentURI && documentURI.schemeIs("about")) {
     // Bug 31562: For neterror or certerror, get the original URL from
     // browser.currentURI and use it to calculate the firstPartyDomain.
     const knownErrors = [
@@ -636,12 +649,7 @@ function getDomainForBrowser(browser) {
       "about:certerror",
       "about:httpsonlyerror",
     ];
-  const { documentURI } = browser;
-  if (
-    documentURI &&
-    documentURI.schemeIs("about") &&
-    knownErrors.some(x => documentURI.spec.startsWith(x))
-  ) {
+    if (knownErrors.some(x => documentURI.spec.startsWith(x))) {
       const knownSchemes = ["http", "https"];
       const currentURI = browser.currentURI;
       if (currentURI && knownSchemes.some(x => currentURI.schemeIs(x))) {
@@ -661,6 +669,16 @@ function getDomainForBrowser(browser) {
           }
         }
       }
+    } else if (documentURI.spec.startsWith("about:reader")) {
+      try {
+        const searchParams = new URLSearchParams(documentURI.query);
+        if (searchParams.has("url")) {
+          fpd = Services.eTLD.getSchemelessSite(Services.io.newURI(searchParams.get("url")));
+        }
+      } catch (e) {
+        logger.error("Failed to get first party domain for about:reader", e);
+      }
+    }
   }
 
   return fpd;