Bug 1845117 - re-introduce https and replacement character requirements for uriTemplates, r=mkaply

Differential Revision: https://phabricator.services.mozilla.com/D184381

uriloader/exthandler/ExtHandlerService.sys.mjs

@@ -158,6 +158,24 @@ HandlerService.prototype = {
       }
       let { handlers } = existingSchemeInfo;
       for (let newHandler of localeHandlers.schemes[scheme].handlers) {
+        if (!newHandler.uriTemplate) {
+          console.error(
+            `Ignoring protocol handler for ${scheme} without a uriTemplate!`
+          );
+          continue;
+        }
+        if (!newHandler.uriTemplate.startsWith("https://")) {
+          console.error(
+            `Ignoring protocol handler for ${scheme} with insecure template URL ${newHandler.uriTemplate}.`
+          );
+          continue;
+        }
+        if (!newHandler.uriTemplate.toLowerCase().includes("%s")) {
+          console.error(
+            `Ignoring protocol handler for ${scheme} with invalid template URL ${newHandler.uriTemplate}.`
+          );
+          continue;
+        }
         // If there is already a handler registered with the same template
         // URL, ignore the new one:
         let matchingTemplate = handler =>

uriloader/exthandler/tests/unit/test_defaults_handlerService.js

@@ -157,3 +157,46 @@ add_task(async function test_migrations() {
   );
   await deleteHandlerStore();
 });
+
+/**
+ * Check that non-https templates or ones without a '%s' are ignored.
+ */
+add_task(async function invalid_handlers_are_rejected() {
+  let schemes = kHandlerList.default.schemes;
+  schemes.myfancyinvalidstuff = {
+    handlers: [
+      {
+        name: "No template at all",
+      },
+      {
+        name: "Not secure",
+        uriTemplate: "http://example.com/%s",
+      },
+      {
+        name: "No replacement percent-s bit",
+        uriTemplate: "https://example.com/",
+      },
+      {
+        name: "Actually valid",
+        uriTemplate: "https://example.com/%s",
+      },
+    ],
+  };
+  gHandlerService.wrappedJSObject._injectDefaultProtocolHandlers();
+  // Now check the result:
+  let handler = gExternalProtocolService.getProtocolHandlerInfo(
+    "myfancyinvalidstuff"
+  );
+
+  let expectedURIs = ["https://example.com/%s"];
+
+  Assert.deepEqual(
+    Array.from(
+      handler.possibleApplicationHandlers.enumerate(Ci.nsIWebHandlerApp),
+      e => e.uriTemplate
+    ),
+    expectedURIs,
+    "Should have seen only 1 handler added."
+  );
+  await deleteHandlerStore();
+});