Bug 1504018 - Support unrestricted schemes in permission warnings r=aswan

If an extension with the "mozillaAddons" permission is updated, the
permission diffing logic should support restricted schemes.
Otherwise the MatchPattern will throw and prevent the update from being
installed.

`Extension.comparePermissions` is called with the result of
`.userPermissions`, which in turn is equivalent to the result of the
`manifestPermissions` getter. This already filters out restricted
schemes if needed. Therefore we can unconditionally use
`restrictSchemes:false` in `comparePermissions`.

And update the regexp in formatPermissionStrings to support permissions
that start with "about:", since the "MatchPatternUnestricted" type in
toolkit/components/extensions/schemas/manifest.json supports this,
and the lack of "//" in about:-URLs prevents the scheme from being
matched by the existing pattern.

Depends on D14963

Differential Revision: https://phabricator.services.mozilla.com/D14964

--HG--
extra : moz-landing-system : lando

toolkit/components/extensions/Extension.jsm

@@ -540,10 +540,10 @@ class ExtensionData {
   // Compute the difference between two sets of permissions, suitable
   // for presenting to the user.
   static comparePermissions(oldPermissions, newPermissions) {
-    let oldMatcher = new MatchPatternSet(oldPermissions.origins);
+    let oldMatcher = new MatchPatternSet(oldPermissions.origins, {restrictSchemes: false});
     return {
       // formatPermissionStrings ignores any scheme, so only look at the domain.
-      origins: newPermissions.origins.filter(perm => !oldMatcher.subsumesDomain(new MatchPattern(perm))),
+      origins: newPermissions.origins.filter(perm => !oldMatcher.subsumesDomain(new MatchPattern(perm, {restrictSchemes: false}))),
       permissions: newPermissions.permissions.filter(perm => !oldPermissions.permissions.includes(perm)),
     };
   }
@@ -1105,7 +1105,10 @@ class ExtensionData {
         allUrls = true;
         break;
       }
-      let match = /^[a-z*]+:\/\/([^/]*)\//.exec(permission);
+
+      // Privileged extensions may request access to "about:"-URLs, such as
+      // about:reader.
+      let match = /^[a-z*]+:\/\/([^/]*)\/|^about:/.exec(permission);
       if (!match) {
         throw new Error(`Unparseable host permission ${permission}`);
       }

toolkit/components/extensions/test/xpcshell/test_ext_permission_warnings.js

@@ -201,11 +201,11 @@ add_task(async function privileged_with_mozillaAddons() {
   let manifestPermissions = await getManifestPermissions({
     isPrivileged: true,
     manifest: {
-      permissions: ["mozillaAddons", "mozillaAddons", "mozillaAddons", "resource://*/*", "http://a/"],
+      permissions: ["mozillaAddons", "mozillaAddons", "mozillaAddons", "resource://x/*", "http://a/", "about:reader*"],
     },
   });
   deepEqual(manifestPermissions, {
-    origins: ["resource://*/*", "http://a/"],
+    origins: ["resource://x/*", "http://a/", "about:reader*"],
     permissions: ["mozillaAddons"],
   }, "Expected origins and permissions for privileged add-on with mozillaAddons");
 
@@ -219,7 +219,7 @@ add_task(async function privileged_with_mozillaAddons() {
 add_task(async function unprivileged_with_mozillaAddons() {
   let manifestPermissions = await getManifestPermissions({
     manifest: {
-      permissions: ["mozillaAddons", "mozillaAddons", "mozillaAddons", "resource://*/*", "http://a/"],
+      permissions: ["mozillaAddons", "mozillaAddons", "mozillaAddons", "resource://x/*", "http://a/", "about:reader*"],
     },
   });
   deepEqual(manifestPermissions, {
@@ -291,3 +291,38 @@ add_task(async function update_change_permissions() {
     bundle.formatStringFromName("webextPerms.description.proxy", [DUMMY_APP_NAME], 1),
   ], "Expected permission warnings for new permissions only");
 });
+
+// Tests that a privileged extension with the mozillaAddons permission can be
+// updated without errors.
+add_task(async function update_privileged_with_mozillaAddons() {
+  let warnings = await getPermissionWarningsForUpdate({
+    isPrivileged: true,
+    manifest: {
+      permissions: ["mozillaAddons", "resource://a/"],
+    },
+  }, {
+    isPrivileged: true,
+    manifest: {
+      permissions: ["mozillaAddons", "resource://a/", "resource://b/"],
+    },
+  });
+  deepEqual(warnings, [
+    bundle.formatStringFromName("webextPerms.hostDescription.oneSite", ["b"], 1),
+  ], "Expected permission warnings for new host only");
+});
+
+// Tests that an unprivileged extension cannot get privileged permissions
+// through an update.
+add_task(async function update_unprivileged_with_mozillaAddons() {
+  // Unprivileged
+  let warnings = await getPermissionWarningsForUpdate({
+    manifest: {
+      permissions: ["mozillaAddons", "resource://a/"],
+    },
+  }, {
+    manifest: {
+      permissions: ["mozillaAddons", "resource://a/", "resource://b/"],
+    },
+  });
+  deepEqual(warnings, [], "resource:-scheme is unsupported for unprivileged extensions");
+});