Bug 1722050 - Add policy for opening executable files based on domain/extension pairs. r=Gijs,fluent-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D144214

browser/components/enterprisepolicies/Policies.jsm

@@ -986,6 +986,11 @@ var Policies = {
     },
   },
 
+  ExemptDomainFileTypePairsFromFileTypeDownloadWarnings: {
+    // This policy is handled directly in EnterprisePoliciesParent.jsm
+    // and requires no validation (It's done by the schema).
+  },
+
   ExtensionSettings: {
     onBeforeAddons(manager, param) {
       try {

browser/components/enterprisepolicies/schemas/policies-schema.json

@@ -461,6 +461,24 @@
       }
     },
 
+    "ExemptDomainFileTypePairsFromFileTypeDownloadWarnings": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "properties": {
+          "file_extension": {
+            "type": "string"
+          },
+          "domains": {
+            "type": "array",
+            "items": {
+              "type": "string"
+            }
+          }
+        }
+      }
+    },
+
     "Extensions": {
       "type": "object",
       "properties": {

browser/components/enterprisepolicies/tests/xpcshell/test_exempt_domain_file_type_pairs_from_file_type_download_warnings.js

@@ -0,0 +1,66 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function test_exempt_xxx() {
+  await setupPolicyEngineWithJson({
+    policies: {
+      ExemptDomainFileTypePairsFromFileTypeDownloadWarnings: [
+        {
+          file_extension: "jnlp",
+          domains: ["example.com", "www.example.edu"],
+        },
+      ],
+    },
+  });
+  equal(
+    Services.policies.isExemptExecutableExtension(
+      "https://www.example.edu",
+      "jnlp"
+    ),
+    true
+  );
+  equal(
+    Services.policies.isExemptExecutableExtension(
+      "https://example.edu",
+      "jnlp"
+    ),
+    false
+  );
+  equal(
+    Services.policies.isExemptExecutableExtension(
+      "https://example.com",
+      "jnlp"
+    ),
+    true
+  );
+  equal(
+    Services.policies.isExemptExecutableExtension(
+      "https://www.example.com",
+      "jnlp"
+    ),
+    true
+  );
+  equal(
+    Services.policies.isExemptExecutableExtension(
+      "https://wwwexample.com",
+      "jnlp"
+    ),
+    false
+  );
+  equal(
+    Services.policies.isExemptExecutableExtension(
+      "https://www.example.org",
+      "jnlp"
+    ),
+    false
+  );
+  equal(
+    Services.policies.isExemptExecutableExtension(
+      "https://www.example.edu",
+      "exe"
+    ),
+    false
+  );
+});

browser/components/enterprisepolicies/tests/xpcshell/xpcshell.ini

@@ -13,6 +13,7 @@ support-files =
 [test_clear_blocked_cookies.js]
 [test_defaultbrowsercheck.js]
 [test_empty_policy.js]
+[test_exempt_domain_file_type_pairs_from_file_type_download_warnings.js]
 [test_extensions.js]
 [test_extensionsettings.js]
 [test_macosparser_unflatten.js]

browser/locales/en-US/browser/policies/policies-descriptions.ftl

@@ -102,6 +102,8 @@ policy-EnableTrackingProtection = Enable or disable Content Blocking and optiona
 # “lock” means that the user won’t be able to change this setting
 policy-EncryptedMediaExtensions = Enable or disable Encrypted Media Extensions and optionally lock it.
 
+policy-ExemptDomainFileTypePairsFromFileTypeDownloadWarnings = Disable warnings based on file extension for specific file types on domains.
+
 # A “locked” extension can’t be disabled or removed by the user. This policy
 # takes 3 keys (“Install”, ”Uninstall”, ”Locked”), you can either keep them in
 # English or translate them as verbs.

toolkit/components/downloads/DownloadIntegration.jsm

@@ -734,6 +734,17 @@ var DownloadIntegration = {
       fileExtension &&
       fileExtension.toLowerCase() == "exe";
 
+    let isExemptExecutableExtension = false;
+    try {
+      let url = new URL(aDownload.source.url);
+      isExemptExecutableExtension = Services.policies.isExemptExecutableExtension(
+        url.origin,
+        fileExtension?.toLowerCase()
+      );
+    } catch (e) {
+      // Invalid URL, go down the original path.
+    }
+
     // Ask for confirmation if the file is executable, except for .exe on
     // Windows where the operating system will show the prompt based on the
     // security zone.  We do this here, instead of letting the caller handle
@@ -741,9 +752,11 @@ var DownloadIntegration = {
     // first is because of its security nature, so that add-ons cannot forget
     // to do this check.  The second is that the system-level security prompt
     // would be displayed at launch time in any case.
+    // We allow policy to override this behavior for file extensions on specific domains.
     if (
       file.isExecutable() &&
       !isWindowsExe &&
+      !isExemptExecutableExtension &&
       !(await this.confirmLaunchExecutable(file.path))
     ) {
       return;

toolkit/components/enterprisepolicies/EnterprisePoliciesParent.jsm

@@ -427,6 +427,25 @@ EnterprisePoliciesManager.prototype = {
   allowedInstallSource(uri) {
     return InstallSources ? InstallSources.matches(uri) : true;
   },
+
+  isExemptExecutableExtension(origin, extension) {
+    let hostname = new URL(origin)?.hostname;
+    let exemptArray = this.getActivePolicies()
+      ?.ExemptDomainFileTypePairsFromFileTypeDownloadWarnings;
+    if (!hostname || !extension || !exemptArray) {
+      return false;
+    }
+    let domains = exemptArray
+      .filter(item => item.file_extension == extension)
+      .map(item => item.domains)
+      .flat();
+    for (let domain of domains) {
+      if (Services.eTLD.hasRootDomain(hostname, domain)) {
+        return true;
+      }
+    }
+    return false;
+  },
 };
 
 let DisallowedFeatures = {};

toolkit/components/enterprisepolicies/nsIEnterprisePolicies.idl

@@ -65,4 +65,11 @@ interface nsIEnterprisePolicies : nsISupports
    * @returns A boolean - true of the extension may be installed.
    */
   bool allowedInstallSource(in nsIURI uri);
+  /**
+   * Uses ExemptDomainFileTypePairsFromFileTypeDownloadWarnings to determine
+   * if a given file extension is exempted from executable warnings.
+   *
+   * @returns A boolean - true if warnings should not be shown.
+   */
+  bool isExemptExecutableExtension(in ACString origin, in ACString extension);
 };