bug 1589824 - pass a typed array to OS.File.writeAtomic in certificate export r=Gijs

OS.File.writeAtomic expects either a utf-8 string or a typed array. This patch
fixes instances in pippki.js in certificate export where this was not
guaranteed to be the case. It also extends the test for this functionality to
cover more cases.

Differential Revision: https://phabricator.services.mozilla.com/D50117

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

browser/components/preferences/in-content/tests/browser_cert_export.js

@@ -16,7 +16,31 @@ function createTemporarySaveDirectory() {
   return saveDir;
 }
 
-add_task(async function checkCertExportWorks() {
+// Create the folder the certificates will be saved into.
+var destDir = createTemporarySaveDirectory();
+registerCleanupFunction(function() {
+  destDir.remove(true);
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+});
+
+function stringOrArrayEquals(actual, expected, message) {
+  is(
+    typeof actual,
+    typeof expected,
+    "actual, expected should have the same type"
+  );
+  if (typeof expected == "string") {
+    is(actual, expected, message);
+  } else {
+    is(actual.toString(), expected.toString(), message);
+  }
+}
+
+var dialogWin;
+var exportButton;
+var expectedCert;
+
+async function setupTest() {
   await openPreferencesViaOpenPreferencesAPI("privacy", { leaveOpen: true });
   let certButton = gBrowser.selectedBrowser.contentDocument.getElementById(
     "viewCertificatesButton"
@@ -26,12 +50,11 @@ add_task(async function checkCertExportWorks() {
     "chrome://pippki/content/certManager.xul"
   );
   certButton.click();
-  let dialogWin = await certDialogLoaded;
+  dialogWin = await certDialogLoaded;
   let doc = dialogWin.document;
   doc.getElementById("certmanagertabs").selectedTab = doc.getElementById(
     "ca_tab"
   );
-  let expectedCert;
   let treeView = doc.getElementById("ca-tree").view;
   // Select any which cert. Ignore parent rows (ie rows without certs):
   for (let i = 0; i < treeView.rowCount; i++) {
@@ -45,38 +68,89 @@ add_task(async function checkCertExportWorks() {
     }
   }
 
-  let exportButton = doc.getElementById("ca_exportButton");
+  exportButton = doc.getElementById("ca_exportButton");
   is(exportButton.disabled, false, "Should enable export button");
-  // Create the folder the link will be saved into.
-  var destDir = createTemporarySaveDirectory();
+}
+
+async function checkCertExportWorks(
+  exportType,
+  encoding,
+  expectedFileContents
+) {
+  MockFilePicker.displayDirectory = destDir;
   var destFile = destDir.clone();
   MockFilePicker.init(window);
-  registerCleanupFunction(function() {
-    MockFilePicker.cleanup();
-    destDir.remove(true);
-  });
-  MockFilePicker.displayDirectory = destDir;
+  MockFilePicker.filterIndex = exportType;
   MockFilePicker.showCallback = function(fp) {
     info("showCallback");
     let fileName = fp.defaultString;
     info("fileName: " + fileName);
     destFile.append(fileName);
     MockFilePicker.setFiles([destFile]);
-    MockFilePicker.filterIndex = 0; // Save an x509 PEM copy of the cert.
     info("done showCallback");
   };
   let finishedExporting = TestUtils.topicObserved("cert-export-finished");
   exportButton.click();
   await finishedExporting;
+  MockFilePicker.cleanup();
   if (destFile && destFile.exists()) {
-    let contents = await OS.File.read(destFile.path, { encoding: "utf-8" });
-    is(
+    let contents = await OS.File.read(destFile.path, { encoding });
+    stringOrArrayEquals(
       contents,
-      dialogWin.getPEMString(expectedCert),
+      expectedFileContents,
       "Should have written correct contents"
     );
+    destFile.remove(false);
   } else {
     ok(false, "No cert saved!");
   }
-  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+}
+
+add_task(setupTest);
+
+add_task(async function checkCertPEMExportWorks() {
+  let expectedContents = dialogWin.getPEMString(expectedCert);
+  await checkCertExportWorks(0, /* 0 = PEM */ "utf-8", expectedContents);
+});
+
+add_task(async function checkCertPEMChainExportWorks() {
+  let expectedContents = dialogWin.getPEMString(expectedCert);
+  await checkCertExportWorks(
+    1, // 1 = PEM chain, but the chain is of length 1
+    "utf-8",
+    expectedContents
+  );
+});
+
+add_task(async function checkCertDERExportWorks() {
+  let expectedContents = Uint8Array.from(expectedCert.getRawDER());
+  await checkCertExportWorks(2, /* 2 = DER */ "", expectedContents);
+});
+
+function stringToTypedArray(str) {
+  let arr = new Uint8Array(str.length);
+  for (let i = 0; i < arr.length; i++) {
+    arr[i] = str.charCodeAt(i);
+  }
+  return arr;
+}
+
+add_task(async function checkCertPKCS7ExportWorks() {
+  let certdb = Cc["@mozilla.org/security/x509certdb;1"].getService(
+    Ci.nsIX509CertDB
+  );
+  let expectedContents = stringToTypedArray(certdb.asPKCS7Blob([expectedCert]));
+  await checkCertExportWorks(3, /* 3 = PKCS7 */ "", expectedContents);
+});
+
+add_task(async function checkCertPKCS7ChainExportWorks() {
+  let certdb = Cc["@mozilla.org/security/x509certdb;1"].getService(
+    Ci.nsIX509CertDB
+  );
+  let expectedContents = stringToTypedArray(certdb.asPKCS7Blob([expectedCert]));
+  await checkCertExportWorks(
+    4, // 4 = PKCS7 chain, but the chain is of length 1
+    "",
+    expectedContents
+  );
 });

security/manager/pki/resources/content/pippki.js

@@ -46,11 +46,16 @@ function viewCertHelper(parent, cert, openingOption = "tab") {
   }
 }
 
-function getPKCS7String(certArray) {
+function getPKCS7Array(certArray) {
   let certdb = Cc["@mozilla.org/security/x509certdb;1"].getService(
     Ci.nsIX509CertDB
   );
-  return certdb.asPKCS7Blob(certArray);
+  let pkcs7String = certdb.asPKCS7Blob(certArray);
+  let pkcs7Array = new Uint8Array(pkcs7String.length);
+  for (let i = 0; i < pkcs7Array.length; i++) {
+    pkcs7Array[i] = pkcs7String.charCodeAt(i);
+  }
+  return pkcs7Array;
 }
 
 function getPEMString(cert) {
@@ -155,13 +160,18 @@ async function exportToFile(parent, cert) {
       }
       break;
     case 2:
-      content = cert.getRawDER();
+      // OS.File.writeAtomic requires a utf-8 string or a typed array.
+      // nsIX509Cert.getRawDER() returns an array (not a typed array), so we
+      // convert it here.
+      content = Uint8Array.from(cert.getRawDER());
       break;
     case 3:
-      content = getPKCS7String([cert]);
+      // getPKCS7Array returns a typed array already, so no conversion is
+      // necessary.
+      content = getPKCS7Array([cert]);
       break;
     case 4:
-      content = getPKCS7String(chain);
+      content = getPKCS7Array(chain);
       break;
     case 0:
     default: