Bug 1700871 - Only allow focus move for links / form submission iff actually handling user input. r=smaug

The other navigation that allows focus moves (window.open) already goes
through the popup blocker, so that one is fine.

I think given how weird yet conservative other browsers are, this should
be a good trade-off to avoid false positives.

Differential Revision: https://phabricator.services.mozilla.com/D110196

docshell/base/nsDocShell.cpp

@@ -12847,6 +12847,7 @@ nsresult nsDocShell::OnLinkClick(
       aTriggeringPrincipal ? aTriggeringPrincipal : aContent->NodePrincipal());
   loadState->SetPrincipalToInherit(aContent->NodePrincipal());
   loadState->SetCsp(aCsp ? aCsp : aContent->GetCsp());
+  loadState->SetAllowFocusMove(UserActivation::IsHandlingUserInput());
 
   nsCOMPtr<nsIRunnable> ev =
       new OnLinkClickEvent(this, aContent, loadState, noOpenerImplied,
@@ -13011,7 +13012,6 @@ nsresult nsDocShell::OnLinkClickSync(nsIContent* aContent,
   aLoadState->SetTypeHint(NS_ConvertUTF16toUTF8(typeHint));
   aLoadState->SetLoadType(loadType);
   aLoadState->SetSourceBrowsingContext(mBrowsingContext);
-  aLoadState->SetAllowFocusMove(true);
   aLoadState->SetHasValidUserGestureActivation(
       context && context->HasValidTransientUserGestureActivation());
 

dom/base/test/browser.ini

@@ -69,6 +69,7 @@ skip-if =
   os == 'win' && bits == 64 # Bug 1692963
 support-files =
   file_bug1691214.html
+  file_bug1700871.html
 [browser_inputStream_structuredClone.js]
 [browser_multiple_popups.js]
 skip-if = (os == 'win' && !debug) || (os == "mac" && !debug) # Bug 1505235, Bug 1661132 (osx)

dom/base/test/browser_bug1303838.js

@@ -291,19 +291,13 @@ function clickLink(
       waitForLocationChange(targetsFrame, testBrowser, locationChangeNum)
     );
   }
+
+  info("BC children: " + browser.browsingContext.children.length);
   promises.push(
-    SpecialPowers.spawn(
-      browser,
-      [[isFrame, linkId]],
-      ([contentIsFrame, contentLinkId]) => {
-        let doc = content.document;
-        if (contentIsFrame) {
-          let frame = content.document.getElementById("frame");
-          doc = frame.contentDocument;
-        }
-        info("Clicking " + contentLinkId);
-        doc.querySelector(contentLinkId).click();
-      }
+    BrowserTestUtils.synthesizeMouseAtCenter(
+      linkId,
+      {},
+      isFrame ? browser.browsingContext.children[0] : browser
     )
   );
   return Promise.all(promises);

dom/base/test/browser_bug1691214.js

@@ -6,25 +6,28 @@
 
 const BASE_URL = "http://mochi.test:8888/browser/dom/base/test/";
 
-add_task(async function() {
+async function newFocusedWindow() {
+  let delayedStartupPromise = BrowserTestUtils.waitForNewWindow();
+  let win = await BrowserTestUtils.domWindowOpenedAndLoaded();
+  // New windows get focused after the first paint, see bug 1262946
+  await BrowserTestUtils.waitForContentEvent(
+    win.gBrowser.selectedBrowser,
+    "MozAfterPaint"
+  );
+  await delayedStartupPromise;
+  return win;
+}
+
+add_task(async function bug1691214() {
   await BrowserTestUtils.withNewTab(
     BASE_URL + "file_bug1691214.html",
     async function(browser) {
       let win;
 
       {
-        let newWindow = BrowserTestUtils.domWindowOpenedAndLoaded();
-        let delayedStartupPromise = BrowserTestUtils.waitForNewWindow();
-
+        let newWindow = newFocusedWindow();
         await BrowserTestUtils.synthesizeMouseAtCenter("#link-1", {}, browser);
         win = await newWindow;
-        ok(win, "First navigation should've opened the new window");
-        // New windows get focused after the first paint, see bug 1262946
-        await BrowserTestUtils.waitForContentEvent(
-          win.gBrowser.selectedBrowser,
-          "MozAfterPaint"
-        );
-        await delayedStartupPromise;
         is(Services.focus.focusedWindow, win, "New window should be focused");
       }
 
@@ -56,3 +59,42 @@ add_task(async function() {
     }
   );
 });
+
+// The tab has a form infinitely submitting to an iframe, and that shouldn't
+// switch focus back. For that, we open a window from the tab, make sure it's
+// focused, and then wait for three submissions (but since we need to listen to
+// trusted events from chrome code, we use the iframe load event instead).
+add_task(async function bug1700871() {
+  await BrowserTestUtils.withNewTab(
+    BASE_URL + "file_bug1700871.html",
+    async function(browser) {
+      let win;
+
+      {
+        let newWindow = newFocusedWindow();
+        await BrowserTestUtils.synthesizeMouseAtCenter("#link-1", {}, browser);
+        win = await newWindow;
+        is(Services.focus.focusedWindow, win, "New window should be focused");
+      }
+
+      info("waiting for three submit events and ensuring focus hasn't moved");
+
+      await SpecialPowers.spawn(browser, [], function() {
+        let pending = 3;
+        return new Promise(resolve => {
+          content.document
+            .querySelector("iframe")
+            .addEventListener("load", function(e) {
+              info("Got load on the frame: " + pending);
+              if (!--pending) {
+                resolve();
+              }
+            });
+        });
+      });
+
+      is(Services.focus.focusedWindow, win, "Focus shouldn't have moved");
+      win.close();
+    }
+  );
+});

dom/base/test/file_bug1303838.html

@@ -6,20 +6,29 @@ Tests for tab switching on link clicks.
 <head>
   <meta charset="utf-8">
   <title>Tests for tab switching on link clicks.</title>
+  <style>
+    a {
+      display: inline-block;
+      width: 10px;
+      height: 10px;
+      overflow: hidden;
+      background-color: currentColor;
+    }
+  </style>
 </head>
 <body>
-  <a id="link-1" target="testTab" href="file_bug1303838_target_foo.html">Link 1</a><br>
-  <a id="link-2" target="testTab" href="file_bug1303838_target_bar.html">Link 2</a><br>
-  <a id="link-3" target="testTab" href="file_bug1303838_target_baz.html">Link 3</a><br>
-  <a id="link-4" href="#" onclick="testTab = window.open('file_bug1303838_target_foo.html', 'testTab'); return false;">Link 4</a><br>
-  <a id="link-5" href="#" onclick="testTab.location.href += '?1'; return false;">Link 5</a><br>
-  <a id="link-6" href="#" onclick="testTab.location.href += '#1'; return false;">Link 6</a><br>
-  <a id="link-7" target="testTab" href="file_bug1303838_target.html">Link 7</a><br>
-  <a id="anchor-link-1" target="testTab" href="file_bug1303838_target.html#foo">Anchor Link 1</a><br>
-  <a id="anchor-link-2" target="testTab" href="file_bug1303838_target.html#bar">Anchor Link 2</a><br>
-  <a id="anchor-link-3" target="testTab" href="file_bug1303838_target.html#baz">Anchor Link 3</a><br>
-  <a id="frame-link-1" target="testFrame" href="file_bug1303838_target_ifoo.html">Frame Link 1</a><br>
-  <a id="frame-link-2" target="testFrame" href="file_bug1303838_target_ibar.html">Frame Link 2</a><br>
-  <a id="frame-link-3" target="testFrame" href="file_bug1303838_target_ibaz.html">Frame Link 3</a><br>
+  <a id="link-1" target="testTab" href="file_bug1303838_target_foo.html">Link 1</a>,
+  <a id="link-2" target="testTab" href="file_bug1303838_target_bar.html">Link 2</a>,
+  <a id="link-3" target="testTab" href="file_bug1303838_target_baz.html">Link 3</a>,
+  <a id="link-4" href="#" onclick="testTab = window.open('file_bug1303838_target_foo.html', 'testTab'); return false;">Link 4</a>,
+  <a id="link-5" href="#" onclick="testTab.location.href += '?1'; return false;">Link 5</a>,
+  <a id="link-6" href="#" onclick="testTab.location.href += '#1'; return false;">Link 6</a>,
+  <a id="link-7" target="testTab" href="file_bug1303838_target.html">Link 7</a>,
+  <a id="anchor-link-1" target="testTab" href="file_bug1303838_target.html#foo">Anchor Link 1</a>,
+  <a id="anchor-link-2" target="testTab" href="file_bug1303838_target.html#bar">Anchor Link 2</a>,
+  <a id="anchor-link-3" target="testTab" href="file_bug1303838_target.html#baz">Anchor Link 3</a>,
+  <a id="frame-link-1" target="testFrame" href="file_bug1303838_target_ifoo.html">Frame Link 1</a>,
+  <a id="frame-link-2" target="testFrame" href="file_bug1303838_target_ibar.html">Frame Link 2</a>,
+  <a id="frame-link-3" target="testFrame" href="file_bug1303838_target_ibaz.html">Frame Link 3</a>,
 </body>
 </html>

dom/base/test/file_bug1700871.html

@@ -0,0 +1,18 @@
+<!doctype html>
+<a id="link-1" href="?1" onclick="window.open(this.href, 'childWin', 'height=300,width=600'); return false;">Open in window.</a>
+<form target="frame" method="get">
+  <input type=hidden name=counter value=0>
+  <iframe name="frame" href="file_bug1700871.html"></iframe>
+</form>
+<script>
+  (function submitForm() {
+    if (location.search) {
+      return; // Don't fork-bomb ourselves.
+    }
+
+    let counter = document.querySelector("input");
+    counter.value = ++counter.value;
+    document.querySelector("form").submit();
+    setTimeout(submitForm, 500);
+  }());
+</script>

dom/html/HTMLFormElement.cpp

@@ -825,6 +825,7 @@ nsresult HTMLFormElement::SubmitSubmission(
     loadState->SetTriggeringPrincipal(NodePrincipal());
     loadState->SetPrincipalToInherit(NodePrincipal());
     loadState->SetCsp(GetCsp());
+    loadState->SetAllowFocusMove(UserActivation::IsHandlingUserInput());
 
     rv = nsDocShell::Cast(container)->OnLinkClickSync(this, loadState, false,
                                                       NodePrincipal());