Bug 2070130 - Check final URI in CSS loader mime type quirk. r=dshin

This fixes the Firefox failures in web-platform-tests/wpt#62516.

Implement it behind a pref just-in case. Also, unfortunately we need to
do the same-origin check up-front, because the mime type check can
happen off the main thread.

Pull request: https://github.com/mozilla-firefox/firefox/pull/364

layout/style/Loader.cpp

@@ -278,6 +278,9 @@ SheetLoadData::SheetLoadData(
       mSheetAlreadyComplete(false),
       mLoadFailed(false),
       mShouldEmulateNotificationsForCachedLoad(false),
+      mRecordErrors(
+          aLoader->GetDocument() &&
+          css::ErrorReporter::ShouldReportErrors(*aLoader->GetDocument())),
       mPreloadKind(aPreloadKind),
       mObserver(aObserver),
       mTriggeringPrincipal(aTriggeringPrincipal),
@@ -286,9 +289,6 @@ SheetLoadData::SheetLoadData(
       mFetchPriority{aFetchPriority},
       mGuessedEncoding(GetFallbackEncoding(*aLoader, aOwningNode, nullptr)),
       mCompatMode(aLoader->CompatMode(aPreloadKind)),
-      mRecordErrors(
-          aLoader && aLoader->GetDocument() &&
-          css::ErrorReporter::ShouldReportErrors(*aLoader->GetDocument())),
       mNetworkMetadata(std::move(aNetworkMetadata)) {
   MOZ_ASSERT(!aOwningNode || dom::LinkStyle::FromNode(*aOwningNode),
              "Must implement LinkStyle");
@@ -321,6 +321,9 @@ SheetLoadData::SheetLoadData(
       mSheetAlreadyComplete(false),
       mLoadFailed(false),
       mShouldEmulateNotificationsForCachedLoad(false),
+      mRecordErrors(
+          aLoader->GetDocument() &&
+          css::ErrorReporter::ShouldReportErrors(*aLoader->GetDocument())),
       mPreloadKind(StylePreloadKind::None),
       mObserver(aObserver),
       mTriggeringPrincipal(aTriggeringPrincipal),
@@ -330,9 +333,6 @@ SheetLoadData::SheetLoadData(
       mGuessedEncoding(GetFallbackEncoding(
           *aLoader, nullptr, aParentData ? aParentData->mEncoding : nullptr)),
       mCompatMode(aLoader->CompatMode(mPreloadKind)),
-      mRecordErrors(
-          aLoader && aLoader->GetDocument() &&
-          css::ErrorReporter::ShouldReportErrors(*aLoader->GetDocument())),
       mNetworkMetadata(std::move(aNetworkMetadata)) {
   MOZ_ASSERT(mLoader, "Must have a loader!");
   MOZ_ASSERT(mTriggeringPrincipal);
@@ -367,6 +367,9 @@ SheetLoadData::SheetLoadData(
       mSheetAlreadyComplete(false),
       mLoadFailed(false),
       mShouldEmulateNotificationsForCachedLoad(false),
+      mRecordErrors(
+          aLoader->GetDocument() &&
+          css::ErrorReporter::ShouldReportErrors(*aLoader->GetDocument())),
       mPreloadKind(aPreloadKind),
       mObserver(aObserver),
       mTriggeringPrincipal(aTriggeringPrincipal),
@@ -376,9 +379,6 @@ SheetLoadData::SheetLoadData(
       mGuessedEncoding(
           GetFallbackEncoding(*aLoader, nullptr, aPreloadEncoding)),
       mCompatMode(aLoader->CompatMode(aPreloadKind)),
-      mRecordErrors(
-          aLoader && aLoader->GetDocument() &&
-          css::ErrorReporter::ShouldReportErrors(*aLoader->GetDocument())),
       mNetworkMetadata(std::move(aNetworkMetadata)) {
   MOZ_ASSERT(mTriggeringPrincipal);
   MOZ_ASSERT(mLoader, "Must have a loader!");
@@ -689,6 +689,7 @@ void SheetLoadData::OnStartRequest(nsIRequest* aRequest) {
     }
     return true;
   }());
+  mFinalURISameOrigin = mLoader->LoaderPrincipal()->IsSameOrigin(finalURI);
   if (nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(channel)) {
     nsCString sourceMapURL;
     if (nsContentUtils::GetSourceMapURL(httpChannel, sourceMapURL)) {
@@ -741,24 +742,30 @@ nsresult SheetLoadData::VerifySheetReadyToParse(nsresult aStatus,
                          contentType.EqualsLiteral(UNKNOWN_CONTENT_TYPE) ||
                          contentType.IsEmpty();
   if (!validType) {
-    const bool sameOrigin = mSheet->IsOriginClean();
-    const auto flag = sameOrigin && mCompatMode == eCompatibility_NavQuirks
-                          ? nsIScriptError::warningFlag
-                          : nsIScriptError::errorFlag;
-    const auto errorMessage = flag == nsIScriptError::errorFlag
-                                  ? "MimeNotCss"_ns
-                                  : "MimeNotCssWarn"_ns;
-    NS_ConvertUTF8toUTF16 sheetUri(mURI->GetSpecOrDefault());
-    NS_ConvertUTF8toUTF16 contentType16(contentType);
-
+    const bool shouldAllow = [&] {
+      if (mCompatMode != eCompatibility_NavQuirks) {
+        return false;
+      }
+      if (!mSheet->IsOriginClean()) {
+        return false;
+      }
+      if (StaticPrefs::layout_css_quirks_final_uri_check() &&
+          !mFinalURISameOrigin) {
+        return false;
+      }
+      return true;
+    }();
     nsAutoCString referrerSpec;
     if (nsCOMPtr<nsIURI> referrer = ReferrerInfo()->GetOriginalReferrer()) {
       referrer->GetSpec(referrerSpec);
     }
     mLoader->mReporter->AddConsoleReport(
-        flag, "CSS Loader"_ns, PropertiesFile::CSS_PROPERTIES, referrerSpec, 0,
-        0, errorMessage, {std::move(sheetUri), std::move(contentType16)});
-    if (flag == nsIScriptError::errorFlag) {
+        shouldAllow ? nsIScriptError::warningFlag : nsIScriptError::errorFlag,
+        "CSS Loader"_ns, PropertiesFile::CSS_PROPERTIES, referrerSpec, 0, 0,
+        shouldAllow ? "MimeNotCssWarn"_ns : "MimeNotCss"_ns,
+        {NS_ConvertUTF8toUTF16(mURI->GetSpecOrDefault()),
+         NS_ConvertUTF8toUTF16(contentType)});
+    if (!shouldAllow) {
       LOG_WARN(
           ("  Ignoring sheet with improper MIME type %s", contentType.get()));
       return NS_ERROR_NOT_AVAILABLE;

layout/style/SheetLoadData.h

@@ -206,6 +206,19 @@ class SheetLoadData final
   //   * This load uses a complete cache and no necko activity happens
   bool mShouldEmulateNotificationsForCachedLoad : 1;
 
+  // Whether SheetComplete was called.
+  bool mSheetCompleteCalled : 1 = false;
+
+  // Whether we intentionally are not calling SheetComplete because nobody is
+  // listening for the load.
+  bool mIntentionallyDropped : 1 = false;
+
+  const bool mRecordErrors : 1;
+
+  // Whether our final URI is same-origin with the document that's loading us.
+  // Only relevant for non-inline sheets.
+  bool mFinalURISameOrigin : 1 = false;
+
   // Whether this is a preload, and which kind of preload it is.
   //
   // TODO(emilio): This can become a bitfield once we build with a GCC version
@@ -235,19 +248,10 @@ class SheetLoadData final
   // The quirks mode of the loader at the time the load was triggered.
   const nsCompatibility mCompatMode;
 
-  // Whether SheetComplete was called.
-  bool mSheetCompleteCalled = false;
-
-  // Whether we intentionally are not calling SheetComplete because nobody is
-  // listening for the load.
-  bool mIntentionallyDropped = false;
-
   // The start timestamp for the load, or the timestamp where this load is
   // coalesced into an existing load.
   TimeStamp mLoadStart;
 
-  const bool mRecordErrors;
-
   RefPtr<SubResourceNetworkMetadataHolder> mNetworkMetadata;
 
   bool ShouldDefer() const { return mWasAlternate || !mMediaMatched; }

modules/libpref/init/StaticPrefList.yaml

@@ -10809,6 +10809,13 @@
   mirror: always
   rust: true
 
+# Whether quirks mode check the same-originness of the final uri,
+# see https://github.com/whatwg/html/pull/12468
+- name: layout.css.quirks.final-uri-check
+  type: RelaxedAtomicBool
+  value: true
+  mirror: always
+
 # Should we look for counter ancestor scopes first?
 - name: layout.css.counter-ancestor-scope.enabled
   type: bool

testing/web-platform/meta/html/links/stylesheet/quirk-origin-check-recursive-import.html.ini

@@ -1,3 +0,0 @@
-[quirk-origin-check-recursive-import.html]
-  [Origin check for stylesheet with non-CSS MIME type quirk: recursive @import]
-    expected: FAIL

testing/web-platform/meta/html/links/stylesheet/quirk-origin-check.html.ini

@@ -1,3 +0,0 @@
-[quirk-origin-check.html]
-  [Origin check for stylesheet with non-CSS MIME type quirk]
-    expected: FAIL

testing/web-platform/meta/html/semantics/document-metadata/the-link-element/link-style-data-url-quirks.html.ini

@@ -1,3 +0,0 @@
-[link-style-data-url-quirks.html]
-  [data: URL stylesheet with text/plain is blocked in quirks mode]
-    expected: FAIL