Bug 1455848 - validate access to DWrite font files in WR and output helpful log messages on failure. r=jrmuizel

gfx/2d/Logging.h

@@ -302,6 +302,23 @@ class Log {
     }
     return *this;
   }
+#ifdef WIN32
+  Log& operator<<(const wchar_t aWStr[]) {
+    if (MOZ_UNLIKELY(LogIt())) {
+      int wLen = (int)wcslen(aWStr);
+      std::vector<char> str;
+      int n = WideCharToMultiByte(0, 0, aWStr, wLen, nullptr, 0, nullptr,
+                                  nullptr);
+      if (n > 0) {
+        std::vector<char> str(n+1);
+        WideCharToMultiByte(0, 0, aWStr, wLen, str.data(), n+1, nullptr,
+                            nullptr);
+        mMessage << str.data();
+      }
+    }
+    return *this;
+  }
+#endif
   Log& operator<<(bool aBool) {
     if (MOZ_UNLIKELY(LogIt())) {
       mMessage << (aBool ? "true" : "false");

gfx/2d/ScaledFontDWrite.cpp

@@ -385,6 +385,56 @@ bool UnscaledFontDWrite::GetWRFontDescriptor(WRFontDescriptorOutput aCb,
     return false;
   }
 
+  // FIXME: Debugging kluge for bug 1455848. Remove once debugged!
+  UINT32 numFiles;
+  hr = mFontFace->GetFiles(&numFiles, nullptr);
+  if (FAILED(hr) || !numFiles) {
+    return false;
+  }
+  std::vector<RefPtr<IDWriteFontFile>> files;
+  files.resize(numFiles);
+  hr = mFontFace->GetFiles(&numFiles, getter_AddRefs(files[0]));
+  if (FAILED(hr)) {
+    return false;
+  }
+  MOZ_ASSERT(familyName.size() >= 1 && familyName.back() == 0);
+  for(auto& file : files) {
+    const void* key;
+    UINT32 keySize;
+    hr = file->GetReferenceKey(&key, &keySize);
+    if (FAILED(hr)) {
+      return false;
+    }
+    RefPtr<IDWriteFontFileLoader> loader;
+    hr = file->GetLoader(getter_AddRefs(loader));
+    if (FAILED(hr)) {
+      return false;
+    }
+    RefPtr<IDWriteLocalFontFileLoader> localLoader;
+    loader->QueryInterface(__uuidof(IDWriteLocalFontFileLoader), (void**)getter_AddRefs(localLoader));
+    if (!localLoader) {
+      return false;
+    }
+    UINT32 pathLen;
+    hr = localLoader->GetFilePathLengthFromKey(key, keySize, &pathLen);
+    if (FAILED(hr)) {
+      return false;
+    }
+    size_t offset = familyName.size();
+    familyName.resize(offset + pathLen + 1);
+    hr = localLoader->GetFilePathFromKey(key, keySize, &familyName[offset], pathLen + 1);
+    if (FAILED(hr)) {
+      return false;
+    }
+    MOZ_ASSERT(familyName.back() == 0);
+    DWORD attribs = GetFileAttributesW(&familyName[offset]);
+    if (attribs == INVALID_FILE_ATTRIBUTES) {
+      gfxCriticalNote << "sending font family \"" << &familyName[0]
+                      << "\" with invalid file \"" << &familyName[offset]
+                      << "\"";
+    }
+  }
+
   // The style information that identifies the font can be encoded easily in
   // less than 32 bits. Since the index is needed for font descriptors, only
   // the family name and style information, pass along the style in the index
@@ -392,7 +442,7 @@ bool UnscaledFontDWrite::GetWRFontDescriptor(WRFontDescriptorOutput aCb,
   // the data payload.
   uint32_t index = weight | (stretch << 16) | (style << 24);
   aCb(reinterpret_cast<const uint8_t*>(familyName.data()),
-      (familyName.size() - 1) * sizeof(WCHAR), index, aBaton);
+      familyName.size() * sizeof(WCHAR), index, aBaton);
   return true;
 }
 

gfx/layers/ipc/PWebRenderBridge.ipdl

@@ -82,6 +82,9 @@ parent:
   async FlushApzRepaints();
   sync GetAPZTestData() returns (APZTestData data);
 
+  // Debugging routine for bug 1455848.
+  async ValidateFontDescriptor(uint8_t[] desc);
+
   async Shutdown();
   sync ShutdownSync();
 child:

gfx/layers/wr/WebRenderBridgeChild.cpp

@@ -225,6 +225,14 @@ static void WriteFontDescriptor(const uint8_t* aData, uint32_t aLength,
 
   *sink->mFontKey = sink->mWrBridge->GetNextFontKey();
 
+#ifdef XP_WIN
+  // FIXME: Debugging kluge for bug 1455848. Remove once debugged!
+  nsTArray<uint8_t> data;
+  data.AppendElements(aData, aLength);
+  sink->mWrBridge->SendValidateFontDescriptor(data);
+  aLength = uint32_t(wcsnlen_s((const wchar_t*)aData, aLength / sizeof(wchar_t)) * sizeof(wchar_t));
+#endif
+
   sink->mResources->AddFontDescriptor(
       *sink->mFontKey, Range<uint8_t>(const_cast<uint8_t*>(aData), aLength),
       aIndex);

gfx/layers/wr/WebRenderBridgeParent.cpp

@@ -35,6 +35,10 @@
 #include "mozilla/webrender/RenderThread.h"
 #include "mozilla/widget/CompositorWidget.h"
 
+#ifdef XP_WIN
+#include "dwrite.h"
+#endif
+
 using mozilla::Telemetry::LABELS_CONTENT_FRAME_TIME_REASON;
 
 #ifdef MOZ_GECKO_PROFILER
@@ -697,6 +701,48 @@ void WebRenderBridgeParent::ObserveSharedSurfaceRelease(
   }
 }
 
+// Debugging kluge for bug 1455848. Remove once debugged!
+mozilla::ipc::IPCResult WebRenderBridgeParent::RecvValidateFontDescriptor(
+    nsTArray<uint8_t>&& aData) {
+  if (mDestroyed) {
+    return IPC_OK();
+  }
+#ifdef XP_WIN
+  nsTArray<uint8_t> data(aData);
+  wchar_t* family = (wchar_t*)data.Elements();
+  size_t remaining = data.Length() / sizeof(wchar_t);
+  size_t familyLength = wcsnlen_s(family, remaining);
+  MOZ_ASSERT(familyLength < remaining && family[familyLength] == 0);
+  remaining -= familyLength + 1;
+  wchar_t* files = family + familyLength + 1;
+  BOOL exists = FALSE;
+  if (RefPtr<IDWriteFontCollection> systemFonts = Factory::GetDWriteSystemFonts()) {
+    UINT32 idx;
+    systemFonts->FindFamilyName(family, &idx, &exists);
+  }
+  if (!remaining) {
+    gfxCriticalNote << (exists ? "found" : "MISSING")
+                    << " font family \"" << family
+                    << "\" has no files!";
+  }
+  while (remaining > 0) {
+    size_t fileLength = wcsnlen_s(files, remaining);
+    MOZ_ASSERT(fileLength < remaining && files[fileLength] == 0);
+    DWORD attribs = GetFileAttributesW(files);
+    if (!exists || attribs == INVALID_FILE_ATTRIBUTES) {
+      gfxCriticalNote << (exists ? "found" : "MISSING")
+                      << " font family \"" << family
+                      << "\" has " << (attribs == INVALID_FILE_ATTRIBUTES ? "INVALID" : "valid")
+                      << " file \"" << files
+                      << "\"";
+    }
+    remaining -= fileLength + 1;
+    files += fileLength + 1;
+  }
+#endif
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult WebRenderBridgeParent::RecvUpdateResources(
     nsTArray<OpUpdateResource>&& aResourceUpdates,
     nsTArray<RefCountedShmem>&& aSmallShmems,

gfx/layers/wr/WebRenderBridgeParent.h

@@ -123,6 +123,9 @@ class WebRenderBridgeParent final : public PWebRenderBridgeParent,
       nsTArray<WebRenderParentCommand>&& commands) override;
   mozilla::ipc::IPCResult RecvGetSnapshot(PTextureParent* aTexture) override;
 
+  mozilla::ipc::IPCResult RecvValidateFontDescriptor(
+      nsTArray<uint8_t>&& aData) override;
+
   mozilla::ipc::IPCResult RecvSetLayersObserverEpoch(
       const LayersObserverEpoch& aChildEpoch) override;