Use LOAD_LIBRARY_SEARCH_SYSTEM32 for system DLL loads

To avoid DLL search order attacks, always load system DLLs like
d3d11.dll, d3d12.dll by passing LOAD_LIBRARY_SEARCH_SYSTEM32 to LoadLibraryExW.

Change-Id: I0af9f26bb070ea745ec97c23578047543961084f
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/229734
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Rafael Cintron <rafael.cintron@microsoft.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>

src/dawn/common/DynamicLib.cpp

diff --git a/src/dawn/common/DynamicLib.cpp b/src/dawn/common/DynamicLib.cpp
index 7d823db..d700aa0 100644
--- a/src/dawn/common/DynamicLib.cpp
+++ b/src/dawn/common/DynamicLib.cpp
@@ -61,6 +61,18 @@
     return mHandle != nullptr;
 }
 
+#if DAWN_PLATFORM_IS(WINDOWS) && !DAWN_PLATFORM_IS(WINUWP)
+bool DynamicLib::OpenSystemLibrary(std::wstring_view filename, std::string* error) {
+    // Force LOAD_LIBRARY_SEARCH_SYSTEM32 for system libraries to avoid DLL search path
+    // attacks.
+    mHandle = ::LoadLibraryExW(filename.data(), nullptr, LOAD_LIBRARY_SEARCH_SYSTEM32);
+    if (mHandle == nullptr && error != nullptr) {
+        *error = "Windows Error: " + std::to_string(GetLastError());
+    }
+    return mHandle != nullptr;
+}
+#endif
+
 bool DynamicLib::Open(const std::string& filename, std::string* error) {
 #if DAWN_PLATFORM_IS(WINDOWS)
 #if DAWN_PLATFORM_IS(WINUWP)

src/dawn/common/DynamicLib.h

diff --git a/src/dawn/common/DynamicLib.h b/src/dawn/common/DynamicLib.h
index 7197221..8f89eb2 100644
--- a/src/dawn/common/DynamicLib.h
+++ b/src/dawn/common/DynamicLib.h
@@ -32,6 +32,7 @@
 #include <type_traits>
 
 #include "dawn/common/Assert.h"
+#include "dawn/common/Platform.h"
 
 namespace dawn {
 
@@ -48,6 +49,9 @@
 
     bool Valid() const;
 
+#if DAWN_PLATFORM_IS(WINDOWS) && !DAWN_PLATFORM_IS(WINUWP)
+    bool OpenSystemLibrary(std::wstring_view filename, std::string* error = nullptr);
+#endif
     bool Open(const std::string& filename, std::string* error = nullptr);
     void Close();
 

src/dawn/native/d3d/PlatformFunctions.cpp

diff --git a/src/dawn/native/d3d/PlatformFunctions.cpp b/src/dawn/native/d3d/PlatformFunctions.cpp
index f63bbeb..5efe68e 100644
--- a/src/dawn/native/d3d/PlatformFunctions.cpp
+++ b/src/dawn/native/d3d/PlatformFunctions.cpp
@@ -80,7 +80,7 @@
     createDxgiFactory2 = &CreateDXGIFactory2;
 #else
     std::string error;
-    if (!mDXGILib.Open("dxgi.dll", &error) ||
+    if (!mDXGILib.OpenSystemLibrary(L"dxgi.dll", &error) ||
         !mDXGILib.GetProc(&dxgiGetDebugInterface1, "DXGIGetDebugInterface1", &error) ||
         !mDXGILib.GetProc(&createDxgiFactory2, "CreateDXGIFactory2", &error)) {
         return DAWN_INTERNAL_ERROR(error.c_str());

src/dawn/native/d3d11/PlatformFunctionsD3D11.cpp

diff --git a/src/dawn/native/d3d11/PlatformFunctionsD3D11.cpp b/src/dawn/native/d3d11/PlatformFunctionsD3D11.cpp
index c917f93..d843218 100644
--- a/src/dawn/native/d3d11/PlatformFunctionsD3D11.cpp
+++ b/src/dawn/native/d3d11/PlatformFunctionsD3D11.cpp
@@ -46,7 +46,7 @@
     d3d11CreateDevice = &D3D11CreateDevice;
 #else
     std::string error;
-    if (!mD3D11Lib.Open("d3d11.dll", &error) ||
+    if (!mD3D11Lib.OpenSystemLibrary(L"d3d11.dll", &error) ||
         !mD3D11Lib.GetProc(&d3d11CreateDevice, "D3D11CreateDevice", &error)) {
         return DAWN_INTERNAL_ERROR(error.c_str());
     }

src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp

diff --git a/src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp b/src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp
index 1cf1c60..c84c8e4 100644
--- a/src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp
+++ b/src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp
@@ -131,7 +131,7 @@
     d3d12CreateVersionedRootSignatureDeserializer = &D3D12CreateVersionedRootSignatureDeserializer;
 #else
     std::string error;
-    if (!mD3D12Lib.Open("d3d12.dll", &error) ||
+    if (!mD3D12Lib.OpenSystemLibrary(L"d3d12.dll", &error) ||
         !mD3D12Lib.GetProc(&d3d12CreateDevice, "D3D12CreateDevice", &error) ||
         !mD3D12Lib.GetProc(&d3d12GetDebugInterface, "D3D12GetDebugInterface", &error) ||
         !mD3D12Lib.GetProc(&d3d12SerializeRootSignature, "D3D12SerializeRootSignature", &error) ||
@@ -153,7 +153,7 @@
     d3d11on12CreateDevice = &D3D11On12CreateDevice;
 #else
     std::string error;
-    if (!mD3D11Lib.Open("d3d11.dll", &error) ||
+    if (!mD3D11Lib.OpenSystemLibrary(L"d3d11.dll", &error) ||
         !mD3D11Lib.GetProc(&d3d11on12CreateDevice, "D3D11On12CreateDevice", &error)) {
         return DAWN_INTERNAL_ERROR(error.c_str());
     }