Add 64-bit support to browser blacklisting

chrome_elf/blacklist/blacklist.cc

Index: chrome_elf/blacklist/blacklist.cc
diff --git a/chrome_elf/blacklist/blacklist.cc b/chrome_elf/blacklist/blacklist.cc
index c7d1a5d77d16857dff3c874dc103c5b68c1ddad7..6a982cf0b60aa5ee9981ee96accb5b45727f4ebb 100644
--- a/chrome_elf/blacklist/blacklist.cc
+++ b/chrome_elf/blacklist/blacklist.cc
@@ -197,12 +197,6 @@ bool RemoveDllFromBlacklist(const wchar_t* dll_name) {
 }
 
 bool Initialize(bool force) {
-#if defined(_WIN64)
-  // TODO(robertshield): Implement 64-bit support by providing 64-bit
-  //                     interceptors.
-  return false;
-#endif
-
   // Check to see that we found the functions we need in ntdll.
   if (!InitializeInterceptImports())
     return false;
@@ -229,8 +223,11 @@ bool Initialize(bool force) {
   // Create a thunk via the appropriate ServiceResolver instance.
   sandbox::ServiceResolverThunk* thunk;
 #if defined(_WIN64)

[robertshield, 2014/01/07 18:30:47]

This looks very similar to the 32-bit code.

Can we remove the contents of the _WIN64 condition and simply surround the
GetWOW64 check below in "#if defined(_WIN64)"?

[csharp, 2014/01/07 20:43:07]

Done.

-  // TODO(robertshield): Use the appropriate thunk for 64-bit support
-  // when said support is implemented.
+  if (os_info.version() >= VERSION_WIN8) {
+    thunk = new sandbox::Win8ResolverThunk(current_process, kRelaxed);
+  } else {
+    thunk = new sandbox::ServiceResolverThunk(current_process, kRelaxed);
+  }
 #else
   if (GetWOW64StatusForCurrentProcess() == WOW64_ENABLED) {
     if (os_info.version() >= VERSION_WIN8)
@@ -257,16 +254,37 @@ bool Initialize(bool force) {
 
   thunk->AllowLocalPatches();
 
-  // Get ntdll base, target name, interceptor address,
+  // Replace the default NtMapViewOfSection with our patched version.
+#if defined(_WIN64)
   NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
                               reinterpret_cast<void*>(&__ImageBase),
                               "NtMapViewOfSection",
                               NULL,
-                              &blacklist::BlNtMapViewOfSection,
+                              &blacklist::BlNtMapViewOfSection64,
                               thunk_storage,
                               sizeof(sandbox::ThunkData),
                               NULL);
 
+  // Keep a pointer to the original code, we don't have enough space to
+  // add it directly to the call.
+  g_nt_map_view_of_section_func = reinterpret_cast<NtMapViewOfSectionFunction>(
+      thunk_storage);
+
+  // Ensure that the pointer to the old function can't be changed.
+  VirtualProtect(&g_nt_map_view_of_section_func,

[robertshield, 2014/01/07 18:30:47]

consider using the result of this as part of the Initialize function's return
value (similar to |page_executable| below).

[csharp, 2014/01/07 20:43:07]

Done.

+                 sizeof(g_nt_map_view_of_section_func),
+                 PAGE_EXECUTE_READ,
+                 &old_protect);
+#else
+  NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
+                              reinterpret_cast<void*>(&__ImageBase),
+                              "NtMapViewOfSection",
+                              NULL,
+                              &blacklist::BlNtMapViewOfSection,
+                              thunk_storage,
+                              sizeof(sandbox::ThunkData),
+                              NULL);
+#endif
   delete thunk;
 
   // Mark the thunk storage as executable and prevent any future writes to it.