Make chrome_elf use thunks instead of function pointers.

chrome_elf/ntdll_cache.cc

Index: chrome_elf/ntdll_cache.cc
diff --git a/chrome_elf/ntdll_cache.cc b/chrome_elf/ntdll_cache.cc
index e5504421ae420cf6d78b281d4c859df6c0ac2a0b..4fc666d626a06f9083619abb09a7553cd3fece82 100644
--- a/chrome_elf/ntdll_cache.cc
+++ b/chrome_elf/ntdll_cache.cc
@@ -2,15 +2,26 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "chrome_elf/ntdll_cache.h"
+
 #include <stdint.h>
 #include <windows.h>
 
-#include "chrome_elf/ntdll_cache.h"
+#include "base/basictypes.h"
+#include "chrome_elf/thunk_getter.h"
+#include "sandbox/win/src/interception_internal.h"
+#include "sandbox/win/src/internal_types.h"
+#include "sandbox/win/src/service_resolver.h"
+
+// Allocate storage for thunks in a page of this module to save on doing
+// an extra allocation at run time.
+#pragma section(".crthunk",read,execute)
+__declspec(allocate(".crthunk")) sandbox::ThunkData g_nt_thunk_storage;
 
 FunctionLookupTable g_ntdll_lookup;
 
 void InitCache() {
-  HMODULE ntdll_handle = ::GetModuleHandle(L"ntdll.dll");
+  HMODULE ntdll_handle = ::GetModuleHandle(sandbox::kNtdllName);
 
   // To find the Export Address Table address, we start from the DOS header.
   // The module handle is actually the address of the header.
@@ -48,4 +59,28 @@ void InitCache() {
     FARPROC func_addr = reinterpret_cast<FARPROC>(func + base_addr);
     g_ntdll_lookup[std::string(name)] = func_addr;
   }
+
+  const bool kRelaxed = true;
+
+  // Create a thunk via the appropriate ServiceResolver instance.
+  sandbox::ServiceResolverThunk* thunk = GetThunk(kRelaxed);
+
+  if (!thunk)
+    return;
+
+  size_t storage_used;

[robertshield, 2014/02/28 21:02:22]

= 0

[Cait (Slow), 2014/03/03 20:55:11]

Done.

+  NTSTATUS ret = thunk->CopyThunk(::GetModuleHandle(sandbox::kNtdllName),
+                                  "NtCreateFile",
+                                  &g_nt_thunk_storage,
+                                  sizeof(sandbox::ThunkData),
+                                  &storage_used);
+
+  g_ntdll_lookup[std::string("NtCreateFile")] =
+      reinterpret_cast<FARPROC>(&g_nt_thunk_storage);
+
+  //TODO(caitkp): Sanity checks?
+  //EXPECT_EQ(sizeof(sandbox::ThunkData), storage_used);
+
+  // TODO: Check to make sure thunk mem matches ntdll mem..
+  //EXPECT_TRUE(NT_SUCCESS(ret));
 }