Chrome browser process DLL blacklist.

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
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+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome_elf/blacklist/blacklist.h"
+
+#include <string.h>
+
+#include "base/basictypes.h"
+#include "chrome_elf/blacklist/blacklist_interceptions.h"
+#include "sandbox/win/src/interception_internal.h"
+#include "sandbox/win/src/internal_types.h"
+#include "sandbox/win/src/sandbox_utils.h"
+#include "sandbox/win/src/service_resolver.h"
+
+// http://blogs.msdn.com/oldnewthing/archive/2004/10/25/247180.aspx
+extern "C" IMAGE_DOS_HEADER __ImageBase;
+
+namespace blacklist{
+
+const wchar_t* g_troublesome_dlls[kTroublesomeDllsMaxCount] = {};
+int g_troublesome_dlls_cur_index = 0;
+
+const wchar_t kRegistryBeaconPath[] = L"SOFTWARE\\Google\\Chrome\\BLBeacon";
+
+}  // namespace blacklist
+
+// Allocate storage for thunks in a RWX page of this module to save on doing
+// an extra allocation at run time.
+#pragma section(".crthunk",read,write,execute)
+__declspec(allocate(".crthunk")) sandbox::ThunkData g_thunk_storage;
+
+namespace {
+
+enum Version {
+  VERSION_PRE_XP_SP2 = 0,  // Not supported.
+  VERSION_XP_SP2,
+  VERSION_SERVER_2003, // Also includes XP Pro x64 and Server 2003 R2.
+  VERSION_VISTA,       // Also includes Windows Server 2008.
+  VERSION_WIN7,        // Also includes Windows Server 2008 R2.
+  VERSION_WIN8,        // Also includes Windows Server 2012.
+  VERSION_WIN8_1,      // Code named Windows Blue

[rvargas (doing something else), 2013/12/17 22:09:27]

nit: the code name seems pointless at this point

[robertshield, 2013/12/18 02:34:43]

Done.

+  VERSION_WIN_LAST,    // Indicates error condition.
+};
+
+// Whether a process is running under WOW64 (the wrapper that allows 32-bit
+// processes to run on 64-bit versions of Windows).  This will return
+// WOW64_DISABLED for both "32-bit Chrome on 32-bit Windows" and "64-bit
+// Chrome on 64-bit Windows".  WOW64_UNKNOWN means "an error occurred", e.g.
+// the process does not have sufficient access rights to determine this.
+enum WOW64Status {
+  WOW64_DISABLED,
+  WOW64_ENABLED,
+  WOW64_UNKNOWN,
+};
+
+WOW64Status GetWOW64StatusForCurrentProcess() {
+  typedef BOOL (WINAPI* IsWow64ProcessFunc)(HANDLE, PBOOL);
+  IsWow64ProcessFunc is_wow64_process = reinterpret_cast<IsWow64ProcessFunc>(
+      GetProcAddress(GetModuleHandle(L"kernel32.dll"), "IsWow64Process"));
+  if (!is_wow64_process)
+    return WOW64_DISABLED;
+  BOOL is_wow64 = FALSE;
+  if (!(*is_wow64_process)(GetCurrentProcess(), &is_wow64))
+    return WOW64_UNKNOWN;
+  return is_wow64 ? WOW64_ENABLED : WOW64_DISABLED;
+}
+
+class OSInfo {
+ public:
+  struct VersionNumber {
+    int major;
+    int minor;
+    int build;
+  };
+
+  struct ServicePack {
+    int major;
+    int minor;
+  };
+
+  OSInfo() {
+    OSVERSIONINFOEX version_info = { sizeof(version_info) };
+    GetVersionEx(reinterpret_cast<OSVERSIONINFO*>(&version_info));
+    version_number_.major = version_info.dwMajorVersion;
+    version_number_.minor = version_info.dwMinorVersion;
+    version_number_.build = version_info.dwBuildNumber;
+    if ((version_number_.major == 5) && (version_number_.minor > 0)) {
+      // Treat XP Pro x64, Home Server, and Server 2003 R2 as Server 2003.
+      version_ = (version_number_.minor == 1) ? VERSION_XP_SP2 :
+                                                VERSION_SERVER_2003;
+      if (version_ == VERSION_XP_SP2 && version_info.wServicePackMajor < 2)
+        version_ = VERSION_PRE_XP_SP2;
+    } else if (version_number_.major == 6) {
+      switch (version_number_.minor) {
+        case 0:
+          // Treat Windows Server 2008 the same as Windows Vista.
+          version_ = VERSION_VISTA;
+          break;
+        case 1:
+          // Treat Windows Server 2008 R2 the same as Windows 7.
+          version_ = VERSION_WIN7;
+          break;
+        case 2:
+          // Treat Windows Server 2012 the same as Windows 8.
+          version_ = VERSION_WIN8;
+          break;
+        default:
+          version_ = VERSION_WIN8_1;
+          break;
+      }
+    } else if (version_number_.major > 6) {
+      version_ = VERSION_WIN_LAST;
+    } else {
+      version_ = VERSION_PRE_XP_SP2;
+    }
+
+    service_pack_.major = version_info.wServicePackMajor;
+    service_pack_.minor = version_info.wServicePackMinor;
+  }
+
+  Version version() const { return version_; }
+  VersionNumber version_number() const { return version_number_; }
+  ServicePack service_pack() const { return service_pack_; }
+
+ private:
+  Version version_;
+  VersionNumber version_number_;
+  ServicePack service_pack_;
+
+  DISALLOW_COPY_AND_ASSIGN(OSInfo);
+};
+
+bool IsNonBrowserProcess() {
+  wchar_t* command_line = GetCommandLine();
+  return (command_line && wcsstr(command_line, L"--type"));
+}
+
+}  // namespace
+
+namespace blacklist {
+
+bool CreateBeacon() {
+  HKEY beacon_key = 0;

[rvargas (doing something else), 2013/12/17 22:09:27]

nit: NULL

[robertshield, 2013/12/18 02:34:43]

Done.

+  DWORD disposition = 0;
+  LONG result = ::RegCreateKeyEx(HKEY_CURRENT_USER,
+                                 kRegistryBeaconPath,
+                                 0,
+                                 NULL,
+                                 0,
+                                 KEY_WRITE,
+                                 NULL,
+                                 &beacon_key,
+                                 &disposition);
+  bool success = (result == ERROR_SUCCESS &&
+                  disposition != REG_OPENED_EXISTING_KEY);
+  ::RegCloseKey(beacon_key);

[rvargas (doing something else), 2013/12/17 22:09:27]

Only close the key on ERROR_SUCCESS

[robertshield, 2013/12/18 02:34:43]

Done.

+  return success;
+}
+
+bool ClearBeacon() {
+  LONG result = ::RegDeleteKey(HKEY_CURRENT_USER, kRegistryBeaconPath);
+  return (result == ERROR_SUCCESS);
+}
+
+// Adds the given dll name to the blacklist.

[rvargas (doing something else), 2013/12/17 22:09:27]

drop the comment

[robertshield, 2013/12/18 02:34:43]

Done.

+bool AddDllToBlacklist(const wchar_t* dll_name) {
+  if (g_troublesome_dlls_cur_index >= kTroublesomeDllsMaxCount)
+    return false;
+  for (int i = 0; i < g_troublesome_dlls_cur_index; ++i) {
+    if (!wcscmp(g_troublesome_dlls[i], dll_name))
+      return true;
+  }
+
+  // Copy string to blacklist.
+  wchar_t* str_buffer = new wchar_t[wcslen(dll_name) + 1];
+  wcscpy(str_buffer, dll_name);
+
+  g_troublesome_dlls[g_troublesome_dlls_cur_index] = str_buffer;
+  g_troublesome_dlls_cur_index++;
+  return true;
+}
+
+// Removes the given dll name from the blacklist.

[rvargas (doing something else), 2013/12/17 22:09:27]

ditto

[robertshield, 2013/12/18 02:34:43]

Done.

+bool RemoveDllFromBlacklist(const wchar_t* dll_name) {
+  for (int i = 0; i < g_troublesome_dlls_cur_index; ++i) {
+    if (!wcscmp(g_troublesome_dlls[i], dll_name)) {
+      // Found the thing to remove. Delete it then replace it with the last
+      // element.
+      g_troublesome_dlls_cur_index--;
+      delete[] g_troublesome_dlls[i];
+      g_troublesome_dlls[i] = g_troublesome_dlls[g_troublesome_dlls_cur_index];
+      g_troublesome_dlls[g_troublesome_dlls_cur_index] = NULL;
+      return true;
+    }
+  }
+  return false;
+}
+
+bool Initialize(bool force) {
+#if defined(_WIN64)
+  // TODO(robertshield): Implement 64-bit support by providing 64-bit
+  //                     interceptors.
+  return false;
+#endif
+
+  // Check to see if this is a non-browser process, abort if so.
+  if (IsNonBrowserProcess())
+    return false;
+
+  // Check to see if a beacon is present, abort if so.
+  if (!force && !CreateBeacon())
+    return false;
+
+  // Don't try blacklisting on unsupported OS versions.
+  OSInfo os_info;
+  if (os_info.version() <= VERSION_PRE_XP_SP2)
+    return false;
+
+  // Pseudo-handle, no need to close.
+  HANDLE current_process = ::GetCurrentProcess();
+
+  // Tells the ServiceResolverThunks to patch already patched functions.

[rvargas (doing something else), 2013/12/17 22:09:27]

tiny nit: tell the what? :). I think "resolver" is the critical word, I'm not
even sure why ResolverThunk is called that way instead of Resolver.

[robertshield, 2013/12/18 02:34:43]

Done.

+  const bool kRelaxed = true;
+
+  // Create a thunk via the appropriate ServiceResolver instance.
+  sandbox::ServiceResolverThunk* thunk;
+#if defined(_WIN64)
+  // TODO(robertshield): Use the appropriate thunk for 64-bit support
+  // when said support is implemented.
+#else
+  if (GetWOW64StatusForCurrentProcess() == WOW64_ENABLED) {
+    if (os_info.version() >= VERSION_WIN8)
+      thunk = new sandbox::Wow64W8ResolverThunk(current_process, kRelaxed);
+    else
+      thunk = new sandbox::Wow64ResolverThunk(current_process, kRelaxed);
+  } else if (os_info.version() >= VERSION_WIN8) {
+    thunk = new sandbox::Win8ResolverThunk(current_process, kRelaxed);
+  } else {
+    thunk = new sandbox::ServiceResolverThunk(current_process, kRelaxed);
+  }
+#endif
+
+  thunk->AllowLocalPatches();
+
+  // Get ntdll base, target name, interceptor address,
+  NTSTATUS ret = thunk->Setup(::GetModuleHandle(sandbox::kNtdllName),
+                              reinterpret_cast<void*>(&__ImageBase),
+                              "NtMapViewOfSection",
+                              NULL,
+                              &blacklist::BlNtMapViewOfSection,
+                              reinterpret_cast<BYTE*>(&g_thunk_storage),
+                              sizeof(sandbox::ThunkData),
+                              NULL);
+
+  delete thunk;
+  return NT_SUCCESS(ret);
+}
+
+}  // namespace blacklist