rlz/win/lib/registry_util.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4 //
   5 // A helper library to keep track of a user's key by SID.
   6 // Used by RLZ libary. Also to be used by SearchWithGoogle library.
   7
   8 #include "rlz/win/lib/registry_util.h"
   9
  10 #include "base/process/process_handle.h"
  11 #include "base/strings/utf_string_conversions.h"
  12 #include "base/win/registry.h"
  13 #include "base/win/windows_version.h"
  14 #include "rlz/lib/assert.h"
  15 #include "rlz/win/lib/process_info.h"
  16
  17 namespace rlz_lib {
  18
  19 bool RegKeyReadValue(base::win::RegKey& key, const wchar_t* name,
  20                      char* value, size_t* value_size) {
  21   value[0] = 0;
  22
  23   std::wstring value_string;
  24   if (key.ReadValue(name, &value_string) != ERROR_SUCCESS) {
  25     return false;
  26   }
  27
  28   if (value_string.length() > *value_size) {
  29     *value_size = value_string.length();
  30     return false;
  31   }
  32
  33   // Note that RLZ string are always ASCII by design.
  34   strncpy(value, base::WideToUTF8(value_string).c_str(), *value_size);
  35   value[*value_size - 1] = 0;
  36   return true;
  37 }
  38
  39 bool RegKeyWriteValue(base::win::RegKey& key, const wchar_t* name,
  40                       const char* value) {
  41   std::wstring value_string(base::ASCIIToWide(value));
  42   return key.WriteValue(name, value_string.c_str()) == ERROR_SUCCESS;
  43 }
  44
  45 bool HasUserKeyAccess(bool write_access) {
  46   // The caller is trying to access HKEY_CURRENT_USER.  Test to see if we can
  47   // read from there.  Don't try HKEY_CURRENT_USER because this will cause
  48   // problems in the unit tests: if we open HKEY_CURRENT_USER directly here,
  49   // the overriding done for unit tests will no longer work.  So we try subkey
  50   // "Software" which is known to always exist.
  51   base::win::RegKey key;
  52   if (key.Open(HKEY_CURRENT_USER, L"Software", KEY_READ) != ERROR_SUCCESS)
  53     ASSERT_STRING("Could not open HKEY_CURRENT_USER");
  54
  55   if (ProcessInfo::IsRunningAsSystem()) {
  56     ASSERT_STRING("UserKey::HasAccess: No access as SYSTEM without SID set.");
  57     return false;
  58   }
  59
  60   if (write_access) {
  61     if (base::win::GetVersion() < base::win::VERSION_VISTA) return true;
  62     base::ProcessHandle process_handle = base::GetCurrentProcessHandle();
  63     base::IntegrityLevel level = base::INTEGRITY_UNKNOWN;
  64
  65     if (!base::GetProcessIntegrityLevel(process_handle, &level)) {
  66       ASSERT_STRING("UserKey::HasAccess: Cannot determine Integrity Level.");
  67       return false;
  68     }
  69     if (level <= base::LOW_INTEGRITY) {
  70       ASSERT_STRING("UserKey::HasAccess: Cannot write from Low Integrity.");
  71       return false;
  72     }
  73   }
  74   return true;
  75 }
  76
  77 }  // namespace rlz_lib