Fixing rlz mutex

0 - Remove special case for Vista.

1- Remove the low integrity logic, broken, wether or not to wait
   has nothing to do with setting the low integrity label, which
   was racy and (sometimes) broken.

2- Cleanup of style.

BUG=426573

Review URL: https://codereview.chromium.org/686733003

Cr-Commit-Position: refs/heads/master@{#301748}

2 files changed, 11 insertions, 48 deletions

diff --git a/rlz/win/lib/lib_mutex.cc b/rlz/win/lib/lib_mutex.cc
index 73dfade..d20fe21 100644
--- a/rlz/win/lib/lib_mutex.cc
+++ b/rlz/win/lib/lib_mutex.cc
@@ -1,67 +1,32 @@
 // Copyright (c) 2012 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.
-//
-// Mutex to guarantee serialization of RLZ key accesses.
 
 #include "rlz/win/lib/lib_mutex.h"
 
 #include <windows.h>
-#include <Sddl.h>    // For SDDL_REVISION_1, ConvertStringSecurityDescript..
-#include <Aclapi.h>  // For SetSecurityInfo
-
-#include "base/logging.h"
 #include "base/win/windows_version.h"
 
 namespace {
 
+const long kTimeoutMs = 5000L;
 const wchar_t kMutexName[] = L"{A946A6A9-917E-4949-B9BC-6BADA8C7FD63}";
 
-}  // namespace anonymous
+}  // namespace
 
 namespace rlz_lib {
 
-// Needed to allow synchronization across integrity levels.
-static bool SetObjectToLowIntegrity(HANDLE object,
-    SE_OBJECT_TYPE type = SE_KERNEL_OBJECT) {
-  if (base::win::GetVersion() < base::win::VERSION_VISTA)
-    return true;  // Not needed on XP.
-
-  // The LABEL_SECURITY_INFORMATION SDDL SACL to be set for low integrity.
-  static const wchar_t kLowIntegritySddlSacl[] = L"S:(ML;;NW;;;LW)";
-
-  bool result = false;
-  DWORD error = ERROR_SUCCESS;
-  PSECURITY_DESCRIPTOR security_descriptor = NULL;
-  PACL sacl = NULL;
-  BOOL sacl_present = FALSE;
-  BOOL sacl_defaulted = FALSE;
-
-  if (ConvertStringSecurityDescriptorToSecurityDescriptorW(
-          kLowIntegritySddlSacl, SDDL_REVISION_1, &security_descriptor, NULL)) {
-    if (GetSecurityDescriptorSacl(security_descriptor, &sacl_present,
-            &sacl, &sacl_defaulted)) {
-      error = SetSecurityInfo(object, type, LABEL_SECURITY_INFORMATION,
-                              NULL, NULL, NULL, sacl);
-      result = (ERROR_SUCCESS == error);
-    }
-    LocalFree(security_descriptor);
-  }
-
-  return result;
-}
-
 LibMutex::LibMutex() : acquired_(false), mutex_(NULL) {
-  mutex_ = CreateMutex(NULL, false, kMutexName);
-  bool result = SetObjectToLowIntegrity(mutex_);
-  if (result) {
-    acquired_ = (WAIT_OBJECT_0 == WaitForSingleObject(mutex_, 5000L));
-  }
+  mutex_ = CreateMutex(NULL, FALSE, kMutexName);
+  if (mutex_)
+    acquired_ = (WAIT_OBJECT_0 == WaitForSingleObject(mutex_, kTimeoutMs));
 }
 
 LibMutex::~LibMutex() {
-  if (acquired_) ReleaseMutex(mutex_);
-  CloseHandle(mutex_);
+  if (acquired_)
+    ReleaseMutex(mutex_);
+  if (mutex_)
+    CloseHandle(mutex_);
 }
 
 }  // namespace rlz_lib
diff --git a/rlz/win/lib/lib_mutex.h b/rlz/win/lib/lib_mutex.h
index 6992bea..d0f0eba 100644
--- a/rlz/win/lib/lib_mutex.h
+++ b/rlz/win/lib/lib_mutex.h
@@ -1,8 +1,6 @@
 // Copyright (c) 2012 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.
-//
-// Mutex to guarantee serialization of RLZ key accesses.
 
 #ifndef RLZ_WIN_LIB_LIB_MUTEX_H_
 #define RLZ_WIN_LIB_LIB_MUTEX_H_
@@ -10,13 +8,13 @@
 #include <windows.h>
 
 namespace rlz_lib {
-
+// Cross-process mutex to guarantee serialization of RLZ key accesses.
 class LibMutex {
  public:
   LibMutex();
   ~LibMutex();
 
-  bool failed(void) { return !acquired_; }
+  bool failed() const { return !acquired_; }
 
  private:
   bool acquired_;