Backed out changeset 9d28ee24c377 (bug 1573270) for xpcshell failures at toolkit/modules/tests/xpcshell/test_firstStartup.js on a CLOSED TREE

ipc/chromium/src/base/shared_memory_win.cc

@@ -111,10 +111,6 @@ bool SharedMemory::CreateInternal(size_t size, bool freezeable) {
   DCHECK(mapped_file_ == NULL);
   read_only_ = false;
 
-  // If the shared memory object has no DACL, any process can
-  // duplicate its handles with any access rights; e.g., re-add write
-  // access to a read-only handle.  To prevent that, we give it an
-  // empty DACL, so that no process can do that.
   SECURITY_ATTRIBUTES sa, *psa = nullptr;
   SECURITY_DESCRIPTOR sd;
   ACL dacl;
@@ -133,8 +129,6 @@ bool SharedMemory::CreateInternal(size_t size, bool freezeable) {
       return false;
     }
 
-    // Older versions of Windows will silently ignore the security
-    // attributes unless the object has a name.
     if (!mozilla::IsWin8Point1OrLater()) {
       name.AssignLiteral("MozSharedMem_");
       for (size_t i = 0; i < 4; ++i) {

ipc/gtest/TestSharedMemory.cpp

@@ -11,10 +11,6 @@
 #include "base/process_util.h"
 #include "mozilla/ipc/SharedMemory.h"
 
-#ifdef XP_WIN
-#include <windows.h>
-#endif
-
 namespace mozilla {
 
 // Try to map a frozen shm for writing.  Threat model: the process is
@@ -110,38 +106,4 @@ TEST(IPCSharedMemory, Reprotect)
 }
 #endif
 
-#ifdef XP_WIN
-// Try to regain write permissions on a read-only handle using
-// DuplicateHandle; this will succeed if the object has no DACL.
-// See also https://crbug.com/338538
-TEST(IPCSharedMemory, WinUnfreeze)
-{
-  base::SharedMemory shm;
-
-  // Create and initialize
-  ASSERT_TRUE(shm.CreateFreezeable(1));
-  ASSERT_TRUE(shm.Map(1));
-  auto mem = reinterpret_cast<char*>(shm.memory());
-  ASSERT_TRUE(mem);
-  *mem = 'A';
-
-  // Freeze
-  ASSERT_TRUE(shm.Freeze());
-  ASSERT_FALSE(shm.memory());
-
-  // Extract handle.
-  auto handle = base::SharedMemory::NULLHandle();
-  ASSERT_TRUE(shm.GiveToProcess(base::GetCurrentProcId(), &handle));
-  ASSERT_TRUE(shm.IsHandleValid(handle));
-  ASSERT_FALSE(shm.IsValid());
-
-  // Unfreeze.
-  bool unfroze = ::DuplicateHandle(GetCurrentProcess(), handle,
-                                   GetCurrentProcess(), &handle,
-                                   FILE_MAP_ALL_ACCESS, false,
-                                   DUPLICATE_CLOSE_SOURCE);
-  ASSERT_FALSE(unfroze);
-}
-#endif
-
 }  // namespace mozilla