Add DACL and fix test for anonymous read-only memory

base/memory/shared_memory_win.cc

 // Copyright (c) 2011 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 "base/memory/shared_memory.h"
 
+#include <aclapi.h>
+
 #include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/rand_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 
 namespace {
 
 // Returns the length of the memory section starting at the supplied address.
 size_t GetMemorySectionSize(void* address) {
   MEMORY_BASIC_INFORMATION memory_info;
   if (!::VirtualQuery(address, &memory_info, sizeof(memory_info)))
@@ skipping 92 matching lines @@
     return false;
 
   // Check maximum accounting for overflow.
   if (options.size >
       static_cast<size_t>(std::numeric_limits<int>::max()) - kSectionMask)
     return false;
 
   size_t rounded_size = (options.size + kSectionMask) & ~kSectionMask;
   name_ = ASCIIToWide(options.name_deprecated == NULL ? "" :
                       *options.name_deprecated);
+  SECURITY_ATTRIBUTES sa = { sizeof(sa), NULL, FALSE };
+  SECURITY_DESCRIPTOR sd;
+  ACL dacl;
+
   if (options.share_read_only && name_.empty()) {
+    // Add an empty DACL to enforce anonymous read-only sections.
+    sa.lpSecurityDescriptor = &sd;
+    if (!InitializeAcl(&dacl, sizeof(dacl), ACL_REVISION))
+      return false;
+    if (!InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION))
+      return false;
+    if (!SetSecurityDescriptorDacl(&sd, TRUE, &dacl, FALSE))
+      return false;
+
     // Windows ignores DACLs on certain unnamed objects (like shared sections).
     // So, we generate a random name when we need to enforce read-only.
     uint64_t rand_values[4];
     base::RandBytes(&rand_values, sizeof(rand_values));
     name_ = base::StringPrintf(L"CrSharedMem_%016x%016x%016x%016x",
                                rand_values[0], rand_values[1],
                                rand_values[2], rand_values[3]);
   }
-  mapped_file_ = CreateFileMapping(INVALID_HANDLE_VALUE, NULL,
+  mapped_file_ = CreateFileMapping(INVALID_HANDLE_VALUE, &sa,
       PAGE_READWRITE, 0, static_cast<DWORD>(rounded_size), name_.c_str());
   if (!mapped_file_)
     return false;
 
   requested_size_ = options.size;
 
   // Check if the shared memory pre-exists.
   if (GetLastError() == ERROR_ALREADY_EXISTS) {
     // If the file already existed, set requested_size_ to 0 to show that
     // we don't know the size.
@@ skipping 122 matching lines @@
 void SharedMemory::UnlockDeprecated() {
   DCHECK(lock_ != NULL);
   ReleaseMutex(lock_);
 }
 
 SharedMemoryHandle SharedMemory::handle() const {
   return mapped_file_;
 }
 
 }  // namespace base