The Tor Browser: security/sandbox/win/src/handle_closer

security/sandbox/win/src/handle_closer_agent.cc@6474c204b198 (annotated)

security/sandbox/win/src/handle_closer_agent.cc

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // 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.
 #include "sandbox/win/src/handle_closer_agent.h"
 #include "base/logging.h"
 #include "sandbox/win/src/nt_internals.h"
 #include "sandbox/win/src/win_utils.h"
 namespace {
 // Returns type infomation for an NT object. This routine is expected to be
 // called for invalid handles so it catches STATUS_INVALID_HANDLE exceptions
 // that can be generated when handle tracing is enabled.
 NTSTATUS QueryObjectTypeInformation(HANDLE handle,
                                     void* buffer,
                                     ULONG* size) {
   static NtQueryObject QueryObject = NULL;
   if (!QueryObject)
     ResolveNTFunctionPtr("NtQueryObject", &QueryObject);
   NTSTATUS status = STATUS_UNSUCCESSFUL;
   __try {
     status = QueryObject(handle, ObjectTypeInformation, buffer, *size, size);
   } __except(GetExceptionCode() == STATUS_INVALID_HANDLE ?
                  EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
     status = STATUS_INVALID_HANDLE;
   }
   return status;
 }
 }  // namespace
 namespace sandbox {
 // Memory buffer mapped from the parent, with the list of handles.
 SANDBOX_INTERCEPT HandleCloserInfo* g_handles_to_close = NULL;
 bool HandleCloserAgent::NeedsHandlesClosed() {
   return g_handles_to_close != NULL;
 }
 // Reads g_handles_to_close and creates the lookup map.
 void HandleCloserAgent::InitializeHandlesToClose() {
   CHECK(g_handles_to_close != NULL);
   // Grab the header.
   HandleListEntry* entry = g_handles_to_close->handle_entries;
   for (size_t i = 0; i < g_handles_to_close->num_handle_types; ++i) {
     // Set the type name.
     char16* input = entry->handle_type;
     HandleMap::mapped_type& handle_names = handles_to_close_[input];
     input = reinterpret_cast<char16*>(reinterpret_cast<char*>(entry)
         + entry->offset_to_names);
     // Grab all the handle names.
     for (size_t j = 0; j < entry->name_count; ++j) {
       std::pair<HandleMap::mapped_type::iterator, bool> name
           = handle_names.insert(input);
       CHECK(name.second);
       input += name.first->size() + 1;
     }
     // Move on to the next entry.
     entry = reinterpret_cast<HandleListEntry*>(reinterpret_cast<char*>(entry)
         + entry->record_bytes);
     DCHECK(reinterpret_cast<char16*>(entry) >= input);
     DCHECK(reinterpret_cast<char16*>(entry) - input <
            sizeof(size_t) / sizeof(char16));
   }
   // Clean up the memory we copied over.
   ::VirtualFree(g_handles_to_close, 0, MEM_RELEASE);
   g_handles_to_close = NULL;
 }
 bool HandleCloserAgent::CloseHandles() {
   DWORD handle_count = UINT_MAX;
   const int kInvalidHandleThreshold = 100;
   const size_t kHandleOffset = sizeof(HANDLE);
   if (!::GetProcessHandleCount(::GetCurrentProcess(), &handle_count))
     return false;
   // Set up buffers for the type info and the name.
   std::vector<BYTE> type_info_buffer(sizeof(OBJECT_TYPE_INFORMATION) +
 * sizeof(wchar_t));
   OBJECT_TYPE_INFORMATION* type_info =
       reinterpret_cast<OBJECT_TYPE_INFORMATION*>(&(type_info_buffer[0]));
   string16 handle_name;
   HANDLE handle = NULL;
   int invalid_count = 0;
   // Keep incrementing until we hit the number of handles reported by
   // GetProcessHandleCount(). If we hit a very long sequence of invalid
   // handles we assume that we've run past the end of the table.
   while (handle_count && invalid_count < kInvalidHandleThreshold) {
     reinterpret_cast<size_t&>(handle) += kHandleOffset;
     NTSTATUS rc;
     // Get the type name, reusing the buffer.
     ULONG size = static_cast<ULONG>(type_info_buffer.size());
     rc = QueryObjectTypeInformation(handle, type_info, &size);
     while (rc == STATUS_INFO_LENGTH_MISMATCH ||
            rc == STATUS_BUFFER_OVERFLOW) {
       type_info_buffer.resize(size + sizeof(wchar_t));
       type_info = reinterpret_cast<OBJECT_TYPE_INFORMATION*>(
           &(type_info_buffer[0]));
       rc = QueryObjectTypeInformation(handle, type_info, &size);
       // Leave padding for the nul terminator.
       if (NT_SUCCESS(rc) && size == type_info_buffer.size())
         rc = STATUS_INFO_LENGTH_MISMATCH;
     }
     if (!NT_SUCCESS(rc) || !type_info->Name.Buffer) {
       ++invalid_count;
       continue;
     }
     --handle_count;
     type_info->Name.Buffer[type_info->Name.Length / sizeof(wchar_t)] = L'\0';
     // Check if we're looking for this type of handle.
     HandleMap::iterator result =
         handles_to_close_.find(type_info->Name.Buffer);
     if (result != handles_to_close_.end()) {
       HandleMap::mapped_type& names = result->second;
       // Empty set means close all handles of this type; otherwise check name.
       if (!names.empty()) {
         // Move on to the next handle if this name doesn't match.
         if (!GetHandleName(handle, &handle_name) || !names.count(handle_name))
           continue;
       }
       if (!::SetHandleInformation(handle, HANDLE_FLAG_PROTECT_FROM_CLOSE, 0))
         return false;
       if (!::CloseHandle(handle))
         return false;
     }
   }
   return true;
 }
 }  // namespace sandbox

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security/sandbox/win/src/handle_closer_agent.cc@6474c204b198 (annotated)

security/sandbox/win/src/handle_closer_agent.cc