sandbox/win/src/named_pipe_dispatcher.cc

   1 // Copyright (c) 2013 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 #include "sandbox/win/src/named_pipe_dispatcher.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/strings/string_split.h"
   9
  10 #include "sandbox/win/src/crosscall_client.h"
  11 #include "sandbox/win/src/interception.h"
  12 #include "sandbox/win/src/interceptors.h"
  13 #include "sandbox/win/src/ipc_tags.h"
  14 #include "sandbox/win/src/named_pipe_interception.h"
  15 #include "sandbox/win/src/named_pipe_policy.h"
  16 #include "sandbox/win/src/policy_broker.h"
  17 #include "sandbox/win/src/policy_params.h"
  18 #include "sandbox/win/src/sandbox.h"
  19
  20
  21 namespace sandbox {
  22
  23 NamedPipeDispatcher::NamedPipeDispatcher(PolicyBase* policy_base)
  24     : policy_base_(policy_base) {
  25   static const IPCCall create_params = {
  26       {IPC_CREATENAMEDPIPEW_TAG,
  27        {WCHAR_TYPE,
  28         UINT32_TYPE,
  29         UINT32_TYPE,
  30         UINT32_TYPE,
  31         UINT32_TYPE,
  32         UINT32_TYPE,
  33         UINT32_TYPE}},
  34       reinterpret_cast<CallbackGeneric>(&NamedPipeDispatcher::CreateNamedPipe)};
  35
  36   ipc_calls_.push_back(create_params);
  37 }
  38
  39 bool NamedPipeDispatcher::SetupService(InterceptionManager* manager,
  40                                        int service) {
  41   if (IPC_CREATENAMEDPIPEW_TAG == service)
  42     return INTERCEPT_EAT(manager, kKerneldllName, CreateNamedPipeW,
  43                          CREATE_NAMED_PIPE_ID, 36);
  44
  45   return false;
  46 }
  47
  48 bool NamedPipeDispatcher::CreateNamedPipe(IPCInfo* ipc,
  49                                           base::string16* name,
  50                                           uint32 open_mode,
  51                                           uint32 pipe_mode,
  52                                           uint32 max_instances,
  53                                           uint32 out_buffer_size,
  54                                           uint32 in_buffer_size,
  55                                           uint32 default_timeout) {
  56   ipc->return_info.win32_result = ERROR_ACCESS_DENIED;
  57   ipc->return_info.handle = INVALID_HANDLE_VALUE;
  58
  59   base::StringPiece16 dotdot(L"..");
  60
  61   for (const base::StringPiece16& path : base::SplitStringPiece(
  62            *name, base::string16(1, '/'),
  63            base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL)) {
  64     for (const base::StringPiece16& inner : base::SplitStringPiece(
  65              path, base::string16(1, '\\'),
  66              base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL)) {
  67       if (inner == dotdot)
  68         return true;
  69     }
  70   }
  71
  72   const wchar_t* pipe_name = name->c_str();
  73   CountedParameterSet<NameBased> params;
  74   params[NameBased::NAME] = ParamPickerMake(pipe_name);
  75
  76   EvalResult eval = policy_base_->EvalPolicy(IPC_CREATENAMEDPIPEW_TAG,
  77                                              params.GetBase());
  78
  79   // "For file I/O, the "\\?\" prefix to a path string tells the Windows APIs to
  80   // disable all string parsing and to send the string that follows it straight
  81   // to the file system."
  82   // http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx
  83   // This ensures even if there is a path traversal in the pipe name, and it is
  84   // able to get past the checks above, it will still not be allowed to escape
  85   // our whitelisted namespace.
  86   if (name->compare(0, 4, L"\\\\.\\") == 0)
  87     name->replace(0, 4, L"\\\\\?\\");
  88
  89   HANDLE pipe;
  90   DWORD ret = NamedPipePolicy::CreateNamedPipeAction(eval, *ipc->client_info,
  91                                                      *name, open_mode,
  92                                                      pipe_mode, max_instances,
  93                                                      out_buffer_size,
  94                                                      in_buffer_size,
  95                                                      default_timeout, &pipe);
  96
  97   ipc->return_info.win32_result = ret;
  98   ipc->return_info.handle = pipe;
  99   return true;
 100 }
 101
 102 }  // namespace sandbox